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SpaceX Vehicles and Missions => SpaceX Starship Program => Topic started by: QuantumG on 05/14/2011 01:17 am

Title: Zubrin's Falcon Heavy Mars Mission
Post by: QuantumG on 05/14/2011 01:17 am
http://on.wsj.com/mNABsj  (note that you may have to play "google the headline" to read this)

My summary:

Flight 1. Falcon Heavy puts Earth Return Vehicle into Mars orbit.
Flight 2. Falcon Heavy puts Mars Ascent Vehicle on Mars surface.
Flight 3. Falcon Heavy sends Crew Transfer Vehicle to Mars to precise landing.
Crew spends 500 days on the surface, uses the MAV to ascend to the ERV and return to an ocean landing.

The ERV has a LOX/Kero engine, presumably preloaded with kero only.

The MAV has a LOX/Methane engine and a chemical reactor to make oxygen from the Mars atmosphere (note that Zubrin isn't advocating making Methane on the surface.. presumably to keep the power requirements under 10 kW).

The CTV has maneuvering thrusters only and carries 2500 kg of provisions for a crew of two for 3 years.  There's no discussion of artificial gravity.

All three vehicles are Dragon derived.

Choice quotes:

   "we could send expeditions to Mars at half the cost to launch a Space Shuttle flight."

  "There is no question that this plan involves considerable risk, and a variety of missions, technology developments and testing programs in advance might reduce that risk. But if we try to do even a significant fraction before committing to the mission, we will never get to Mars.  [..] If we want to reduce risk to human life, there are vastly more effective ways of doing so than by spending $10 billion per year for the next two or three decades on a human spaceflight program mired in low Earth orbit."

I think the only more extreme position I've ever read is one-way-to-stay.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Michael Bloxham on 05/14/2011 01:45 am
I would assume that the 11 tonnes surface payload (from only 14.5 tonnes in orbit) would include the wet-mass of the descent stage. Otherwise such a high payload mass fraction (75%) is unrealistic. I think the current state-of-the-art (MSL) is less than 30%.

There is also the problem of constrained PLF size on the Falcon Heavy. If the same ballistic-coefficient at aero-entry as MSL were assumed, then an aeroshell with a diameter of at least 9 meters would be required. The current Falcon Heavy PLF is only 5.2m in diameter.

- Mike
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: QuantumG on 05/14/2011 01:50 am
Who knows how Zubrin came up with those numbers.. I expect dice were involved.

People have been telling him about the heat shield requirements for how many years now?  At least he's not talking about landing 30 tons on the surface with a heat shield this time.

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Zed_Noir on 05/14/2011 02:00 am
I got a question about storing kerosene in a zero-G environment  for extended period of time. Have any experiment been done to find if the kerosene is usable after several months in Zero-G?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Warren Platts on 05/14/2011 02:07 am
I got a question about storing kerosene in a zero-G environment  for extended period of time. Have any experiment been done to find if the kerosene is usable after several months in Zero-G?

Huh? Kerosine is kerosine: it doesn't care about gravity, within reason....
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: QuantumG on 05/14/2011 02:28 am
To answer the question you meant to ask.. yes, kero is space storable.

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: wintermuted on 05/14/2011 03:11 am
To answer the question you meant to ask.. yes, kero is space storable.

You do have to keep it warm.  Not sure if it would return to usable form if you let it freeze/gel then thaw..

wm
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Patchouli on 05/14/2011 03:55 am
I would assume that the 11 tonnes surface payload (from only 14.5 tonnes in orbit) would include the wet-mass of the descent stage. Otherwise such a high payload mass fraction (75%) is unrealistic. I think the current state-of-the-art (MSL) is less than 30%.

There is also the problem of constrained PLF size on the Falcon Heavy. If the same ballistic-coefficient at aero-entry as MSL were assumed, then an aeroshell with a diameter of at least 9 meters would be required. The current Falcon Heavy PLF is only 5.2m in diameter.

- Mike

There is a way around that an inflatable aeroshell.

I seen NASA plans where a scaled up version is used to land 60 to 80 tons on Mars.
http://www.prlog.org/10316724-ilc-dover-celebrates-successful-irve-inflatable-aeroshell-flight-test.html
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Michael Bloxham on 05/14/2011 04:36 am
Inflatables are even less mass-efficient than rigid aeroshells.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: QuantumG on 05/14/2011 04:46 am
Before this dissolves into a debate of technology.. and I thoroughly admit to having started that debate.. I have to say I would much rather hear people's opinions on the quotes.  Zubrin doesn't get up on stage or write for the newspapers to convince the technical audience.  In fact, I'm not terribly sure I've ever heard Zubrin say much to convince the technical audience. 

As I see it, his argument is simple: risk to astronaut life, be it immediate mission failure risk or long term health risk, is worth it to go to Mars.. and he typically goes on to say that the possibility of finding life is the best reason to go to Mars, with eventual colonization being a distant second.

How do you feel about that?  Is his "right stuff" mentality correct?  Is NASA way too cautious these days?  Or is he just shouting into the wind?

(for anyone who cares, my personal belief is that NASA will never do another mission with the level of risk of Apollo 8.. and their biggest fear is that another set of astronauts will some day die and the entirety of HSF will be shut down.  Whether or not you think that is good or bad is irrelevant, it's the way it is, deal with it.)
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Michael Bloxham on 05/14/2011 05:04 am
"There is no question that this plan involves considerable risk, and a variety of missions, technology developments and testing programs in advance might reduce that risk. But if we try to do even a significant fraction before committing to the mission, we will never get to Mars."

This statement is both foolish and redundant. Risks to human life must be qualified to a humanstic degree in any scenario. Not attempting a dangerously premature human mission to Mars doesn't mean we will never get there. I agree with the above poster; the risk is just the opposite.

- Mike
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Michael Bloxham on 05/14/2011 05:20 am
With that said, I think the better way forward is to rely on well-developed and reliable technologies - e.g. low-ballistic coefficient rigid aeroshells such as the type used for robotic probes - rather than less-understood hypothetical technologies. If Zubrin wants a Humans-to-Mars mission on the cheap, then I would suggest the development of a small man-rated lander utilizing a progression of MSL-type technology - rather than relying on completely new and untested technologies. That means a capsule-shaped entry vehicle with a large diameter rigid heatshield. E.g. 9m - far larger than what Falcon Heavy can accomodate, but within the bounds of SLS, etc. Although I admit there may be potential for a much larger PLF on Falcon Heavy. But could it be big enough?

- Mike
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: QuantumG on 05/14/2011 05:43 am
Well, Zubrin has already made the argument for bigger rockets.. how does these technical objections change the basic philosophy?

What is worth the risk of astronaut's lives?  How much risk is acceptable?  These are deep questions that I wish Zubrin would ask, instead of declaring answers, because so many people object to his answers and then feel no need to ask themselves the questions.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Downix on 05/14/2011 05:50 am
  "There is no question that this plan involves considerable risk, and a variety of missions, technology developments and testing programs in advance might reduce that risk. But if we try to do even a significant fraction before committing to the mission, we will never get to Mars.  [..] If we want to reduce risk to human life, there are vastly more effective ways of doing so than by spending $10 billion per year for the next two or three decades on a human spaceflight program mired in low Earth orbit."
And at this point I had to start laughing, for I know what $10 billion per year with the shuttle program would deliver, using some pieces of work Zubrin himself even discussed in the past.

In the 1990's, General Dynamics proposed a program called "Early Lunar Access" using a pairing of Shuttle and ELV to deliver a lunar program for low cost and rapid development.  Studying this, and applying todays capabilities, let us explore what can be done.

Let us assume that we push the Shuttle to maximum capability, as many launches as we can safely, considering we have only one launch pad and three orbiters. As a Shuttle takes 2 months to turn it around on average, that means each shuttle can be launched 6 times per year, maximum.  I'll divide that by half, as these are old vehicles, for a total of 9 launches.  Knowing the numbers for the Space Shuttle, this would cost a grand total of $5.1 billion per year.  Now, we need to be able to afford the craft, so I will take an approach of adapting the Nautilus-X program and cost projections to this combined Shuttle/EELV approach.  It's cost is $3.7 billion for R&D and construction, with testing of equipment on the ISS.  Because we still have the Shuttle, the spacecraft does not require automated assembly systems, which means speeding up of development.  Now, 8 assembly launches will not have a complete system, but it will have all of the components *but* the inflatable habs and the fuel units.  $10 billion a year, subtracting the Shuttle and vehicle costs comes to $8.8 billion.  The inflatable habs, fuel, and the lander would be lifted with traditional EELV's, requiring 3 heavy launches (two Delta and one Atlas 551) to accomplish the final assembly in the 2 weeks after the initial crew launch, utilizing the crew left by the last Shuttle launch, all three vehicles utilizing both Cape EELV launch sites and the Vandenburg launch site.  This would cost $1.1 billion, making the whole cost of the Mars mission $9.9 billion.  No new launch vehicles, and no use of technology we do not have within the near future.

Now, let us compare to Zubrin's plan here.  Unlike the Shuttle, which has the tools and capability for on-orbit assembly, Falcon is just a BFR.  You'd have more launches to reach the same capability, even if each launch could lift more, due to the need for on-orbit assembly.  By a calculation, for the same level of craft as the Nautilus-X, it would take 20 Falcon 9 Heavy launches to reach the same level of capability.  While yes, the launch strength of F9H is higher, it lacks any kind of on-orbit assembly system, requiring an automated deploy, tug, and assembly, which would increase the weight of each payload.  Based on the automated Russian assembly of modules for both Mir and ISS, and comparing to the weight of those brought by the Shuttle with their capability for the ISS, each module would have to add approximately 40% weight to reach the same level of capability based on history with not one, but 4 space agencies.  This of course means the craft would need a more powerful engine, which adds even more weight to the process, further increasing the number of flights.  It would need 12 flights for the main structure, 3 more for the habitat, and 5 for the fuel, totalling 20 flights. At $150 million per launch, that comes to $3 billion.  The turnaround for Falcons is not fast enough, nor do they have the number of pads needed to enable a staffed spaceship to handle the final stage of assembly. And adding to it, the development cost of the vehicle would itself be higher, due to it's need to self-assemble.  You'd be looking, based on experience we've had with the ISS, at the craft itself having the cost at least doubled, bringing it to $7.4 billion.  So, $3 billion + $7.4 billion == More expensive than the Shuttle + EELV program.

Welcome to space flight.  You're talking a Mars mission, and claiming superiority of one system over another over cost, while ignoring the full capability of the other system.  This is the exact kind of mission the Shuttle is ideal for.  You're not going to Mars in a capsule, you need a full spaceship.  And a full spaceship is not going to be all-up, but assembled on-orbit. For on-orbit Assembly, nothing beats the Space Shuttle.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Michael Bloxham on 05/14/2011 06:06 am
FWIW, Zubrin is proposing vehicles that accomodate a crew of only 2 each. With the 53 tonne throw-weight of the Falcon Heavy, it is not implausible that these could be each delivered to Mars in one piece - without requiring orbital assembly. (See http://forum.nasaspaceflight.com/index.php?topic=17360.msg685877#msg685877 and http://forum.nasaspaceflight.com/index.php?topic=24909.0)

Edit: Also, Nautilus-X is a joke. :D

- Mike
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: QuantumG on 05/14/2011 06:24 am
Edit: Also, Nautilus-X is a joke. :D

It's a graphic demonstration that people are desperate to see large structures in space and if that means we need better propulsion to push around "space ships" instead of capsules then that's what NASA should be working on.

Zubrin holds the opposing view to that.. he really doesn't care how you get there, it's just an endurance test, although he holds some opinions on what means will be the fastest to develop.

And that's the fundamental disconnect.. Zubrin wants to get going already and the other camp wants to build the space equivalent of a Winnebago.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Sen on 05/14/2011 06:33 am
that sums up what i was going to post nicely. Enough waiting on X super rocket or Y development, just plan with what we have  and get going. Thats the sentiment anyway. Im not saying its going to work, but Thiel, Elon, and now Zubrin are thinking about it in that way. Zubrins had a bit of a rebirth on the issue, having gotten so wrapped up in Ares, the booster named for his proposal. A few more years, a few billion dollars and they will try. Or at least try to try. Which is more then waiting on 2018 to try and try.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: QuantumG on 05/14/2011 06:41 am
just plan with what we have  and get going. Thats the sentiment anyway.

And the conclusion you (hopefully) come to is the conclusion Zubrin has come to: with existing technology (and economics!) the kind of architecture you come up with has massive risks.  Not just crew safety but also mission risk.

The general response to those risks is to say "we're going to kill the crew" and "this will never work", but some minority of people say "so what! let's go!"
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Sen on 05/14/2011 07:48 am
just plan with what we have  and get going. Thats the sentiment anyway.

And the conclusion you (hopefully) come to is the conclusion Zubrin has come to: with existing technology (and economics!) the kind of architecture you come up with has massive risks.  Not just crew safety but also mission risk.

The general response to those risks is to say "we're going to kill the crew" and "this will never work", but some minority of people say "so what! let's go!"


I dont come to a conclusion, well not exactly. On the face of it this looks high risk and low margin before you even get into the actual hardware details/development. To borrow a quote, success does not seem to be a likely outcome. I was speaking to the mindset. Rspec if he were still around would say you could do Mars with a space suit, a fire extinguisher for propulsion and a yellow rubber duck for entry. I wouldn't count on it, however.

Add a few more Fh launches, a bigelow module or two and some margin and something might be workable. But that wouldn't be this plan, and would cost more "then a single shuttle launch". But getting back to the sentiment, it COULD be planned based on what we have or may soon have, and not forever on that "in a decade or two" horizon that generations have been born (and died) waiting for.  And to be honest, Mars for a few or a dozen billion private sector dollars might happen, although its not a given, or even particularly likely to come together in all honesty. Mars for a few hundred billion government dollars will never happen, ever.

Edit: Removed the 2am Snark :)
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: MATTBLAK on 05/14/2011 10:09 am
Doing a Mars mission with only two people is pretty risky: I know the 2x crew paradigm is to minimise consumables and big, habitable volumes, etc. But if one person becomes sick or injured during a long mission, then that mission is stuffed. Kaput. With four people - if one becomes incapacitated or dead - you've still got enough manpower to perform a mission. Although, I do think 2x crew might be adequate for a NEO, Mars flyby or mission to Deimos.

Whether the main constraints are payload fairing size, aeroshell design or just plain HLV lifting power: 50 tons-to-LEO or 80 tons each have their own limitations. Workarounds MUST get priority in ANY Mission Architecture design. If a 53 metric ton HLV is the main constraint, I would prefer building up a propellant cache at L-2. Send the Mars Transfer Vehicle/Hab module to the Propellant Depot to await the EDS. Then, with the longest & widest EDS you can launch on the biggest payload fairing for a Falcon Heavy (6.5 meters wide? 7 meters?) send that EDS to the Depot to fill up, mate with the MTV/HAB then proceed to Mars.

Aeroshell/heatshield? What about a hybrid, semi-rigid parasol/inflatable? These are questions for future engineers and designers to solve.

By the way: I interviewed Shannon Lucid in 1997 and asked about a joke someone made on a SpaceLab mission -- they had made a remark about "wishing the OMS had enough propellant to light up and really send them someplace, after two weeks looking at the Earth".

I asked Doctor Lucid if the combined habitable volume of the Shuttle Mid & Flightdeck plus the SpaceLab module was enough for six or seven people for many months. She said; "Oh sure! Just so long as the toilet kept working and there was plenty of food and water; let's go to Mars or someplace."

Therefore, I've often thought the claims of needing a great deal of habitable volume for a Marsbound crew are overstated. A crew of four would be just fine in a space the size of a double SpaceHab module plus maybe a little bit more.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: pathfinder_01 on 05/14/2011 10:34 am
Welcome to space flight.  You're talking a Mars mission, and claiming superiority of one system over another over cost, while ignoring the full capability of the other system.  This is the exact kind of mission the Shuttle is ideal for.  You're not going to Mars in a capsule, you need a full spaceship.  And a full spaceship is not going to be all-up, but assembled on-orbit. For on-orbit Assembly, nothing beats the Space Shuttle.

While the shuttle may be good at on orbit assembly, there are other ways to do it. 

For instance a space station can provide robot arms, air lock, and act as a fuel depot.

Not all parts need (or should) be lifted via falcon heavy.  A disposable tug can be attached to one end of the module and the amount of assembly can be low.(i.e. While you are not going to Mars in something the size of a capsule, you also are not doing it in something the size of MIR or the ISS. Something larger than Salyut could do.).
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: QuantumG on 05/14/2011 10:41 am
Well, ya know, Zubrin at least provided some mass numbers.. and a total dollar amount.  They're pretty far from accurate but so far he's one up.

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: MATTBLAK on 05/14/2011 10:47 am
Quantum; can you provide a link for Bob Zubrin's figures, or a paper? I've looked at the Mars Society website first but don't see anything immediately apparent.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: pathfinder_01 on 05/14/2011 10:48 am
Well, ya know, Zubrin at least provided some mass numbers.. and a total dollar amount.  They're pretty far from accurate but so far he's one up.



Zurbin is too optimistic about cost and mass and safety. He erodes any faith in his plans. He also is unable to see the forest for the trees. I watched the mars society go against Vasmir of all things becuase it didn't fit into his Mars direct plans. Even if Vasmir can't get you to mars in 39 days due to power issues there are a heck of a lot of other mars related uses for it but to him if we don't start going to a dry dead world called mars at once, then it is the end of the world. No other form of development is worth it.

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: QuantumG on 05/14/2011 10:48 am
Quantum; can you provide a link for Bob Zubrin's figures, or a paper? I've looked at the Mars Society website first but don't see anything immediately apparent.

I started the thread with the link :)   You may need to google the headline to read it.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: QuantumG on 05/14/2011 10:54 am
Zurbin is too optimistic about cost and mass and safety.

He's not optimistic about safety, he's blasé about safety.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: pathfinder_01 on 05/14/2011 11:00 am
Zurbin is too optimistic about cost and mass and safety.

He's not optimistic about safety, he's blasé about safety.

To the point where his mission would likely fail. People should take risks but the way he blows off radiation and low g risks is disturbing. If you don't have plans and options for the foreseeable and if you don't retire some risk then you mission is very likely to fail and the consequences could slow exploration. I don't think watching a guy die from radiation on the first mission makes for a good start.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: MATTBLAK on 05/14/2011 11:02 am
Quantum; can you provide a link for Bob Zubrin's figures, or a paper? I've looked at the Mars Society website first but don't see anything immediately apparent.

I started the thread with the link :)   You may need to google the headline to read it.


Right, thanks: now done that. My bookmarking of threads I've contributed to always defaults to the later pages! ;)

Trouble is: several of the links I've followed seem sparse on real details and often its the same short set of paragraphs, over and over. But now having read what details there are -- despite what I just said above about Habitable volume not being such an issue -- I find the mission as described by Zubrin to be just one step short of loopy. I mean, seriously?! Even with only a crew of two, using a set of the fairly teeny Dragon capsules as Habitation modules to & from Mars AND on the Martian surface itself?! *Unless I'm missing a major plot-point or piece if information*: This all smacks a bit of desperation, and of a story which has finally lost the plot. Dragon capsule/spacecraft are what they are: they are NOT some sort of Doctor Who's TARDIS -- bigger on the inside than the outside.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: QuantumG on 05/14/2011 11:11 am
The Russian space program had a number of early fatalities.. I'd say it did wonders for them - sort of a trial by fire.  It forced them to decide if spaceflight really was important.. they decided it was.  Despite the death of those on Challenger and Columbia, the US still hasn't made that decision.  In fact, you could say the US public has made the negative decision.. it's not important, and that's what upsets Zubrin.

Unless I'm missing a major plot-point or piece if information.

What you're missing is Zubrin's worldview.. Apollo didn't have a toilet and the crew got by.. how?  They had the "right stuff".  Human spaceflight is just an ordeal that is to be endured.  We all die, why not die on Mars?  And so on.

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: pathfinder_01 on 05/14/2011 11:22 am
The Russian space program had a number of early fatalities.. I'd say it did wonders for them - sort of a trial by fire.  It forced them to decide if spaceflight really was important.. they decided it was.  Despite the death of those on Challenger and Columbia, the US still hasn't made that decision.  In fact, you could say the US public has made the negative decision.. it's not important, and that's what upsets Zubrin.

Unless I'm missing a major plot-point or piece if information.

What you're missing is Zubrin's worldview.. Apollo didn't have a toilet and the crew got by.. how?  They had the "right stuff".  Human spaceflight is just an ordeal that is to be endured.  We all die, why not die on Mars?  And so on.



The US and Russia are about equal in accidents with the US leading.

IMHO it isn't death but how it happened that can make a big difference. 

The Apollo fire could be forgiven in the rush to beat the Russians.  Challenger and Columbia were lost to problems that NASA knew about and choose to ignore.  The Soyuz ones were lost due to lack of testing from the looks of it. There is something different about didn't test enough to find the flaw than knew about the flaw and did it anyway.

Toilet or no Toilet a mars crew is going to face tough odds. The issuse isn't crew comfort. It is survival and is the mission worth the cost? One big objection I have to Mars direct is that little to nothing is reused and so on every mission you must send everything all over again.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: QuantumG on 05/14/2011 11:33 am
One big objection I have to Mars direct is that little to nothing is reused and so on every mission you must send everything all over again.

Zubrin has argued that the habitats, rovers, power plants, chemical factories, etc, etc, left on the surface of Mars are all reusable.. you would send new stuff every mission but it would be to build up a greater capability each mission.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: MATTBLAK on 05/14/2011 11:46 am
Quantum; I'm not missing Zubrin's worldview at all: I've been reading his stuff for 20 years or so. And when I read his 'Case For Mars' book about Mars Direct etc, I thought it was one of the most exciting things that I've read in my life. I admire his persistence and I love his sheer passion. But with this latest proposal, my point is this: his new  mission 'design' smacks of desperation and for me, is a step too far away from credibility. So when someone like me, virtually a 'Zubrinite' says this, you know something is wrong.

I'd like those of us in this discussion to ponder some credible Mars missions, using Falcon Heavy, Dragon and some near off-the-shelf equipment. For a kickoff - if you're interested - A Dragon acting as the Command & Control/Earth Return capsule, 1x Hab Module & 1x combined 'Storm Shelter'/food & water pantry +plus 1x Airlock: all launched by a single Falcon Heavy. Visualize something like a Dragon docked to an ISS Node and an MPLM and you might get a rough comparison. Also, this module group would use 3 or 4 sets of Dragon solar arrays for power. Once launched, the Dragon crew of 2 Astronauts perform a Transposition & Docking manuever not unlike what Apollo did between the CSM & LM. Then, they rendezvous and dock with an awaiting Mission propulsion 'stack'

Preceding the Dragon and Hab/Supplies/Airlock modules are enough F.H. launches to deploy a stack of Propulsion Modules - 2x storable prop stages: 1x for entering Mars orbit near Deimos (low delta-V demands) and 1x later for Trans-Earth Injection. To leave Earth for Trans-Mars Injection, is it 2x or 3x 50-ton high-energy LOX/LH2-fueled Earth Departure stages that would be needed to send the Dragon and its Hab modules on their way? We're assuming that these would be state-of-the-art, lightweight Aluminium/Lithium and/or Carbon-fiber constructs. Or maybe one of them could even be inflatable. Either way; all modules have lots of polyethylene for radiation shielding, coupled with the crew's water supply. Maximum use of water & air recycling, of course.

Mission Goal: survey and sample Deimos and rendezvous with group of Mars Sample Return probes awaiting collection near Deimos. Future Missions: Phobos survey and possible setup of man-tended Phobos space station. Later mission(s), if funding can be found - rendezvous in high Martian orbit with an honest, gee-whiz manned Mars Lander for finally going down to the surface. There, they will meet a pre-deployed Ascent Vehicle that will later take them back to the Dragon & Hab 'Mothership' in high orbit - near Phobos or Deimos. But also on the surface are a pre-deployed Hab Module and Pressurized Exploration Rover. By this stage, I'd say a crew of 3 or 4 is needed.

Now: all the above represents a step-by-step, incremental approach, using Space-X's useful Dragon and it's derivatives and the Falcon Heavy, which would benefit by eventual introduction of improved Merlin engines (Merlin 2, 1.7 million pound+plus thrust engine?) and high-energy upper stages.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: QuantumG on 05/14/2011 11:53 am
Great Matt, if you want to consider that do so.. but use numbers.

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: MATTBLAK on 05/14/2011 12:06 pm
Great Matt, if you want to consider that do so.. but use numbers.



Confession: I ain't no Maths guy! I'm just a third-rate science fiction writer and second-rate space blogger. There are far smarter people here than me with actual engineering training that can crunch numbers. Suffice to say, we know what Falcon Heavy is supposed to lift: 53 metric tons -minus Dragon (upgraded with more propellant & shielding) = 41 tons. Now, divide whats left among the Hab/Storm Shelter/Airlock.

Propulsion Stages: Dry weight, engines and structures? Don't know - 8 or 9 tons, leaving approximately 40 tons for propellant?

Just trying to keep the discussion going, prompting more learned folk than I. I'll be curious to read the results tomorrow: Its midnight down here and I've got an early start tomorrow.... ;)
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Downix on 05/14/2011 04:05 pm
Great Matt, if you want to consider that do so.. but use numbers.



Confession: I ain't no Maths guy! I'm just a second-rate science fiction writer and space blogger. There are far smarter people here than me with actual engineering training that can crunch numbers. Suffice to say, we know what Falcon Heavy is supposed to lift: 53 metric tons -minus Dragon (upgraded with more propellant & shielding) = 41 tons. Now, divide whats left among the Hab/Storm Shelter/Airlock.

Propulsion Stages: Dry weight, engines and structures? Don't know - 8 or 9 tons, leaving approximately 40 tons for propellant?

Just trying to keep the discussion going, prompting more learned folk than I. I'll be curious to read the results tomorrow: Its midnight down here and I've got an early start tomorrow.... ;)
Try 19 mT per habitation module, 21 mT for the solar array, 11 mT for the engines... then add fuel, 40 mT of it
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Robotbeat on 05/14/2011 04:26 pm
21mT for a solar array? Is a multi-Megawatt solar array really necessary? It would be enough for a powerful SEP stage (and that's a viable concept for a Mars mission, in my opinion), but hardly needed for just mission power!
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Downix on 05/14/2011 06:37 pm
21mT for a solar array? Is a multi-Megawatt solar array really necessary? It would be enough for a powerful SEP stage (and that's a viable concept for a Mars mission, in my opinion), but hardly needed for just mission power!
Consider radiation decay for a chemical engine of this weight.  Your array would loose 5% of it's total capability every 3 weeks.  Take that over two 6 month trips.  Figure out your power need, then work backwards and double it in case circuits are broken in between cells. 

Let us do the math.  I will assume that this is a low-capacity 2-person mars mission, with a Dragon and an Almaz-sized/capability module with a propultion system which is chemical, not electric in order to reduce the power demands.  Almaz consumed 8500W/h, and Dragon's demands appear to be closer to 1500W/h, so let us get an aim-point of 10kW total demand after 12 months of exposure to solar radiation.  What has been found is, per solar incident, solar panels decay at the rate of 2%.  During active periods (and we're entering into one right now), there are between 200-250 of these incidents per year.  So, let us calculate, 10kW, growing by 2% each time over 250 times, gives us  1484.13 kW.  Doubling that, we will need roughly 3MW of power in order to guarantee survival for return.  Each panel of the ISS generates 246kW of power, so we would need 6 of them to guarantee power supply.  When you take this with the weight of the panels, four of them with the truss needed to support them at 14mT.  Adding 50% more would result in 21mT.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: alexw on 05/14/2011 07:48 pm
What's a "W/h" intended to mean?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Downix on 05/14/2011 08:03 pm
What's a "W/h" intended to mean?
Watt/hour.  Basic electricity term to determine power demand.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: telomerase99 on 05/14/2011 09:13 pm
  "There is no question that this plan involves considerable risk, and a variety of missions, technology developments and testing programs in advance might reduce that risk. But if we try to do even a significant fraction before committing to the mission, we will never get to Mars.  [..] If we want to reduce risk to human life, there are vastly more effective ways of doing so than by spending $10 billion per year for the next two or three decades on a human spaceflight program mired in low Earth orbit."
And at this point I had to start laughing, for I know what $10 billion per year with the shuttle program would deliver, using some pieces of work Zubrin himself even discussed in the past.

In the 1990's, General Dynamics proposed a program called "Early Lunar Access" using a pairing of Shuttle and ELV to deliver a lunar program for low cost and rapid development.  Studying this, and applying todays capabilities, let us explore what can be done.

Let us assume that we push the Shuttle to maximum capability, as many launches as we can safely, considering we have only one launch pad and three orbiters. As a Shuttle takes 2 months to turn it around on average, that means each shuttle can be launched 6 times per year, maximum.  I'll divide that by half, as these are old vehicles, for a total of 9 launches.  Knowing the numbers for the Space Shuttle, this would cost a grand total of $5.1 billion per year.  Now, we need to be able to afford the craft, so I will take an approach of adapting the Nautilus-X program and cost projections to this combined Shuttle/EELV approach.  It's cost is $3.7 billion for R&D and construction, with testing of equipment on the ISS.  Because we still have the Shuttle, the spacecraft does not require automated assembly systems, which means speeding up of development.  Now, 8 assembly launches will not have a complete system, but it will have all of the components *but* the inflatable habs and the fuel units.  $10 billion a year, subtracting the Shuttle and vehicle costs comes to $8.8 billion.  The inflatable habs, fuel, and the lander would be lifted with traditional EELV's, requiring 3 heavy launches (two Delta and one Atlas 551) to accomplish the final assembly in the 2 weeks after the initial crew launch, utilizing the crew left by the last Shuttle launch, all three vehicles utilizing both Cape EELV launch sites and the Vandenburg launch site.  This would cost $1.1 billion, making the whole cost of the Mars mission $9.9 billion.  No new launch vehicles, and no use of technology we do not have within the near future.

Now, let us compare to Zubrin's plan here.  Unlike the Shuttle, which has the tools and capability for on-orbit assembly, Falcon is just a BFR.  You'd have more launches to reach the same capability, even if each launch could lift more, due to the need for on-orbit assembly.  By a calculation, for the same level of craft as the Nautilus-X, it would take 20 Falcon 9 Heavy launches to reach the same level of capability.  While yes, the launch strength of F9H is higher, it lacks any kind of on-orbit assembly system, requiring an automated deploy, tug, and assembly, which would increase the weight of each payload.  Based on the automated Russian assembly of modules for both Mir and ISS, and comparing to the weight of those brought by the Shuttle with their capability for the ISS, each module would have to add approximately 40% weight to reach the same level of capability based on history with not one, but 4 space agencies.  This of course means the craft would need a more powerful engine, which adds even more weight to the process, further increasing the number of flights.  It would need 12 flights for the main structure, 3 more for the habitat, and 5 for the fuel, totalling 20 flights. At $150 million per launch, that comes to $3 billion.  The turnaround for Falcons is not fast enough, nor do they have the number of pads needed to enable a staffed spaceship to handle the final stage of assembly. And adding to it, the development cost of the vehicle would itself be higher, due to it's need to self-assemble.  You'd be looking, based on experience we've had with the ISS, at the craft itself having the cost at least doubled, bringing it to $7.4 billion.  So, $3 billion + $7.4 billion == More expensive than the Shuttle + EELV program.

Welcome to space flight.  You're talking a Mars mission, and claiming superiority of one system over another over cost, while ignoring the full capability of the other system.  This is the exact kind of mission the Shuttle is ideal for.  You're not going to Mars in a capsule, you need a full spaceship.  And a full spaceship is not going to be all-up, but assembled on-orbit. For on-orbit Assembly, nothing beats the Space Shuttle.

Who needs the shuttle when we have ISS? Why not use capsules to ISS on the cheap and space walk from ISS to do on orbit assembly? That way we don't have to pay to launch an entire on orbit assembly platform in the shape of shuttle when we have one that sits up in space and cost us $100 billion.

Lets use the ISS!
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: ugordan on 05/14/2011 09:14 pm
What's a "W/h" intended to mean?
Watt/hour.  Basic electricity term to determine power demand.

I think you mean Watt-hour (W·h).  Power divided by time doesn't make much sense. Power multiplied by time on the other hand is a measure of energy, which I assume is what you're thinking of.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Downix on 05/14/2011 09:32 pm

Who needs the shuttle when we have ISS? Why not use capsules to ISS on the cheap and space walk from ISS to do on orbit assembly? That way we don't have to pay to launch an entire on orbit assembly platform in the shape of shuttle when we have one that sits up in space and cost us $100 billion.

Lets use the ISS!
You'd have to increase the side of the ISS crew in order to turn it into an assembly location, plus the arm does not have a long enough reach as it is, so you would need to expand the ISS a bit to handle this kind of role.  Not saying it can't be done, but do understand that it will need more work for this.

Incidentally, utilizing a 70mT launch vehicle with a larger payload size (J-130 w/ 8m shroud) would enable a two-HLV, three-EELV scenario, further reducing the cost to both develop and deploy.

This has gotten me thinking a bit for a mission for AJAX, with the existing budget.  Time to number crunch.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: pathfinder_01 on 05/14/2011 10:20 pm
You'd have to increase the side of the ISS crew in order to turn it into an assembly location, plus the arm does not have a long enough reach as it is, so you would need to expand the ISS a bit to handle this kind of role.  Not saying it can't be done, but do understand that it will need more work for this.


Depends on which arm you are talking about. The ESA robot arm planed to be added next year can inch worm from attachment point to attachment point. The larger Canada arm can too. Just put attachment points on the Craft and it could in theory go there...plus the craft itself may have a robot arm.

A mars ship's hab module could also function as shelter for the crew that is assembling the spacecraft.   

Big work but not that huge. It also does not need to be totally assemebled just assembled enough that it can function on it own's when undocked.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: sanman on 05/14/2011 10:27 pm
What about something like Russia's plan to set up a robotic base on the Moon? How about adapting that idea for Mars, so that a series of robot missions are sent there, building up a robotic infrastructure that could be re-purposed for supporting humans who would be sent at some later date.

That way, once humans arrive, they can simply plug into that infrastructure, which could comfortably support them indefinitely, should unforeseen events prevent the return portion of their journey.

So this type of approach would allow one-way-to-stay as a fallback position, if the planned return leg of the mission didn't work out for whatever reason.

I'd like to see humans start living on Mars as soon as possible, to make it part of our future. As for finding out whether life once existed on Mars, that's about making Mars part of our past, and it's of lesser importance to me. The sooner people start living on Mars, the sooner we can start turning it towards our ends.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Ralph Buttigieg on 05/14/2011 10:36 pm
G'day,

Regarding the risk and the worth of the project.

It depends are people being sent or people deciding to go?

There are two type of explorers, contract and private.

Contract explorers are what current professional astronauts are. An organisation such as NASA has a mission for them then send them out. They are hired employees. That means NASA has certain responsibilities regarding their safety and the success of the project. They can not afford to send anyone unless they are sure of a very high success rate. My understanding is that American OH&S regulation wouldn't allow human Mars missions because of the radiation risk alone.

 Private exploration is a different matter. There successful explorers assess the risk and take counter measures to reduce them to a level which *they* find acceptable. Then they go. Think of Frenchwoman Raphaela Le Gouvello who has crossed by wind surf the Atlantic, Pacific and Indian Oceans  or the two Aussie lads who Kayaked the Tasman.

The great think about the Zubrin/Dragon mission is that it reduce costs to a level were jut maybe private mission could be done. At the very least it brings that day closer.

ta

Ralph
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: pathfinder_01 on 05/14/2011 10:44 pm
Private exploration is a different matter. There successful explorers assess the risk and take counter measures to reduce them to a level which *they* find acceptable. Then they go. Think of Frenchwoman Raphaela Le Gouvello who has crossed by wind surf the Atlantic, Pacific and Indian Oceans  or the two Aussie lads who Kayaked the Tasman.

The great think about the Zubrin/Dragon mission is that it reduce costs to a level were jut maybe private mission could be done. At the very least it brings that day closer.

ta

Ralph

Yeap that is one benefit to commercial space. It enables this kind of thing.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: HIP2BSQRE on 05/14/2011 11:48 pm
Before this dissolves into a debate of technology.. and I thoroughly admit to having started that debate.. I have to say I would much rather hear people's opinions on the quotes.  Zubrin doesn't get up on stage or write for the newspapers to convince the technical audience.  In fact, I'm not terribly sure I've ever heard Zubrin say much to convince the technical audience. 

As I see it, his argument is simple: risk to astronaut life, be it immediate mission failure risk or long term health risk, is worth it to go to Mars.. and he typically goes on to say that the possibility of finding life is the best reason to go to Mars, with eventual colonization being a distant second.

How do you feel about that?  Is his "right stuff" mentality correct?  Is NASA way too cautious these days?  Or is he just shouting into the wind?

(for anyone who cares, my personal belief is that NASA will never do another mission with the level of risk of Apollo 8.. and their biggest fear is that another set of astronauts will some day die and the entirety of HSF will be shut down.  Whether or not you think that is good or bad is irrelevant, it's the way it is, deal with it.)


NASA is risk adverse.  But guess what--the West would not be won if we were risk adverse.  People climb mountain--everest.  How many die each year???
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Adaptation on 05/15/2011 06:42 am
Your array would loose 5% of it's total capability every 3 weeks.

brb calling Hubble team to find out how they still get pictures with the infinitesimal amount of power they have after considering radiation decay.

  Take that over two 6 month trips.  Figure out your power need, then work backwards and double it in case circuits are broken in between cells. 

Yep hayabusa sure lost half its power from broken circuits.

Let us do the math.  I will assume that this is a low-capacity 2-person mars mission, with a Dragon and an Almaz-sized/capability module with a propultion system which is chemical, not electric in order to reduce the power demands.  Almaz consumed 8500W/h, and Dragon's demands appear to be closer to 1500W/h, so let us get an aim-point of 10kW total demand after 12 months of exposure to solar radiation.

Holy donuts batman Almaz needed just 8500 watt hours of energy to run for a year.  Forget solar all together I can get that in about 500 lbs of lead acid batteries. 

  What has been found is, per solar incident, solar panels decay at the rate of 2%.  During active periods (and we're entering into one right now), there are between 200-250 of these incidents per year.  So, let us calculate, 10kW, growing by 2% each time over 250 times, gives us  1484.13 kW.  Doubling that, we will need roughly 3MW of power in order to guarantee survival for return.
I thought you already mentioned this as the radiation decay of 5% per three weeks.  Also didn't we double because of all the circuit that will be destroyed from space magic. 

Each panel of the ISS generates 246kW of power, so we would need 6 of them to guarantee power supply.  When you take this with the weight of the panels, four of them with the truss needed to support them at 14mT.  Adding 50% more would result in 21mT.
Yeay ten year old tech getting 20 W/kg that must be the pinnacle of solar development... Just checked, you can get arrays around ten times the power density of that these days.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: rklaehn on 05/15/2011 07:38 am
What has been found is, per solar incident, solar panels decay at the rate of 2%.  During active periods (and we're entering into one right now), there are between 200-250 of these incidents per year.  So, let us calculate, 10kW, growing by 2% each time over 250 times, gives us  1484.13 kW.  Doubling that, we will need roughly 3MW of power in order to guarantee survival for return.  Each panel of the ISS generates 246kW of power, so we would need 6 of them to guarantee power supply.  When you take this with the weight of the panels, four of them with the truss needed to support them at 14mT.  Adding 50% more would result in 21mT.

These numbers do not make any sense. GEO comsats are mostly outside the earth magnetic field, so they get the full brunt of all "solar events". Yet they manage with a loss of power of <30% over the typical lifetime of 15 years. If you use the same kind of cells on a mars mission, your power loss due to radiation would be almost negible for a 900 day mars mission.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: docmordrid on 05/15/2011 08:17 am
Just what kind of solar cells are we talking about here?

Different types of solar cells have different degrees of radiation hardness,  and some newer types are pretty darned hard vs. older ones. p-n? Ga nitride? InGa nitride? InGaP/GaAs/Ge triple-junction? ???? 

Without specifying solar cell type comparing satellite A to space station B or telescope C isn't very helpful.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Nathan on 05/15/2011 08:48 am
Zubrin is preparing to talk in deal on this subject on 22nd according to the mars society website so we will get details then.
I expect the landing system will use supersonic retro propulsion.
The mission is less risky is a complete set of vehicle copies are sent ahead.
Zubrin is the most innovative and inspirational thinker on the subject of mars - out thinking NASA consistently. Case for mars laid out the first realistic method of running a mars program. I respect the man. I look forward to hearing the details of this architecture.

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: QuantumG on 05/15/2011 08:54 am
Don't be too disappointed if the "details" are nothing more than hobbyist level analysis that you might read on someone's blog *cough*.

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: alexw on 05/15/2011 09:27 am
What's a "W/h" intended to mean?
Watt/hour.  Basic electricity term to determine power demand.
I think you mean Watt-hour (W·h).  Power divided by time doesn't make much sense. Power multiplied by time on the other hand is a measure of energy, which I assume is what you're thinking of.
    Indeed. I'm afraid it's a case of "You keep using that word. I do not think it means what you think it means."

     Actually, it is mildly amusing to try to think of situations where W/h -- some form of power acceleration -- would be a sensible unit. Perhaps the slow ramping up of (say) a hydroelectric dam to meet shifting grid demand.

     -Alex
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: alexw on 05/15/2011 09:36 am
What has been found is, per solar incident, solar panels decay at the rate of 2%.  During active periods (and we're entering into one right now), there are between 200-250 of these incidents per year.  So, let us calculate, 10kW, growing by 2% each time over 250 times, gives us  1484.13 kW.  Doubling that, we will need roughly 3MW of power in order to guarantee survival for return.  Each panel of the ISS generates 246kW of power, so we would need 6 of them to guarantee power supply.  When you take this with the weight of the panels, four of them with the truss needed to support them at 14mT.  Adding 50% more would result in 21mT.
These numbers do not make any sense. GEO comsats are mostly outside the earth magnetic field, so they get the full brunt of all "solar events". Yet they manage with a loss of power of <30% over the typical lifetime of 15 years. If you use the same kind of cells on a mars mission, your power loss due to radiation would be almost negible for a 900 day mars mission.
   Yeah. 0.98^250 = 0.0064. Surely existing Mars orbiters are not down to much less than 1% of their rated power. How much worse for poor MESSENGER?
    -Alex
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: A_M_Swallow on 05/15/2011 10:38 am
{snip}
     Actually, it is mildly amusing to try to think of situations where W/h -- some form of power acceleration -- would be a sensible unit. Perhaps the slow ramping up of (say) a hydroelectric dam to meet shifting grid demand.

