NASA confirms EUS for SLS Block IB design and EM-2 flight

[Chris Bergin]

A lot of meat on those big Upper Stage bones for you here, thanks to Chris Gebhardt doing some fine work with L2 content:

http://www.nasaspaceflight.com/2014/06/nasa-confirms-eus-sls-block-ib-design-em-2-flight/

[RocketmanUS]

So there is a big possibility there will be no crew BLEO flight before 2023. That is almost 20 years since VSE !


Were is the EUS ( Exploration Upper Stage ) to be manufactured and what tooling will be used to make the tanks?



Thanks Chris Gebhardt for the article. Good reporting job  .

[arachnitect]

Looks like a picture of Solar Probe Plus... should we read anything into that?

[savuporo]

Can anyone explain in plain and simple terms, what is the purpose of ICPS ? Do i understand it correct that according to current planning, it will be discarded after EM-1 ?

[ncb1397]

So there is a big possibility there will be no crew BLEO flight before 2023. That is almost 20 years since !

You aren't using the correct metric.

BA - up 180% since 2004
LMT - up 215% since 2004

[Coastal Ron]

Can anyone explain in plain and simple terms, what is the purpose of ICPS ? Do i understand it correct that according to current planning, it will be discarded after EM-1 ?

The ICPS (Interim Cryogenic Propulsion Stage) is actually just an existing Delta IV 2nd stage, so it's not being discarded, just not needed as much now as a temporary stand-in for the real SLS upper stage (now called the EUS).

[Silversheep2011]

Sigh.... is it just me?
 I look at the engineering design and see the x3  panels flying of the lower section of the SLS block and think what a waste.

why not?
1, shorten the design
2, combine the panels with the tank function in a simple Monocoque style
3, combine the bulk heads together

take on war out on waste... waste... waste... then simplify... simplify... simplify...
I know it is not easy

 but surly the benefits are there: low parts count. lower weight, less cost, speeder manufacturing, less 'Gravity 2" parts floating in orbit and so on.

Does anybody know the design process used here And /Or Reasoning?

[robertross]

Just had to do a quick log in and give a 2 thumbs up to Chris G's article.

Very thought provoking.

[Coastal Ron]

Sigh.... is it just me?
 I look at the engineering design and see the x3  panels flying of the lower section of the SLS block and think what a waste.

why not?
1, shorten the design
2, combine the panels with the tank function in a simple Monocoque style
3, combine the bulk heads together

take on war out on waste... waste... waste... then simplify... simplify... simplify...
I know it is not easy

 but surly the benefits are there: low parts count. lower weight, less cost, speeder manufacturing, less 'Gravity 2" parts floating in orbit and so on.

Does anybody know the design process used here And /Or Reasoning?

I wondered about that too.  In looking at the conversations on the L2 side where they have been discussing this, it seems like it's related to the umbilical interface and access heights for the Orion, so they don't have a lot of options for lengthening or shortening the stack in that section.

[edkyle99]

Sigh.... is it just me?
 I look at the engineering design and see the x3  panels flying of the lower section of the SLS block and think what a waste.

why not?
1, shorten the design
2, combine the panels with the tank function in a simple Monocoque style
3, combine the bulk heads together

take on war out on waste... waste... waste... then simplify... simplify... simplify...
I know it is not easy

 but surly the benefits are there: low parts count. lower weight, less cost, speeder manufacturing, less 'Gravity 2" parts floating in orbit and so on.

Does anybody know the design process used here And /Or Reasoning?

Common bulkhead for LOX and LH2 is a tough engineering challenge that increases costs.  Look at Saturn S-II history for that lesson.  Using a carbon composite truss intertank and two separate tanks doesn't add that much weight, especially with a smaller diameter LOX tank.  Since most of the stage mass is in the loaded LOX tank, keeping that tank smaller helps with flight control.  Burying the LOX tank in the interstage reduces vehicle height.  It is a proven design method dating from Delta 3 during the 1990s, with some elements similar to the Straight Eight Delta of the early 1970s.

 - Ed Kyle

[Silversheep2011]

thanks Ed Kyle

It is a proven design method dating from Delta 3 during the 1990s,

So I looked it up on http://en.wikipedia.org/wiki/Delta_III
Interesting I can see the heredity aspect.

But can this design still be improved?
Is this still  the best way to deal with Interstage spacers? { you know its not just limited to SLS design to}
it still looks like waste to me???

Perhaps a further dual function other than dynamic load transference could be derived...
And yes, Saturn S-2 did use a common bulkhead I love that part in the Science discovery  documentary series "Moon Machines' telling about how they used the local Surfies and there surfboard techniques to glass out the tanks!

