New Mars Forums

Official discussion forum of The Mars Society and MarsNews.com

You are not logged in.

Announcement

Announcement: This forum is accepting new registrations by emailing newmarsmember * gmail.com become a registered member. Read the Recruiting expertise for NewMars Forum topic in Meta New Mars for other information for this process.

#76 2006-12-14 14:34:52

cIclops
Member
Registered: 2005-06-16
Posts: 3,230

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

There is justification for staying at the Moon and it is not just for scientific reasons. It is reasons that the public and politicians alike can understand and in that understanding we have not only there acceptance but there support. The ISS is an incredibly expensive white elephant and can only be improved by expensive deliveries from Earth. This is not the case with the Moon and unless we find the means to decrease costs while increasing our capacity for action in space then we will not get to go to Mars anywhere in the near term like the 21st century.

So what exactly are these reasons? The Lunar Outpost will cost MUCH more than ISS to operate, the cost per kg on the Moon is 5 times that for LEO. ISRU may work eventually and be able to provide oxygen, everything else will have to be brought from Earth at about $50,000 kg. Sure one day, far in the future, the base will be as accessible and extensive as the South Pole base is now .... one day.


[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]

Offline

#77 2006-12-14 15:25:48

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

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

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.

In any event, I take your incredulus notion as to how much a Mars mission "should" weigh as proof that you've swallowed Zubrin's dreck hook/line/sinker: the crazy 240MT "price tag" that Bob put on MarsDirect just isn't a number in the realm of reason, its not a valid yard stick to compare to other plans. The question isn't "why is DRM-IIIb so heavy," the question is why is MarsDirect so light?

Why shouldn't a Mars mission go with six people? After all that trouble, expense, and flight time you want to restrict exploration to only two or three actual explorers every few years? And why shouldn't a heavy-duty rover be part of the baseline science package? We should be restricted to short-range rovers for the whole 500 day stay? (Bob's figure for a pressurized rover is a joke BTW) And why shouldn't we demand plenty of payload for a future heavy-duty drill, megawatt-class nuclear plant, and other equipment to seriously look for water/life or build a base?

MarsDirect or anything smaller doesn't give you any of these; life is not going to be convienantly at the surface, with its dessicating thin atmosphere, bleaching dirt, and harsh UV radiation. We're going to have to drill for it, and a drill is going to weigh a few tonnes. If we are going to build a base, we are going to need a heavy-duty nuclear plant, and thats going to weigh a few tens of tonnes. So will a heavy ISRU plant, etc etc etc. You can't cram any of these things in with MarsDirect.

And so if we can't bring these things, if the rockets just aren't big enough, then we've cheated the taxpayers and the people of this planet by paying for a mission thats not quite as expensive but accomplishes virtually nothing. To get down to it, we will have wasted all the money, years, and political will for scraps when we could have spent a bit more but achieve something.


[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]

Offline

#78 2006-12-14 15:31:04

cIclops
Member
Registered: 2005-06-16
Posts: 3,230

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

And all this assumes that the problem of landing heavy packages on Mars can be solved. Right now nobody knows how to put more than a few tons on the surface. Ballutes may be the answer.


[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]

Offline

#79 2006-12-14 16:15:31

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

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

And all this assumes that the problem of landing heavy packages on Mars can be solved. Right now nobody knows how to put more than a few tons on the surface. Ballutes may be the answer.

If we can't solve that, then nobody is going to Mars, ever. Why can't we do it the same way as Apollo? Powered landing from space to the surface, perhaps with parachutes thrown in to cut the fuel bill a little.

The old Viking probes seemed to have worked just fine too.


[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]

Offline

#80 2006-12-14 16:35:58

Grypd
Member
From: Scotland, Europe
Registered: 2004-06-07
Posts: 1,879

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

There is justification for staying at the Moon and it is not just for scientific reasons. It is reasons that the public and politicians alike can understand and in that understanding we have not only there acceptance but there support. The ISS is an incredibly expensive white elephant and can only be improved by expensive deliveries from Earth. This is not the case with the Moon and unless we find the means to decrease costs while increasing our capacity for action in space then we will not get to go to Mars anywhere in the near term like the 21st century.