The power output of solar power stations changes throughout the day as the angle to the sun changes.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: A_M_Swallow on 05/15/2011 10:41 am
Just what kind of solar cells are we talking about here?

Different types of solar cells have different degrees of radiation hardness,  and some newer types are pretty darned hard vs. older ones. p-n? Ga nitride? InGa nitride? InGaP/GaAs/Ge triple-junction? ???? 

Without specifying solar cell type comparing satellite A to space station B or telescope C isn't very helpful.

Solar cells do not have a monopoly on generating electricity from sun light.  Mirrors concentrating light onto Stirling engines can also be used.  Solar dynamic systems are intrinsically radiation hard.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: sanman on 05/15/2011 12:12 pm
Why do we have to rush to send a man, if we can just send better robots that could learn the same stuff more cheaply?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Nathan on 05/15/2011 12:13 pm
Don't be too disappointed if the "details" are nothing more than hobbyist level analysis that you might read on someone's blog *cough*.


NASA can't even get to that level. I have a great deal of respect for the man and his passion for the cause.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: QuantumG on 05/15/2011 12:15 pm
Why do we have to rush to send a man, if we can just send better robots that could learn the same stuff more cheaply?

There's at least two other threads going with that topic, please don't add to it here.

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: pathfinder_01 on 05/15/2011 02:18 pm
Don't be too disappointed if the "details" are nothing more than hobbyist level analysis that you might read on someone's blog *cough*.


NASA can't even get to that level. I have a great deal of respect for the man and his passion for the cause.

That is becuase there hasn't been enough development to see what is and is not possible and what is and is not needed.  FH may lower the price to space but it can't fix the technology issuses.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: majormajor42 on 05/15/2011 02:28 pm
"Zubrin's" Falcon Heavy Mars Mission  ???

Musk risks his personal fortune and millions of NASA/taxpayer $$$
We triumphantly land on Mars.
Zubrin: "You're welcome"
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: RocketEconomist327 on 05/15/2011 03:55 pm
"Zubrin's" Falcon Heavy Mars Mission  ???

Musk risks his personal fortune and millions of NASA/taxpayer $$$
We triumphantly land on Mars.
Zubrin: "You're welcome"

In comparison to the 11.1 Billion we wasted on Constellation or the 10 billion more we waste on the Senate Launch System, we are getting new capability and it is an acceptable risk.  Even if Musk was 10 years late it would still be better than the poppycock we are getting from NASA and congress.

VR
TPIS
RE327

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Downix on 05/15/2011 04:51 pm
Your array would loose 5% of it's total capability every 3 weeks.

brb calling Hubble team to find out how they still get pictures with the infinitesimal amount of power they have after considering radiation decay.
Hubble is still within the earths magnetic influence, hence is shielded from the majority of the degredation.  But even then, it still is loosing power, slowly.
Quote
  Take that over two 6 month trips.  Figure out your power need, then work backwards and double it in case circuits are broken in between cells. 

Yep hayabusa sure lost half its power from broken circuits.
Hayabusa's power losses were greater than they anticipated, which is why it's arrival at Itokawa was delayed by months, lack of power for it's electrical thrusters. I actually used Hayabusa's power loss as one of the baselines to calculate out the rate of decay for extra-orbital panels.  And this was during a low point in solar activity.
Quote
Let us do the math.  I will assume that this is a low-capacity 2-person mars mission, with a Dragon and an Almaz-sized/capability module with a propultion system which is chemical, not electric in order to reduce the power demands.  Almaz consumed 8500W/h, and Dragon's demands appear to be closer to 1500W/h, so let us get an aim-point of 10kW total demand after 12 months of exposure to solar radiation.

Holy donuts batman Almaz needed just 8500 watt hours of energy to run for a year.  Forget solar all together I can get that in about 500 lbs of lead acid batteries. 
As I put it as 8500 Watts per hour, I can only assume there is some ulterior motivation at work here.
Quote
  What has been found is, per solar incident, solar panels decay at the rate of 2%.  During active periods (and we're entering into one right now), there are between 200-250 of these incidents per year.  So, let us calculate, 10kW, growing by 2% each time over 250 times, gives us  1484.13 kW.  Doubling that, we will need roughly 3MW of power in order to guarantee survival for return.
I thought you already mentioned this as the radiation decay of 5% per three weeks.  Also didn't we double because of all the circuit that will be destroyed from space magic. 
Have you ever built an electric circuit before?
Quote
Each panel of the ISS generates 246kW of power, so we would need 6 of them to guarantee power supply.  When you take this with the weight of the panels, four of them with the truss needed to support them at 14mT.  Adding 50% more would result in 21mT.
Yeay ten year old tech getting 20 W/kg that must be the pinnacle of solar development... Just checked, you can get arrays around ten times the power density of that these days.
Well, if you want it floating out there without any support structure, wiring, or framework, go right ahead.  I prefer dealing with real world scenarios, where you need to hold something in place. 
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Downix on 05/15/2011 04:54 pm
Just what kind of solar cells are we talking about here?

Different types of solar cells have different degrees of radiation hardness,  and some newer types are pretty darned hard vs. older ones. p-n? Ga nitride? InGa nitride? InGaP/GaAs/Ge triple-junction? ???? 

Without specifying solar cell type comparing satellite A to space station B or telescope C isn't very helpful.
Indeed.  For simplicities sake I was using the ISS's panels.  If we were to discuss this seriously, first we'd need someone to discuss it with who is willing to hold an honest discussion and not just "SpaceX IZ GOD!!!" or some such nonsense.  We're not going to Mars in a Dragon capsule, nor in an Orion capsule.  We are going in a spaceship, which either one of these may attach to for crew access.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: ugordan on 05/15/2011 05:01 pm
Hubble is still within the earths magnetic influence, hence is shielded from the majority of the degredation.  But even then, it still is loosing power, slowly.

Again, what about GEO comsats as already pointed out? The solar degradation rates you talk of just don't pass the sniff test. You bring up Hayabusa, but don't mention the plethora of other interplanetary craft that suffered no such severe degradation due to solar flares.

Quote
As I put it as 8500 Watts per hour, I can only assume there is some ulterior motivation at work here.

There's no ulterior motivation here. Watts per hour is a meaningless unit. Have your ever heard one talk about horsepowers per hour? Spacecraft power requirements are expressed in watts.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Downix on 05/15/2011 05:43 pm
Hubble is still within the earths magnetic influence, hence is shielded from the majority of the degredation.  But even then, it still is loosing power, slowly.

Again, what about GEO comsats as already pointed out? The solar degradation rates you talk of just don't pass the sniff test. You bring up Hayabusa, but don't mention the plethora of other interplanetary craft that suffered no such severe degradation due to solar flares.
I actually can't name any which did not suffer degradation.  The Solar Heliospheric Observatory lost 2% of it's solar generative ability in one day, for instance, from the solar event of Nov 4, 2001, with a total power loss of 8% from June to Dec 2001.  A paper from the University of Moscow titled "Analysis of Geostationary Spacecraft Solar Arrays Degradation" did a detailed study of GEO comstats, and found that they also suffer from the same issue.  They found several things.  One, the newer, lighter panels degraded faster than the older, due to more density of the solar array.  Two, that a GEO satellite is bombarded with enough radiation to cause a 7% loss of power within it's first 6 months of operation.  They also discussed how a GEO is mostly outside of the magnetic influence of the earth, but not completely so still does have some protection.
Quote
Quote
As I put it as 8500 Watts per hour, I can only assume there is some ulterior motivation at work here.

There's no ulterior motivation here. Watts per hour is a meaningless unit. Have your ever heard one talk about horsepowers per hour? Spacecraft power requirements are expressed in watts.
Computer electronics are rated in watts per hour, solar panels are also rated in watts per hour.  Why are spacecraft exempt from this accepted EE system?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Zubrin on 05/15/2011 05:52 pm
Friends;
I apologize for not being able to include all the details of the proposed mission plan in my WSJ op ed, which had a 1000 word limit.

In answer to some of the objections raised in this forum, you may note the following:

1. There is no need for zero gravity exposure. Artificial gravity can be provided to the crew by tethering the Dragon off the TMI stage, in the same way as is recommended in the baseline Mars Direct plan.

2. Cosmic ray radiation exposure for the crew is precisely THE SAME as that which would be received by those on any other credible Mars mission, all of which would use the 6 month Conjunction class trajectory to Mars, both because that is the point of diminishing returns (the "knee of the curve") where delta-V trades off against trip time, and because it is uniquely the trajectory that provides a 2-year free return orbit after launch from Earth. Assuming the baseline mission, the total cosmic ray dose would be no greater than that already received by a half dozen cosmonauts and astronauts who participated in long duration missions on Mir or ISS, with no radiation induced health effects having been reported. (Cosmic ray dose rates on ISS are 50% those of interplanetary space. The Earth's magnetic field does not shield effectively against cosmic rays. In fact, with a crew of 6, the current planned ISS program will inflict the equivalent of 30 man-years of interplanetary travel GCR doses on its crews over the next decade. This is an order of magnitude more than that which will be received by the crew of the mission proposed here. ) There are enough consumables on board to provide shielding against solar flares.

3. The preferred method of Mars capture is aerocapture, rather than direct entry. This means that the Dragon aeroshield, which has some lifting capability, may well be adequate. To see this with a back of the envelope calculation, consider a loaded Dragon system with an entry mass of 17000 kg, an effective shield diameter of 4 meters, a drag coeffecient of 1, coming in with an entry velocity of 6 km/s at an altitude of 33 km, where the Mars atmospheric density is 0.8 gm/m3. Setting drag equal to mass times deceleration, you can see that the system would decelerate at a speed of 42 m/s2, or a little over 4 gs. It could thus perform a 1 km/s deceleration in about 25 seconds, during which time it would travel about 140 km. This deceleration is sufficient to capture the spacecraft from an interplanetary trajectory into a loosely bound highly elliptical orbit around Mars. If the perigee is not raised, the craft will reenter again, and again, progressively lowering the apogee of its orbit, until either a desired apogee for orbital operations is achieved or the craft is committed to entry for purposes of landing. That said, if a larger aerobrake were desired, this could be created by adding either a flex-fabric or inflatable skirt to the Dragon core shield.

4. The habitable volume is admittedly lower than optimal. However it should be noted that with 5 cubic meters per crew member, it is 2.5 times higher than the 2 cubic meters per crew member possessed by Apollo crews. It could be expanded in space by the use of inflatable add-on modules. Extra space could be provided on the ground by using a 4th launch to preland another Dragon loaded with supplies, including one or more inflatable modules which could be set up by the crew after they land.

5. The mission architecture is much safer than any based on complex mega systems requiring orbital assembly, since the quality control of orbital assembly does not compare with that which can be accomplished on the ground. It would be better to have a crew of 4, but if we are to do it with Falcon 9 heavy's,  a crew of 2 is all we can do, and while it lacks a degree of redundancy otherwise desirable, it offers the counter benefit of putting the fewest number of people at risk on the first mission. It's quite true that not flying anywhere at all would be safer, but if you want to get to Mars, you have to go to Mars.

Robert




Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: ugordan on 05/15/2011 05:53 pm
There's no ulterior motivation here. Watts per hour is a meaningless unit. Have your ever heard one talk about horsepowers per hour? Spacecraft power requirements are expressed in watts.
Computer electronics are rated in watts per hour, solar panels are also rated in watts per hour.

What characteristic of theirs is rated in watts per hour?

http://en.wikipedia.org/wiki/Watt#Confusion_of_watts.2C_watt-hours.2C_and_watts_per_hour
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Downix on 05/15/2011 05:58 pm
There's no ulterior motivation here. Watts per hour is a meaningless unit. Have your ever heard one talk about horsepowers per hour? Spacecraft power requirements are expressed in watts.
Computer electronics are rated in watts per hour, solar panels are also rated in watts per hour.

What characteristic of theirs is rated in watts per hour?

http://en.wikipedia.org/wiki/Watt#Confusion_of_watts.2C_watt-hours.2C_and_watts_per_hour
Proof to me to not reply before my first cup of coffee.  I meant Watt-hours.  Stubborn me for not waiting.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Downix on 05/15/2011 06:03 pm
Friends;
I apologize for not being able to include all the details of the proposed mission plan in my WSJ op ed, which had a 1000 word limit.

Fully understandable
Quote
In answer to some of the objections raised in this forum, you may note the following:

1. There is no need for zero gravity exposure. Artificial gravity can be provided to the crew by tethering the Dragon off the TMI stage, in the same way as is recommended in the baseline Mars Direct plan.
That is one way to do it, of course.  And for cheap-direct, it's a good one.
Quote
2. Cosmic ray radiation exposure for the crew is precisely THE SAME as that which would be received by those on any other credible Mars mission, all of which would use the 6 month Conjunction class trajectory to Mars, both because that is the point of diminishing returns (the "knee of the curve") where delta-V trades off against trip time, and because it is uniquely the trajectory that provides a 2-year free return orbit after launch from Earth. Assuming the baseline mission, the total cosmic ray dose would be no greater than that already received by a half dozen cosmonauts and astronauts who participated in long duration missions on Mir or ISS, with no radiation induced health effects having been reported. (Cosmic ray dose rates on ISS are 50% those of interplanetary space. The Earth's magnetic field does not shield effectively against cosmic rays. In fact, with a crew of 6, the current planned ISS program will inflict the equivalent of 30 man-years of interplanetary travel GCR doses on its crews over the next decade. This is an order of magnitude more than that which will be received by the crew of the mission proposed here. ) There are enough consumables on board to provide shielding against solar flares.
Wasn't that worried about human radiation exposure.  My concern was more on the solar panels, if they are used.  Personally I'd sooner use a 100kW MSTR or MLUR and skip the whole problem.
Quote
3. The preferred method of Mars capture is aerocapture, rather than direct entry. This means that the Dragon aeroshield, which has some lifting capability, may well be adequate. To see this with a back of the envelope calculation, consider a loaded Dragon system with an entry mass of 17000 kg, an effective shield diameter of 4 meters, a drag coeffecient of 1, coming in with an entry velocity of 6 km/s at an altitude of 33 km, where the Mars atmospheric density is 0.8 gm/m3. Setting drag equal to mass times deceleration, you can see that the system would decelerate at a speed of 42 m/s2, or a little over 4 gs. It could thus perform a 1 km/s deceleration in about 25 seconds, during which time it would travel about 140 km. This deceleration is sufficient to capture the spacecraft from an interplanetary trajectory into a loosely bound highly elliptical orbit around Mars. If the perigee is not raised, the craft will reenter again, and again, progressively lowering the apogee of its orbit, until either a desired apogee for orbital operations is achieved or the craft is committed to entry for purposes of landing. That said, if a larger aerobrake were desired, this could be created by adding either a flex-fabric or inflatable skirt to the Dragon core shield.
Simple solution indeed.
Quote
4. The habitable volume is admittedly lower than optimal. However it should be noted that with 5 cubic meters per crew member, it is 2.5 times higher than the 2 cubic meters per crew member possessed by Apollo crews. It could be expanded in space by the use of inflatable add-on modules. Extra space could be provided on the ground by using a 4th launch to preland another Dragon loaded with supplies, including one or more inflatable modules which could be set up by the crew after they land.
That is an approach I always appreciate, pre-landing your supply needs.
Quote
5. The mission architecture is much safer than any based on complex mega systems requiring orbital assembly, since the quality control of orbital assembly does not compare with that which can be accomplished on the ground. It would be better to have a crew of 4, but if we are to do it with Falcon 9 heavy's,  a crew of 2 is all we can do, and while it lacks a degree of redundancy otherwise desirable, it offers the counter benefit of putting the fewest number of people at risk on the first mission. It's quite true that not flying anywhere at all would be safer, but if you want to get to Mars, you have to go to Mars.

Robert
Orbital Assembly is not a game-stopper, however.  Alternatively, you could pull a Skylab, and utilize the fuel tanks as living space from your departure stage, giving you the extra room you need.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Zubrin on 05/15/2011 08:05 pm
Friends;
Please see my answer to some of the issues raised on page 5 of this thread.
Thanks.
Robert


http://on.wsj.com/mNABsj  (note that you may have to play "google the headline" to read this)

My summary:

Flight 1. Falcon Heavy puts Earth Return Vehicle into Mars orbit.
Flight 2. Falcon Heavy puts Mars Ascent Vehicle on Mars surface.
Flight 3. Falcon Heavy sends Crew Transfer Vehicle to Mars to precise landing.
Crew spends 500 days on the surface, uses the MAV to ascend to the ERV and return to an ocean landing.

The ERV has a LOX/Kero engine, presumably preloaded with kero only.

The MAV has a LOX/Methane engine and a chemical reactor to make oxygen from the Mars atmosphere (note that Zubrin isn't advocating making Methane on the surface.. presumably to keep the power requirements under 10 kW).

The CTV has maneuvering thrusters only and carries 2500 kg of provisions for a crew of two for 3 years.  There's no discussion of artificial gravity.

All three vehicles are Dragon derived.

Choice quotes:

   "we could send expeditions to Mars at half the cost to launch a Space Shuttle flight."

  "There is no question that this plan involves considerable risk, and a variety of missions, technology developments and testing programs in advance might reduce that risk. But if we try to do even a significant fraction before committing to the mission, we will never get to Mars.  [..] If we want to reduce risk to human life, there are vastly more effective ways of doing so than by spending $10 billion per year for the next two or three decades on a human spaceflight program mired in low Earth orbit."

I think the only more extreme position I've ever read is one-way-to-stay.

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Cog_in_the_machine on 05/15/2011 08:28 pm
Considering a previous remark made by Quantum in the Nautilus thread, I like where this is going.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: DaveH62 on 05/15/2011 08:29 pm
Private exploration is a different matter. There successful explorers assess the risk and take counter measures to reduce them to a level which *they* find acceptable. Then they go. Think of Frenchwoman Raphaela Le Gouvello who has crossed by wind surf the Atlantic, Pacific and Indian Oceans  or the two Aussie lads who Kayaked the Tasman.

The great think about the Zubrin/Dragon mission is that it reduce costs to a level were jut maybe private mission could be done. At the very least it brings that day closer.

ta

Ralph

Yeap that is one benefit to commercial space. It enables this kind of thing.

I think the private exploration element needs more discussion. What would the cost of a Amundsen/Scott type of exploration program to Mars. Is our technology baseline high enough to make the risk comparable to those Antarctic missions from the last century? Are there similar explorers today to risk life and fortune to expand the human frontier. NASA will likely require another 40 years to get to Mars with their collective risk aversion (Congressional and media oversight, changing priorities, changing presidents...). This could change if China challenges us and we choose to respond, but based on our current funding and support culture at NASA, it is difficult to see a human mission before the 2030's at best.
The only way for us to get to Mars in my lifetime is for a President to commit to it, and be willing to spend about 10 times the real mission cost, or private exploration. Would Paul Allen or someone be willing to spend $500 million to sponsor a mission? Branson has his money tied up in Virgin Space, or he would be a logical rich guy willing to risk his life guy. Could it be done for less than a billion? I see a lot of engineering math, but less financial math, and the more difficult to quantify math about personal risk. I know Musk wants to do this, but can he afford this without some big third party funding?
How little could a private mission be done with? Keep in mind, once an initial private mission is completed, more missions will follow and risks once defined empirically, can be better understood by politicians and our larger society.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: sdsds on 05/15/2011 08:45 pm
And that's the fundamental disconnect.. Zubrin wants to get going already and the other camp wants to build the space equivalent of a Winnebago.

I doubt the implication underlying "the other camp."  There are not only two camps.  For example, I consider myself in the "aggressive flexible path" camp.  How does that fit into the implied dichotomy?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: DLR on 05/15/2011 08:51 pm
Interesting plan, albeit pretty limited capability-wise.

IMO adding a few more Falcon launches to add further redundancy/capability (for example by pre-positioning assets in Mars orbit and on the surface) or the addition of a high-energy upper stage to the Falcon Heavy to increase its trans-Mars throw mass will probably be necessary to make the plan "fly" politically (reducing risk), or if you want more than just a flags/footprints mission with two astronauts and a Dragon on Mars.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Adaptation on 05/15/2011 08:57 pm
Zubrin I kinda like the new approach, good job and good luck with it.  I have always felt that radiation concerns about spaceflight where created by the man to keep us down.  Tether based artificial gravity has not really been worked on since Gemini and they had some problems with it, I know TMS had a cube sat they were working on to test it out but I haven't heard anything about it after newmars disappeared.  I really hope you can cut costs low enough that you can find a Warren Buffett to bankroll the mission.  I wonder if you would be willing to combine the first and second launch by using an array of hall effect thrusters to get to mars instead of chemical rockets.  You could have 10-20kW of the solar fold back up and reuse it on the surface, I like to pretend that I know how to come up with cool stuff (^_^) 
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: MikeAtkinson on 05/15/2011 09:24 pm
Friends;
I apologize for not being able to include all the details of the proposed mission plan in my WSJ op ed, which had a 1000 word limit.

In answer to some of the objections raised in this forum, you may note the following:

1. There is no need for zero gravity exposure. Artificial gravity can be provided to the crew by tethering the Dragon off the TMI stage, in the same way as is recommended in the baseline Mars Direct plan.

Agreed, but I think you have not allocated enough mass for spin-up/down, tether & related systems.

2. Cosmic ray radiation exposure for the crew is precisely THE SAME as that which would be received by those on any other credible Mars mission, all of which would use the 6 month Conjunction class trajectory to Mars, both because that is the point of diminishing returns (the "knee of the curve") where delta-V trades off against trip time, and because it is uniquely the trajectory that provides a 2-year free return orbit after launch from Earth. Assuming the baseline mission, the total cosmic ray dose would be no greater than that already received by a half dozen cosmonauts and astronauts who participated in long duration missions on Mir or ISS, with no radiation induced health effects having been reported. (Cosmic ray dose rates on ISS are 50% those of interplanetary space. The Earth's magnetic field does not shield effectively against cosmic rays. In fact, with a crew of 6, the current planned ISS program will inflict the equivalent of 30 man-years of interplanetary travel GCR doses on its crews over the next decade. This is an order of magnitude more than that which will be received by the crew of the mission proposed here. ) There are enough consumables on board to provide shielding against solar flares.

Agreed, radiation is no worse than for most other mission architectures I've seen.

3. The preferred method of Mars capture is aerocapture, rather than direct entry. This means that the Dragon aeroshield, which has some lifting capability, may well be adequate. To see this with a back of the envelope calculation, consider a loaded Dragon system with an entry mass of 17000 kg, an effective shield diameter of 4 meters, a drag coeffecient of 1, coming in with an entry velocity of 6 km/s at an altitude of 33 km, where the Mars atmospheric density is 0.8 gm/m3. Setting drag equal to mass times deceleration, you can see that the system would decelerate at a speed of 42 m/s2, or a little over 4 gs. It could thus perform a 1 km/s deceleration in about 25 seconds, during which time it would travel about 140 km. This deceleration is sufficient to capture the spacecraft from an interplanetary trajectory into a loosely bound highly elliptical orbit around Mars. If the perigee is not raised, the craft will reenter again, and again, progressively lowering the apogee of its orbit, until either a desired apogee for orbital operations is achieved or the craft is committed to entry for purposes of landing. That said, if a larger aerobrake were desired, this could be created by adding either a flex-fabric or inflatable skirt to the Dragon core shield.

Agree that aero-capture into Mars orbit is the best solution and seems possible for Dragon.

I am worried however about EDL, a heatshield of the size of Dragon is not sufficient to slow the mass of Dragon enough to deploy parachutes, there does not seem to be enough mass allocated for propulsive descent.

I'm also worried about landing the Mars Ascent Stage and its fuel and O2 manufacturing kit.

You seem to be assuming that it is possible to land about 12 tonnes of useful payload from an initial mass in Mars orbit of 17 tonnes. That is not possible with any EDL system that I have heard of.

4. The habitable volume is admittedly lower than optimal. However it should be noted that with 5 cubic meters per crew member, it is 2.5 times higher than the 2 cubic meters per crew member possessed by Apollo crews. It could be expanded in space by the use of inflatable add-on modules. Extra space could be provided on the ground by using a 4th launch to preland another Dragon loaded with supplies, including one or more inflatable modules which could be set up by the crew after they land.

The 10m^3 of Dragon would need to hold 2.5 tonne of supplies (assume at least 3m^3 with packaging), air and water recycling systems, even assuming 100% efficiency a buffer supply of water and gas, spare clothing, tools, equipment, Mars suits (+ space suits?). I would be surprised if there were more than 4 m^3 available for crew use

5. The mission architecture is much safer than any based on complex mega systems requiring orbital assembly, since the quality control of orbital assembly does not compare with that which can be accomplished on the ground. It would be better to have a crew of 4, but if we are to do it with Falcon 9 heavy's,  a crew of 2 is all we can do, and while it lacks a degree of redundancy otherwise desirable, it offers the counter benefit of putting the fewest number of people at risk on the first mission. It's quite true that not flying anywhere at all would be safer, but if you want to get to Mars, you have to go to Mars.

Using a rendezvous of a 53 tonne EDS with Earth integrated payload (2 FH launches, for 6 in total) or an empty EDS + payload launched on a single FH and refuelled at a propellant depot seem better options. That would allow enough payload mass for a reasonable hab volume, 3+ crew, EDL and extra margins all round.


Robert
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Nathan on 05/15/2011 09:34 pm
Thank you Robert. The falcon 9 heavy does provide an excellent means of enabling a mars mission at last. The specifics of the architecture would obviously depend on whom is paying.

In the architecture proposed, how is edl handled by dragon? Inflatables or supersonic retro propulsion? Or other means?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: mlorrey on 05/15/2011 11:54 pm

Computer electronics are rated in watts per hour, solar panels are also rated in watts per hour.  Why are spacecraft exempt from this accepted EE system?

Because electronics are NOT rated in watts per hour, they are rated in watt*hours. Multiplication, not division.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Zubrin on 05/15/2011 11:55 pm
Friends;
Here are further answers relating to concerns that have been advanced.

1. Habitable volume.
As noted, if the Dragon capsule alone is used, this provides 5 m3 living volume per crew member, which compares to 2 m3 per crew on an Apollo capsule, 9 m3 per crew member on the Space Shuttle, or 8 m3 per crew member on a German U-Boat (Type VII, the fleet workhorse) during WWII. This would be uncomfortable, but ultimately, workable by a truly dedicated crew. However these limits can be transcended. The Dragon has a 14m3 cargo area hold below the aeroshield. Into this we could pack an inflatable hab module, in deflated form, but which if inflated, could be as much as 8 m in diameter and perhaps 10 m long, thereby providing 3 decks, with added volume of 502 m3 and a total floor space equal to 1.5 times as much as that in the Mars Society's MDRS or FMARS stations, which have proved adequate in size for crews of 6. After Trans Mars injection, the Dragon would pull away from the cargo section and turn around, then return to mate its docking hatch with one in the inflatable. It would then pull the inflatable out of the cargo hold, much as the Apollo command module pulled out the LEM. The inflatable could then be inflated. The other end of the inflatable would be attached to the tether, which is connected to the TMI stage, for use in creating artificial gravity.
Upon reaching Mars the inflatable could either be expended, along with the tether system and TMI stage, prior to aerocapture. Alternatively, and optimally, the tether and TMI stage alone would be expended, but the inflatable deflated and retained for redeployment as a ground hab after landing.

2. EDL
Using just its aeroshield for deceleration, the Dragon would have a terminal velocity of around 340 m/s on Mars at low altitude (air density 16 gm/m3). So we could either give it a rocket delta-V capability of 600 m/s (a 20% mass hit assuming storable or RP/O2 propulsion, Isp~330 s) to land all propulsive, or we could use a drogue to slow it down (a 20 m diameter chute would slow it to ~70 m/s) and then employ a much smaller rocket delta-V for landing.

Robert
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: A_M_Swallow on 05/16/2011 12:01 am
There is an outward journey, stay on Mars and a return journey.  Is there any sort of habitat for the return journey?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: QuantumG on 05/16/2011 12:30 am
Hey Bob, great to hear from you again.

So it seems the flight surgeons are starting to come to a consensus that Mars gravity will be no better than zero-g for bone/muscle loss.  I think they are premature (they have about one data point) but they're begging for some artificial gravity experiments now, be they with rats or humans.

Would you support a capsule-tether-counterweight test program with the goal of evaluating the gravity prescription?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: scienceguy on 05/16/2011 01:53 am
Hi Robert Zubrin,

I just wanted to say that I'm a big fan. Your book "The Case for Mars" really inspired me. I have also read "Mars on Earth".

I work in an academic library so I have access to all kinds of scientific monographs and journals. I have been researching aspects of space travel in hopes that I may one day be able to help out somehow.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Comga on 05/16/2011 03:33 am
... After Trans Mars injection, the Dragon would pull away from the cargo section and turn around, then return to mate its docking hatch with one in the inflatable. It would then pull the inflatable out of the cargo hold, much as the Apollo command module pulled out the LEM. ...

An issue with that method is that the cargo section would need an independent ACS, like the third stage of the Saturn V, so that both are controlled for docking.  An alternative has been proposed by the Japanese, where the two remain attached.  Their scheme has two arms from the Service/ Propulsion Module behind the Descent Module capsule to the Orbital Module.  The arms lengthen, swing around to put the OM in front of the DM, and then contract and berth them, which is much simpler than docking.  The arms provide no support during launch, and so do not need substantial strength.  They could be light and simple.

It is discussed and illustrated  here. (http://forum.nasaspaceflight.com/index.php?topic=19061.msg489038#msg489038)
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: MATTBLAK on 05/16/2011 07:08 am
Friends;
Here are further answers relating to concerns that have been advanced.

1. Habitable volume.
As noted, if the Dragon capsule alone is used, this provides 5 m3 living volume per crew member, which compares to 2 m3 per crew on an Apollo capsule, 9 m3 per crew member on the Space Shuttle, or 8 m3 per crew member on a German U-Boat (Type VII, the fleet workhorse) during WWII. This would be uncomfortable, but ultimately, workable by a truly dedicated crew. However these limits can be transcended. The Dragon has a 14m3 cargo area hold below the aeroshield. Into this we could pack an inflatable hab module, in deflated form, but which if inflated, could be as much as 8 m in diameter and perhaps 10 m long, thereby providing 3 decks, with added volume of 502 m3 and a total floor space equal to 1.5 times as much as that in the Mars Society's MDRS or FMARS stations, which have proved adequate in size for crews of 6. After Trans Mars injection, the Dragon would pull away from the cargo section and turn around, then return to mate its docking hatch with one in the inflatable. It would then pull the inflatable out of the cargo hold, much as the Apollo command module pulled out the LEM. The inflatable could then be inflated. The other end of the inflatable would be attached to the tether, which is connected to the TMI stage, for use in creating artificial gravity.
Upon reaching Mars the inflatable could either be expended, along with the tether system and TMI stage, prior to aerocapture. Alternatively, and optimally, the tether and TMI stage alone would be expended, but the inflatable deflated and retained for redeployment as a ground hab after landing.

2. EDL
Using just its aeroshield for deceleration, the Dragon would have a terminal velocity of around 340 m/s on Mars at low altitude (air density 16 gm/m3). So we could either give it a rocket delta-V capability of 600 m/s (a 20% mass hit assuming storable or RP/O2 propulsion, Isp~330 s) to land all propulsive, or we could use a drogue to slow it down (a 20 m diameter chute would slow it to ~70 m/s) and then employ a much smaller rocket delta-V for landing.

Robert

Hello Dr Zubrin! Thanks for slaying some of the 'Dragons of doubt', er so to speak.

As I mentioned in an early post in this thread - we seem to be in agreement about the Dragon doing a 'Transposition & Docking' manuever to join with the Trans-Mars Habitation module. Although I first touted an Aluminium/Lithium or composite structure for the Trans-Hab, I concede that an inflatable Kevlar module would certainly be superior, mass-wise. Line it with lots of polyethylene - good enough for nuclear subs - and then radiation be damned!! I still think a minimum crew of 3 or 4 would be more suitable for an actual landing mission and 2x crew for a Demos/Phobos survey. However, it seems that for the Descent and Ascent vehicles and Earth re-entry, the size of the Dragon for a crew of 2,3 or 4 is quite adequate for these tasks. So let's not worry about their size for most tasks from now on, I say.

Devil being in the details: Hypergolics for the final, propulsive descent after aero-heatshield and parachute? I'd like folk's thoughts on that: because the Descent vehicle would be in space for quite awhile and Hypergolics have proven long-term storage abilities. Of course, the Dragon-based Ascent vehicle's propulsion should be LOX/CH4. I've always thought that Martian ISRU is the 'magic bullet' that will make this darn thing work: not to mention for fueling the Pressurized Rover. And a derivative of the Trans-Hab inflatable for the surface living quarters -- inflate with pure O2 at 5 psi for a long term stay? Or carry some nitrogen all the way to Mars and do a 5psi, 60% nitrogen, 40% O2 combination?

And finally -- just harking back to a 2x man mission for a moment: what are people's thoughts about doing a short-stay 14-to-20 day 'sprint' for the initial 'test' mission? Enough of a big workload for a mere 2 Astronauts to accomplish? Apollo 11 stayed on the Moon for 21 hours compared to Apollo 17's 75 hour stay. And 15,16 & 17's lunar Rovers made the longer stay very much worth it.

I know it would be partly a symbolic mission compared to a full, 18 month stay. But a mass of scientific data would still be collected and a daring, complex mission architecture would be demonstrated at a risk/duration perceived to be, if not actually much less than an 18-month stay.

'Baby steps' to be followed by larger crews with longer stays later? And even if each launch window to Mars needed 5 or 6 Falcon Heavy launchers to get each mission underway, this would still be much cheaper than a 6x Ares V 'Battlestar Galactica' 6x person Mars mission.

Yes, I feel Dr Zubrin is essentially on the right path. Though if he is graciously open to (sensible) suggestions, I wonder if some of us can help him 'tweak' this thing into existence. I'd love virtually more than anything else the chance to see this mission happen at a pragmatic, non-lunatic price tag in 10-to-12 years that can be paid for with a careful alliance of Private Space Investors, Entrepreneurs, Altruists and maybe a dash of dear old NASA money as well.

"The future doesn't belong to the faint-hearted; it belongs to the brave."  Ronald Reagan.

Guys; we need some of that! :)
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Michael Bloxham on 05/16/2011 09:54 am
Interesting plan, albeit pretty limited capability-wise.

IMO adding a few more Falcon launches to add further redundancy/capability (for example by pre-positioning assets in Mars orbit and on the surface) or the addition of a high-energy upper stage to the Falcon Heavy to increase its trans-Mars throw mass will probably be necessary to make the plan "fly" politically (reducing risk), or if you want more than just a flags/footprints mission with two astronauts and a Dragon on Mars.

You could also send two of these minimalistic missions together - side-by-side.

If precision-landed, this could allow for a full crew of four on the surface per mission, and also provide dual-redundancy (two of everything in case one fails).

If the Dragon descent capsule is replace by a more conventional dedicated Mars lander capable of delivering a small mobile habitat (perhaps in the same manner as MSL), then precision landing is not needed - and a great deal more exploration and science can be achieved.

Over at MarsDrive, we spent a few years exploring just such a concept. See http://forum.nasaspaceflight.com/index.php?topic=17360.msg676398#msg676398 and http://forum.nasaspaceflight.com/index.php?topic=17360.msg685877#msg685877 and http://groups.yahoo.com/group/marsdrivemission/attachments/folder/0/list

The 53-tonne to LEO capability of the Falcon Heavy didn't exist then, so we went with an arbitrary 60-tonne launcher. So if you shrink everything down just a bit, you could probably squeeze this architecture onto 6 launches of the Falcon Heavy.

- Mike

Edit: Of course, this is just a concept. Critical discussion is welcome - but is probably best directed to its dedicated thread - so as to not derail this one.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Michael Bloxham on 05/16/2011 11:45 am
2. EDL
Using just its aeroshield for deceleration, the Dragon would have a terminal velocity of around 340 m/s on Mars at low altitude (air density 16 gm/m3). So we could either give it a rocket delta-V capability of 600 m/s (a 20% mass hit assuming storable or RP/O2 propulsion, Isp~330 s) to land all propulsive, or we could use a drogue to slow it down (a 20 m diameter chute would slow it to ~70 m/s) and then employ a much smaller rocket delta-V for landing.

Robert

Hi Robert. Good to see you on the forums!

I have a question and a suggestion.

While I am sure that using a Dragon capsule as a Mars lander is possible, I wonder whether the development expenditure required - for the mechanical aids such a feat would require (retro-propulsive stage, aerodynamic decelerators, etc.) and re-engineering and qualification effort - would better be spent on the development of a more logical evolution of heritage Viking/MER/MSL EDL technologies to achieve the same performance?

I imagine it would not be too difficult to scale up MSL-derived EDL tech to the point where its useable surface payload capacity is much better than that of a modified Dragon spacecraft such as the type that you propose?

Such a purpose-built Mars lander might also serve the future needs of an initial Mars base much better and more cheaply than Dragon.

- Mike
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Ralph Buttigieg on 05/16/2011 01:28 pm


I think the private exploration element needs more discussion. What would the cost of a Amundsen/Scott type of exploration program to Mars. Is our technology baseline high enough to make the risk comparable to those Antarctic missions from the last century? Are there similar explorers today to risk life and fortune to expand the human frontier. NASA will likely require another 40 years to get to Mars with their collective risk aversion (Congressional and media oversight, changing priorities, changing presidents...). This could change if China challenges us and we choose to respond, but based on our current funding and support culture at NASA, it is difficult to see a human mission before the 2030's at best.
The only way for us to get to Mars in my lifetime is for a President to commit to it, and be willing to spend about 10 times the real mission cost, or private exploration. Would Paul Allen or someone be willing to spend $500 million to sponsor a mission? Branson has his money tied up in Virgin Space, or he would be a logical rich guy willing to risk his life guy. Could it be done for less than a billion? I see a lot of engineering math, but less financial math, and the more difficult to quantify math about personal risk. I know Musk wants to do this, but can he afford this without some big third party funding?
How little could a private mission be done with? Keep in mind, once an initial private mission is completed, more missions will follow and risks once defined empirically, can be better understood by politicians and our larger society.
[/quote]

Dave, the only serious project for an actual beyond low Earth orbit human mission today is from the private sector. Space Adventures moonshot. They already have one person signed up and hope for the second soon.

But lets look at polar exploration. Explorers like Amundsen would borrow money and pay off their debts by giving lectures, writing books etc.  If fact Amundsen had to go to the South Pole because he was beaten to the North by Peary and Amundsen had to pay off his creditors. In todays world we would act things like TV rights, internet subscriptions etc.

I would think the cash flow from the first Mars expedition would be substantial.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: majormajor42 on 05/16/2011 02:21 pm
"Zubrin's" Falcon Heavy Mars Mission  ???

Musk risks his personal fortune and millions of NASA/taxpayer $$$
We triumphantly land on Mars.
Zubrin: "You're welcome"

In comparison to the 11.1 Billion we wasted on Constellation or the 10 billion more we waste on the Senate Launch System, we are getting new capability and it is an acceptable risk.  Even if Musk was 10 years late it would still be better than the poppycock we are getting from NASA and congress.

VR
TPIS
RE327

my point is what is Zubrin adding to the FH Mars concept that wasn't already discussed in other threads or (more than likely) Musk and team have already run some numbers on and might be perusing.

The title of this thread should be "Zubrin endorses Musk/SpaceX Falcon Heavy Mars Mission/Ambitions"

In the end, to steal a line from Social Network, if Zubrin built a Mars rocket, he would have built a Mars rocket.



btw, I bought A Case for Mars hardcover way back when.  Great ideas. Read First Landing, very inspirational.  And had a ball reading Holy Land too.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: MikeAtkinson on 05/16/2011 03:37 pm

2. EDL
Using just its aeroshield for deceleration, the Dragon would have a terminal velocity of around 340 m/s on Mars at low altitude (air density 16 gm/m3). So we could either give it a rocket delta-V capability of 600 m/s (a 20% mass hit assuming storable or RP/O2 propulsion, Isp~330 s) to land all propulsive, or we could use a drogue to slow it down (a 20 m diameter chute would slow it to ~70 m/s) and then employ a much smaller rocket delta-V for landing.

Robert

My understanding of Mars EDL is limited, but from what I've read Dragon would not reach terminal velocity before hitting the ground. It would seem to require 500-1000 m/s of rocket delta-V.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: mrmandias on 05/16/2011 09:07 pm
my point is what is Zubrin adding to the FH Mars concept that wasn't already discussed in other threads or (more than likely) Musk and team have already run some numbers on and might be perusing.


Zubrin/Mars Society and "Musk and team" aren't as unrelated entities as you might think.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Robotbeat on 05/16/2011 10:09 pm

2. EDL
Using just its aeroshield for deceleration, the Dragon would have a terminal velocity of around 340 m/s on Mars at low altitude (air density 16 gm/m3). So we could either give it a rocket delta-V capability of 600 m/s (a 20% mass hit assuming storable or RP/O2 propulsion, Isp~330 s) to land all propulsive, or we could use a drogue to slow it down (a 20 m diameter chute would slow it to ~70 m/s) and then employ a much smaller rocket delta-V for landing.

Robert

My understanding of Mars EDL is limited, but from what I've read Dragon would not reach terminal velocity before hitting the ground. It would seem to require 500-1000 m/s of rocket delta-V.
Has anyone ever actually simulated that? (I actually probably could, but it'd take a lot of time...) I've just heard speculation to that effect.

