SLS Upper Stage Changes While Software Problems Linger
Statement by Acting NASA Administrator Robert Lightfoot – Hearing on NASA FY2019 Budget
“NASA plans to launch an initial, uncrewed deep space mission, Exploration Mission-1 (EM-1), in FY 2020. The mission will combine the new heavy-lift SLS with an uncrewed version of the Orion spacecraft on a mission to lunar orbit. A crewed mission, EM-2, will follow in 2023. The FY 2019 budget fully funds the Agency baseline commitment schedule for EM-2 and the Orion spacecraft and enables NASA to begin work on post EM-2 missions. Missions launched on the SLS in the 2020s will establish the capability to operate safely and productively in deep space.”
FY 2019 Budget Hearing – National Aeronautics and Space Administration (Video of hearing)
NASA may fly crew into deep space sooner, but there’s a price, Ars Technica
“NASA will likely launch its first astronauts into deep space since the Apollo program on a less powerful version of its Space Launch System rocket than originally planned. Although it has not been officially announced, in recent weeks mission planners at the space agency have begun designing “Exploration Mission 2” to be launched on the Block 1 version of the SLS rocket, which has the capability to lift 70 tons to low Earth orbit. Acting agency administrator Robert Lightfoot confirmed during a Congressional hearing on Thursday that NASA is seriously considering launching humans to the Moon on the Block 1 SLS. “We’ll change the mission profile if we fly humans and we use the Interim Cryogenic Propulsion Stage (ICPS), because we can’t do what we could do if we have the Exploration Upper Stage,” Lightfoot said.”
Keith’s note: Note that there is no mention of this substantial internal activity in Lightfoot’s prepared statement at the hearing. One has to assuem that they would have rather not talked about this if at all possible. In addition to all of the excellent points raised in this article there is another looming factor that will affect this decision. Readers of NASAWatch will recall that there has been a lot of chaos at NASA MSFC in the safety group that is certifying the SLS flight software. One of the things that scared this team the most was the sad state of current software and what would have to be done to human rate SLS – with the Exploration Upper Stage (EUS) on EM-2. Sources report that the internal consensus was that the software would have to be started from a clean slate in order to human rate the SLS.
But, not only was NASA planning to launch humans on SLS for the first time on EM-2, they were going to launch them for the first time on a launch vehicle configuration that had never flown before (SLS + EUS i.e. Block 1B Crew). The last time NASA did this was STS-1. If this expanded use of Interim Cryogenic Propulsion Stage (ICPS) is going to become the new baseline, sources report that the task of human rating it will be simplified since they can start much earlier. And, when humans do fly on it there will be at least one full-up flight of the SLS+ICPS SLS Block 1 configuration (EM-1) under their belt.
And then, of course, there is the issue of flying probes to Europa on SLS – a task Congress has put on NASA’s agenda. The whole idea behind using SLS was to get there faster. ICPS is not the solution and Falcon Heavy becomes exceptionally competitive if that option comes forward.
That said, the SLS software safety issue is still a mess – as will soon be revealed in internal and external reports on this situation.
– SLS Software Problems Continue at MSFC, earlier post
– This Is How NASA Covers Up SLS Software Safety Issues (Update), earlier post
– MSFC To Safety Contractor: Just Ignore Those SLS Software Issues, earlier post
– SLS Flight Software Safety Issues Continue at MSFC, earlier post
– SLS Flight Software Safety Issues at MSFC (Update), earlier post
– Previous SLS postings
Not discussed above is the status of the mobile launcher upgrades. According to one piece of scuttlebutt I’ve seen, Block1b will require a completely new mobile launcher, which will be built from scratch! That is yet another reason for downgrading EM-2 to the Block1 vehicle. This would reduce the payload to just the crew, without many of the scientific instruments originally planned for that mission. If this and the software issue causes continued slippage, the crew might rendezvous with a Dragon2…launched from a SpaceX lunar base! Congress and NASA might just be better off to buy a lunar mission from SpaceX!
