Author Topic: NASA's realigning dual Mobile Launcher plan targets extra SLS Block 1 missions  (Read 8801 times)

Offline envy887

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Three years to human rate ICPS and make Orion suitable for astronauts!?

Where does that information come from?

It's possible to interpret the prolonged delay of EUS as evidence that perhaps the software issues are predominantly related to EUS, and that the software for the rest of SLS is more mature because "heritage hardware."

EUS is still being designed. Any software issues are more likely due to elements that are being built now.

For those interested, Block I payload to Europa is only 2.9 t, compared to 8.1 t for Block IB. I estimate FH expendable payload for Europa (for 6,783 m/s delta-V from LEO) to be 6.5 t!

Block 1 should be able to put the entire iCPS plus a ~5 t payload into a ~3000 km x 185 elliptical orbit (roughly LEO+660 m/s), based on being able to put iCPS+Orion into a -40 nm x 975 nm orbit

The NASA Ames Trajectory browser and Biesbroek's Lunar and Interplanetary Trajectories (PDF) both give direct trans-Jupiter injection values of 80 km^2/s^2 for both the 2022 and 2023 windows with 2.28 to 3.33 year coast times, corresponding to LEO+6420 m/s to LEO+6430 m/s.

iCPS should be able to put over 5 t on that transfer if SLS leaves it in 185 x 3000 km LEO.

I'm not sure why Donahue and Sigmon use a 91 km^2/s^2 transfer for Europa, but that it probably why they only get 2.9 tonnes for SLS Block 1 with a 2.7 year coast time.
« Last Edit: 04/24/2018 03:31 PM by envy887 »

Offline Zed_Noir

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Is ICPS human-rating going to happen or not?

It will probably have to be.

As will the SLS software.
Last report wasn't optimistic that was even possible without starting over.

That's an interesting topic because every time I've seen the SLS software problems story, it was never clear whether the software problems relate to SLS core or EUS or ICPS or the entire system. It's possible to interpret the prolonged delay of EUS as evidence that perhaps the software issues are predominantly related to EUS, and that the software for the rest of SLS is more mature because "heritage hardware." On the other hand, we also know that "heritage" only goes so far when we're talking about SLS. So I guess we'll have to wait for more breadcrumbs before we know how bad the software issues are and whether they impact Block I (or the human-rating thereof).

AIUI the SLS control software is only in the upper stage avionics like most 'Heritage launchers'. With said upper stage avionics controlling the entire launch stack.

The implication of that is that you need to re-write the software for each different variant of the SLS.

Online ncb1397

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Kudos for a nice article that clarifies some of the key decision points, timelines, and options.

What I find incomprehensible, and indefensible, if not surprising, is the fact that "due to Orion readiness, it is unlikely both missions [EM-1 and -2] will close the previous multi-year gap by any notable margin."

Three years to human rate ICPS and make Orion suitable for astronauts!? Oh, how things have changed since the flights of Apollo IV and VIII. Somewhere, Gilruth, Low, Kraft, and von Braun are shaking their heads.  :-\

Just because something appears in a NASASpaceflight article doesn't mean it is a fact. See the contention that an expendable Falcon Heavy will cost essentially the same cost that NASA pays for a Falcon 9 with first stage recovered in this very article. The Orion EM-2 spacecraft is where the Orion EM-1 was 2 years ago. And you can expect schedule compression on the second build. So, it comes down to how you interpret "notable margin". I would consider shaving 9+ months off a 33 month gap pretty substantial.

Online AncientU

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Kudos for a nice article that clarifies some of the key decision points, timelines, and options.

What I find incomprehensible, and indefensible, if not surprising, is the fact that "due to Orion readiness, it is unlikely both missions [EM-1 and -2] will close the previous multi-year gap by any notable margin."

