Going to Mars w/ Ares I and V... What else do we need?

Rxke · 2006-08-18 01:15:14

Soooo...

Let's assume Ares I and V are built, are a huge succes, we go to the moon and do our stuff.

And then decide to take the next step. Mars!

We'd already have a lot of hardware developed, but not all of it, so what else, besides Ares I and V, cargolanders etc. would we need to develop to get to the next step?

Would we need a spinning craft for artificial gravity? What about heatshields and communication, food and power enroute etc... What kind of unmannded precursor missions do we still have to do?

What would prove to be the biggest stumbling-block?

GCNRevenger · 2006-08-18 16:58:29

Building the vehicles themselves without the budget getting out of control. "Absolutely must work or everybody dies" aerobraking especially.

RobertDyck · 2006-08-20 00:56:57

We need to demonstrate ISPP. Mars 2001 Lander was going to have an ISPP precursor, it was cancelled but frankly I thought it lame. It would have only produced oxygen, no fuel. We need a complete demonstration of the entire cycle: launch, land, produce fuel, launch from Mars, return to Earth, land. That means a sample return mission. Some Mars Society members don't want it because they think it's competition for a manned mission, but I see it as an ISPP demonstrator. As a technology demonstrator it's a precursor.

The last few landers have used direct entry, they didn't orbit Mars they just went straight in. That was used for Mars Pathfinder, the two Mars Exploration Rovers (Spirit & Opportunity), was tried for Mars Polar Lander, and will be used for Phoenix. We haven't demonstrated aerocapture into orbit. Mars Global Surveyor used propellant to enter orbit, then used aerobraking to lower its orbit. That was used again for Odyssey, and most recently by Mars Reconnaissance Orbiter. Mars Climate Orbiter tried aerocapture, but they had the metric conversion error. We need to demonstrate aerocapture.

I don't see artificial gravity as a major stumbling block. Shannon Lucent spent 6 months on Mir and walked off the Shuttle in 1 full Earth gravity. It takes 6 months to get to Mars, good enough. Ms. Lucent exercised a couple hours a day every day while in space; Mars astronauts would have to do the same but they won't have much else to do until they get to Mars. If you want to use artificial gravity you will have to demonstrate the ability to manoeuvre. I suggested doing it in Earth orbit. Use a spent Progress cargo ship filled with garbage from ISS, and a Soyuz spacecraft. Connect them via tether then make some orbit changes. It doesn't matter what changes, just prove you can. If something goes wrong cut the cable, each spacecraft has a service module so they can manoeuvre separately. The Progress will be destined to burn up in Earth's atmosphere anyway, and the Soyuz could ditch and return to Earth. Or do it with an ATV and CEV.

Life support. ISS uses electrolysis of water to generate oxygen. That recycles half of the oxygen astronauts breathe. A regenerable cabin sorbent scrubs out CO2, that CO2 and hydrogen from electrolysis are dumped in space. To generate enough oxygen, water is shipped from Earth. Water only requires a bag to hold it, and the hydrogen in water weighs less than a heavy tank for pressurized oxygen, so in orbit it's worth it. But you can't ship enough water for a 2 year trip to Mars and back. NASA proposed adding a Sabatier reactor to convert all the hydrogen and half the CO2 into methane and water. That would provide enough water for the electrolysis tank, it would recycle oxygen. Unfortunately they thought of it after the US habitation module for ISS was cancelled. NASA got the idea from Robert Zubrin's ISPP device for Mars; instead of producing fuel they want to produce water for life support. From this I got the idea of using the direct CO2 electrolysis device from Mars 2001 Lander to extract some oxygen from the other half of the CO2 that would have been dumped in space. It's power hungry, consuming 2 1/2 times as much power per kg of oxygen as water electrolysis, but will replenish oxygen recycling losses. Since water electrolysis generates oxygen, you can dial down water electrolysis and dial up CO2 electrolysis to replenish water recycling losses. The source is dry carbohydrate in food. This means you ship up dry food and dehydrated food only, water and oxygen are recycled. Replenishing this way only works if recycling is very good, so you need the Sabatier reactor and a good water recycling system. That means a toilet that recovers moisture from feces, and recycling wash water. NASA was planning on that too. I've argued we need to test all this on ISS. GCNRevenger argued for testing in a Bigelow habitat. Either way, it has to be tested in LEO for the same duration as a complete Mars mission.

