Author Topic: ALTERNATIVE - NON SLS: Exploration Gateway Platform - Reusable Lunar Lander  (Read 55691 times)

Online Chris Bergin

http://www.nasaspaceflight.com/2011/12/exploration-gateway-platform-hosting-reusable-lunar-lander-proposed/

Associated baseline thread:
http://forum.nasaspaceflight.com/index.php?topic=27446.0

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Public resources used:
http://www.nasa.gov/pdf/604643main_2-Panel%202_Donahue_Final.pdf
http://spirit.as.utexas.edu/~fiso/telecon/Hatfield_8-10-11/

Main L2 Resource used:
http://forum.nasaspaceflight.com/index.php?topic=22048.0


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THIS THREAD is for a splinter discussion about this sort of architecture without use of the SLS.

Let's not overlap, so this is no SLS. The main thread is for SLS - given that's how the documentation was designed.

Offline Norm Hartnett

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Heh, I guess that it's not as much fun to talk to folks that agree with you.

It appears that the Gateway plan is actually launcher independent which is a plus in my book given history.

Assembly of the Gateway at the ISS is a plus in ISS utilization and a negative for impact on ongoing micro gravity research there.

Pathfinder mission from Gateway at ISS is a plus for testing capabilities such as fuel depot in LEO.

Moving Gateway from ISS to L1 is a plus as it will require new technologies that are required for future exploration.

Gateway at L1 is, without a doubt, the most important part of this plan. While Lunar exploration is nice and all, quantifying the problems of long term deep space habitation is far more important to any serious exploration of the solar system.
“You can’t take a traditional approach and expect anything but the traditional results, which has been broken budgets and not fielding any flight hardware.” Mike Gold - Apollo, STS, CxP; those that don't learn from history are condemned to repeat it: SLS.

Offline MATTBLAK

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I'm cutting-and-pasting the text from another post of mine which is exactly relevant to this thread, with a couple added sentences:

*If SLS gets cancelled - and I hope it doesn't but I'm pragmatic - then a 'dynamic duo' of enhanced Delta IV-H and Falcon Heavy should do a bunch of demonstration BEO missions (to a Gateway Station):

*Lunar flyby to then loiter at L-2 - gives Orion OR Dragon the chance to prove deep-space capability: thermal extremes, radiation survival, propulsion, life support, communications etc. A mission like this, especially coupled with the Tele-Operation of robot/probes on the Lunar surface (Farside and South Polar) shows the way to NEA and Phobos/Deimos missions. And they wouldn't really need a 'Hab Module' to do it - just a small crew and restrict it to 14-18 days.

*Propellant Depot technology demonstration missions - put a Node, inflatable Hab and/or Zvzeda-class module there, along with a basic, 200 metric ton (loaded) cryogenic demo stage. They could use this module to demo refueling of a pathfinder CPS stage that is then used to transfer the Orion/Dragon to Lunar orbit or L-1 to pick up sample-return probes from remote lunar sites. With a mission like that, you've proven most concepts necessary for a Martian Moon or deep-space asteroid mission. And all the while, extend the duration and equipment reliability tests with each mission. Most 'Flexible Path' technologies can be demonstrated first by making full use of Cislunar and Lagrange space.

*And in addition to 'Flexible Path' ideas, a re-usable Lunar Lander is exactly what is needed. Once at the Gateway Station, single-launch SLS missions to the Moon OR 2x/3x launch Falcon Heavy/Delta IV-H (upgraded) will give a lot of capability and flexibility.
« Last Edit: 12/03/2011 09:45 PM by MATTBLAK »
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Offline mmeijeri

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Gateway at L1 is, without a doubt, the most important part of this plan.

Heh, that's how I felt too initially, but I've since completely changed my mind. While trying to find money for it, I tried to get rid of the SDLV US. That required propellant transfer, which is what led me to hypergolics, which I had wanted to avoid initially! And then I learned of the potential of commercial propellant launches to slash launch prices by an order of magnitude, which could make substantial commercial manned spaceflight a reality soon.

Since then I've believed that establishing a large and fiercely competitive commercial propellant launch market was the most important thing. In the current proposal that would mean focusing on the lander, which I'd make fully hypergolic and which I would base on the Orion SM, avionics and perhaps life support systems. An unmanned precursor would be useful and that could fulfil early missions of opportunity to spend as much money on propellant as possible as early as possible.

