Author Topic: Europa Clipper’s launch date dependent on SLS Mobile Launcher readiness  (Read 27889 times)

Offline zubenelgenubi

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Wow. I didn't realize the schedule had such a dour outlook. One option that wasn't discussed in the article was using the same configuration for EM-1 to launch Europa Clipper. Is this possible or is the Exploration Upper Stage needed for its performance?

SLS Block 1B w/ EUS is the only thing that can inject Europa Clipper into the desired direct trajectory to Jupiter with no gravity assists.
Is there something fundamentally wrong with using gravity assists? I know it takes longer, but I believe all missions to the outer planets so far have used them.
They want to launch direct to increase SC Life Expectancy during transit and in the Jupiter System at Europa. Also Congress said so.

Also, to reduce the human costs of maintaining a highly-trained, highly-PAID staff of hundreds?/a few thousands, and their support mechanisms in working order while the Flagship-class spacecraft is in transit to its destination.

The New Horizons team created some creative solutions around these issues (launch in 2006, flyby Pluto/Charon 9 years later), but there's no substitute for launching a mission, and then getting on with the exploration ASAP, via direct trajectory!  ;D

Also, use of EUS and the matching-size PLF would allow a more massive (larger propellant tanks = more propellant = longer mission/greater mission flexibility at mission target), taller, and wider spacecraft, to accommodate the radiation shielding and multiple-instrument payload, would it not?

(One of our resident experts would be able to express this better than me, I think.)
« Last Edit: 11/05/2017 09:13 PM by zubenelgenubi »
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Offline Marsman

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They are really going to redesign the entire mobile launchers because it will end up with a safety factor of 3.75 instead of 4.0 for the block 1B configuration? Seriously? And that's going to take 3 years?

4.0 is just a made up round number in some spec somewhere, there's nothing magical about it. Plus, it's not like this structure is going to see a high number of duty cycles where additional structural margin is required to actually build a safe structure with launches taking place off of it once every two years at best.

The Saturn V second stage was supposed to be designed to a safety factor of 1.5. North American did a really good job of designing it to 1.5, and it broke pretty much right at 1.5 in integrated loading testing. So, rather than go redesign the entire stage, NASA changed the requirement for manned spaceflight factor of safety to 1.4 and called it good. Since then, every launch vehicle built in the US has been designed to 1.4.

We would never have reached the moon by 1970 if NASA of the 60's was ruled by the bureaucrats who have their noses stuck in specification manuals like they do today. If they would have followed the letter of the specification and made North American go redesign the stage to 1.5, we'd never have made it to the moon in '69.

Good engineering management requires understanding what is vitally important and what doesn't matter. You have to build additional margin into the areas of critical with high uncertainty, and you can accept significantly less in areas where the loads are extremely well understood (i.e. ground support equipment like the mobile launcher).

You could take the hundreds of millions that are going to be spent on this useless ML redesign and use it to do something useful, like figure out how to produce SLS cheaper so you can actually launch it at a reasonable cadence.

Offline Zed_Noir

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....
You could take the hundreds of millions that are going to be spent on this useless ML redesign and use it to do something useful, like figure out how to produce SLS cheaper so you can actually launch it at a reasonable cadence.

NASA already spend hundred of millions converting the current ML from the Ares 1 to SLS Block 1.

As to how to have the SLS be cheaper and launched more often. Get rid of the solid boosters and the mobile launcher IMO.

Offline spacetraveler

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Also, to reduce the human costs of maintaining a highly-trained, highly-PAID staff of hundreds?/a few thousands, and their support mechanisms in working order while the Flagship-class spacecraft is in transit to its destination.

The New Horizons team created some creative solutions around these issues (launch in 2006, flyby Pluto/Charon 9 years later), but there's no substitute for launching a mission, and then getting on with the exploration ASAP, via direct trajectory!  ;D

I don't think so. Cost reduction is definitely not an advantage of this approach. It will cost MUCH more to launch via SLS with direct trajectory than it would with a smaller launcher using gravity assists and paying the ground support team for a few additional years during transit.

Offline Khadgars

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Also, to reduce the human costs of maintaining a highly-trained, highly-PAID staff of hundreds?/a few thousands, and their support mechanisms in working order while the Flagship-class spacecraft is in transit to its destination.

The New Horizons team created some creative solutions around these issues (launch in 2006, flyby Pluto/Charon 9 years later), but there's no substitute for launching a mission, and then getting on with the exploration ASAP, via direct trajectory!  ;D

I don't think so. Cost reduction is definitely not an advantage of this approach. It will cost MUCH more to launch via SLS with direct trajectory than it would with a smaller launcher using gravity assists and paying the ground support team for a few additional years during transit.