We also need a good spacesuit. Many people push the Mark III hard suit; I think it's good enough for the Moon but not good enough for Mars. I argue for an MCP suit. I also argue for a head-worn helmet build as a crash helmet, especially if they use an open rover.

I think I've run out of things. After that it's just a matter of engineering the vehicle.

GCNRevenger · 2006-08-20 11:20:27

I don't see a good reason to test ISRU technology on Mars, if all its going to do is suck up Martian gasses to make water/methane/oxygen then we can simulate those just fine here on Earth, better and cheaper. Of all things, gasses don't care if there is gravity or not.

I don't think there is any point in bothering with learning to maneuver while using the spinning tether artifical gravity trick. Alligning the engines properly would be difficult to do well, and if you are cruising to/from Mars then there isn't really a good reason to barring an emergency course correction.

"I've argued we need to test all this on ISS. GCNRevenger argued for testing in a Bigelow habitat. Either way, it has to be tested in LEO for the same duration as a complete Mars mission."

I think it should be tested, but neither on the ISS (if that is its sole justification, thats pretty weak) or in an unmanned Bigelow hab, but rather on the actual prototype Mars ship launched into Earth orbit for testing. Have a crew sent up by CEV to live onboard, test all the systems as an integrated whole, bring up/down systems for testing by cargo CEV, etc.

I agree that present pressurized soft and rigid hard suits planned for the Moon won't do for Mars, MCP suits are the obvious choice.

We are also going to need a portable nuclear power plant for Mars most likely, solar is not good enough.

RedStreak · 2006-08-20 20:37:58

I think what would need to be developed are the Mars vehicles. Beyond perhaps propellant tanks they will be creatures of a different sort from any on the Moon.

I'd like to model the architecture as much as possible off the Mars Semi-direct architecture Zubrin created as a "compromise" that later led to NASA's "Reference Mission." I can see the CEV as being the orbiting ERV from Semi-d; I think however we'd have to recalculate how much propellant it'd need for the return half of the voyage where it'd come into play.

The Mars Habitat could be the initial manned lander brought along with the CEV and then there'd be the Mars Ascent Vehicle, which in Semi-d brought the ISSP equiptment and power sources.

If the CEV were to be 'blended' with Semi-d, upon arriving at Mars it'd most likely have to seperate and break into a high parking orbit automated and solo (which it is capable of) while the Mars Habitat Lander first aerobrakes and then lands with the crew with it. In both Semi-d And Mars-d, should something happen to the ERV the crew wait on Mars in relative safey doing field research as opposed to the complete vaccum of space doing nothing, so if CEV blows in orbit just send another. The Mars Ascent vehicle would be closer in aspect to the original version in Mars-d to reach the high parking orbit and draw on ISSP to maximize its use while minimizing the ERV/CEV's propellant loads for orbital breaking and escape.

To test some of this, a large test probe carrying at least a model of the Crewed Mars Lander shields ought to be sent; to aerobrake first into orbit and then land from orbit. Possibly an unmanned CEV could be sent to test break into Martian orbit and then leave as well.

GCNRevenger · 2006-08-20 20:46:31

CEV is way too small. The surface habitat should be copied and the landing hardware substituted for larger fuel tanks needed to return from Mars orbit to Earth. The CEV capsule itself could serve as the base for the acent vehicle however.

SpaceNut · 2006-08-20 20:54:39

Life support. ISS uses electrolysis of water to generate oxygen. That recycles half of the oxygen astronauts breathe. A regenerable cabin sorbent scrubs out CO2, that CO2 and hydrogen from electrolysis are dumped in space. To generate enough oxygen, water is shipped from Earth.

If we were smart rather than dumping this over board we would be creating methane from this and using a methane power fuel cell to reburn it. Thus wasting less of these materials and getting some experience in methane production, plus power and more water by doing so.

Liquid Methane powered engines That might be used to get use into reusuability. Yes they are Russian but start and convert over to US made once we have license to make them.

RedStreak · 2006-08-20 21:09:59

The CEV capsule itself could serve as the base for the acent vehicle however.

That I certainly would agree upon. Another question is would it be nessicary for the Ascent Vehicle to have heat shields, would it be expendible at Mars or double as the return vehicle to Earth?

RedStreak · 2006-08-20 21:16:39

A criteria to consider would be the Martian heatshields. In the VSE architecture one bonus the CEV capsule has over the shuttle, and like the Apollo for that matter, is that the heat shields were protected. Now, I noticed, in most architectures, even in Zubrin's renowned Mars Direct, the heat shields are wide open for anything ranging from LEO space junk to metoroid showers to punch a crack.

