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?
To answer the question you meant to ask.. yes, kero is space storable.
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 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.
Edit: Also, Nautilus-X is a joke. :D
just plan with what we have and get going. Thats the sentiment anyway.
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!"
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.
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.
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.
Zurbin is too optimistic about cost and mass and safety.
Zurbin is too optimistic about cost and mass and safety.
He's not optimistic about safety, he's blasé about safety.
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.
Unless I'm missing a major plot-point or piece if information.
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.
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.
Great Matt, if you want to consider that do so.. but use numbers.
Try 19 mT per habitation module, 21 mT for the solar array, 11 mT for the engines... then add fuel, 40 mT of itGreat 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.... ;)
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.
What's a "W/h" intended to mean?Watt/hour. Basic electricity term to determine power demand.
"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.
What's a "W/h" intended to mean?Watt/hour. Basic electricity term to determine power demand.
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.
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.
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
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.)
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.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.
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.
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."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.What's a "W/h" intended to mean?Watt/hour. Basic electricity term to determine power demand.
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?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.
{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.
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.
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.
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?
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.
"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"
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.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.
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.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.
As I put it as 8500 Watts per hour, I can only assume there is some ulterior motivation at work here.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.
Have you ever built an electric circuit before?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.
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.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.
Just what kind of solar cells are we talking about here?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.
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.
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.
As I put it as 8500 Watts per hour, I can only assume there is some ulterior motivation at work here.
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.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.
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?QuoteAs 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.
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.
Proof to me to not reply before my first cup of coffee. I meant Watt-hours. Stubborn me for not waiting.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
Friends;Fully understandable
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:That is one way to do it, of course. And for cheap-direct, it's a good one.
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.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.
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.
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.
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.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.
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.
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.
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.
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
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?
... 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. ...
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
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.
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
"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
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 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.
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.
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.
What timeclock are we racing against, that a mission has to be done within this decade? How about 2025?
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.
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.
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.
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?
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.QuoteIf 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.
...if you want more than just a flags/footprints mission with two astronauts and a Dragon on Mars.
Could a James Cameron type of person fund or lead a moon mission and pay for it as an HBO series?
Could a James Cameron type of person fund or lead a moon mission and pay for it as an HBO series?
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!!!
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.
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.
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.
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.
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.
RZ SSP
Initial Deceleration (m/s^2) 42 10.64
Time (s) 25 112.7
distance (km) 140 616.6
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.
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.QuoteIf 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.
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.
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.
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.
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.
Translation - advanced propulsion is pork and is to be avoided.
By that claim, we've never constructed anything in LEO. I have a $100 billion investment which tells me that claim is bogus.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).
LEO construction is not pork, nor a long pole.
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.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.
It is, and it also shows how the Mars Direct concept has been eclipsed by new capability.
Falcon and Dragon?QuoteWhen 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.
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.It is, and it also shows how the Mars Direct concept has been eclipsed by new capability.
Falcon and Dragon?QuoteWhen 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.
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?
Advanced propulsion is not pork.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.
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?
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.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.
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
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: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.
- 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.Agreed. All of these are critical.
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
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?
"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..
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.
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.
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 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.
"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..
"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/).
Um, we already have data:"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:"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
http://en.wikipedia.org/wiki/Mars_Radiation_Environment_Experiment
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.
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.
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.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..
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.
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 ...
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.
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.Landing in Hellas Impact Basin! :)
I presume that the dragons heat shield can take this?
Any particular coordinates? I would go for the east coast near the valley networks. Though the colles would be interesting to chech out.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.Landing in Hellas Impact Basin! :)
I presume that the dragons heat shield can take this?
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
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 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'.
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
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.Landing in Hellas Impact Basin! :)
I presume that the dragons heat shield can take this?
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.
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?
What is certain is current EDL methods are apparently inadequate.
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20100017668_2010017622.pdf
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
It seems to me that one most expensive aspects of manned mars is the return vehicle from mars surface.
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.
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
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.
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
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.
...if viable...
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.
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
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.
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.
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?)
...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
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.
Searched: Advanced Supersonic Parachutes for Mars
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.
...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.
I was wondering what the highest velocity a supersonic parachute could deploy, so it seems somewhere around mach 2.2....
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 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.
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?
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.
