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#26 2006-10-19 01:05:11

cIclops
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Registered: 2005-06-16
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Re: Altair - Lunar Lander (LSAM) - status

At the Exploration update 18 October, Jeff Hanley said that the Lunar Lander concept study had been reviewed. Over 38 different lander configurations were considered, these were downselected to six that will be worked into a new conceptual LSAM design. Results from this work will be made public later this year.


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#27 2006-10-19 11:53:02

RedStreak
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Re: Altair - Lunar Lander (LSAM) - status

Over 38 different lander configurations were considered, these were downselected to six that will be worked into a new conceptual LSAM design.

So six eh?  I wonder if Lockheed's was among them.

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#28 2006-10-27 12:26:52

publiusr
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Re: Altair - Lunar Lander (LSAM) - status

Interesting

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#29 2006-11-07 06:56:21

cIclops
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Re: Altair - Lunar Lander (LSAM) - status

Almost missed this one: Conceptual design study

NASA/GRC plans to release a Request for Proposal (RFP) for 1) a conceptual design study to evaluate and optimize a mass efficient, low power, reduced propellant loss approach for the propellant inventory and thermal control of cryogenic propellants for the Crew Exploration Vehicle Service Module (SM) and Lunar Surface Access Module (LSAM) exploration missions, and 2) design and fabrication of two cryogenic propellant RCS feedline manifolds to support ground based RCS testing at a NASA facility.

Background: NASA is currently developing the propulsion system concepts for exploration missions including a near term human return to the lunar surface and an eventual human mission to Mars. The propulsion options under consideration include the use of cryogenic propellants – liquid oxygen (LO2), liquid methane (LCH4) and/or liquid hydrogen (LH2) for several of the crewed, low gravity portions of the mission, that is, a Service Module (SM) for orbit maneuvering to the ISS and for orbit insertion required for lunar exploration missions and the Lunar Surface Access Module (LSAM) for Lunar orbit capture, descent to the lunar surface and ascent to lunar orbit.

These concepts will require the cryogenic propellant inventory in the vehicle to be maintained during ground hold, the launch transient, during a long term, quiescent in-space storage at the ISS, for lunar injection, and during lunar operations. The cryogenic propellants must also be delivered in a vapor free condition to the Reaction Control Systems (RCS) thrusters and the Orbital Maneuvering Systems (OMS) engines of the vehicle.

A LO2/LCH4 engine is still possible!


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#30 2006-11-22 09:14:44

cIclops
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Re: Altair - Lunar Lander (LSAM) - status

Good material from Doug Stanley (ESAS team leader) discussing the propellants options:

Keep trade space open for LSAM Ascent Stage
- Continue trading Options 1, 4a, and 4b (Hypergol, Hydrogen, Methane)
- Lunar architecture with hypergol baseline is far from closing with current requirements
- Performance benefits of alternative propellants greatly magnified by higher “gear ratio” (i.e., smaller ascent stage leads to smaller descent stage and smaller EDS)
- LO2/LH2 ascent stage is more expensive/complex, but provides very high performance benefits (>60klbs in EDS and LSAM weight) using Broad Area Cooling technologies
- Investigate common engine for ascent and descent stages and common OMS/RCS
- LOX/Methane ascent stage is lower cost and risk than LO2/LH2 solution but has reduced performance benefits (>25klbs in EDS and LSAM weight)
- LO2/LH2 only feasible option for descent stage due to performance requirements
- Consider “minimal” ascent stage to satisfy lunar DRM requirements set
- Continue funding Methane technology program
- Immediately fund LH2 broad area cooling technologies, which has very large cost/benefit investment ratio
<edit>
..as a result of our study and the interim Lunar Architecture Team results, the requirement is being changed back to 15 days LEO loiter (a la ESAS). If the 15 days is exceeded, you could wait longer and have reduced capabilities. In reality there is a lot of margin built in for worst case burns and loiter times and plane changes that would have a VERY low probability of all occuring on the same mission. At some point, if it got critical enough you could send the lander on autonomously to land near the base and deliver its cargo with the people following on a later mission. We assume passive insulation on the descent stage, although there is an option of using broad area cooling technologies if the loiter time were longer.