Also, EDL performance depend pretty strongly on where you plan on landing. Try to land on Mount Olympus (~21km above "sea level", standard topographic datum), and you may well just be adding another crater. But landing at Hellas Basin (7km below "sea level" and with almost twice the air pressure as "sea level" on Mars) is may be quite a different story.

Also, it depends strongly on the incoming velocity and how much lift can be produced. And ~500m/s isn't necessarily out of the question for Dragon.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: sanman on 05/16/2011 11:55 pm
I'd like to ask Dr Zubrin why such a Mars mission would need to be done in such a minimalist fashion at such an absolutely shoestring cost? Isn't there such a thing as going too cheap?

Given the momentous importance of a manned Mars mission, why wouldn't it be worth it to spend a few more billion$ to increase the safety margins, the redundancies, and to improve the knowledge returned from the mission?

Or, alternatively, if the F9H business model is sustainable, why not let it succeed and evolve into even better cost/lb to allow even more mission for the buck? What timeclock are we racing against, that a mission has to be done within this decade? How about 2025?

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: QuantumG on 05/17/2011 12:05 am
What timeclock are we racing against, that a mission has to be done within this decade? How about 2025?

The existential question being asked every year...
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Jim on 05/17/2011 12:58 am
my point is what is Zubrin adding to the FH Mars concept that wasn't already discussed in other threads or (more than likely) Musk and team have already run some numbers on and might be perusing.


Zubrin/Mars Society and "Musk and team" aren't as unrelated entities as you might think.

Huh?  Yes they are
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: sanman on 05/17/2011 02:09 am
The existential question being asked every year...

Well, why can't Musk send Man back to the Moon first, during this decade? Then we can do Mars the next decade.

The Moon is a lot closer, and can be a nice dry run for all the man-rated life-support stuff. Do a bunch of manned missions there first, during this decade. Improve the return vehicles, improve the spacesuits, improve the nuclear reactors, improve the solar arrays, improve the dune buggies, improve the portable gardens, make the lavatory systems more reliable, etc.

If F9H is as cheap as Musk says it's going to be, then going back to the Moon first won't really sap away funds from a Mars mission. If anything, it would revitalize the public interest and enthusiasm so that more funding would be unleashed for the Mars mission.

Musk has moved pretty rapidly to F9H, and if he moves at a similar pace towards a F-XX/superheavy, then what better use for such a rocket than Mars?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: QuantumG on 05/17/2011 02:21 am
Well, why can't Musk send Man back to the Moon first, during this decade? Then we can do Mars the next decade.

Musk has no intention of sending people to Mars or the Moon.. and he won't until someone who wants to pay for it says they do.  I really wish people would listen to what Elon says rather than what they want him to say. 

Quote
If F9H is as cheap as Musk says it's going to be, then going back to the Moon first won't really sap away funds from a Mars mission. If anything, it would revitalize the public interest and enthusiasm so that more funding would be unleashed for the Mars mission.

It's Falcon Heavy now, they dropped the 9.. I'll tolerate it from Zubrin but not you :)   If you want to go to the Moon, convince someone to pay for a Moon mission.  If that's NASA they'll want to do it with their own rockets because it supports what they care about.  If you want to do it privately, go raise the money.  You can't pin all your hopes and dreams to Elon Musk.. the guy has already done miracles  (as has Mr Bigelow), it's time for someone else to step up.

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Sen on 05/17/2011 03:17 am
I'd like to ask Dr Zubrin why such a Mars mission would need to be done in such a minimalist fashion at such an absolutely shoestring cost? Isn't there such a thing as going too cheap?

Given the momentous importance of a manned Mars mission, why wouldn't it be worth it to spend a few more billion$ to increase the safety margins, the redundancies, and to improve the knowledge returned from the mission?

Or, alternatively, if the F9H business model is sustainable, why not let it succeed and evolve into even better cost/lb to allow even more mission for the buck? What timeclock are we racing against, that a mission has to be done within this decade? How about 2025?



It needs to be as bare bones as possible IF the goal is to take said plan not to the government, but insted the private sector/patrons for funding. That can then snowball with sponsors, etc to evolve the program into something thats more then a one off event. Something REALLY bare bones, less then a billion like this plan (that assumes dev work by spacex and others as a part of the program.) Id rather start farther up the food chain with a larger mission, but getting a 20 billion dollar pledge is harder then getting a one billion dollar one.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: DaveH62 on 05/17/2011 03:18 am
Well, why can't Musk send Man back to the Moon first, during this decade? Then we can do Mars the next decade.

Musk has no intention of sending people to Mars or the Moon.. and he won't until someone who wants to pay for it says they do.  I really wish people would listen to what Elon says rather than what they want him to say. 

Quote
If F9H is as cheap as Musk says it's going to be, then going back to the Moon first won't really sap away funds from a Mars mission. If anything, it would revitalize the public interest and enthusiasm so that more funding would be unleashed for the Mars mission.

It's Falcon Heavy now, they dropped the 9.. I'll tolerate it from Zubrin but not you :)   If you want to go to the Moon, convince someone to pay for a Moon mission.  If that's NASA they'll want to do it with their own rockets because it supports what they care about.  If you want to do it privately, go raise the money.  You can't pin all your hopes and dreams to Elon Musk.. the guy has already done miracles  (as has Mr Bigelow), it's time for someone else to step up.



So to run with the slightly (way) off topic trip to the moon first and who's to pay. Could a James Cameron type of person fund or lead a moon mission and pay for it as an HBO series? If he can make 2 billion on Avatar, could he recoup $250 million for a moon mission? Could a single Falcon Heavy deliver a full exploration payload. A Dragon capsule, a small Bigelow habitation container, a vehicle and a satellite with a 3d camera and maybe some small video probes to drop in interesting craters or lava tubes. To do a proper video shoot, I would guess you would need at least 5 people. To capture enough video to create an HBO series, the team would need to stay at least 6 weeks. With naming rights and other marketing options, you should be able to raise at least $100 million prelaunch, another $100 million from HBO or another network/cable sponsor and then your iMax and other add-ons should get at least a break even commercial opportunity.
This might detract from some cool mythological naming options, to the Lunar Dew, the Oreo lander, or the Bigelow Mac, but it could provide a sustainable private path to exploration while longer term mining and science issues get worked out.
Apologies if I've jumped from propeller head to tin foil hat, but I think the only near term way to speed things up is for non government operations. Grid lock seems too great to compromise even with some of the great options we have right now.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: go4mars on 05/17/2011 03:23 am
Robert,
You turned me into a space nerd.  Thankyou!  I was on a road trip from Calgary, and found myself in the KSC gift-shop book section, wondering when and how NASA was going to Mars.  I found "The Case for Mars", and hundreds of other space books and articles since.  This might not be the right place, but I have 2 questions:   Where did the Mars Society forum go?  There was tons of great stuff in there, but the link seems to have disappeared when the website went from black to white.  Also, what happened with Tom Hill's tether demonstrator TEMPO-3?  I couldn't find anything on the new website related to that either. 

Cheers.  MARS OR BUST!   ON TO MARS!!    ET CETERA!!!

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: go4mars on 05/17/2011 03:30 am
...if you want more than just a flags/footprints mission with two astronauts and a Dragon on Mars.

There is no such thing as just a flags/footprints mission to Mars assuming geologists are wandering around for 2 years.  They can't help but learn a lot about Mars and hardware ideas for making things work a bit better for the next crew who arrives there.   Even if a global sandstorm crops up again for the entire duration, they would still learn a lot.  Remember, a human mission is also a sample return mission. 
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: QuantumG on 05/17/2011 03:37 am
Could a James Cameron type of person fund or lead a moon mission and pay for it as an HBO series?

What ask me?  Go ask them.  :)
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: JNobles on 05/17/2011 03:42 am
Quote
Could a James Cameron type of person fund or lead a moon mission and pay for it as an HBO series?

If they filmed it as a reality series like Survivor and voted people off.




(sorry)


Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: M_Puckett on 05/17/2011 03:58 am
Robert,
You turned me into a space nerd.  Thankyou!  I was on a road trip from Calgary, and found myself in the KSC gift-shop book section, wondering when and how NASA was going to Mars.  I found "The Case for Mars", and hundreds of other space books and articles since.  This might not be the right place, but I have 2 questions:   Where did the Mars Society forum go?  There was tons of great stuff in there, but the link seems to have disappeared when the website went from black to white.  Also, what happened with Tom Hill's tether demonstrator TEMPO-3?  I couldn't find anything on the new website related to that either. 

Cheers.  MARS OR BUST!   ON TO MARS!!    ET CETERA!!!



Ronnie Cox did both!  Start the reactor Quade!
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: sanman on 05/17/2011 04:01 am
Haha, well maybe you've got an idea there - Reality TV. Instead of Sci-Fi, you have Sci-Real.

For Series One, first send Cameron to space.
For Series Two, send him to the Moon.
For Series Three, send him to Mars.

Personally, I think that robot sports on the Moon or even Mars could become a big spectator sport. Use robots rather than real athletes, since robots are cheaper and easier to send and look after out there. Develop a 2-legged version of Robonaut, and send 12 of them there for 6-on-6 lunar games of various types.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Dave G on 05/17/2011 04:01 am
A manned Mars mission will last about 2.5 years:
- 6 months to travel to Mars
- 18 months on Mars surface (waiting for the planets to re-align)
- 6 months to travel back to Earth

That's a long time.  In order to do that, we'll need:
1) New life support systems that recycle most consumables (air, water, food).
2) New ways to deal with low gravity and zero gravity for years at a time.
3) New space suits that allow full range motion and last for years.
4) More general experience with missions that last years instead of months.
5) A practical way to deal with harmful radiation that would normally be shielded by Earth's magnetic field.

Here's an analogy: Everyone talks about Apollo, but it was really Gemini that paved the way to the moon.  Gemini gave us experience with rendezvous, longer duration flight, and EVA - all essential for getting to the moon.

Before we go to Mars, we’ll need the equivalent of what Gemini did for Apollo.  Something that gives us the experience to perfect the systems necessary for a manned Mars mission.  Experience with low gravity, very long duration missions, and other technologies that will allow humans to survive away from Earth for years.

I believe the best way to do this is with a permanent moon base.  We should have a permanent human presence on the Moon.  This will give us the experience we need to go to Mars, like Gemini did for Apollo.

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Michael Bloxham on 05/17/2011 04:25 am
Before we go to Mars, we’ll need the equivalent of what Gemini did for Apollo.  Something that gives us the experience to perfect the systems necessary for a manned Mars mission.  Experience with low gravity, very long duration missions, and other technologies that will allow humans to survive away from Earth for years.

ISS?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: go4mars on 05/17/2011 04:35 am
A manned Mars mission will last about 2.5 years:
we'll need:
1) New life support systems that recycle most consumables (air, water, food).
2) New ways to deal with low gravity and zero gravity for years at a time.
3) New space suits that allow full range motion and last for years.
4) More general experience with missions that last years instead of months.
5) A practical way to deal with harmful radiation that would normally be shielded by Earth's magnetic field.

1)  Pretty much have that commercially available already as I understand it.
2)  Gemini already played around with tether demonstrators.  Another couldn't hurt, but it might as well be tested out en route to Mars.  If it works, great, if not, the next crew will hopefully get it figured out.  It is not mission critical.  The best way to collect this data and test methods is by doing them in a real mission.
3)  Yep.  Some X prizes would be useful.  A pressure-suit with a be-pocketed wool/polarbear fur overcoat and boot heaters should do the trick.  Exposed fingertips might need a tight bit of duct tape in the mornings.  And some warm mittens for when not using fingertips.  A few lightweight suits could be sent along to test out pros and cons of various ideas. 
4)  Best way to get that experience is to do the mission imo.
5)  That problem does not appear to be going away.  I don't think we need to wait for a breakthrough in materials sciences on that one or we'll never get there. 
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: go4mars on 05/17/2011 04:40 am
Here's an analogy: Everyone talks about Apollo, but it was really Gemini that paved the way to the moon.  Gemini gave us experience with rendezvous, longer duration flight, and EVA - all essential for getting to the moon.

Before we go to Mars, we’ll need the equivalent of what Gemini did for Apollo.  Something that gives us the experience to perfect the systems necessary for a manned Mars mission.

Apollo, Gemini, ISS, etc. have taken care of a lot of that already.  If anything, the first mission to Mars will be an even better "Gemini equivalent" for the second mission to Mars. 
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: QuantumG on 05/17/2011 04:49 am
we'll need:
1) New life support systems that recycle most consumables (air, water, food).
2) New ways to deal with low gravity and zero gravity for years at a time.
3) New space suits that allow full range motion and last for years.
4) More general experience with missions that last years instead of months.
5) A practical way to deal with harmful radiation that would normally be shielded by Earth's magnetic field.

Lists like this are helpful but here's another list for you:

1) Recognition of what we already know (for example, radiation protection on Earth is primarily a function of the atmosphere not the magnetic field)
2) Plans for how to learn all the things we know we don't know.. like how the human body reacts to partial gravity.
3) A willingness to accept that there are still plenty of things we don't even know that we don't know.

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Steven Pietrobon on 05/17/2011 07:24 am
3. The preferred method of Mars capture is aerocapture, rather than direct entry. This means that the Dragon aeroshield, which has some lifting capability, may well be adequate. To see this with a back of the envelope calculation, consider a loaded Dragon system with an entry mass of 17000 kg, an effective shield diameter of 4 meters, a drag coeffecient of 1, coming in with an entry velocity of 6 km/s at an altitude of 33 km, where the Mars atmospheric density is 0.8 gm/m3. Setting drag equal to mass times deceleration, you can see that the system would decelerate at a speed of 42 m/s2, or a little over 4 gs. It could thus perform a 1 km/s deceleration in about 25 seconds, during which time it would travel about 140 km. This deceleration is sufficient to capture the spacecraft from an interplanetary trajectory into a loosely bound highly elliptical orbit around Mars.

Deceleration for a circular body in air is [1]

a_d = C_d*pi*(D*v)^2*rho/(8*m)

where

C_d = coefficient of drag = 1
pi = 3.14159
D = diameter = 4 m
v = speed = 6000 m/s
rho = air density = 0.0008 kg/m^3
m = mass = 17,000 kg

Using these numbers, I get a_d = 10.64 m/s^2. Looks like you forgot to divide by four in calculating the area using the diameter. The time taken to decelerate from v_i = 6000 m/s to v = 5000 m/s is given by the formula [2]

t_d = (1/v - 1/v_i)/c_t = 112.7 s

where

c_t = C_d*pi*D^2*rho/(8*m) = 2.957e-7 m^{-1}.

This compares with the approximate time of (v_i-v)/a_d = 93.9 s assuming a constant deceleration (which is not the case). The total distance travelled is (obtained by integrating v = 1/(t*c_t+1/v_i))

s_d = ln(v_i/v)/c_t = 616,619 m

compared to the (incorrect) constant deceleration distance of (v_i^2-v^2)/(2*a_d) = 516,701 m, which is 16% less. In summary
                              RZ   SSP
Initial Deceleration (m/s^2)  42   10.64
Time (s)                      25  112.7
distance (km)                140  616.6

Of course, the Mars atmosphere is not a step wise function. The actual required entry height will need to be determined in an iterative process using numerical integration of the trajectory, based on current data of the atmospheric density profile.

2. EDL
Using just its aeroshield for deceleration, the Dragon would have a terminal velocity of around 340 m/s on Mars at low altitude (air density 16 gm/m3). So we could either give it a rocket delta-V capability of 600 m/s (a 20% mass hit assuming storable or RP/O2 propulsion, Isp~330 s) to land all propulsive, or we could use a drogue to slow it down (a 20 m diameter chute would slow it to ~70 m/s) and then employ a much smaller rocket delta-V for landing.

The terminal velocity equation is

v_t = sqrt(2*m*g_m/(rho*A*C_d))

where

m = mass = 11,000 kg (value obtained from article)
g_m = surface gravity = 3.711 m/s^2
rho = surface air density = 0.016 kg/m^3
D = diameter = 4 m
A = area = pi*D^2/4 = 12.57 m^2
C_d = coefficient of drag = 1

This gives v_t = 637.2 m/s, nearly double your value of 340 m/s. Again, it looks like you forgot to divide the area by four when calculating the area from the diameter. For a 20 m diameter chute the terminal velocity is 127.4 m/s, 82% greater than your calcuation of 70 m/s.

[1] W. von Braun, "The Mars Project," The University of Illinois Press, 1953.

[2] dv/dt = -c_t*v^2
-v^{-2} dv = c_t dt
1/v = c_t*t + c
For v = v_i and t = 0 implies c = 1/v_i. Thus for t = t_d
1/v = c_t*t_d + 1/v_i
t_d = (1/v-1/v_i)/c_t
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: majormajor42 on 05/17/2011 11:19 am
Well, why can't Musk send Man back to the Moon first, during this decade? Then we can do Mars the next decade.
Musk has no intention of sending people to Mars or the Moon.. and he won't until someone who wants to pay for it says they do.  I really wish people would listen to what Elon says rather than what they want him to say. 
Quote
If F9H is as cheap as Musk says it's going to be, then going back to the Moon first won't really sap away funds from a Mars mission. If anything, it would revitalize the public interest and enthusiasm so that more funding would be unleashed for the Mars mission.
It's Falcon Heavy now, they dropped the 9.. I'll tolerate it from Zubrin but not you :)   If you want to go to the Moon, convince someone to pay for a Moon mission.  If that's NASA they'll want to do it with their own rockets because it supports what they care about.  If you want to do it privately, go raise the money.  You can't pin all your hopes and dreams to Elon Musk.. the guy has already done miracles  (as has Mr Bigelow), it's time for someone else to step up.

I think Musk has every intention of going to Mars. According to his words it is the whole point of all this. He (spacex) even had that video with clips of a Dragon capsule landing on Mars with habitat and ascent module in the background. How is advertising this Mars capability not some form of intent? I'll agree that he might not, at this point, intend on funding the whole thing himself and hopes to get as much NASA/gov't support (money/launch facilities...) as possible. But he does intend on sending people to Mars.

I do admit I pin a lot of hope and dreams on Elon's intent to go to Mars.  However, I am not asking/hoping that it is done this decade at all. The guy has done some great things and now is the time to focus on the logical next steps, the ones that have been scheduled, such as ramping up Falcon production, fulfilling COTS/CRS, launching FH, and closing the gap with CCDev.  Those will all be great things and will be very satisfying.  Throw in Bigelow and millionaire-next-door sub-orbital flights and this decade is looking very promising.  That's why I believe in the mantra that before this decade is out, there will be a boom in human spaceflight. Specifically, that we will have 500 humans additional humans in space before 2020, roughly double the number up to 2010.

Now, a question for everyone, getting back to Elon's Mars intentions, how do those pictures (which are worth a thousand words) of Dragon landing on Mars, with the additional hardware in the background, differ from Zubrin's thousand word essay (and comments here).

http://www.spacex.com/multimedia/videos.php?id=58&cat=recent (http://www.spacex.com/multimedia/videos.php?id=58&cat=recent)

Musk has said that best case (fully funded support I guess), he could get to Mars in 10 years, and worst case (his intent to self fund) 15-20 years.  So a difference is that Zubrin is saying that we, or better yet he (Musk/SpaceX) could deliver this mission in 5 years if NASA/gov't/somebody paid for it. But talk of timelines is fluff anyway, except when it comes to budgets. So unless Zubrin thinks he can open the door to funding this mission, timelines are just numbers. But what are the technical differences of Zubrin's outline that could shave 5 years off the forecast?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: QuantumG on 05/17/2011 12:10 pm
SpaceX is aiming to be the transportation system to Mars.. they've never said they're planning a Mars mission themselves.  Elon has tried to make this clear in every interview but people hear what they want to hear.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: ChefPat on 05/17/2011 12:20 pm
SpaceX is aiming to be the transportation system to Mars.. they've never said they're planning a Mars mission themselves.  Elon has tried to make this clear in every interview but people hear what they want to hear.

Elon Musk has also said he wants to retire on Mars.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Jim on 05/17/2011 12:53 pm

1)  Pretty much have that commercially available already as I understand it.
2)  Gemini already played around with tether demonstrators.  Another couldn't hurt, but it might as well be tested out en route to Mars.  If it works, great, if not, the next crew will hopefully get it figured out.  It is not mission critical.  The best way to collect this data and test methods is by doing them in a real mission.
3)  Yep.  Some X prizes would be useful.  A pressure-suit with a be-pocketed wool/polarbear fur overcoat and boot heaters should do the trick.  Exposed fingertips might need a tight bit of duct tape in the mornings.  And some warm mittens for when not using fingertips.  A few lightweight suits could be sent along to test out pros and cons of various ideas. 
4)  Best way to get that experience is to do the mission imo.
5)  That problem does not appear to be going away.  I don't think we need to wait for a breakthrough in materials sciences on that one or we'll never get there. 


1.  no, it is not
2.  Played is the right term.  there are still many issues to work out.  No, a mission is not the right place to work it out. 
4.You have demonstrated why you are not in charge.  You will kill people
5. guess what, you are not getting there unless this is fix
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: sanman on 05/17/2011 05:24 pm
The basis for Dr Zubrin's proposal seems to be the arrival of the Falcon Heavy with its new low in cost/lb, as a game-changer.

But who's to say there aren't even more game-changers around the corner?

I'd like to ask - what other critical breakthroughs would be useful as game-changers, to make a manned mission to Mars much more feasible than before?

Who are the likely sources of such breakthroughs?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: baldusi on 05/17/2011 06:49 pm
A SEP upper stage. A Rad Hardened solar panel (to use the SEP to cross the Van Allen belt). A depot architecture. A fully developed suitport. There are lots and lots of thing before shiny big rockets. But I like to draw a parallel with the panda. The Panda is a bear with an incredibly bad fitness for a changing environment, that accomplish basically no ecological work, protecting just a few surviving individuals needs horrendous amounts of resources and don't even likes to have sex. But it's oh so cute and lots and lots of money are put into taking care of it. There are literally thousands of other species that are way more important to take care of, and that would need only a fraction of the money and effort put into the panda, but since they are not cute, they get no money nor press. HLV is the panda, the rest of the colonization technologies are the rest.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Karloss12 on 05/17/2011 07:03 pm
A manned Mars mission will last about 2.5 years:
- 6 months to travel to Mars
- 18 months on Mars surface (waiting for the planets to re-align)
- 6 months to travel back to Earth

That's a long time.  In order to do that, we'll need:
1) New life support systems that recycle most consumables (air, water, food).
2) New ways to deal with low gravity and zero gravity for years at a time.
3) New space suits that allow full range motion and last for years.
4) More general experience with missions that last years instead of months.
5) A practical way to deal with harmful radiation that would normally be shielded by Earth's magnetic field.

Here's an analogy: Everyone talks about Apollo, but it was really Gemini that paved the way to the moon.  Gemini gave us experience with rendezvous, longer duration flight, and EVA - all essential for getting to the moon.

Before we go to Mars, we’ll need the equivalent of what Gemini did for Apollo.  Something that gives us the experience to perfect the systems necessary for a manned Mars mission.  Experience with low gravity, very long duration missions, and other technologies that will allow humans to survive away from Earth for years.

I believe the best way to do this is with a permanent moon base.  We should have a permanent human presence on the Moon.  This will give us the experience we need to go to Mars, like Gemini did for Apollo.



5)  The super powerfull cryomagnet that was finished and replaced by a weak permanent magnet on Alpha Magnetic Spectrometer that was launched yesturday is the best effort so far.

The following article talks all about its capabilities.

http://www.bbc.co.uk/news/science-environment-13411163
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: usarian on 05/17/2011 07:28 pm
This idea is exciting!

You all are debating things way outside of my area of expertise, but if it's not an imposition, I'd like to ask all your opinions about adding a VASIMR VF-200 tug into the mix.. what would be the cost/benefit of having a vehicle capable of spinning up other vehicles and releasing them in trajectory, then spinning itself back down to be used again.

What I wonder is if it could cut the amount of chemical fuel that would need to be launched and then carried as it's burned on the way to Mars (or anywhere).

Do you think the cost of developing and launching such a vehicle would be offset by cost savings for interplanetary missions?

Appreciate your patience
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Cog_in_the_machine on 05/17/2011 08:04 pm
This idea is exciting!

You all are debating things way outside of my area of expertise, but if it's not an imposition, I'd like to ask all your opinions about adding a VASIMR VF-200 tug into the mix.. what would be the cost/benefit of having a vehicle capable of spinning up other vehicles and releasing them in trajectory, then spinning itself back down to be used again.

Welcome to the forum. I take it you're not familiar with Zubrin's philosophy? To put it in his words:

"In principle, it can take any amount of rope to connect two posts separated by 10 metres. The issue is whether you want to connect the posts or sell rope."

Translation - advanced propulsion is pork and is to be avoided. Same goes for the things mentioned in this picture (http://titlesequences.com/mac/images/downloads_cowards/5_info_pane_for_T-Shirt_backs_web.png).
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: baldusi on 05/17/2011 08:30 pm
Translation - advanced propulsion is pork and is to be avoided.

Well, VASIMR is a 45M project. It won't break the bank and it's very interesting. The 39 days to Mars with a 2000W/kg imaginary source, that's crazy. Many technologies are really worth investing on. In small amounts, and as fully commercial if possible. It's the multi billion monstrosities the problem. And the throw everything because in a decade we'll have something from the next 50 years.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Downix on 05/17/2011 08:36 pm
This idea is exciting!

You all are debating things way outside of my area of expertise, but if it's not an imposition, I'd like to ask all your opinions about adding a VASIMR VF-200 tug into the mix.. what would be the cost/benefit of having a vehicle capable of spinning up other vehicles and releasing them in trajectory, then spinning itself back down to be used again.

Welcome to the forum. I take it you're not familiar with Zubrin's philosophy? To put it in his words:

"In principle, it can take any amount of rope to connect two posts separated by 10 metres. The issue is whether you want to connect the posts or sell rope."

Translation - advanced propulsion is pork and is to be avoided. Same goes for the things mentioned in this picture (http://titlesequences.com/mac/images/downloads_cowards/5_info_pane_for_T-Shirt_backs_web.png).
By that claim, we've never constructed anything in LEO.  I have a $100 billion investment which tells me that claim is bogus.

LEO construction is not pork, nor a long pole.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Cog_in_the_machine on 05/17/2011 08:45 pm
LEO construction is not pork, nor a long pole.

For the record, you don't need to convince me of that. I posted that because it's a compact way of explaining the gist of Mars Direct.

Baldusi, I'm an R&D proponent. I'm already of the opinion that advanced technologies should be pursued more than NASA does currently, no need to point it out to me.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Downix on 05/17/2011 08:48 pm
LEO construction is not pork, nor a long pole.

For the record, you don't need to convince me of that. I posted that because it's a compact way of explaining the gist of Mars Direct.
It is, and it also shows how the Mars Direct concept has been eclipsed by new capability.  When originally proposed, Mars Direct was the cats meow.  Now, we can do so much more, for less, thanks to our new capability.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Cog_in_the_machine on 05/17/2011 08:58 pm
It is, and it also shows how the Mars Direct concept has been eclipsed by new capability.

Falcon and Dragon?

Quote
When originally proposed, Mars Direct was the cats meow.  Now, we can do so much more, for less, thanks to our new capability.

Last I checked, the only space related thing I own is an account on this forum. Perhaps you have more, but anyway if the new capability you're referring to is SpaceX's launcher, I don't see how that makes that description of the central idea behind Mars Direct less applicable. Unless Zubrin has all of a sudden changed his architecture to involve  either on orbit assembly, lunar propellant or some form of advanced propulsion. If so, that would be news to me.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Joris on 05/17/2011 09:39 pm
It is, and it also shows how the Mars Direct concept has been eclipsed by new capability.

Falcon and Dragon?

Quote
When originally proposed, Mars Direct was the cats meow.  Now, we can do so much more, for less, thanks to our new capability.

Last I checked, the only space related thing I own is an account on this forum. Perhaps you have more, but anyway if the new capability you're referring to is SpaceX's launcher, I don't see how that makes that description of the central idea behind Mars Direct less applicable. Unless Zubrin has all of a sudden changed his architecture to involve  either on orbit assembly, lunar propellant or some form of advanced propulsion. If so, that would be news to me.

I think he is referring to the experience we gained since the beginning of the DRM's and Mars Direct, in orbital rendezvous and LEO-construction.

It used to be discarded simply because it was too difficult or dangerous, which is no longer the case nowadays.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Downix on 05/17/2011 10:45 pm
It is, and it also shows how the Mars Direct concept has been eclipsed by new capability.

Falcon and Dragon?

Quote
When originally proposed, Mars Direct was the cats meow.  Now, we can do so much more, for less, thanks to our new capability.

Last I checked, the only space related thing I own is an account on this forum. Perhaps you have more, but anyway if the new capability you're referring to is SpaceX's launcher, I don't see how that makes that description of the central idea behind Mars Direct less applicable. Unless Zubrin has all of a sudden changed his architecture to involve  either on orbit assembly, lunar propellant or some form of advanced propulsion. If so, that would be news to me.

I think he is referring to the experience we gained since the beginning of the DRM's and Mars Direct, in orbital rendezvous and LEO-construction.

It used to be discarded simply because it was too difficult or dangerous, which is no longer the case nowadays.
Right.  Add in re-use.  We have already demonstrated that we can build and operate structures in space for long periods. Adapting that to exploration, now you can get somewhere.

And Falcon Heavy can fully be part of this.  In fact, the lifting capacity of the Falcon Heavy makes it, if the SLS should not be available, uniquely ideal for such a mission. 

I know why Dr Zubrin would prefer the direct launch approach, it's simpler.  At the same time, there is no compelling argument against having a more capable mission with the addition of another launch or two.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Michael Bloxham on 05/18/2011 03:38 am
SpaceX is aiming to be the transportation system to Mars..

The basis for Dr Zubrin's proposal seems to be the arrival of the Falcon Heavy with its new low in cost/lb, as a game-changer.

But who's to say there aren't even more game-changers around the corner?

I'd like to ask - what other critical breakthroughs would be useful as game-changers, to make a manned mission to Mars much more feasible than before?

Who are the likely sources of such breakthroughs?

Falcon Heavy is a game changer not because it is new / superior technology. It is seen as a breakthrough because it is built for *low cost*.

If SpaceX want to be the transportation system to Mars, then I would suggest approaching the problem in the same manner as they have done with their launch vehicles.

Take what is the current state-of-the-art (MSL), scale it up to a size where you get greatest demand (e.g. supplying a surface base), substitute some technologies for others (e.g. monoprop for biprop (Draco), PICA for PICA-X, etc.), figure out how to make each component cheaper, and produce them on a production line at a sufficient rate to keep marginal costs low.

Borrowing the Skycrane landing concept from MSL would allow the greatest versatility of the kind of payloads delivered to the surface: Science packages, resupply caches, inflatable habitats, large pressurized rovers - all relieved of the difficulties of having to egress from a more conventional descent stage.

FedEx for Mars.

- Mike
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Patchouli on 05/18/2011 04:00 am
Translation - advanced propulsion is pork and is to be avoided.

Well, VASIMR is a 45M project. It won't break the bank and it's very interesting. The 39 days to Mars with a 2000W/kg imaginary source, that's crazy. Many technologies are really worth investing on. In small amounts, and as fully commercial if possible. It's the multi billion monstrosities the problem. And the throw everything because in a decade we'll have something from the next 50 years.
Advanced propulsion is not pork.
There is something that can approch 2000W/kg now.
Solar has demonstrated 1000W/kg
http://www.energy-daily.com/reports/United_Solar_Ovonic_Awarded_To_Develop_New_Solarcells_For_Space_And_Airship_Applications_999.html
If an inflatable concentrator is used it just might be possible to exceed the needed 2KW per Kg at least while close to Earth.

I don't think getting similar from a molten salt core reactor is fantasy either first you need to forget about using water ie steam as the working fluid.

The higher the temperature the system operates at the smaller the radiators need to be for a given power radiating capacity.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Dave G on 05/18/2011 04:08 am
Before we go to Mars, we’ll need the equivalent of what Gemini did for Apollo.  Something that gives us the experience to perfect the systems necessary for a manned Mars mission.  Experience with low gravity, very long duration missions, and other technologies that will allow humans to survive away from Earth for years.

ISS?

Most mission plans include artificial gravity for the trip to/from Mars, but at a fraction of Earth's gravity.  Mars itself is also a fraction of Earth's gravity.

So we're talking about a 2.5 year mission, in low gravity (not zero-g), through interplanetary space, without any resupply, without the benefit of Earth's magentic field.  The space station hasn't given us experience with any of this.  A perminent moon base would give us experience with all of this, and it's only 3 days ride from Earth if something goes wrong.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: QuantumG on 05/18/2011 04:24 am
Cool.. go wake up the people who started the Moon Society and get them to start talking again....

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Michael Bloxham on 05/18/2011 04:27 am
The marginal cost would exceed the marginal benefit.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Downix on 05/18/2011 06:27 am
Translation - advanced propulsion is pork and is to be avoided.

Well, VASIMR is a 45M project. It won't break the bank and it's very interesting. The 39 days to Mars with a 2000W/kg imaginary source, that's crazy. Many technologies are really worth investing on. In small amounts, and as fully commercial if possible. It's the multi billion monstrosities the problem. And the throw everything because in a decade we'll have something from the next 50 years.
I got to thinking about this.  For 600kg, you can run a 1MW molten salt thorium reactor.  That's pretty darn close to 2000W/kg.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: QuantumG on 05/18/2011 06:55 am
Radiators.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Kaputnik on 05/18/2011 09:08 am
Been a while since I've posted here, but this is pretty exciting. And good to see Robert Zubrin himself pitching in.

A long time ago I started a thread called 'would you go to Mars now', asking the question- would you get on a Mars-bound ship created using technology developed from current or recent hardware, or would you wait until various new technologies had been developed?
It was, I thought, an informative discussion, and I drew the following conclusions:
- it is a myth that we need AG, advanced propulsion, huge in-space habitats, closed-loop ECLSS, or super-advanced electrical power systems.
- on the other hand, the problem areas are: lack of data about adaption to 0.38g and also about radiation exposure; reliability of ECLSS; Mars surface egress technology, possibly Mars surface electrical power systems, and the biggest of them all, EDLS.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: gunsandrockets on 05/18/2011 10:43 am
Friends;
I apologize for not being able to include all the details of the proposed mission plan in my WSJ op ed, which had a 1000 word limit.

In answer to some of the objections raised in this forum, you may note the following:

1. There is no need for zero gravity exposure. Artificial gravity can be provided to the crew by tethering the Dragon off the TMI stage, in the same way as is recommended in the baseline Mars Direct plan.

2. Cosmic ray radiation exposure for the crew is precisely THE SAME as that which would be received by those on any other credible Mars mission, all of which would use the 6 month Conjunction class trajectory to Mars, both because that is the point of diminishing returns (the "knee of the curve") where delta-V trades off against trip time, and because it is uniquely the trajectory that provides a 2-year free return orbit after launch from Earth. Assuming the baseline mission, the total cosmic ray dose would be no greater than that already received by a half dozen cosmonauts and astronauts who participated in long duration missions on Mir or ISS, with no radiation induced health effects having been reported. (Cosmic ray dose rates on ISS are 50% those of interplanetary space. The Earth's magnetic field does not shield effectively against cosmic rays. In fact, with a crew of 6, the current planned ISS program will inflict the equivalent of 30 man-years of interplanetary travel GCR doses on its crews over the next decade. This is an order of magnitude more than that which will be received by the crew of the mission proposed here. ) There are enough consumables on board to provide shielding against solar flares.

3. The preferred method of Mars capture is aerocapture, rather than direct entry. This means that the Dragon aeroshield, which has some lifting capability, may well be adequate. To see this with a back of the envelope calculation, consider a loaded Dragon system with an entry mass of 17000 kg, an effective shield diameter of 4 meters, a drag coeffecient of 1, coming in with an entry velocity of 6 km/s at an altitude of 33 km, where the Mars atmospheric density is 0.8 gm/m3. Setting drag equal to mass times deceleration, you can see that the system would decelerate at a speed of 42 m/s2, or a little over 4 gs. It could thus perform a 1 km/s deceleration in about 25 seconds, during which time it would travel about 140 km. This deceleration is sufficient to capture the spacecraft from an interplanetary trajectory into a loosely bound highly elliptical orbit around Mars. If the perigee is not raised, the craft will reenter again, and again, progressively lowering the apogee of its orbit, until either a desired apogee for orbital operations is achieved or the craft is committed to entry for purposes of landing. That said, if a larger aerobrake were desired, this could be created by adding either a flex-fabric or inflatable skirt to the Dragon core shield.

4. The habitable volume is admittedly lower than optimal. However it should be noted that with 5 cubic meters per crew member, it is 2.5 times higher than the 2 cubic meters per crew member possessed by Apollo crews. It could be expanded in space by the use of inflatable add-on modules. Extra space could be provided on the ground by using a 4th launch to preland another Dragon loaded with supplies, including one or more inflatable modules which could be set up by the crew after they land.

5. The mission architecture is much safer than any based on complex mega systems requiring orbital assembly, since the quality control of orbital assembly does not compare with that which can be accomplished on the ground. It would be better to have a crew of 4, but if we are to do it with Falcon 9 heavy's,  a crew of 2 is all we can do, and while it lacks a degree of redundancy otherwise desirable, it offers the counter benefit of putting the fewest number of people at risk on the first mission. It's quite true that not flying anywhere at all would be safer, but if you want to get to Mars, you have to go to Mars.

Robert

Thank you for coming to this forum and responding to the reaction to your WSJ op ed.

I'm excited by the potential of a 2 man variation of Mars Direct using Falcon Heavy launch vehicles. ;D  So I would like to add some of my own guesswork to this discussion.

Assuming all goes well for SpaceX, ten years from now there should have been multiple successful manned flights of Dragon/Falcon 9 and multiple successful unmanned flights of Falcon Heavy.  It's also reasonable to assume availability of a higher ISP Earth Departure Stage than the current Falcon 9 upper state, whether it's a SpaceX Raptor or something else.

Based on this it might be safer if the crewed Dragon launches to LEO on a Falcon 9, to rendezvous with payload launched by Falcon Heavy, for the manned outbound leg of the journey.  This would also add some extra mass to the mission budget, and perhaps even simplify payload integration of the Falcon Heavy for a relatively small extra cost.

Solar power for the manned outbound trip might be clumsy because of the conditions imposed by the free-return Mars abort scenario.  I assume that during a free-return Mars abort, the manned craft would swing way beyond Mars and deep into the asteroid belt before returning to Earth.  To accommodate how dim the sunlight is at that distance the solar panels would need to be very outsized.  Perhaps a Dynamic Isotope Power System is a better choice?

I also like the idea of the Mars surface habitat fully integrated as a two man rover, rather than giving up surface mobility because of the small mission size.  Obviously crew survival depends on successful surface rendezvous with the Ascent vehicle, so a rover is mission critical.  So rather than the crew landing on Mars in a modified Dragon capsule, they would land in the integrated habitat/rover.  The Dragon capsule should remain in a conventional Earth reentry configuration to preserve a free-return Mars abort capability for the mission.

Since in this mission design, unlike Mars Direct, the Earth Return Vehicle is already parked in orbit around Mars, perhaps the ERV could perform an additional function (though this may sound wacky :P).  Instead of the Ascent vehicle on the surface of Mars carrying it's own heavy power source, perhaps it would be easier to beam the power down from the ERV?  (I've seen a fascinating presentation last year on solar power where the idea of beaming power was presented, including a Mars mission application.)  Since the ERV is in a highly elliptical orbit around Mars it might be within direct line of sight of the Ascent vehicle most of the time.  Beamed power might allow the Ascent vehicle to evade tricky  problems presented by solar surface power or nuclear surface power.

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Nathan on 05/18/2011 11:42 am
Steven, there seems to be something wrong with that formula. Going from first principles I replicate zubrin's values.

My equation for Deceleration for a circular body in air is

a_d = 2x C_d*pi*r^2*v^2*rho/(m)

where

C_d = coefficient of drag = 1
pi = 3.14159
R=radius = 2m
v = speed = 6000 m/s
rho = air density = 0.0008 kg/m^3
m = mass = 17,000 kg


I don't have access to the reference you quoted but I cannot replicate it.
Nathan.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Dave G on 05/18/2011 12:18 pm
Been a while since I've posted here, but this is pretty exciting. And good to see Robert Zubrin himself pitching in.
Yes, I agree.

A long time ago I started a thread called 'would you go to Mars now', asking the question- would you get on a Mars-bound ship created using technology developed from current or recent hardware, or would you wait until various new technologies had been developed?
Yes, this is the essential question.  Many people seem to feel that waiting is just a way of stalling, and there's definitely merit to that argument.  A real mission always accelerates the necessary technology and systems development.

It was, I thought, an informative discussion, and I drew the following conclusions:
- it is a myth that we need AG, advanced propulsion, huge in-space habitats, closed-loop ECLSS, or super-advanced electrical power systems.
We basically have no significant data on how low gravity affects people.  It may be that a small amount of artificial gravity offers a huge benefit, especially if people strap on extra weights during exercise.  With this in mind, a tether may be unnecessary.  It's possible that just spinning the spacecraft is enough.  We need a real mission to test this.

As for advanced propulsion, it may not be necessary, but it could be a game changer.  With chemical propulsion, most of the issues have to do with the 2.5 year mission duration.  If a new propulsion system didn't have to wait for the planets to re-align, that would change everything.

Yes, huge in-space habitats are unnecessary, but spending 2.5 years in a Dragon sized capsule wouldn’t be much fun.  Something between the two seems to make more sense.

For ECLSS, I do think we'll need a closed loop system for air and water.  A partial closed loop system for food would also be nice, but you can't depend totally on that.  It would also depend on the power source.  If ample power was available for lighting, a small hydroponic plant based system to augment stored food could work well.  Plants make people happy.  In any event, life support must be robust, with multiple contingencies.

And for power, I still don't know exactly how that will work.  Solar power would be limiting, and most nuclear solutions tend to be heavy.

