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#26 2004-11-25 07:23:34

Trebuchet
Banned
From: Florida
Registered: 2004-04-26
Posts: 419

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

Instead of worrying about how to make things smaller, how about making things much, much lighter? The following questions come to mind (feel free to add more):

1) How light in construction can you go, by using a virtually all-inflatable "Planetary Transfer Vehicle"?

2) How strong a magnetic field do you have to have around the craft to give it the same protection that solid, heavy shielding would give? Is the power requirement low enough to be met with solar panels?

3) Instead of using an ERV going directly from Mars to Earth, why not send the Mars surface hab seperately, and use the same (large) vehicle for both trips? This requires three launches, but still...

4) Because mass is expensive, but people need companionship for psycological reasons, why not send two crewmembers and *two lightweight pets*? People bond with pet animals as well, and they will use much less room, food, and water.

5) Mars Direct had lots of rovers and such. For a first "quick-and-dirty" mission, how about just sending one unpressurized rover to save a lot of weight? If it has a sortie range of 50km, that's still nearly 8000 square kilometers that it will cover.

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#27 2004-11-26 10:15:25

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

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

This K-Fel stuff is not magical, it is a polymer too, and if LOX will attack the epoxy of carbon composits, then I worry that it would attack K-Fel too. Its not just about permiability, its about reactivity.

As far the psych. community wanting much bigger crews and volumes, yeah that is probobly too much, but simply ignoring the concern because we don't know is irresponsable... lack of knowledge of the risks is not an excuse to ignore them.

Frequent EVAs are nice, but in the months coming and going between planets, that won't exactly be an option, and that is the time I am most worried about. Astronauts crammed in a relativly small space, probobly no gravity, few windows, no real-time communication, for 20-30 weeks solid.

Cutting the requirements back to only sending a crew of two people is pretty silly, they won't be able to get anything worthwhile done. Even four people will only get limited amounts of stuff done, and six with future provision for eight ought to be the minimum.

I want to reiterate that the AREA that a rover can cover is completly irrelivent, range is everything, we have to be able to visit as many geologic features of interest as possible in the ~500 day stay, which obviously calls for a vehicle with more range then 50km. Plus, if the ship the astronauts land in isn't the same one they take off or return to Earth in, then they should have a long range pressurized rover in the event the lander misses the landing site.


[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]

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#28 2004-11-26 11:31:15

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 7,877
Website

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

First it's called "Kel-F" not "K-Fel". Second I said LOX is reactive with graphite fibre, not epoxy. Yes, it is about reactivity. There are certain things each compound will react with; Kel-F like all fluoropolymers will not react with oxygen.

I agree; 4 astronauts are optimal for Mars. One or two of them should be cross-trained as paramedics rather than bringing a dedicated medical doctor.

At the 2003 Mars Society convention, Robert Zubrin told me he and Frank designed an inflatable tent trailer for Mars that could be towed behind an unpressurized rover. He was concerned that the analog rovers being developed by Mars Society chapters are far too big. It was supposed to transport astronauts to the ERV in case the Hab landed too far, not be a mobile laboratory.

Mars Society conventions are an excellent opportunity to talk to people like Robert Zubrin. You should go.

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#29 2004-11-26 12:17:36

BWhite
Member
From: Chicago, Illinois
Registered: 2004-06-16
Posts: 2,635

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

For the record, my two fictional Jesuits are not going to Mars for efficient science. Its merely an extreme flags and footprints mission with the objective of maximum publicity.

But if no tax dollars are spent, its a free world, right? And who should complain?


Give someone a sufficient [b][i]why[/i][/b] and they can endure just about any [b][i]how[/i][/b]

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#30 2004-11-26 13:07:29

C M Edwards
Member
From: Lake Charles LA USA
Registered: 2002-04-29
Posts: 1,012

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

The only way to really get a "quick and dirty" Mars mission is to neglect the ERV.  Not a one way trip, but one in which their ride home is not there when the astronauts arrive.  All the extra R&D budget, launch mass allowance, etc. that would have gone into having the ERV on Mars, tanked up and ready to go half a year before the crew arrives, can then go toward the crew module and supply caches.

