[New] Space Launch System / Orion Discussion Thread

[RCgothic]

2 hours ago, tater said:

Useful thing to pop up today:

 

 

[tater]

Minus SLS costs, that number is really high for Orion. Even lowballing SLS at the imaginary 900M$ value would add 225M$/seat. So that's a minimum of 516 million per seat assuming SLS launch. The 291M$ figure is useful for comparing architectures with NG as the LV, though.

[RCgothic]

Orion costs.

Average is $1.35B per year to 2025.

By 2030 at this rate, 10 flights for it will be $3.3B just for Orion and the ESM.

This is truly ridiculous. Add SLS to Orion, and even if they survive 10 flights that's over $6.5B per flight.

 

Commercial crew on the other hand has paid $8.4B for 17 flights ($500m per flight) AND arguably developed three full spacecraft (Starliner, Dreamchaser, Dragon2) and crew-rated Falcon 9.

Edited May 19, 2020 by RCgothic

[tater]

3 minutes ago, RCgothic said:

Orion costs.

Average is $1.35B per year to 2025.

By 2030 at this rate, 10 flights for it will be $3.3B just for Orion and the ESM.

This is truly ridiculous. Add SLS to Orion, and even if they survive 10 flights that's over $6.5B per flight.

 

Commercial crew on the other hand has paid $8.4B for 17 flights ($500m per flight) AND arguably developed three full spacecraft (Starliner, Dreamchaser, Dragon2) and crew-rated Falcon 9.

The ESM is an in-kind contribution, and  has zero cost, too. Since it's paid for with astronaut seats, it might be fair to divide the cost by 3 seats from a NASA POV (depends on how many seats ESA gets, obviously).

 

[StrandedonEarth]

Ya know, considering what a capable beast it was, the dev cost for the Shuttle Orbiter was quite reasonable. And we got a lot of use out of those birds. I won't get into operational cost or design flaws....

As for the whole SLS pro/con/capability debate, All I have to say is that huge rockets are nice to watch. But there likely won't be many huge rockets if the price tag is equally huge,  because it makes such a juicy target for budget cuts if used by gov't, and commercial entities will balk at too high a price (looking at you, Saturn V, you big beautiful beast you).

Talking about all these huge rockets and massively powerful engines brings out the Tim Taylor in me...

 

Edited May 20, 2020 by StrandedonEarth

[tater]

11 minutes ago, StrandedonEarth said:

As for the whole SLS pro/con/capability debate, All I have to say is that huge rockets are nice to watch. But there likely won't be many huge rockets if the price tag is equally huge,  because it makes such a juicy target for budget cuts if used by gov't, and commercial entities will balk at too high a price (looking at you, Saturn V, you big beautiful beast you).

The big issue with huge cost LVs is that if the LV is super expensive, the payload needs to be considerably MORE expensive.

Curiosity cost what, ~2.5B$? It flew on an Atlas V 551. That's 153M$ in launch costs, nominally, so the payload cost ~16X the launch cost.

Got any (does math), 32 billion dollar payloads? Oh, sorry, that was calling an SLS launch 2B$. Let's use 900M, got any 14.75B$ payloads?

If we use the same math for a FHe launch, that's 2.46B$ payloads... like Curiosity.

[mikegarrison]

4 hours ago, StrandedonEarth said:

Ya know, considering what a capable beast it was, the dev cost for the Shuttle Orbiter was quite reasonable. And we got a lot of use out of those birds. I won't get into operational cost or design flaws....

People in this forum seem to ignore the fact that the Shuttle was basically an entire space station that was launched every time -- often also with a satellite at the same time. Comparing it to the cost of launching a capsule is very misleading, except in the context of saying, "Now that we have the ISS, we don't have to launch the whole station every time."

Edited May 20, 2020 by mikegarrison

[tater]

17 minutes ago, mikegarrison said:

People in this forum seem to ignore the fact that the Shuttle was basically an entire space station that was launched every time -- often also with a satellite at the same time. Comparing it to the cost of launching a capsule is very misleading, except in the context of saying, "Now that we have the ISS, we don't have to launch the whole station every time."

