Author Topic: Exploration Roadmap Working Group (ERWG) Data Collection, NASA's Inputs  (Read 11690 times)

Online rdale

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     This slide presentation reviews four areas for further space exploration: (1) Human Exploration of Mars Design Reference Architecture (DRA) 5.0, (2) Robotic Precursors targeting Near Earth Objects (NEO) for Human Exploration, (3) Notional Human Exploration of Near Earth Objects and (4) Low Earth Orbit (LEO) Refueling to Augment Human Exploration. The first presentation reviews the goals and objectives of the Mars DRA, presents a possible mission profile, innovation requirements for the mission and key risks and challenges for human exploration of Mars. The second presentation reviews the objective and goals of the robotic precursors to the NEO and the mission profile of such robotic exploration. The third presentation reviews the mission scenario of human exploration of NEO, the objectives and goals, the mission operational drivers, the key technology needs and a mission profile. The fourth and last presentation reviews the examples of possible refueling in low earth orbit prior to lunar orbit insertion, to allow for larger delivered payloads for a lunar mission.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20100015641_2010012841.pdf

Offline grdja

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Well, they still really really like to put Ares V as best for everything. And they still really really don't like fuel depots. But I'm waiting for people with far better understanding of issues than me to give their views.

Offline dks13827

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Well, they still really really like to put Ares V as best for everything. And they still really really don't like fuel depots. But I'm waiting for people with far better understanding of issues than me to give their views.
Simplicity is good, the whole rationale for POR.  Depots would require much additional dev work.  Not saying to ignore it.

Offline stealthyplains

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if it's so simple why did costs balloon out of sight

Offline jongoff

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Reminds me of the joke about how a "shortcut" is often the longest possible route between any two points.

Offline grdja

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Interesting, I genereally noticed a lot of people here and round the net have a similar mindset.

Create a huge HHLV that dwarfs Saturn V, no problem.
Use docking on a mission, way too complicated.
Fuel depots, ISRU, thats crazy science fiction talk, now where was my 150 ton to LEO stick...

Offline jimgagnon

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Interesting, I genereally noticed a lot of people here and round the net have a similar mindset.

Create a huge HHLV that dwarfs Saturn V, no problem.
Use docking on a mission, way too complicated.
Fuel depots, ISRU, thats crazy science fiction talk, now where was my 150 ton to LEO stick...

These slides looks like someone was told to take the Constellation architecture, shove in depots, and see where it goes. Hence the giggle factor. They allude to this in one slide where they state "Refueling not easy to retrofit into an existing approach — better to optimize the architecture around refueling by designing it in from the start, even if not initially used."

At least they're thinking depots now. Even shoe-horning it in as they did it had immediate benefits.

Offline dks13827

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if it's so simple why did costs balloon out of sight
I dont know.   seems to happen with fighters, rocket engines, space craft,, maybe even airliners.. these days.   it is not good, to say the least.  i dont doubt that rocket guys have attempted for  50 years to lower the cost per pound of payload.    i think one clue that i saw is that the shuttle main engines, if it was a new design, are not safe enough to use as is.  not sure that is such a great spec to lay on them...  given that they have not failed.   that's pretty good.   great, actually.
Apollo pretty much had a blank check, of course, so much was new, that was the deal.  Unique.   the Shuttle guys had to lie a lot to get the project approved then they got more money to finish it.  After the accidents they got more money to correct issues of course.
« Last Edit: 05/07/2010 06:17 pm by dks13827 »

Offline Jim

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if it's so simple why did costs balloon out of sight

Gov't program run by MSFC

Online Chris Bergin

Thread back on track and let's keep this thread productive. There's way too much smug baiting going on from one particular set of people. That's a fast track to losing posting privilages.
« Last Edit: 05/07/2010 09:38 pm by Chris Bergin »
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Offline KelvinZero

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I would like to hear some discussion of about what they are saying fuel depots and atlas-or-delta could achieve in the way of lunar missions. It seemed quite substantial to me, but I might be missing important details.

When they say 4-6 tons can be landed instead of 1-2 tons without depots, does that mean of cargo? That sounds like quite a lot. I mean you could surely land a couple of people with abort/ascent capability with that mass. Plenty if you already have infrastructure in place.

