[New] Space Launch System / Orion Discussion Thread

[sevenperforce]

1 hour ago, RCgothic said:

Slipping towards March 2022 then.

Wow. It looks like SLS may never be the largest operating launch vehicle, if Elon can do an all-up Starship flight by the end of this year.

[Clamp-o-Tron]

7 minutes ago, YNM said:

So... a waste of a full set of SRBs ?

IIRC they’re only limited in shelf-life when combined, all of these segments are from the shuttle era. I would expect de-stacking to begin soon.

[tater]

1 hour ago, YNM said:

So... a waste of a full set of SRBs ?

They have  a shelf life once stacked, but I'm sure that has margin. They will certainly decide that the SRBs are within useful spec and use them I would guess (though it's bizarre they didn't wait for Green Run before stacking them).

[RCgothic]

They think that a year may not be a hard limit. They'll find a way to recertify them for flight.

[StrandedonEarth]

 

[mikegarrison]

This "longstanding policy" is pretty much imaginary.

18 minutes ago, StrandedonEarth said:

 

 

[tater]

Just now, mikegarrison said:

This "longstanding policy" is pretty much imaginary.

And doesn't apply to SLS in any case—if private companies were launching commercial ventures to the Moon, and SLS was selling trips to the Moon... they'd be in competition. SLS isn't selling anything, so they can't be in competition.

Berger's quote is more interesting than the rando reply.

[StrandedonEarth]

Well

5 minutes ago, tater said:

rando reply.

Well, there was another rando reply...

Spoiler

 

 

[Clamp-o-Tron]

Not to mention that SLS is the only rocket that can launch the only BLEO crewed  spacecraft to a useful orbit. 

Waiting for Starship to become crew-rated (~ 10 years) is hairbrained, as are the commercial “replacements” on Falcon Heavy / Delta IV Heavy that require deceptively large amounts of development when SLS is ready for use save a few logistical delays.

[Scotius]

2 minutes ago, Clamp-o-Tron said:

Not to mention that SLS is the only rocket that can launch the only BLEO crewed  spacecraft to a useful orbit. 

Waiting for Starship to become crew-rated (~ 10 years) is hairbrained, as are the commercial “replacements” on Falcon Heavy / Delta IV Heavy that require deceptively large amounts of development when SLS is ready could be ready for use save a few logistical delays.

Fixed it for ya

[Clamp-o-Tron]

1 minute ago, Scotius said:

Fixed it for ya

It’s a minute difference. What more could go wrong, technologically, to prevent Artemis-1 launch within the internal (IIRC Jan 2022) calendar? The problem with the engines that presented itself at GR-8 is of no importance to a flight, and the LOX valve issue should be fixed any day now. (On a related note, an RS-25 engineer I’ve talked to mentioned another small problem with the LH2 manifold [again, IIRC] which was fixed on the stand and was of no detriment to the engines.)

[tater]

9 minutes ago, Clamp-o-Tron said:

Not to mention that SLS is the only rocket that can launch the only BLEO crewed  spacecraft to a useful orbit. 

It can send people to BLEO, but it cannot put them in a useful orbit. At least not if they want to come home.

NRHO is a useless orbit. The only reason to be near the Moon with humans, is to land on it. Any humans in NRHO then need to be brought to a useful orbit from which to land.

Of course all that is contingent on SLS and Orion actually flying.

SLS likely flies in early(ish) 2022. Orion will not fly "all up" until the next flight, or indeed maybe the third (the first crew mission has no docking equipment, right?).

9 minutes ago, Clamp-o-Tron said:

Waiting for Starship to become crew-rated (~ 10 years) is hairbrained, as are the commercial “replacements” on Falcon Heavy / Delta IV Heavy that require deceptively large amounts of development when SLS is ready for use save a few logistical delays.

SS need not be "crew rated" per NASA. They can simply fly it, and let NASA decide after the fact (they fly on Soyuz without having the data required to crew rate it the way they have for their own vehicles).

5 minutes ago, Clamp-o-Tron said:

It’s a minute difference. What more could go wrong, technologically, to prevent Artemis-1 launch within the internal (IIRC Jan 2022) calendar? The problem with the engines that presented itself at GR-8 is of no importance to a flight, and the LOX valve issue should be fixed any day now. (On a related note, an RS-25 engineer I’ve talked to mentioned another small problem with the LH2 manifold [again, IIRC] which was fixed on the stand and was of no detriment to the engines.)