The design approach to boil-off mitigation that we took for cryo propellants would work fine for even the 90-day loiter (the 6 month lunar surface stay is more significant). For the methane case we designed a thermodynamic vent system (sorry the schematics are on charts labelled SBU) that allows the tank pressure to vary to mitigate boil-of. it also uses MLI and insulation of heat leak sources. The tanks are design to operate at 75 psi higher pressures than with a purely passive system. When the propellants are loaded they are subcooled by controlling tank pressure. As the mission goes on, the tank pressure is slowly allowed to rise to eliminate boil-off. With this approach, a 6-month mission can be accommodated with no significant boil-off of oxygen or methane. This was the approach we assumed in ESAS, but we did a much more detailed thermal analysis this time. For the LH2/LO2 case we studied different approaches and settled on a broad area cooling approach that used a continuous network of tubing embedded in the tank MLI that circulates helium for cooling. A redundant set of cryopumps drives the closed loop helium system, keeping the tanks at 100K. For the 6-month mission, this eliminates the O2 boil-off and reduces the H2 boil-off by 70 %.
<edit>
There are really two different approaches under study.

The ESAS baseline type approach replaced the crew habitat with a cargo pallet. Since you don't have to push Orion, you get over 20 metric tons to the surface. This could be done with an ESAS-like "top-loader", but you have to get the cargo down from a fairly sigificant height. There are a lot of different unloading concept which all have there strengths and weaknesses. Or this could with a "bottom loader" that we also examined in ESAS and since, where the cargo is much closer to the surface...not sitting on top. There are many different ways to configure such a lander, but they often add weight over the top-loaders.

Another approach is to take cargo or additional habitat with the minimal ascent stage and leave it on the surface...this could also be a top or bottom loader (hard to envision without drawings I know!). The top-loading version would be similar to that shown in section 4.2.5.1.3.6 of the ESAS Final Report. A bottom-loading version (sort of) is shown in Figure 4.43 and some other options in Figure 4.42....there are a lot better designs done since these...The Lockheed paper mentioned above has another approach to getting the crew/cargo near the surface...


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#31 2006-12-04 16:21:38

cIclops
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Re: Altair - Lunar Lander (LSAM) - status

landerconceptol7.jpg
Ripped from Dec. 4, 2006 Briefing Charts (1.2 MB PDF)

Current LSAM lander concept as presented at the Lunar architecture briefing today.


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#32 2006-12-13 05:08:24

cIclops
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Re: Altair - Lunar Lander (LSAM) - status

Lunar landing  and surface animation  ... if you have the bandwidth checkout the HD 1080i version (120MB)


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#33 2007-01-05 13:22:27

SpaceNut
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Re: Altair - Lunar Lander (LSAM) - status

LSAM mock-up revealed

Suit1.JPG

The mock-up is a wooden construction which stays true to current designs that have been released by NASA Constellation, with a middle part of the structure showing the ascent engine cover, meaning the astronauts will be located at stations around the perimeter of the module's interior.

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#34 2007-01-05 17:13:34

cIclops
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Re: Altair - Lunar Lander (LSAM) - status

AFAIK NASA haven't released any internal designs for the LSAM, so what current design is it true too? This is part of another attempt by NSF to get money for "acquired" NASA material.


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#35 2007-01-19 11:35:09

cIclops
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Re: Altair - Lunar Lander (LSAM) - status

Why did the Apollo lunder module and the current designs all have four landing legs? Three ought to be enough and should save weight.


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#36 2007-01-19 12:07:13

ftlwright
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Re: Altair - Lunar Lander (LSAM) - status

Why did the Apollo lunder module and the current designs all have four landing legs? Three ought to be enough and should save weight.

This is only true if landing on a flat surface.  There are landing situations that would make a three leg lander unstable and highly dependent upon weight distribution, surface inclination, etc.

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#37 2007-01-26 21:56:17

SpaceNut
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Re: Altair - Lunar Lander (LSAM) - status

Ascent Stage: Dry mass 4000 kg, inert mass 5600 kg, cargo is only 800 kg, propellant 4500 kg. Total 10200 kg.
Descent stage: Dry mass 5100 kg, inert mass 7000 kg, propellant 27500 kg. Total 35000 kg.

