Author Topic: NASA HLS (Human Landing System) Lunar Landers  (Read 1198733 times)

Online TrevorMonty

Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #100 on: 12/13/2018 03:30 pm »


<snip regolith oxygen extraction question>
To extract O, the regolith is heated with H gas. O bonds with H forming water, with iron being one of by products of this reaction. NB this how to produce iron on moon.
Water now needs splitting by electrolysis to extract O and H. H can be used again to extract more O from regolith by repeating process.

If you have access to water may as well produce LH and LOX for little more energy input.
Sure, if that is the method you are using.
Melt phase electrolysis is also another possibility - broadly how aluminim is made.

Aluminim production facilities are lot more complex, not sure of energy use compared iron production method above.

Offline GWH

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #101 on: 12/13/2018 03:32 pm »
I listened in on the call during Jason Crusan’s Gateway presentation this week. He spent a lot of time discussing the Gateway Lunar Lander. He was specifically asked about ISRU and he said that a fuel combination has not been selected for the lander at this point and that the trade space is open to various types including methalox, hydrolox and hypergolics. There’s an imminent lander study broad agency announcement where they will fund 6-9 month studies to refine the design including propellant selection. He also mentioned that there is a desire to have all three elements be reusable at some point but it will not be a requirement for the initial descent elements. Hope this helps.

Was anything said about how propellant is actually sent to NRHO to enable this "reusable" architecture?  Based on a previous slide, total mass of all ascent & descent stages is 21-27 tonnes ->24 tonnes average. Assuming 0.8 propellant fraction, that's  about 20 tonnes of propellant to be refueled per surface mission.
SLS Block 2 can deliver 45 tonnes TLI, of which Orion is 25.8 tonnes leaving only 19 tonnes available for propellant, tanks and maneuvering to NHRO. This leaves a very tight to impossible margin for a single SLS + Orion to accomplish a lunar landing, or the descent stage is carried as comanifested cargo, in which case you still need to deliver 20 tonnes of propellant to Gateway (in excess of supposed limits of commercial vehicles).

Best case a lunar mission is one SLS Block 2 + Orion + propellant, plus a new descent stage on a commercial vehicle.
Worst case one SLS Block 2 + Orion + Descent vehicle, 2 expendable propellant transfer vehicles sent on commercial vehicles.

Offline clongton

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #102 on: 12/13/2018 03:56 pm »
Was anything said about how propellant is actually sent to NRHO to enable this "reusable" architecture?  Based on a previous slide, total mass of all ascent & descent stages is 21-27 tonnes ->24 tonnes average. Assuming 0.8 propellant fraction, that's  about 20 tonnes of propellant to be refueled per surface mission.
SLS Block 2 can deliver 45 tonnes TLI, of which Orion is 25.8 tonnes leaving only 19 tonnes available for propellant, tanks and maneuvering to NHRO. This leaves a very tight to impossible margin for a single SLS + Orion to accomplish a lunar landing, or the descent stage is carried as co-manifested cargo, in which case you still need to deliver 20 tonnes of propellant to Gateway (in excess of supposed limits of commercial vehicles).

Best case a lunar mission is one SLS Block 2 + Orion + propellant, plus a new descent stage on a commercial vehicle.
Worst case one SLS Block 2 + Orion + Descent vehicle, 2 expendable propellant transfer vehicles sent on commercial vehicles.

Essentially, hypergolic propulsion is a non-starter for any lunar mission profile that is more ambitious than Apollo, especially one based at NHRO. I'm sitting here scratching my head trying to understand how the mission planners could even contemplate the approach they have, knowing full well that it is not practical, sustainable or cost effective. Is it possible? Yes. Is it going to happen like they have envisioned? No.
Chuck - DIRECT co-founder
I started my career on the Saturn-V F-1A engine

Online TrevorMonty

Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #103 on: 12/13/2018 05:45 pm »
Better place to start is ask commercial companies what fuels they can deliver to Gateway and at what cost per kg.

