A "Quick & Dirty" Manned Mars Mission - How Would We Do It?

Dayton3 · 2004-11-23 18:40:52

Say that in his 2006 State of the Union Address, President Bush announced that he wanted NASA to launch a manned mission to Mars by 2010....how would we do it?

Assume we had no notable advance in spaceflight technology over what we have now.

Assume a crew of 4 minimum-6 maximum.

Assume no major new launch systems.

Assume that NASA sets the acceptable risk for astronaut death at roughly 10%. (the risk estimated for the Mercury missions).

Could it be done? Could it be done with no significant increase in funds by redirecting the existing NASA budget?

I'm thinking a quick and dirty one off mission might be the best way to get to Mars in any reasonable amount of time.

And isn't this basically the method envisioned in Dr. Zubrins "First Landing" novel? I figured it was given that he had his characters come via a Venus flyby (not in true Mars Direct).

GCNRevenger · 2004-11-23 18:59:55

"Assume no major new launch systems."

If by which you mean no new launch vehicles, that we would be limited to those currently in production without alteration, then the answer would definatly be "no."

SpaceNut · 2004-11-23 19:28:50

That would probably also mean an in orbit of cludged together pieces. That were never meant to be put together in the first place.
examples
Manned capsules available other than a soyuz the only other is a chinese look a like. Duration not available with out additional modules from probably newly design Iss modules to act as command module and living quarters. Booster to power it to mars would be expanded pieces of the russians progress or soyuz, Atlas and Delta modular pieces restack to get them to orbit.
As you can see we have nothing except pieces..

GCNRevenger · 2004-11-23 19:35:33

Its more of a matter of mass then anything really, that American rockets couldn't possibly launch enough payload to make it to Mars in that short of a time frame. We could launch maybe 200MT a year with current rockets, and it would take time to build the Mars ships even if we had a design today.

Dayton3 · 2004-11-23 20:03:05

How hard would it be to cobble together a "Mars Direct" style mission by modifying existing hardward?

For example, how difficult would it be to build a large booster by attaching four SRBs to a modified External Tank and mounting an upperstage on the top that uses existing rocket engines?

For that matter, how hard would it be to build a slightly altered version of existing ISS modules to serve as the "Hab" for transit to Mars and as living quarters there?

Lets say you diverted half the budget of NASA for 4 years or so. Surely you could do alot with 32 billion dollars (6 billion per year).

I like Dr. Zubrins statemnt "In the real world, you can buy alot with a billion dollars".

SpaceNut · 2004-11-23 20:11:33

Well here is just what you are proposing but for the moon.
A trip around the moon? It could happen

Mark S · 2004-11-23 20:20:50

I would prefer to not think about a "cheap and dirty" Mars mission. I would rather spend the time and money doing things correctly.

As it stands, I consider Mars Direct to be the cheapest, dirtiest Mars mission that is viable. If Mars Direct were to be improved, I would start by
1) replacing the chemical TMI stages with nuclear thermal ones
2) expand the crew compliment to six
3) use a truss for artifical gravity,
4) use either a bigger booster or break the ship down and use two Shuttle-C type boosters, and
5) go to a semi-direct architecture with a Mars-orbit rendezvous.

GCNRevenger · 2004-11-23 20:34:51

Making a Shuttle-derived superbooster is harder then it sounds, even Shuttle-C would probobly be a multibillion dollar investment, and it will have high per-launch costs.

I like the idea of break the mission into at least six launches, which can be done in the space of about a year. One ERV that stays in LMO, one surface payload w/ acent vehicle, and the HAB/lander. Each payload would be pushed to Mars by a separate TMI stage, probobly chemically powerd to avoid the expense of nuclear engine (re)development & politics.

BWhite · 2004-11-23 22:44:26

"Assume no major new launch systems."
If by which you mean no new launch vehicles, that we would be limited to those currently in production without alteration, then the answer would definatly be "no."