I asked that too before I read yours..
Why would SpaceX fly a Dragon2 from the Moon when they will have the BFR to fly? They are already building the fuel tanks for it and SpaceX just closed a deal on $500 million in new financing.
The SLS/Orion EM2 will be the Langley Flyer of space…
Speaking of BFR, sounds like it’s grown a bit (E2E = Earth to Earth transportation video)
https://twitter.com/VoltzCo…
Erik Cleven @VoltzCoreAudio
Replying to @elonmusk and 3 others
Has the BFR/BFS been stretched in height? The video Gwynne showed at Ted Talks looks taller than the one in the E2E video
https://twitter.com/elonmus…
Elon Musk ✔ @elonmusk
Maybe a little ?
3:09 AM – Apr 13, 2018
I was being facetious. Regardless of what SpaceX would actually use, by the time SLS/Orion actually flies any of the commercial companies could actually be ON the Moon. For that matter, it could be Wiley E. Coyote’s Acme space ship. 😉
“Langley Aerodrome” not “Flyer.” I know the meaning of the term has changed, but that’s what he used “aerodrome” to mean. Actually, I think he invented the term. And Glenn Curtiss did modify it and get it to fly in 1914. If SLS is a flop, I don’t expect anyone fixing it up and flying one in around 2040, just to prove it could have worked.
Yes, I was writing from memory. Orville Wright was so upset he sent the Wright Flyer to England to a museum. It didn’t return to the US until after WWII.
Probably not, but only because of the cost of it. ?
“And then, of course, there is the issue of flying probes to Europa on SLS – a task Congress has put on NASA’s agenda. The whole idea behind using SLS was to get there faster.”
A cynic might say that the whole idea behind getting there faster was to use SLS.
As far as I know it’s not been demonstrated that SLS will achieve Jupiter faster than BFR.
And to those who point to the ‘paper’ quality of BFR, I’d agree; but SX does have a track record of bringing gigantic rockets to the launch pad at agreeable costs (and often lengthy delays, but still).
“Falcon Heavy becomes exceptionally competitive if that option comes forward.”
Time for someone to run a hard crunch of the numbers of how long it will take Block 1 to get EC to Jupiter, and then compare that to Falcon Heavy. All I’ve seen are Block 1B calculations.
Of course, even that would only by the Falcon Heavy as it exists now. We don’t know what the performance improvements will be once it moves to Block 5.
Dr. Crary: Wasn’t it you that discussed in very broad terms the time and trajectory for the two boosters on an EC mission in these pages at some point?
That was me, and I just checked again. The idea of a Falcon Heavy raises an interesting new possibility. (Although that is not something the Europa Clipper project has discussed in public, to the best of my knowledge.)
For a direct trajectory to Jupiter (with a bit under three cruise), I think it would have to be a SLS Block 1B. That’s the current baseline, and I’ve heard discussions of this being a tight fit (specifically so tight that no significant secondary payloads were on the table.) That takes a C3 of over 70 km^2/s^2 (i.e. moving sqrt(70) or over 8 km/s relative the the Earth after escaping Earth’s gravity.) I don’t have numbers for a SLS Block 1, but I’m pretty sure it wouldn’t be able to put Clipper on a direct trajectory. That means you’d need gravity assists and a long cruise, and then there isn’t much point using SLS.
The planned alternative is a Atlas V 551. That would require a six or seven year trip with Earth and Venus flybys. The idea of a Venus flyby is inconvenient, since it really complicates the thermal design. That only takes a C3 of about 15 km^2/s^2 (~4 km/s after escaping Earth’s gravity.)
Another option, which hasn’t been discussed to the best of my knowledge, is a five-year cruise using a large deep space maneuver (~900 m/s) and a single Earth flyby. That’s the trajectory Juno used, and has also shown up in some unselected New Frontiers and/or Discovery proposals. Since Earth and Jupiter are the only planets involves it repeats every 13 months. That means you could slip the launch date without having to redesign the whole cruise. This requires a C3 of about 30 km^2/s^2 (a bit over 5 km/s after escaping Earth’s gravity.)