This is a worry that will HAVE to be addressed; not so much because of engineering but because the media press, with the CEV specs in mind, will, like naively-blunt Kindergardners, almost instantly point to the big fancy heat shield being toted at the front of the Mars armada and embarass the hell out of the NASA engineer stuck in the hot seat.

RobertDyck · 2006-08-20 23:01:02

A criteria to consider would be the Martian heatshields. ...in most architectures ... the heat shields are wide open

There are ways. First, the atmospheric entry capsules for Mars Pathfinder, Spirit, Opportunity, Mars Polar Lander, and Phoenix all were (will be) exposed to space. They worked, the problem was Pathfinder's battery froze, and Polar Lander failed to land. I'm told simulations showed unfolding legs tripped the ground contact switch sometimes, and that switch caused the computer to turn off the landing rocket. So Polar Lander fell a hundred feet or so and crashed. None of these had heat shield problems.

Another issue is the heat shield is more durable than the 1960s. It isn't made the same way. One reference said the Apollo ablative heat shield is a honeycomb of stainless steel filled with pheonolic epoxy resin. Another said a mixture of epoxy and telfon sandwiched with layers of cork. I'm not sure what they used for the Mars landers, but after Apollo was cancelled NASA developed an ablative ceramic. A more durable heat shield developed for a next generation shuttle was metallic. It was inconel sheet metal with layers of inconel foil crumpled beneath, attached to a titanium hull. It sounds pretty durable to me. A soft material later developed is inconel foil over a quilt of nextel 440 fabric filled with saffil batting. But reusable heat shield materials aren't applicable to direct entry from interplanetary velocity. From this I did come up with an idea for aerocapture; if the vehicle is only entering orbit and not descending, then temperature and stress won't be as great. Use nextel 440 fabric over an umbrella-like frame. But for Mars Direct or whatever the lander may be, use the same stuff we already sent to Mars. Pa Kettle: "If it ain't broke, don't fix it." Or did he use "i'tain't" instead of "it ain't"? I've heard quotes but never saw that show myself.

RobertDyck · 2006-08-20 23:23:31

If you like alternate architectures, look at my presentation from the 2005 Mars Society conference, Mars Orbit Rendezvous. It's a .ppt file so you need PowerPoint to view it. If you click on it you'll see only slides. Right click and save to disk, then open. View the notes pages to see what I said. The point is to minimize stuff lifed off Mars, but it results in a reusable orbit-to-orbit spacecraft. It would need a capsule as an emergency escape pod, but that has to be minimized. A Soyuz descent module or the descent module from Northrop Grumman's original CEV proposal would do. The CEV as currently proposed is sized for a lunar mission; too big for an emergency escape pod.

Yang Liwei Rocket · 2007-05-26 05:04:07

They need to do human test or precursor missions testbedding if they can land robots in on Mars, launch them back up and return them to Earth.

Many Astronauts also need to be kept in a stable, zero-g enviornment for a while like the Russians did with their year-long stays on MIR. ISS even though it has the ability to be a great station has never lived up to the record breaking humans spaceflight in MIR, and the ISS crew has been minimal. It's time to increase the crew on the ISS and push for long duration flights, not just an up and down trip.

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#1 2006-08-18 01:15:14

Re: Going to Mars w/ Ares I and V... What else do we need?

#2 2006-08-18 16:58:29

Re: Going to Mars w/ Ares I and V... What else do we need?

#3 2006-08-20 00:56:57

Re: Going to Mars w/ Ares I and V... What else do we need?

#4 2006-08-20 11:20:27

Re: Going to Mars w/ Ares I and V... What else do we need?

#5 2006-08-20 20:37:58

Re: Going to Mars w/ Ares I and V... What else do we need?

#6 2006-08-20 20:46:31

Re: Going to Mars w/ Ares I and V... What else do we need?

#7 2006-08-20 20:54:39

Re: Going to Mars w/ Ares I and V... What else do we need?

#8 2006-08-20 21:09:59

Re: Going to Mars w/ Ares I and V... What else do we need?

#9 2006-08-20 21:16:39

Re: Going to Mars w/ Ares I and V... What else do we need?

#10 2006-08-20 23:01:02

Re: Going to Mars w/ Ares I and V... What else do we need?

#11 2006-08-20 23:23:31

Re: Going to Mars w/ Ares I and V... What else do we need?

#12 2007-05-26 05:04:07

Re: Going to Mars w/ Ares I and V... What else do we need?

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