So total LSAM is 45200 kg.

While these numbers of course change with regards to the EDS capabilities.
The sooner we begin on the moon lander the quicker we will get to go to mars.

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#38 2007-01-27 08:59:42

RedStreak
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Re: Altair - Lunar Lander (LSAM) - status

Ascent Stage: Dry mass 4000 kg, inert mass 5600 kg, cargo is only 800 kg, propellant 4500 kg. Total 10200 kg.
Descent stage: Dry mass 5100 kg, inert mass 7000 kg, propellant 27500 kg. Total 35000 kg.

So total LSAM is 45200 kg.

While these numbers of course change with regards to the EDS capabilities.
The sooner we begin on the moon lander the quicker we will get to go to mars.

Agreed, or at least the EDS stage.  Considering the needs for aerobraking and reentry a Martian lander may turn out to be far different than a Lunar one, although possbly they may share a few systems depending on what needs beyond an aeroshell a Mars lander requires.

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#39 2007-01-27 09:11:41

cIclops
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Re: Altair - Lunar Lander (LSAM) - status

Ascent Stage: Dry mass 4000 kg, inert mass 5600 kg, cargo is only 800 kg, propellant 4500 kg. Total 10200 kg.
Descent stage: Dry mass 5100 kg, inert mass 7000 kg, propellant 27500 kg. Total 35000 kg.

So total LSAM is 45200 kg.

While these numbers of course change with regards to the EDS capabilities.
The sooner we begin on the moon lander the quicker we will get to go to mars.

What is the source for these numbers SpaceNut?


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#40 2007-02-26 03:12:04

cIclops
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Re: Altair - Lunar Lander (LSAM) - status

lsamci2.jpg
Ripped from John  Connolly (ESMD) Charts (7MB PDF) - 20 Feb 2007

These charts also contain details of  7 Lunar Lander concepts from different NASA centers. Check them out!


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#41 2007-02-26 07:18:42

SpaceNut
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Re: Altair - Lunar Lander (LSAM) - status

I see that Nasa is doing more Engine developement of deravitives for the lander. With a tight budget that may get even tighter as the years pass is this wise?

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#42 2007-02-26 07:29:57

GCNRevenger
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Re: Altair - Lunar Lander (LSAM) - status

The avionics are going to be largely based on Boeing airliner cockpits which we already have, which makes the engine(s) the biggest hurdle to actually building the vehicle. If we don't start now, when?


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#43 2007-02-26 08:27:45

cIclops
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Re: Altair - Lunar Lander (LSAM) - status

I see that Nasa is doing more Engine developement of deravitives for the lander. With a tight budget that may get even tighter as the years pass is this wise?

The problem is the budget getting tighter not NASA practicing good engineering by developing alternative solutions.

If only more people would support the VSE/ESAS instead of trying to wreck it. If they think that their favorite project will get funded instead, they are dreaming. If NASA loses its budget that money will simply go elsewhere in the government.


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#44 2007-02-26 13:35:06

SpaceNut
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Re: Altair - Lunar Lander (LSAM) - status

Not to bad mouth Nasa cIclops, but I see a trend in that what we have off the shelf is not good enough to use to reach the goal in support of the vision.

Why did I comment on the deravitive engine developement it was that we have seen that Nasa has gone from 4 segment to 5 SRB of course later explained, that the RS68 is to go though a simular evolution to alter it for higher ISP and possibly to man rate, that the j2-S is to become a J2-X also to achieve a higher ISP ect...

What Nasa needed IMO was to take a short cut at least to LEO so that shuttle would end and that we could continue manned flight without relying on Russia for flights.

So why can we not just use the RL-10 the way that it is with the new cockpit GCNRevenger, is it as well becuase we need more ISP from it as well?

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#45 2007-02-26 15:29:06

RedStreak
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Re: Altair - Lunar Lander (LSAM) - status

Looking through the various lander concepts, I think the Langely Cargo Star concept wouldn't be bad for an unmanned concept.  Its manned counterpart however I am not so sure on - alot of the lander concepts seem to incorporate disposable descent stages and I mean bulky rocket stages that crash into the moon.  That generates alot of space junk and puts any future habitats at risk.  The landers themselves look good but if NASA choses one of them I hope they'll eventually develop a lander without such a stage in another 10 to 15 years.