Offline kraisee

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Not sure if you're talking about a crewed landing, but if you are I doubt you can make any lunar lander which will be significantly more efficient than the Apollo LM was.

The completely dry Ascent Stage of the LM alone massed 2.2 mT.   With propellant it was 4.5 mT.

The dry Descent Stage was another 2.0 mT.   With propellant it was over 10.1 mT.

Minimum landed mass on the lunar surface was around 7.0 mT and that only enabled two people to land, perform a few hours of EVA, and stay for a maximum of 3 days.   Improving on that, even a little, is not going to be easy.

Ross.
« Last Edit: 05/08/2010 08:37 am by kraisee »
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Offline kkattula

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Not sure if you're talking about a crewed landing, but if you are I doubt you can make any lunar lander which will be significantly more efficient than the Apollo LM was.

The completely dry Ascent Stage of the LM alone massed 2.2 mT.   With propellant it was 4.5 mT.

The dry Descent Stage was another 2.0 mT.   With propellant it was over 10.1 mT.

Minimum landed mass on the lunar surface was around 7.0 mT and that only enabled two people to land, perform a few hours of EVA, and stay for a maximum of 3 days.   Improving on that, even a little, is not going to be easy.

Ross.

No pressure hull on the Ascent Stage? Crew ride in suits. EVA to the CEV in lunar orbit.

Offline madscientist197

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I don't think anyone in their right mind would want to make a lander as mass-efficient as the LEM again. The huge amount of extra costs introduced due to mass optimisation boggles the mind. There's nothing wrong with using better propellent mixtures, but structural optimisation can easily be taken too far.
John

Offline DGH

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I would like to hear some discussion of about what they are saying fuel depots and atlas-or-delta could achieve in the way of lunar missions. It seemed quite substantial to me, but I might be missing important details.

When they say 4-6 tons can be landed instead of 1-2 tons without depots, does that mean of cargo? That sounds like quite a lot. I mean you could surely land a couple of people with abort/ascent capability with that mass. Plenty if you already have infrastructure in place.

The numbers given are for an Atlas 551 not a Delta IV heavy.

The numbers for a Delta IV Heavy would be about 22 mt to TLI and 11 mt to the surface with refueling in LEO or 6-8 mt of cargo.
If you add refueling in LLO it would go to 17 tons to the surface.

ACES would kick this up to 34 mt to TLI and 17 mt to the surface.
With refueling in LLO 27 mt to the surface.

Even with out refueling the Delta IV Heavy could deliver about 5 mt to the surface which should break 2.5 mt of cargo more then a progress delivers to the station.


Offline KelvinZero

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Not sure if you're talking about a crewed landing, but if you are I doubt you can make any lunar lander which will be significantly more efficient than the Apollo LM was.

The completely dry Ascent Stage of the LM alone massed 2.2 mT.   With propellant it was 4.5 mT.

The dry Descent Stage was another 2.0 mT.   With propellant it was over 10.1 mT.

Minimum landed mass on the lunar surface was around 7.0 mT and that only enabled two people to land, perform a few hours of EVA, and stay for a maximum of 3 days.   Improving on that, even a little, is not going to be easy.

Ross.

I guess I was imagining you could save some weight because the LEM also had to be a base of operations on the surface, and it landed rovers and returned moon rocks etc.

A risk I saw with constellation is that the the cost might cause it to be dumped after a few missions, like apollo. Missions based on delta/atlas sized rockets might be much more sustainable because we will always have reasons for such sized rockets even without HSF?

I would imagine such an approach starting with landing really robust teleoperated rovers and really exploring the moon over a couple of years, including of course these polar craters. Satellites would be set up to allow teleoperation in these craters and on the far side also.

At some point we will have our ideal location for a human base: somewhere sheltered from cosmic and solar radiation and near ice. Then we start sending down inflatable modules, unmanned. Ideally these can be set up on the surface robotically. Also backup ascent vehicles could be sent.

Finally we send down people with the absolute minimum. This probably should still include the ability to abort to orbit. They would be much safer than the original Apollo astronauts because so long as they make it to the surface safely, there would be multiple rovers to get resources to them, and enough backups for them to survive until another mission could be launched.

