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Dayton Kitchens

Member

From: Norphlet, Arkansas

Registered: 2005-12-13

Posts: 183

Re: Whats does NASAs Manned Mars Architecture Look Like Now?

I know the return to the moon architecture is the CEV and lunar landing being launched separately, docking in orbit, then going to the moon.

But I don't recall what the last version of the manned Mars mission architecture looks like?

Last I heard it was basically Mars Semi-Direct with six launches.

Three launches orbiting the Earth Return Vehicle, Mars Ascent Vehicle, and the Mars Hab that functions as the mission module on the outbound trip and on Mars surface.

These three vehicles are supposed to dock with three nuclear powered upper stage launched separately into Earth orbit.

I can't remember that ever being updated.

What is the latest?

GCNRevenger

Member

From: Earth

Registered: 2003-10-14

Posts: 6,056

Re: Whats does NASAs Manned Mars Architecture Look Like Now?

Last I heard, NASA was just going to start thinking about it in earnest next year

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[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

cIclops

Member

Registered: 2005-06-16

Posts: 3,230

Re: Whats does NASAs Manned Mars Architecture Look Like Now?

Yep, Scott Horowitz said NASA would revisit the Mars Design Reference Mission and begin work on the Mars Architecture next year. The planned Orion, Ares I and V elements have been designed to support the Mars mission as well as the Moon. However, two pieces are missing, the Mars Transit Vehicle (MTV) and the lander. The lander is tricky, right now no one seems to know how to land heavy payloads on Mars. Airbags won't scale, a new parachute/Skycrane concept has been invented for MSL but that only delivers 775 kg. Human missions will need much more than that.

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[color=darkred]Let's go to Mars and far beyond -  triple NASA's budget ![/color] [url=irc://freenode#space]  #space channel !! [/url] [url=http://www.youtube.com/user/c1cl0ps]   - videos !!![/url]

Dayton Kitchens

Member

From: Norphlet, Arkansas

Registered: 2005-12-13

Posts: 183

Re: Whats does NASAs Manned Mars Architecture Look Like Now?

Is NASA likely to stick with the six man mission rather than the four man that Dr. Robert Zubrin originally envisioned?

RedStreak

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From: Illinois

Registered: 2006-05-12

Posts: 541

Re: Whats does NASAs Manned Mars Architecture Look Like Now?

Out of everything Zubrin suggested my bet is they'll modify Semi-Direct since the ERV could be based on the CEV, whether modified or not it essentially fits the bill.

I would like to see a HAB used as the manned lander but all this is just wishful thinking on my part.

SpaceNut

Administrator

From: New Hampshire

Registered: 2004-07-22

Posts: 29,428

Re: Whats does NASAs Manned Mars Architecture Look Like Now?

Ok lets see if a 1.5 lunar Architecture is adaptable, in so much as the plan now includes international base construction which is different than a LSAM to do sortie missions I would say it is possible to use what we are developing for mars.

What is a Mars Transit Vehicle? I think this is close to a well shielded ISS module, plus the Orion, multiple stretched EDS brought up by changing the CALV for orbital assembly. If one EDS unit is used to push us towards mars with the second to to make it posible to enter orbit before allowing that stage to enter mars atmoshphere much in the same way as the Kistler units propose.
This may make for reusuability for return of a much larger cargo return from mars.

The Mars lander is a bit more tricky in that we do not know if we need to design it to be a Habitat cargo unit or just cargo only or a combination that allows for it to be reusuable with insitu resources.

We most likely can use the PICA shield for the lander, sterable parachute and or some sort of disposable glider wings after entry.

Dayton Kitchens

Member

From: Norphlet, Arkansas

Registered: 2005-12-13

Posts: 183

Re: Whats does NASAs Manned Mars Architecture Look Like Now?

I still think that the basic Mars Direct is the way to go.

Four man crew.   Direct Earth to Mars flight.  Direct Mars to Earth return.

Even if to get  the necessary mass means you have to build a 150 ton to LEO capacity booster (not that hard to do) and cut the safety margins razor thin.

I think manned spaceflight could use some danger and excitement anyway.

GCNRevenger

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From: Earth

Registered: 2003-10-14

Posts: 6,056

Re: Whats does NASAs Manned Mars Architecture Look Like Now?

150MT is so that hard, the Ares-V hits 130MT and its the biggest practical rocket to build without serious new infrastructure and having to start from scratch. And razor thin margins are a plan for disaster! What happens if the mission winds up absolutely needing 160MT? You can't make MarsDirect any smaller!