Here is one scenario:

http://www.livejournal.com/users/father … remeagwali

I use Thiokol 5 segment RSRMS plus LH2/LOX upper stages for this scenario but I believe the Russian Proton would work as well. (Elden Smith is my creation, btw)

Dayton3 · 2004-11-23 23:26:32

I would prefer to not think about a "cheap and dirty" Mars mission. I would rather spend the time and money doing things correctly.

Wouldn't we all. But I think this is the trap alot of us space enthusiasts fall into. Thinking that we'll get a multi-decade, multi billion dollar program that methodically advances us into space fueled by an enthusiastic public.

In reality, I think any exploration beyond Earth orbit will have to be a series of "stunts" that we lobby for each individually.

Mark S · 2004-11-24 00:56:59

In reality, I think any exploration beyond Earth orbit will have to be a series of "stunts" that we lobby for each individually.

My hope is that a series of successful "stunts" like the X-Prize and the Bigelow Prize will convince people that space is here to stay. At some point, "the powers that be" must observe that space is not a stunt, but the future of mankind.

SpaceNut · 2004-11-24 05:43:13

NASA's budget bump

NASA must be held strictly accountable on how it spends the funds, to prevent a repeat of the mismanagement that has plagued such programs as the International Space Station and caused huge cost overruns.
That's why Congress has put the agency on a short leash, which is were it should stay because of the complexity of the moon-Mars goal and its poor track record the past 30 years in meeting budget projections and schedules on major projects.

Over coming a few Hurdles one by one proving themselves first by the robotic Hubble repairs followed and by deal with rising costs to make safely fixes on the aging shuttles.

Congress also has correctly demanded that an independent committee oversee development of the CEV a new spaceship under the exploration plan.

RobertDyck · 2004-11-24 09:56:20

The simplest, quickest means to send humans to Mars is Mars Direct split into 3 launches instead of 2, and use the Russian Energia. That requires restoring manufacture of the tanks for the core stage, and rebuilding the vehicle assembly building. Although Michoud could build the tanks, I doubt congress would going with a Russian launch vehicle.

We could develop a self-launching spacecraft; that means the interior of what will be the Interplanetary Transfer Vehicle will be the propellant tank for the sustainer stage. It would only be as big as Atlas D, the one used for Mercury. That would require interior furnishing to be unpacked from a separate cargo module and installed, and a TMI stage to be added on-orbit. A couple Delta-IV upper stages couple serve for TMI, each requiring a Delta-IV Large to launch. All this means on-orbit assembly. You could replace the Delta-IV upper stages with a single Timberwind 45 stage, but that's nuclear and would require development. The self-launching ITV would be a new vehicle, so it would also require development.

Mars Direct with 3 launches could use a Shuttle-C, but that would require development.

You could assemble entirely on-orbit using Shuttle to lift a TransHAB for the hab, and again a couple Delta IV upper stages for TMI each requiring a Delta IV Large to lift it. The ERV would require another Shuttle launch and a couple more Delta IV upper stages for TMI. I say "a couple" because I haven't calculated TMI requirements. This means multiple Shuttle launches and several Delta IV Large.

Dayton3 · 2004-11-24 10:20:41

What kind of price tag would we be looking at for a large booster. Say Ares type that Dr. Zubrin preferred?

I don't understand why it need be so expensive.

I heard it estimated that if they really put forth the effort, they could have an Ares type booster built for only one billion dollars within about a year.

SpaceNut · 2004-11-24 11:19:08

Well here is the link to the Astonautix site

http://www.astronautix.com/lvs/ares.htm

A SDV using modified existing hardware.

Current External tanks 40million probably another 10 once modified but maybe 500million to come up with the modifications

I think SRB 30million which would be twice the thrust of the Asrm unit

Upper stage I will not even venture but it should be less than 100million possibly a stretched section from the Atlas5 or deltaIV systems modified maybe 500million to develop

These are all just guesses on my part.