Three years to human rate ICPS and make Orion suitable for astronauts!? Oh, how things have changed since the flights of Apollo IV and VIII. Somewhere, Gilruth, Low, Kraft, and von Braun are shaking their heads.  :-\

Just because something appears in a NASASpaceflight article doesn't mean it is a fact. See the contention that an expendable Falcon Heavy will cost essentially the same cost that NASA pays for a Falcon 9 with first stage recovered in this very article. The Orion EM-2 spacecraft is where the Orion EM-1 was 2 years ago. And you can expect schedule compression on the second build. So, it comes down to how you interpret "notable margin". I would consider shaving 9+ months off a 33 month gap pretty substantial.

If you consider the statement that they'll shave 9 months off 'pretty substantial', then you haven't been watching the show.  All kinds of savings have been projected but never realized.

So, I'd recommend that just because something comes out of the mouth of an Orion spokesperson, it doesn't mean it is a fact.  The Orion EM-1 spacecraft is launching on SLS in late 2019... for example.
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Online oldAtlas_Eguy

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What we are seeing is not a realignment of reality for a new plan but the realignment of plans to meet reality.

Give NASA 6 months to create their new plan details and aspirational launch dates. Reality is waiting on the actual delivery of the core for EM-1 by Dec 2019 needed to meet launch date of June 2020. The other item is delivery of core stages is currently at best every 18 months. This puts the second SLS 1 NET Jan 2022. Then the third at NET July 2023. The forth would be a date of NET Jan 2025.

Added:
Note that if EC is not ready for launch in the first window June 2022 there is a third SLS probably available to meet the second window of July 2023. The other item is that vehicle processing flows is currently projected to be a 6 month duration if EC flies in June 2022 then EM-2 would be no earlier than July 2023 because of cores.  If EM- flies as second mission it would have to launch NLT Dec 2022 to be able to do the flow to meet the July 2023 EC window.
« Last Edit: 04/29/2018 05:03 PM by oldAtlas_Eguy »

Offline mike robel

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Like many of us, I shudder and almost fall into despair at the manufacturing schedule for the SLS booster stage.   So, I decided to try to find out how long it took to produce the Saturn V S1C.  According to wikipedia (not my favored source, but it was quick), it seems to be 21 - 23 months for a stage.  7 - 9 months for the tankage and 14 months to complete the stage.  So, about one every two years.

Given that though, of course we launched 4 Saturn Vs from DEC 1968 to July 1969.

Money and size of the contractor force were different of course, but I also think attitude was different. 

In another comparison, a Nimitz or Ford Class Aircraft Carrier has ranges from 10 - 12 years (for lead ships) and 5 - 6 years afterwards.  Of course, we don't throw them away at the end of the first cruise.

Online Lars-J

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Like many of us, I shudder and almost fall into despair at the manufacturing schedule for the SLS booster stage.   So, I decided to try to find out how long it took to produce the Saturn V S1C.  According to wikipedia (not my favored source, but it was quick), it seems to be 21 - 23 months for a stage.  7 - 9 months for the tankage and 14 months to complete the stage.  So, about one every two years.

Thatís not how production works. (At least not sensible production) They has several builds going in different stages of completion on the assembly line.
« Last Edit: 04/29/2018 06:36 PM by Lars-J »

Offline JAFO

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In another comparison, a Nimitz or Ford Class Aircraft Carrier has ranges from 10 - 12 years (for lead ships) and 5 - 6 years afterwards.  Of course, we don't throw them away at the end of the first cruise.

Your comparison is more apt than you thought. Nimitz class was a great carrier, whereas it's looking more and more like the Ford is a kludge of epic proportions.
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Offline mike robel

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@ LARS.

I understand how production works.  I could see how it might take that long to move the stage from the beginning to the end of the process.  They might start at 3 months intervals, but each one takes a relatively long time and they might not enter the production line you pictured at the same time.  Later items might come out faster than the ones at the start of the batch.

I remember watching movies of B-29s, B-36s, etc.  in production (final assembly) and I saw, as a child, Titan I and Titan II missiles in the Martin Marietta - Waterton plant in various stages of production.

Online Chris Bergin

Meeting this week, memo in L2.

SLS Decision Point:

SLS Block 1B's debut is now *officially* NET 2024, assuming the completion of the second Mobile Launcher (ML-2).

Two/three Block 1's from ML-1. ML-1 conversion to 1B "only if funds become available".


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