I think they are on track for NET Feb 2022, which almost certainly means March—they have zero schedule margin, literally any delay is day for day, hurricanes, etc, not to mention the launch window, all launches from FL have a decent chance at delay from weather.

Regardless, we have no idea when the first all-up SLS/Orion will fly, cause Artemis I ain't it.

[mikegarrison]

I think the root cause of the SLS problems is pretty much the same root cause of the problems with the Space Shuttle. The government was not willing (or probably able) to spend the kind of money they spent during the Apollo years, and so everything got stretched out. First of all, that just makes it more expensive all by itself. But secondly, it meant they had too much time for mission creep to change the mission after they had already locked in parts of the design. And then they tried to work around the locked-in designs, and that leads to more costs. And then the mission changes again. And now they have even more locked-in design to work around. Lather, Rinse, Repeat.

They are using bits from the Space Shuttle, bits from Aries, bits from here, and bits from there. At some point the primary goal became to find a mission that could use the SLS and Orion, so that all those sunk costs didn't just sink.

In a sense, yes, it's because government. Because every four or eight years a new team came in with a new goal. Because they don't have the kind of 10-year committed funding that Apollo had, but instead have to get their budget reauthorized every two years. But it's not because this is government trying to mess around where it should be private enterprise. First of all, "old space" was mostly private enterprise anyway, working for government contracts. And secondly, much of "new space" is the same thing -- private enterprise working for government contracts.

I think the big problem really is that it's a rocket program looking for a mission, rather than the other way around.

[RCgothic]

1 minute ago, mikegarrison said:

I think the root cause of the SLS problems is pretty much the same root cause of the problems with the Space Shuttle. The government was not willing (or probably able) to spend the kind of money they spent during the Apollo years, and so everything got stretched out. First of all, that just makes it more expensive all by itself. But secondly, it meant they had too much time for mission creep to change the mission after they had already locked in parts of the design. And then they tried to work around the locked-in designs, and that leads to more costs. And then the mission changes again. And now they have even more locked-in design to work around. Lather, Rinse, Repeat.

They are using bits from the Space Shuttle, bits from Aries, bits from here, and bits from there. At some point the primary goal became to find a mission that could use the SLS and Orion, so that all those sunk costs didn't just sink.

In a sense, yes, it's because government. Because every four or eight years a new team came in with a new goal. Because they don't have the kind of 10-year committed funding that Apollo had, but instead have to get their budget reauthorized every two years. But it's not because this is government trying to mess around where it should be private enterprise. First of all, "old space" was mostly private enterprise anyway, working for government contracts. And secondly, much of "new space" is the same thing -- private enterprise working for government contracts.

I think the big problem really is that it's a rocket program looking for a mission, rather than the other way around.

I agree, although not all capabilities get screwed by mission changes.

It would have been possible to go with a more flexible architecture better able to cope with mission changes. I think it would be hard to go wrong by optimising 2-stage to LEO with an optional 3rd stage for earth departure, for instance.

But then politically if a rocket is capable of a changing mission, perhaps that would have put the lunar program at risk of cancellation yet again (although in that case at least the rocket would survive the death of the program for to its universal usefulness).

I'm a little bit split on whether large rockets should yet be the domain of fixed price contacts, but certainly this plus cost contact doesn't seem to have worked very well.

[tater]

4 hours ago, mikegarrison said:

I think the big problem really is that it's a rocket program looking for a mission, rather than the other way around.

This.

The lack of mission has always been the problem with SLS. Constellation had a place to go—the Moon—but rockets designed to meet that goal they could not get to work.

SLS is just the opposite, they have a rocket that will very likely work—but no place for it to go.

Edited March 3, 2021 by tater

[sevenperforce]

11 hours ago, Clamp-o-Tron said:

SLS is the only rocket that can launch the only BLEO crewed  spacecraft to a useful orbit. 

The orbit to which SLS can presently send Orion is precisely as useful as the orbit to which Delta IV Heavy sent Orion.

Which is, to say, not at all. 

11 hours ago, Clamp-o-Tron said:

...the commercial “replacements” on Falcon Heavy / Delta IV Heavy that require deceptively large amounts of development when SLS is ready for use...

And what is SLS ready to be used for? Launching an all-up lunar surface sortie? Oh, wait, it doesn't have the capacity to do that. Launching a moon lander? Oh, wait, it doesn't have the launch cadence to do that.

For SLS to do anything useful, it needs to be supported by commercial "replacements" to do everything it can't do. Which means we need to tackle those "deceptively large amounts of development" with or without SLS.

