Author Topic: Zubrin's Falcon Heavy Mars Mission  (Read 213990 times)

Offline pathfinder_01

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Re: Zubrin's Falcon Heavy Mars Mission
« Reply #20 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.).
« Last Edit: 05/14/2011 10:38 am by pathfinder_01 »

Offline QuantumG

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Re: Zubrin's Falcon Heavy Mars Mission
« Reply #21 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.

Human spaceflight is basically just LARPing now.

Offline MATTBLAK

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Re: Zubrin's Falcon Heavy Mars Mission
« Reply #22 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.
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Offline pathfinder_01

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Re: Zubrin's Falcon Heavy Mars Mission
« Reply #23 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.


Offline QuantumG

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Re: Zubrin's Falcon Heavy Mars Mission
« Reply #24 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.
Human spaceflight is basically just LARPing now.

Offline QuantumG

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Re: Zubrin's Falcon Heavy Mars Mission
« Reply #25 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.
Human spaceflight is basically just LARPing now.

Offline pathfinder_01

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Re: Zubrin's Falcon Heavy Mars Mission
« Reply #26 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.
« Last Edit: 05/14/2011 11:00 am by pathfinder_01 »

Offline MATTBLAK

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Re: Zubrin's Falcon Heavy Mars Mission
« Reply #27 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.
« Last Edit: 05/14/2011 11:05 am by MATTBLAK »
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Offline QuantumG

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Re: Zubrin's Falcon Heavy Mars Mission
« Reply #28 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.

Human spaceflight is basically just LARPing now.

Offline pathfinder_01

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Re: Zubrin's Falcon Heavy Mars Mission
« Reply #29 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.
« Last Edit: 05/14/2011 11:26 am by pathfinder_01 »

Offline QuantumG

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Re: Zubrin's Falcon Heavy Mars Mission
« Reply #30 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.
Human spaceflight is basically just LARPing now.

Offline MATTBLAK

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Re: Zubrin's Falcon Heavy Mars Mission
« Reply #31 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.
« Last Edit: 05/18/2011 10:51 am by MATTBLAK »
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Offline QuantumG

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Re: Zubrin's Falcon Heavy Mars Mission
« Reply #32 on: 05/14/2011 11:53 am »
Great Matt, if you want to consider that do so.. but use numbers.

Human spaceflight is basically just LARPing now.

Offline MATTBLAK

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Re: Zubrin's Falcon Heavy Mars Mission
« Reply #33 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.... ;)
« Last Edit: 05/14/2011 09:54 pm by MATTBLAK »
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Offline Downix

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Re: Zubrin's Falcon Heavy Mars Mission
« Reply #34 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
chuck - Toilet paper has no real value? Try living with 5 other adults for 6 months in a can with no toilet paper. Man oh man. Toilet paper would be worth it's weight in gold!

Offline Robotbeat

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Re: Zubrin's Falcon Heavy Mars Mission
« Reply #35 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!
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Offline Downix

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Re: Zubrin's Falcon Heavy Mars Mission
« Reply #36 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.
« Last Edit: 05/14/2011 07:37 pm by Downix »
chuck - Toilet paper has no real value? Try living with 5 other adults for 6 months in a can with no toilet paper. Man oh man. Toilet paper would be worth it's weight in gold!

Offline alexw

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Re: Zubrin's Falcon Heavy Mars Mission
« Reply #37 on: 05/14/2011 07:48 pm »
What's a "W/h" intended to mean?

Offline Downix

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Re: Zubrin's Falcon Heavy Mars Mission
« Reply #38 on: 05/14/2011 08:03 pm »
What's a "W/h" intended to mean?
Watt/hour.  Basic electricity term to determine power demand.
chuck - Toilet paper has no real value? Try living with 5 other adults for 6 months in a can with no toilet paper. Man oh man. Toilet paper would be worth it's weight in gold!

Offline telomerase99

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Re: Zubrin's Falcon Heavy Mars Mission
« Reply #39 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!

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