A Delta IV Heavy could do that, but a Delta IV Heavy is very expensive. I guess no one thought the benefits were worth it, compared to the slightly longer and less convenient trajectory an Atlas V 551 could use.
_But_ it looks like a fully expended Falcon Heavy could also do it. That’s got several advantages over the current Atlas option. An important question is how many successful launches NASA would want before baselining for use on a flagship mission, and when Falcon Heavy would have that track record. That could be too late in Clipper’s development schedule.
Very helpful analysis here. Much obliged.
A fully expendable Falcon Heavy is about $150M according to Elon Musk on twitter. Which cost less than the Atlas V 551 option.
There is a thread on the NSF forum about the Europa Clipper along with the various launch options and flight paths.
Thanks.
And of course now there’s BFR in the mix as well.
I don’t think BFR will matter for Europa Clipper. If I understand it correctly (and the document I looked at had some inconsistencies in it), NASA would want six successful flights, and at least three of them consecutive, before it would fly a flagship mission on a new launch vehicle. Yes, I know they aren’t applying that standard to SLS, but they also aren’t holding SLS/Orion to the same standards as the Falcon 9/Dragon 2 or Atlas/CST-100, when it comes to flying astronauts.
In terms of schedule, Clipper probably needs to fix the choice of a launch vehicle before the Critical Design Review. That’s November of next year. I suppose they could hold off to the end of phase C, at the end of 2020, but I don’t think they can wait any longer than that. I know Mr. Musk has always come through eventually, but his record for being on time isn’t great. And even on the Big Rock Candy Mountain, I doubt BFR will fly to orbit six times in the next three years (less time for NASA to do the certification paperwork.)
I’d include Delta IV Heavy in that comparison as well. It’s more expensive than Falcon Heavy, but it’s still about $ billion cheaper than an SLS launch!
if they launch the second SLS in 2023 and it is a block 1 .. they will still be looking at a 33 month delay to rebuild the pad for the block 1b?
Wrong. The senate graciously funded a new launch platform for the Block 1B. So there is no delay to modified the current launch paltform with the leaning tower.
Of course there is the small matter of the EUS stage getting developed and build on time. Don’t hold your breath waiting.
Yes. Wayne Hale predicts 4-5 more years to develop and build EUS in that Arstechnica piece. I suspect he’s being charitable.
Then too, there’s the question of whether they can bring the second launch tower online on time & budget even as a new start. The first one currently looks like taking eight years and 700 million dollars to first SLS flight.
But you must remember, it’s prime mission is to keep $3-4 billion a year flowing to the NASA Centers and Contractors. Sounds like it will be successfully achieving that mission for decades into the future 🙂
That’s SLS/Orion as a system, of course. Individual elements may cost somewhat less…
You just love downing any and everyone who works for the government….
Too bad we can’t pound sense into NASA and Congress that at least some of the NASA centers and NASA contractors (aka NASA design bureaus…like the Russian design bureaus) that they could be “privatized” without too much heartburn. After all, back in the Old Days, when two contractors competed for a gub’mint contract, at least some of the engineers and techs at the loser packed up our sliderules and hardhats in the station wagon and headed down the road to the winner’s town. In some cases, we were even able to stay in the same locale!
JWB (retired member of Aerospace Gypsies (ret)), 1960’s through 1989)
P.S. They ought to change the name of SLS EM-n to “BD-1” (BD=boon doggle) :rolleyes:
So the Block 1B variant is in a race with the BFR, the revised New Glenn, the Vulcan ACES and the new Liberty concept NGL from O-ATK to see who is last to enter service.
In the mean time. The unflown Block 1 only got marginally more performance than the already flown Falcon Heavy prototype with F9 block 3 and block 4 cores. Just about 20x more expensive than a Falcon Heavy expending center core for roughly same lift performance. The iCPS derived from the Delta IV DCSS is simply too small to delivered the delta-V needed.