- on the other hand, the problem areas are: lack of data about adaption to 0.38g and also about radiation exposure; reliability of ECLSS; Mars surface egress technology, possibly Mars surface electrical power systems, and the biggest of them all, EDLS.
Agreed.  All of these are critical.

We can also test out most of this a lot closer to home, but we'll need a real mission to drive it.  That's why I believe a permanent moon base is the next logical step.

As an analogy, look at our national holidays.  We have Columbus Day, Thanksgiving, and July 4th.  In other words, the major historical events are: 1) Initial exploration, 2) Going there to stay, and 3) Independence.  Apollo gave us the equivalent of Columbus Day.  The next logical step is the equivalent of Pilgrims on the moon.  That will be historically significant, and it will give us the experience necessary to get to Mars.

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Lobo on 05/18/2011 06:12 pm

Falcon Heavy is a game changer not because it is new / superior technology. It is seen as a breakthrough because it is built for *low cost*.

If SpaceX want to be the transportation system to Mars, then I would suggest approaching the problem in the same manner as they have done with their launch vehicles.

Take what is the current state-of-the-art (MSL), scale it up to a size where you get greatest demand (e.g. supplying a surface base), substitute some technologies for others (e.g. monoprop for biprop (Draco), PICA for PICA-X, etc.), figure out how to make each component cheaper, and produce them on a production line at a sufficient rate to keep marginal costs low.

Borrowing the Skycrane landing concept from MSL would allow the greatest versatility of the kind of payloads delivered to the surface: Science packages, resupply caches, inflatable habitats, large pressurized rovers - all relieved of the difficulties of having to egress from a more conventional descent stage.

FedEx for Mars.

- Mike

To pull on this thread a little, yea, commonality, simplicity, mass-production, and lowest cost  are the keys here.  SpaceX seems like that's their mentality.

I wish I could find the link now, but I read a paper awhile back (it was from the Direct folks I think) that used aeroshells, like the NASA Mars DRA 5.0, but after entering the atmosphere, the areoshell, opens up like flower petals and turns into a rigid "parachute" to slow the payload.  I think since the petals are rigid, they can be deployed at the supersonic speeds the aeroshell will still be at at terminal velocity in the Martian atmosphere.  The aeroshell slowly opens, slowly reducing speed until it is fully opened at terminal velocity.  Then, either the rigid aeroshell/parachute is jettisoned, and the lander does a propulsive landing with thrusters on the bottom, or the thrusters are located on the aeroshell/parachute and the lander is dropped like the MSL in a maneuver similar to the skycrane.  The latter would allow your lander to be shorter and closer to the ground. 

Anyway, if such an aeroshell were developed for the FH, and perhaps made as wide as possible for the FH (SpaceX could test PLF dimensions to see how large they can get it and still safely launch to give the lander and payload designers as much volume to work with as they can.  Maybe a 6 or 6.5m wide PLF/aeroshell would be feasible.)
Then everything is just designed around those dimensions with that lift capacity.  A common lander would be disigned for all the payloads.  If the final propulsive landing was done by the aeroshell/parachute, then you'd really have a lot of flexability for your payload, as you don't really need a lander at all then.  You can drop rovers, habitats, equipment, or a crate of supplies directly on the surface.  As well as a crew lander or an ascent vehicle.
The integrated PLF/Aeroshell/rigid-parachute/skycrane sytem could be tested well ahead of a crewed mission by landing a sample return mission or very large rover (basically a robotic version of a rover a crew might use as a testbed before the crew's lives rely on it).  Or a test-bed habitat, where all internal systems could be tested for what would be the duration of a mission to see if it's design can withstand the conditions on Mars for that length of time, before the crew's lives depend on it. 
In fact, you could test the concept of making ascent propellent insitu ahead of a crew. 

But, the point being, is having a common, mass produced EDL system like that integrated PLF/aeroshell/rigid-parachute/skycrane concept, and then basing all of your Mars missions based on that. 
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Jkew on 05/18/2011 07:06 pm
Have there been any capsules designed with a movable center of gravity, so as to control the pitch a little during descent? Would this provide any useful advantage for mars entry over the disadvantage in complexity w.r.t. the dragon?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Kaputnik on 05/18/2011 07:34 pm
Have there been any capsules designed with a movable center of gravity, so as to control the pitch a little during descent? Would this provide any useful advantage for mars entry over the disadvantage in complexity w.r.t. the dragon?

With an offset CG all you have to do is control the vehicle's roll- so no moving parts, in effect. This was used on Apollo and will be used on MSL, to produce a small amount of lift enabling a more accurate landing.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Avron on 05/18/2011 08:31 pm
"American OH&S regulation wouldn't allow human Mars missions because of the radiation risk alone."

Before we go to Mars.. I would for one, like to see us manage to get any living organism to mars orbit and return it to earth..

We seem to bush off the issue of radiation and all them nice "Sun" bits and pieces that will be encountering on this little trip..

In terms of Nuke power source.. show me how you are going to cool it.. this has been covered many many times here and no answers yet..

Forget all else.. get something alive to mars and back and make sure it lives.. why worry about all the other issues.. or show me any past planetary mission that can show beyond doubt that its safe to travel.. with x or y shielding..
earth / moon stuff is within earth's influence and distance issues.. so for me it does not count..

Love SpaceX and all that..  need more proof of life after travel in this earth moon environment


 
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Robotbeat on 05/18/2011 08:37 pm
Nuke power source is not needed. Solar power is very effective, and is VERY lightweight for the power it produces (both beginning of life AND end of life performance... ahem, Mr. Downix).

As far as this quote:
"American OH&S regulation wouldn't allow human Mars missions because of the radiation risk alone."
That's ridiculous, because if astronauts were on the same regulations as terrestrial workers ("American OH&S"), no one could go to ISS for six months at a time.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: rklaehn on 05/18/2011 08:54 pm
"American OH&S regulation wouldn't allow human Mars missions because of the radiation risk alone."

Before we go to Mars.. I would for one, like to see us manage to get any living organism to mars orbit and return it to earth..

That would be a nice way to prove once and for all that radiation does not make such a mission impossible. But I think there is no reasonable doubt that two years in interplanetary space are survivable given a good solar storm shelter and some lightweight shielding (e.g. bigelow module with bags full of water attached to the walls).

Quote
We seem to bush off the issue of radiation and all them nice "Sun" bits and pieces that will be encountering on this little trip..

Every single serious mars mission concept I read about includes a "storm shelter" to survive solar flares. The cosmic background radiation will probably lead to increased cancer risk, but when you consider how dangerous such a mission will be, the mortality risk due to cancer is down in the noise.

Quote
In terms of Nuke power source.. show me how you are going to cool it.. this has been covered many many times here and no answers yet..

The key is to get a nuclear reactor that is running very hot. If you use a l liquid fluoride thorium reactor with a hot side of 1000K and cold side of 500K you only need a relatively small radiator and can still have a carnot efficiency of 50%.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: MikeAtkinson on 05/18/2011 09:01 pm
Steven, there seems to be something wrong with that formula. Going from first principles I replicate zubrin's values.

My equation for Deceleration for a circular body in air is

a_d = 2x C_d*pi*r^2*v^2*rho/(m)

where

C_d = coefficient of drag = 1
pi = 3.14159
R=radius = 2m
v = speed = 6000 m/s
rho = air density = 0.0008 kg/m^3
m = mass = 17,000 kg


I don't have access to the reference you quoted but I cannot replicate it.
Nathan.

The formula for drag is

Fd = -1/2  rho v^2 A C_d

where:
Fd = drag
rho = air density = 0.0008 kg/m^3
v = speed = 6000 m/s
A is cross-section area
C_d = coefficient of drag = 1

Which when divided by mass to get acceleration is the same formula as Steven gave.

Refs http://en.wikipedia.org/wiki/Drag_%28physics%29 (http://en.wikipedia.org/wiki/Drag_%28physics%29)
http://www.engineeringtoolbox.com/drag-coefficient-d_627.html (http://www.engineeringtoolbox.com/drag-coefficient-d_627.html)
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Nathan on 05/18/2011 10:13 pm
Ok thanks mike.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Nathan on 05/18/2011 10:30 pm
http://www.marssociety.org/home/press/news/theuseofspacexhardwaretoaccomplishnear-termhumanmarsmission

This link is on the mars society website. It describes a auxiliary aerobrake to perform moi so it could presumably be sized to do the job even with the calculation error above.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: gunsandrockets on 05/19/2011 08:48 am
http://www.marssociety.org/home/press/news/theuseofspacexhardwaretoaccomplishnear-termhumanmarsmission

This link is on the mars society website. It describes a auxiliary aerobrake to perform moi so it could presumably be sized to do the job even with the calculation error above.

Just finished reading.  Thanx for the link! :)

One thing I note is a light rover is included. (I assume something very limited like the Apollo rover)  Better hope the Dragon lands almost within walking distance of the MAV, or else the crew won't make it back home.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: gunsandrockets on 05/19/2011 09:09 am
Been a while since I've posted here, but this is pretty exciting. And good to see Robert Zubrin himself pitching in.

A long time ago I started a thread called 'would you go to Mars now', asking the question- would you get on a Mars-bound ship created using technology developed from current or recent hardware, or would you wait until various new technologies had been developed?
It was, I thought, an informative discussion, and I drew the following conclusions:
- it is a myth that we need AG, advanced propulsion, huge in-space habitats, closed-loop ECLSS, or super-advanced electrical power systems.
- on the other hand, the problem areas are: lack of data about adaption to 0.38g and also about radiation exposure; reliability of ECLSS; Mars surface egress technology, possibly Mars surface electrical power systems, and the biggest of them all, EDLS.

I agree with you.  Though I think EDLS problems I've read of have been  exaggerated by some as insoluble.
 
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Michael Bloxham on 05/19/2011 09:59 am
I also like the idea of the Mars surface habitat fully integrated as a two man rover, rather than giving up surface mobility because of the small mission size. 

Obviously crew survival depends on successful surface rendezvous with the Ascent vehicle, so a rover is mission critical. 

So rather than the crew landing on Mars in a modified Dragon capsule, they would land in the integrated habitat/rover. 

The Dragon capsule should remain in a conventional Earth reentry configuration to preserve a free-return Mars abort capability for the mission.

All good points. Perhaps the MSL EDL system could be scaled up to the size needed to deliver something like NASAs SEV rover concept? That was sized for a crew of 2.

The Curiosity rover is ~1 tonne. The SEV is aimed at ~3 tonnes (but is only designed for short-durations).

There is even an in-space version that could serve well as the ERV if a Dragon capsule is packaged within the same aeroshell (for aerocapture into Mars orbit).

- Mike
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: 2552 on 05/19/2011 10:31 am
"American OH&S regulation wouldn't allow human Mars missions because of the radiation risk alone."

Before we go to Mars.. I would for one, like to see us manage to get any living organism to mars orbit and return it to earth..

We seem to bush off the issue of radiation and all them nice "Sun" bits and pieces that will be encountering on this little trip..

The Russian Phobos-Grunt sample return mission launching later this year will do just that, via the Planetary Society's LIFE experiment (http://www.planetary.org/programs/projects/life/).

Edit: I guess not.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Avron on 05/19/2011 01:06 pm
"American OH&S regulation wouldn't allow human Mars missions because of the radiation risk alone."

Before we go to Mars.. I would for one, like to see us manage to get any living organism to mars orbit and return it to earth..

We seem to bush off the issue of radiation and all them nice "Sun" bits and pieces that will be encountering on this little trip..

The Russian Phobos-Grunt sample return mission launching later this year will do just that, via the Planetary Society's LIFE experiment (http://www.planetary.org/programs/projects/life/).

Great, then we may have some data to do some real planning
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Robotbeat on 05/19/2011 07:04 pm
"American OH&S regulation wouldn't allow human Mars missions because of the radiation risk alone."

Before we go to Mars.. I would for one, like to see us manage to get any living organism to mars orbit and return it to earth..

We seem to bush off the issue of radiation and all them nice "Sun" bits and pieces that will be encountering on this little trip..

The Russian Phobos-Grunt sample return mission launching later this year will do just that, via the Planetary Society's LIFE experiment (http://www.planetary.org/programs/projects/life/).

Great, then we may have some data to do some real planning
Um, we already have data:
http://en.wikipedia.org/wiki/Mars_Radiation_Environment_Experiment
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Avron on 05/19/2011 07:19 pm
"American OH&S regulation wouldn't allow human Mars missions because of the radiation risk alone."

Before we go to Mars.. I would for one, like to see us manage to get any living organism to mars orbit and return it to earth..

We seem to bush off the issue of radiation and all them nice "Sun" bits and pieces that will be encountering on this little trip..

The Russian Phobos-Grunt sample return mission launching later this year will do just that, via the Planetary Society's LIFE experiment (http://www.planetary.org/programs/projects/life/).

Great, then we may have some data to do some real planning
Um, we already have data:
http://en.wikipedia.org/wiki/Mars_Radiation_Environment_Experiment

Its  a box, its not alive.. its limited in what it can record.. today AMS was placed  on the ISS to look for a subset of particles that are found in earths environment.. its still will not tell us how a living organism will do in interplanetary space..  Russian Phobos-Grunt will be a better guide
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Robotbeat on 05/19/2011 07:35 pm
Okay, you asked for data. To be honest, sending a living organism isn't necessary to show the environmental conditions necessary for human spaceflight, given our current understanding... it's more ritual than science, in my opinion.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: baldusi on 05/19/2011 07:43 pm
Okay, you asked for data. To be honest, sending a living organism isn't necessary to show the environmental conditions necessary for human spaceflight, given our current understanding... it's more ritual than science, in my opinion.
There's zero investigation on the true damage of radiation to the human body. Much less of variations within humans, nor drugs to treat it. The model assumed is a threshold model, where the probability is dependent on the lifetime accumulation of radiation.
The truth is that anecdotal evidence point more towards a certain amount that humans can be exposed to continuously without any effect (and said amount is not known). And there's zero knowledge of how health hazards increase after that. A model is assumed. And then they use Hiroshima, Nagasaki and Chernobil victims. But for what's in the middle? Zero. 
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Avron on 05/19/2011 08:11 pm
Okay, you asked for data. To be honest, sending a living organism isn't necessary to show the environmental conditions necessary for human spaceflight, given our current understanding... it's more ritual than science, in my opinion.


Thanks for the link, I did not know or recall them flying the experiment, however, it did give us some data before it "fried"/stopped working.. 2.5 times ISS with 50 plus during solar SME's..
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Robotbeat on 05/19/2011 09:59 pm
Okay, you asked for data. To be honest, sending a living organism isn't necessary to show the environmental conditions necessary for human spaceflight, given our current understanding... it's more ritual than science, in my opinion.


Thanks for the link, I did not know or recall them flying the experiment, however, it did give us some data before it "fried"/stopped working.. 2.5 times ISS with 50 plus during solar SME's..
Use actual figures. The 2.5 times ISS already includes solar particle events and is only the average over a short period... The average over a longer period gives only ~2x ISS dose. If we are talking about radiation dose and the cancer risk rate using the Linear-No-Threshold model (and the LNT is very flawed, I believe and misleading... but our cancer statistics all assume it), then (assuming you never exceed an amount needed for acute radiation poisoning... which takes roughly 1000 mSv--aka 1 Sv...) you only care about the average radiation dose. The solar flares don't come into the equation (for cancer with LNT model) except how they effect the average radiation dose.

And the average measured daily radiation dose in Mars orbit with no shielding is about 1.07 mSv, or about 37 cSv per year (annual limit is 50 cSv for astronauts, I believe). A good fraction of that can be reduced with targeted shielding, though not eliminated. The dose on the surface of Mars from GCR is about 13-8 cSv per year (with no extra shielding) depending on the solar cycle (less GCR during solar max), though at lower altitudes, like Hellas Impact Basin--my favorite spot for a Mars mission--the dose will be less because the atmosphere is about twice as thick. A couple of intense solar flares would add a little bit to the total amount of radiation on the Mars surface (~1-2 cSv per flare), but these are rare, and when using the LNT model, you only care about the AVERAGE radiation (a probability of a probability), which means their contribution to radiation risk is exceedingly small once a minimum amount of shielding is available in a storm shelter for the transit (though other risks, like unshielded electronics failure in deep space, is actually NOT insignificant!).
http://www.solarstorms.org/NASATech3300.pdf

(BTW, the "2.5x ISS dose" is during a short period of solar activity of a couple months or so. Over a longer time period, it's just a little over 2x ISS's dose, as you can see from the attached.)


EDIT:Also, note that the figures are for "Radiation Dose-Equivalent at Skin Level", which is going to be a higher dose than the actual BFO dose. And even a little bit of shielding will reduce that dose.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Kaputnik on 05/20/2011 08:18 am
I'd fogotten abou MARIE- very interesting.
Should be borne in mind that a Mars crew would spend two thirds of their mission on the Martian surface, where a smaller radiation dose should be achievable, through the combination of the planet shielding them from half the sky, the presence of an atmosphere, and perhaps also regolith piled up around their habitat as has been sugested by numerous mission planners.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: madscientist197 on 05/20/2011 08:48 am
There's zero investigation on the true damage of radiation to the human body. Much less of variations within humans, nor drugs to treat it. The model assumed is a threshold model, where the probability is dependent on the lifetime accumulation of radiation.
The truth is that anecdotal evidence point more towards a certain amount that humans can be exposed to continuously without any effect (and said amount is not known). And there's zero knowledge of how health hazards increase after that. A model is assumed. And then they use Hiroshima, Nagasaki and Chernobil victims. But for what's in the middle? Zero. 

Surely there must be some animal experiments to fill in the gaps?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Dave G on 05/20/2011 11:23 am
Should be borne in mind that a Mars crew would spend two thirds of their mission on the Martian surface, where a smaller radiation dose should be achievable ...

My limited understanding is this:  There are different types of harmful radiation in space.  On the Earth, some types of radiation that would penetrate our atmosphere are blocked by our magentic field.  There is no magentic field on Mars, at least nothing significant.  Same for the moon.

Also, for the trip to Mars, there may be other dangers, such a micro-meteroids.

So it seems there needs to be different types of shields for different types of dangers.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Lampyridae on 05/20/2011 12:08 pm
Okay, you asked for data. To be honest, sending a living organism isn't necessary to show the environmental conditions necessary for human spaceflight, given our current understanding... it's more ritual than science, in my opinion.
There's zero investigation on the true damage of radiation to the human body. Much less of variations within humans, nor drugs to treat it. The model assumed is a threshold model, where the probability is dependent on the lifetime accumulation of radiation.
The truth is that anecdotal evidence point more towards a certain amount that humans can be exposed to continuously without any effect (and said amount is not known). And there's zero knowledge of how health hazards increase after that. A model is assumed. And then they use Hiroshima, Nagasaki and Chernobil victims. But for what's in the middle? Zero. 

Anecdotal evidence is not evidence. The truth of the matter is that studies produce contradictory results. There's too much experimental noise: going for more chest x-rays may just mean you're generally a less healthy person and more likely to develop cancer.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Nathan on 05/20/2011 09:38 pm
I notice dr zubrin has altered his calculation in the link above to move thru a denser part of the atmosphere. Ship has entry velocity of 6km/s at 25km altitude and atmospheric density is 1.6gm/m3.
I presume that the dragons heat shield can take this?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Robotbeat on 05/20/2011 10:05 pm
I notice dr zubrin has altered his calculation in the link above to move thru a denser part of the atmosphere. Ship has entry velocity of 6km/s at 25km altitude and atmospheric density is 1.6gm/m3.
I presume that the dragons heat shield can take this?
Landing in Hellas Impact Basin! :)

I think that's the best spot for the first human foothold on the Red Planet. Most likely chance for liquid water (pressure is above the triple point of water), least radiation, easiest EDL, easy access to buried glaciers... My favorite spot on Mars.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Nathan on 05/20/2011 10:33 pm
I notice dr zubrin has altered his calculation in the link above to move thru a denser part of the atmosphere. Ship has entry velocity of 6km/s at 25km altitude and atmospheric density is 1.6gm/m3.
I presume that the dragons heat shield can take this?
Landing in Hellas Impact Basin! :)

I think that's the best spot for the first human foothold on the Red Planet. Most likely chance for liquid water (pressure is above the triple point of water), least radiation, easiest EDL, easy access to buried glaciers... My favorite spot on Mars

Any particular coordinates? I would go for the east coast near the valley networks. Though the colles would be interesting to chech out.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: ARD on 05/21/2011 04:48 pm
Should be borne in mind that a Mars crew would spend two thirds of their mission on the Martian surface, where a smaller radiation dose should be achievable ...

My limited understanding is this:  There are different types of harmful radiation in space.  On the Earth, some types of radiation that would penetrate our atmosphere are blocked by our magentic field.  There is no magentic field on Mars, at least nothing significant.  Same for the moon.

Also, for the trip to Mars, there may be other dangers, such a micro-meteroids.

So it seems there needs to be different types of shields for different types of dangers.

The earth's atmosphere and the earth itself do a lot more to block cosmic radiation than the magnetic field does.  The magnetic field primarily blocks solar flares, which can be a danger to a Mars-bound crew.  However, solar flares can be stopped by a suitable amount of matter of any sort.  The best methods I've heard of are to simply place one's consumables and the bulk of his ship between him and the sun.  Dr. Zubrin's figures (taken from The Case for Mars) say that a two-person Mars-bound capsule (assuming they'll also keep consumables aboard if they need to abort the landing) will carry around 3.5 tonnes of consumables.  This should work as shielding on the way to Mars, if one puts all of it on the same side of the spacecraft. 

Cosmic rays cannot be stopped without many meters of dense shielding, which would make a mission excessively heavy.  These are typically stopped by the earth's atmosphere, and so are only a danger to high-altitude pilots and astronauts.  The earth's magnetic field doesn't really do much to stop these.  In Low Earth Orbit, the ISS astronauts get a bit less than half the cosmic ray dose they would get in interplanetary space, but that's more because of the earth being so close and its sheer bulk blocking those rays.  On the Martian surface itself, astronauts regain the benefit of having a planet beneath them that blocks half the cosmic radiation, and an atmosphere that reduces the damage of remaining cosmic rays.  However, as this atmosphere is thinner than that of earth, it will be beneficial to cover the habitats with regolith upon arriving.  Given that humans have gone 15 months nonstop on Mir without showing any great radiation poisoning, I'd say that cosmic rays aren't a real threat to a Mars mission. 

Regarding the use of the Dragon as a landing craft, SpaceX has released promotional videos in which a standard-looking Dragon lands on Mars using parachutes and its landing thrusters.  Does that mean they've cleared the Dragon for Mars EDL on its own, with some modifications?  Or would it need a bigger aerobrake which is jettisoned at a higher altitude? 
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: starsilk on 05/21/2011 06:39 pm
The best methods I've heard of are to simply place one's consumables and the bulk of his ship between him and the sun.  Dr. Zubrin's figures (taken from The Case for Mars) say that a two-person Mars-bound capsule (assuming they'll also keep consumables aboard if they need to abort the landing) will carry around 3.5 tonnes of consumables.  This should work as shielding on the way to Mars, if one puts all of it on the same side of the spacecraft. 

Dr Zubrin also recommends placing the mission consumables on the other end of a long tether and spinning the pair up to provide 'gravity'. the two are not mutually compatible... and even if some bulk is kept with the astronauts, spinning would make it difficult to hide 'behind'.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: guru on 05/21/2011 07:06 pm

Dr Zubrin also recommends placing the mission consumables on the other end of a long tether and spinning the pair up to provide 'gravity'. the two are not mutually compatible... and even if some bulk is kept with the astronauts, spinning would make it difficult to hide 'behind'.

No.  Zubrin's Mars Direct places an empty 30 tonne HLV upper stage on the other end of a tether.  The consumables would stay with the crew in the habitat.

The supplies are placed by the outer walls of the ship (as well as around the central core), so spinning wouldn't affect the amount of protection available, and even you did put all of the supplies on one side, the vehicle-tether-upper-stage system could be oriented so that spinning occurs about an axis normal to the direction from the sun.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: gunsandrockets on 05/23/2011 05:26 am
I also like the idea of the Mars surface habitat fully integrated as a two man rover, rather than giving up surface mobility because of the small mission size. 

Obviously crew survival depends on successful surface rendezvous with the Ascent vehicle, so a rover is mission critical. 

So rather than the crew landing on Mars in a modified Dragon capsule, they would land in the integrated habitat/rover. 

The Dragon capsule should remain in a conventional Earth reentry configuration to preserve a free-return Mars abort capability for the mission.

All good points. Perhaps the MSL EDL system could be scaled up to the size needed to deliver something like NASAs SEV rover concept? That was sized for a crew of 2.

The Curiosity rover is ~1 tonne. The SEV is aimed at ~3 tonnes (but is only designed for short-durations).

There is even an in-space version that could serve well as the ERV if a Dragon capsule is packaged within the same aeroshell (for aerocapture into Mars orbit).

- Mike

If the goal is to land a payload of about 10,000 kg on Mars, I think the SEV rover is too small and the MSL method of EDL could not scale up to meet the needs of the heaver payload.

Ideally the same EDL would be used by the two very different Mars surface payloads, the Mars Ascent Vehicle and the combo hab/rover.  What form that EDL might take I could only guess at.  What is certain is current EDL methods are apparently inadequate.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20100017668_2010017622.pdf 



Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: gunsandrockets on 05/23/2011 05:48 am
I notice dr zubrin has altered his calculation in the link above to move thru a denser part of the atmosphere. Ship has entry velocity of 6km/s at 25km altitude and atmospheric density is 1.6gm/m3.
I presume that the dragons heat shield can take this?
Landing in Hellas Impact Basin! :)

I think that's the best spot for the first human foothold on the Red Planet. Most likely chance for liquid water (pressure is above the triple point of water), least radiation, easiest EDL, easy access to buried glaciers... My favorite spot on Mars.

Mine too! ;D
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: gbaikie on 05/23/2011 10:58 am
Before this dissolves into a debate of technology.. and I thoroughly admit to having started that debate.. I have to say I would much rather hear people's opinions on the quotes.  Zubrin doesn't get up on stage or write for the newspapers to convince the technical audience.  In fact, I'm not terribly sure I've ever heard Zubrin say much to convince the technical audience. 

As I see it, his argument is simple: risk to astronaut life, be it immediate mission failure risk or long term health risk, is worth it to go to Mars.. and he typically goes on to say that the possibility of finding life is the best reason to go to Mars, with eventual colonization being a distant second.

How do you feel about that?  Is his "right stuff" mentality correct?  Is NASA way too cautious these days?  Or is he just shouting into the wind?

I think your question depends upon how necessary it is.
that other quote:
Choice quotes:
 "we could send expeditions to Mars at half the cost to launch a Space Shuttle flight."
What is the agreed cost of shuttle flight these days? 2 1/2 billion? More or less?

I think "how necessary" can be looked at from the cost and a comparison.
Of course if someone has 2 billion dollars and wants to kill himself going to Mars, it's not much of question. Nor is much of question if someone who is well informed of the risks would decide they want to go- it's their life.
So the question is of course about national policy- should NASA support such a mission. Or should we as the public, insist NASA adopt such a policy. I don't think it's a good idea.

I think we need real risk assessments. And since we took the risk of 1 dead in 50 with the shuttle program, I guess I would say 1 in 50 is an ok, risk. And if really necessary maybe 1 in 10. Soldiers could take these kinds of risks- not joining the military in general, but rather in some specific battle.
In other words they could choose to take level this risk for some dangerous operation- which considered necessary or worth the risk.

So in terms of national policy we do accept the idea of allowing soldier's to risk their lives. We have policy that we will risk soldiers lives to save one soldier's life- mainly due to honor and obligation for fellow soldiers.

One could argue that for national honor, a person's life may be worth a high risk of death. But it also could be disgraceful to allow a person die unnecessary for a nation's honor.
So how necessary is it?
Suppose we send crew to Mars for 100 billion or we could send a crew for 2 billion. Or different metric, saving time. [Steve Jobs apparently said something like save a few seconds in a computer start up and have millions of people using that computer, the total time saved would equal lifetimes of people.]
The amount time and money NASA has wasted, does give some creditability to the idea of taking high risks.
But suppose one comparing 2 billion to say 4 billion or 10 billion? How money is it worth over say 2 billion is it to make it less of a risk?
What about the risk of NASA killing a bunch crew and most citizens agreeing that it was reckless and unnecessary, and public deciding this "war" is too costly?

What if instead having crew endure 6 months of travel, for a bit more money the travel time could reduced to 5 months. Or how about if we spent say 20 billion dollars and got the crew to Mars in 3 or 2 months.
Why in terms of our nation is it necessary to do a dangerous mission on the cheap?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Michael Bloxham on 05/23/2011 11:46 am
What is certain is current EDL methods are apparently inadequate.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20100017668_2010017622.pdf 

*Sigh*

That paper (like many others I have read - quite sadly) starts out with the assumption that a Human mission would require over 100(!) tonnes entry-mass per piece. Which, quite frankly, is an outright ridiculous assumption. (Requiring over 300 tonnes to be delivered to LEO - per piece!)

What is much more realistic is entry masses in the 15 to 30 tonne range. That would allow surface payloads of 5 to 10 tonnes. Smaller - but still allow for a Human mission if it is split into sensibly-sized pieces which can be incrementally built-up on the surface. (A task which is aided by the use of mobile payloads.)

I believe such a smaller and more realistic payload requirement would be deliverable by an entry vehicle utilizing largely MSL-derived EDL technologies.

(And would be much more efficient - in terms of useful payload mass to entry mass - than anything derived from the SpaceX Dragon capsule.)

- Mike
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Lobo on 05/23/2011 10:54 pm
What is certain is current EDL methods are apparently inadequate.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20100017668_2010017622.pdf 

*Sigh*

That paper (like many others I have read - quite sadly) starts out with the assumption that a Human mission would require over 100(!) tonnes entry-mass per piece. Which, quite frankly, is an outright ridiculous assumption. (Requiring over 300 tonnes to be delivered to LEO - per piece!)

What is much more realistic is entry masses in the 15 to 30 tonne range. That would allow surface payloads of 5 to 10 tonnes. Smaller - but still allow for a Human mission if it is split into sensibly-sized pieces which can be incrementally built-up on the surface. (A task which is aided by the use of mobile payloads.)

I believe such a smaller and more realistic payload requirement would be deliverable by an entry vehicle utilizing largely MSL-derived EDL technologies.

(And would be much more efficient - in terms of useful payload mass to entry mass - than anything derived from the SpaceX Dragon capsule.)

- Mike

Since this is a thread about using FH, in that vein , I'd think your point would be obviously, and studies would be need to be done evaulating criteria for landing FH-class loads on the surface.

I think you'd want to evaluated two concepts. 
1)  A single FH launch payload (EDS launches with payload)
2)  A two FH launch payload  (EDS launches on 2nd FH, docks in LEO, and then pushed the larger mass through TMI).

If Musk is to be believed, without using a new high performance hydrolox upperstage as the EDS, a single FH should be able to send about 1/4 of it's LEO capacity of 53mt through TMI.  So about 13mt.
If a high performance hydrolox EDS were used instead of the kerlox on, that performance would increase, but I don't know how much off the top of my head.

If a 2nd FH was used with 53mt fully fueled EDS to then push a 53mt payload from the 1st FH launch (or whatever payload a 53mt fueled EDS could push through TMI...that might be less than 53mt...) then you could get significantly more through TMI obviously.
But would you then be so heavy that you'd require a more exotic and expensive EDL system than a single FH launch payload would require?

That's what I think the study could tell.  Perhaps it would be cheaper, easier, and more reliable to develop a single EDL system for landing 13mt-ish payload that are the limit of what a single FH can throw, design a lander for that EDL system, and then design your equipment and payloads to fit on those landers.  But you could send a few FH's ahead of a crewed mission to land supplies, habs, rovers, power stations, etc, all with the same common EDL/lander system.
Then your crew could use a larger vehicle that might take multiple FH launches, but it would still only be -landing- a 13mt-ish payload, because that's what the existing EDL and lander system would be designed for.

Or it might be cheaper and easier to do a two-launch architecture, that way you are only expending one EDL/lander system per mission.  If the EDL system wasn't a lot more expensive because of some issue in landing 25-30mt of mass as opposed to 13-15mt.
Maybe those two EDL/lander systems would be similar in price, maybe the larger one would be an order of magnitude greater for various reasons.

A study could tell us those things and give an idea of which way to proceed. 
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Michael Bloxham on 05/23/2011 11:08 pm
Lobo, I like the way you think ;)

Re: TMI performance: If Kero/LOX is 1/4, I think LH2/LOX is closer to 1/3rd. So figure close to 17mT through TMI.

But remember, surface payload mass is only about 1/3rd of that at TMI. (And even comparatively exotic EDL tech is not capable of bettering that.)

So in the case of Kero/LOX, we would get 13mT/3 = maybe 4mT surface payload.

For LH2/LOX, we would get 17mT/3 = maybe 5.5mT surface payload.

For the case of a single spacecraft assembled from two launches of Falcon Heavy, the surface payload might be double those figures. But at that point, you would definitely be breaking out of the realm of heritage-derived EDL technologies - as you might suspect. You would also need a PLF diameter greater than what is possible for Falcon Heavy.

For the single launch case, 4mT at a time would really be stretching what is plausible for a Human mission. But I believe 5.5mT could be workable. (For example, by sending two small mobile habs, each under 6mT and with only two crew each, which could rendezvous with pre-landed assets soon after landing.)

MP4 (the mission concept I linked to on page 6) assumed 7mT surface payloads. I found that a plausible mission could possibly be conducted with only 6 launches of an LV in the class of Falcon Heavy. (It is basically a twinned-up version of Zubrins concept - except with more realistic MSL-derived EDL tech instead of using Dragon.) This concept is only BOTE, however, and could do with a finer degree of analysis.

http://forum.nasaspaceflight.com/index.php?topic=25132.msg737905#msg737905

- Mike
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: telomerase99 on 05/24/2011 06:03 am
http://www.washingtonpost.com/national/science/one-way-ticket-to-mars/2011/05/13/AFI6L49G_story_1.html

Apparently one way to mars got thousands of volunteers. I think that this architecture would be good to sell as a one way to Mars type of approach, with a earth return vehicle added for emergency or just in case they want to come home.

Atleast if they sent a couple of people who were not opposed to staying there forever, it wouldn't be as big of a catastrophe of the earth return vehicle was too far from where they landed to use, was damaged on landing, or malfunctioned some how.

I think it is important that they have plenty of inflatables to grow there own food so that they could theoretically stay for long enough to get regular resupply shipments from earth but be robust enough to skip a shipment should the shipments be lost in transit.

If the USPS can lose a package from time to time across the country, even an experienced spacex of the future could lose a shipment of astronaut icecream in transit to mars.

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: gbaikie on 05/24/2011 07:22 am

MP4 (the mission concept I linked to on page 6) assumed 7mT surface payloads. I found that a plausible mission could possibly be conducted with only 6 launches of an LV in the class of Falcon Heavy. (It is basically a twinned-up version of Zubrins concept - except with more realistic MSL-derived EDL tech instead of using Dragon.) This concept is only BOTE, however, and could do with a finer degree of analysis.

http://forum.nasaspaceflight.com/index.php?topic=25132.msg737905#msg737905

- Mike
It seems to me that one most expensive aspects of manned mars is the return vehicle from mars surface.
Or different way to say the same thing, if business could provide a return vehicle, then this would significantly reduce the cost a NASA Manned Mars, or anyone else sending crew to Mars.
It seems to me this return vehicle should be RLV.
But perhaps if you use two stages it might better to be expendable.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: gbaikie on 05/24/2011 07:59 am

MP4 (the mission concept I linked to on page 6) assumed 7mT surface payloads. I found that a plausible mission could possibly be conducted with only 6 launches of an LV in the class of Falcon Heavy. (It is basically a twinned-up version of Zubrins concept - except with more realistic MSL-derived EDL tech instead of using Dragon.) This concept is only BOTE, however, and could do with a finer degree of analysis.

http://forum.nasaspaceflight.com/index.php?topic=25132.msg737905#msg737905

- Mike
It seems to me that one most expensive aspects of manned mars is the return vehicle from mars surface.
Or different way to say the same thing, if business could provide a return vehicle, then this would significantly reduce the cost a NASA Manned Mars, or anyone else sending crew to Mars.
It seems to me this return vehicle should be RLV.
But perhaps if you use two stages it might better to be expendable.

Or in terms of business models, one should able make one for RLV landers/return for both Mars and/or the Moon.

Though with Mars instead one might focus on a vehicle that carry cargo and crew say around 100 km across the surface. Some vehicle that brings all the bits together in one place and taxi any crew which has landed from earth to the base.
So such a taxi/pickup truck might have delta-v of around 1 km/sec.
And have "drop tanks" and cargo/crew capacity of 2 tons.
So if needs extended range it would include the drop tanks [which fit in cargo area] thereby allowing the most range to get to crew, pick them up and return to base.
Such a vehicle would be smaller the RLV lander/return vehicle, and therefore cost less to make. This taxi would need to tele-operated from earth, though it need to be able to automatically land- and could obviously have maps of the local area. Making detailed maps could be one it's first tasks. It could have some sort of wheels on it, to allow it to "dock" with other things.
So, this taxi could get to some place within 100 km within about 10 mins, and it might take hours or days to "dock" with something
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: docmordrid on 05/24/2011 01:29 pm
TSR article .....

http://thespacereview.com/article/1850/1
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Lobo on 05/24/2011 10:38 pm
Lobo, I like the way you think ;)

Re: TMI performance: If Kero/LOX is 1/4, I think LH2/LOX is closer to 1/3rd. So figure close to 17mT through TMI.

But remember, surface payload mass is only about 1/3rd of that at TMI. (And even comparatively exotic EDL tech is not capable of bettering that.)

So in the case of Kero/LOX, we would get 13mT/3 = maybe 4mT surface payload.

For LH2/LOX, we would get 17mT/3 = maybe 5.5mT surface payload.

For the case of a single spacecraft assembled from two launches of Falcon Heavy, the surface payload might be double those figures. But at that point, you would definitely be breaking out of the realm of heritage-derived EDL technologies - as you might suspect. You would also need a PLF diameter greater than what is possible for Falcon Heavy.

For the single launch case, 4mT at a time would really be stretching what is plausible for a Human mission. But I believe 5.5mT could be workable. (For example, by sending two small mobile habs, each under 6mT and with only two crew each, which could rendezvous with pre-landed assets soon after landing.)

MP4 (the mission concept I linked to on page 6) assumed 7mT surface payloads. I found that a plausible mission could possibly be conducted with only 6 launches of an LV in the class of Falcon Heavy. (It is basically a twinned-up version of Zubrins concept - except with more realistic MSL-derived EDL tech instead of using Dragon.) This concept is only BOTE, however, and could do with a finer degree of analysis.

http://forum.nasaspaceflight.com/index.php?topic=25132.msg737905#msg737905

- Mike

Well, I think you'll probably ened to break away from heritage EDL systems anyway.  It'd be pretty hard to land a crew in 4mt or less.  Not to mention landing the Mars Ascent vehicle.  Even if you make some of your propellent insitu, you'll need a powerful power source like an isotope system.   Or a very large solar array.
If you can land in the 10-11mt range with a 2XFH architecture, then you'll have a little more room to play with.   

So, if you target that surface delivery range, then you can do a study on the best EDL systems to do it.
Myself, I really like the PLF/aeroshell/rigid parachute/sky crane integraded EDL system.  Basically, the PLF at launch is retained for the whole trip, and it designed to withstand the heating of aerocapture and initial descent into the Mars atmosphere.  That's the PLF and aeroshell parts.
Then when it reaches terminal velocity, the aeroshell begins to open slowly like petals of a flower, and the payload it teathered to it's central hub, as well as guide wires that go to each of petal tips.  As the petals deploy, the system is slowly decelerated until the petals are fully deployed, and at terminal velocity.  That's a rigid supersonic parachute.
On the hub of the supersonic parachute is fuel tanks with descent thrusters.  When the system gets close to the ground, the thrusters fire slowing the system to a rate of descent safe for touch down.  Then the EDL system flies off to the side and crashes, as it's purpose is done.  That's the skycrane portion.
The nice thing about this, is the payload isn't landed on a lander base, which it then needs to be remove from, like the MER's or Pathfinder.  It drops the payload right on the surface, so it's ready to go.  Like MSL will. 

But, some studies by people far smarter than me would need to evaluate such a system.  And inflatable decelerator or some other system might be better/cheaper/more feasible.

But, if it is feasible, I could see a 10X FH architecture.  At least at first.
2XFH = Crew Return vehicle and Mars Departure stage in Mars Orbit.
2XFH = Mars Ascent Vehicle on the Mars Surface.
2XFH = Hab lander on Mars Surface.
2XFH = Equipment lander on Mars Surface (rover, power plant, etc).
2XFH = Crew mission to Mars, and landing in a Dragon capsule modified for Mars landing.  (would probably need to be fitted with supersonic parachutes and hopefully has room for them in place of where it's normal EArth parachutes would go).

You'd want your Hab lander, MAV, and equipment lander to have wheels, so they could be moved to a more desirable location around a central base as they might not have landed with pinpoint accuracy.
You do want your crew to land pretty accurately though, near your Hab or Rover lander, so they can get to the hab.  Otherwise they'll be hoofing it, and that could be a probably if they land a little off course.
If the crew lander could have possible a small solar powered rover like the lunar rover, that could help as a contingency in case they land a little wide.

Future missions could land back at the base, and utilize the existing rovers, power, hab, etc.
So it's not 10 FH launches every time, just the first time.  After that, you can probably get by with 6 launches.

You could maybe reduce your initial launches by two if you Hab lander was integrated into a large rover.  SO they actually lived in the rover.  Maybe an inflatable hab could be included as well. 