The crew would also have a lot to do. They would have a whole set of missions laid out in advance that were beyond the abilities of the robotic rovers, and they would probably pay for themselves just through their ability to examine and repair the rovers anyway.

This sort of mission puts the emphasis on actually doing things on the moon, and doing them sustainably, rather than on big rockets, or on getting boot prints there for the sake of it.

Offline HappyMartian

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KelvinZero noted, "I would imagine such an approach starting with landing really robust teleoperated rovers and really exploring the moon over a couple of years, including of course these polar craters. Satellites would be set up to allow teleoperation in these craters and on the far side also."

Yes. And such teleoperated robots could allow for some useful contributions from our ISS Partners and also China and India. Congress should support such an option. Robots and international cooperation will also play increasingly important roles in the world's economic growth and ISS maintenance. Teleoperated robots on the Moon should be a 'salable product' to many governments around the world.

Budgets for American government projects are going to be tight for the forseeable future. Taking care of an aging population and reducing the national debt won't be easy. The teleoperation of robotic Lunar explorers should be affordable and part of any doable "Roadmap." The lunar robotic explorers will economically provide us with the needed information to evaluate useful locations for future outposts and colonies.

It may seem to be off topic, but money from the US Federal Government is an issue for almost every American space exploration proposal. There is an interesting article, "Secretary Gates to Slash Pentagon Budget in Search of $10 Billion in Savings" at: 

http://www.foxnews.com/politics/2010/05/08/secretary-gates-steps-campaign-change-way-military-does-business/

The article notes, "Gates said he had recently come to the conclusion about the urgent need for big cuts in light of the recession and the likelihood that Congress no longer will give the Pentagon the sizable budget increases it has enjoyed since the attacks of Sept. 11, 2001."

And, "'The gusher has been turned off and will stay off for a good period of time,' he said."

And, "In earlier remarks to reporters, Gates said it was clear that defense budgets will be tight 'for as far into the future as anyone can see.'"


The Defense Department isn't NASA, but a long-term fiscal problem with America's national budget plagues every part of our government. The budget problem is the main reason that planning to mostly make do with what we currently have to maintain the ISS and explore the Moon is the most sensible policy for Congress to provide funds for.

Getting some politically hyped expensive 'game changers' going might not really change the game at all. Maintaining the ISS National Laboratory by keeping the extremely useful Space Shuttles flying until we have something that can equal or exceed their abilities seems more logical than maybe someday building a rocket designed or chosen in some odd 'White House' closet.

America has successfully done mobile Martian robots. America can also build and land on the Moon teleoperated mobile Lunar robots that are capable of long-term exploration missions. In a time of economic difficulty, Congress should mainly try to hold on to or evolve heritage systems that work. Congress shouldn't gamble the ISS and Beyond Earth Orbit exploration on the evanescent words of a small group of speech writers that are employed by silver-tongued politicians.

Cheers!

« Last Edit: 05/09/2010 12:16 pm by HappyMartian »
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Offline Robotbeat

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One thing that I really hope is integrated into every mission architecture is an "abort to haven" capability, not just an "abort to Earth" one. Because on Mars, it's going to be months, or a year, until you get back to Earth, no matter what happens.

I agree with the minimal landers idea... permanent infrastructure is landed, like habs or rovers (could be used as makeshift pressure vessels... equipment designed to last decades), ahead of time. If there's a problem, abort-to-haven. For a Moon mission, that means that you don't spend any time on the lander except coming to or going from the Moon to LLO/EML1/2 (what are the phasing requirements for each?) where there's a spacecraft of some sort either capable of bringing them directly to Earth or capable of sustaining them for plenty long enough for a rescue mission or the next mission. And, any equipment placed on the Moon for humans is designed for long-term, even unforeseen, use. Long shelf-lives on everything.

Same thing for Mars. The MTV should be capable of sustaining them for the whole time there, if something bad happens to the lander (pre-placed in Martian orbit) between crew leaving Earth and arriving at Mars. For Conjunction-class missions, the hab must be capable of sustaining the crew for over a year. Make it capable of sustaining them even longer until emergency supplies could arrive in case of a problem with the lander (or MTV) after landing on Mars. Two havens, in that case.