If NASA were procuring SLS from someone else, totally agree.  However, that SLS launch will be part of the 1b validation (meaning it would have to be flown regardless).  This makes the Europa Clipper mission cheaper while not affecting SLS budget at all since it has to be flown before EM-2.

Offline eywflyer

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Probable realistic launch plan schedule for SLS:

EM-1   May 2020
SM-1   July 2023
EM-2   June 2024
EM-3   June 2025
SM-2   2026 (whenever the launch window in this year occurs) (plus this is the first flight of the RS-25Es, ASAP will want a unmanned flight of these engines first before a manned one) (this engine set will not be available to support a flight until this time anyway so it could not be done any earlier)
EM-4   2028 (it takes 2 years to deliver 4 RS-25Es on the current contract) (It will require a bigger budget and a new contract to  increase the build rate to deliver 4 engines per year instead of the current contract delivery rate of 2 engines per year)
Unless the engine build rate is increased there is no more launches in the 2020's.

Assumptions:
a) That ML-1 is modified to be a cargo only SLS-1B support.
b) That an ML-2 is constructed with lessons learned to make a crew version of the ML with a budget funded at a level allowing it to be constructed in 5 years starting Oct 2018. This gets a ML available to support the June 2024 EM-2 date at better than 6 months prior to launch date plus a few months of margin.
c) That EC is ready for launch by 6 months prior to its launch date in July 2023.
d) That Europa Lander is ready for launch 6 months prior to its window in 2026.

This schedule seems to be realistic (and depressing). There appears to be no way to get Europa Clipper launched in the 2022 window, regardless of how the ML's are wrangled, which pushes EM-2 to 2024 and results in a 13-year gap between STS-135 and EM-2. One wonders how much longer political support for SLS will endure in this current budgetary and political environment. Any further slips to the schedule would push EM-1 beyond the current presidential term, and EM-2 beyond the next term.

Offline su27k

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that SLS launch will be part of the 1b validation (meaning it would have to be flown regardless).

Sending your most expensive probe on a test flight, what could possibly go wrong...

Offline woods170

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that SLS launch will be part of the 1b validation (meaning it would have to be flown regardless).

Sending your most expensive probe on a test flight, what could possibly go wrong...
[sarcasm]
Nothing. Thanks to NASA insight.
[/sarcasm]


Which btw is exactly how ESA lost Cluster on Ariane 501...

But no worries. Governments self-insure their payloads. Should anything bad happen to Europa Clipper they'll just build another one.
« Last Edit: 11/07/2017 06:22 AM by woods170 »

Offline the_other_Doug

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There seems to be an assumption peeking out behind most of the negative posts here -- that the SLS will almost inevitably fail on its first flight.

What, exactly, is the track record on first flights of new large boosters?  I don't want to count smallsat launch vehicles that are built out of old, degrading solid rocket motors handed down from ICBM programs, or things like that.  Just new large booster systems.

I'm aware of Ariane 5's first flight -- which, IIRC, was an issue with the flight software not being modified from Ariane 4.  Not a hardware issue at all.  More an issue of the programming staff not being willing to give up one of their 12 weeks of paid vacation for that year... ;)

Now, *second* flights, I'm aware of issues, most recently with the CZ-5, and going back at least to to the Saturn V.  But, again, out of large, multi-billion-dollar development programs, how many first flights have failed?

You gotta fly it first at some point, guys -- and ASAP is gonna push hard against flying the first iteration of a given configuration with crew on board.  If it's gonna cost 4 or 5 billion USD to fly the first one, doesn't it make sense to put *something* on it?

And, thinking about it, SLS isn't a Saturn V.  It's not featuring several previously-unflown engine designs (or, in the case of the J-2, previously unflown in a clustered configuration) -- heck, the first several flights of SLS will use previously flown engines.  Has OrbitalATK been pushing to revert the SRB segment joints to the original faulty Shuttle design, or something?

In other words why would people assume that Musk and Bezos can create new engines and boosters that will be perfectly wonderful from the get-go, but SLS, featuring extremely mature engine technology, is a horrendous risk that should never be attempted?

I am not speaking of cost, or suitability of the booster for specific missions -- just an increasingly-less-unspoken assumption that SLS is inherently likely to fail, especially on its first flight.  I'm just not seeing any basis for that prejudice against this launch system.
-Doug  (With my shield, not yet upon it)

Offline envy887

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There seems to be an assumption peeking out behind most of the negative posts here -- that the SLS will almost inevitably fail on its first flight.

What, exactly, is the track record on first flights of new large boosters?  I don't want to count smallsat launch vehicles that are built out of old, degrading solid rocket motors handed down from ICBM programs, or things like that.  Just new large booster systems.