You can also get creative. 
YOu put your Rover lander in LEO with one FH launch and it's EDS with a 2nd..  Then you launch your crew on another FH launch in the Crew Return Vehicle (you need to launch them in a Dragon with an LAS system in case of launch abort) with Mars Departure stage and dock it with it's EDS, launched on the 2nd FH launch.  Then you dock that stack with the rover lander stack in LEO and transfer the crew to the Rover.  Then you send the CRV through TMI.  The crew then does it's TMI burn in the rover.  You can do a teather like Zubin suggests with the spent EDS to generate gravity.  With the crew inhabiting the Rover (which is designed to be a Hab anyway). When the CRV gets to Mars, it aerobrakes into Mars orbit.  When the Rover gets to Mars, it descends directly to the surface.  Now, even if the crew mistakenly lands off course, and some distance from the MAV lander, it can drive it.  It's not a mission critical event.  The crew inhabits the rover and performs it's mission on the surface.  when it's time to go, they drive back to the MAV, and ascend to oribt for MOR with the CRV.  The crew transfers to the CRV...the same DRagon capsule they launched in, and performs the TEI burn to return.  The return trip could utilize Zubrins 200kg inflatable hab idea, and artificial gravity with the spend MDS if they want. 
Upon approach to Earth, the crew enters the dragon capsule, jettisons everything else, and does a propulsive return on a landing pad.

There's other things they can do to.  Brainstorming is the fun part.  ;-)
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: gunsandrockets on 05/25/2011 03:57 am
Lobo, I like the way you think ;)

Re: TMI performance: If Kero/LOX is 1/4, I think LH2/LOX is closer to 1/3rd. So figure close to 17mT through TMI.

But remember, surface payload mass is only about 1/3rd of that at TMI. (And even comparatively exotic EDL tech is not capable of bettering that.)

So in the case of Kero/LOX, we would get 13mT/3 = maybe 4mT surface payload.

For LH2/LOX, we would get 17mT/3 = maybe 5.5mT surface payload.

For the case of a single spacecraft assembled from two launches of Falcon Heavy, the surface payload might be double those figures. But at that point, you would definitely be breaking out of the realm of heritage-derived EDL technologies - as you might suspect. You would also need a PLF diameter greater than what is possible for Falcon Heavy.

For the single launch case, 4mT at a time would really be stretching what is plausible for a Human mission. But I believe 5.5mT could be workable. (For example, by sending two small mobile habs, each under 6mT and with only two crew each, which could rendezvous with pre-landed assets soon after landing.)

MP4 (the mission concept I linked to on page 6) assumed 7mT surface payloads. I found that a plausible mission could possibly be conducted with only 6 launches of an LV in the class of Falcon Heavy. (It is basically a twinned-up version of Zubrins concept - except with more realistic MSL-derived EDL tech instead of using Dragon.) This concept is only BOTE, however, and could do with a finer degree of analysis.

http://forum.nasaspaceflight.com/index.php?topic=25132.msg737905#msg737905

- Mike

I believe your estimates of payload to Mars are off.  I think the rule of thumb is that for a given mass in LEO which uses a hydrogen/oxygen Earth Departure Stage, one can deliver 1/5 of that mass in payload to the Martian surface.

See this quote from the Zubrin plan, "...Here’s how it could be done. The SpaceX Falcon-9 Heavy will have a launch capacity of 53 metric tons to low Earth orbit. This means that if a conventional hydrogen-oxygen chemical rocket upper stage were added, it could have the capability of sending about 17.5 tons on a trajectory to Mars, placing 14 tons in Mars orbit, or landing 11 tons on the Martian surface."


So a single Falcon Heavy launch equals 11 tons on Mars.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Michael Bloxham on 05/25/2011 07:02 am
I believe your estimates of payload to Mars are off.  I think the rule of thumb is that for a given mass in LEO which uses a hydrogen/oxygen Earth Departure Stage, one can deliver 1/5 of that mass in payload to the Martian surface.

See this quote from the Zubrin plan, "...Here’s how it could be done. The SpaceX Falcon-9 Heavy will have a launch capacity of 53 metric tons to low Earth orbit. This means that if a conventional hydrogen-oxygen chemical rocket upper stage were added, it could have the capability of sending about 17.5 tons on a trajectory to Mars, placing 14 tons in Mars orbit, or landing 11 tons on the Martian surface."


So a single Falcon Heavy launch equals 11 tons on Mars.

I'm sorry, but surface payload to IMLEO of 1/5th is ridiculously optimistic given what we know about orbital mechanics and the challenges of EDL.

MSL, for example, is to be launched on an Atlas 541 which has a LEO capacity of 17,443kg. As the MSL payload (the rover) itself is only 900kg, this equates to an overall mass efficiency of 900/17443 = 1/20th! No where near your 1/5th "rule of thumb".

(If you think that number is wrong, perhaps you would like to show us where some fat might be cut from the Atlas / MSL system.)

Also, MSLs entry mass is about 3257kg. So the payload to entry mass ratio is 900/3257 = 1/3.6 - close enough to 1/3rd which is the figure I offered to Lobo.

Again, Zubrins expectations for EDL are ridiculously optimistic (11/14 = 1/1.3 c.f. 1/3.6) and should not be trusted. Look at the real data.

- Mike
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Lobo on 05/25/2011 03:42 pm
Ahhhh, I found the link to the paper that Direct put out.
This is showing how the Direct 2.0 Jupiter could be used for heavy LEO payloads, lunar missions, NEO missions, and Mars Missions.

http://www.launchcomplexmodels.com/Direct/documents/IAC-08.A5.3.4.pdf

Specifically look at Page 9, the "EDL Shell Parachute" system.  This is what I'm very curious about for mars payloads.  This system, if viable, could be used for FH as well.
Then it could be "mass produced" (relatively speaking) and used for all Mars payloads.  It could be used first for large unmanned rovers and a sample return mission to test bed the concept. 
But, if viable, it's a nice way to integrate the various parts of an EDL system into one single piece of equipment. 
Instead of a PLF that's jettisoned, then an aeroshell/heatshield that's jettisoned, then a parachute that's jettisoned, then the descent engines being located on the lander, it's all on one component.
Additionally, it's nice because your payload is put directly on the surface, and not high up on top of a descent stage, like MSL will be. 
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Michael Bloxham on 05/25/2011 05:42 pm
...if viable...

Well that is the question. This is the trouble with EDL tech. It is not easy to know whether these new concepts are viable - unless you go through a very expensive design and (even more expensive) qualification effort.

That is why I suggest we stick within the box of known EDL tech as much as possible. Otherwise the debate becomes uselessly hypothetical anyway. ("With our super-duper X technology, we can do Zx10!")

With that being said, having your EDL system based off of MSL tech is not all that bad. Useful payload mass of 4 to 6 tonnes may be low in comparison to what is usually specified for a Human mission. But from what I know of EDL, a mass efficiency (payload mass to entry mass) of 1/3rd is actually pretty darn good, and mass efficiency generally decreases with higher payload masses - even when assuming exotic technolgies. Technical problems (such as convective heating) become more problematic as entry masses increase as well.

So, when it comes to negotiating the problem of EDL, smaller is most definitely better. ;)

- Mike
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Kaputnik on 05/25/2011 07:57 pm
I recently read a paper by a Finnish guy- Paton, I think- who had run some interesting simulations of Mars entry profiles. One thing I took from it was the role of lift- it's a real game changer. A significant l/d (above, say, 2) can allow a much higher ballistic coefficient, lower g-loads, and more upper atmosphere manoeuvrability, with the potential for more precise landing. A decent lifting body might even be better of transitioning straight into propulsive descent, without the need for parachutes.
It's a shame that so much work on biconics and other lifting bodies is kept under lock and key.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Michael Bloxham on 05/25/2011 08:36 pm
We may be going a little off topic here, but from what I have read the effect of increasing L/D encounters diminishing returns pretty quickly - with surface payload mass efficiency being much more reliant on the ballistic coefficient. Perhaps this is because an entry trajectory with "effective" loft can be achieved with only a medium L/D (say 0.30) - and anything beyond this just creates excess lift at the expense of much more important drag?
(Edit: Lifting bodies also require greater structural mass for a given heatshield area due to increased bending loads, etc. - making them even less mass efficient.)

To bring things back on topic, I have a couple of questions which might be worth pondering:

1. Given the difficulties of EDL, would it actually be possible to land a Dragon capsule on the surface of Mars without additional aerodynamic aids (inflatable heatshields, IADs, etc. - but with parachutes - either subsonic or supersonic)?

2. If not, what sort of aerodynamic aid would work best? (Or perhaps the solution may be to use supersonic retro-propulsion?)

- Mike
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: gbaikie on 05/25/2011 08:38 pm
I recently read a paper by a Finnish guy- Paton, I think- who had run some interesting simulations of Mars entry profiles. One thing I took from it was the role of lift- it's a real game changer. A significant l/d (above, say, 2) can allow a much higher ballistic coefficient, lower g-loads, and more upper atmosphere manoeuvrability, with the potential for more precise landing. A decent lifting body might even be better of transitioning straight into propulsive descent, without the need for parachutes.
It's a shame that so much work on biconics and other lifting bodies is kept under lock and key.

Interesting.
You know, in a free system it is very hard if not impossible to keep anything under lock and key.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: gbaikie on 05/25/2011 08:52 pm
We may be going a little off topic here, but from what I have read the effect of increasing L/D encounters diminishing returns pretty quickly - with surface payload mass efficiency being much more reliant on the ballistic coefficient. Perhaps this is because an entry trajectory with "effective" loft can be achieved with only a medium L/D (say 0.30) - and anything beyond this just creates excess lift at the expense of much more important drag?
(Edit: Lifting bodies also require greater structural mass for a given heatshield area due to increased bending loads, etc. - making them even less mass efficient.)

To bring things back on topic, I have a couple of questions which might be worth pondering:

1. Given the difficulties of EDL, would it actually be possible to land a Dragon capsule on the surface of Mars without additional aerodynamic aids (inflatable heatshields, IADs, etc. - but with parachutes - either subsonic or supersonic)?

2. If not, what sort of aerodynamic aid would work best? (Or perhaps the solution may be to use supersonic retro-propulsion?)

- Mike

Well, dragon is designed from water landing on earth.
I doubt the Russian return capsule which lands on the ground on earth, could land on Mars- and any modification which could allow this might be difficult.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: ARD on 05/25/2011 10:46 pm
We may be going a little off topic here, but from what I have read the effect of increasing L/D encounters diminishing returns pretty quickly - with surface payload mass efficiency being much more reliant on the ballistic coefficient. Perhaps this is because an entry trajectory with "effective" loft can be achieved with only a medium L/D (say 0.30) - and anything beyond this just creates excess lift at the expense of much more important drag?
(Edit: Lifting bodies also require greater structural mass for a given heatshield area due to increased bending loads, etc. - making them even less mass efficient.)

To bring things back on topic, I have a couple of questions which might be worth pondering:

1. Given the difficulties of EDL, would it actually be possible to land a Dragon capsule on the surface of Mars without additional aerodynamic aids (inflatable heatshields, IADs, etc. - but with parachutes - either subsonic or supersonic)?

2. If not, what sort of aerodynamic aid would work best? (Or perhaps the solution may be to use supersonic retro-propulsion?)

- Mike

Well, dragon is designed from water landing on earth.
I doubt the Russian return capsule which lands on the ground on earth, could land on Mars- and any modification which could allow this might be difficult.

SpaceX released a promotional video implying that Dragon is capable of a Mars landing as-is.  A bit after the one-minute mark here: http://www.youtube.com/watch?v=6p6EruPdoXY

They show a Dragon parachuting down through the Martian atmosphere before using its Draco thrusters to slow down for final landing.  It looks to be the same heat shield that the Dragon uses for Earth orbit operations: 3.6 meter diameter PICA.  At 1:16, they say that the Dragon can land on any solid surface in the solar system. 

I was thinking of contacting SpaceX to ask them about this, make sure that they're going on the record saying that Dragon can do Mars aerobraking and EDL on its own. 
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: docmordrid on 05/25/2011 10:53 pm
That's not Dragon "as-is", and it's not using the Draco's. Such landings would use the still in development LES thrusters. Call back in March 2012 to see what yhey'll be like.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: baldusi on 05/25/2011 11:04 pm
At 1:16, they say that the Dragon can land on any solid surface in the solar system.
Would they try single aerobreak in Venus? Pointless exercise, at best. But if Dragon can take that, I guess it could take anything. Of course it would crumble from the pressure seconds after slowdown.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Lobo on 05/25/2011 11:55 pm

1. Given the difficulties of EDL, would it actually be possible to land a Dragon capsule on the surface of Mars without additional aerodynamic aids (inflatable heatshields, IADs, etc. - but with parachutes - either subsonic or supersonic)?


I am almost positive you'd need some deceleration aid.  Supersonic parachutes at the very least.
If Dragon's existing parachute compartment could be enlarged enough to stow the larger parachutes required for Mars, then you could probably leave the rest the same.  Your LAS thrusters would be able to do a little more work since the weight of DRagon will be 1/3 that of it on Earth, but they have the same amount of thrust and propellant to land Dragon safely on Earth.  So that would need to be taken into consideration when calculating the surface area of the parachutes needed to slow Dragon down enough so it's thrusters can get it safely on the ground. 

It would be interesting to know how much more volume the Mars Parachutes would need folded up vs. the existing amount of volume for the Earth parachutes folded up. 
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Robotbeat on 05/25/2011 11:56 pm
Yeah, supersonic parachutes would definitely be required. Advancements in that area have the potential to improve Martian EDL capabilities.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Lobo on 05/25/2011 11:58 pm

2. If not, what sort of aerodynamic aid would work best? (Or perhaps the solution may be to use supersonic retro-propulsion?)


I'd say you'd look at supersonic parachutes first to see if they could be made adequate, as Dragon is already designed for ballistic-parachute-propulsive EDL on Earth.  If you can Adapt Dragon to carry large enough parachutes for same Mars EDL, I think that'd probably be the most straight forward and simple.  Anything else would require much more modification of Dragon, so start simple, and work out from there if simple doesn't work.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Lobo on 05/26/2011 12:11 am
...if viable...

Well that is the question. This is the trouble with EDL tech. It is not easy to know whether these new concepts are viable - unless you go through a very expensive design and (even more expensive) qualification effort.

That is why I suggest we stick within the box of known EDL tech as much as possible. Otherwise the debate becomes uselessly hypothetical anyway. ("With our super-duper X technology, we can do Zx10!")

With that being said, having your EDL system based off of MSL tech is not all that bad. Useful payload mass of 4 to 6 tonnes may be low in comparison to what is usually specified for a Human mission. But from what I know of EDL, a mass efficiency (payload mass to entry mass) of 1/3rd is actually pretty darn good, and mass efficiency generally decreases with higher payload masses - even when assuming exotic technolgies. Technical problems (such as convective heating) become more problematic as entry masses increase as well.

So, when it comes to negotiating the problem of EDL, smaller is most definitely better. ;)

- Mike

Ok, I'll bite.  How much mass is the MSL skycrane EDL system capable of landing?
As in, by just scaling up the size/engines/fuel, etc, how large can you go before that system hits it's limit and you need to move to a new system?
Can it land 5mt if scaled up?  4mt?  3mt?

It's possible if it could land a few tonnes of cargo on the surface, you could do a mission based on it, you'd just need to carpet bomb the LZ with equipment and supplies ahead of the manned mission, and the crew would have to do a lot of set up on the surface.  Which might be ok if they havea  stay of 15 months or whatever the preferrable mission length is for favorable trip velocities and travel times.
YOu'd have to be modular and things would need to be designed for surface assembly if you were limited to just a few tonnes per landing.

But I suppose you'd get your EDL system "mass produced".  ;-)
So, in that case, you might be limited by your EDL system, not the lifting ability of FH.  In which case each single FH launch would have it's EDL system and a different payload. 
And there's tricks you can do.  Like land two smaller identical rovers that could be jointed together to make one larger rover with enough room to adequately habitate a couple of astronauts.  And then if one half or the other of the rovers suffered a major malfunction, they can enter the other rover, decouple it, and drive it back to base. 
You could do an inflatable hab with an inflatabe airlock for a few tonnes I imagine.  And you could have an isotope power supply for a few tonnes (or very large bank of solar arrays)

Then you can land the crew in a Dragon.

I think the biggest problems with trying to do it with several small landings is two fold.
1)  How do you land your ascent vehicle within such a small payload limit?  A Dragon capsule (even less LAS propellent) with an ascent stage would probably put you well over your landing mass limit.

2)  What happens if some of your many payloads land off target?  Can you gather them up?  What if it's your rover that lands several km's away from your hab?  How do the astronauts get to it?
The more landings you have, the greater the chance of a mission critical landing error.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: majormajor42 on 05/26/2011 02:54 am
My point in raising the issue in the first place is that I don't see how one can separate somebody's arguments on space policy from their overall rhetoric.  You can see it on the other side of this specific discussion as well regarding Zubrin.  It's a lot of fun to debate Zubrin's latest idea on its merits, but the guy himself has zero influence on actual space policy formation in Washington because he's burned all his bridges and is considered not serious.  Thus, even his good ideas have no traction.  I was sitting in the auditorium for the Augustine Committee when Zubrin got up to talk and a reasonably well-known NASA official sitting next to me quietly said "And now it's time for the entertainment portion of our program..."  The committee was ticking a box on their checklist, but they weren't listening to what he said.

brought this over from another thread.

is there a term that defines an "anti-midas" touch? not that I'm saying that this is what Zubrin has but I wonder if, as you observed, his good ideas have no traction. Earlier I was generally wondering if Zubrin has put his stamp on Musk's idea/53MTrocket and somehow called it his own. And that might be okay if Zubrin's influence could bring something new to the table, mostly more money from Congress or other investors. Well, it seems that that isn't likely, but I'll be more than happy if I am wrong on this. But the other thing I take from your comments is that NASA and other reputable institutions and people second guess any decision that has Zubrin's backing just cause he is backing it and is perceived as being out of fashion.

So, does Zubrin's latest push have some sort of adverse effect on what SpaceX is trying to do? I would at first say yes but it seems that SpaceX is not shy to controversy. I would now guess that they welcome Zubrin's input.

What bridges has Zubrin burned? I'm not up on the history.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: gbaikie on 05/26/2011 03:42 am

1. Given the difficulties of EDL, would it actually be possible to land a Dragon capsule on the surface of Mars without additional aerodynamic aids (inflatable heatshields, IADs, etc. - but with parachutes - either subsonic or supersonic)?


I am almost positive you'd need some deceleration aid.  Supersonic parachutes at the very least.
If Dragon's existing parachute compartment could be enlarged enough to stow the larger parachutes required for Mars, then you could probably leave the rest the same.  Your LAS thrusters would be able to do a little more work since the weight of DRagon will be 1/3 that of it on Earth, but they have the same amount of thrust and propellant to land Dragon safely on Earth.  So that would need to be taken into consideration when calculating the surface area of the parachutes needed to slow Dragon down enough so it's thrusters can get it safely on the ground. 

It would be interesting to know how much more volume the Mars Parachutes would need folded up vs. the existing amount of volume for the Earth parachutes folded up. 
Searched: Advanced Supersonic Parachutes for Mars
"In 2010 the Mars Science Laboratory (MSL) Mission will deliver the most massive and scientifically capable rover to the surface of Mars. To deliver this payload, an aerodynamic decelerator is required to decelerate the entry vehicle from supersonic to subsonic speeds, in advance of propulsive descent and touchdown on Mars. The aerodynamic deceleration will be accomplished by a mortar-deployed 21.5-m Viking-type disk-gap-band parachute (DGB), and will be the largest extra-terrestrial decelerator in the history of space exploration [1]. The parachute will deploy at up to Mach 2.2 and 750 Pa, resulting in the highest load and speed experienced by a parachute on Mars. The MSL parachute extends the envelope of the existing heritage deployment space in terms of load, size and Mach number. "
http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=4526284

I was wondering what the highest velocity a supersonic parachute could deploy, so it seems somewhere around mach 2.2.
Next question I have is at what velocity does this parachute stop being effective.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Robotbeat on 05/26/2011 05:45 am
...
I was wondering what the highest velocity a supersonic parachute could deploy, so it seems somewhere around mach 2.2....
That's not the limit. I'm sure a parachute could be designed to deploy at higher velocity. It certainly wouldn't be trivial, though.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: MikeAtkinson on 05/26/2011 05:55 am

2. If not, what sort of aerodynamic aid would work best? (Or perhaps the solution may be to use supersonic retro-propulsion?)


I'd say you'd look at supersonic parachutes first to see if they could be made adequate, as Dragon is already designed for ballistic-parachute-propulsive EDL on Earth.  If you can Adapt Dragon to carry large enough parachutes for same Mars EDL, I think that'd probably be the most straight forward and simple.  Anything else would require much more modification of Dragon, so start simple, and work out from there if simple doesn't work.

My (admittedly limited) understanding of Mars EDL says that Dragon has too much mass for its heatshield area to be able to slow sufficiently to deploy supersonic parachutes.

They need to be deployed high enough that there is sufficient time to slow Dragon to sub-sonic speeds. Dragon would still then have to have enough height to do a propulsive landing.

It seems that there needs to be something to produce extra drag during the early part of the descent (ballute?) or much greater propulsive deceleration (~1000 m/s).
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Kaputnik on 05/26/2011 08:32 am
My point in raising the issue in the first place is that I don't see how one can separate somebody's arguments on space policy from their overall rhetoric.  You can see it on the other side of this specific discussion as well regarding Zubrin.  It's a lot of fun to debate Zubrin's latest idea on its merits, but the guy himself has zero influence on actual space policy formation in Washington because he's burned all his bridges and is considered not serious.  Thus, even his good ideas have no traction.  I was sitting in the auditorium for the Augustine Committee when Zubrin got up to talk and a reasonably well-known NASA official sitting next to me quietly said "And now it's time for the entertainment portion of our program..."  The committee was ticking a box on their checklist, but they weren't listening to what he said.

brought this over from another thread.

is there a term that defines an "anti-midas" touch? not that I'm saying that this is what Zubrin has but I wonder if, as you observed, his good ideas have no traction. Earlier I was generally wondering if Zubrin has put his stamp on Musk's idea/53MTrocket and somehow called it his own. And that might be okay if Zubrin's influence could bring something new to the table, mostly more money from Congress or other investors. Well, it seems that that isn't likely, but I'll be more than happy if I am wrong on this. But the other thing I take from your comments is that NASA and other reputable institutions and people second guess any decision that has Zubrin's backing just cause he is backing it and is perceived as being out of fashion.

So, does Zubrin's latest push have some sort of adverse effect on what SpaceX is trying to do? I would at first say yes but it seems that SpaceX is not shy to controversy. I would now guess that they welcome Zubrin's input.

What bridges has Zubrin burned? I'm not up on the history.


Interesting. I've always thought Zubrin's mass numbers etc seemed a bit too good to be true. Although NASA have incorporated the 'semi direct' approach into their DRMs.
I hope Zubrin's work on Sabatier reactors etc is taken seriously within NASA, at least.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Michael Bloxham on 05/26/2011 11:12 am
Ok, I'll bite.  How much mass is the MSL skycrane EDL system capable of landing?
As in, by just scaling up the size/engines/fuel, etc, how large can you go before that system hits it's limit and you need to move to a new system?
Can it land 5mt if scaled up?  4mt?  3mt?

Aeroshells, heatshields, engines, etc. can all be scaled up without too much problem. The real limit is the parachutes. While slightly higher deployment mach may be possible (I'm told up to mach 2.5 with current materials) it is much more difficult to increase their diameter - that is without both their mass and deployment time becoming excessive. Solutions to this may include clustering parachutes together (which has been done before with subsonic 'chutes but never with supersonic 'chutes, AFAIK), reefed 'chutes which increase their diameter as the mach number fallls, or staged 'chutes whereby a single supersonic 'chute is discarded once the transonic boundary has been passed and is replaced by a verly large canopy of clustered subsonic 'chutes. In any case, these solutions would probably require new qualification efforts. (Except perhaps for the latter case?)

- Mike
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Michael Bloxham on 05/26/2011 11:46 am
I think the biggest problems with trying to do it with several small landings is two fold.

1)  How do you land your ascent vehicle within such a small payload limit?  A Dragon capsule (even less LAS propellent) with an ascent stage would probably put you well over your landing mass limit.

2)  What happens if some of your many payloads land off target?  Can you gather them up?  What if it's your rover that lands several km's away from your hab?  How do the astronauts get to it?

The more landings you have, the greater the chance of a mission critical landing error.

1) Don't use Dragon. If a dedicated lander was used, greater useable payload mass can be achieved. If the Ascent vehicle uses ISRU, then a large but lightweight solar array can suffice to generate the needed propellant if given enough time (say if the Ascent vehicle is sent 2.5 years ahead of the crews arrival).

2) In MP4, I assumed two small mobile habs with two crew each. These would be solar-powered (the array area required is not too large when you consider the relatively small mass of each mobile hab - and use power-scheduling rather than storage) - thereby giving them practically unlimited range. If either one failed, then the other would come to its rescue. There was also an auxilliary unmanned mobile hab (actually a "mobile lab") which would allow even more contingency modes. The crew would land in their rovers with a month or two of consumables onboard - which should give sufficient time to access pre-landed supplies of consumables - especially given these three different options to acquire them.

Also, such multiple surface-rendezvous architectures can be designed to be sufficiently robust so that if any one lander fails (except for the crewed mobile habs), the ability remains to return the crews to Earth.

- Mike
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: MATTBLAK on 05/26/2011 12:07 pm
If approval or funding or both cannot be secured for a small true, nuclear reactor-powered ISRU package - maybe a big, efficient gallium-arsenide solar array could work in conjunction with a multiple-R.T.G. package to power the propellant plant?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Michael Bloxham on 05/26/2011 12:26 pm
How much power you need simply depends on how much time you can afford to devote to the propellant production process. If you need to generate all of the propellant within 6 months of landing, then absolutely some kind of powerful nuclear power source would be required. But if you can afford to stretch out the propellant production process to 2 years or more (e.g. by sending the ISRU plant in the window ahead of the crews arrival), then a large solar array - perhaps 500kgs worth, should be completely sufficient. Theoretically, the ISRU process could be stretched out even more: If the ISRU plant is sent in the window ahead of the crews arrival, then a total time of about 1300 days (3.5 Earth-years!) is available until the crew must use the Ascent vehicle to return to the ERV in Mars' orbit. (But then the crew is forced to wait and cannot reach the ERV earlier than scheduled - i.e. in the case of an abort-to-orbit.) RTGs might work too, but these generally produce less power for a given mass than solar arrays. Perhaps it might be prudent to have one or two small ones to provide heating and contingent power during dust storms, etc.

- Mike
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: MATTBLAK on 05/26/2011 12:34 pm
I was mainly thinking about RTGs for night. Obviously, a LOX/CH4 plant would have to throttle-down at night, but at least the percentage points of produced propellant could creep up slowly over time. The gruntiest RTG I remember reading about produced about 700W of constant power. I'll have to research (tomorrow) about what 'Curiosity's RTG will produce and then imagine a 'scale-up' or arrayed cluster of the things: RTGs produce a fair amount of power for their size & weight.

But I'm not researching it now: its 12:34 am here in Auckland and I've gotta get to bed! ;) See you maybe tomorrow, Michael and others!! :)
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Robotbeat on 05/26/2011 06:41 pm

2. If not, what sort of aerodynamic aid would work best? (Or perhaps the solution may be to use supersonic retro-propulsion?)


I'd say you'd look at supersonic parachutes first to see if they could be made adequate, as Dragon is already designed for ballistic-parachute-propulsive EDL on Earth.  If you can Adapt Dragon to carry large enough parachutes for same Mars EDL, I think that'd probably be the most straight forward and simple.  Anything else would require much more modification of Dragon, so start simple, and work out from there if simple doesn't work.

My (admittedly limited) understanding of Mars EDL says that Dragon has too much mass for its heatshield area to be able to slow sufficiently to deploy supersonic parachutes.

They need to be deployed high enough that there is sufficient time to slow Dragon to sub-sonic speeds. Dragon would still then have to have enough height to do a propulsive landing.
...
No reason Dragon couldn't start propulsive landing while still supersonic.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Lobo on 05/26/2011 07:04 pm
...
No reason Dragon couldn't start propulsive landing while still supersonic.

Yea, I thought someone said that you can fire retro rockets while supersonic.  That having to slow to subsonic before you could fire them was inaccurate?

And your fuel would last longer, since the system is designed to land the Dragon's weight on Earth.  On Mars, you could do a serious of shorter burns to slow down because you don't need all of your propellant for touchdown because of the reduced weight.

Studies by people smarter than me could look at that, then figure out how large the supersonice parachutes would need to be to slow from terminal balistic velocity to the point where Dragon can start firing it's retro rockets.  And then see if those parachutes could fit inside Dragon parachute compartment, and if not, could Dragon be feasibly modified with a larger parachute compartment to accomodate the Mars chutes?  And if not, then other EDL methods would need to be looked at.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Robotbeat on 05/26/2011 07:07 pm
I have no doubt that Dragon would need considerable modifications in any case. Parachute compartment size is probably the least of your problems.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Michael Bloxham on 05/26/2011 07:16 pm
and if not, could Dragon be feasibly modified with a larger parachute compartment to accomodate the Mars chutes?

Perhaps you could replace the CBM with a smaller port - thereby freeing up some room on top of the capsule?

I have no doubt that Dragon would need considerable modifications in any case. Parachute compartment size is probably the least of your problems.

Of course I am sure that landing a Dragon capsule on Mars would be a completely absurd undertaking. But the question has been asked - and it is quite fun to contemplate: What changes *exactly* would be required if one simply had to do it?

- Mike
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Lobo on 05/26/2011 07:20 pm


My (admittedly limited) understanding of Mars EDL says that Dragon has too much mass for its heatshield area to be able to slow sufficiently to deploy supersonic parachutes.

They need to be deployed high enough that there is sufficient time to slow Dragon to sub-sonic speeds. Dragon would still then have to have enough height to do a propulsive landing.

It seems that there needs to be something to produce extra drag during the early part of the descent (ballute?) or much greater propulsive deceleration (~1000 m/s).

Well, certainly Dragon's heatshield is too small for it's mass in the thin Martian atmosphere to sufficiently slow it during ballistic entry and descent for Earth-sized parachutes to work.  If supersonic parachutes can be deployed at around mach 2.5 (per the pots about the MSL), then the questions would be is the terminal velocity Dragon could achieve via ballistic reentry alone be over mach 2.5?  And if so, can parachutes be made to deploy at that higher speed?  And if so, how hard would that be?  And if it's too difficult, can the retro thrusters start firing at over mach 2.5 to slow Dragon down enough to deploy it's super sonic chutes, and still leave enough fuel for a safe landing?  If so, you'd still be in good shape.  If not, you'd have to look at other EDL techniques.

If there's just no way to make it work with DRagon's existing heatshield, LAS/landing system, and potential space available for supersonic parachutes, one possibility is that Dragon would likely have some sort of trunk under it to protect the heatshield and supply power, etc.  Dragon would probably be docked at it's docking port to some sort of hab module during Mars transit.  So in that trunk, if you could store a large, inflatable hypercone descelerator on a teather to the nose of Dragon, then you could deploy that when you jettison the trunk prior to entry, and that would cause a slower terminal velocity than would the heatshield alone.  The hypercone descelerator would be designed to get the terminal velocity down to around mach 2.5, where it could be jettisoned and the supersonic parachutes stowed in Dragon's parachute compartment could be deployed.  Then the final phase would be propulsive.

The advantage of that, is the inflatable hypercone doesn't need to be stowed on Dragon itself, it can be stowed in the trunk.  Dragon's already going to be very limited in mass and volume. 
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Lobo on 05/26/2011 07:33 pm
and if not, could Dragon be feasibly modified with a larger parachute compartment to accomodate the Mars chutes?

Perhaps you could replace the CBM with a smaller port - thereby freeing up some room on top of the capsule?


That's a pretty good idea.  You wouldn't need something as large as teh CBM port on DRagon, you'd only need a docking tunnel wide enough to get a single man through, like the Apollo-LEM docking tunnel.  Likely Dragon would be docked to some sort of inflatable hab module during the transit, so the astronauts would need to just be able to squeeze through there. 
Dragon has a big benefit of flexibility to it's nose, because it doesn't need to accomodate an LAS tower.  So it could be modified to have a longer nosecap during launch, which would house a narrow docking tunnel instad of the CBM, with the large, supersonic parachutes stowed around that tunnel. 
Such a concept introduces more possibilities, like a double parachute system.  First it hypersonic parachutes (would probably look like ribbons more than actual parachutes) to slow Dragon to around mach 2.5 where the Viking/MSL heritage supersonic parachutes could depoy after jettoning the hypersonic parachutes. 
Just have to make sure the docking tunnel and large parachutes weren't so heavy that the LAS system couldn't abort Dragon during launch, or return Dragon to Earth in case of a LOM malfunction while still in LEO.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Michael Bloxham on 05/26/2011 07:43 pm
Okay, does anyone here have the expertise to run this through some kind of accurate EDL simulation?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Jkew on 05/26/2011 08:11 pm


My (admittedly limited) understanding of Mars EDL says that Dragon has too much mass for its heatshield area to be able to slow sufficiently to deploy supersonic parachutes.

They need to be deployed high enough that there is sufficient time to slow Dragon to sub-sonic speeds. Dragon would still then have to have enough height to do a propulsive landing.

It seems that there needs to be something to produce extra drag during the early part of the descent (ballute?) or much greater propulsive deceleration (~1000 m/s).

... SNIP ....
If there's just no way to make it work with DRagon's existing heatshield, LAS/landing system, and potential space available for supersonic parachutes, one possibility is that Dragon would likely have some sort of trunk under it to protect the heatshield and supply power, etc.  Dragon would probably be docked at it's docking port to some sort of hab module during Mars transit.  So in that trunk, if you could store a large, inflatable hypercone descelerator on a teather to the nose of Dragon, then you could deploy that when you jettison the trunk prior to entry, and that would cause a slower terminal velocity than would the heatshield alone.  The hypercone descelerator would be designed to get the terminal velocity down to around mach 2.5, where it could be jettisoned and the supersonic parachutes stowed in Dragon's parachute compartment could be deployed.  Then the final phase would be propulsive.

The advantage of that, is the inflatable hypercone doesn't need to be stowed on Dragon itself, it can be stowed in the trunk.  Dragon's already going to be very limited in mass and volume. 

I was thinking along similar lines, but I thought the barrier between the inflatable cone and the normal dragon heat shield would be difficult to get right within some useful range of reliability. A similar idea I liked was a hard shield which could be deployed like a flower pedal around the existing shield.

...but these ideas are not evolutionary changes from the existing dragon and as far as I know SpaceX has no inflatable heat shield knowledge in house (yet).

I think a more likely path is to try propulsive deceleration above mach 2.5. The nice thing about this is that you can test it easily under a number of different scenarios including earth's atmosphere. Where do you store the extra fuel required (who knows yet)? Can the dragon hypergolic engine (would it be hypergolic ) fire reliably at these speeds (who knows)?

Also; it seems possible that a different or variable CG for mars would change the lifting characteristics enough to shave a little off the speed. I read a paper that proposed variable CG for mars entry largely for more accurate landings which I can't seem to find again. I need to reread that paper.

Since we didn't see that part of the landing in that fancy video I can only assume they haven't fully figured it out either.

Edit, here's the paper; sort of interesting:
http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/38372/1/05-1442.pdf
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Michael Bloxham on 05/26/2011 08:33 pm
I think a more likely path is to try propulsive deceleration above mach 2.5. The nice thing about this is that you can test it easily under a number of different scenarios including earth's atmosphere.

Excellent point.

Where do you store the extra fuel required (who knows yet)? Can the dragon hypergolic engine (would it be hypergolic ) fire reliably at these speeds (who knows)?
 

This was also asked by someone else. From what I know, it is incredibly difficult to *start* an engine while it is exposed to supersonic air streams. However, once started it is possible to keep it running easily enough - although it would cause aerodynamic instability unless placed around the periphery of the vehicle (as is the case of the Dragon LAS). The question I have is whether the LAS nozzles - by virtue of being within the aerodynamic shell of Dragon - would be adequately sheltered from any incoming air stream so that they are able to be lit?

Also; it seems possible that a different or variable CG for mars would change the lifting characteristics enough to shave a little off the speed. I read a paper that proposed variable CG for mars entry largely for more accurate landings which I can't seem to find again. I need to reread that paper.

Apollo and Dragon both use this, and MSL will use it also.

Edit: Didn't see your link. I'll have to read that paper, but why not just use an offset CoG and rotate your craft around like Apollo/Dragon/MSL?

Since we didn't see that part of the landing in that fancy video I can only assume they haven't fully figured it out either.

I am sure it was just a promotional video with no real basis in reality anyway. I wouldn't read too much into it.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Lobo on 05/26/2011 11:16 pm

I was thinking along similar lines, but I thought the barrier between the inflatable cone and the normal dragon heat shield would be difficult to get right within some useful range of reliability. A similar idea I liked was a hard shield which could be deployed like a flower pedal around the existing shield.


Maybe this brings us back to the EDL Shell paraachute system I talked about a few pages back.
Advantages:
1)  You have a much larger ballistic surface area of the aeroshell versus Dragon's heat shield, or even vs. a large diameter disk heat shield.  Or at least one you could feasibly launch on a FH.  So your terminal velocity is slower.

2)  You have a rigid parachute that can be deployed at supersonic speeds, probably speeds faster than soft parachutes, because you can deploy it slowly, rather than all at once.  So you can control your rate of desceleration so you don't stress you hardware as much.
(Like flower petals opening).

3)  Your propulsion for landing is on the EDL shell parachuate, so you don't need to build it into your payload.  This would allow you to drop your payload directly on the surface, rather than having a lander base with empty tanks and spent engines that the paylaod needs to get down from.  (a particularly benefit for a robotic mission so you don't have to figure out how to remotely deploy it, and then get it off it's lander base without flipping over.  The MER's and the MSL use that method, the MER's used airbags that could be deflated so the rover didn't have to drive down much of an incline, and the MSL will be dropped directly onto the surface.  Viking and Phoenix had engines on the lander, but they were stationary landers, and didn't need to be moved once landed.  Future robotic rovers and equipment for a crewed mission will likely need to be moved in some way.)

Disadvantages:

1) New tech.  Really no "heritage" tech to utilize for it, other than the skycrane system like MSL.

2)  Deployment of the aeroshell into the rigid parachute, and the payload moving from inside the aeroshell to hanging below the rigid parachute  could present some technological challenges. 

3)  You can't land your launch capsule with it, (like a Dragon) because all payload within the EDL shell parachute, when it's simply a PLF on the LV, needs to be stacked upside down on the pad, since it'll be entering Mars atmosphere  nose first.
You'd need the crew to launch in a separate vehicle, and then transfer to a lander of some type in the aeroshell at some point in space.
Obviously whatever capsule your crew launches in must be upright, and not contained in a PLF/aeroshell of any kind so it's free to use it's LAS system in case of a launch abort.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: neutrino78x on 05/30/2011 04:28 pm
I am a big fan of Robert Zubrin, although my views have changed a little since he came out with his book The Case for Mars. (http://www.amazon.com/Case-Mars-Plan-Settle-Planet/dp/145160811X/ref=sr_1_1?ie=UTF8&qid=1306772859&sr=8-1)

I now feel that government astronauts should not be asked to risk their lives just for scientific data.

The only time I would justify the government sending humans into space is for emergency rescue and/or military operations.

I think a private venture should use the Mars Direct plan to go to Mars, and claim the land for the United States, exactly the same way that Jamestown Settlement (http://en.wikipedia.org/wiki/Jamestown_settlement) was founded. We would have to modify the Outer Space Treaty, as I said in another place, to authorize that.

Also I would modify the Mars Direct plan in a couple ways: I would use solar rather than nuclear, and I would use on orbit assembly rather than wait for a heavy lift rocket. Also, he uses an internal combustion powered truck in his plan, I would use an electric vehicle.

--Brian
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: madscientist197 on 05/30/2011 05:07 pm
I now feel that government astronauts should not be asked to risk their lives just for scientific data.
Let me rephrase that: you think that government astronauts should be forbidden from volunteering for such a mission? I can assure you that they would be queuing up. Anyway, it would not merely be for scientific data, as much as some might wish it were.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: douglas100 on 05/30/2011 07:52 pm
I am a big fan of Robert Zubrin, although my views have changed a little since he came out with his book The Case for Mars. (http://www.amazon.com/Case-Mars-Plan-Settle-Planet/dp/145160811X/ref=sr_1_1?ie=UTF8&qid=1306772859&sr=8-1)
I think a private venture should use the Mars Direct plan to go to Mars, and claim the land for the United States, exactly the same way that Jamestown Settlement (http://en.wikipedia.org/wiki/Jamestown_settlement) was founded.

And who do you think is going to pay for this?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: neutrino78x on 06/02/2011 02:37 am
Quote from: neutrino78x
I think a private venture should use the Mars Direct plan to go to Mars, and claim the land for the United States, exactly the same way that Jamestown Settlement (http://en.wikipedia.org/wiki/Jamestown_settlement) was founded.
And who do you think is going to pay for this?

The people who go there will pay for it themselves, man. King James I of England didn't pay people to settle North America.

People want to settle Mars. I want to live there. Zubrin wants to live there. Others do. It will happen with or without government action.

I definitely do not think the US Government should ask astronauts to risk their lives to do something that private individuals are quite willing to do.

The US Government didn't pay people back in 1850 to come here to San Francisco; the individuals chose to come here because they wanted to get rich with gold.

Colonization is usually not something a government does, rather, people who wish to be colonists go out there and colonize.

All the government has to do is make sure it is possible to own private property on Mars, and set up some kind of trading system for private land there. Currently, it is not possible to own private property on Mars, because the Outer Space Treaty prevents it.

--Brian
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: M_Puckett on 06/02/2011 02:57 am
It does nothing of the sort.  The Outer Space Treaty is binding on soverigns, not corporations or private citizens.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: douglas100 on 06/02/2011 08:46 am
Quote from: neutrino78x
I think a private venture should use the Mars Direct plan to go to Mars, and claim the land for the United States, exactly the same way that Jamestown Settlement (http://en.wikipedia.org/wiki/Jamestown_settlement) was founded.
And who do you think is going to pay for this?

The people who go there will pay for it themselves, man. King James I of England didn't pay people to settle North America.