So what exactly are these reasons? The Lunar Outpost will cost MUCH more than ISS to operate, the cost per kg on the Moon is 5 times that for LEO. ISRU may work eventually and be able to provide oxygen, everything else will have to be brought from Earth at about $50,000 kg. Sure one day, far in the future, the base will be as accessible and extensive as the South Pole base is now .... one day.

One day, yes but the idea is that we develop technologies to ensure that access and return from the Moon not only improves but gets cheaper. And though access costs will be more expensive the actual running costs will be a lot less. And there is the fact that we can actually make things from the enviroment not just rocket fuel. The principle is that we develop the Moon using what we find and take as little from Earth as possible. The currency of space is energy and it is something the Moon has in abundance. We have developed an automated process to garner solar cells purely from lunar materials and each cell increases our capacity.

Do we need people to do it NO. But for the science part we do. The Moon is close enough that we can use telerobotics to keep increasing our capacity for action on the Moon. Each time we are able to build, gather a resource or just plain mineral search we increase our future in space and probabily improve life here on Earth. Another advantage is that we can for the first time return resources which can pay there way even with the high costs of rockets.

This will drive the research and development of reusable lunar landers and also reusable to LEO vehicles. This will reduce costs to operate in space and will spur space development. Further pushing the frontier and reducing costs.


Chan eil mi aig a bheil ùidh ann an gleidheadh an status quo; Tha mi airson cur às e.

Offline

#81 2006-12-14 16:37:54

RedStreak
Banned
From: Illinois
Registered: 2006-05-12
Posts: 541

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

I don't suppose there's any thoughts to aerobraking?  With or without ISRU that would reduce propellant needs, and off-hand I see two ways we can utilize it at Mars.

1) Aerocapture - Full Blown MOI dive into the atmosphere.  This is the riskier of the two options but I think the bigger part of the risk is that it hasn't been done before, not even with probes unless you count landers.  If safety boards shoot this option to hell then there's still...

2) Aerobraking - to reduce risk the craft could brake with propellants into a high orbit.  After that, the transit vehicle (whether an Orion or otherwise) and lander seperate with the lander using its heat shield to skim day by day into the atmosphere.  Considering we have a heat shield on the shuttle orbiter that is reuseable this isn't inconceivable - naturally update the concept a bit and with something less brittle but, unlike the orbiter, once the entry into the Martian stratosphere is done it'd be ejected.

I think they need to consider this, and if no one wants ISRU or mega-mass spacecraft (the later killing off both nuclear and solar electric drives) this is about only option.

Offline

#82 2006-12-14 16:47:15

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

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

Oh, full-on atmospheric orbital capture is assumed in MarsDirect and DRM-III to hold down mass. This is one of those "must work" technologies, both development and actual use.


[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]

Offline

#83 2006-12-14 16:50:59

Dayton Kitchens
Member
From: Norphlet, Arkansas
Registered: 2005-12-13
Posts: 183

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

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?

Offline

#84 2006-12-14 17:03:36

Grypd
Member
From: Scotland, Europe
Registered: 2004-06-07
Posts: 1,879

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

The NIMF technology fueled by methane fuels maybe.


Chan eil mi aig a bheil ùidh ann an gleidheadh an status quo; Tha mi airson cur às e.

Offline

#85 2006-12-14 20:38:06

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

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

Thats pretty close. The point being that the same rockets used to send the first crews, who do initial exploration and find a site to put the base, can also be used to send the base components without any major changes. If the cost is too high and time required to build this base is too long, then that substantially decreases the chance it will be built.

The other point also stands though, that while you can probably put three people on Mars with something not much bigger than MarsDirect, nothing short of a DRM-III scale mission (and preferably a little bigger) actually provides the payload capacity to do real science either.