Time to cancel the SLS/Orion money pit. They couldn’t even do the SLS make-work LOP-G build up without commercial launchers to supplement the in-frequent SLS flights. All the LOP-G components can fly up with commercial launchers.
I suspect Europa Clipper better plan on a lift from FH or, maybe, SLS Block 1. And I also suspect we’re about to get a $1B Block 1B mobile launcher that will never launch anything.
EUS has had a couple of obvious problems baked into the cake for a while now.
One is NASA’s HSF’s system development culture tendency to inflate any significant project to double-digit years and billions both, absent powerful external constraints. (This is also an albatross around the neck of any potential lander development.) (NASA has btw actually shown signs of thinking about solutions to this in the lander context – see Gerstenmaier’s panel at the recent Goddard Symposium.)
Then there’s the decision to buy a clean-sheet EUS from Boeing (with little recent hydrogen experience) rather than contract for a custom ACES variant from ULA (which has lots.)
Add in the launch-tower issues, and this decision strikes me as bowing to the inevitable. It does resolve at least one major near term issue.
For me, at least, the idea of building another $500M crawler is the last straw. It is beyond inept.
At what point do we just laugh out loud?
Some of us have been laughing (crying hurts too much) since before SLS, when Ares 1 and 5 still proudly roamed the land trampling the remains of “spiral development” into the dust.
Actually, longer than that.
Seriously. The agency’s development culture problems were readily visible by the late eighties, for those inclined to look closely into the matter.
Admittedly, it took a certain pigheaded conviction that “we have got to be able to – and we must! – do better than this” plus flagrant disregard for personal career development to so look.
Yeah well, that’s history. Now that the problem is obvious, there’s still the minor matter of usefully solving it within real-world political/institutional/budgetary constraints.
Lots of heavy lifting still ahead – but at the end, there’s hope of space finally happening the way we dreamed when we were young.
“space finally happening the way we dreamed”
My dream rockets had NASA proudly emblazoned on them. Turns out it’s going to be SpaceX.
SpaceX on the rockets is better than it not happening at all.
But the real question is not the need for another crawler. The question is :Why does it cost $500 million?
I expect the Vulcan launcher’s Centaur V stage to become the SLS upper stage now. It will have less propellant than the proposed EUS, yes. But it has 3x the propellant of a Delta IV-Heavy’s upper stage being used for Block 1 SLS, has about the same thrust as the EUS, has multiple restart capability and is ALREADY a couple of years into full development. The EUS will take years more and BILLIONS to come into being. Yes; the Centaur V will have less performance than the EUS. But it should still enable at least a 20 ton payload improvement over the Delta Interim upper stage and be quicker and much cheaper to develop.
If the SLS Block 1B goes to Centaur V – and maybe eventually ACES – years and billions could be shaved off the SLS development and operational implementation. If using the ‘weaker’ stage causes any performance hits to SLS; improvements to the corestage RS-25 engines, changing the corestage to a lighter aluminum/lithium alloy and the advanced strap-on boosters supposedly in the development pipeline should more than make up for it.
The Vulcan Centaur V will be less capable than the revised New Glenn with dual BE-3U second stage plus optional mono BE-3U third stage that will be available in the same time scale.
Don’t see either the Centaur V or the New Glenn second stage being used on the SLS.
The Centaur V will not get modified for the SLS without the USAF’s approval, which will not be fore coming like the saga of the attempt to man-rated the Delta IV Heavy.
Jeff Bezos will not have anything to do with the SLS when he is developing the New Armstrong.
I predict there will be only one operational SLS variant in the form of the Block 1.
You’re probably right. Though I never intended to imply that any stage other than the Centaur V would be the substitute. Either the Delta IV ICPS will continue to be used – with or without further mods – or the deletion of the Exploration Upper Stage will be the first in a ‘death of a thousand cuts’ for the SLS project as a whole…