I still think a Shuttle Derived HLV would have been useful. The side mount version so that it could use existing Shuttle infrastructure. Was a ~7.5m payload diameter, and something on the order of 80t to LEO. Expendable, but could have allowed even cislunar missions staged from ISS.

Spoiler

 

[kerbiloid]

Inho, the engine part could/should be made reusable.

[Shpaget]

Not exactly SLS related, but...

Doug Loverro, NASA's head honcho for human spacefligh, resigned. Ken Bowersox to take the seat, at least until permanent replacement is found.

https://www.nasaspaceflight.com/2020/05/loverro-resigns-bowersox-acting-heo-lead/

[sevenperforce]

9 hours ago, kerbiloid said:

Inho, the engine part could/should be made reusable.

They could have dropped off the used SSMEs at the ISS and used a Canadarm to mount the SSMEs inside an empty Shuttle bay once every dozen missions or so. Logistical nightmare though.

[sh1pman]

6 hours ago, sevenperforce said:

They could have dropped off the used SSMEs at the ISS and used a Canadarm to mount the SSMEs inside an empty Shuttle bay once every dozen missions or so. Logistical nightmare though.

Can you burn to TLI from ISS orbit without an insane inclination change maneuver? 

[Codraroll]

32 minutes ago, sh1pman said:

Can you burn to TLI from ISS orbit without an insane inclination change maneuver? 

Solution: build a second space station orbiting in the plane of the TLI maneuver (assuming such a thing exists). After all, in this scenatio we've re-introduced the shuttles used to build it already.

Edited May 20, 2020 by Codraroll

[tater]

Depends on the target orbit what the expense is dv wise. It;s largely a phasing issue. Burn at a node. Given NRHO this might not allow many launch opportunities—what are the launch opportunities for Gateway, actually? They'll want a fast transfer, so they have to hit not just the plane, but the right timing to minimize phasing once they are in NRHO, as well.

[sevenperforce]

4 hours ago, sh1pman said:

Can you burn to TLI from ISS orbit without an insane inclination change maneuver? 

Yes, easily. When you're going cislunar, inclination really doesn't matter at all. You don't have to change inclination because you can predetermine your flyby to do literally any plane change, completely free. There's a phasing issue at high inclinations but it's not serious.

ISS altitude is a little more dV-costly for TLI than a super-low parking orbit but not so much that an apogee dive is worth it.

[tater]

 

[mikegarrison]

14 hours ago, sevenperforce said:

Yes, easily. When you're going cislunar, inclination really doesn't matter at all.

Does that include consideration of avoiding the high-radiation parts of the Van Allen belts?

[sevenperforce]

1 hour ago, mikegarrison said:

Does that include consideration of avoiding the high-radiation parts of the Van Allen belts?

You don't need to avoid the Van Allen belts. Most Apollo missions went around them, but Apollo 14 went straight through with no ill effects.

The VA belts are inclined at 11.4 degrees, the Cape is inclined at 23 degrees, the ISS is inclined at 52 degrees, and the moon is at 5 degrees, so it is actually pretty hard to hit the inner belts at all when launching from the Cape, and extremely hard from the ISS.

The way you control your insertion inclination at the moon actually depends on the argument of periapsis you give to your trans-lunar injection. Whether you're burning from a Cape-launched parking orbit or burning from the ISS, you'd still perform your TLI roughly from the point along the line of intersection between your orbital plane and the moon's. But timing is key. If you are doing a classic figure-8 free-return, aiming just ahead of where the moon will be (as opposed to just behind, which would slingshot you to Earth escape), your parking orbit inclination will be reversed during your flyby. If you burn just before your ascending node, your Hohmann will have an apogee that is slightly above the plane of the moon's orbit and thus your flyby will be at a higher latitude than it otherwise would have been, bending your lunar orbit more toward polar. If you burn just after your ascending node, you will pass low and so the reverse will be true. 