The amount of "development" required to make SLS useful is arguably less than the amount of "development" it would take to order an expendable Starship to assume the role of the Ares V in a Constellation-style mission architecture. You could even slap Orion on top; there's plenty of margin. Don't bother man-rating it; just send crew up in Dragon.

[Guest]

It feels like that SLS get's a lot more hate than praise. SLS is actually really good and really cool and there is a reason why people are still excited for it. Most of the reasons why people say SLS sucks is because they say there is Starship or it has no purpose (which is kinda true there isn't that many purposes for this rocket). But Starship as of right now is a dangerous rocket and is very innovative. Starship is in a current state where they will need a lot of flights to prove the concept. It's too dangerous for crew right now. SLS is doing a proven concept, a capsule on an expendable rocket is extremely safe right now. And right now, it makes more sense to send crew on SLS than on Starship. SLS is using the slow and steady method. Currently, there is no better alternative to SLS. SLS is also the most inexpensive rocket NASA has developed yet.

 

So maybe instead of hating SLS maybe we should be excited we have the capability to send crew to the Moon. Starship isn't ready for crew yet and won't be ready for years.

Edited March 3, 2021 by Guest

[wumpus]

6 hours ago, mikegarrison said:

I think the root cause of the SLS problems is pretty much the same root cause of the problems with the Space Shuttle. The government was not willing (or probably able) to spend the kind of money they spent during the Apollo years, and so everything got stretched out. First of all, that just makes it more expensive all by itself. But secondly, it meant they had too much time for mission creep to change the mission after they had already locked in parts of the design. And then they tried to work around the locked-in designs, and that leads to more costs. And then the mission changes again. And now they have even more locked-in design to work around. Lather, Rinse, Repeat.

Both the Shuttle and the SLS have been excellent at obtaining money from Congress and are wildly successful from the perspective of a NASA employee's career (or contractor with a more or less "permanent" job that has revolving employers and the same job.  They tend to outnumber "official" employees).  This lead to the Shuttle performing something like 200 crewed missions, and certainly keeping the USA out in space.  While it to was something of a "rocket to nowhere" when they cut the other 3/4 of the STS program, the fact that it provided a useful area for the crew made it effective by itself.  It doesn't appear that SLS has a chance to match this record, but keep in mind that NASA employees presumably want to keep their jobs and like programs that aren't cut.

PS: It looks like New Glenn is also on schedule to launch near SLS's expected launch time.  Is it bigger as well?

[RealKerbal3x]

SLS is a rocket designed with no specific mission in mind - overpowered for LEO operations, underpowered for beyond LEO. It's not powerful enough to get Orion to low lunar orbit, leaving landers to spend extra dV flying between a distant elliptical orbit and the surface. The entire program has been addled by delays and cost overruns (it was legally required to fly in 2016).

And it's not really the only option. Seeing as SpaceX is already designing a variant of Starship to land crew on the Moon, why not just cut SLS out entirely and send crew to and from LEO aboard Dragon/Starliner? With orbital refuelling and maybe some light aerobraking it could probably be done.

[cubinator]

The rocket isn't what I dislike about SLS. It's the convoluted management that prioritizes politics over missions. NASA hasn't been allowed to go through with actual lunar plans for a long time. By the time SLS is operational, multiple alternatives will be available for a tenth or a hundredth of the cost.

12 minutes ago, The Doodling Astronaut said:

SLS is also the most inexpensive rocket NASA has developed yet.

That sounds untrue. I'm pretty sure SLS is more expensive than Saturn V.

[tater]

15 minutes ago, The Doodling Astronaut said:

Most of the reasons why people say SLS sucks is because they say there is Starship.

This is untrue.

I have said SLS sucks since the beginning because it has always been a "rocket to nowhere."

Saddled with Orion—as it has been from the start—it is completely incapable of useful BLEO missions, and it can never be made capable as long as Orion is the payload. Something has to go. Make a smaller spacecraft, and an updated SLS (Block 2) could do useful missions.

 

1 minute ago, cubinator said:

That sounds untrue. I'm pretty sure SLS is more expensive than Saturn V.

Not in constant dollars.

That said, being cheaper makes no difference. Dollars per capability is what matters.

Say I could buy 2 expensive cars. One is $100,000, and does everything I need a car to do. The other costs only $75,000, but it can't even make a round trip to the grocery store. Which car is more sensible to buy, if you must pick one?