But even then, suppose it does work, MarsDirect will never be good for anything except direct flights with small payloads or crews and no option for growth or upgrades. I also think that the baseline MarsDirect is a bad deal as far as what science you get for the amount of trouble.

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[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

cIclops

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Registered: 2005-06-16

Posts: 3,230

Re: Whats does NASAs Manned Mars Architecture Look Like Now?

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 and some air, water and food and it will be at least 10 mT. All that has to be landed first together with an ISRU unit, the engine, tanks and structure. A single Ares V won't be able to deliver much more than about 5mT in one package to the surface, so this will have to be broken into separate pieces and reassembled on Mars.

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[color=darkred]Let's go to Mars and far beyond -  triple NASA's budget ![/color] [url=irc://freenode#space]  #space channel !! [/url] [url=http://www.youtube.com/user/c1cl0ps]   - videos !!![/url]

Dayton Kitchens

Member

From: Norphlet, Arkansas

Registered: 2005-12-13

Posts: 183

Re: Whats does NASAs Manned Mars Architecture Look Like Now?

150MT is so that hard, the Ares-V hits 130MT and its the biggest practical rocket to build without serious new infrastructure and having to start from scratch. And razor thin margins are a plan for disaster! What happens if the mission winds up absolutely needing 160MT? You can't make MarsDirect any smaller!

But even then, suppose it does work, MarsDirect will never be good for anything except direct flights with small payloads or crews and no option for growth or upgrades. I also think that the baseline MarsDirect is a bad deal as far as what science you get for the amount of trouble.

I disagree.

As a followup to the basic Apollo program Von Braun had plans for upgrades to the Saturn V that would carry up to 250 tons to LEO and I believe were compatible with the existing KSC facilities.

And once you get a manned program to Mars going with regular flights every 26 months........THEN you find ways to upgrade the amount of men and material delivered to the surface.

You don't try to solve every problem and contingency before even the first flight is made.

Otherwise, we'll never get a manned mission to Mars.

I'm appalled at what I see as the steady growth in complexity of NASAs planning.  Larger crews.  More launches.   Several in space rendevous.

I can't get over someones idiotic reasoning that a mission would have to carry at least TWO surgeons.  Why?  If one needs surgery, the other surgeon can operate on him.

Dayton Kitchens

Member

From: Norphlet, Arkansas

Registered: 2005-12-13

Posts: 183

Re: Whats does NASAs Manned Mars Architecture Look Like Now?

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.

cIclops

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Registered: 2005-06-16

Posts: 3,230

Re: Whats does NASAs Manned Mars Architecture Look Like Now?

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.
.

Salyut had 90 m³ of volume and weighed 19 mT. Yes that's probably about the minimum size of a transit vehicle, so you can save the weight of the happy pills. Calculate the added weight of the propulsion system to move it plus crew, supplies and reentry vehicle back to Earth.

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[color=darkred]Let's go to Mars and far beyond -  triple NASA's budget ![/color] [url=irc://freenode#space]  #space channel !! [/url] [url=http://www.youtube.com/user/c1cl0ps]   - videos !!![/url]

GCNRevenger

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From: Earth

Registered: 2003-10-14

Posts: 6,056

Re: Whats does NASAs Manned Mars Architecture Look Like Now?

Sure if you resuscitated the old Saturn-V and strapped a bunch of Titan-IV solid rockets on it you could hit that figure, but thats not what I would deem as practical; the cost of starting over completely is too high to expect NASA to pay, and really isn't practical. Even if you did, the cost of each huge Saturn-V redux rocket would really not be much less than several copies of Ares-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.

You are appalled huh? Why? I think MarsDirect has tainted a lot of opinions over Mars missions, that Bob's dumb plan is now the gold standard, and everybody else must be piling useless stuff on top... Nonsense! Bob's plan would never work as advertised, you just can't do even his baseline mission with the mass and rockets advertised. So, if you can't pack a Mars vehicle into one rocket, then space assembly then becomes a necessity.

Furthermore, the greatest NASA sin of the last 20 years has been cutting things too close, witness the debacle of the X-33/VentureStar. For Mars, NASA should not be even allowed to work that way, instead making sure to overbuild and overestimate what they think they need. Thus, when weight creep or requirement creep hit, or just if you get lucky and want to pack more science/spares/armor you have capacity left over.