Also, an exploration mission architecture for months-long missions should be flexible enough to give the astronauts something to do if stranded in Mars orbit for months (like a small excursion to Phobos or Deimos in the Orion).

Leave behind infrastructure every trip that could possibly be used by future crews (one reason I support Advanced RTGs for surface power that could supply power for decades, instead of fission-based surface power which typically doesn't last as long... or at least, use Advanced RTGs as backup). Highly mobile pressurized rovers could enable traveling thousands of miles, as well...

BTW, any word on progress on Constellation's Lunar Electric Rover???
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Offline Ben the Space Brit

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I agree with the minimal landers idea... permanent infrastructure is landed, like habs or rovers (could be used as makeshift pressure vessels... equipment designed to last decades), ahead of time.

Personally, I feel that this is a later-phase element.  You don't want to pay for permanent infrastructure until you know where you want to put it.  So a degree of 'excursion'-style survey will be required at once.  One way to square this circle is to have the lander able to act as a basic staging area and make it resupplyable.  So, you can run longer missions by pre-emplacing extra consumables by robotic cargo lander.

Phase 1 - Robotic precursors;
Phase 2 - Short-duration human survey;
Phase 3 - Long-duration human survey (say just one hab module, operated for many months by multiple crews);
Phase 4 - Permanent outpost.

Of course, Phase 2 is only practical for lunar missions.  The transit times for flights to Mars mean that a jump from Phase 1 to 3 is the best utilisation of effort.

On this subject, I would be very interested in people's views of commercial lunar resupply.  It strikes me as you only need a cargo lander to go one way - to the surface - It would be somewhat easier to build a cargo lander to put multi-tonne supply shipments within range of a lunar surface laboratory using 50t IMLEO commercial launchers (the EELV/ACES and Falcon-9/Raptor).  It would certainly make it easier to deliver bulk supplies like LiHO canisters, LOX tanks, water and concentrated foodstuffs if you could divide it up over multiple providers rather than have to focus everything onto a small number of launches where one failure could lead to having to abandon the outpost.
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Offline Robotbeat

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I agree with the minimal landers idea... permanent infrastructure is landed, like habs or rovers (could be used as makeshift pressure vessels... equipment designed to last decades), ahead of time.

Personally, I feel that this is a later-phase element.  You don't want to pay for permanent infrastructure until you know where you want to put it.  So a degree of 'excursion'-style survey will be required at once.  ...
I agree. What I meant was that it would be designed for long-term use, but would only need to be qualified for shorter lengths of time...

Think of it this way: A battery-only-powered rover has a quite limited life set by its battery supply, but a solar-powered rover could work for years, even if only originally qualified for a few months... You don't necessarily expect it to last longer, but you design it in such a way that it has a chance of working far, far longer.

In the case of pressurized rovers, allow them to be remotely pilotable so that after the manned mission is over, you can still drive them around and see how long the bearings, etc, work in that environment. This gives you potentially the opportunity to see how long something will work and what breaks down first so that you can be enlightened to what would really be needed to make it "permanent" infrastructure.

Another example would be designing an cooled infrared space telescope. One design would use just a reservoir of liquid helium or solid hydrogen, while another design would use a cryocooler. One has a definite lifetime, the other has a qualified life, but you can't necessarily rule out that it'd last many, many times longer. I would encourage a design philosophy that would emphasize latter whenever practical. Test long-term solutions even if your mission is short-term.

This is one reason I am glad that NASA is considering electric propulsion demonstrators... since the Isp is so high, even just 10% extra propellant can buy you a lot of delta-v. Also one reason electrodeless electric thrusters should be investigated, since they could last a very long time.
Quote
On this subject, I would be very interested in people's views of commercial lunar resupply.  It strikes me as you only need a cargo lander to go one way - to the surface - It would be somewhat easier to build a cargo lander to put multi-tonne supply shipments within range of a lunar surface laboratory using 50t IMLEO commercial launchers (the EELV/ACES and Falcon-9/Raptor).  It would certainly make it easier to deliver bulk supplies like LiHO canisters, LOX tanks, water and concentrated foodstuffs if you could divide it up over multiple providers rather than have to focus everything onto a small number of launches where one failure could lead to having to abandon the outpost.
I like that idea.
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