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Why do people consider the Mars Direct Hab & ERV too small.
IIRC, for a four man crew, its 250 square feet per crewman overall in the Hab.
In the ERV its about 125 square feet per crewman (and on the ERV, you are returning to Earth so you get the morale advantage of more real time communications the longer you are into the return).
Why do people think thats too cramped for whats only a six month mission? I believe a number of Salyut cosmonauts stayed stayed in similiar conditions for six months. And they weren't making history while doing it.
If you go to Mars with what you have as I suggested, you can go to Congress (and the American people) with a solid achievement that builds your case for an expansion of future Mars missions.
Zubrin was absolutely right about the fact that you can't go more than 10 years from when the program is approved to actual landing.
You can't continue to go to Congress and the American people with nothing but cool pictures about what you hope to build on Mars "some day" and hope to continue to obtain funding.
You've got to make history or at least have flight capable hardware well underway as soon as humanly possible.
Are you seriously suggesting that a geologist and biochemist spending 500 days on Mars assisted by two engineers and advised by the best scientists on Earth can't do one heck of alot of exploration and good science?!?!?! For that matter they could also explore thousands of square miles.
The FIRST mission isn't supposed to explore EVERYTHING.
Sure, we could always send more scientists. More equipment. Explore a larger area.
But part of any initial mission is just to prove we can get there and back safetly. That the basic equipment works.
Shannon Lucid walked off the shuttle after six months in the cramped confines of Mir. She did that coming into a ONE G gravity field.
Why should be think that Mars bound astronauts setting foot into a ONE THIRD G field after six months in the HAB would have any problems? And if that issue, rotating the HAB and upper stage via tether to produce one third G is hardly a show stopper.
What GCN is advocating is a very "Von Brauning" idea of space exploration.
That we build all the hardware to do it "right" and that the act of building the hardware will show just how committed we are.
Thats backwards.
Its like building a military force and then deciding what kind of war we want to fight.
Makes alot more sense to decide what war you plan on fighting and THEN build the military thats capable of it.
We want to get to Mars. Lets build what we can ASAP and just go. If the long term political will dies after two or three missions............then at least we've gotten two or three of the most productive manned space missions in human history.
My short term goal is to see that first manned mission to Mars and back.
My long term goal is to string a bunch of short term goals together in sequence.
The first voyage to Mars will be the greatest of all expeditions, once begun (not that it hasn't but most people quite rightly won't believe it until they see it) it will consume world attention. Scientists, engineers, teachers and students and yes even the public will follow every step, it's in our bloodstreams. Naturally, politicians will position themselves, those for and against; the media will be positive as it will be the greatest show off earth. This voyage has been discussed for years and years, it will be done right technically. The experience of Apollo was not all negative, it taught what not to do, and as GCN keeps saying this MUST be done right, if it becomes a pure political flag planting event then it's over for a long long time.
So what is right? Creating an affordable transportation system between Earth and Mars is the key, initially it must be used wisely for the obvious: exploration and science. Then as soon as possible, it must move towards becoming self financing. This can't be expected to happen in a short time unless a miracle occurs, but steady progress towards reducing the costs through ISRU and other technologies must be the objective. And then we go beyond.
Overall not likely.
there is approximately ZERO chance of Mars Expeditions becoming self financing.
You forget the obvious GCN.
We will never go to Mars with manned missions for science or to learn, or as Dr. Robert Zubrin says to set up a new human civilization.
Those have never been enough motivation for such endeavours as we are speaking of.
We'll go to Mars for dick waving, flag waving, jingolistic political reasons.
Might as well get used to that.
We'll probably send the first starships our for the same reasons in a 100 years or so.
The bulk of the scientific work on Mars does't have to be done onsite.
Collecting samples and making measurements for more than a year will provide enough work of scientists back on Earth for decades. And a couple of scientists on Mars with little to but sampling and research for more than a year are more than capable of doing that.
My understanding of GCNs overall objections to "3 Ares V, Mars Semi-Direct" is that a single Ares V launched from Earth can't deliver large enough of a Hab module to the surface of Mars.
What about a "four Ares V rocket" Mars Semi-Direct Mission?
Four man crew of course.
One Ares V launches the Mars Ascent Vehicle.
One Ares V launches the Earth Return Vehicle to Martian orbit.
One Ares V launches a Hab module to Earth Orbit
One Ares V launches a chemically propelled Earth Departure Stage to Earth Orbit which docks with the Hab. It then propels the Hab to Mars.
That would seem a reasonable compromise.
Anyone who can do charts or graphics that could make up something that I could print out to go with my lobbying campaign that reflects this?
I think your ideas for the initial landing are good GCN.
The remainder I would characterize as gold plating and I would not bother with it until we have full approval for the initial manned missions.
After all this GCN I still have one question.
Is the Semi-Direct 6 man mission doable with the 130 ton capacity (about 280,000 lbs. to LEO ) Ares-5 in only three launches assuming chemical engines only?
If it is not. Can it be done in three Ares-5 launches with a a five man crew or a five man crew.
Yeah, six launches per manned mission still unnerves me.