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[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

GCNRevenger

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From: Earth

Registered: 2003-10-14

Posts: 6,056

Re: Whats does NASAs Manned Mars Architecture Look Like Now?

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.
.

Salyut had 90 m³ of volume and weighed 19 mT. Yes that's probably about the minimum size of a transit vehicle, so you can save the weight of the happy pills. Calculate the added weight of the propulsion system to move it plus crew, supplies and reentry vehicle back to Earth.

Nonsense, the Russian Salyut project was a crazy stunt and didn't involve 4-6 people being cramped together after 2.5yrs. Have you ever looked at the floor plan for MarsDirect HAB? Don't forget that the lower level isn't accessible during transit. Its positively claustrophobic, not really any bigger than the Shuttle cabin. And thats the HAB, which is roomie compared to the ERV.

No no, this "SUCK IT UP SOLDIER" attitude is stupid and is a quick way to ruin the practicality and the publics' opinion of the project. This is the same way that Bob in his stupid beyond-the-bone cutting or like the "who cares, he's only a Cosmonaut" Soviets.

NASA's DRM-III plan is much more sane, plus if the laboratory space were omitted in future models the vehicle would have room for eight! Oh, and the same design can be shared between HAB and ERV unlike MarsDirect, lowering development cost for the crew size you get.

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[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

GCNRevenger

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From: Earth

Registered: 2003-10-14

Posts: 6,056

Re: Whats does NASAs Manned Mars Architecture Look Like Now?

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.

Rubbish! Where do you come up with this stuff?! Thats insane! You have no idea what you are talking about!

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[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

Dayton Kitchens

Member

From: Norphlet, Arkansas

Registered: 2005-12-13

Posts: 183

Re: Whats does NASAs Manned Mars Architecture Look Like Now?

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?

Offline

GCNRevenger

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From: Earth

Registered: 2003-10-14

Posts: 6,056

Re: Whats does NASAs Manned Mars Architecture Look Like Now?

No way, one of the biggest problems with Apollo, and one reason why it was not continued, was because you got so little for what was spent (other than getting there), and had almost no real option for increasing efficiency. The same is true of MarsDirect, that it is like Apollo in that it is just barely enough to get there, and doesn't have any place to go.

I am a fan of nuclear rocket engines, but not in the way that Bob calls for them: you see, conspicuous by its absence is one little detail about a nuclear-powered Ares, which is that the nuclear engine would have to be powered up and fired before reaching a stable orbit.

And that I am not cool with, not at all. A nuclear reactor loaded with fresh fuel is virtually harmless, about as dangerous as a box of Lead, you could walk right up and hug the thing... but after its been powered up, it becomes intensely radioactive, even if you shut it down! And having this reactor come back down on our heads ~90min later is too big of a risk versus the benefits.

Zubrin's Mars base is just a collection of old, cramped, worn out HABs, big deal. We need more than that, and landing all our missions in the same place to make this "base" while ignoring the rest of the planet is ridiculous. Unlike the Moon, with its low gravity and complete lack of atmosphere, long-range "hoppers" aren't as well suited  for Mars, so if we want to go some place the whole mission should be landed there.

The comparison between Soviet lives lost and American ones is silly, and reeks of "Iraq body count" style thinking; we lost more because we risked more, that is not emblematic of either Soviet or American "methodology." And their silly "endurance records" are nonsense, propaganda stunts that left many of the Cosmonaut victims scarred for life. Not to mention the virtual imprisonment they went through.

Yes, its absolutely insane to talk about stuffing 4-6 people into a dinky overgrown closet of the ascender.

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[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

cIclops

Member

Registered: 2005-06-16

Posts: 3,230

Re: Whats does NASAs Manned Mars Architecture Look Like Now?

The Mars Direct Program is upgradable.

Mars Direct is unworkable. It requires enormous lift capacity, Ares V won't be anywhere big enough. It's too expensive to carry the return vehicle and supplies to the surface of Mars. They have to be left in Mars orbit. Even the Lunar architecture leaves the return vehicle in orbit and it has a far less demanding requirement for Earth return.

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[color=darkred]Let's go to Mars and far beyond -  triple NASA's budget ![/color] [url=irc://freenode#space]  #space channel !! [/url] [url=http://www.youtube.com/user/c1cl0ps]   - videos !!![/url]

Dayton Kitchens

Member

From: Norphlet, Arkansas

Registered: 2005-12-13

Posts: 183

Re: Whats does NASAs Manned Mars Architecture Look Like Now?

