[New] Space Launch System / Orion Discussion Thread

[tater]

 

[JoeSchmuckatelli]

Is the discoloration from reentry heating or exposure while in space? 

If reentry - is there some sort of low pressure vortex at work? 

[sevenperforce]

15 hours ago, JoeSchmuckatelli said:

Is the discoloration from reentry heating or exposure while in space? 

If reentry - is there some sort of low pressure vortex at work? 

The discoloration is from re-entry heating.

Why would there be a low pressure vortex?

The plasma stream coming from re-entry is hot enough that it radiates enough heat to torch the backshell, which is why the backshell also needs heat shielding. Not a lot, but some.

[JoeSchmuckatelli]

6 hours ago, sevenperforce said:

radiates enough heat to torch the backshell, which is why the backshell also needs heat shielding

That's the part - I envision the plasma fanning out and away from the inwardly angled lander surface and was trying to imagine what process would discolor it. 

[sevenperforce]

15 hours ago, JoeSchmuckatelli said:

22 hours ago, sevenperforce said:

radiates enough heat to torch the backshell, which is why the backshell also needs heat shielding

That's the part - I envision the plasma fanning out and away from the inwardly angled lander surface and was trying to imagine what process would discolor it. 

Yep!

Believe it or not, even the forward heat shield receives its primary thermal energy flux radiatively, not by direct contact. Heat shields are shaped in such a way as to push the shockwave away from the vehicle so that the superheated plasma never actually touches it. But avoiding direct contact doesn't avoid the radiative flux. That's why heat shield tiles are made of materials that also have a high blackbody radiative coefficient: so that they can radiate the heat back and away from the vehicle as fast as they receive it. 

[JoeSchmuckatelli]

4 minutes ago, sevenperforce said:

Yep!

Believe it or not, even the forward heat shield receives its primary thermal energy flux radiatively, not by direct contact. Heat shields are shaped in such a way as to push the shockwave away from the vehicle so that the superheated plasma never actually touches it. But avoiding direct contact doesn't avoid the radiative flux. That's why heat shield tiles are made of materials that also have a high blackbody radiative coefficient: so that they can radiate the heat back and away from the vehicle as fast as they receive it. 

Thanks!

FWIW - your answers are always worth reading!  Appreciate the time you put into this!

[sevenperforce]

4 hours ago, JoeSchmuckatelli said:

FWIW - your answers are always worth reading!  Appreciate the time you put into this!

I really appreciate that. This is somewhat of a passion of mine. The closest I get to embracing my physics undergrad since I decided to go the lawyer route.

[Entropian]

9 hours ago, sevenperforce said:

I really appreciate that

I'm here with Joe on this one - your answers are nearly always well thought-out, informative, and detailed in many ways.  It's really great when you take the time to answer interesting questions

[RCgothic]

Interesting.

Definitely interested in what they bid for these contracts.

 

[RCgothic]

Block 1B delayed to 2028.

 

[RCgothic]

This couldn't be stupider if they tried:

STS is already the system name for the space shuttle, so this is just going to cause confusion.

The whole Artemis/Orion/SLS naming has been a bin fire from the start.

[NFUN]

1 minute ago, RCgothic said:

This couldn't be stupider if they tried:

STS is already the system name for the space shuttle, so this is just going to cause confusion.

The whole Artemis/Orion/SLS naming has been a bin fire from the start.

They could've named it "Shuttle"

[tater]

56 minutes ago, RCgothic said:

STS is already the system name for the space shuttle, so this is just going to cause confusion.

I personally found "STS" during the Shuttle era to be confusing, since I thought of STS/IPP as this:

<shrug>

 

[Cuky]

18 hours ago, RCgothic said:

Block 1B delayed to 2028.

 

 

I'd be surprised if that is to be the last delay

[Codraroll]

2 hours ago, Cuky said:

I'd be surprised if that is to be the last delay

Remember the old adage of this industry: "Any announcement made of an event more than two years in the future might as well not have been made at all."

Or in other words, if it's more than two years away, it's entirely up in the air and subject to any change at any moment.

Edited March 14, 2023 by Codraroll

[tater]

So the SRB contract included Ares I, and the test article they fired before Artemis I, and the SRBs for the next 2 flights—and is $4.4B.

For 8 SRBs.

$550M each. So the boosters alone are $1.1B.

The RS-25s are harder to sort out. The $2.1B contract for the first 16 seems to give a value of $131M per engine, but then there is a continuing contract to 2029 that includes 24 new engines, and additional cost for the 11 of the first 16. Ignoring the initial engines, the contract is $150M/engine, not the $99M I have seen before. It might well be lower than that, in which case the first 16 are more than $131... In short, RS-25s are absurdly expensive.

So an SLS core has between $524M and $600M worth of engines on the bottom, and over a billion in boosters.

[tater]

 

[NFUN]

41 minutes ago, tater said:

So the SRB contract included Ares I, and the test article they fired before Artemis I, and the SRBs for the next 2 flights—and is $4.4B.

For 8 SRBs.

$550M each. So the boosters alone are $1.1B.