For both these reasons, its critical that we go big, or we don't go. I'm no publiusr, but no MarsDirect-class missions, they are just too small and too far between something big enough. As a practical note for any mission, we must absolutely build big enough so that if weight creep strikes we won't be knee-capped or derailed by it (Shuttle, X-33/VentureStar, etc). MarsDirect throws this common sense principle right out the proverbial airlock.

The reuseable landers won't do much good until we actually have a base too, the whole point of having them is to use 100% Martian rocket fuel to save from having to launch/send expendable vehicle and their fuel from Earth for the purpose of going from Mars to LMO and back.

With aerobraking, even the Ares-I (with an upgraded upper stage or a third stage) could send ~10MT cargo modules to Mars orbit where the RMAV would ferry them to the surface. So could the Delta-IV Heavy or the hypothetical Falcon-IX. Enough mass for all the supplies & gear a 2-year mission could want (especially since water is provided), a small pressurized building, or a heavy rover.

Then we will be on Mars, have all the elements needed for life, and have a means of transporting people or light cargo at a small fraction of what it used to cost. And thats about as good as NASA can do within its means, is to set up a Mars base and make it affordable to operate it. If people want to colonize, then they will have to pick up the flag from there.

Its going to take some time to make this base though, first of all we have to find water or ice somewhere, preferably someplace not too cold and near(ish) interesting sites to visit. When base building starts depends on how soon we find a suitable spot, and how quickly the components can be developed & built. This would be done with the money used to develop the Mars ships.

Then comes the lifting:

  • -Megawatt class nuclear plant
    -Heavy diggers/tractors and drill
    -Heavy ISRU plant/permafrost extractor
    -Reuseable "RMAV" (two pieces)
    -One load of miscellaneous equipment and spares

For a total of six cargo missions, preferably with one manned mission to accompany and assemble them. The RMAV would be afforded two flights in case it and ancillary hardware is too much to fit in one flight. This would take up two manned missions worth of Ares-V rockets & landers, which I think is reasonable.

A seventh heavy cargo launch might bring an inflatable HAB and hanger/workshop, with the two HABs (the one that found the site and the one used by the assembly crew) would be buried and mated for housing in the interim. Later on preferably a second backup RMAV would be sent.

The RMAV would be fairly big, capable of launching and retrieving a crew of eight or 10MT of payload from orbit, and probably strongly resemble the old DC-X, except powered by Methane. While it might be able to serve as a "Hopper," that wouldn't be its primary use, and it would be nice to have the second RMAV on hand to rescue the crew of the first if they were stranded away from the base.

The fuel tanks for all the old landers (all 12-14) would be used to store fuel or water produced by the heavy ISRU plant as kind of a tank farm too.

***NOTE: edited 10pm EST


[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]

Offline

#86 2006-12-14 21:40:38

RedStreak
Banned
From: Illinois
Registered: 2006-05-12
Posts: 541

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

Agreed on reusing fuel tanks and making a strong effort when we do go to Mars.

So large landers both manned and unmanned, establishing ISRU asap, aerobraking, and canabalizing spent surface stages are all solid ideas.

They ought to design the landers to be modular, and by that I mean the indivual lander components; so we can pull off a tank and then just wheel it over to wherever its needed - i.e. we drive our manned rover up to it, unscrew a few bolts, plop it on the trunk of the rover, and drive back to the base.  This'd be handy for either Luna or Mars if we really wanna utilize existing equiptment.  Screw reuseable landers if we can fully canabalize the old stuff!  smile

Offline

#87 2006-12-14 21:43:58

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

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

GCNRevenger, that sounds quite reasonable.

I might still allow for the use of "small" vehicles like Mars Direct, but in the end it must be conceded: the Mars Direct mission architecture is too small to accomplish anything of importance by itself.  Its only virtue would be as one element of a single, larger and cohesive mission archetecture.  Deployed as Zubrin envisions it - as the entirety of the mission, and just one other-directed mission in an only coincidentally related series - it's useless.

We go big, or we don't go.  Mars Direct hardware could help with that, but Mars Direct ultimately will not.