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.

GCNRevenger

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From: Earth

Registered: 2003-10-14

Posts: 6,056

Re: Whats does NASAs Manned Mars Architecture Look Like Now?

We risked more people than the Soviets have, doing what is irrelevant if you are just talking the number of people who have died. More astronauts, more astronauts killed.

Skylab as a Mars vehicle? Not an awful idea, but I am dubious about its reliability... but anyway, Skylab can't land, so its usefulness is dubious in this role. A nuclear-powered upper stage for Saturn would have the same problem as nuclear Ares, that it would not be safely in orbit before the reactor would be powered up. Plus, the upper stage requires even more thrust than Ares, which means either a really huge or a cluster of smaller nukes, increasing risk proportionately.

A bunch of HABs spread 500mi from each other is even more silly, the worst of both worlds, forcing missions to set down within a given radius of each other plus have traversable terrain (so much for studying craters!). And thats road miles, not miles as the crow flies. And what do you get? A worn out HAB with a mostly spent reactor and little food/water. Big deal. And 500mi apart isn't a "base" at all by any sense of the word, you can't bring a heavy drill on mission, a permafrost extractor on another, or anything like that if you land so far apart.

If something goes wrong, the obvious thing to do is get in your MAV/ERV. I mean, obviously!

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[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

dicktice

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From: Nova Scotia, Canada

Registered: 2002-11-01

Posts: 1,764

Re: Whats does NASAs Manned Mars Architecture Look Like Now?

How about this, as a first Mars expedition: send a Skylab type of out-and-return vehicle to polar orbit Mars without landing anyone, but send down any of a number of clever rovers in logical order of capabilities which can be operated remotely from orbit in realtime (having dispersed relay satellites around the planet beforehand. Think of all the research that could be done quickly at nothing like the risk of landing, etc. etc. just to survive and return bedraggled from the surface. The next expedition following on in two years could be devoted to the first landing and surface survival experiments. A Mars version of Apollo 8 followed by Apollo 11 all over again?

Dayton Kitchens

Member

From: Norphlet, Arkansas

Registered: 2005-12-13

Posts: 183

Re: Whats does NASAs Manned Mars Architecture Look Like Now?

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?

ftlwright

Member

Registered: 2004-11-17

Posts: 61

Re: Whats does NASAs Manned Mars Architecture Look Like Now?

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?

Please listen to GCN.  The skepticism he present is a strong part of the engineering process; if your ideas can't get pass this sort of critisism it will never become workable.  Further, the Russians lost may valuable ground crew members during their failed launch attempts; do not discredit there contribution.

Zubrin has done little more than say "we'll add a nukeclear rocket later" with no real study into integration, environmental consideration or development cost and schedule.  It is not worth mentioning and should be irrelevant when discussing the merrits and shortcomings of Mars Direct.

The reason a 6 mo return trip would be unacceptable for a 500 day mission where only have the time is spent in a non-zero g environment should be obvious.  The body of work regarding the effects of long-term microgravity (as well as prolonged exposure to radiation) are to immature.  Further, the very nature Mars Direct give the astronauts NO 'abort' option other than a cyanide capsule.  If the astronauts can not be return with minimal effect to their health than the cost are too high.

I personally would love to see a clean sheet rocket (more interesting work for me), but the reality is the general public would not have the attention span to endure the cost and time of such a project.  We are competing with iPods, celebrities and other areas of science that have a more direct impact on the well being of most individuals.

Though you are 'annoyed' by the assurance of astronauts safety, it is a moral obligation of those of us who have chosen to make engineering career.  There are alway risk, but ALL reasonable measures should be taken to mitigate the risk to the personnel involved.

In-situ fuel production.  It may work, but the mission design should progress as though it will not be feasible.  It is hard enough to build, test, prep and launch a rocket here on Earth; try adding the complexity of doing so 0.5 to 2.5 AU away?  Good luck.  At best (from an engineer stand point) your launching a Falcon I; more than likely you'll be launching something akinned to the Atlas V or the stick.  Fun!

Space exploration is hard, there are no clever shortcuts that will make it easier.  The complexity is there to mititgate risk to crew and personnel, not to inconvience them.  Mars Direct would be more palpable for a sample return mission AND would prove techologies that can be adapted to a manned mission

GCNRevenger

Member

From: Earth

Registered: 2003-10-14

Posts: 6,056

Re: Whats does NASAs Manned Mars Architecture Look Like Now?