I think the Ariane V would be also a good starting point.
http://www.arianespace.com/site/index2.html

Long and short of it thou is we still have nothing for the crew only cargo, supplies, fuel and water.

GCNRevenger · 2004-11-24 12:28:54

I really don't like the idea of stacking multiple Centaur stages up to build a makeshift TMI stage. Its a bad idea from the start, multiple engines, multiple small tanks, and the biggie: that you can't launch them fast enough to avoid LH2 boiloff. Using only one TMI stage, launched shortly after the astronauts have checked out the vehicle and are ready to depart, is clearly the best strategy for a multi-launch Mars vehicle. It will also eliminate much of the need for orbital assembly if the vehicle can be held to two or three pieces (maybe four). This also rules out any Shuttle SRB or Delta-IV HLV medium launcher option; they are just too light.

I don't like this idea of the ITV, the tankage itself doesn't weigh a horrible amount, and it would not be armored against debries or shielded from radiation, which will take up alot of mass of whatever crew cabin you build. Internal construction in zero-G is also no fun, and should be avoided. TransHab with most of the hardware and furnishings in the core structure with water bladder/doped polymer lining, topped off with a hardening polymer in the outer later, is the best choice.

I think the half-billion dollar estimates for a "Shuttle Conversion" are much too optimistic, it will no doubt be a ten-figure operation given how inefficent the Shuttle Army is. Using the SSMEs and Shuttle OMS engines are also not a very good option, and a new engine pod based on improved RS-68 "R" engines paired with the improved 5-segment SRB boosters probobly would be the best balence between development, payload, and flight costs.

That would give you about 100MT to orbit for the lowest cost probobly... if you need an upper stage for the vehicle, I don't think that the little RL-10 engines are powerful enough for that. Even the RL-60 may not have enough kick.

Resurecting Energia with American money isn't going to happen even if Russia could build the Vulkain model (which they never did).

RobertDyck · 2004-11-24 13:01:33

"Resurecting Energia with American money isn't going to happen", you're probably right. NASA has no objection, they just want the best vehicle for the best price; however congress wouldn't go for it.

"I think the half-billion dollar estimates for a "Shuttle Conversion" are much too optimistic, it will no doubt be a ten-figure operation given how inefficient the Shuttle Army is." No argument.

I had originally thought of using a TransHAB style design for the reusable ITV. It would travel from Earth orbit to Mars orbit and back. Janyce Wynter told me of self-launching technology. The idea is to purpose build a vehicle to be a self-launching space station or ITV. That means you add a micrometeor shield, radiation shield, and make thermal insulation last longer than the few minutes of a launch. A self-launching vehicle is much more robust than a typical launch vehicle. Floors and walls would be installed before launch, and just like the Skylab workshop, designed to permit propellant to flow through easily. Parts that can't handle cryogenic freezing or small parts that could shake loose during launch would be stored in a payload module. Bolting a chair to the floor or snapping a laptop computer into clips on a wall are easy. If the crew can't handle simple internal construction they won't be able to maintain the equipment during a Mars mission.

I also agree that a single TMI stage is preferred. I did say a Timberwind based NTR stage would be better; since you like nuclear you should like that. But the question was how to do it without new development. Multiple Delta 4-2 stages (a bit bigger than Centaur) are available now and the maximum that a Delta IV Large can lift. It's not ideal but could be done.

GCNRevenger · 2004-11-24 13:44:07

"Robust" by which you mean "does not weigh as much"

"Self launching" (which is a misleading term to begin with) isn't so much a technology (which sounds new, innovative, superior) as it is an old strategy to try and save a some launch weight.

I think that its a bad idea, fuel tanks and crew cabins are fundimentally different structures, and trying to combine the two will surely result in inefficency in both purposes.

First off, it would be too small. The crew cabin will have to be signifigantly bigger then, say, an ISS module to keep the crew sane. This is one of the major and fatal failures to Bob Zubrin's MarsDirect mission arcitecture.