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

Offline

#88 2006-12-14 22:01:05

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

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

Agreed on reusing fuel tanks and making a strong effort when we do go to Mars.

So large landers both manned and unmanned, establishing ISRU asap, aerobraking, and canabalizing spent surface stages are all solid ideas.

They ought to design the landers to be modular, and by that I mean the indivual lander components; so we can pull off a tank and then just wheel it over to wherever its needed - i.e. we drive our manned rover up to it, unscrew a few bolts, plop it on the trunk of the rover, and drive back to the base.  This'd be handy for either Luna or Mars if we really wanna utilize existing equiptment.  Screw reuseable landers if we can fully canabalize the old stuff!  smile

NONONO! Non! Niet! Nein! RE-USEABLE. That way you can bring down as many crews or small cargoes or long-range suborbital trips as you want, and not just how many you have left over lander parts for. smile


[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]

Offline

#89 2006-12-14 22:57:04

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

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

To summarize:

  • -NASA learn how to make Ares-V without breaking the bank
    -130MT fully fueled "SuperEDS" stages are orbited on top of stock Ares-V
    -100MT+ Mars ships are launched on stock Ares-V with a ~30MT Centaur booster on the back; mated with the former and fly to Mars, orbital capture by aerobraking
    -Three versions of Mars ship are built, HAB, cargo, and ERV

    • -HAB carries 6-8 crew from LEO to Mars surface
      -Cargo carries the Mars Ascent Vehicle, small ISRU plant, rover for manned missions or heavy cargo for base construction
      -ERV parks in Mars orbit, MAV launches to it and the crew transfer for the trip to Earth
      -Each manned mission requires six Ares-V, three SuperEDS, the above three ships, plus one Ares-I/Orion

    -Initial missions search for life and suitable base sites, emphasis on water
    -Once site is confirmed, base elements are delivered in lieu of crew for one or two biannual launch opportunities

    • -heavy nuclear reactor
      -heavy diggers/tractors, permafrost drill
      -heavy ISRU plant
      -delivery of reuseable MAV(s) ("RMAV")
      -total of 10 Ares-V launches (minimum) or 14 (maximum) depending on the need for miscellaneous parts and size of RMAV (two vehicles?)
      will RMAV fit in one cargo flight?

    -With ISRU and RMAV in service...

    • -Light/medium cargo (10MT) now sent by 25MT class launch vehicle, radically reducing cost for consumeables, permits smaller-scale construction & science projects, and point of entry for AltSpace providers.
      -ERV design converted into a reuseable transit vehicle capable of aerobraking into Earth orbit and carries extended fuel tanks to help with TMI or to abort to Earth in an emergency (replacing Centaur booster?).
      -In LEO it will have its fuel tanks refueled by heavy lifter or commercial RLVs and be mated to a new SuperEDS launched by Ares-V. Crews exchange on Ares-I/Orion or commercial crew vehicle.
      -ERV then flies to Mars orbit and crews exchange via RMAV and flies back for the next rotation.

    -Combined with RMAVs being used as long-range suborbital "Hoppers," we get effective, efficient, and sustained presence on Mars for a price thats not unaffordable.


[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]

Offline

#90 2006-12-14 23:28:10

RedStreak
Banned
From: Illinois
Registered: 2006-05-12
Posts: 541

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

[NONONO! Non! Niet! Nein! RE-USEABLE. That way you can bring down as many crews or small cargoes or long-range suborbital trips as you want, and not just how many you have left over lander parts for. smile

To quote Grandpa Simpson consider this:

"...a little from collumn A and a little from collumn B."  tongue

Whatever we send that stays on the surface permenantly out to be canabalized.  A reuseable lander would pretty much be out of the loop so no worries.  The bottom stage of those cargo landers and even the framework should be taken apart on other hand.  You spend several million lofting up a pound of metal you OUGHT to make sure the taxpayers get their money's worth.