The RS-25s are harder to sort out. The $2.1B contract for the first 16 seems to give a value of $131M per engine, but then there is a continuing contract to 2029 that includes 24 new engines, and additional cost for the 11 of the first 16. Ignoring the initial engines, the contract is $150M/engine, not the $99M I have seen before. It might well be lower than that, in which case the first 16 are more than $131... In short, RS-25s are absurdly expensive.

So an SLS core has between $524M and $600M worth of engines on the bottom, and over a billion in boosters.

how do the srbs cost so much I don't understand

[StrandedonEarth]

21 minutes ago, NFUN said:

how do the srbs cost so much I don't understand

The difference between actual cost and amount billed goes into the “black budget” for top secret alien military research projects…

[Ultimate Steve]

5 hours ago, NFUN said:

how do the srbs cost so much I don't understand

In aerospace, cost does not have very much to do with raw material cost and technological maturity. It depends some, but other factors dominate.

I was going to say simplicity in there as well, but I now know better than to call the SLS SRBs simple. They are very complex, but in a different way from liquids.

There is far greater cost impact from the following, in no particular order:

• Economies of scale (small production rates = high costs)
• Handling costs (Moving a giant explosive skyscraper around land and sea is not cheap)
• Facility costs (Have to build buildings safe enough for your explosive skyscrapers) (Have to build and upgrade launch facilities for your explosive skyscrapers)
• Regulatory costs (Have to prove your buildings and transportation architecture are safe enough to parade your explosive skyscrapers through populated areas)
• Employee costs (More employees is more expensive, more experienced employees are more expensive, and if you don't have the wow factor attracting employees for less, that's expensive)
  • All that infrastructure has employee costs too, for maintenance and stuff
• Effective use of time (If you have 1000 employees and some finite amount of work, it can either take a year or ten years depending on how good your employees are and how well their time is utilized) (And then you are paying 10x much in salaries for the same product)
• Any number of other factors

"Solids are simple and cheap!" is the simplification told to the mainstream public in every book about space ever, and all else kept equal, that is probably true. However, rarely is all else kept equal in the real world.

[CBase]

https://arstechnica.com/space/2023/05/a-new-report-finds-nasa-has-spent-an-obscene-amount-of-money-on-sls-propulsion/

has more disturbing details in the article and comment section. Basically it shows that cost+ has only motivation to generate fruitless jobs as long as your paperwork is good enough to explain the problem.

[magnemoe]

11 hours ago, StrandedonEarth said:

The difference between actual cost and amount billed goes into the “black budget” for top secret alien military research projects…

Much easier to hide in the much larger military budget there it also belong. It also has huge boring expenses like base maintenance and exercises. 

[Barzon]

13 hours ago, tater said:

So the SRB contract included Ares I, and the test article they fired before Artemis I, and the SRBs for the next 2 flights—and is $4.4B.

For 8 SRBs.

$550M each. So the boosters alone are $1.1B.

The RS-25s are harder to sort out. The $2.1B contract for the first 16 seems to give a value of $131M per engine, but then there is a continuing contract to 2029 that includes 24 new engines, and additional cost for the 11 of the first 16. Ignoring the initial engines, the contract is $150M/engine, not the $99M I have seen before. It might well be lower than that, in which case the first 16 are more than $131... In short, RS-25s are absurdly expensive.

So an SLS core has between $524M and $600M worth of engines on the bottom, and over a billion in boosters.

The SRB contract also includes BOLE development, & 6 additional flight sets of SRBs.

that $2.1B value for the Adaptation contract includes 1.5b for the J-2X for some inane reason.  The actual money spent on RS-25s in that $2.1B was .6B. 

[tater]

2 hours ago, Barzon said:

The SRB contract also includes BOLE development, & 6 additional flight sets of SRBs.

that $2.1B value for the Adaptation contract includes 1.5b for the J-2X for some inane reason.  The actual money spent on RS-25s in that $2.1B was .6B. 

So AJR got $1.5B for nothing in that? Actually from the OIG footnote:

"c This figure is rounded up from $2.06 billion. The total contract value includes work conducted under the Constellation Program. The CLINs
specific to the RS-25 engines for the SLS total $580.9 million. However, J-2X engine development efforts under the contract have been used to
inform new Engine Controller Unit development and integration onto the RS-25 engines"

So if we want to yank $1.5B, we should also yank the engine controller unit from the RS-25s. At the very least some part of that money is indeed at the bottom of each SLS.

The production contract is $3.6B (I'll subtract the $10.9M passed on) for 24 engines. That's $149.6M per engine.

 

Edited May 26, 2023 by tater

[Meecrob]

On 5/25/2023 at 9:53 PM, Ultimate Steve said:

In aerospace, cost does not have very much to do with raw material cost and technological maturity. It depends some, but other factors dominate.

Much of the cost is in certification. You can get material from the same factory, but the aerospace material can be, for example, 10x the cost of the non-aerospace grade material because the aerospace grade stuff has been tested to finer tolerances. In many cases, the material can be identical, the only difference is one was exposed to expensive tests to determine the exact characteristics of the material.

There is a joke in aviation that a plane is certified when the weight of the paperwork equals the weight of the aircraft.

 

Having said that, the details of this report are way beyond regular aerospace certification costs.