How about this, as a first Mars expedition: send a Skylab type of out-and-return vehicle to polar orbit Mars without landing anyone, but send down any of a number of clever rovers in logical order of capabilities which can be operated remotely from orbit in realtime (having dispersed relay satellites around the planet beforehand. Think of all the research that could be done quickly at nothing like the risk of landing, etc. etc. just to survive and return bedraggled from the surface. The next expedition following on in two years could be devoted to the first landing and surface survival experiments. A Mars version of Apollo 8 followed by Apollo 11 all over again?

Nah, remote control of robots from Earth isn't that bad because they are inherently so slow, you wouldn't gain that much by saving the time lag.

Look, Saturn and by extension SkyLab are long, long gone. They are not going to come back. The cost to rebuild Saturn would be about as much as going clean-sheet, which NASA doesn't have the money for. Since Ares-V is only two stages, a Skylab like ship makes less sense too.

Even if we did, Saturn was a ruinously expensive rocket. The old F-1 engines and the -six- J-2's would really add up.

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[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]

GCNRevenger

Member

From: Earth

Registered: 2003-10-14

Posts: 6,056

Re: Whats does NASAs Manned Mars Architecture Look Like Now?

If absolutely necessary, I could go with the "Mars Semi-Direct" option.

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.

If they willing to risk it, then why can't we on the ground?

I think, that without a really huge and prohibitively expensive rocket that "SemiDirect" of some type is the way to go. It offers qualitatively more capability, more comfortable margins, and thanks to its modularity gives it options for upgrade. It also offers the best combination of a rocket capable of doing the mission in a reasonable number of launches but also requires launch often enough to keep the rocket lines from sitting idle too long.

There is no orbital assembly under "SemiDirect," but there are quite a few dockings: the original DRM-III plan actually calls for six flights of a "Ares-IV" light duty heavy lifter, which could be (my idea) a shorter version of Ares-V with four RS-68's, four-segment boosters, and no EDS stage. One for each Mars ship (HAB, MAV, ERV) and one nuclear booster for each ship, attached by simple docking in LEO.

Yes that is a lot of rockets, but leaving the ERV in orbit and launching up to it in the ascent vehicle only cures the ERV from being too small and too weak. The HAB (or for that matter, any surface payload) are not improved. Also, since the biggest expense of each launch is man power, each launch would cost somewhat less as the number of launches increases.

And nuclear rockets are required for the baseline DRM-III plan, but I have a solution: instead of the 90MT nuclear rocket, instead launch an enlarged 130MT Lunar EDS stage, which makes up the difference approximately between chemical and nuclear engines.

If not, or if more performance is desired, launch both the "super EDS" and the Mars ship on two Ares-V's instead of one -V and one -IV, but put the Hydrogen on the Mars ship and the Oxygen on the EDS. (increases TMI mass by ~10MT) This option also eliminates the boiloff problem of LEO loitering.

And I think six people make a good sized crew, enough so you could get more done in a single landing. The eight-man crew example is as a growth option for "SemiDirect," some time down the road when we have a Mars base. Four people is kind of small, particularly if one or two of the crew will be kept busy by maintenance tasks or whatnot.

The upgrade path I have in mind goes as follows: Martian water extraction is set up so that the Mars base has an unlimited supply of rocket fuel. At this point, a fully reusable ascent vehicle is built for ferrying crews (up to 8 ) or light cargo (10MT) to/from Martian orbit. The ERV is modified for long term use (multiple trips) and the heat shield improved to withstand aerobraking into Earth orbit.  The ERV would then be used as a Earth/Mars cycler, picking up a crew, a load of fuel for the return trip, and a new TMI booster. It would then travel to Mars orbit, exchange crews, and return home to Earth orbit. A total of two heavy or one heavy and one medium-heavy launches per sortie.

Gold plating? This is exactly what I was talking about concerning how MarsDirect has tainted the debate over what is really the minimum bare-bones Mars mission. Its not "gold plating," its the actual lower limit of what is practical, effective, and worthwhile.

And please, we aren't going to let a bunch of Lemming astronauts line up to go on a rocket that will get an inordinate number of them killed. We're not going to indulge the psuedo-suicidal lot.

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[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]

[i]The glass is at 50% of capacity[/i]