Huh? No, not even a four man crew is possible with a 130MT rocket assuming a HAB arranged like MarsDirect in only three launches. Even three is pushing it. The ERV would then be a good size, and that would provide enough for the MAV, but the HAB is still not good enough.
Not by a long shot if you intend to bring anything beyond "poking and pictures" science. Especially not if you intend to build anything with the measly cargo limit in a reasonable number of pieces.
Don't think of it as six launches per mission, think of it as six per mission to set up the base and find where the water is, with "regular" missions requiring only two launches once we have a fuel supply and an upgraded MAV. Same number of flights as MarsDirect, just 50-100% more crew and far more capability.
Now I think I understand GCN.
Is it your idea that the first couple of manned expeditions deliver REUSABLE Mars Ascent Vehicles which will be used to return astronauts to the Earth Return Vehicles on subsequent missions?
I can see that making sense. As I assume that a reusable MAV could also be used for long distance site to site transport of astronauts to areas on Mars well away from the landing sites.
So, can six launches, three putting up the HAB, Mars Ascent Vehicle, and Earth Return Vehicle and three putting up chemically propelled Earth Departure Stages work with a planned six man crew? Using Ares V?
After all this GCN I still have one question.
Is the Semi-Direct 6 man mission doable with the 130 ton capacity (about 280,000 lbs. to LEO ) Ares-5 in only three launches assuming chemical engines only?
If it is not. Can it be done in three Ares-5 launches with a a five man crew or a five man crew.
Yeah, six launches per manned mission still unnerves me.
ended[/i] and look where we ended up?
Apollo ended for political reasons.
No changes in the Apollo mission architecture could change that.
What you are trying to do GCN (while commendable) is to ensure changes in political and national will by mission planning and architecture.
That doesn't work.
We could spend 500 billion dollars on a huge, flashy Manned Mars program, with all the equipment reusable for followup missions, ...........and the President and Congress could still cancel the program after the first Mars landing. (probably after the second or third, but they could still cancel it).
But would it be doable?
You put one professional geologist and an amateur biologist on the surface of Mars for a year and I bet they could do one heck of alot of work.
The samples and first hand measurements alone they could make would be priceless.
I'm not going there. We either go to Mars with a crew big enough, or we shouldn't go at all. Six is the best compromise between rockets of practical size plus how much more you can accomplish with a dozen boots on the ground.
Three men to Mars is too much like repeating Apollo, and repeating Apollo on Mars would be MUCH WORSE than never going in the first place!
We go big enough to get stuff done, or we don't go.
At this point, I don't really care if it is recreating Apollo.
Give me three manned landings on Mars a year in duration each.
THEN I'll worry about whether we need to go back every two years indefinitely.
I tried to post this earlier.
How much would it reduce the mission mass to reduce the crew size from 6 astronauts to 3?
Lets not go there. Even a four-man crew is awfully small to bother with given all this trouble and expense to get to Mars. Six with the option for eight substituting the laboratory space, thats the ticket.
But would it be doable?
You put one professional geologist and an amateur biologist on the surface of Mars for a year and I bet they could do one heck of alot of work.
The samples and first hand measurements alone they could make would be priceless.
By the way, isn't zero G transfer of liguid hydrogen an operation loaded with complications?
AFAIK it's unproven, but potentially extremely helpful.
I prefer to not gamble on unproven methods.
Lets keep things as simple as possible
By the way, isn't zero G transfer of liguid hydrogen an operation loaded with complications?
I tried to post this earlier.
How much would it reduce the mission mass to reduce the crew size from 6 astronauts to 3?
How would it effect mission mass requirements if you reduced the crews to only three astronauts?
You are probably right about that. I had not considered the costs on the ground that have to be paid whether we launch one a year or six.
But I was asking about the route you would go for the large booster kind of as an intellectual exercise.
IIRC, in one of the Case For Mars studies, there was a look at some 100 meter tall superboosters. One I believe used four SRBs around an "Ares type" core.
I thought it was in that range of lift capacity.
How would development costs change for something that used four SRBs (the extended ones probably) as part of the first stage. would very heavy modification of the ground facilities be necessary?
Great post GCN!!
You pretty well answered my questions. Your point about the Mercury astronauts was rather insightfull.
Regarding Mars Semi-Direct, do you think that Zubrins concept of a 100 meter tether from the Hab to the spent upper stage and using rotation around the center of gravity to be a viable means of simulating Mars level gravity on the outbound leg of a Mars mission?
And finally, IF we had to have a larger booster sometime in the future than the Ares V, in what direction would you suggest going? Say something in the 150-200 ton payload to LEO size range?
So how many launches per "Mars Semi-Direct" mission would you suggest GCN?
You think I have an inordinate fear of dockings? Not the dockings themselves but the multiple launches just to pull off one manned mission.
Just a single failed launch could torpedo your enter mission.
Same with a more Mars Direct type mission of course, but to me, fewer launches means lower overall mission risk.
Every time Hans and Franz have to trundle to the pad to me means a heightened risk at all levels of something going wrong.
And IIRC, the Mercury astronauts were told that a 10% chance of dying was a reasonable guess. If it was good for them why not good for us on a far more daring mission?