Offline GWH

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #104 on: 12/13/2018 05:57 pm »
https://twitter.com/JimBridenstine/status/1073268965143506945

Quote
Using the Gateway to land astronauts on the Moon allows the first building blocks for fully reusable lunar landers. Initially NASA expects two of the lander elements to be reusable and refueled by cargo ships carrying fuel from Earth to the Gateway. The agency is also working on technologies to make rocket propellants using water ice and regolith from the Moon.  Once the ability to harness resources from the Moon for propellant becomes viable, NASA plans to refuel these elements with the Moon’s own resources. This process, known as in-situ resource utilization or ISRU, will make the third element also refuelable and reusable."

Quote
NASA intends to release a solicitation under the second Next Space Technologies for Exploration Partnerships (NextSTEP-2) Broad Agency Announcement on January 2, 2019 to seek proposals from industry in support of design analysis, technology maturation, system development and integration, and spaceflight demonstrations for a human lunar landing system. An Industry Forum is planned, tentatively scheduled for January 8, 2019 at NASA Headquarters. Confirmation of these dates and additional details will be posted soon.

Will be interesting to see if this is an open solution RFP or if NASA seeks to have bidders conform to their predetermine 3 part lander.  Simply put does SpaceX get to propose Starship? Does ULA have an opportunity to propose XUES? Lockheed and their lander?

Offline A_M_Swallow

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #105 on: 12/13/2018 09:48 pm »
{snip}
Will be interesting to see if this is an open solution RFP or if NASA seeks to have bidders conform to their predetermine 3 part lander.  Simply put does SpaceX get to propose Starship? Does ULA have an opportunity to propose XUES? Lockheed and their lander?

The full FRP has not been issued yet but pre-solicitation NNH19ZCQ001K_APP-E says:
https://www.fbo.gov/index?s=opportunity&mode=form&tab=core&id=49ada55b3e532f7cb2cfe04b126f0ee0
Quote
{snip}
This NextSTEP-2 Appendix E will include a NASA reference human lander architecture configuration. The full architecture will include a Descent Element, Ascent Element, Transfer Vehicle, Refueling Element, and Surface Suit. NASA plans to launch the first demonstration mission in 2024. The minimum objective of this mission is to demonstrate a lunar surface landing with one or more Descent Elements capable of supporting a future human lander that includes both Descent Element and Ascent Element. Contracts awarded under Appendix E may have multiple phases. The first will be for brief studies to mature requirements, tailor applicable standards, procure long-lead parts and implement technology maturation plans for early risk reduction ...

That is a lot of new inspace hardware.

edit: add url
« Last Edit: 12/13/2018 09:52 pm by A_M_Swallow »

Offline GWH

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #106 on: 12/14/2018 01:30 pm »
With a fuel depot infrastructure the single stage lander would not be too large for SLS or even a smaller vehicle like New Glenn or Falcon Heavy as it could act as it's own departure stage.

Yeah, it seems odd that they're talking about refueling and reuse of stages in lunar orbit but act as though you couldn't do the same thing in LEO--even if the rocket isn't a lander with legs on it.

~Jon

The lead up to the RFP suggests the descent stage lander is to be made reusable with future use of ISRU.
That doesn't seem like a very good fit for a 3 stage architecture, as the descent stage would now need to be significantly overbuilt to serve the two way trip of a tanker variant to refill all 3 stages for a repeat mission.

While I'd need to crunch a few numbers on that to determine how much, I have a pretty good intuition this leads to a very mass inefficient architecture. One that would be much better served by large single stages vehicles that are - of course - refueled in LEO initially to ferry propellant, and in the future when refueling on the lunar surface is possible are perfectly sized to travel to the gateway and return to lunar surface.

Offline libra

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #107 on: 12/14/2018 03:46 pm »
I don't understand... while SSTO is extremely hard on Earth (9.5 km/s) the Moon seems a little easier (2.5 km/s, one way, 5 km/s, two way). It is a little sad NASA can't build a lunar SSTO. Is maintenance or reliability an issue ? on Earth there are entire OPF for maintenance. Around the Moon, there is none.