Your historical analogy is mostly invalid. Space colonisation is not the same as colonisation on Earth. Spaceflight is not the same as ocean voyaging, or trecks across North America. The technology to do these things had existed for hundreds of years before the people set out. The cost was such that ordinary people of modest means could attempt it.

The technology to transport people to Mars does not exist yet. The means to support a large scale settlement on Mars do not exist yet. The degree of difficulty and the cost of the enterprise are enormous compared with the wealth of the average citizen.

Don't expect a private colony on Mars any time soon.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Dave G on 06/02/2011 11:48 am
Your historical analogy is mostly invalid. Space colonisation is not the same as colonisation on Earth.
I think a historical analogy is quite appropriate, but let's look at the whole analogy.  For example, look at our national holidays.  We have Columbus Day, Thanksgiving, and July 4th.  Those represent the 3 major historical events:
1) Exploration
2) Colonization
3) Independence

Exploration is usually funded by governments.  Colonization follows exploration, and is often privately funded, but not always.

We've already explored the Moon, so for many people, the next logical step is to explore Mars.  The only problem is that a Mars mission currently looks a lot like colonization.  It would last 2 1/2 years, with most of that spent on the Mars surface.  By the time you have technology mature enough to risk almost 2 years on another planet, you've not far from staying there permanently.

That's why I favor going to the moon before Mars.  We should set up a permanent moon base.  That will allow us to perfect systems robust enough to risk a 2-year mission on another planet, and if anything goes wrong, Earth is only 3 days away.

Of course, this all assumes a Mars mission would use current types of propulsion.  If a new propulsion technology allowed a much shorter Mars mission, that would be more like exploration, perhaps a few months total mission duration.  But that requires something fast enough to chase Earth's orbit, so that you don't have to wait for the planets to re-align in order to get home.  We don't have that yet.

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Jim on 06/02/2011 12:04 pm
I am a big fan of Robert Zubrin, although my views have changed a little since he came out with his book The Case for Mars. (http://www.amazon.com/Case-Mars-Plan-Settle-Planet/dp/145160811X/ref=sr_1_1?ie=UTF8&qid=1306772859&sr=8-1)
I think a private venture should use the Mars Direct plan to go to Mars, and claim the land for the United States, exactly the same way that Jamestown Settlement (http://en.wikipedia.org/wiki/Jamestown_settlement) was founded.

And who do you think is going to pay for this?

Not any gov't
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: MATTBLAK on 06/02/2011 12:54 pm
The best any Govt. involvement could hope for would be as a partner, and possibly only a small-to-medium sized one at that. Like, if the Govt. put $2 billion towards the project as seed money, but many other Private Investors, Consortiums and altruists follow through with the bulk of the costs and risks - and score most of the gains, if any (small-to-modest) to be reaped.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: douglas100 on 06/02/2011 01:13 pm

Exploration is usually funded by governments.  Colonization follows exploration, and is often privately funded, but not always.

That's correct, of course. And the exploration of Mars has been under way since 1965.

The idea I was arguing against is the assertion that there are a few super rich individuals out there who are going to found a private colony on Mars "just like the Jamestown settlement" and claim "the land." Nothing like that is going to happen until technology and wealth reach a point where a genuine space faring civilisation  is established and transport off this planet is cheap enough for the average citizen. In other words, no time soon.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Lobo on 06/02/2011 06:31 pm
Quote from: neutrino78x
I think a private venture should use the Mars Direct plan to go to Mars, and claim the land for the United States, exactly the same way that Jamestown Settlement (http://en.wikipedia.org/wiki/Jamestown_settlement) was founded.
And who do you think is going to pay for this?

The people who go there will pay for it themselves, man. King James I of England didn't pay people to settle North America.

Your historical analogy is mostly invalid. Space colonisation is not the same as colonisation on Earth. Spaceflight is not the same as ocean voyaging, or trecks across North America. The technology to do these things had existed for hundreds of years before the people set out. The cost was such that ordinary people of modest means could attempt it.

The technology to transport people to Mars does not exist yet. The means to support a large scale settlement on Mars do not exist yet. The degree of difficulty and the cost of the enterprise are enormous compared with the wealth of the average citizen.

Don't expect a private colony on Mars any time soon.

YEa, I have to concur here.

Other than the basic "flavor" of it, there's not much similarity.
Yea, in both cases you have bold explorer's heading out into the great unknown.  But the similarities end after that.

To make Mars colonization similar to American colonization, here's how it'd have to be different than it currently is:

1)  You would be able to take off from Earth, transit to Mars, and land all in the same vehicle.  The American colonists used the same vessel to launch from port, transit, and land in the New World.

2)  You would be able to utilize ambient energy for your launch, transit, and landing.  You wouldn't need to carry ANY propellent with you.  The American colonists used wind power the whole trip. 

3)  While you would need to bring food and water with you on the transit, you wouldn't need to bring air or gravity with you.  (if you wanted artificial gravity to be sure your pioneers wouldn't be too atrophied to be useful on the mission).

4)  Once you got to Mars, you know you could find your own food, water, air, fuel, and building materials.  (even if food might be scarce...it -would- be there for foraging)

5)  Your spaceship and provisions would only cost a few million dollars in today's dollars.  (allowing rich private individuals to fund some expeditions, or governments to be able to afford to fund several expeditions.)

6)  And you might throw in there the ability to operate in the outdoors without the need for space suits or pressurized habs.  But since we have much better tech/maps/communications than we did 500 years ago, I'll give the benefit of the doubt and say the technological challengeds they faced 500 years ago in finding their way around unexplored land (with no maps from satellites), evading hostile natives, suffering harsh winters, and building shelters, tools, clothing, equipment from the land would be similar to modern astronauts having to operate in space suits and pressurized habitats and vehicles. 
So I'll call #6 a wash.

I mean, yea, they didn't know what was there 500 years ago, but they DID know a few things would be there for sure.  Food, water, air, and timber.  If all of that was available on Mars, well then we'd probably have been there back in the 70's.  BEcause even though people were loosing interest in going to the Moon, there's be enough private and public interest in going to Mars if #1-#5 above were applicable.

IF you needed to have taken 5 ships with you to explore Ameriacn 500 years ago, 4 of them emptry.  1 to get out of port in Europe, 1 for the transit accross the atlantic, one to land on the shore (yes, I realize they had longboats for actual landing, but they were reusable, a Mars lander would not be), one to get back to the ocean, one for transit (you could use the same ship that you used for the first transit possibly), and one to land back in Europe.
And if those trips cost the equivalent of several BILLION dollars
And if those first explorers needed to bring all of their fuel with them (or at least most of their fuel).
And all of their provisions for both trips and the stay there needed to be brought with them.  And there was no chance of any privisions being available anywhere in the New World.

Then, the Americas might never have been colonized...  Maybe a couple of exploration expeditions eventually for scientific study, but that might have been it.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: RanulfC on 06/02/2011 08:16 pm
I think a private venture should use the Mars Direct plan to go to Mars, and claim the land for the United States, exactly the same way that Jamestown Settlement (http://en.wikipedia.org/wiki/Jamestown_settlement) was founded. We would have to modify the Outer Space Treaty, as I said in another place, to authorize that.
Ok... But before you go to "far" with that let me ask the pertinant question?
Which "Jamestown" are we speaking of? The original which was to rely on the local inhabitents for food and supplies while being a port from which English raiders could attack Spanish gold shipments from?

Or the SECOND one which was moved from its original location to one where the colonists could actually farm and aquire local supplies and actually managed to survive unlike the first?

Note that BOTH were "private" ventures, one of which was planned MUCH better than the other....

Also, regarding the OST it does NOT "regulate" in any way private or corporate "ownership" or use of outer-space materials, that would be the 1979 "Moon-Treaty" which was NOT ratified in the US (among several dozen OTHER nations which ARE signators of the original OST) and therefore holds no legal status with US citizens or enterprises.
(Now if you are going to the Moon from Australia, you've got some major issues :) )

The OST PRECLUDES any "Nation-State" from "claiming" territory in space, this is true, (ensureing that America could not claim the "Moon" as the 51st state) this means that the United States (or any other) Government can NOT 'hand-out' leases or sell "territory" as is common on Earth AND makes any nation responsible for the actions or effects of any spacecraft or personnel launched from their territory.

But in EFFECT it means that no "claims" to outer-space territory can be valid since no "government" can legally back those claims, however in effect neither can any claims be legally challenged either :)

This gray area has lead to several attempts at "claiming" outer-space territory by both scam artists AND legitimate people using the loop-holes created. Examples would include at least TWO people who have filed "titles" the entire Moon, and the fellow who tried to charge NASA with "parking-fees" because he "owned" the asteroid Eros :)

In any discussion I've seen on the subject "legally" the only acceptable way to "own" territory in space is to physically OCCUPY that space. This precludes the use of "drones" or "robots" and such things as planted flags but having PEOPLE "on-site" pretty much ensures they "own" the site.

I've never really understood WHY this seems so hard to understand.

Randy
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: RanulfC on 06/02/2011 08:25 pm
2)  Deployment of the aeroshell into the rigid parachute, and the payload moving from inside the aeroshell to hanging below the rigid parachute  could present some technological challenges. 

3)  You can't land your launch capsule with it, (like a Dragon) because all payload within the EDL shell parachute, when it's simply a PLF on the LV, needs to be stacked upside down on the pad, since it'll be entering Mars atmosphere  nose first.
You'd need the crew to launch in a separate vehicle, and then transfer to a lander of some type in the aeroshell at some point in space.
Obviously whatever capsule your crew launches in must be upright, and not contained in a PLF/aeroshell of any kind so it's free to use it's LAS system in case of a launch abort.
I wanted to point out that you actually DON'T 'stack' everything upside down in the DIRECT concept though it's hard to tell HOW it's done. Since the EDL-Fairing is actually a "biconic-lifting-body" it would enter on it's "side" and the "lander" would deploy out the aft end at some point which is where that illustration gets VERY funky :)

I'm "guessing" that illustration #2 is actually a 'side-view' of the sides of the fairing 'inverted' as they open so that you're looking at one "petal"?
No, that can't be right because you can see the "landing-legs" sticking up towards the nose in figure #1...

Now I'm even MORE confused :)

Randy
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Lobo on 06/03/2011 12:13 am
2)  Deployment of the aeroshell into the rigid parachute, and the payload moving from inside the aeroshell to hanging below the rigid parachute  could present some technological challenges. 

3)  You can't land your launch capsule with it, (like a Dragon) because all payload within the EDL shell parachute, when it's simply a PLF on the LV, needs to be stacked upside down on the pad, since it'll be entering Mars atmosphere  nose first.
You'd need the crew to launch in a separate vehicle, and then transfer to a lander of some type in the aeroshell at some point in space.
Obviously whatever capsule your crew launches in must be upright, and not contained in a PLF/aeroshell of any kind so it's free to use it's LAS system in case of a launch abort.
I wanted to point out that you actually DON'T 'stack' everything upside down in the DIRECT concept though it's hard to tell HOW it's done. Since the EDL-Fairing is actually a "biconic-lifting-body" it would enter on it's "side" and the "lander" would deploy out the aft end at some point which is where that illustration gets VERY funky :)

I'm "guessing" that illustration #2 is actually a 'side-view' of the sides of the fairing 'inverted' as they open so that you're looking at one "petal"?
No, that can't be right because you can see the "landing-legs" sticking up towards the nose in figure #1...

Now I'm even MORE confused :)

Randy

http://www.launchcomplexmodels.com/Direct/documents/IAC-08.A5.3.4.pdf

Yea, it gets a little grey there of how they get from Figure 1 to Figure 2 on page 9. 
YEs, I agree that Figure 2 shows 3 of the 4 "petals", two edge on, one side on, with the 4th petal being hidden by the side-on petal nearest us.  Similar to how the Saturn V 3rd stage petals opened up to reveal the LEM.  So using that reference, imagine the Saturn IVB stage, wiht a nose cap where the Apollo CSM sat, plunging into the Martian atmosphere on it's side nose first.  Once terminal velocity has been reached, the petals start to open, but unlike Saturn, the tips of the petals are connected to the lander with guide wires (to keep them from being ripped off in by the slip stream).  As the petals start to open, the "Saturn IVB" stage will pull back from the lander due to higher drag than the lander itself has.  You might picture that phase as a drogue chute deployed to orient the APollo capsule properly prior to the deployment of the main chutes, and to help pull them out.  Except instead of there being a main parachute, the EDL Shell parachute slowly opens, creating more and more drag.  Until it's fully opened for maximum drag, with the lander hanging below it as in Figure 3. 
To do that, I'm pretty sure you'd need your lander to be stacked upside down at launch.  And in figure 1, it seems to show the lander's feet in the nosecap.  (although these are just rough sketches).
If the lander was stacked right side up in the EDL Shell parachute, it'd have to sort of slide out behind the EDL Shell after terminal velocity, then it'd have to somehow invert so that it was infront of the EDL Shell parachute.  Which might be difficult if not impossible to do while supersonic.

But, there's really no reason you can't stack the lander upside down is there?
This would be the lander and part of a a larger mission.  The crew would launch in a Dragon capsule, and then transfer to this lander at some point during the transit.  Probably viat some docking maneuver from the back of the areoshell/EDL parachute, since you probably couldn't dock anywhere on the EDL shell without compromising it.  Maybe on the side that would be opposite the rentry, and thus it won't see bad heating loads, and perhaps could be built with a docking hatch of some sort. 
But likely you'd dock from the back of the EDL shell.  And that would be pretty easy, because if the lander is stacked upside down in the shell, with the feet pointing towards the nose.  Then the lander could be easily built with a docking hatch on it's top that'd connect to the "back" of the EDL shell, and a docking tunnell could be build in the "back" of the EDL shell, so that one side it docked with the lander, and the other side could be docked to the.  Take Figure 1, and dock the nose of a Dragon CSM into the rear end of it for crew transfer. 
The back of the EDL Shell parachute system would have obviously hinges, structural supports, fuel tanks, and landing thrusters all built into it, which is why I say you would want to design a docking tunnel through it.  Upon entry to Mars, the lander sould stay docked to the back of the EDL shell until the petals started to open, then it'd undock and let the EDL shell pull back from it due to it's higher drag, thus deploying  the lander.

And, since this is a FH thread and not a Direct Thread, we'd assume a FH based system would have a smaller EDL shell system obviously.  And you could do something like, instead of a purpose built lander, you could put another Dragon bare capsule in the EDL Shell.  With it's nose docked to the tunnel at the back of the EDL Shell.  (So it would be upside down at launch).  The launch Dragon (or some other type of Mars Transfer vehicle) would dock at the back of the EDL shell, and the crew would transfer into the Mars Descent Dragon.  The Mars Descent DRagon could be modified with a minimal heat shield, or no heat shield, and no LAS thrusters or fuel, as the EDL shell performs all of those tasks.  It could have an equipment trunk of some kind in it's place.  And that might be nice for a Lunar Rover type of vehicle, just in case the crew land several km's from the hab and equipemnt which would have been landed in advance of the mission.
A nice contingency plan just in case. 

But a purpose built lander might be a better option.  They can do studies to figure that out.  :-)
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Kaputnik on 06/03/2011 08:52 am
Sorry if this was discussed and I've missed it, but in an attempt to get this thread back on topic, what sort of PLF diameter has Musk proposed for FH?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: docmordrid on 06/03/2011 09:01 am
Standard is 5.2 meters, but the FH page also says "Custom fairings are available at incremental cost."
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Lobo on 06/03/2011 05:01 pm
Standard is 5.2 meters, but the FH page also says "Custom fairings are available at incremental cost."

Anything over 5.2m would require testing and perhaps individual test flight to qualify.  To make sure it didn't actually buckle the barrel in a real world launch before you put a multi-million dollar payload on it.

Steve Peitrobon said he thought with the 3.6m Falcon barrel, you could probably go as high as about 6.5m PLF.  He said there's never been a PLF twice as wide as the barrel, but there have been some around 80% larger.  So going with that, that gets you around 6.4 or 6.5m PLF.
Anything above that, you are into brand new territory for rocket design.
And it's not like you can't go larger, as long as you test it, and maybe strengthen the core, but, just has a SWAG, you -should- be able to go to around 6.4m PLF without getting into a a whole new mess of headaches.

And although this is a FH-Mars thread.  I really like the FX, and potential variants for going to Mars.  If for no other reason, than you should be able to get up to about a 10m PLF with an FX, FXH, or potential FXSH-5 core variant.  And a 10m PLF gives you a lot of flexibility with your mission and vehicles.  IT's what the Ares V was planned to have. 
FH could still be used for lunar missions in the more near term.  As they are less complex than Mars Missions will be, and you can do short-stay lunar missions.  You really can't do a short stay Mars Mission.

The FX can give you around 38mt to LEO as a single stick.  90-100mt to LEO as a 3-core heavy (non-cross feed).  And 120-125mt as a 3-core heavy (cross feed).  A 5-core design should be you pushing 200mt.
And the wider core would allow you to put a PLF large enough on it to utilize that lifting capability volume-wise. 
That leaves a gap in the performance range with SpaceX, but if they kept the F9 and FH going  (FX would need whole new launch pads anyway, so they could keep launching F9 and FH at Vandenberg & LC-40.).  And then that gives you a 16mt (to LEO) launcher (F9), a 38mt launcher (FX), a 53mt launcher (FH), a 90-100ish mt launch (FXH non-crossfeed), a 120-125mt launcher (FXH cross feed) and a 180-200mt launcher (FXSH 5-core) if such a beasty was every desired).
If they contracted with NASA for use of the VAB and pad 39B (assuming a clean pad design), and built a MLP that could launch an FX, and FXH, and designed to be expanded to a 5-core FXSH if the need ever arised, then they could launch those from there. 
SpaceX probably wouldn't need to launch FX's from Vandenberg because the F9 and FH would give them 16-53mt paylaod capacity for polar orbits, and I'd assume that's as much as you'd need for polar orbit payloads, which will likely be satellites smaller than 53mt.
So basing the FX out of LC-39 should work out for them.  Anything launched on an FXH or FXSH would likely be NASA exploration payloads anyway, so there'd be an additional benefit of operating out of NASA's launch complex and stacking in their VAB.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: neutrino78x on 06/04/2011 03:45 am
Which "Jamestown" are we speaking of? The original which was to rely on the local inhabitents for food and supplies while being a port from which English raiders could attack Spanish gold shipments from?

Or the SECOND one which was moved from its original location to one where the colonists could actually farm and aquire local supplies and actually managed to survive unlike the first?

It is up to the colonists, since the government would not be in control of the mission, but I would imagine the second example would be closer to what they do. Especially since Zubrin and myself advance the idea of ISRU, using the resources of the environment, instead of waiting for the building of Enterprise NCC-1701 before before going to Mars.

Quote
Note that BOTH were "private" ventures, one of which was planned MUCH better than the other....

And neither of which was planned by James I or his Government.

Quote
Also, regarding the OST it does NOT "regulate" in any way private or corporate "ownership" or use of outer-space materials,

True, but it does seem to prohibit ownership of celestial bodies.

Quote
The OST PRECLUDES any "Nation-State" from "claiming" territory in space, this is true, (ensureing that America could not claim the "Moon" as the 51st state)

Rather, insuring that neither the USA nor the USSR would use the Moon as a nuclear weapons platform.

Quote
this means that the United States (or any other) Government can NOT 'hand-out' leases or sell "territory" as is common on Earth [...]

But in EFFECT it means that no "claims" to outer-space territory can be valid since no "government" can legally back those claims,

Exactly. Therein lies the problem. Claims to land on Mars need to be valid. Thus the OST should be modified.

Quote
In any discussion I've seen on the subject "legally" the only acceptable way to "own" territory in space is to physically OCCUPY that space. This precludes the use of "drones" or "robots" and such things as planted flags but having PEOPLE "on-site" pretty much ensures they "own" the site.

Yeah, people who don't work for the government. Individuals should be the ones who colonize, not the government. Science can be done with drones.

--Brian
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: RanulfC on 06/06/2011 02:16 pm
Which "Jamestown" are we speaking of? The original which was to rely on the local inhabitents for food and supplies while being a port from which English raiders could attack Spanish gold shipments from?

Or the SECOND one which was moved from its original location to one where the colonists could actually farm and aquire local supplies and actually managed to survive unlike the first?

It is up to the colonists, since the government would not be in control of the mission, but I would imagine the second example would be closer to what they do. Especially since Zubrin and myself advance the idea of ISRU, using the resources of the environment, instead of waiting for the building of Enterprise NCC-1701 before before going to Mars.

Quote
Note that BOTH were "private" ventures, one of which was planned MUCH better than the other....

And neither of which was planned by James I or his Government.
::::sigh:::: You missed the point... BOTH were the SAME "colony" paid for by private investment but SUPPORTED by James 1 AND the Government who provided both the "land" and the original contracts which ALLOWED the venture to take place. IF they hadn't "approved" it never would have happened.

The "government" OWNED the land! They had to "sell" it to the COMPANY which then "sold" it to the colonists. This is how ALL land/property on Earth has worked, and the OST simply says that GOVERNMENTS can NOT claim "space" or any celestial body simply by landing in one place and planting a flag. They are to be "secured" by the various national-governments but not OWNED by them.

Quote
Also, regarding the OST it does NOT "regulate" in any way private or corporate "ownership" or use of outer-space materials,
Quote
True, but it does seem to prohibit ownership of celestial bodies.
You keep asserting that but it's not true.
Quote
The OST PRECLUDES any "Nation-State" from "claiming" territory in space, this is true, (ensureing that America could not claim the "Moon" as the 51st state)
Quote
Rather, insuring that neither the USA nor the USSR would use the Moon as a nuclear weapons platform.
Actually the "No Nuclear Weapons in Outer Space" part was aimed at preventing orbital nuclear weapons platforms not putting nukes on the Moon as that wasn't ever a really "viable" concept. And no, the meaning was QUITE clear: No "colonization" by anexation of outer space as was done on Earth.
Quote
this means that the United States (or any other) Government can NOT 'hand-out' leases or sell "territory" as is common on Earth [...]

But in EFFECT it means that no "claims" to outer-space territory can be valid since no "government" can legally back those claims,
Quote
Exactly. Therein lies the problem. Claims to land on Mars need to be valid. Thus the OST should be modified.

Modification was TRIED, and we ended up with the 1979 Treaty which SPECIFICALLY forbids ANY private "ownership" of space or any outer-space body AND also specifically regulates any and all "profit" made from outer-space activities or endevour to be distributed to ALL the people on the Earth.... Ya, THAT was "better" wasn't it.

So your argument then is that Earth governments must anex and then distribute all possible "property" in Outer-Space the same way they do on Earth? That is the only "valid" claim to property you know, it's only "valid" is someone, somewhere, at some point BOUGHT it from the "government" who's contention is that the OWN all land/property on Earth?

Quote
In any discussion I've seen on the subject "legally" the only acceptable way to "own" territory in space is to physically OCCUPY that space. This precludes the use of "drones" or "robots" and such things as planted flags but having PEOPLE "on-site" pretty much ensures they "own" the site.
Quote
Yeah, people who don't work for the government. Individuals should be the ones who colonize, not the government. Science can be done with drones.
According to your OWN argument the "government" has to in fact "claim" and "own" the territory first and THEN "sell" it to those who colonize. THAT is the "valid" way that it works here on Earth and you wish to apply that to outer space?

In terms of someone going to Mars and claiming the territory they "settle" on, that's perfectly LEGAL under the OST. (Totally "illegal" under the 1979-Moon Treaty) They just can't lay claim to the whole planet NOR can any government should they get there first. Nothing prevents a person or company from engaging in colonizing, resource extraction, or any other profitable enterprise in outer space, nor does it restrict how those profits or anything else is to be distributed.

Randy
(Edit: Better? I hope :)
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: QuantumG on 06/06/2011 11:37 pm
Please do edit the quoting on that.. I can't tell where your words end and his start.

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: neutrino78x on 06/08/2011 05:30 am
Quote from: RanulfC
Quote from: neutrino78x
And neither of which was planned by James I or his Government.


::::sigh:::: You missed the point... BOTH were the SAME "colony" paid for by private investment but SUPPORTED by James 1 AND the Government who provided both the "land" and the original contracts which ALLOWED the venture to take place. IF they hadn't "approved" it never would have happened.

The "government" OWNED the land! They had to "sell" it to the COMPANY which then "sold" it to the colonists. This is how ALL land/property on Earth has worked, and the OST simply says that GOVERNMENTS can NOT claim "space" or any celestial body simply by landing in one place and planting a flag. They are to be "secured" by the various national-governments but not OWNED by them.

okay...so you seem to agree with me that James I allowed the London Company to use his land, claimed in his name, and owned by him. Yet, you are endorsing the OST, which would say that James I cannot own land.

Quote from: RanulfC
So your argument then is that Earth governments must anex and then distribute all possible "property" in Outer-Space the same way they do on Earth? That is the only "valid" claim to property you know, it's only "valid" is someone, somewhere, at some point BOUGHT it from the "government" who's contention is that the OWN all land/property on Earth?

That is certainly the way it is traditionally done, yes.

For example, the USA got the Louisiana Purchase, and allowed US citizens to buy and sell land within it. They could do this because it was now US soil.

I would argue that potential settlers would want to know that they can have an undisputed claim to land on Mars or an asteroid, and the best way to do that is to have some kind of legal regime to confirm claims.

I do admit that the traditional way for a nation to claim property would be to have a human standing on it. But, back then, there was no such thing as a remotely operated probe, and there certainly wasn't space travel. I guess have mixed feelings and nuanced feelings on the topic. :-)

--Brian
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: douglas100 on 06/08/2011 07:56 am
I think this discussion of property rights etc. is almost irrelevant while there is little prospect in the near future of humans traveling to Mars. Zubrin's proposal, which is the topic of this thread, isn't going to land a party of private individuals on Mars.

I'll repeat what I said earlier: analogies between historical colonisation and the settlement of Mars or any other Solar System body should not be taken very far. Space flight is enormously more difficult and expensive (at the present time) than crossing the Atlantic was in the Seventeenth Century. The future will be different from the past.

Zubrin has had some good ideas in the past and is a charismatic guy, but if he is claiming that we could go to Mars for "the price of a Shuttle flight" then he has lost it. Look at some of the early posts on this thread: I think calling them sceptical is a reasonable description.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Lobo on 06/09/2011 04:33 am
I think this discussion of property rights etc. is almost irrelevant while there is little prospect in the near future of humans traveling to Mars. Zubrin's proposal, which is the topic of this thread, isn't going to land a party of private individuals on Mars.

I'll repeat what I said earlier: analogies between historical colonisation and the settlement of Mars or any other Solar System body should not be taken very far. Space flight is enormously more difficult and expensive (at the present time) than crossing the Atlantic was in the Seventeenth Century. The future will be different from the past.

Zubrin has had some good ideas in the past and is a charismatic guy, but if he is claiming that we could go to Mars for "the price of a Shuttle flight" then he has lost it. Look at some of the early posts on this thread: I think calling them sceptical is a reasonable description.

X2
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: RanulfC on 06/09/2011 11:49 pm
I think this discussion of property rights etc. is almost irrelevant while there is little prospect in the near future of humans traveling to Mars. Zubrin's proposal, which is the topic of this thread, isn't going to land a party of private individuals on Mars.
Quote from: Lobo
X2
Spoilsports :P
Quote from: douglas100
I'll repeat what I said earlier: analogies between historical colonisation and the settlement of Mars or any other Solar System body should not be taken very far. Space flight is enormously more difficult and expensive (at the present time) than crossing the Atlantic was in the Seventeenth Century. The future will be different from the past.

Zubrin has had some good ideas in the past and is a charismatic guy, but if he is claiming that we could go to Mars for "the price of a Shuttle flight" then he has lost it. Look at some of the early posts on this thread: I think calling them sceptical is a reasonable description.
It seems that anologies of ANYTHING done on Earth releated towards Space only go so far, and never as far as those who get caught up in the argument (guilty! :) ) tend to want them to go...

But in relation to the actual subject of the thread itself I agree that skeptisism is warrented.

Randy
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: DaveH62 on 06/10/2011 01:49 am
Quote from: Lobo
X2
Spoilsports :P
Quote from: douglas100
I'll repeat what I said earlier: analogies between historical colonisation and the settlement of Mars or any other Solar System body should not be taken very far. Space flight is enormously more difficult and expensive (at the present time) than crossing the Atlantic was in the Seventeenth Century. The future will be different from the past.

Zubrin has had some good ideas in the past and is a charismatic guy, but if he is claiming that we could go to Mars for "the price of a Shuttle flight" then he has lost it. Look at some of the early posts on this thread: I think calling them sceptical is a reasonable description.
Quote
It seems that anologies of ANYTHING done on Earth releated towards Space only go so far, and never as far as those who get caught up in the argument (guilty! :) ) tend to want them to go...

But in relation to the actual subject of the thread itself I agree that skeptisism is warrented.

Randy

Would it be feasible to go with a process along the lines of the US Homestead policy of giving land to any settler that occupied and settled the land. It limited a site to 40 acres and provided a legal umbrella for a mass migration. The cost of going to the Moon or Mars is far greater, so the reward would need to be much higher. What if any entity (nation, corporation, person) were given rights to say a 40 square mile area upon establishing a settlement, including all mineral and orbital landing rights. This would equalize nations, corporations, non-profits and individuals. Anyone with a plan and a pocketbook would have an incentive. 
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Patchouli on 06/10/2011 01:52 am
Quote from: Lobo
X2
Spoilsports :P
Quote from: douglas100
I'll repeat what I said earlier: analogies between historical colonisation and the settlement of Mars or any other Solar System body should not be taken very far. Space flight is enormously more difficult and expensive (at the present time) than crossing the Atlantic was in the Seventeenth Century. The future will be different from the past.

Zubrin has had some good ideas in the past and is a charismatic guy, but if he is claiming that we could go to Mars for "the price of a Shuttle flight" then he has lost it. Look at some of the early posts on this thread: I think calling them sceptical is a reasonable description.
Quote
It seems that anologies of ANYTHING done on Earth releated towards Space only go so far, and never as far as those who get caught up in the argument (guilty! :) ) tend to want them to go...

But in relation to the actual subject of the thread itself I agree that skeptisism is warrented.

Randy

Would it be feasible to go with a process along the lines of the US Homestead policy of giving land to any settler that occupied and settled the land. It limited a site to 40 acres and provided a legal umbrella for a mass migration. The cost of going to the Moon or Mars is far greater, so the reward would need to be much higher. What if any entity (nation, corporation, person) were given rights to say a 40 square mile area upon establishing a settlement, including all mineral and orbital landing rights. This would equalize nations, corporations, non-profits and individuals. Anyone with a plan and a pocketbook would have an incentive. 

I like that concept keep so no one entity can own an entire celestial body but allow one to own the immediate region around where they place a mine or colony.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: neutrino78x on 06/10/2011 05:45 am
(this thread might properly belong in Space Policy section...)

I have to admit, my feelings are somewhat mixed on this.

Like I said, originally, when I first read Zubrin's book The Case for Mars, back when it came out in 1998, when I was 20 and in community college, I really thought that what we should do is a manned NASA mission to Mars, with the intention of having civilian colonizers come to live on the base, supported by NASA. In other words, NASA would build infrastructure on Mars, and civilians would be the ones who are living there as colonists (and by civilians I mean, not government employees but actual civilians).

But, since then, we have seen that it takes NASA forever to even build a Space Station. A seemingly simple Mars Sample Return mission still has not been done. One would think they could use that as a demo for ISRU propellent production, but apparently not. NASA's robotic space program is enormously successful, but that is not true of HSF since Apollo. This is partially because of lack of direction from various Presidential Administrations, but still, it shouldn't take 20 years to decide on a space vehicle to build, and then build it.

In contrast, look at how much has been done by SpaceX, with only 2000 or so employees!!! Plus, as I've said so many times, here on Earth, on the High Seas, most ships are civilian. The US Navy didn't exist when the nation was founded; it was only when our ships were attacked that we established a US Navy.

This is what lead me to look at how we settled North America, which is what Zubrin discusses a lot in his book. He talks about NASA setting up the initial infrastructure, but is that how we did it with North America? Actually, it is not. The people who started Jamestown Settlement were just normal civilians, although the leader was a former Royal Navy captain. From what I can ascertain, he was not a Navy captain at the time, but retired, and just an employee of London Company, which was a private company.

The biggest issue with my new position, of course, is that the reason the British had that land in their control such that they could give it to London Company is that they landed a Navy unit in North America in the past. So, would NASA have to land men on Mars before The Mars Society could go there and credibly claim land? I don't know.

I do think that, however it is done, I would want the US Constitution to apply to US colonies until such time as they declared independence.

I also am convinced that we should not land NASA astronauts on Mars unless we have a clear path to getting civilians to follow, otherwise it is just a science mission, and we could have done that with robots. I felt that way in 1998 too, the main difference is that today, I am not sure that NASA should be the first there at all.

--Brian
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: douglas100 on 06/10/2011 08:06 am
From RanulfC:

Quote
It seems that anologies of ANYTHING done on Earth releated towards Space only go so far, and never as far as those who get caught up in the argument (guilty!  ) tend to want them to go...

Agreed.

From DaveH62:

Quote
I like that concept keep so no one entity can own an entire celestial body but allow one to own the immediate region around where they place a mine or colony.

Yes, this makes sense. It's difficult to imagine one nation or group claiming all of Mars. No one else would recognise the claim.

From neutrino78x:

Quote
But, since then, we have seen that it takes NASA forever to even build a Space Station. A seemingly simple Mars Sample Return mission still has not been done.

First of all NASA didn't build the International Space Station by itself. One of the reasons it was delayed was the Columbia accident. Secondly nothing about landing on Mars is "simple," never mind a Mars sample return mission.

Zubrin's idea for an ISRU sample return mission sounds good in principle but it not necessarily in practice. That's one of the things I've learned from this forum: there is no "simple" when it comes to spaceflight.

I think Mars will be settled but I would not venture to say how or when. I hope it happens in your lifetime. It will most certainly not happen in mine. That's the thing about the future: it never turns out as you expect.

Space is a new medium. Historical analogies are suspect (I'm repeating myself, sorry.) Be patient.

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: yamato on 06/10/2011 08:09 am
do you want to help colonize mars? get rich! :)
in my point of view, human spaceflight will soon turn into a private enterprise. National space agencies (not just NASA) are showing their uneficiency, enormous financial and byrocratic burden, lack of leadership that is connected with EVERY governmental administration. Space exploration needs innovation, lots of money, but also guts for enormous risks. You can get it from state agency in time of war, given unlimited budget and an army of test pilots. But you will never get it from state agency in time of peace, limited budget and no pressure for results. We hear about plans for mars in "about 20 years from now" since 1980´s. What has been done? Nothing. NASA is loosing even it´s ability to get to LEO, Russians are flying on the 1960´s soyuz and Europe did never even develope it´s own capsule.
So I think the enormous desire to explore other worlds will be satisfied by rich private enthusiats. Their funds, combined with the emerging HSF commercial market, will make things finally happen. 
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: douglas100 on 06/10/2011 02:01 pm
do you want to help colonize mars? get rich! :)

So I think the enormous desire to explore other worlds will be satisfied by rich private enthusiats. Their funds, combined with the emerging HSF commercial market, will make things finally happen. 

Maybe. If you could name some super rich individuals who will put up billions of their own money for this enterprise (not a few hundred million, as Musk has), I might start to take it seriously.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: DaveH62 on 06/10/2011 03:22 pm
do you want to help colonize mars? get rich! :)

So I think the enormous desire to explore other worlds will be satisfied by rich private enthusiats. Their funds, combined with the emerging HSF commercial market, will make things finally happen. 

Maybe. If you could name some super rich individuals who will put up billions of their own money for this enterprise (not a few hundred million, as Musk has), I might start to take it seriously.
Colonize by countries, corporations or individuals can only work with some sustainable economic model. Science and national defense can drive the dialog to some degree, but there must be some profit somewhere. Early options are for someone like James Cameron to do a blockbuster 3d movie. Spend 500 million and make a billion for a lunar movie, reboot and do it again. Tourism: There are over 1000 billionaires and nearly 20 million millionaires in the world. There should be a market for a few orbital tourist missions a year, and maybe even some Edmund Hillary type person who would want to be explore the moon or Mars and spend a few hundred million to do it.
Beyond that, property rights that encourage exploration and development of assets and a NASA policy that encourages private sector collaboration. Going beyond CCDev, NASA should have a commercial development team that would only get project go ahead if they can on board commercial partners. Hey Exxon/Rio Tinto, help us with a lunar base station to explore for minerals or energy (H3).
This is not rocket science, but it requires some lateral thinking, and it needs to be articulated so the legal and lobbyist entities can get busy with important and productive work, instead of getting involved in technical rocket design issues.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: 2552 on 06/28/2011 02:39 am
http://www.thespaceshow.com/newsletterfinal.htm

Quote
2. The Tuesday, June 28, 2011 7-8:30- PM PDT program welcomes back Dr. Robert Zubrin to discuss his latest plans for enabling manned missions to Mars.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: 2552 on 06/29/2011 11:00 pm
Here's the archive link for Tuesday's Space Show:

http://archived.thespaceshow.com/shows/1583-BWB-2011-06-28.mp3

Discussion of SpaceX and Falcon Heavy/Dragon for Mars missions begins at 15:30
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: catiare on 07/07/2011 03:19 am
In that interview, Dr. Zubrin mentions an inflatable structure attached to the Dragon. Can a Bigelow Sundance be used in this case? Meaning stacked to a Dragon as the habitat in transit to Mars?. If it would, then the argument that the dragon is too small for a crew of two for a Mars trip would be a moot point. As per the Bigelow's website, the Sundance is fully equipped for a long durations stays "including lavatory and hygiene facilities.".
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Jason1701 on 07/07/2011 01:18 pm
In that interview, Dr. Zubrin mentions an inflatable structure attached to the Dragon. Can a Bigelow Sundance be used in this case? Meaning stacked to a Dragon as the habitat in transit to Mars?. If it would, then the argument that the dragon is too small for a crew of two for a Mars trip would be a moot point. As per the Bigelow's website, the Sundance is fully equipped for a long durations stays "including lavatory and hygiene facilities.".

A Sundancer could be used, but Dr. Zubrin is wrong when he says that it could be stored in the Dragon's trunk. It would require a dedicated launch with the standard fairing.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: jabe on 07/07/2011 01:30 pm
I think zubrin is thinking of a simple inflatable "tent" that mounts on the front.  No solid core,  just a room to stretch out .  But that is my interpretation.  I did enjoy that spaceshow.  With zubrin seems to have black or white view... A bit harsh but he does make some good points

Jb
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: go4mars on 07/07/2011 03:17 pm
In that interview, Dr. Zubrin mentions an inflatable structure attached to the Dragon. Can a Bigelow Sundance be used in this case? Meaning stacked to a Dragon as the habitat in transit to Mars?. If it would, then the argument that the dragon is too small for a crew of two for a Mars trip would be a moot point. As per the Bigelow's website, the Sundance is fully equipped for a long durations stays "including lavatory and hygiene facilities.".

A Sundancer could be used, but Dr. Zubrin is wrong when he says that it could be stored in the Dragon's trunk. It would require a dedicated launch with the standard fairing.

There is a 34 m^3 trunk version that I think would fit. Versions that are larger yet are possible also.  As to mass, I believe that a FH launch should handle it.  Raptor upper stage wouldn't hurt either.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Dave G on 07/07/2011 05:12 pm
A Sundancer could be used, but Dr. Zubrin is wrong when he says that it could be stored in the Dragon's trunk. It would require a dedicated launch with the standard fairing.

Zubrin is saying we can do the semi-direct manned mission to Mars for just a few billion total.  An extra FH launch would be another $100 million, a small percentage more.  At this point, that's in the noise.

If Zubrin is off and the total mission costs are much higher, like tens of billions, then an extra FH launch is even more in the noise.

If SpaceX is off and their FH ends up costing a lot more than $100 million, then all bets are off.

The underlying point here is that low launch costs are the key for doing a manned mars mission, which is what Musk said when he formed SpaceX.  Unless we get into some new cold war, that's the only way a mars mission will ever happen.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: catiare on 07/08/2011 02:10 am
Dr. Zubrin also mentions a 1-Mile tether to create artificial gravity. How much weight would a 1-Mile cable add to the to whole system?

My point is if the artificial gravity really necessary? Astronauts have stayed for more than 6 months at a time, the bone loss and other medical issues are known but that does not prevent from staying today at zero gravity on the ISS. I'm not an expert but that rotation maneuver sounds kind of risky and probably unnecessary on a Generation 1 mission. I see this as improvements for subsequent generations of interplanetary vessels.

Also the argument of Dragon being too small can be solved by attaching a Sundancer to it.

So I guess it comes down to Spacex fulfilling the promise of a cheap launch vehicle and a capable capsule.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: neutrino78x on 07/08/2011 03:32 am
Dr. Zubrin also mentions a 1-Mile tether to create artificial gravity. How much weight would a 1-Mile cable add to the to whole system?

I haven't heard the interview yet, but to get 1 G with 1 RPM, you would have to use a 894 meter cable, which is only 2933 feet. In the book The Case for Mars, Zubrin talks about 6 RPM, which would not need such a long cable.

Click on this link (http://www.cthreepo.com/lab/math1.shtml), in the artificial gravity section (2nd from top), put in 1 and select Minutes for the rotation rate, and put in 1 G for the amount of gravity to simulate, it will tell you that you would need a 894 meter cable. :)

You should read his book The Case for Mars! It is excellent. Here is the link to the new 2011 edition on Amazon. (http://www.amazon.com/Case-Mars-Plan-Settle-Planet/dp/145160811X/ref=sr_1_1?ie=UTF8&qid=1310095840&sr=8-1)

--Brian
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: catiare on 07/08/2011 04:23 am
I read the first edition, it was great. I have to admit I don't remember some of the technical details. I'm waiting for the new version to be available on ebook version so I can read it on my ipad.

In the interview he said a 1-mile tether @ 1 RPM would simulate mars-like gravity and for earth-like gravity you need a 3-Mile @ 1 RPM. I guess by increasing the RPM's you can shorten the length but for some reason he mention several times 1RPM; maybe to avoid motion sickness?