So ironically, while my quest began with an attempt to find money for a gateway station because lunar missions could wait, it has since led me to believe a gateway station is one of the things we should postpone until later while the lander is actually the most crucial part! Interesting to see where you end up if you actually follow the evidence instead of sticking to an initial hunch or letting ulterior motives dictate your technical choices.
« Last Edit: 12/04/2011 09:42 AM by mmeijeri »
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Offline mmeijeri

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a 'dynamic duo' of enhanced Delta IV-H and Falcon Heavy should do a bunch of demonstration BEO missions (to a Gateway Station):

You don't even need the FH, although there would be nothing against using it if it were competitive with EELVs and wouldn't require dedicated funding.
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Offline Nathan

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Small reusable refuel able spacecraft are the way forward. This is a good start. No need for sls. Need reusable fuel tankers.
Given finite cash, if we want to go to Mars then we should go to Mars.

Offline MATTBLAK

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If you base the lander descent stage on the Orion SM - a not entirely silly idea - you would need to make the engine able to throttle. And I agree with Martin that with hypergolics, a commercial-based propellant supply chain could almost be done NOW! Technologically, there is nothing about hypergolic Propellant Depots that cannot be done right now, today. And the Isp of hypergolic engines staged from L-1 or L-2 would still get you to most places on the Moon, particularly if the best hypergolic engine and structural materials technology available are used.

And I used the Falcon Heavy idea because Elon is developing it on his own coin, not taxpayer dollars and with its superior capability to Delta IV or Atlas V, F-H would open up possibilities for larger, more capable spacecraft. If the Depots evolved from Hypergolic to Cryogenic or liquid methane/LOX technologies, suddenly missions to the Martian Moons or even the Martian surface itself start to look attractive with Falcon Heavy! And I mentioned an enhanced Delta IV-H only because that booster can be upgraded a fair way for relatively little money (compared to SLS) and leaving its existing launchpads largely alone.
« Last Edit: 12/05/2011 09:16 AM by MATTBLAK »
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Offline mmeijeri

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Small reusable refuel able spacecraft are the way forward. This is a good start. No need for sls. Need reusable fuel tankers.

Or if there is to be an SLS at all, it should either not have its own US, but use an existing EELV US instead, or use a new EELV compatible ACES and carry only crew, not landers, depots etc and above all no propellant as payload. This would not be nearly as good as getting NASA out of the launch business, but it could be (barely) acceptable from the point of view of opening up space.
« Last Edit: 12/03/2011 10:23 PM by mmeijeri »
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Offline mmeijeri

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If you go with a horizontal lander and a crasher stage you would not need to throttle deeply. You might need a pump-fed engine for the crasher, depending on its size, which could be a newly upgraded Aestus 2 or RS-72, a revived Viking or a Titan engine, or an existing Russian engine.
« Last Edit: 12/03/2011 09:56 PM by mmeijeri »
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Offline Nathan

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An atv could be the international module
Given finite cash, if we want to go to Mars then we should go to Mars.

Offline mmeijeri

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An atv could be the international module

ESA was interested in this sort of thing, but unfortunately they don't have any money either. There were plans for an EU manned space program, but right now I don't think anybody would dare suggest anything like that in light of the current financial crisis in Europe...
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Offline MATTBLAK

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An atv could be the international module

ESA was interested in this sort of thing, but unfortunately they don't have any money either. There were plans for an EU manned space program, but right now I don't think anybody would dare suggest anything like that in light of the current financial crisis in Europe...

All true, it's very sad. But even when Europe's and the world's economies were in better shape, not much was being spent on Space. If we can't look at better, more efficient (cheaper?) ways to do things right now, even more valuable momentum and skill sets will be lost. If we keep deferring the Future, we may never get to have a future.
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But other than this post and it's content, perhaps we better not digress too much, eh?
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Online oldAtlas_Eguy

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In this architecture, one of the most expensive part of the mission is getting to and from the Gateway from Earth. A surface mission requires 9MT of supplies & propellant plus the crasher stage. A larger fully reusable lander that does not require a crasher stage plus a depot would enable performing multiple surface missions for one crew mission from Earth. The multiple sets of surface missions and propellant supplies would be delivered to the Gateway earlier followed by the crew mission to the Gateway for a long duration several months long mission to do multiple surface exploration missions 4 to 6 or more with each lasting about 7 days. Meaning you could do about 3 times as many surface missions for the same cost.