Offline

#91 2006-12-15 00:04:49

RedStreak
Banned
From: Illinois
Registered: 2006-05-12
Posts: 541

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

I think a reuseable RMAV would be tricky to sustain.  On airless Luna yes, a return shuttle is possible b/c there's a vaccum and, desite temp extremes, no atmosphere and no heatshields/shrouds.  On Mars its constant cold and whenever you venture to or from the surface you have to keep the atmosphere in mind.

We won't have a factory or facility on Mars for decades that'll be capable of manufacturing and repairing spacecraft, so if you're planing to refurnish this thing Earth is about the only place it could be taken otherwise you're talking about a vehicle with just a few trips in its lifetimes, certainly less than a dozen.

What did you have in mind for a RMAV?

Offline

#92 2006-12-15 01:53:24

cIclops
Member
Registered: 2005-06-16
Posts: 3,230

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

If we can't solve that, then nobody is going to Mars, ever. Why can't we do it the same way as Apollo? Powered landing from space to the surface, perhaps with parachutes thrown in to cut the fuel bill a little.

The old Viking probes seemed to have worked just fine too.

Because Mars has an atmosphere, landers can't use rockets to slow down without flying backwards through their plumes. Yes parachutes work well after hypersonic reentry but their payload is limited. Once the velocity is low enough, rockets can be used near the surface for final braking. Viking had a lander mass of only 600 kg.


[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]

Offline

#93 2006-12-15 06:45:44

cIclops
Member
Registered: 2005-06-16
Posts: 3,230

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

-Three versions of Mars ship are built, HAB, cargo, and ERV
-HAB carries 6-8 crew from LEO to Mars surface
-Cargo carries the Mars Ascent Vehicle, small ISRU plant, rover for manned missions or heavy cargo for base construction
-ERV parks in Mars orbit, MAV launches to it and the crew transfer for the trip to Earth

This is very risky. If the crew + HAB land too far from the MAV (ascender) they are doomed. Better to land the crew in a MSAM type vehicle (descender + ascender), if they can't reach the prepositioned HAB etc they can abort back to Mars orbit.

Just found this new AIAA ppt (2MB) showing how Ares V can be used for Mars missions. The TMI mass for a single Ares V is given as 45 mT, and 34 mT to Mars Orbit, and 22 mT to the surface.


[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]

Offline

#94 2006-12-15 07:23:34

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 29,433

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

Well here is the important piece in GCNRevenger's plan of a Megawatt class nuclear plant.
Race to the Moon for Nuclear Fuel

At the Fusion Technology Institute, Kulcinski's team has produced small-scale helium-3 fusion reactions in the basketball-sized fusion device. The reactor produced one milliwatt of power on a continuous basis.

While still theoretical, nuclear fusion is touted as a safer, more sustainable way to generate nuclear energy: Fusion plants produce much less radioactive waste, especially if powered by helium-3.


I think that the experts which say commercial-sized fusion reactors are at least 50 years away are long on there estimates.

Offline

#95 2006-12-15 07:30:37

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

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

I think a reuseable RMAV would be tricky to sustain.  On airless Luna yes, a return shuttle is possible b/c there's a vaccum and, desite temp extremes, no atmosphere and no heatshields/shrouds.  On Mars its constant cold and whenever you venture to or from the surface you have to keep the atmosphere in mind.

We won't have a factory or facility on Mars for decades that'll be capable of manufacturing and repairing spacecraft, so if you're planing to refurnish this thing Earth is about the only place it could be taken otherwise you're talking about a vehicle with just a few trips in its lifetimes, certainly less than a dozen.

What did you have in mind for a RMAV?

I think that you make out Mars reentry a scarier thing than it really is, the Martian atmosphere is quite thin and it isn't impractical to make a reuseable heat shield. We have all-metal heat shield tiles now that have even been tested on low-heating areas of the Shuttle shield, and the same material ought to do just fine on Mars. If not, or for the areas that might be heated more, plain old RCC panels would work too; the ones on the Shuttle's nose/wings are not refurbished between missions, only inspected, and are a fully reuseable shield too. These panels might be kept small enough so replacements could fit in a 10MT cargo flight if need be. As far as how many flights such a vehicle should be capable of, if you include suborbital "hops" then I think the RMAV ought to be capable of about two dozen flights.