If you download the file, he talks about this on 1:06:17.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: neutrino78x on 07/09/2011 02:33 am
here's the kindle version (http://www.amazon.com/Case-for-Mars-ebook/dp/B004G8QU6U)

Shoudl be able to convert for iPad. :)

He probably meant approximately a mile...it would be like 3300 feet, and a mile is 5280 feet. And I agree with him on 1 RPM; there is some research that most people can adapt to higher RPMs, but why risk it? :)

--Brian
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: docmordrid on 07/09/2011 06:45 am
Why convert the file for iPad/iPhone when Amazon has a free Kindle reader app in the App Store?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Patchouli on 07/09/2011 08:07 am
here's the kindle version (http://www.amazon.com/Case-for-Mars-ebook/dp/B004G8QU6U)

Shoudl be able to convert for iPad. :)

He probably meant approximately a mile...it would be like 3300 feet, and a mile is 5280 feet. And I agree with him on 1 RPM; there is some research that most people can adapt to higher RPMs, but why risk it? :)

--Brian
You know whats funny they have the dead tree version listed from $8 new.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: catiare on 07/09/2011 01:22 pm
here's the kindle version (http://www.amazon.com/Case-for-Mars-ebook/dp/B004G8QU6U)

Shoudl be able to convert for iPad. :)


The Kindle version is the old version, even though is advertised as the new one. Once I got it I realized that and had to request a refund.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: ChefPat on 07/09/2011 02:24 pm
here's the kindle version (http://www.amazon.com/Case-for-Mars-ebook/dp/B004G8QU6U)

Shoudl be able to convert for iPad. :)

He probably meant approximately a mile...it would be like 3300 feet, and a mile is 5280 feet. And I agree with him on 1 RPM; there is some research that most people can adapt to higher RPMs, but why risk it? :)

--Brian
Absolutely amazing. I just looked at that earlier this week & there wasn't a Kindle version.
I think I'll buy it right now. :)
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: qraal on 07/10/2011 09:27 am
If he said that then he's made a major gaffe. The rotation radius for a Mars gravity cable is 338 metres - thus the cable needs to be 676 metres long which is about 2200 feet. Assuming an equal mass on both ends that is.

But the whole RPM thing is a furphy IMO.

I read the first edition, it was great. I have to admit I don't remember some of the technical details. I'm waiting for the new version to be available on ebook version so I can read it on my ipad.

In the interview he said a 1-mile tether @ 1 RPM would simulate mars-like gravity and for earth-like gravity you need a 3-Mile @ 1 RPM. I guess by increasing the RPM's you can shorten the length but for some reason he mention several times 1RPM; maybe to avoid motion sickness?

If you download the file, he talks about this on 1:06:17.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Dave G on 07/10/2011 12:59 pm
If he said that then he's made a major gaffe. The rotation radius for a Mars gravity cable is 338 metres - thus the cable needs to be 676 metres long which is about 2200 feet. Assuming an equal mass on both ends that is.
He could have been wrong.  It was just a quick respose to a listener question, not part of his prepared remarks.

His main point was this: The crew is going to spend 18 months alone on the Mars surface.  They better be in good shape when they get there.  So some gravity on the trip out would be good.

But I suspect a smaller amount of gravity would suffice, perhaps 1/10 Earth gravity.  The crew can excercize with heavier weights to prevent muscle and bone atrophy.  And I suspect everyday activities would be a lot easier at .1g than 0g.  For example, at 1/10 g, things would tend to stay where you put them.  Obviously, we would need to test this in LEO.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: qraal on 07/11/2011 03:14 am
If he said that then he's made a major gaffe. The rotation radius for a Mars gravity cable is 338 metres - thus the cable needs to be 676 metres long which is about 2200 feet. Assuming an equal mass on both ends that is.

But the whole RPM thing is a furphy IMO.

Note I said that the cable length I derived only applies to equal size masses at opposite ends. A lighter counter-weight to the manned vehicle means a larger cable between them for the same RPM and gravity. We can work out the assumed mass-ratios by using that fact.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: qraal on 07/11/2011 03:28 am
If he said that then he's made a major gaffe. The rotation radius for a Mars gravity cable is 338 metres - thus the cable needs to be 676 metres long which is about 2200 feet. Assuming an equal mass on both ends that is.

But the whole RPM thing is a furphy IMO.

Note I said that the cable length I derived only applies to equal size masses at opposite ends. A lighter counter-weight to the manned vehicle means a larger cable between them for the same RPM and gravity. We can work out the assumed mass-ratios by using that fact.

To get a 3 mile cable for 1 RPM and 1 gee means a 20:1 ratio between the masses. Does that seem likely?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Space Junkie on 07/13/2011 02:43 am
You should read his book The Case for Mars! It is excellent. Here is the link to the new 2011 edition on Amazon. (http://www.amazon.com/Case-Mars-Plan-Settle-Planet/dp/145160811X/ref=sr_1_1?ie=UTF8&qid=1310095840&sr=8-1)

I have the 1996 edition. Would it be worth ordering a copy of the new edition too?

The cover of the 2011 edition says it has been "updated and revised to include the latest information about Mars exploration." Has the 'meat' of the book changed much or did he just add an overview of the last 15 years of Mars exploration?

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Dave G on 07/13/2011 07:51 am
You should read his book The Case for Mars! It is excellent. Here is the link to the new 2011 edition on Amazon. (http://www.amazon.com/Case-Mars-Plan-Settle-Planet/dp/145160811X/ref=sr_1_1?ie=UTF8&qid=1310095840&sr=8-1)

I have the 1996 edition. Would it be worth ordering a copy of the new edition too?

The cover of the 2011 edition says it has been "updated and revised to include the latest information about Mars exploration." Has the 'meat' of the book changed much or did he just add an overview of the last 15 years of Mars exploration?



The interview covers this in detail:
http://www.thespaceshow.com/detail.asp?q=1583
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Lobo on 07/13/2011 06:58 pm
If he said that then he's made a major gaffe. The rotation radius for a Mars gravity cable is 338 metres - thus the cable needs to be 676 metres long which is about 2200 feet. Assuming an equal mass on both ends that is.
He could have been wrong.  It was just a quick respose to a listener question, not part of his prepared remarks.

His main point was this: The crew is going to spend 18 months alone on the Mars surface.  They better be in good shape when they get there.  So some gravity on the trip out would be good.

But I suspect a smaller amount of gravity would suffice, perhaps 1/10 Earth gravity.  The crew can excercize with heavier weights to prevent muscle and bone atrophy.  And I suspect everyday activities would be a lot easier at .1g than 0g.  For example, at 1/10 g, things would tend to stay where you put them.  Obviously, we would need to test this in LEO.


This is really the crux of the question, and why an outpost on the moon for long duration stays would be so useful (contrary to those who don't think we should go back to the Moon because we've "already been there".)
We know the effects of long duration 1G (obviously) and we know the effects of zero-G long duration.  What we don't know, and as far as I know, can't really simulate, is the long duration effects of low gravity.
Mars Gravity (1/3 Earth gravity), Moon Gravity (1/6 Earth Gravity), 1/10th Earth gravity, 1/2 Earth Gravity, etc. etc.
It could be that the effects of various less-than-EArth-gravity will scale proportionally.  And that 1/2 Earth Gravity will cause bone and muscle loss, but at half the rate of zero-gravity.  Similar scale for 1/4 or 3/4 Earth Gravity.

But...it could be that there's some minimum threashold gravity that will cause bone and muscle loss to be nominal.  Perhaps 1/3, 1/6, or 1/10 Earth gravity is enough so that muscles and bones have -something- to fight against.  And as long as there's -something-, then the loss is minimal (with perhaps some nominal regiment of physical activity).
The reason to think this may be the case, is due to the regiments in zero-gravity on the ISS, Mir, and Skylab.  Through just a couple hours a day of resistance training, I think they've gotten pretty good at reducing the bone loss, although the muscle loss is still an issue when they return to Earth.  So, if an hour or two is decent to combat it in zero gravity, would several hours of 1/6 gravity each day (normal standing activities) be sufficient to combat it?  Is it only in zero-gravity that we have these real muscle and bone loss issues?  Maybe...  WE only have EArth and zero-G, and nothing inbetween.  And no way to similate something in between.

But a 6-month stay on a lunar outpost would do wonders to study that.
It'd be a great starting point before we go to Mars.  Perhaps we only need an artificial gravity of 1/6 or 1/10 to keep in shape enough to be fit and function on Mars 1/3 gravity.  That would simplify the artificial gravity tech issues greatly.  Maybe some fractional gravity, with the astronauts donning weighted suits to increase their mass to a more useful level of muscle resistence would be a possibility.  But you have to have -some- gravity for that to even be an option.
If for not other reason, that's a reason to go to the moon, and put a big hab there capable of supporting a crew for up to 6 months...if we have any intention of ever leaving LEO again that is.

For later missions to Mars, if we had a VASIMR rocket, as I understand it accelerates the first half of the flight, and then descelerates the 2nd half.  That greates artificial gravity through the whole trip (although I have not idea how much).  So that's a future possibility for artificial gravity...if there's enough acceleration anyway.

On the Moon and Mars, the Astronauts would probably make a fair number of EVA's.  Those unto themselves could be helpful to combat bone and muscle loss because the astronauts would carry so much more mass, that they have much more resistance on their muscles than if they are in the habitat in just clothes.  The Apollo astronauts wore suits that were around 200lbs if I remember correctly.  There might be an argument that Moon and Mars EVA suits shouldn't necessarily be designed to as "light" as possible.  As reliable, durable, and flexible as possible, but the mass of them might actually be of benefit to the astronauts over a long durations stay as a sort of passive "weight training".
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: ArbitraryConstant on 07/13/2011 07:42 pm
For later missions to Mars, if we had a VASIMR rocket, as I understand it accelerates the first half of the flight, and then descelerates the 2nd half.  That greates artificial gravity through the whole trip (although I have not idea how much).
It would be indistinguishable from weightlessness as far as humans were concerned.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: baldusi on 07/13/2011 09:22 pm
This is really the crux of the question, and why an outpost on the moon for long duration stays would be so useful (contrary to those who don't think we should go back to the Moon because we've "already been there".)
We know the effects of long duration 1G (obviously) and we know the effects of zero-G long duration.  What we don't know, and as far as I know, can't really simulate, is the long duration effects of low gravity.
Mars Gravity (1/3 Earth gravity), Moon Gravity (1/6 Earth Gravity), 1/10th Earth gravity, 1/2 Earth Gravity, etc. etc.

You can test that more cheaply and with greater range of Gs in LEO. You've also have the safety of being able to get an astronaut to earth in a few hours. If you design a mobile center arm of enough length, you could test from 1/12G to 2G easily. Don't forget that if higher Gs have a benefit it might work as a treatment for older people.
Now that I think of it, higher Gs could be implemented on Earth easily. That would give you the other side of the curve. Is it a parabola with it's minimum at 1G? Is it a saddle point? Is is sort of lineal? A logit? The half on Earth is testable more cheaply. Why do it? Suppose the 1/3G of Mars provokes bone loss. But it you put 2G on the way back they arrive in perfect health. Or the timing. If you travel at 2G (1.5G or something > 1) they might arrive in better shape than 1G? Quite an interesting question.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: go4mars on 07/13/2011 09:34 pm
My favourite quote from Zubrin's radio interview:

"Cooperation is good up to a point.  That point is when it becomes collusion toward mediocrity." 
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Dave G on 07/14/2011 10:09 am
This is really the crux of the question, and why an outpost on the moon for long duration stays would be so useful ...

I have to say that Zubrin's interview on the Space Show has changed my mind on this. 

Logically, you would want to go to the moon first and test out long duration life support systems, optimize the space suit design, test the effects of reduced gravity, etc.

But Zubrin's point was that logic has little to do with it.  People just aren't excited about going back to the moon.  That means it will never be fully funded, so it's not likely to happen.  By contrast, a manned mission to mars is obviously pushing the boundaries of human exploration, so the general public is much more likely to support it.

But...it could be that there's some minimum threshold gravity that will cause bone and muscle loss to be nominal...
The reason to think this may be the case, is due to the regiments in zero-gravity on the ISS, Mir, and Skylab.  Through just a couple hours a day of resistance training, I think they've gotten pretty good at reducing the bone loss, although the muscle loss is still an issue when they return to Earth.  So, if an hour or two is decent to combat it in zero gravity, would several hours of 1/6 gravity each day (normal standing activities) be sufficient to combat it?

One big advantage of low gravity is that you can use weights.  The problem with rubberized cables is that the resistance increases as you stretch it, so it's difficult to get the resistance right.  With weighs, the resistance is fairly constant.  So for example, in 1/10 gravity, if you ran on a tread mill with a 300 pound weight vest, and a couple of rubber cables to hold you down, that may approximate mars gravity fairly well. 

Also, with just a little gravity, like 1/10 g, things should tend to stay where you put them.  So unlike 0g, you may not need to velcro everything in 1/10 g.

And 1/10 gravity might be enough to keep the human cardio-vascular system working more normally - keeping more blood in the lower body.

Obviously, we'd need to test all of this, but that can be done in LEO.


Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: baldusi on 07/14/2011 11:28 am
One big advantage of low gravity is that you can use weights.  The problem with rubberized cables is that the resistance increases as you stretch it, so it's difficult to get the resistance right.
You just use a cam that compensates the non linearity. I'm still not convinced that linearity is necessary, though.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: go4mars on 07/14/2011 03:24 pm
If you travel at 2G (1.5G or something > 1) they might arrive in better shape than 1G? Quite an interesting question.

Totally agree.  I bet kids who grow up in >1 G would be better weight-lifters/better athletes.  Would probably want to slowly increase though/take a gradual approach. 
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Jason1701 on 07/14/2011 03:35 pm
If you travel at 2G (1.5G or something > 1) they might arrive in better shape than 1G? Quite an interesting question.

Totally agree.  I bet kids who grow up in >1 G would be better weight-lifters/better athletes.  Would probably want to slowly increase though/take a gradual approach. 

Maybe we'll see China taking kids up to orbiting centrifuges to train them as Olympic athletes. ;D
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: DanielW on 07/14/2011 03:48 pm
If you travel at 2G (1.5G or something > 1) they might arrive in better shape than 1G? Quite an interesting question.

Totally agree.  I bet kids who grow up in >1 G would be better weight-lifters/better athletes.  Would probably want to slowly increase though/take a gradual approach. 

Maybe we'll see China taking kids up to orbiting centrifuges to train them as Olympic athletes. ;D

Good grief, Pay me a 100th the cost of that project and I will put them on a parabolic merry-go-round here on earth.

I like faster trips with a tiny fraction of a G due simply to acceleration as opposed to getting fancy with spinning things and the muscle and bone retention programs developed on station will be sufficient for early exploration.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: baldusi on 07/14/2011 04:00 pm
Good grief, Pay me a 100th the cost of that project and I will put them on a parabolic merry-go-round here on earth.
As I already stated, anything over 1G can be researched more cheaply on earth. In fact, I would seriously propose such experimentation.

Quote
I like faster trips with a tiny fraction of a G due simply to acceleration as opposed to getting fancy with spinning things and the muscle and bone retention programs developed on station will be sufficient for early exploration.

If you could find a propulsive technology with enough T/W and isp to give a steady 0.3G all the way to Mars, you'd get something like a three day trip. Solving most problems. With such ISP you could easily reach any place of the solar system and have space habitats. Of course it might take a few centuries to reach that technology.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Lobo on 07/14/2011 09:23 pm
For later missions to Mars, if we had a VASIMR rocket, as I understand it accelerates the first half of the flight, and then descelerates the 2nd half.  That greates artificial gravity through the whole trip (although I have not idea how much).
It would be indistinguishable from weightlessness as far as humans were concerned.

Ok, I wasn't sure how much acceleration people would feel, just that the spacecraft would be under constant acceleration/deceleration the entire trip.  Which is how it can make the Mars trip in 39 days rather than 6 months, and not get to Mars going so fast it can't do a MOI.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Lobo on 07/14/2011 09:55 pm
I have to say that Zubrin's interview on the Space Show has changed my mind on this. 

Logically, you would want to go to the moon first and test out long duration life support systems, optimize the space suit design, test the effects of reduced gravity, etc.

But Zubrin's point was that logic has little to do with it.  People just aren't excited about going back to the moon.  That means it will never be fully funded, so it's not likely to happen.  By contrast, a manned mission to mars is obviously pushing the boundaries of human exploration, so the general public is much more likely to support it.


I'll have to diagree with Zubrin there then, for what it's worth.
People won't be as excited about going back to the Moon as they were about going to the Moon the first time, for various reasons.  But in the same vein, they won't be as excited about going to Mars for the first time as they were about going to the Moon for the first time either.
I think the general public isn't much more excited about goingt o Mars then they are going back to the moon.

Reasons:
1)  The Moon is close, and has captured our imagination since the Dawn of Man.  We didn't even know the orange "wandering star" was a planet for most of human history.  Man dreamed of going to the moon forever, as it seemed so "reachable".
2)  So when we first went to the moon, the world held it's breath and watched.  We were also a FAR less distrated race back then, so something like that had no competition for our attention.  Had we went to Mars during that era, it would also have garnered massive world attention, just not as much as the moon, but far more than going to Mars would garner today.
3)  Although we're a more distracted people today, going back to the Moon will still gather a lot of world attention, precisely because it's still close by, and it still captures the imagination of the masses the way that tiny orange dot can't.  At least at first.  It would probably again seem "routine" and loose front page coverage, as it did during Apollo.
However, if we could establish a base there, and were continually doing more new and interesting things rather than just "flags and footprints" over and over again, I think the world's attention could be held at least at a simmer.
Part of the problem with the ISS, is it took so long to build, and it just goes around in LEO.  Every picture of it looks the same, and other than assembly status, there's been no new attention-getting things going on since the first few construction missions, or the first permanent crew.
I think if we had a HLV that could have thrown up say 4 large modules in the course of a year, and then it's done and in operation, it would have garnered more public attention.  But even then, it would have lost that attention because it'd still just be going around and around in LEO.

But if you put an outpost on the Moon, and give the astronauts roving vehicles and equipment so they can sally forth and go on long duration exploration missions.   Maybe take some teacher or reporter or billionaire up to make the Moon finally once again seem almost within reach of the average person (as so many people thought it was after Apollo 11.  Who didn't think we'd have a moon base and be living on the Moon within a decade back then?).  Methods of in situ resource utilization could be tested (if the materials didn't exist on the moon, like subsurface water-ice, we could still practice using the drills and techniques needed to get to it).
Meanwhile, we have an excellent platform for studying long duration low gravity effects on people (rather than some funky small spinning testbed in LEO), and the effect of such a hostile environment on equipment, EVA suit materials, batteries, etc.  Mars is different than the Moon, but there's a lot of common ground.  Meanwhile, you are only 3 days from home while you test that equipment. 

So in short, I think you can get and hold to some extent the public interest.  There's lots to do and see on the moon.  Not so much on the ISS.  Yea, it won't hold the interest the way Apollo 11 did, because we're far more distracted, and it's not the first time.  But it'll be the first time man has walked on the moon in a large number of American's lifetimes.  Many of us under the age of say 45 don't remember walking on the moon.  We'd like to see that again. 
So I diagree with Zubrin.  And I don't think a trip to Mars will get the same attention that Apollo 11 did, for the reasons I mentioned above.  We only have one close celestial body like that, and we can only go there for the first time once...
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: DaveH62 on 07/15/2011 05:07 pm

I'll have to diagree with Zubrin there then, for what it's worth.
People won't be as excited about going back to the Moon as they were about going to the Moon the first time, for various reasons.  But in the same vein, they won't be as excited about going to Mars for the first time as they were about going to the Moon for the first time either.
I think the general public isn't much more excited about goingt o Mars then they are going back to the moon.


Well done Lobo. I think there is a lot of magic left in going to the moon. It is as if aliens had been to LaGuardia airport and said, "well done, check that planet off our list, these people eat horrible food, rush about, stand in line everywhere and carry all their things with them in black bags on wheels".
We have explored a few acres of the moon. No lava shoots, no drilling into the surface and have not positioned ourselves to use the moon as a source of cheaper fuel for truly longer range missions such as a Mars, or Titan trip. For the price of the ISS we could build a lasting sustainable station on the moon, advance science and build a practical technical foundation for longer term exploration of our solar system. We don't even have the attention span to put a proper rocket development program in place, how could we expect Congress to wait for NASA to build a proper Mars architecture that would meet the safety expectations and cost requirements Congress would place on NASA?
Provide $1 billion in funding to the first American company with a plan to put a permanent base on the moon in by 2020. Have some bonding process (insurance), to guarantee they cover the cost over runs. Make it $5 billion, if you like. It would be a fraction of an internal NASA plan. Let NASA draw up the plan, build out the requirements. Doing that right is tough enough, but hand it off DARPA style, where it can be addressed away from Senator's and Congressman, Presidents and press.
We can get our country back on track, but we have to provide some funding, and take politics (and political oversight) out of the tactical day to day process, and put science, engineering and results front and center.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Geron on 07/16/2011 09:35 am
ISRU is the key reason to go to the moon. It is a perfect place to perfect ISRU technology. If we can get it down on the moon our technology will have a lot of margin for ISRU on Mars. I am suprised that Musk does not see the value in ISRU on the Moon.

Do people think that Musck is more of a Mars direct guy or a Moon IRSU first for propellent production then Mars kind of guy? I'm surprised he does not endorse a plan other than provide rockets at low costs.

If he really wanted to win more funding I think  it would benefit he and his company to come out with a stated plan that the rest of the space program seems to be lacking, why don't the commercial guys come out with their own states architecture for getting to Mars?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Dave G on 07/16/2011 11:21 am
I think there is a lot of magic left in going to the moon.

I agree.

The problem is that we're in the minority on this issue.  So realistically, a moon mission probably won't be fully funded, which means it probably won't happen.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Dave G on 07/16/2011 12:17 pm
Do people think that Musck is more of a Mars direct guy or a Moon IRSU first for propellent production then Mars kind of guy? I'm surprised he does not endorse a plan other than provide rockets at low costs.

If he really wanted to win more funding I think  it would benefit he and his company to come out with a stated plan that the rest of the space program seems to be lacking, why don't the commercial guys come out with their own states architecture for getting to Mars?

The funding for these things comes from the general public.  As any politician knows, when dealing with the general public, it's better to have general goals rather than specific plans.

So I think Musk's current PR is spot on.  He should keep talking about SpaceX's general long term goals, and the specific capabilities of F9, FH, and Dragon, but he should refrain from weighing in on any specific mission plans for BEO.

In addition, Elon has acknowledged that the specialized spacecraft and other payloads required for human missions beyond earth orbit are probably not well suited for commercial companies like SpaceX.  He said that it would be better for NASA to build these "one off" type designs.  So in reality, SpaceX wouldn't be terribly involved with the exact mission plan for going BEO, since that would be driven by these specialized payloads.

By the way, Zubrin's new plan also embraces this concept.  NASA builds the specialized spacecraft, and SpaceX builds the general purpose stuff (FH and Dragon).

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: catiare on 07/17/2011 03:13 am
I think there is a lot of magic left in going to the moon.

I agree.

The problem is that we're in the minority on this issue.  So realistically, a moon mission probably won't be fully funded, which means it probably won't happen.

We can probably do both. If the Mars mission will cost half of a shuttle mission then Nasa could potentially handle a Mars and a Moon mission simultaneously and settle the issue.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Jason1701 on 07/17/2011 03:13 pm
If the Mars mission will cost half of a shuttle mission

I suggest you read the first few pages of this thread. Many reasons have been put forth showing that Zubrin's plan is wildly optimistic on cost and mass.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: catiare on 07/18/2011 07:00 pm
If the Mars mission will cost half of a shuttle mission

I suggest you read the first few pages of this thread. Many reasons have been put forth showing that Zubrin's plan is wildly optimistic on cost and mass.

All these posts are merely hypothetical. Granted I probably know less about rocket science that any of the contributors on this post; I know projects like these have a ton a variables and typically they go over budget. But at this point unless someone does a comprehensive, itemized plan, this is anybody's guess including Mr Zubrin's.

My point is that if the costs of these two programs end up being within NASA's budget because of the Cost savings associated with using SpaceX hardware then is perfectly reasonable to have both projects running concurrently where there will be some cost, technology and know-how sharing. Almost analogous like sending rovers to Mars and a probe to Jupiter on the same timeframe.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Kaputnik on 07/21/2011 07:15 pm
Somehow every Mars thread tends to fall into the same discussion: Moon vs Mars, and artificial gravity vs zero gravity. Plus a few people going on about new propulsion technologies.

Why do we shy away from the real issues- EDLS, surface operations, surface power supply, etc.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: kevin-rf on 07/21/2011 07:18 pm
Somehow every Mars thread tends to fall into the same discussion: Moon vs Mars, and artificial gravity vs zero gravity. Plus a few people going on about new propulsion technologies.

Why do we shy away from the real issues- EDLS, surface operations, surface power supply, etc.

You forgot to include how to keep them from taking our women ;)
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Nathan on 08/06/2011 09:02 pm
I wonder if Chris mckay's red dragon mission modifies dragon much for edl?
From what I can gather all that is required that is different from the crewed dragon is a new parachute. All the articles are very unclear.
Is there anyone on this site who is capable of running and edl simulation on crewed dragon for mars with minimal modification?

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Dave G on 08/07/2011 12:37 pm
Why do we shy away from the real issues- EDLS, surface operations, surface power supply, etc.

And don't forget the big one - mission duration!  6 months to get there, 18 months on the surface, and 6 months to get back - 2.5 years is a very long mission.  Food.  Water.  Hygene.  Space suits.  Backup solutions for all contingencies.

People seem to be treating this as a flags-and-footprints type mission, but because of planetary alignment issues, it ends up being more like a permanent base.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: MATTBLAK on 08/07/2011 12:55 pm
In the 1960s and 70's there were 'sprint' mission designs that had the crews on the Martian surface for only 14-to-21 days before having to leave and go back to Earth - it was all about orbital mechanics and before serious ISRU was ever a gleam in Zubrin's eye. Now, yes; this could definitely be deemed a 'Flags & Footprints' mission. But if it were done ONLY for the first manned mission with a crew of two... Then, next time you'd use the next launch window to only pre-deploy consumables and all the equipment needed for an 18 month stay for a crew of 4. Then, on the launch window after that - nearly four years after the first 'Sprint' mission: send that crew of four to Mars to stay for 18 months.

Apollo 11 only stayed for less than 24 hours on the lunar surface: the later J-Series missions stayed for three days on the Moon. ONE single 14-21 day manned Mars mission would be the Apollo 11 equivalent: a test-flight 'proof of concept'. And, that first 14-to-21 day Mars mission would eclipse ALL those Apollo flights, whilst proving out the technology and hardware, bringing back a lot of rocks and regolith, inspiring pride and paving the way for REAL long-duration Mars missions. So I say: don't sell the 'Flags & Footprint' type mission short. For the price of 3 or 4 Nimitz-class carriers, you could achieve a HELL of a lot of science and operational experience.

And,  Put. Humans. On. MARS. Oh , I know it isn't quite that simple or hand-wavy. But do a couple pathfinder missions first: one to a NEO and then one to Deimos with added Sample Return Probe collection and then you really COULD put humans on Mars by 2030.

But you gotta prove out the Falcon Heavy and Manned Dragon first, then find an extra $2 or $3 billion bucks per year. Elon - working with NASA and with advisors such as Bob Zubrin.... Bob The Mars Builder! Can he fix it (with help)? YES HE CAN!!! :)
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Dave G on 08/07/2011 01:14 pm
In the 1960s and 70's there were 'sprint' mission designs that had the crews on the Martian surface for only 14-to-21 days before having to leave and go back to Earth -

My understanding is that the mission duration for this would be longer than 2.5 years.  In other words, less time on the surface, but MUCH longer getting there and back.  So this would be a bigger challenge than the 2.5 year mission.  The only thing that would change this is some new propulsion technology, yet to be invented. 
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Rocket Science on 08/07/2011 01:16 pm
This concept of a mult-use vehicle is a lot like the Lunar Gemini of the 1960's.

http://www.astronautix.com/articles/bygemoon.htm
http://www.astronautix.com/craft/gemander.htm
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: MATTBLAK on 08/07/2011 01:22 pm
What I should have mentioned is that in order to arrive at Mars to allow a stay of 14-21 days, conventional wisdom used to be a Venus flyby and gravitational assist would be needed - either coming or going - especially for chemical propulsion. I don't know if that is still a requirement if you get enough chemical delta-vee to do a 'fast' 180 day transit to Mars, followed by a hazardous aerocapture. This wouldn't leave you much time - depending on the years' launch windows involved. Some years might give you 14 days at Mars before you had to get going back, other years might give you 19 or more days. A heck of a lot of time spent in transit in Zero-gee. Hard on the crew, I know. A conjunction class mission with Venus flyby would bump the overall duration up to 3 years, instead of 2.5, with little surface stay time for all that duration in transit, to-and-fro.

But like I say: the first mission would be the 'Apollo 8' or 11 equivalent before the real fun began later.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Dave G on 08/07/2011 05:40 pm
But like I say: the first mission would be the 'Apollo 8' or 11 equivalent before the real fun began later.

I'm not following you.  The first mission where? 

A manned mission to Mars takes over 2 years, even if you don't land.  By the time you get there, the planets have gone out of alignment, so you have to wait 2 years for Mars and Earth to re-align in order to get home.

The only way to get the mission under 2 years is to use some new propulsion technology.  Something much faster than any chemical, nuclear, or plasma rocket engine we have today.

So barring some new invention, a manned mission to Mars will last over 2 years.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: MATTBLAK on 08/07/2011 08:02 pm
Er, okay: Apollo 8 orbited the Moon for 20 hours, Apollo 11 landed for 21 hours, Apollo 17 stayed for 75 hours. Between the first lunar mission and the last - a huge leap in stay time. I was merely listing the first manned Mars missions could show a similar progression. In other words, don't throw them in the deep end from the first: baby steps, then the 'big boy pants'.

But I guess, the Apollo analogies would start to be stretched thin from this point on. Just saying, is all.

And I know the first missions would take at least two years. However, depending on the type of mission you take, you can still have a short stay time even if the transits take a long time to and fro. But going from 2 years to 2.5, the stay time gets to be about 18 months while you wait for the planets to re-align.

I know that.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Dave G on 08/08/2011 12:45 pm
Er, okay: Apollo 8 orbited the Moon for 20 hours, Apollo 11 landed for 21 hours, Apollo 17 stayed for 75 hours. Between the first lunar mission and the last - a huge leap in stay time. I was merely listing the first manned Mars missions could show a similar progression. In other words, don't throw them in the deep end from the first: baby steps, then the 'big boy pants'.

But I guess, the Apollo analogies would start to be stretched thin from this point on. Just saying, is all.

And I know the first missions would take at least two years. However, depending on the type of mission you take, you can still have a short stay time even if the transits take a long time to and fro. But going from 2 years to 2.5, the stay time gets to be about 18 months while you wait for the planets to re-align.

I know that.

OK, I think I understand, baby steps are a good.  Gemini & Apollo were all baby steps, with each successive mission doing more.

But with Mars, I don't see the analogy.  If you have to spend over 2 years on the mission, it's probably easier on the crew to spend most of that on the surface.

So for a trip to Mars, I think the baby steps will all be unmanned, and the first manned mission will be full-up - staying on the surface for 18 months.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: MATTBLAK on 08/08/2011 12:56 pm
We've only been talking about 'Baby Steps' because any significant size landing/Ascent craft for crew or cargo might be - best case scenario - a $10 billion dollar project, eating into scarce funds. Maybe Elon could concoct a cheaper, Dragon-based lander for, say $2 or $3 billion. But in these austere times, that still ain't chump change.

A Baby-steps mission might be the before-mentioned manned Deimos/Phobos and Sample-collect combo.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Lobo on 08/08/2011 11:06 pm
Matt,
Yea, I think we see what you are thinking, but Mars is a whole different animal than LEO or the moon.  Both of those you could ease into them.  Put your foot in and check the water.  LEO is always the same distance from the Earth's surface, no matter how long you stay.  Same with the moon.  YOu could land and stay a few hours, a few days, a few weeks, or a few months, and come back whenevery you want for the most part (there are a few orbital mechanics with LOR with the Apollo CSM to take into consideration, but that's only a matter of hours). 

The problem with Mars, is the distance between the EArth and MArs is always changing, we're either getting closer or farther away.  Using current propulsion technologies, and aerocapture technologies, You are looking at 6 months transit time either way.  If you went any faster (which you could, just launch a bigger EDS with bigger tanks on a bigger rocket), you'd get to Mars going so fast, that you couldn't aerocapture, and would bounce off and fly off into deep space.  That would make for a bad day.  So 6 months is about as fast as you can get there without a breakthrough tech like VASIMR (I'll touch on that in a moment).
But barring that, your mission will be about 2 years no matter what, because if you try to come home too soon, you can't catchup to the Earth and will miss it.  So, you can do two 9 month transit times, and a 6 month surface stay, or two 11.5 month transits, with 1 month on the surface, or two 6 month transits with a year on the surface.  Which of those mission profiles seems to make the most sense?
The 6 month transit times because your astronauts can learn far more on the surface then they can floating in space during transit.
So that's why everyone talks about a 2 year mission.  Even if it's the very first and just "flags and footprints" like APollo 11.  The fact is, you just don't have the option to do that and then go home due to orbital mechanics.  You are there for the duration regardless.  Even if you did an Apollo 8 type mission, then you'd have to orbit Mars for a year before you could come home.
There's another type of mission profile with like 1.5 year transit times and 30 days on the surface.  I forget which that is, but the 2 year type mission (a conjunction mission I think?) is the one that everyone goes with because you astronauts are away for about 2 years rather than a little over 3, with a year of that being on the surface, rather than just 30 days.

Now, real quick the reason something like VASIMR changes the game is because it constantly accelerates for the first 1/2 of the trip, then turns around and constantly descelerates the sedond 1/2 of the trip.  So that you arne't going too fast to aerocapture.  In fact, as I understand it, you can get to Mars going pretty much the same speed you were when you broke earth orbit.  So you just ease right into mars orbit without needing heat sheilds and things for aerocapture at Mars.  So (as I understand it) that'd work pretty slick, and simplify a Mars mission since you don't have to make your transit vehicle heat shielded. 
So with VASIMR, since you can keep accelerating, you can get to Mars in about 39 Days!  Actually, you could get there even faster, probably like 15-20 days, but you'd be going so fast you'd either crash at MArs or fly off into space.  The descelerating for the 2nd half of the trip is the key part there.

However, even if you get there in 39 days, your whole mission still has to be 2 years, because the planets would be out of allignment and you'd have to way almost two whole years before you can burn for home.
But, that 39 day is sort of a best case theoretical number, and there'd have to be some major technological breakthroughs in tech to hope to get there.  Probably something like a 3 month transit time would be more realistic.  But it would still be benefitial because you don't have to aerocapture into Mars orbit, so just your landing craft needs to be heat shielded, not your whole transit craft.
But even a 3-month VASIMR is a LONG way off.

So that's why people talk about a 2 year mission, even if it's our first "flags and footprints" mission.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: go4mars on 08/09/2011 01:26 am
  I forget which that is, but the 2 year type mission (a conjunction mission I think?) is the one that everyone goes with because you astronauts are away for about 2 years rather than a little over 3, with a year of that being on the surface, rather than just 30 days.

Hohmann transfer orbit.  Requires the lowest deltaV as well.  Plus while in transit there is potentially more radiation, gravity, and psychology issues than on the surface.  I would plan to send teams for 6 years at a time with overlapping crews.  The first year 1 team shows up, ~2 years later another team joins them, ~2 years later another team joins them, and the next year the first guys ship back home (if they want to or need to).   

Now, real quick the reason something like VASIMR changes the game is
This piece by Bob Zubrin, critical of VASIMR is worth a read I think:
http://www.marssociety.org/home/press/tms-in-the-news/thevasimrhoax
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: baddux on 08/09/2011 01:31 pm
I suppose Mars flyby mission as a precursor would be smarter than a short stay or orbit/moons mission? It would take less than 2 years? I don't see why to practice Mars surface mission with a Mars orbit/moons mission which is in some sense more demanding (more time in empty space, more fuel needed if it's not made on Mars).

I wonder if Spacex could send an unmanned Dragon to fly by Mars and return to earth in the first Falcon Heavy launch? :) (for PR/testing/get some cool video)
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Dave G on 08/09/2011 02:04 pm
I suppose Mars flyby mission as a precursor would be smarter than a short stay or orbit/moons mission? It would take less than 2 years?
No.  Any mission to Mars takes more than 2 years.

Maybe this will help:
http://www.youtube.com/watch?v=-RrpoZPljBo
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Jason1701 on 08/09/2011 02:07 pm
Why is Mars 500 simulating a 520-day mission if it would actually take over two years?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Dave G on 08/09/2011 02:19 pm
... your mission will be about 2 years no matter what, because if you try to come home too soon, you can't catchup to the Earth and will miss it.  So, you can do two 9 month transit times, and a 6 month surface stay, or two 11.5 month transits, with 1 month on the surface, or two 6 month transits with a year on the surface.  Which of those mission profiles seems to make the most sense?
The 6 month transit times because your astronauts can learn far more on the surface then they can floating in space during transit.

Right. 

Actually, it's more like 2.5 years total mission.  The video I posted above shows this fairly well.

Spending more time on the surface is also easier on the crew, both physically and psychologically.

So I think the first manned mission to Mars will be the full-up mission, staying on the surface for 18 months.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: baddux on 08/09/2011 04:09 pm
I suppose Mars flyby mission as a precursor would be smarter than a short stay or orbit/moons mission? It would take less than 2 years?
No.  Any mission to Mars takes more than 2 years.

Ok, I believe you. But here is a Mars flyby plan from the 60's http://www.astronautix.com/craft/jagy1966.htm (http://www.astronautix.com/craft/jagy1966.htm) which says 661 days. I don't know how strong the slingshot effect is so if it can boost the spacecraft to "catch the Earth"?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Robotbeat on 08/09/2011 05:35 pm
I suppose Mars flyby mission as a precursor would be smarter than a short stay or orbit/moons mission? It would take less than 2 years?
No.  Any mission to Mars takes more than 2 years.
...
False. That is only true for Conjunction-class Mars missions with their long surface stays.
http://nssdc.gsfc.nasa.gov/planetary/mars/marsprof.html

Opposition-class Mars missions with their short surface stays are between 400-650 days. Opposition-class missions have greater delta-v requirements than Conjunction-class.

Seriously, if you're going to say something with confidence, have something to back it up with or you'll look foolish. It's not fair to mislead people like that.

I do think that Conjunction-class missions are the way to go, though. That may change as propulsion capabilities advance.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: dmeche on 08/11/2011 07:56 pm
Has Dr. Zubrin ever considered using the VASIMIR plasma engine that Dr. Chang Diaz is developing?  I have read where it can possibly get to Mars in 39 days.  Is this with an initial chemical rocket boost then the VASIMIR kicks in to provide the continuous thrust to Mars?  If the VASIMIR works as projected then would a first mission of 39 days to Mars, 30 days on the surface, and 39 days back be possible?  I am for shorter first stays and then extending the time on the surface after the first initial missions.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Maciej Olesinski on 08/11/2011 09:24 pm
Has Dr. Zubrin ever considered using the VASIMIR plasma engine that Dr. Chang Diaz is developing?  I have read where it can possibly get to Mars in 39 days.  Is this with an initial chemical rocket boost then the VASIMIR kicks in to provide the continuous thrust to Mars?  If the VASIMIR works as projected then would a first mission of 39 days to Mars, 30 days on the surface, and 39 days back be possible?  I am for shorter first stays and then extending the time on the surface after the first initial missions.
Oh yes he did!
http://spacenews.com/commentaries/110711-vasimr-hoax.html
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: A_M_Swallow on 08/11/2011 09:51 pm
Has Dr. Zubrin ever considered using the VASIMIR plasma engine that Dr. Chang Diaz is developing?  I have read where it can possibly get to Mars in 39 days.  Is this with an initial chemical rocket boost then the VASIMIR kicks in to provide the continuous thrust to Mars?  If the VASIMIR works as projected then would a first mission of 39 days to Mars, 30 days on the surface, and 39 days back be possible?  I am for shorter first stays and then extending the time on the surface after the first initial missions.

39 days is grandson of VASIMR - forget it.

The required engine size is enormous and the nuclear power station to produce the electricity is still at the power point stage.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: catiare on 08/11/2011 10:50 pm
What about NTR's? Can an NTR TMI stage be used to shorten a trip to Mars or at least reduce the mass requirement?

I remember Dr. Zubrin mentioned about this in the Case for mars. If I recall correctly that the lack of oxidizer (less mass) and the higher lsp compared to chemical rockets provided some benefits one the mission when using NTR's on a TMI stage.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: FinalFrontier on 08/11/2011 11:14 pm
I suppose Mars flyby mission as a precursor would be smarter than a short stay or orbit/moons mission? It would take less than 2 years?
No.  Any mission to Mars takes more than 2 years.
...
False. That is only true for Conjunction-class Mars missions with their long surface stays.
http://nssdc.gsfc.nasa.gov/planetary/mars/marsprof.html

Opposition-class Mars missions with their short surface stays are between 400-650 days. Opposition-class missions have greater delta-v requirements than Conjunction-class.

Seriously, if you're going to say something with confidence, have something to back it up with or you'll look foolish. It's not fair to mislead people like that.

I do think that Conjunction-class missions are the way to go, though. That may change as propulsion capabilities advance.


And all of this assumes conventional propulsion as opposed to a successful large scale model of something like vasimir.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: baldusi on 08/12/2011 03:08 am
Has Dr. Zubrin ever considered using the VASIMIR plasma engine that Dr. Chang Diaz is developing?  I have read where it can possibly get to Mars in 39 days.  Is this with an initial chemical rocket boost then the VASIMIR kicks in to provide the continuous thrust to Mars?  If the VASIMIR works as projected then would a first mission of 39 days to Mars, 30 days on the surface, and 39 days back be possible?  I am for shorter first stays and then extending the time on the surface after the first initial missions.