Micrometeoroid shielding for TransHab can be thick foam because it is is inflatable, but you can't use this light weight option very well on a metal rocket stage without increasing its launch diameter and hence air resistance. Similar deal for radiation shielding, which should be multiple centimeters thick... Adding a meter to the diameter of the vehicle reduces the Atlas-V payload by several tons. Oh, did I mention that soft impact armor offers better protection then metal?

If doped polymer radiation shielding is selected, it cannot withstand cryogenic temperatures without becomming pretty brittle, which you don't want for the rocket. The same deal with most coatings on the inside surfaces of the vehicle; even if you get paint chips sucked into the turbopump... kaboom.

Other things you can't put in the tanks that you have to launch and have astronauts install:
-Basic wiring, electrical power, data, etc
-Internal walls, turbopumps use vortexs to draw in fuel faster without turbulence, obstructions are unacceptable
-Internal lighting
-Optical windows
-Internal plumbing for food prep, hygene, LSS probobly will require installation
-Tables, chairs, excercise equipment
-Toilet, shower, kitchenette
-Air ducts for closed rooms(?)
-Bulk storage cabinates
-Beds
-Laboratory equipment for sample handling
-Other things I haven't thought of yet

There is so much STUFF by volume that would need to be launched seperatly in its own cargo container, that you can put in the TransHab modules that you can't put in a tank full of ultracold liquids subjected to strong vibrations, that its a better idea to make a purpose-built module thats a little bigger with the stuff built in.

I really can't emphasize enough that the Mars vehicles must NOT be ruled by mass concerns, in this respect Zubrin is foolish, that if the price of robustness of the mission - reliability, capability, safety - is higher launch weight, then the problem is not with the vehicle being too heavy, its the launcher being too weak.

GCNRevenger · 2004-11-24 13:49:58

"I also agree that a single TMI stage is preferred. I did say a Timberwind based NTR stage would be better; since you like nuclear you should like that. But the question was how to do it without new development. Multiple Delta 4-2 stages (a bit bigger than Centaur) are available now and the maximum that a Delta IV Large can lift. It's not ideal but could be done. "

Not even Timberwind has a high enough specific impulse to push a Mars vehicle with a single Delta-IV HLV worth of fuel.

The problem with stacking multiple heavy duty Centaur stages is the boiloff primarily, that the big Delta-IV simply can't launch fast enough, there wouldn't be much if any fuel at all left by the time the 2nd Centaur is brought up. Fuel must either have boiloff protection or be deliverd within a month or so of use. Then you have the reliablity and control issues of multiple Centaur engines, and starting them up after months in the cold/hot soak of space. They would have to be modified too, they are after all only battery powerd.

~Eternal~ · 2004-11-24 14:28:07

Perhaps a shenzhou-like craft would be good for a trip to Mars, given an extra module between the re-entry module and the orbital module.

This extra module would rotate giving 1/2 the gravity of Earth containing supplies to get there and living quarters.

Before the mission takes off though, some things would have to be sent to Mars already, namely : an ERV, a Hab, and supplies.

RobertDyck · 2004-11-24 14:33:06

"Robust" does not mean "does not weigh as much". A robust vehicle is more durable and usually weighs more. That means a self-launching vehicle weighs more than a typical launch vehicle, but the fact that the spacecraft is not separate means the total of launch vehicle plus spacecraft weighs less.

The Skylab workshop was designed to be a self-launching space station. It's the baseline I'm using. The Apollo telescope mount, multiple docking adapter and airlock were added after the decision to use a Saturn V instead of Saturn IB, but the workshop was the same. The hydrogen tank was the living space, the oxygen tank was used for garbage and the toilet emptied into it. Floors and ceilings were open grids to permit hydrogen flow, walls were solid.

You can install electrical wiring in a cryogenic oxygen tank if insulated with teflon. Teflon is the superior form of electrical insulation, but it still won't handle hydrogen's temperature.