Offline JonathanD

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #108 on: 12/14/2018 05:35 pm »
I don't understand... while SSTO is extremely hard on Earth (9.5 km/s) the Moon seems a little easier (2.5 km/s, one way, 5 km/s, two way). It is a little sad NASA can't build a lunar SSTO. Is maintenance or reliability an issue ? on Earth there are entire OPF for maintenance. Around the Moon, there is none.

I think it's a size issue.  In order to have reasonable payload to the surface (including squishy kerbals to run around and look at things) and have it fully reusable, you'd have to make it a lot bigger, and I just don't think they believe they'll have the budget for it.  If you can dump the descent stage your requirements become a lot easier.  But I agree with you, it's a bit sad, especially in the context of all this "reusability" and "sustainable" talk.  The reality is a relatively small number of components will be reusable here.  Certainly the gateway itself, but as as been specified, it is not particularly large.  And then two of three lander stages (though it is unclear how reusable the ascent stages will be, how they will be refueled and maintained at the LOP-G, etc).  So LOP-G is reusable by default, and maybe we'll have a partially reusable lander, and unclear on Orion.  That's pretty much it.  SLS is certainly not reusable, and based upon the current proposed pathway, the project calls for a hefty number of SLS launches that are absolutely not cheap.

I understand why NASA is going this route.  A project of this scale on or around the moon requires heavy lift, if not super heavy lift vehicles to really make sense from a payload size sense.  The only vehicle that NASA has confidence in actually existing any time soon is SLS.  Yes there are commercial companies with plans, but we have to look at it from NASA's perspective: they are still plans, they are out of NASA's control, and they are not guaranteed.  There's no way they can budget around that.  That's why they only have a few vague commercial delivery placeholders in the LOP-G plan as it is today.  So if you are "stuck" with SLS/Orion, and you know it's going to get funded for the near- to mid-term, enough for a half dozen flights at least, that is the architecture you have to look at.  With that in mind, there are a few very key pieces.  1) SLS/Orion is not designed as a direct lunar mission architecture, it is for exploration in space; Orion is a spacecraft, it's can't land anywhere except back on Earth for recovery.  There are no plans or funding for a fully-reusable lander that would fit on SLS.  Think about how much Orion costs!  There is no way they could get a lander together for a direct mission any time soon due to development time and expense.  2) SLS/Orion can get to low lunar orbit, but it can't get back with enough fuel margin.  Also a low lunar orbit requires more station keeping dV for a station there, which would make it a fuel challenge for LOP-G.  This document is the best I've found at describing the reasons behind the orbit (See Page 8, Table 6): https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20150019648.pdf.  So the NRO orbit makes sense from an Orion and stationkeeping perspective, and has the tertiary benefit of providing access to more parts of the moon, better communication, better sunlight, and better thermal conditions.

So as far as I see it the bottom line is that if NASA is going to do anything on our around the moon in the next decade (which they've been directed to do by the Pres. administration for better or worse), this is the only plan they can really afford to do using the expected available launch architecture (SLS/Orion) without getting into speculating about unknown launch vehicles from private companies that may never come to fruition or may never meet NASA's requirements.  And it's difficult to blame them for that, not only would it be hard to budget and strategize around unknowns, the commercial players themselves can be an enigma.  Blue Origin is absolutely proceeding along its own timeline and does not appear to be in any rush.  SpaceX has grandiose plans but which change dramatically every two months.  Could one of these operators become a potential partner for future operations on the Moon or Mars?  Sure, but there is no assurance that it will be a possibility.  NASA knows SLS is being built, and they know they won't be getting a ton of Moon funding beyond that, so that's what they are working with.  Does that mean a lot of compromises?  Absolutely.  I just hope those compromises aren't so significant that we are left with a very expensive space program with very limited capabilities.  When the Shuttle was designed there were a ton of capabilities piled onto that craft that contributed to the expense of the program over time, I'd hate to see those mistakes repeated.
« Last Edit: 12/14/2018 05:37 pm by JonathanD »

Offline A_M_Swallow

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #109 on: 12/14/2018 08:51 pm »
Specification of possible reusable tanker vehicle flying full from LEO to low lunar orbit (LLO) and empty back to LEO.