And what exactly kind of rocket did you suggest GCN up above as a bridge between chemical rockets and nuclear thermal systems of the future?
I don't recall ever hearing of it.
Your basic idea seems reasonable GCN.
By I'm opposed to the multiple dockings for each mission.
If just one docking out of several fails for whatever reason, your mission is screwed.
And I think we need to decide what would be an acceptable level of risk for a first mission.
I think a 10% chance of death of one or more astronauts is reasonable. It is what the Mercury astronauts were supposed to accept. Its reasonable for a mission of this scope.
And about a 25% chance of mission failure.
That is, the astronauts survive, but for whatever reasons, the majority of the first mission objectives are not met (Mars landing aborted or severely shortened, loss of all or most of the samples and scientific data, mission success in other areas but loss of large amounts of hardware expected to be reused.......)
If absolutely necessary, I could go with the "Mars Semi-Direct" option.
That is, Hab & Mars Ascent Vehicle are sent to the Martian surface while the Earth Return Vehicle with the fuel and supplies (and more room of course) is parked in Martian orbit.
The Mars Ascent Vehicle only has to make enough fuel to ascend to orbit.
But nothing more complicated than that.
No Earth orbital Assembly. No multiple dockings in Earth orbit or Mars orbit (aside from the one between the Mars Ascent Vehicle and ERV).
No 8 man crews with two surgeons and a complete operating suite. No nuclear thermal rocket engines on early missions.
What I'm hearing from many amounts to "gold plating". The attitude that if we're going to spend 50 billion dollars then lets load it down with every bell and whistle possible.
Thats the same attitude that turns U.S. military procurement into decades long, budget busting nightmares.
And I'm annoyed at the attitude that astronauts safety and comfort have to somehow be near guaranteed.
If we needed 24 astronauts for the first three manned Mars missions (3 four man primary crews, 3 backup crews) I would wager good money that we could get literally hundreds if not thousands of volunteers who could meet the skills and physical requirements.
If they willing to risk it, then why can't we on the ground?
We "risked more" than the Soviets?
Doing what?
Going into LEO. Just like the four Soviet cosmonauts did.
And the Apollo program had plenty of expansion possibilities.
It was used as the Skylab program. And many in NASA regret the loss of Skylab today because as some said, it was a large station with lots of potential for reuse and expansion.
Plus, modified Skylab station could've easily been used as the mission module for a manned Mars mission (it would have to remain in orbit of course).
You don't land the Habs in Mars Direct next to each other.
You land them within 500 miles of each other so you are within driving range of the pressurize rovers.
You get steady expansion of outposts across the Martian surface as well as the redundancy of multiple life support facilities.
Finally, the Saturn V was compatible with a nuclear upper stage. By any measure, the Apollo program had a wide range of possibilities.
res-V.
And NO, its stupid to spend $50,000,000,000+ and a dozen years on a Mars architecture that doesn't have any hope for a real upgrade! Thats ridiculous, if you had to start completely over to significantly improve performance. No no, rushing to Mars with no thought about what to do after we get there, in a desperate frenzy to get our boots red, its a sure-fire way to make Mars the new Apollo... great publicity for a while, then axed when it has no future. MarsDirect particularly does not have any options for much of an upgrade, its already using the biggest practical launch vehicle, aerobraking, hair-thin margins, and the best practical fuels. There is no where for it to go! And so... we won't go anymore.
I disagree.
You can't design a system that is ready for all contingencies and you can't design a system that the U.S. govt. can't abandon if it so chooses.
The Mars Direct Program is upgradable.
Zubrin designed it specifically to be adaptable to use future Nuclear Thermal Rocket engines (something you should applaud) GCN that would allow it to put 50% more payload on the Mars Surface in future missions.
And in any case, Zubrins program is for the steady buildup of assets on the Martian surface, specifically, Hab modules and pressurized rovers. The more assets you have on the Martian surface, the greater your margin of safety and the more assets available for base building.
Finally, I like the Soviet methodology of spaceflight. Sure, they never got to the moon. But their spaceflight methods only cost the lives of FOUR cosmonauts as opposed to FOURTEEN American astronauts in space and set every space endurance record worth mentioning.
And what is fundamentally unworkable about 6 months back to Earth in an ascender cab?
Is it really THAT much different than spending a year in Salyut 6?
Mars Direct is the hardest of all. The ascent vehicle has to lift the crew plus all their supplies for a 6 month trip plus their Mars Transit Vehicle plus their Earth reentry vehicle, and put the whole package on a trajectory back to Earth.
The absolute minimum would be 3 crew and a Soyuz class capsule, that will weigh 7 mT. Add the supplies including plenty of happy pills for the six month journey
Whats the big deal about the crew spending 6 months on the way back to Earth in a relatively small Ascender cab?
The Soviet Salyut crews spent twice that amount of time in a smaller area.
Sure, they were in Earth orbit, but Mars explorers would be returning from one of the greatest adventures in human history and communications with Earth would be growing steadily more rapid after more than a year of longer delays on Mars.
There is no reason to believe that three or four astronauts can't make a safe, healthy, sane return in a relatively small capsule for just six months or so.