No reason Dragon couldn't start propulsive landing while still supersonic.
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.
and if not, could Dragon be feasibly modified with a larger parachute compartment to accomodate the Mars chutes?
I have no doubt that Dragon would need considerable modifications in any case. Parachute compartment size is probably the least of your problems.
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).
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?
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 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.
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.
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.
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.
Quote from: neutrino78xI 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?
Quote from: neutrino78xI 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.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:
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?
Exploration is usually funded by governments. Colonization follows exploration, and is often privately funded, but not always.
Quote from: neutrino78xI 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.
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?
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.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 :)
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.
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.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 :)
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'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
Standard is 5.2 meters, but the FH page also says "Custom fairings are available at incremental cost."
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,
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 [...]
But in EFFECT it means that no "claims" to outer-space territory can be valid since no "government" can legally back those claims,
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.
::::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.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.QuoteNote 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.
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.You keep asserting that but it's not true.
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.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.
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.
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.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?
Quote from: neutrino78xAnd 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.
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?
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.
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.
X2Spoilsports :P
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.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...
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.
X2Spoilsports :P
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
Quote from: LoboX2Spoilsports :PQuote from: douglas100I'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.QuoteIt 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.
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...
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.
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.
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.
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.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.
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.
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.".
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.
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.
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?
here's the kindle version (http://www.amazon.com/Case-for-Mars-ebook/dp/B004G8QU6U)You know whats funny they have the dead tree version listed from $8 new.
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
here's the kindle version (http://www.amazon.com/Case-for-Mars-ebook/dp/B004G8QU6U)
Shoudl be able to convert for iPad. :)
here's the kindle version (http://www.amazon.com/Case-for-Mars-ebook/dp/B004G8QU6U)Absolutely amazing. I just looked at that earlier this week & there wasn't a Kindle version.
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
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.
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.
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.
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.
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)
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?
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.
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.
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.
This is really the crux of the question, and why an outpost on the moon for long duration stays would be so useful ...
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.You just use a cam that compensates the non linearity. I'm still not convinced that linearity is necessary, though.
If you travel at 2G (1.5G or something > 1) they might arrive in better shape than 1G? Quite an interesting question.
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.
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.As I already stated, anything over 1G can be researched more cheaply on earth. In fact, I would seriously propose such experimentation.
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.
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.
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.
I think there is a lot of magic left in going to 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?
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.
If the Mars mission will cost half of a shuttle mission
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.
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.
Why do we shy away from the real issues- EDLS, surface operations, surface power supply, etc.
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 -
But like I say: the first mission would be the 'Apollo 8' or 11 equivalent before the real fun began later.
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.
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 isThis piece by Bob Zubrin, critical of VASIMR is worth a read I think:
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.
... 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.
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.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.
...
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!
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.
False. That is only true for Conjunction-class Mars missions with their long surface stays.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.
...
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.
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.
But why not just use Hall thrusters instead?
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.
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?
So let's bring this discussion back on track. Here are, IMHO, the real issues: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.
- can SpaceX develop a Mars-lander version of Dragon?
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.
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.So let's bring this discussion back on track. Here are, IMHO, the real issues: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.
- can SpaceX develop a Mars-lander version of Dragon?
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?- 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.
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.
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.- 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.
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.
>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.
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.
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
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....
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.
That would take a lot of power, though.
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?
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)
The 1988 Neihoff mission is non ISRU.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.
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.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.
You misunderstand me. 'EDS' means 'Earth Departure Stage'.Right, sorry. I read it fast and thought EDL.
Has SpaceX published any plans how they would conduct a mars mission? I suppose not.
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.
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 1988 Neihoff mission is non ISRU.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.
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'.
{snip}
A 12 MW spacecraft can get to Mars in about 4 months.
A 200 MW spacecraft is needed for a 39 day trip.
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.
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.
Nuclear reactors have powered ships for 80 yearsWelcome to the Forum.
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?
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.
Mr Zubrin is...
Maybe the private sector will raise the money. Stranger things have happened. It has to MAKE money in the end though. Somehow.
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.
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...
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.
Maybe the private sector will raise the money. Stranger things have happened. It has to MAKE money in the end though. Somehow.
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.
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.
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.
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.
Can you elaborate on these?
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?
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.
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).
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.