Overall the MSFC lander looks like it has the most potential in my opinion.

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#46 2007-02-26 16:07:19

cIclops
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Re: Altair - Lunar Lander (LSAM) - status

lcslhp5.jpg

Ok here it is.

It's the only horizontal lander of the 7 and leaves the descent stage on the surface as does the MSFC, JSC and the GSFC-JSC-GRC landers. Why does it have an ascent stage as it's a cargo lander?

The JPL MobiLander is an interesting idea, it has incredible mobility and cleverly combines the sortie and outpost missions using the ATHLETE rover.


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#47 2007-02-27 22:50:36

SpaceNut
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Re: Altair - Lunar Lander (LSAM) - status

NASA Strategic Management Council Meeting 2 November 2006: Status of the Exploration Strategy and Architecture Activities

http://www.spaceref.com/news/viewsr.html?pid=23474

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#48 2007-02-28 07:29:29

GCNRevenger
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Re: Altair - Lunar Lander (LSAM) - status

Looking through the various lander concepts, I think the Langely Cargo Star concept wouldn't be bad for an unmanned concept.  Its manned counterpart however I am not so sure on - alot of the lander concepts seem to incorporate disposable descent stages and I mean bulky rocket stages that crash into the moon.  That generates alot of space junk and puts any future habitats at risk.  The landers themselves look good but if NASA choses one of them I hope they'll eventually develop a lander without such a stage in another 10 to 15 years.

Overall the MSFC lander looks like it has the most potential in my opinion.

Nonsense

The disposable stage is absolutely not a problem, the Lunar gravity will keep any impact debries confined to the impact site just fine. It does a great job with meteors, why not spent rocket stages? These expendable stages are also quite similar to Centaur, which would lower development costs and decrease the structure mass of the lander. Eliminates the headache of staging on the Lunar surface instead of the decades-proven Centaur staging. They simply don't weigh very much and aren't moving all that fast at impact, they are after all there to slow down the vehicle.


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#49 2007-02-28 07:32:38

cIclops
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Re: Altair - Lunar Lander (LSAM) - status

The disposable stage is absolutely not a problem, the Lunar gravity will keep any impact debries confined to the impact site just fine. It does a great job with meteors, why not spent rocket stages?

Because human beings are the only part of the universe that is not allowed to change anything smile


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#50 2007-05-02 13:42:34

cIclops
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Re: Altair - Lunar Lander (LSAM) - status

Testing Under Way On RL-10 - 2 May 2007

Engineers at Pratt & Whitney Rocketdyne (PWR) are dissecting their data after running a specially equipped RL-10 rocket engine at 10 percent of its full 13,000-pound thrust in a series of tests aimed at using the venerable cryogenic engine for the descent stage of NASA's planned lunar lander.

PWR uses a bypass valve to route hydrogen around the turbopump that feeds propellant into the combustion chamber, slowing the turbomachinery to throttle the engine back, says Chris Moore, who runs the exploration advanced technology program at NASA headquarters.

Tests last year at the PWR facility in West Palm Beach, Fla., showed combustion instability at low throttle levels, so a new test series just wrapping up is trying out different mixture ratios of liquid hydrogen fuel and liquid oxygen (LOX) to ease the problem.

"The preliminary results show it does have an effect," Moore says. A cluster of four throttleable RL-10s is envisioned as one way to ease the descent stage of the planned Lunar Surface Access Module to the moon's surface. Moore says early data show that the 10/1 throttling range built into the test engine may not be needed for the lunar mission, and that as little as 4/1 or 5/1 may suffice.

The RL-10 is one of two engines under consideration for the lander-descent application. Northrop Grumman is in the early stages of designing a pintle engine like the one that lowered the Apollo-era Lunar Excursion Module to the surface, except that the new version would use cryogenic instead of storable propellant to get the performance needed to send the lander to any point on the lunar surface, Moore says.

The pintle engine design avoids the combustion instability issue at low throttle, he adds. Advanced-technology planners hope to have a prototype descent engine ready by the time the LSAM goes into preliminary design review, now scheduled for 2013.


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