Using Wikipedia data.

Payload of SLS Block 1 to LEO is 95 tonne.
Payload of Falcon Heavy to LEO is 63.8 tonne.
Payload of Falcon 9 expendable to LEO is 22.8 tonne.
Payload of Atlas V to LEO is 20.5 tonne.

Dry mass of tanker including main engine, RCS, its own fuel tanks, structure, avionics, solar panels, sun shield, cooling system, docking system, pump and payload tank is To Be Determined (TBD).

Delta-v LEO to LLO using chemical thrusters is 4.04 km/s one-way
Delta-v LEO to LLO using electric propulsion is 8.0 km/s one-way

Masten Broadsword engine producing 35,000 lbf thrust vacuum burning methane/LOX Isp ~321.
Masten Machete engine producing 1,000 lbf burning MXP-351 Isp 322 s (probably 4 off engines).
VASIMR producing 5 N (1.1 lbf) burning Argon Isp 5,000 s.

How much could such a tanker deliver?

Online TrevorMonty

Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #110 on: 12/15/2018 01:51 am »
Specification of possible reusable tanker vehicle flying full from LEO to low lunar orbit (LLO) and empty back to LEO.

Using Wikipedia data.

Payload of SLS Block 1 to LEO is 95 tonne.
Payload of Falcon Heavy to LEO is 63.8 tonne.
Payload of Falcon 9 expendable to LEO is 22.8 tonne.
Payload of Atlas V to LEO is 20.5 tonne.

Dry mass of tanker including main engine, RCS, its own fuel tanks, structure, avionics, solar panels, sun shield, cooling system, docking system, pump and payload tank is To Be Determined (TBD).

Delta-v LEO to LLO using chemical thrusters is 4.04 km/s one-way
Delta-v LEO to LLO using electric propulsion is 8.0 km/s one-way

Masten Broadsword engine producing 35,000 lbf thrust vacuum burning methane/LOX Isp ~321.
Masten Machete engine producing 1,000 lbf burning MXP-351 Isp 322 s (probably 4 off engines).
VASIMR producing 5 N (1.1 lbf) burning Argon Isp 5,000 s.

How much could such a tanker deliver?
ULA distributed launch paper had Vulcan Heavy using 2 launches, delivering 20t to GSO, similar DV to Gateway.

A Vulcan + NG distributed launch should be good for 23t and probably cheaper. Another advantage of using this combination is launches can be days apart as they launch on separate pads. 2xVulcan would need 2-3wks for 2nd launch.



Offline KelvinZero

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #111 on: 12/15/2018 03:15 am »
I don't understand... while SSTO is extremely hard on Earth (9.5 km/s) the Moon seems a little easier (2.5 km/s, one way, 5 km/s, two way). It is a little sad NASA can't build a lunar SSTO. Is maintenance or reliability an issue ? on Earth there are entire OPF for maintenance. Around the Moon, there is none.
Just throwing out a random idea: a lunar lander that returns to orbit leaving its landing propellant tanks and legs behind. These are designed to be convertible to moon-base elements on the surface.

Offline GWH

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #112 on: 12/15/2018 03:42 am »
How much could such a tanker deliver?
ULA distributed launch paper had Vulcan Heavy using 2 launches, delivering 20t to GSO, similar DV to Gateway.

A Vulcan + NG distributed launch should be good for 23t and probably cheaper. Another advantage of using this combination is launches can be days apart as they launch on separate pads. 2xVulcan would need 2-3wks for 2nd launch.

Taking a quick guess at the dV of NASA's lander, ISP on the low side  (330) and wet mass at the max range (13 tonnes) I estimate a crew capsule of 3.5 tonnes.
 