Edited May 21, 2020 by sevenperforce

[mikegarrison]

Apollo 14 did take quite a bit more radiation than the others. Seems like avoiding radiation exposure when reasonably possible is smarter than just ignoring it, even when it's not strictly *necessary* to avoid it.

[tater]

7 minutes ago, mikegarrison said:

Apollo 14 did take quite a bit more radiation than the others. Seems like avoiding radiation exposure when reasonably possible is smarter than just ignoring it, even when it's not strictly *necessary* to avoid it.

Well, the pro-Gateway people seem to think that irradiating the astronauts is the point. Or something

(since the only thing that we really learn in a distant lunar orbit is what happens to astronauts in that radiation environment)

 

[sevenperforce]

14 minutes ago, mikegarrison said:

Apollo 14 did take quite a bit more radiation than the others. Seems like avoiding radiation exposure when reasonably possible is smarter than just ignoring it, even when it's not strictly *necessary* to avoid it.

Unless you are in a parking orbit aligned with the moon's orbital plane, then there are only ever two choices for your TLI burn: the ascending node and the descending node. Those only line up with the moon's actual position twice a month. So avoiding radiation is just a matter of looking at your precise planned trajectory and asking "Is this one of those 1-in-20 times when we run smack dab into the belts? Oh, it is? Okay, let's go two weeks later." 

[Space Nerd]

 

14 hours ago, tater said:

Well, the pro-Gateway people seem to think that irradiating the astronauts is the point. Or something

(since the only thing that we really learn in a distant lunar orbit is what happens to astronauts in that radiation environment)

Nope, I know gateway has these flaws but I still think it's cool.

How does the radiation strength in NRHO compare to that in the Van Allen belts and interplanetary space/around mars? (Isn't the moon usually in the earth's magnetic field?)

I still think high lunar orbit is a good place to learn about deep space habitation, since the challenge there is quite different from LEO.

 

Edited May 22, 2020 by Space Nerd

[tater]

3 hours ago, Space Nerd said:

 

Nope, I know gateway has these flaws but I still think it's cool.

How does the radiation strength in NRHO compare to that in the Van Allen belts and interplanetary space/around mars? (Isn't the moon usually in the earth's magnetic field?)

I still think high lunar orbit is a good place to learn about deep space habitation, since the challenge there is quite different from LEO.

 

Understanding that environment is indeed important for human spaceflight, but doing so with humans isn't really the way you do detrimental experiments from a medical ethics standpoint. We can measure radiation, in short, no need to expose people to it needlessly. Doing so incidentally while doing something more interesting is less of a problem. The real plus of Gateway, the only plus, IMO, is that it's an anchor that keeps a program around to go to "not LEO." The only place that's actually interesting near Gateway is the lunar surface, in short, and having an asset out there with international partners makes continuing operations slightly more likely, even if there's nothing to do AT the Gateway.

[Space Nerd]

I don't mean exposing astronauts to radiation is the point of gateway(I think it should have more radiation protaction), it's a place to pratice living in space where any resuply or rescue is at least 3 days away, while is far from 1~2 years of a mars mission, but I think it is a good practice before a mars mission.

[tater]

27 minutes ago, Space Nerd said:

I don't mean exposing astronauts to radiation is the point of gateway(I think it should have more radiation protaction), it's a place to pratice living in space where any resuply or rescue is at least 3 days away, while is far from 1~2 years of a mars mission, but I think it is a good practice before a mars mission.

I'm not sure why being far from home is a good plan. What if there is a problem, then it's better to have an increased chance of death, just because? The could design a habitat for long term use, say a Mars transit time. Put it in LEO. Send up astronauts, and have them fly that mission in LEO, no resupply. If there is a problem, then they come home.

The primary benefit of the cislunar region probably relates to spacecraft temperature regulation studies since it's a more constant environment than LEO day/night cycles (and light reflection from Earth), so there is some real utility there, I suppose.