Caches of supplies are simpler to launch than an Earth Return Vehicle.  Mining and construction equipment is simpler to launch than an Earth Return Vehicle.  Additional housing is simpler to launch than an Earth Return Vehicle.  Almost anything is simpler to launch than an Earth Return Vehicle.  Safer, too, I'll bet. 

If the crew wants an ERV, send them a bunch of little payloads to build their own rather than send it all together from Earth as one great big rocket.


"We go big, or we don't go."  - GCNRevenger

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#31 2004-11-26 13:30:10

John Creighton
Member
From: Nova Scotia, Canada
Registered: 2001-09-04
Posts: 2,401
Website

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

The only way to really get a "quick and dirty" Mars mission is to neglect the ERV.  Not a one way trip, but one in which their ride home is not there when the astronauts arrive.  All the extra R&D budget, launch mass allowance, etc. that would have gone into having the ERV on Mars, tanked up and ready to go half a year before the crew arrives, can then go toward the crew module and supply caches.

Caches of supplies are simpler to launch than an Earth Return Vehicle.  Mining and construction equipment is simpler to launch than an Earth Return Vehicle.  Additional housing is simpler to launch than an Earth Return Vehicle.  Almost anything is simpler to launch than an Earth Return Vehicle.  Safer, too, I'll bet. 

If the crew wants an ERV, send them a bunch of little payloads to build their own rather than send it all together from Earth as one great big rocket.

--------------
NASA is still blinking in surprise, trying to figure out why people love the rovers yet care less about the construction of the International Space Station than a new interchange outside Cleveland. It is only now sinking in that one is exploration and the other is, well, construction.

Imagine all the science and engineering that could be done. Who would sign up? Could you trust them not to sabotage the mission. Would they be skilled enough to get useful science or construction done?


Dig into the [url=http://child-civilization.blogspot.com/2006/12/political-grab-bag.html]political grab bag[/url] at [url=http://child-civilization.blogspot.com/]Child Civilization[/url]

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#32 2004-11-26 14:15:54

BWhite
Member
From: Chicago, Illinois
Registered: 2004-06-16
Posts: 2,635

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

Caches of supplies are simpler to launch than an Earth Return Vehicle.  Mining and construction equipment is simpler to launch than an Earth Return Vehicle.  Additional housing is simpler to launch than an Earth Return Vehicle.  Almost anything is simpler to launch than an Earth Return Vehicle.  Safer, too, I'll bet.

Exactly!

If someone went one way, use a freakin' Soyuz DM to land. With a bigger parachute, of course.

big_smile


Give someone a sufficient [b][i]why[/i][/b] and they can endure just about any [b][i]how[/i][/b]

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#33 2004-11-26 19:42:50

Ian Flint
Member
From: Colorado
Registered: 2003-09-24
Posts: 437

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

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.

What if you just launch/assemble your ITV in LEO, then when it is ready to go ---
1.  Launch a Centaur and dock with the ITV,
2.  Do a perigee kick to put the ITV in an elliptical orbit,
3.  Release the spent Centaur stage,
4.  Rinse, and repeat!

Keep doing these perigee kicks until TMI is achieved.  This method eliminates all the problems you mentioned.

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#34 2004-11-26 21:45:41

Austin Stanley
Member
From: Texarkana, TX
Registered: 2002-03-18
Posts: 519
Website

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

I imagnine a rendivous with a spacecraft in a high eliptical orbit would be fairly difficult.  It would be moving considerably faster than any craft that would want to dock with it.


He who refuses to do arithmetic is doomed to talk nonsense.

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#35 2004-11-27 15:39:58

RobS
Banned
From: South Bend, IN
Registered: 2002-01-15
Posts: 1,701
Website

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

A spacecraft wishing to dock to a vehicle in an elliptical orbit must first enter a near-identical elliptical orbit and approach slowly. There are no truly circular orbits. All dockings already occur in elliptical orbits, they just aren't very elliptical.

        -- RobS

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