A XEUS lander operating from NHRO to lunar surface and back would need to make 5.8km/s round trip.
Assuming 6 tonnes dry mass, plus 3.5 tonne crew capsule and 451s IPS this requires a propellant load of 27 tonnes.
An ACES tanker operating from LEO and fully refueled to 68 tonnes could transport 26 tonnes of propellant to gateway. Distributed lift assumes some extra tankage and the like, so 2xVulcan Heavy may not quite cut it.
*However it should be noted that ACES is now a 77 tonne propellant load, not the old 68 tonne. It is highly likely that a full ACES tanker from LEO would be completely sufficient to refuel this XEUS lander.

Now lets look at the big picture:
- Even if flying as a payload on Vulcan rather than an upper stage a XUES lander can be flown to gateway empty on a single rocket (or with a little bit of extra propellant to make up any shortfall).
- Note that if you are using ACES (or a vehicle with the same functionality) you have a smart stage tug that saves development of supply vehicles and can also transport excess propellant on those missions.
- Total commercial flights of heavy lifters is 3 for the 1st mission same as the NASA concept.
- Follow up missions would require 2 to 2.5 Vulcan's to refuel. *Substitute your favorite heavy launcher here.
- Comparatively NASA repeat mission need a new descent stage and at least one expendable propellant tanker for about 20 tonnes of propellant for the 2 reused stages. Two launches in total.
- Only one "stage" needs to be designed.
- Total mass flown to NHRO for the very first lander mission is 37 tonnes, NASA 3 stage concept is 33 to 42 tonnes.
- The assumed dry mass of XUES is suitable for a full 68mt tank. A shortened version would perform significantly better, dropping propellant requirement to 21 tonnes, total mass to NHRO for 1st mission is only 29 tonnes.
- With a fleet of in space tankers, instead of simply paying lip service to making use of Lunar propellant, the possibilities in deep space open up drastically.

EDIT: But what if abort to orbit is needed?
- Build a separate ascent vehicle with single RL-10: 9.2mt wet, 1.2t dry, 3.5t payload.
- One single XUES can transit from LEO to Gateway, and refuel the ascent stage while still having enough propellant to refuel an ascent vehicle and take it down the the lunar surface.
- A total of 2 launches is required plus lots of margin for a XEUS and its "distributed lift" refueling in LEO.
- Eventual reuse of all those empty XUES's on the lunar surface is a possibility.

EDIT 2: Since the plan is for using the descent lander first for cargo, how does XUES plus refeulling compare?
- Max cargo from LEO to Lunar surface with LEO refueling: 17.5 tonnes
- Max cargo from LLO to Lunar surface with LLO refuel of 24 tonnes: 35 tonnes (limited by Vulcan lift to LEO)
- Refueling from anywhere further up the gravity well than LEO results in much better performance
Unlike the self imposed limit on max cargo with the 3 stage & NHRO refuel only system proposed, there really isn't any limit on what can be delivered to the lunar surface if one steps outside the tyranny of the architecture NASA is proposing.
« Last Edit: 12/16/2018 05:04 pm by GWH »

Offline Proponent

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #113 on: 12/15/2018 12:49 pm »
I understand why NASA is going this route.  A project of this scale on or around the moon requires heavy lift, if not super heavy lift vehicles to really make sense from a payload size sense.  The only vehicle that NASA has confidence in actually existing any time soon is SLS.  Yes there are commercial companies with plans, but we have to look at it from NASA's perspective: they are still plans, they are out of NASA's control, and they are not guaranteed.  There's no way they can budget around that.

Sure they can.  Put the companies under contract to provide a certain launch capability by a certain date.  NASA has not developed a launch vehicle since the early 1980's and has not developed one that delivered on its specs since the 1960's.  ULA and SpaceX are both more credible rocket builders than is NASA.