[sevenperforce]

18 minutes ago, tater said:

19 minutes ago, cubinator said:

36 minutes ago, The Doodling Astronaut said:

SLS is also the most inexpensive rocket NASA has developed yet.

That sounds untrue. I'm pretty sure SLS is more expensive than Saturn V.

Not in constant dollars.

I mean, it depends on your math. The total cost of the Apollo program in real dollars was $283 billion. That got us six moon landings for a cost of $47 billion per mission.

But of course SLS has not gotten us any moon landings, nor will it for some time. Nor will its first launch be crewed. Apollo had a total of twelve Saturn V launches (thirteen if you count Skylab, which you should because this is about rocket development). And a lot of that $283 billion had more to do with the lunar sorties themselves; development cost and launch vehicle cost came to $125.5 billion (and that includes the cost of the Saturn 1Bs which I'm not counting in the total number of launches). So that's $9.7b per rocket.

As of 2020, total project cost has reached $18.6 billion, and we haven't even gotten a single launch out of it. We spend an average of $2.5 billion per year on it regardless of whether it flies, so by the time Artemis 1 launches (next year, realistically) it will have given us one uncrewed launch at a pricetag of $21 billion. By the time Artemis 2 launches in 2023 (if we're lucky) the total project cost will be at $26 billion, which at least lowers the per-launch cost to $13b. If Artemis 3 actually manages to launch at the end of 2024 (which is highly doubtful) then our total per-launch price will finally get down to the same per-launch cost as the Saturn V.

And remember that the development costs I quoted for Apollo included all lunar mission development, too.

18 minutes ago, tater said:

That said, being cheaper makes no difference. Dollars per capability is what matters.

Agreed.

[sevenperforce]

50 minutes ago, wumpus said:

It looks like New Glenn is also on schedule to launch near SLS's expected launch time.  Is it bigger as well?

No, New Glenn is quite big but it is dwarfed by SLS and Starship.

[RCgothic]

It's basically optimised to send a specific spacraft to a specific orbit where that spacecraft can't do anything useful without help and SLS is not flexible enough to be used for other missions.

Most of its LEO mass is fuel, but it could put up about 40-50 tons... But there aren't any monolithic payloads that size. If the payload is fuel, then it's a very expensive and infrequent way to refuel something in LEO.

For BLEO, other than crew flights its lack of availability has seen it stripped of its one assigned cargo mission.

[tater]

18 minutes ago, sevenperforce said:

I mean, it depends on your math. The total cost of the Apollo program in real dollars was $283 billion. That got us six moon landings for a cost of $47 billion per mission.

But of course SLS has not gotten us any moon landings, nor will it for some time. Nor will its first launch be crewed. Apollo had a total of twelve Saturn V launches (thirteen if you count Skylab, which you should because this is about rocket development). And a lot of that $283 billion had more to do with the lunar sorties themselves; development cost and launch vehicle cost came to $125.5 billion (and that includes the cost of the Saturn 1Bs which I'm not counting in the total number of launches). So that's $9.7b per rocket.

As of 2020, total project cost has reached $18.6 billion, and we haven't even gotten a single launch out of it. We spend an average of $2.5 billion per year on it regardless of whether it flies, so by the time Artemis 1 launches (next year, realistically) it will have given us one uncrewed launch at a pricetag of $21 billion. By the time Artemis 2 launches in 2023 (if we're lucky) the total project cost will be at $26 billion, which at least lowers the per-launch cost to $13b. If Artemis 3 actually manages to launch at the end of 2024 (which is highly doubtful) then our total per-launch price will finally get down to the same per-launch cost as the Saturn V.

And remember that the development costs I quoted for Apollo included all lunar mission development, too.

I have seen SLS fans (apologists?) make the claim that it is actually a low dev cost for NASA. I was willing to accept that as plausible at least for the sake of argument—because it doesn't matter if that cost results in something that is incapable of useful missions.

The trouble was keeping a spacecraft that was explicitly designed for the Constellation mission architecture, and sticking it on top of what is in effect a variant of Ares V—a launch vehicle also designed explicitly for the Constellation mission—but not as a crew rated LV. Ares I to put Orion in LEO, and Ares V to put the Altair lander (that did the LOI burn as well) to TLI—with Orion attached already. Ares V was ~70t to TLI. Unremarkably, that's basically what any stack that includes Orion needs to send to TLI to do a lunar mission. That's the minimum requirement for SLS to be useful, IMO. ~65-70t to TLI.