39 days is grandson of VASIMR - forget it.

The required engine size is enormous and the nuclear power station to produce the electricity is still at the power point stage.

Is not that difficult to achieve the 20MW VASIMR. Since the lab model is already 200Kw, and they proposed to use 12 engines, so you'd need "only" an order of magnitude more power per engine. Difficult, but doable.
What's beyond current technology is a 2000w/kg electricity generator. Best current solar is 175w/kg. But in Mars it halves. The truth is that there's simply no nuclear reactors. A 10tn nuclear reactor that generates 20MW of electricity seems sort of far fetched, but just because there has been zero development. In any case if we could get 200w/kg solar, you could double your payload from LEO to MLO. The technology is still TRL 5/6, should get to TDL 8, before any of this might happen.

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: go4mars on 08/12/2011 03:38 am
Is not that difficult to achieve the 20MW VASIMR. 

But why not just use Hall thrusters instead?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: douglas100 on 08/12/2011 08:26 am

But why not just use Hall thrusters instead?

They still use electric power. VASIMR has the advantage that it can trade thrust for ISP, but all electrical propulsion is constrained by the power/mass ratio of the electrical source. Baldusi's point is right.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: grr on 08/12/2011 09:59 am
Has Dr. Zubrin ever considered using the VASIMIR plasma engine that Dr. Chang Diaz is developing?  I have read where it can possibly get to Mars in 39 days.  Is this with an initial chemical rocket boost then the VASIMIR kicks in to provide the continuous thrust to Mars?  If the VASIMIR works as projected then would a first mission of 39 days to Mars, 30 days on the surface, and 39 days back be possible?  I am for shorter first stays and then extending the time on the surface after the first initial missions.

39 days is grandson of VASIMR - forget it.

The required engine size is enormous and the nuclear power station to produce the electricity is still at the power point stage.

Is not that difficult to achieve the 20MW VASIMR. Since the lab model is already 200Kw, and they proposed to use 12 engines, so you'd need "only" an order of magnitude more power per engine. Difficult, but doable.
What's beyond current technology is a 2000w/kg electricity generator. Best current solar is 175w/kg. But in Mars it halves. The truth is that there's simply no nuclear reactors. A 10tn nuclear reactor that generates 20MW of electricity seems sort of far fetched, but just because there has been zero development. In any case if we could get 200w/kg solar, you could double your payload from LEO to MLO. The technology is still TRL 5/6, should get to TDL 8, before any of this might happen.

Interestingly, it is not the reactor itself. Heck, put up a shield rather than a containment and let the radiation spew. It would not even pollute. Far more radiation from the sun and background.
It is the fact that current tech with fission is based on thermogeneration which requires the ability to dump that heat. In space, you have to radiate it all, since you do not have matter to dump it to. Those radiators make it heavy.
If we would do some major nuclear fusion work and get electron out DIRECTLY, rather than using steam engines, then we would be in good shape.
Until then, if we want speed, we will need to use NTR.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: ChefPat on 08/12/2011 12:40 pm
IIUC, the VASIMR/Mars Mission Flight Profile requires the VASIMR powered ship to build up speed with a 30 day spiral in Earth orbit, then a 39 day flight to Mars. If that is the case, how is that a 39 day flight & not a 69 day flight?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: baldusi on 08/12/2011 02:05 pm
If Focus Fusion works, it directly gives ions. The interesting question would be if those ions alone aren't a source of thrust.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: kevin-rf on 08/12/2011 02:34 pm
IIUC, the VASIMR/Mars Mission Flight Profile requires the VASIMR powered ship to build up speed with a 30 day spiral in Earth orbit, then a 39 day flight to Mars. If that is the case, how is that a 39 day flight & not a 69 day flight?

Crew transfer at the end of the spiral? Yeah I'm reaching at straws, but that way the crew does not spend 30 days in the Van Allen.

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Kaputnik on 08/14/2011 02:18 pm
Did anybody actually read Zubrin's article about VASIMR? (http://www.marssociety.org/home/press/tms-in-the-news/thevasimrhoax)

I'll say again, propulsion is not the issue. This thread is supposed to be about Mars missions using Falcon. Ergo, it is about multiple cheap launches using conventional technology. SpaceX are not going to develop an advanced propulsion system. What they excel at is refining existing technology and then flying it lots of times. This is the model they have used with the Merlin engine, for example.

SpaceX can participate in Mars missions by developing a cheap launcher (FH) and flying it lots of times per mission. This makes way more sense than pinning hopes on fairytale new propulsion technologies.

So let's bring this discussion back on track. Here are, IMHO, the real issues:
- can SpaceX develop a Mars-lander version of Dragon? What would its payload be?
- Can Dragon or habitats using Dragon-derived systems be made to operate for three years in deep space?
- If we assume that a cryogenic EDS is to be used, what is the trade-off between development costs, performance, and advanced options like reduced boil-off, clustering multiple stages, etc?
- What are the challenges for producing enough electrical power on the the surface, especially for ISRU? Can this be done practicably with PVAs?
- What are the challenges for EVA support on the surface?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Dave G on 08/14/2011 07:11 pm
So let's bring this discussion back on track. Here are, IMHO, the real issues:
- can SpaceX develop a Mars-lander version of Dragon?
They've said the new Dragon LAS will be capable of landing on Mars.  I'm assuming they've run the numbers, or they wouldn't have said that.

What would its payload be?
Not enough for a Mars mission by itself.  You need another module delivered to the surface 2 years ahead of time.

- Can Dragon or habitats using Dragon-derived systems be made to operate for three years in deep space?
Good question.  How would you test this?  I the end, I think the first manned mission to Mars will be high risk.  Remember that high risk missions were once very acceptable.  That attitude will come around again.  It's part of our nature.

- If we assume that a cryogenic EDS is to be used, what is the trade-off between development costs, performance, and advanced options like reduced boil-off, clustering multiple stages, etc?
Huh?  As I understand it, Dragon LAS will use either monomethyl hydrazine / nitrogen tetroxide, or NOFBX.

- What are the challenges for producing enough electrical power on the the surface, especially for ISRU? Can this be done practicably with PVAs?
I believe most mission profiles assume nuclear power.

- What are the challenges for EVA support on the surface?
The suit is biggie.  Today's suits are basically pressurized bags.  Not much mobility, and not very robust for climbing around on sharp rocks.  Plus, you need something that will last for 18 months on the surface.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: JayP on 08/14/2011 07:47 pm
So let's bring this discussion back on track. Here are, IMHO, the real issues:
- can SpaceX develop a Mars-lander version of Dragon?
They've said the new Dragon LAS will be capable of landing on Mars.  I'm assuming they've run the numbers, or they wouldn't have said that.
The history of spaceflight mission proposals is littered with the bones of concepts whose initial numbers looked promising and yet were shown to be unworkable once realityset in. Plus, landing on Mars and launching from the surface back into orbit is a whole different story.
Quote
- If we assume that a cryogenic EDS is to be used, what is the trade-off between development costs, performance, and advanced options like reduced boil-off, clustering multiple stages, etc?
Huh?  As I understand it, Dragon LAS will use either monomethyl hydrazine / nitrogen tetroxide, or NOFBX.
Why do you assume the LAS will be used for TMI? and if so what are they going to use for arrival and landing at the other end?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Kaputnik on 08/14/2011 09:00 pm
They've said the new Dragon LAS will be capable of landing on Mars.  I'm assuming they've run the numbers, or they wouldn't have said that.

I can run a few numbers myself. Dragon has a 10m2 heatshield and a minimum mass of 4500kg, giving a ballistic coefficient of 450kg/m2 which is about five times as 'dense' as any previous Mars entry vehicle. Any payload added to that mass just makes the problem worse.
This means that the Dragon would still be travelling at very high speed when it hits the surface. No existing parachute can survive deployment at these sorts of speeds. Nor has any retro-propulsion system been developed that can fire into a hypersonic airstream like that.

So for Dragon to be able to land any mass on Mars, SpaceX's already multi-purpose LAS must be a truly groundbreaking system which, in addition to its existing dual roles, can perform a never-before-attempted hypersonic retropropulsion role too. Good luck to them in developing it.

Quote
- If we assume that a cryogenic EDS is to be used, what is the trade-off between development costs, performance, and advanced options like reduced boil-off, clustering multiple stages, etc?
Huh?  As I understand it, Dragon LAS will use either monomethyl hydrazine / nitrogen tetroxide, or NOFBX.
You misunderstand me. 'EDS' means 'Earth Departure Stage'. I would guess that a SpaceX based Mars mission will use the much talked of 'Raptor' cryogenic engine/stage for this role. It's possible, though, that MVac would be used, but the IMLEO goes up an awful lot.

Quote
The suit is biggie.  Today's suits are basically pressurized bags.  Not much mobility, and not very robust for climbing around on sharp rocks.  Plus, you need something that will last for 18 months on the surface.
The suit wearing out is certainly an issue. There is also the consumables associated with each EVA. And there could be major issues with dragging Mars dust into the airlock, it is thought that it is highly oxidising and potentially very harmful if inhaled.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: baddux on 08/14/2011 09:17 pm
Has SpaceX published any plans how they would conduct a mars mission? I suppose not.

Anyway I would say the cheapest and still doable way to do a Mars mission with Falcon Heavy + Dragon + Bigelow derived habs is DRM1 style mission . It would require little orbital assembly but only so that you would have to assemble two parts and then off you go, not parallel universe or battlestar galactica :)

In case you are not using Dragon + some tent in its garage as a habitat why would you land on Dragon instead of the hab module? I suppose it would increase the risk if you land the hab first and then land on Dragon and have to land quite near so that you would manage to the hab module.

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Kaputnik on 08/14/2011 09:28 pm
A little orbital assembly is childsplay compared to trying to get a Dragon to land on Mars.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: docmordrid on 08/14/2011 09:47 pm
>
The suit wearing out is certainly an issue. There is also the consumables associated with each EVA. And there could be major issues with dragging Mars dust into the airlock, it is thought that it is highly oxidising and potentially very harmful if inhaled
Back in 2005 this paper was published on lightweight Mechanical Counter Pressure (MCP) suits, speculating on electro-active polymers etc. to change tension on the fly.  Materials science has come a long ways since then to where such a suit should be possible. 

As far as dust goes, taking a twist from the world of surgery might help. There disposable, but thin and very tough, over-garments are used. If such a covering could be made and recycled into new garments locally it might solve the dust problem.

Free form speculation: one idea might be to use a polymer that is water soluble, which would then allow filtering out the unwanted particulates. Spray or dip on a sized form (that could fold flat for storage), let dry, and you have a new cover.

Just a thought....just a thought....
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: go4mars on 08/15/2011 03:31 am
>
The suit wearing out is certainly an issue. There is also the consumables associated with each EVA. And there could be major issues with dragging Mars dust into the airlock, it is thought that it is highly oxidising and potentially very harmful if inhaled
Back in 2005 this paper was published on lightweight Mechanical Counter Pressure (MCP) suits, speculating on electro-active polymers etc. to change tension on the fly.  Materials science has come a long ways since then to where such a suit should be possible. 

As far as dust goes, taking a twist from the world of surgery might help. There disposable, but thin and very tough, over-garments are used. If such a covering could be made and recycled into new garments locally it might solve the dust problem.

Free form speculation: one idea might be to use a polymer that is water soluble, which would then allow filtering out the unwanted particulates. Spray or dip on a sized form (that could fold flat for storage), let dry, and you have a new cover.

Just a thought....just a thought....

I like the idea of painting places like hands with a relatively thin elastomeric sealant, the rest of the body goes in compression band pressure suit, and a big, cheap, easily replaced overcoat full of pockets goes on overtop, like a canvas field geolgists vest, but full length.  Protects the undersuit from tearing, and is tough, repairable, and rugged.  Plus an air-tank back-pack of course.  How to keep the hands warm?  Electric pocket warmers or "heat tape". 
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: kkattula on 08/15/2011 03:49 am
Or, build a water spray (or even full emersion dip) into your airlock to completely clean off any dust, then filter (or flash evaporate & re-condense) the water for next use.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: MATTBLAK on 08/15/2011 04:46 am
That would take a lot of power, though.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: docmordrid on 08/15/2011 04:47 am
You can already buy NiMH or LiION battery heated sox, hunters in very cold northern climates use them all the time. I have 2 pair. If you can make heated sox, you can make heated glove liners.

In the northen Michigan woods in January (subzero °F) and turning them on/off with the belt control I can get 1 - 2 days hunting on a LiION charge.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Kaputnik on 08/15/2011 05:13 am
One of the most promising ways to tackle the dust contamination issue is, apparently, using static-charged 'dusters' that would pick up dust from the suits. A bit like those things you used to use on your TV I suppose.

Re water washing- in the context of this thread (i.e. initial FH based Mars missions) you'd have to assume water would be very strictly rationed. Most architectures require hydrogen to be flown out from Earth rather than gathered locally. This is because, whilst water ice is seemingly abundant on Mars, it will be far harder to gather and process than atmospheric resources which simply need a fan and a filter.

Does anybody here have detailed knowledge of the consumables required for EMUs? I suspect that they may require LiOH cartridges for scrubbing, which may not be reusable. Little things like that could add up to a lot of headaches for a Mars mission.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: docmordrid on 08/15/2011 05:30 am
A 4 Å molecular sieve can remove CO2, H2O, SO2, H2S, and a few other molecules including ethanol. Heat in a vacuum or pressure change can be used to regenerate them.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: MickQ on 08/15/2011 06:45 am
What about using suitports like on the LER, for the first mission or two at least ?  That way the dust cannot be dragged inside.  A light weight cover over the port could protect against dust being blown in whilst the suit is "off port ".

Mick.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: kkattula on 08/15/2011 07:30 am
What about using suitports like on the LER, for the first mission or two at least ?  That way the dust cannot be dragged inside.  A light weight cover over the port could protect against dust being blown in whilst the suit is "off port ".

Mick.

You'd need a cover over the hab port and also the port on the back of the suit while in use.

Somehow, I never liked those.  Say you needed to do a suit repair or servicing. You'd have to bring it inside anyway.  What if the either port won't seal? You've lost an EVA suit.

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: kkattula on 08/15/2011 07:42 am
That would take a lot of power, though.

Not that much, and only for brief periods each day.

The amount of water is more daunting, but you probably want a fair amount around the Hab for radiation shielding.


How about hitting the suit with blasts of dry N2 while the crew member touches a small Van de Graaff generator?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Kaputnik on 08/15/2011 08:58 am
That would take a lot of power, though.

Not that much, and only for brief periods each day.

The amount of water is more daunting, but you probably want a fair amount around the Hab for radiation shielding.


How about hitting the suit with blasts of dry N2 while the crew member touches a small Van de Graaff generator?

I doubt they would be using water for radiation shielding. If we are still talking about a FH-launched mission using Dragon-esque landers, landed payload is going to be less than 5t per craft, which is going to make every gram count.

Much more sensible to pile up regolith around the habitats after arrival.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: RanulfC on 08/15/2011 06:28 pm
In the 1960s and 70's there were 'sprint' mission designs that had the crews on the Martian surface for only 14-to-21 days before having to leave and go back to Earth - it was all about orbital mechanics and before serious ISRU was ever a gleam in Zubrin's eye. Now, yes; this could definitely be deemed a 'Flags & Footprints' mission. But if it were done ONLY for the first manned mission with a crew of two... Then, next time you'd use the next launch window to only pre-deploy consumables and all the equipment needed for an 18 month stay for a crew of 4. Then, on the launch window after that - nearly four years after the first 'Sprint' mission: send that crew of four to Mars to stay for 18 months.
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19880014327_1988014327.pdf (http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19880014327_1988014327.pdf)

General FYI; "Sprint" class mission here where a "supply" cargo vehicle is sent ahead of the astronauts to Mars using a conjunction-class (Homann) minimum energy trajectory. The manned vehicle uses a faster trajectory with a @ one-way trip time of 234 days. A surface stay of 30 days and a return trip time of @116 days. Total mission time for the manned crew is 380-days or 1-year, 15 days.

This is called the "Split-Sprint" mission concept, and uses on-orbit assembly, on-orbit propellant transfer both in Earth and in Mars orbit, and pre-positioned supplies. It also uses two re-usable chemical "boost" tugs for EDS, and aero-capture at both ends of the journey.

Note that the "groundrules" for the study assume a lot including a 200,000lbs to-LEO HLV as a baseline and single "stack" assembly at a space station, and no ISRU at all. Not mentioned but seems to be assumed is LBO-technology for the propellants since the cargo-vehicle waits in Mars orbit almost 18 months for the manned mission to arrive with the stored MDS propellants of Liquid Hydrogen and Oxygen.

Can such a mission be "done" with the Falcon-9 (@117,000lb, or 53,000kg to LEO) Heavy? I don't see why not, that's 14 launches for each "cargo" flight about 16 for the manned mission assuming that the F9H has to "carry" the entire mission payload on its own. And also assuming that the "no-ISRU" and delivery of the return propellant all sent from Earth.

Then there's the http://www.moonminer.com/Multi-Planet-Voyages.html (http://www.moonminer.com/Multi-Planet-Voyages.html) "Two-for-One" special... Drop by Venus for 3-weeks and Mars for two-months and still get back to Earth in a little over 2-years total trip time :)

Randy
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Kaputnik on 08/15/2011 07:32 pm
The 1988 Neihoff mission is non ISRU.
If you choose a non-ISRU mission plan, then you are trading that development for the need for a massively enhanced EDLS capability. Personally I think ISRU is better 'bang for buck'.

Getting more mass to LEO is not the answer to all your problems, no matter how cheaply you might be able to do it.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: RanulfC on 08/15/2011 08:47 pm
The 1988 Neihoff mission is non ISRU.
If you choose a non-ISRU mission plan, then you are trading that development for the need for a massively enhanced EDLS capability. Personally I think ISRU is better 'bang for buck'.
I'd noted that the mission baseline was non-ISRU, and I agree that ISRU is a better option. However, how do you get the propellant up to the EDS from the surface? If you're doing a standard "Mars-Direct" mission (per subject) then it's not a worry, however you're limited on your surface mass since everything has to fit into a "single-shot" architecture.

Mars EDL mass has always been "problematical" due to the thin Martian atmosphere and usually ends up being propulsive for any decent sized down-mass. The limits of your "landed-mass" with a direct-from-the-surface-EDS end up constraining your entire Mars-departure leg, usually restricting the return to a lower-energy trajectory and hence the usually long trip times.

No orbital "infrastructure" at Mars and you're either bringing the propellant with you or (again) having to have some way of automatically moving the ISRU propellant from the surface to orbit prior to Mars Departure.
Quote
Getting more mass to LEO is not the answer to all your problems, no matter how cheaply you might be able to do it.
Well as I pointed out IF you have "mass" (as in infrastructure) on-Earth-orbit you have some advantages over the "standard" direct-launch architecture. It may not answer ALL your "problems" but it actually can help reduce many of them by not constraining your architecture.

Randy
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Dave G on 08/16/2011 02:33 am
You misunderstand me. 'EDS' means 'Earth Departure Stage'.
Right, sorry.  I read it fast and thought EDL.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Dave G on 08/16/2011 02:43 am
Has SpaceX published any plans how they would conduct a mars mission? I suppose not.

SpaceX has wisely stayed away from this, at least publicly.  They advertise some capabilities, but never any specific mission profiles.  SpaceX's customer would develop the mission profile, and there would be other non-SpaceX hardware involved as well.

Bottom line: SpaceX can't get to Mars by themselves, but they could make it economically feasible for NASA to go to Mars, and that's a big deal.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: A_M_Swallow on 08/17/2011 03:25 am
Has Dr. Zubrin ever considered using the VASIMIR plasma engine that Dr. Chang Diaz is developing?  I have read where it can possibly get to Mars in 39 days.  Is this with an initial chemical rocket boost then the VASIMIR kicks in to provide the continuous thrust to Mars?  If the VASIMIR works as projected then would a first mission of 39 days to Mars, 30 days on the surface, and 39 days back be possible?  I am for shorter first stays and then extending the time on the surface after the first initial missions.

39 days is grandson of VASIMR - forget it.

The required engine size is enormous and the nuclear power station to produce the electricity is still at the power point stage.

Is not that difficult to achieve the 20MW VASIMR. Since the lab model is already 200Kw, and they proposed to use 12 engines, so you'd need "only" an order of magnitude more power per engine. Difficult, but doable.
What's beyond current technology is a 2000w/kg electricity generator. Best current solar is 175w/kg. But in Mars it halves. The truth is that there's simply no nuclear reactors. A 10tn nuclear reactor that generates 20MW of electricity seems sort of far fetched, but just because there has been zero development. In any case if we could get 200w/kg solar, you could double your payload from LEO to MLO. The technology is still TRL 5/6, should get to TDL 8, before any of this might happen.



A 12 MW spacecraft can get to Mars in about 4 months.
A 200 MW spacecraft is needed for a 39 day trip.

I am predicting, on cost grounds, that they will stick at 12 MW.

http://www.adastrarocket.com/aarc/ToMars (http://www.adastrarocket.com/aarc/ToMars)

edit: add url
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: A_M_Swallow on 08/17/2011 03:34 am
The 1988 Neihoff mission is non ISRU.
If you choose a non-ISRU mission plan, then you are trading that development for the need for a massively enhanced EDLS capability. Personally I think ISRU is better 'bang for buck'.
I'd noted that the mission baseline was non-ISRU, and I agree that ISRU is a better option. However, how do you get the propellant up to the EDS from the surface? If you're doing a standard "Mars-Direct" mission (per subject) then it's not a worry, however you're limited on your surface mass since everything has to fit into a "single-shot" architecture.

{snip}
Do not bother to take the propellant up to the EDS/(Mars Transfer Vehicle) from Mars, just bring it from Earth - particularly if using electric propulsion.

The ISRU can be used to make fuel for the Mars ascent stage.  The ascent stage has a far bigger delta-V and could use CO + O2.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Kaputnik on 08/17/2011 11:06 am
In the context of a FH-enabled Mars architecture, there is one over-riding constraint:
PLF diameter.

Basing numbers of current state of the art and heritage achieved performance, you get the following:
3.6m PLF-> 750kg at entry, 250kg payload
5m PLF-> 1500kg at entry, 500kg payload
6.5m PLF-> 2500kg at entry, 830kg payload

You could view those numbers as conservative, but they reflect the experience of all succesful Mars landings to date. If we push the numbers right out to the absolute limit of current technology, utilising capsule lift and a low altitude landing site, things obviously improve. For example:
3.6m PLF-> 2000kg at entry
5m PLF-> 3900kg at entry
6.5m PLF-> 6400kg at entry

It is too hard to say how these masses would translate into payload, bearing in mind the above must include the heatshield, backshell, parachutes, landing gear, and retros.

To get above these numbers, you need a bigger PLF, or some sort of new hypersonic decelleration technique. New hypersonic technology is going to be very expensive to develop, I would posit that it is out of SpaceX's league.

So, for a low-cost SpaceX-enabled mission, we are stuck with the paltry masses indicated above. This makes ISRU and surface-rendezvous essential. I think it also makes it unfeasible to be launching the TEI propellant from Mars.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Joris on 08/17/2011 01:31 pm
A 12 MW spacecraft can get to Mars in about 4 months.
A 200 MW spacecraft is needed for a 39 day trip.

Well, that all depends on the weight of the spacecraft, doesn't it?





Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Biolawyer on 05/17/2013 03:02 am
My problem is the throw-away nature of each module.  We need to think in terms of CAPABILITIES.  Zubrin is ONLY thinking in terms of Total Recall ("get your a$$ to Mars").

How about this instead: 

1.  Detach the Russian Orbital Segment for all the life support and living space and docking ports and backup propulsion, along with one of the robot arms on ISS.
2.  Falcon Heavy puts a 120,000 pound propulsion module with a small nuclear reactor that has BOTH nuclear thermal rocket engines and Ion electric engines.  I can hear the doubters now but you are wrong.  NERVA built and tested a nuclear thermal rocket in the 1960's.  The idea is simple and it has been shown to work:  Superheat the exhaust as it passes the nuclear pile.  Ion thrusters currently power several VERY small space ships but they can be scaled up easily so long as there is electrical power.  Nuclear reactors have powered ships for 80 years and space nuclear reactors were designed in the 1950's.  We can do this, really.   
3.  A few Soyuz or Dragon spacewalks would be needed to assemble the structure, attach supporting rods and hook up the electricity.  Why is avoiding spacewalks such a big deal?  We have been doing it for 50 years.  We just did an ISS space walk with almost no prep or warning.  No big deal.
4.  All the ships that service ISS could dock with the new station, resupply it, deliver crew, top off the fuel tanks, and deliver the nuclear material for the reactor.

Now any country can decide to build a lander, berth it with the "International Space Ship" and we can go anywhere in the solar system.  Anywhere!  We can build a permanent Moon base, visit Mars, the Asteroid Belt, wherever, although we probably could not establish a colony on Mars unless we had 2 or 3 International Space Ships we would get a LOT further than Zubrin's vision.

The next mission to Mars should be landing another Rover like Curiosity BUT instead of an explorer the new rover should be designed to retrieve cargo from other rocket launches with a mission to basically set up camp, arrange the solar arrays, unpack and test the oxygen and methane generating equipment and so on.

CAPABILITIES NOT DESTINATIONS.  If we build it, THEN we can go.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: QuantumG on 05/17/2013 03:08 am
Welcome to the forum.. that's some nice necrothreading.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: solartear on 05/17/2013 06:59 am
Welcome to the forum.

1.  Detach the Russian Orbital Segment for all the life support and living space and docking ports and backup propulsion, along with one of the robot arms on ISS.

Pretty sure the Russian Orbital Segment, and rest of ISS, is not designed for use outside of Earth's friendly magnetic field, so electronics would get fried from a coronal mass ejection, never mind the humans. Perhaps Bigelow could make a sheath for some segments and fill with water, but then it's more expensive and still might leave some parts exposed. Skylab 2 seeks to address the difficulties involved.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: KelvinZero on 05/17/2013 11:11 am
Welcome to the forum.

1.  Detach the Russian Orbital Segment for all the life support and living space and docking ports and backup propulsion, along with one of the robot arms on ISS.

Pretty sure the Russian Orbital Segment, and rest of ISS, is not designed for use outside of Earth's friendly magnetic field, so electronics would get fried from a coronal mass ejection, never mind the humans.

Heard the same, pity. However Biolawyer might be interested in Nautilus-X
http://en.wikipedia.org/wiki/Nautilus-X
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: ChefPat on 05/17/2013 03:14 pm
Nuclear reactors have powered ships for 80 years
Welcome to the Forum.
What ship was sailing with a Nuke in 1933? ;)
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Patchouli on 05/17/2013 03:34 pm
A 12 MW spacecraft can get to Mars in about 4 months.
A 200 MW spacecraft is needed for a 39 day trip.

Well, that all depends on the weight of the spacecraft, doesn't it?


That's where it get's interesting the faster the trip the smaller and lighter the rest of the spacecraft can be.

For a 39 day trip the Mars transfer vehicle habitat section could be as small as  a Russian Mir core type station module.

Though for safety I'd size everything to have as much as 180 days of life support in case there's a failure.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: GalacticIntruder on 05/17/2013 07:34 pm
Mr Zubrin is a fan of nuclear propulsion, but he has gone out of his way to squash Chang's VASIMR pet project. He considers it a waste of resources and a scam. I agree with him. I would not use such a device, or nuclear anything, to rationalize a Mars mission on this particular thread.

http://www.youtube.com/watch?v=myYs4DCCZts (http://www.youtube.com/watch?v=myYs4DCCZts)

Zubrin also hates overly complicated missions, and scifi technology, that impedes the immediate attempt to land humans on Mars. His idea, three FH's is kind of the minimum would need to get to Mars. Cargo first on low energy trajectory, then a high energy trajectory with the crew.

http://news.yahoo.com/robert-zubrin-latest-mars-mission-using-spacexs-falcon-191600364.html (http://news.yahoo.com/robert-zubrin-latest-mars-mission-using-spacexs-falcon-191600364.html)

http://www.marssociety.org/home/press/announcements/wallstreetjournalpublisheszubrinplantousespacexhardwaretosendhumanstomarsthisdecade (http://www.marssociety.org/home/press/announcements/wallstreetjournalpublisheszubrinplantousespacexhardwaretosendhumanstomarsthisdecade)

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Lars_J on 05/17/2013 08:09 pm
Mr Zubrin is a fan of nuclear propulsion, but he has gone out of his way to squash Chang's VASIMR pet project. He considers it a waste of resources and a scam. I agree with him. I would not use such a device to rationalize a Mars mission on this thread.

http://www.youtube.com/watch?v=myYs4DCCZts (http://www.youtube.com/watch?v=myYs4DCCZts)

Zubrin also hates overly complicated missions, and scifi technology, that impedes the immediate attempt to land humans on Mars.

Holy cow, I guess I must have managed to avoid hearing Zubrin speak in public before this, but what an insufferable twit he comes across as. Ugh.  With that kind of personality he wouldn't be able to get any support for anything, even *if* his ideas were agreed upon by all.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: meekGee on 05/17/2013 08:13 pm
Mr Zubrin is... 

It's Dr. Zubrin. He didn't spend six years in Zubrin Medical School to be called "mister," thank you very much.

And Lars_J, yeah, I know what you mean.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: spectre9 on 05/17/2013 09:58 pm
Zubrin is crazy.

Crazy and brilliant are not mutually exclusive.

The man in a genius and I love listening to him speak.

I don't agree with everything he says but he always encourages the discussion of all challenges related to getting to Mars and many other more Earthly related concerns that would be off topic for this forum.

If you haven't watched this please do so it will explain to you where Mars Direct came from.

http://www.youtube.com/watch?v=uDWvsdEYSqg

This is a more detailed explanation. Be warned he recycles jokes.  :P

http://www.youtube.com/watch?v=Mm34Muv6Lsg
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: GalacticIntruder on 05/17/2013 10:59 pm
I would not call Dr Zurbin crazy. He is just very focused and passionate on his goal to have humans, preferably Americans, on Mars ASAP. He also comes across as very annoyed, that it did not happen decades ago. We still do not have a realistic plan, WITH MONEY, to go today, or anytime before 2035. Goals are one thing, real hardware and 10-20 billion dollars is another.   

He does not like anyone who offers anything that he thinks will prevent a human mission. If it cost too much and is too complicated, or does not exists, or just plane risk averse, like NASA is, it is a DOA for him. There are plenty of excuses not to go, we hear them every time someone says humans to Mars. We don't have a 150mT rocket, so he thinks a few FH could do. That is what this thread is for.

We don't know what Elon's HTM plans are, but if it requires the public sector, aka NASA, I doubt it will happen.  So it seems we are back to square one. The private sector now wants to go, but does not have the money, and the public sector does not want to go, but has the money.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Lar on 05/17/2013 11:44 pm

We don't know what Elon's HTM plans are, but if it requires the public sector, aka NASA, I doubt it will happen.  So it seems we are back to square one. The private sector now wants to go, but does not have the money, and the public sector does not want to go, but has the money.
Maybe the private sector will raise the money. Stranger things have happened. It has to MAKE money in the end though. Somehow.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: QuantumG on 05/17/2013 11:52 pm
Maybe the private sector will raise the money. Stranger things have happened. It has to MAKE money in the end though. Somehow.

You know the private sector includes many many things that don't "make money", right?

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Lar on 05/18/2013 12:23 am
Maybe the private sector will raise the money. Stranger things have happened. It has to MAKE money in the end though. Somehow.

You know the private sector includes many many things that don't "make money", right?

Yes, but there aren't too many foundations with the budget needed.

At least not yet. Maybe if Page and Brin sign up for the Giving Pledge and then give all their money to a foundation that wants to jumpstart exploitation/colonization ?

Edit: if that's not what you meant, please elaborate...
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: QuantumG on 05/18/2013 12:38 am
Yes, but there aren't too many foundations with the budget needed.

At least not yet. Maybe if Page and Brin sign up for the Giving Pledge and then give all their money to a foundation that wants to jumpstart exploitation/colonization ?

Edit: if that's not what you meant, please elaborate...

It doesn't have to be a charity, but yes.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: spectre9 on 05/18/2013 02:19 am
Private dollars could easily put flags and footprints on Mars.

It's only a select few dot com billionaires that even care about space.

The trick is getting things cheap enough for those select few to be able to fund it.

A Falcon Heavy Mars Direct style plan is the best near term solution to this problem.

Zubrin just needs to prove that all the hardware can fit on Falcon Heavy and he hasn't done that yet.

Inspiration Mars has taken a step towards proving that you can fly by Mars using Falcon Heavy using advanced ECLSS. Getting there is difficult but actually landing is much harder.

The atmosphere of Mars makes it easy to slow down but nobody wants to demonstrate aerocapture even at Earth.

There are technology gaps and advanced propulsion isn't one of them that needs to be filled although it would be nice.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: a_langwich on 05/19/2013 03:48 am
Mr Zubrin is... 

It's Dr. Zubrin. He didn't spend six years in Zubrin Medical School to be called "mister," thank you very much.

And Lars_J, yeah, I know what you mean.

Which is why XCOR's Doug Jones wryly asked, if Elon Musk and Jeff Greason wanted to retire on Mars, how they would feel about living there in a group of about 20 people, one of whom was Zubrin.  :)   Now that is funny!

His engineering numbers are usually reasonable, but like some other engineers, he feels his expertise extends to every other field of human knowledge.  The Dunning-Kruger Effect sets in.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Avron on 05/19/2013 01:33 pm
Before i get all excited in terms of reactors on mars.. I need to see just how the reactor is to be cooled..
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: kkattula on 05/19/2013 02:53 pm
Maybe the private sector will raise the money. Stranger things have happened. It has to MAKE money in the end though. Somehow.

No, it just has to convince potential investors it could make money in the end. ;)
 
Plenty of big projects get investment yet fail to ever realize their predicted returns. Some are later bought out for cents on the dollar, and operated at profit and/or benefit to humanity.
 
How could it make money? Off the top of my head, I can think of three revenue streams:

1) Entertainment.  Discovery channel type reality TV of training, final crew selection, mission, etc. Could probably bring in tens if not hundreds of millions per year. The first landing and Mars walk could be worth billions.

2) Science data.  NASA and other institutions would probably pay hundreds of millions for the missions data, to include their own instruments, and to have experiments performed.

3) Merchandising.  All sorts of authorised memorabilia plus space craft and Mars base toys. Tie it into a kid's TV show and it could again be worth hundreds of millions, maybe more.

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Lar on 05/19/2013 03:12 pm
Maybe the private sector will raise the money. Stranger things have happened. It has to MAKE money in the end though. Somehow.

No, it just has to convince potential investors it could make money in the end. ;)
 
Plenty of big projects get investment yet fail to ever realize their predicted returns. Some are later bought out for cents on the dollar, and operated at profit and/or benefit to humanity.


I was insufficiently precise and I'm going to claim :) that's what I meant. But ya. [1]

I think at least one satellite operating company went bankrupt, assets got bought, and the new owner is making money ( can't remember who)

Sadly, another one splashed all their birds, no?

But I don't think that commercial ventures that start out as for profit but fail were what QG meant. I invite him to elaborate because I'm terrible at guessing.

1 - what I should have said was "have a plan that seems plausible to investors that makes money"...
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: QuantumG on 05/19/2013 11:53 pm
But I don't think that commercial ventures that start out as for profit but fail were what QG meant. I invite him to elaborate because I'm terrible at guessing.

I merely meant an organization with a goal other than making money. There's millions of them that are not run by the government.

Random (completely unrelated) example: The Royal Automobile Club of Victoria (http://en.wikipedia.org/wiki/Royal_Automobile_Club_of_Victoria) has an annual budget of $443.3M and 2,623 staff. They don't make a dime and have no government subsidies.

Something with less members, making a bigger contributions, could pay for a whole lot of crew training, hardware development, launches, etc, etc. Combine with a for-profit sister company to reap media rights, data selling, patent licensing, etc, for added funding.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Lar on 05/20/2013 12:33 am
But I don't think that commercial ventures that start out as for profit but fail were what QG meant. I invite him to elaborate because I'm terrible at guessing.

I merely meant an organization with a goal other than making money. There's millions of them that are not run by the government.

Random (completely unrelated) example: The Royal Automobile Club of Victoria (http://en.wikipedia.org/wiki/Royal_Automobile_Club_of_Victoria) has an annual budget of $443.3M and 2,623 staff. They don't make a dime and have no government subsidies.

Something with less members, making a bigger contributions, could pay for a whole lot of crew training, hardware development, launches, etc, etc. Combine with a for-profit sister company to reap media rights, data selling, patent licensing, etc, for added funding.


It would be neat if the National Geographic Society, or some such, sponsored something, ya... Thanks for clarifying.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Biolawyer on 05/22/2013 09:52 pm
Quote
Flight 1. Falcon Heavy puts Earth Return Vehicle into Mars orbit.
Flight 2. Falcon Heavy puts Mars Ascent Vehicle on Mars surface.
Flight 3. Falcon Heavy sends Crew Transfer Vehicle to Mars to precise landing.
Crew spends 500 days on the surface, uses the MAV to ascend to the ERV and return to an ocean landing.

BTT: 

1.  Can Falcon Heavy put the ERV on Mars surface (where, for example, Raptor powered methane engines can be refueled) instead of doing the Mars orbital rendezvous (without all the ground tracking stations)? 

2.  Regarding the 3rd flight, why not a Falcon 9/Dragon with rendezvous in Earth orbit?  Why does Dr. Zubrin reject a Mars Transfer vehicle?


Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: go4mars on 07/13/2015 07:24 am
 
2.  Regarding the 3rd flight, why not a Falcon 9/Dragon with rendezvous in Earth orbit?  Why does Dr. Zubrin reject a Mars Transfer vehicle?
Can you elaborate on these?
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: maitri982 on 03/06/2016 01:17 am
If a raptor upper stage is made and is made to work with the Falcon Heavy, then perhaps a more straightforward Mars Direct does indeed become possible.

I don't want to wait for MCT to have people on Mars...this is one way it could happen sooner.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: guckyfan on 03/06/2016 07:12 am
If a raptor upper stage is made and is made to work with the Falcon Heavy, then perhaps a more straightforward Mars Direct does indeed become possible.

I don't want to wait for MCT to have people on Mars...this is one way it could happen sooner.

Who should build that architecture?

SpaceX is already stretching it to the limits designing one system, the MCT. They may land a reusable methane stage on Mars as a precursor mission but not develop it into a fully manned architecture. Also I see 2030 as  really fast. Why an interim manned system? Just to win that 2025 bet? I don't think Elon Musk works that way.

He could pull a Mars One. Send a handful of people on a one way mission with Dragon and resupply them with methane upper stages until MCT is working. But that is very high risk and Elon Musk has already stated he won't send people until return fuel production is achieved. It also does not come cheap.
Edit: Actually cheap but not cheap enough that Elon Musk could do it as a sidetrack to developing Raptor.

NASA doing it? If free to use their present budget for it they may be able. But post Apollo NASA and fast don't seem to mix any more.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: maitri982 on 03/06/2016 02:23 pm
I agree that Musk probably would not do this on his own.  So if it was to happen it would be a NASA mission...in other words will never happen since NASA claims Orion and SLS are for manned Mars, which is made up Fantasy of course. 

Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: spacenut on 03/06/2016 04:39 pm
If Musk can get the BFR built, then NASA and other's may get involved.  Even the FH with a methane upper stage might get people interested in doing something. 
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: envy887 on 04/28/2016 08:36 pm
If Musk can get the BFR built, then NASA and other's may get involved.  Even the FH with a methane upper stage might get people interested in doing something.

BFR could in theory throw so much mass that a relatively straightforward exploration type mission wouldn't need major new operational abilities, just bigger versions of existing or mostly-developed hardware.

A 15 million lbf thrust BFR (which Musk has mentioned) with a mostly custom stack on top could throw a 6-person crew to Mars and back in one Apollo style shot, no ISRU or orbital refueling needed. The hardware riding on that BFR could be mostly BEAM, Dragon and Raptor derived: a triple Raptor LEO stage and single Raptor TMI stage; all propulsion past TMI done by SuperDraco (LMO insertion, Mars EDL, Mars ascent and rendezvous, TEI, Earth EDL).
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: philw1776 on 04/29/2016 04:52 pm

BFR could in theory throw so much mass that a relatively straightforward exploration type mission wouldn't need major new operational abilities, just bigger versions of existing or mostly-developed hardware.

A 15 million lbf thrust BFR (which Musk has mentioned) with a mostly custom stack on top could throw a 6-person crew to Mars and back in one Apollo style shot, no ISRU or orbital refueling needed. The hardware riding on that BFR could be mostly BEAM, Dragon and Raptor derived: a triple Raptor LEO stage and single Raptor TMI stage; all propulsion past TMI done by SuperDraco (LMO insertion, Mars EDL, Mars ascent and rendezvous, TEI, Earth EDL).

Not quite.
A 15 million pound thrust BFR might possibly throw a 6 person crew to Mars' surface even without orbital refueling assuming Mars aerobraking to bleed off most of the velocity but ISRU would ABSOLUTELY be needed to get back to Earth.

SuperDracos have lousy ISP and would be a terrible design for the many Km/sec needed for Mars ascent & rendezvous, TEI, etc.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: envy887 on 04/30/2016 09:51 pm
True enough. Storable methalox would probably be necessary for inserting the transit hab into LMO, and for TEI. A dedicated vacuum-optimized booster would be needed to get the return Dragon close to LMO. SuperDracos would only do EDL and maybe the last bit of dV to LMO.

My point is that if Musk gets BFR built, missions to Mars on this scale are nearly a certainty, and missions of a much bigger scale are likely... regardless of NASA's interest.
Title: Re: Zubrin's Falcon Heavy Mars Mission
Post by: Elmar Moelzer on 05/01/2016 03:41 am
Before i get all excited in terms of reactors on mars.. I need to see just how the reactor is to be cooled..
I would presume that you use the ground as a conductor to conduct the heat away and otherwise just have a long tube of sorts to pump the cooling water through. Should be easier than cooling nuclear reactors in space and we do know how to do that.