Offline mmeijeri

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There isn't much wrong with using a crasher stage, but I wouldn't want to use a prefueled stage launched all the way to L1/L2 for it. If the crasher is refuelable too you've essentially lifted all size constraints from the lander. This was first pointed out to me by (get this) Chuck Longton. Isn't it ironic that the crasher stage was sized based on the payload of an SLS to L1/L2, which turns out to be a limiting factor? It illustrates my maxim that nothing wet ever fits on even an HLV while everything dry comfortably fits on an EELV class launcher. Inability to refuel in orbit is a much bigger constraint than limitations on launch vehicle payloads. Essentially, that's just the rocket equation for you.

Not that we necessarily need a larger lander, but it is good to know that a Lagrange based architecture (even using just hypergolics and EELV class launchers) doesn't impose extra constraints on landed mass compared to Constellation!

You could make the crasher stage use LOX/methane too (or hypergolics, my preference) and make it refuelable straight away, and delay the switch to LOX/LH2 until there are commercial cryogenic depots. And buying hypergolics or LOX/methane at L1/L2 will stimulate the development of such depots. Buying all lander propellant this way would give a bigger boost than buying just the ascent propellant. Using a single stage fully reusable lander (which could still be modular so you could swap out worn out components) would require even more propellant and fewer spacecraft while using about the same amount of money. This would give an even bigger boost, but would be more challenging thrust-wise, depending on the size of the lander.

Note that if you're assuming the existence of a SEP tug it is silly to prefer chemically transported LOX/LH2 over electrically transported LOX/methane or hypergolics at L1/L2.

Also note that if you somehow wanted to use LOX/LH2 straight away, you could launch just the LH2 straight to L1/L2 with an EELV Heavy just before the mission, and launch the LOX at a more leisurely pace. The high O/F ratio of LOX/LH2 is our friend here.
« Last Edit: 12/04/2011 08:48 AM by mmeijeri »
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Offline hektor

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Once again: the fifth ATV will be the final ATV. So please stop imagining scenarios where ATVs are used as space station or exploration modules. The industrial structure is being disbanded, the main equipment is no longer produced, it is exactly like the Shuttle, on a smaller scale.

ESA is now looking at this Orion Service Module derived from the ATV. Time will tell if this option will work.
« Last Edit: 12/04/2011 08:55 AM by hektor »

Offline mmeijeri

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Once again: the fifth ATV will be the final ATV.

Are you sure about this? I thought they were still fighting over it, just as with Ariane 5 ME / vs Ariane 6.
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Offline mmeijeri

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If the Depots evolved from Hypergolic to Cryogenic or liquid methane/LOX technologies, suddenly missions to the Martian Moons or even the Martian surface itself start to look attractive with Falcon Heavy!

Backed by SEP (or RLVs) even hypergolics would be good enough, but I don't think cryogenic depots are the long pole. We'd likely have depots before we were ready to send humans to Mars or the moons of Mars even though they are not strictly necessary for it.

Quote
And I mentioned an enhanced Delta IV-H only because that booster can be upgraded a fair way for relatively little money (compared to SLS) and leaving its existing launchpads largely alone.

Not to mention the fact that a larger cryogenic stage than current EELV upper stages would be desirable anyway for use as an EDS (even from L1/L2). ACES would be the obvious choice and it just so happens that that would give you EELV Phase 1. It would also be a step on the way to an ACES depot.

Again, I find it ironic that while I was looking for a way to get rid of an SDLV US and thought that keeping the large Shuttle first stage components and using a smaller EELV upper stage would have some value, it turns out that having a larger US on existing EELV first stages is actually more useful!
« Last Edit: 12/04/2011 11:36 AM by mmeijeri »
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Offline clongton

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There isn't much wrong with using a crasher stage, but I wouldn't want to use a prefueled stage launched all the way to L1/L2 for it. If the crasher is refuelable too you've essentially lifted all size constraints from the lander. This was first pointed out to me by (get this) Chuck Longton.

What's the slam for?
Chuck - DIRECT co-founder
I started my career on the Saturn-V F-1A engine

Offline mmeijeri

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What's the slam for?

Not a slam, just more irony. You're not generally known as a proponent of eliminating the need for HLVs.
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Offline Rocket Science

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I like the Reusable Lander concept, but how about saving some money and speed up development. Use Orion as a basis for the Lander as well. They could transform the demo flight with the Delta upper stage into a Lander similar to the Phoenix. No need to develop a pressure vessel for the Lander. They don’t have to retain the heat shield for the Lander. OTOH they could retain it as a back-up contingency vessel to return to Earth.
http://www.nasaspaceflight.com/2011/09/sls-mission-improving-crewed-moon-mission-2019/
http://www.nss.org/settlement/moon/LUNOX.html

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