Optical windows: use polychlorotrifluoroethylene (PCTFE) instead of polycarbonate. It's a fluoropolymer similar to Teflon and can handle -240°C, liquid oxygen is -182°C. So that means install windows in the LOX tank instead of the LH2 tank.

I think you overstate the radiation shield. A shield that adds a metre to vehicle diameter will be so heavy it'll never be practical. That's why Robert designed his habitat with a radiation shelter; only a small area heavily shielded.

So you're saying TransHAB is better than self-launching. In the end that still means a single Delta IV Large could launch it deflated instead of a Mercury Atlas size self-launching vehicle. Not really that big a difference.

Dayton3 · 2004-11-24 19:53:01

What would be the most expensive part of the Mars Direct Hardware to build?

The Hab module I think would be the most expensive followed by the Earth Return Vehicle.

Now, I think providing alot of space for the crew in the Earth Return Vehicle would be a waste. After all, they can be crammed tighter given the are

1) Coming home. Which will do wonders for their mental state.

2) Be getting closer to Earth, so communications with home will be much quicker the longer the mission draws to completion.

3) The crew will be returning to the ISS (presumably) for a brief quarantine and medical tests. Not to the martian surface for back breaking work all alone. So not as much space needs devoted to keeping them in top physical shape on the return leg.

GCNRevenger · 2004-11-24 23:43:24

No, I think you understate the need for radiation shielding... the more we learn about the hazards of deep space radiation, the more I fear it. The percentage of people exposed to even modest doses cosmic radiation that develop eye cataracts may be in the double digit range. General cancer risks may also be on this scale.

Having essentially no radiation shielding other then a storm cellar is unacceptable; full vehicle radiation shielding consisting of multiple centimeters of water or doped polymer combined with an enlarged aluminum/water storm cellar that the crew would sleep in is called for.

I think that the trouble of cold-proofing and making all the equipment "installable" makes the whole idea pretty impractical. Being a Fluropolymer, is CTFE even transparent? How about the seals between the tank? On top of all the other things you can't mount in either tank... Plus, the LOX tank won't be all that big, no where near as big as the Saturn 2nd stage tank, which might make that section of the vehicle awfully cramped. Take a look at the LOX tank on the Centaur.

Skylab never was the greatest of ideas in my opinion, and nothing like it wouldn't be useable as a Mars ship without extensive modifications and dry volume cargo sent from Earth, particularly if the Hab had to land ala MarsDirect. You might as well go with the TransHab, it won't be more expensive, it won't be that big of a mass penalty, it will be bigger, and it will be safer with its soft-shell armor.

Now a word about the attitudes of crew safety...

I think that there is a prevailing undercurrent/unsaid-philosophy of MarsDirect and proponets of similar that its AOK to "cut corners" with crew concerns in order to make a Mars mission faster/better/cheaper in order to make it more palatible sounding to the accountants and that Mars is "no big deal" to the lawmakers and NASA managers...

That if you can get away with slashing some crew concern, like vehicle volume, by telling the poor shmucks in the tin can to "suck it up, solider," launch with some unacceptable risk on a "volunteer" basis, or the ever popular "so captivated by the pioneer spirit they forget they're stuck in a sardine can!" is a good or acceptable thing.

No, bad, wrong, foolish, etc... This is a BAD attitude to have! The mission should be designed from the core down, not the booster up like Doc Zubrin has. People have definate dimensions and require definite dimensions of space and other physical limitations (zero-G exposure, radiation, etc), and so you design the vehicle around those needs, and then you select the rocket based on that vehicle. NOT the other way around.

The mental state of the astronauts, for example, is not somthing you want to take chances with by cutting the margins close, like is done on MarsDirect. If it takes billions more to accomodate enough space to have non-worrisome margins, then it costs billions more. The price of doing business in manned spaceflight... after all, going to Mars IS a big deal, no matter how much Bob Zubrin & co want it not to be.