[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]

Offline

#96 2006-12-15 07:33:25

cIclops
Member
Registered: 2005-06-16
Posts: 3,230

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

At the Fusion Technology Institute, Kulcinski's team has produced small-scale helium-3 fusion reactions in the basketball-sized fusion device. The reactor produced one milliwatt of power on a continuous basis.

It's curious that at the Fusion Technology Institute's website they don't even mention that they have made a massive breakthrough in producing continuous fusion power in a basket ball size device. Could this be utter nonsense?


[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]

Offline

#97 2006-12-15 07:45:01

Dayton Kitchens
Member
From: Norphlet, Arkansas
Registered: 2005-12-13
Posts: 183

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

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.

Offline

#98 2006-12-15 08:23:59

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

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

If we can't solve that, then nobody is going to Mars, ever. Why can't we do it the same way as Apollo? Powered landing from space to the surface, perhaps with parachutes thrown in to cut the fuel bill a little.

The old Viking probes seemed to have worked just fine too.

Because Mars has an atmosphere, landers can't use rockets to slow down without flying backwards through their plumes. Yes parachutes work well after hypersonic reentry but their payload is limited. Once the velocity is low enough, rockets can be used near the surface for final braking. Viking had a lander mass of only 600 kg.

With the Martian atmosphere so thin however, I bet you could add extendable "strakes" to increase drag when heating isn't too bad in lieu of parachutes:
f-15-16.jpg
Then when the speed is lower, it goes ahead performs the flip and fires the main engine again to land.

You also only "fly through your exhaust" when the exhaust is traveling much slower than you are, and since the air is so thin on Mars your exhaust won't decelerate near as much versus Earth. Hence you can burn your engine all you like in the upper reaches of the atmosphere since there is next to nothing to slow the exhaust down, just like the Moon. And when at low altitudes the exhaust velocity (3.7kms @ 379ec Isp) will be significantly greater than the RMAV's velocity and won't be a big worry either.


[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]

Offline

#99 2006-12-15 08:28:10

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

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

At the Fusion Technology Institute, Kulcinski's team has produced small-scale helium-3 fusion reactions in the basketball-sized fusion device. The reactor produced one milliwatt of power on a continuous basis.

It's curious that at the Fusion Technology Institute's website they don't even mention that they have made a massive breakthrough in producing continuous fusion power in a basket ball size device. Could this be utter nonsense?

Sure, its called a Farnsworth Fusor, we've had those for years. A kid even built one for a highschool science project competition. The catch is they can't make one that produces more power than it consumes, and it doesn't scale well.

I bet we could even build a large reactor that produced net positive energy. But just being net positive, like the pathetically small 1mW power output of their gadget, isn't good enough. You need large excesses of power, or its not worth fooling with.


[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]

Offline

#100 2006-12-15 09:47:56

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

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

-Three versions of Mars ship are built, HAB, cargo, and ERV
-HAB carries 6-8 crew from LEO to Mars surface
-Cargo carries the Mars Ascent Vehicle, small ISRU plant, rover for manned missions or heavy cargo for base construction
-ERV parks in Mars orbit, MAV launches to it and the crew transfer for the trip to Earth

This is very risky. If the crew + HAB land too far from the MAV (ascender) they are doomed. Better to land the crew in a MSAM type vehicle (descender + ascender), if they can't reach the prepositioned HAB etc they can abort back to Mars orbit.

Just found this new AIAA ppt (2MB) showing how Ares V can be used for Mars missions. The TMI mass for a single Ares V is given as 45 mT, and 34 mT to Mars Orbit, and 22 mT to the surface.

It is a risk, but I don't think that its a big one. If we can't learn to land with good accuracy, then Mars is out of our technological reach. We have ICBMs capable of accuracy within a few hundred feet, and thats without powered landing and a thick atmosphere. We can do this, and its worth the chance.


[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]

Offline

Board footer

Powered by FluxBB