Offline Slarty1080

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #114 on: 12/16/2018 05:54 pm »
I understand why NASA is going this route.  A project of this scale on or around the moon requires heavy lift, if not super heavy lift vehicles to really make sense from a payload size sense.  The only vehicle that NASA has confidence in actually existing any time soon is SLS.  Yes there are commercial companies with plans, but we have to look at it from NASA's perspective: they are still plans, they are out of NASA's control, and they are not guaranteed.  There's no way they can budget around that.

Sure they can.  Put the companies under contract to provide a certain launch capability by a certain date.  NASA has not developed a launch vehicle since the early 1980's and has not developed one that delivered on its specs since the 1960's.  ULA and SpaceX are both more credible rocket builders than is NASA.
I have some sympathy for NASA at the moment on this basis. But it will be interesting to see what they say when a superheay commercial launch vehicle does become operational. I hope they won't migrate from excuse to excuse - it's not fully proven yet, it hasn't got the exact xyz we want, it would cost too much to build an adaptor... at that point sympathy would start to drain away. But I would give them the benefit of the doubt for now for sure.
My optimistic hope is that it will become cool to really think about things... rather than just doing reactive bullsh*t based on no knowledge (Brian Cox)

Offline Proponent

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #115 on: 12/17/2018 09:58 am »
I have some sympathy for NASA at the moment on this basis.

Why?  If the problem is that NASA can't be sure the commercial capabilities will materialize, there is an easy way to fix it.  Put a proven rocket-building company under contract to provide a stated capability by a fixed date.  That won't eliminate all of the risk, but it would be much less risky in terms of cost and schedule than relying on NASA to complete SLS.

This ignores, of course, the bigger issue, which is that NASA has not shown it needs super-heavy lift.

I have some sympathy for NASA, in that in building SLS it's just doing what it's been ordered to do by Congress (though there are plenty at NASA who would want to do SLS anyway).

Offline JonathanD

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #116 on: 12/17/2018 02:09 pm »
Put a proven rocket-building company under contract to provide a stated capability by a fixed date.  That won't eliminate all of the risk, but it would be much less risky in terms of cost and schedule than relying on NASA to complete SLS.

Who do you think is building SLS, NASA employees?

Offline Proponent

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #117 on: 12/17/2018 09:44 pm »
Put a proven rocket-building company under contract to provide a stated capability by a fixed date.  That won't eliminate all of the risk, but it would be much less risky in terms of cost and schedule than relying on NASA to complete SLS.

Who do you think is building SLS, NASA employees?

NASA designed SLS, manages its development and intends to buy SLS rockets which it will launch itself.  Any other time the US government wants to launch something into space, it buys launch services, leaving design, management and launch of the rockets themselves to the contractor.

EDIT:  Added words after first comma in last sentence.
« Last Edit: 12/17/2018 09:52 pm by Proponent »

Offline ncb1397

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #118 on: 12/17/2018 09:46 pm »
Put a proven rocket-building company under contract to provide a stated capability by a fixed date.  That won't eliminate all of the risk, but it would be much less risky in terms of cost and schedule than relying on NASA to complete SLS.

Who do you think is building SLS, NASA employees?

NASA designed SLS, manages its development and intends to buy SLS rockets which it will launch itself.  Any other time the US government wants to launch something into space, it buys launch services.

orbit, yes....
space, no....
« Last Edit: 12/17/2018 09:46 pm by ncb1397 »

Online Coastal Ron

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Re: NASA HLS (Human Landing System) Lunar Landers
« Reply #119 on: 12/17/2018 09:55 pm »
Put a proven rocket-building company under contract to provide a stated capability by a fixed date.  That won't eliminate all of the risk, but it would be much less risky in terms of cost and schedule than relying on NASA to complete SLS.

Who do you think is building SLS, NASA employees?

NASA designed SLS, manages its development and intends to buy SLS rockets which it will launch itself.  Any other time the US government wants to launch something into space, it buys launch services.

orbit, yes....
space, no....

All of NASA's BEO missions are launched on commercial rockets, so yes, space too.
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

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