[clongton]

Can anyone explain in plain and simple terms, what is the purpose of ICPS ? Do i understand it correct that according to current planning, it will be discarded after EM-1 ?

The NASA Authorization Act required the SLS to be operational by December 2016 and NASA felt it could not have a new upper stage ready for flight in time to meet that deadline so they adapted the Delta-IV upper stage to fly on the SLS. They named it ICPS, the "I" being for "interim".

Personally I believe that decision was flawed because of all the work we did for the Jupiter LVs. The conclusion of all our conversations with the engineers and managers who would actually design and build the core and US was that the time frame to get to operational status was much shorter than what NASA has selected for the SLS. That tells me that NASA's time frame is politically driven, not technically. I've stated that elsewhere on this forum. NASA should have just reached for the brass ring and developed the EUS from the beginning, and flown it on EM-1. They absolutely could have done it by the deadline. They chose not to.

[BillyH]

Sigh.... is it just me?
 I look at the engineering design and see the x3  panels flying of the lower section of the SLS block and think what a waste.

The three panels are designed to do that.

http://www.nasaspaceflight.com/2013/11/piecing-together-blowing-apart-eft-1-orion/

[TJL]

Great article, Chris.
However, I have a question pertaining to flying a crew for the first time on an unflown stage.
What is the difference between that and STS-1...where a crew flew an entire unflown vehicle?
Thank you.

[notsorandom]

Great article, Chris.
However, I have a question pertaining to flying a crew for the first time on an unflown stage.
What is the difference between that and STS-1...where a crew flew an entire unflown vehicle?
Thank you.

The Shuttle had to have a crew aboard for the first flight. The capability to land without a pilot was only developed later on in the program and never demonstrated. There were several things that happened on STS-1 that put the vehicle at risk. One I am thinking of in particular is the over pressure way on launch forcing the body flap to be over extended. I suspect that some of the thinking in not flying a crew on an flown stage is a result of two things. One that the loss of Challenger and Columbia has made NASA more risk aware. The other being that there isn't the schedule pressure to move the program along like there was in the Apollo days. There is less of a drive to trade schedule and budget for risk.

[M129K]

but surly the benefits are there: low parts count. lower weight, less cost, speeder manufacturing, less 'Gravity 2" parts floating in orbit and so on.

Does anybody know the design process used here And /Or Reasoning?

Those parts are left in an orbit that causes the parts to burn up before completing even a single orbit.

Also, three panels aren't significant in cost, weight, manufacturing speed (which is pretty unimportant for a rocket flying at most twice a year anyway) and were probably chosen for simplicity and easy design.

Great article, Chris.
However, I have a question pertaining to flying a crew for the first time on an unflown stage.
What is the difference between that and STS-1...where a crew flew an entire unflown vehicle?
Thank you.

STS couldn't land without a crew so it had to fly one from the start.

[savuporo]

Can anyone explain in plain and simple terms, what is the purpose of ICPS ? Do i understand it correct that according to current planning, it will be discarded after EM-1 ?

The ICPS (Interim Cryogenic Propulsion Stage) is actually just an existing Delta IV 2nd stage, so it's not being discarded, just not needed as much now as a temporary stand-in for the real SLS upper stage (now called the EUS).

I know all of that, but it does not really explain the purpose of it. Why wouldn't one simply fly a dummy upper stage ?

[kch]

Can anyone explain in plain and simple terms, what is the purpose of ICPS ? Do i understand it correct that according to current planning, it will be discarded after EM-1 ?

The ICPS (Interim Cryogenic Propulsion Stage) is actually just an existing Delta IV 2nd stage, so it's not being discarded, just not needed as much now as a temporary stand-in for the real SLS upper stage (now called the EUS).

I know all of that, but it does not really explain the purpose of it. Why wouldn't one simply fly a dummy upper stage ?

Same reason one wouldn't fly a dummy first stage -- not enough delta-V to get the job done ... 

[savuporo]

Same reason one wouldn't fly a dummy first stage -- not enough delta-V to get the job done ... 

What job exactly ? I thought EM-1 is primarily about testing the first stage basically.

[kch]

Same reason one wouldn't fly a dummy first stage -- not enough delta-V to get the job done ... 

What job exactly ? I thought EM-1 is primarily about testing the first stage basically.

You're going to do TLI with the first stage?  Good luck -- you won't even get to LEO that way:

http://www.nasaspaceflight.com/2014/04/evolving-plans-human-rating-icps-sls-em-1-mission/