RobertDyck · 2004-11-25 01:38:16

Polychlorotrifluoroethylene (PCTFE) used to be manufactured by 3M under the brand name Kel-F. Now its made by a Japanese company which uses the name Neoflon for all fluoropolymers. Its used for blister packs for pharmaceuticals. Ever get pills in a plastic sheet with aluminum foil backing? That plastic is Kel-F. It's very transparent; it transmits 96% of visible light, UV and IR. That makes it more transparent than polycarbonate, or any other plastic. Teflon FEP and Tefzel are almost as transparent, there's less than 1% difference between them, but Kel-F is the most transparent.

I looked at this when researching material for an inflatable greenhouse. Most greenhouse guys want to use Tefzel because it's the premium material used for greenhouses on Earth. Tefzel has significantly higher strength and lower weight, making it appear the ideal material. However, it becomes brittle at -100°C. Viking 2 recorded temperatures for more than a Martian year; it recorded a low of -111°C. You could try to maintain a warm film, but I don't want to trust a material that will break and release pressure if the heater fails. Teflon FEP has been used on satellites, doesn't become brittle until -240°C. Kel-F has the same embrittlement temperature as Teflon FEP, is slightly stronger and lighter, and much more gas impermeable. Tefzel is very impermeable, but Kel-F is much more so. Kel-F is the most water impermeable of any polymer. There are a couple other polymers slightly more oxygen impermeable, but they can't handle the cold of Mars at night. This makes Kel-F ideal for an inflatable greenhouse.

Teflon AF (amorphous fluoropolymer) is the only material more transparent than Kel-F, but Teflon AF has high gas permeability. Teflon AF also has the lowest optical index of any polymer, which means low reflection. This makes Teflon AF suitable for windows over solar panels on Earth, but not for pressure containment in space.

Anyone else reading this will notice something. NASA has had trouble developing a liquid oxygen compatible all composite propellant tank. DC-XA used an all composite LH2 tank, but aluminum-lithium for LOX. That's because graphite fibre is will combust with LOX; the LH2 tank was graphite fibre/epoxy. One engineer at Lockheed Martin told me they have a LOX compatible all composite tank, but didn't say how it's made. He suggested a Carbon Overwrapped Pressure Vessel for LOX; a design that's public domain. COPV uses a thin aluminum tank that's reinforced with graphite fibre wrapped around it. However, a tank could be made with a bladder of Kel-F film overwrapped by graphite fibre. Like any COPV tank it would be susceptible to impact damage, but it would be suitable for internal tanks. You could design a graphite fibre/epoxy tank with a Kel-F liner, but I think a Kel-F COPV design would have less graphite fibre so lower mass.

RobertDyck · 2004-11-25 02:29:44

The ERV is my strongest concern with Mars Direct. I said the ERV is too small. The Mars Direct hab uses rotation for artificial gravity on the way to Mars. Robert Zubrin argued that zero-G would weaken astronauts too much. However, Shannon Lucent spent 6 months on Mir and walked off the Shuttle. She was able to do that due to exercise machines in Mir. I won't say artificial gravity is bad, but I'm not convinced it's an absolute necessity. However, the ERV didn't have either artificial gravity or sufficient room for zero-G exercise machines. Human health does require one or the other, an ERV with neither just isn't good enough.

As for the "suck it up soldier" attitude, I have noticed many psychologists claim people need a very large community. It seems they think a space station in Earth orbit requires a minimum of 100 people and a coffee shop with latte and cappuccino. Obviously this is wrong. However, I also argue that for psychology astronauts on Mars must be permitted frequent EVAs. NASA appears to be planning for 2-3 EVAs per week and only half the crew. I claim you must permit every astronaut to go outside every sol for the entire surface stay. That means designing suits to minimize suit consumables; not restricting the number of EVAs.

Ps. One person who knows Robert Zubrin told me he doesn't like being called Bob; he prefers Robert.

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Re: A "Quick & Dirty" Manned Mars Mission - How Would We Do It?

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