I'm aware of Ariane 5's first flight -- which, IIRC, was an issue with the flight software not being modified from Ariane 4.  Not a hardware issue at all.  More an issue of the programming staff not being willing to give up one of their 12 weeks of paid vacation for that year... ;)

Now, *second* flights, I'm aware of issues, most recently with the CZ-5, and going back at least to to the Saturn V.  But, again, out of large, multi-billion-dollar development programs, how many first flights have failed?

You gotta fly it first at some point, guys -- and ASAP is gonna push hard against flying the first iteration of a given configuration with crew on board.  If it's gonna cost 4 or 5 billion USD to fly the first one, doesn't it make sense to put *something* on it?

And, thinking about it, SLS isn't a Saturn V.  It's not featuring several previously-unflown engine designs (or, in the case of the J-2, previously unflown in a clustered configuration) -- heck, the first several flights of SLS will use previously flown engines.  Has OrbitalATK been pushing to revert the SRB segment joints to the original faulty Shuttle design, or something?

In other words why would people assume that Musk and Bezos can create new engines and boosters that will be perfectly wonderful from the get-go, but SLS, featuring extremely mature engine technology, is a horrendous risk that should never be attempted?

I am not speaking of cost, or suitability of the booster for specific missions -- just an increasingly-less-unspoken assumption that SLS is inherently likely to fail, especially on its first flight.  I'm just not seeing any basis for that prejudice against this launch system.

If you're talking about EM-1, it does have the largest single stage and the largest solid motors ever. But the highest risk item is probably avionics and software, which are harder than hardware to test realistically and are all new, to my understanding.

Europa Clipper would not be on the first flight of SLS, but the second. It would be the first flight of EUS, which is a new stage, again with new software.

Offline ZachF

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Probable realistic launch plan schedule for SLS:

EM-1   May 2020
SM-1   July 2023
EM-2   June 2024
EM-3   June 2025
SM-2   2026 (whenever the launch window in this year occurs) (plus this is the first flight of the RS-25Es, ASAP will want a unmanned flight of these engines first before a manned one) (this engine set will not be available to support a flight until this time anyway so it could not be done any earlier)
EM-4   2028 (it takes 2 years to deliver 4 RS-25Es on the current contract) (It will require a bigger budget and a new contract to  increase the build rate to deliver 4 engines per year instead of the current contract delivery rate of 2 engines per year)
Unless the engine build rate is increased there is no more launches in the 2020's.

Assumptions:
a) That ML-1 is modified to be a cargo only SLS-1B support.
b) That an ML-2 is constructed with lessons learned to make a crew version of the ML with a budget funded at a level allowing it to be constructed in 5 years starting Oct 2018. This gets a ML available to support the June 2024 EM-2 date at better than 6 months prior to launch date plus a few months of margin.
c) That EC is ready for launch by 6 months prior to its launch date in July 2023.
d) That Europa Lander is ready for launch 6 months prior to its window in 2026.

6 launches by 2028.... By then we would have spent >$40 billion on the SLS program.

good god

$6.7 billion per flight. That's $20 from every man, woman, and child in America to throw one of these up.

Offline ZachF

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They are really going to redesign the entire mobile launchers because it will end up with a safety factor of 3.75 instead of 4.0 for the block 1B configuration? Seriously? And that's going to take 3 years?


Of course they want to do it... They get paid by the hour.

Offline the_other_Doug

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There seems to be an assumption peeking out behind most of the negative posts here -- that the SLS will almost inevitably fail on its first flight.

What, exactly, is the track record on first flights of new large boosters?  I don't want to count smallsat launch vehicles that are built out of old, degrading solid rocket motors handed down from ICBM programs, or things like that.  Just new large booster systems.

I'm aware of Ariane 5's first flight -- which, IIRC, was an issue with the flight software not being modified from Ariane 4.  Not a hardware issue at all.  More an issue of the programming staff not being willing to give up one of their 12 weeks of paid vacation for that year... ;)

Now, *second* flights, I'm aware of issues, most recently with the CZ-5, and going back at least to to the Saturn V.  But, again, out of large, multi-billion-dollar development programs, how many first flights have failed?

You gotta fly it first at some point, guys -- and ASAP is gonna push hard against flying the first iteration of a given configuration with crew on board.  If it's gonna cost 4 or 5 billion USD to fly the first one, doesn't it make sense to put *something* on it?

And, thinking about it, SLS isn't a Saturn V.  It's not featuring several previously-unflown engine designs (or, in the case of the J-2, previously unflown in a clustered configuration) -- heck, the first several flights of SLS will use previously flown engines.  Has OrbitalATK been pushing to revert the SRB segment joints to the original faulty Shuttle design, or something?

In other words why would people assume that Musk and Bezos can create new engines and boosters that will be perfectly wonderful from the get-go, but SLS, featuring extremely mature engine technology, is a horrendous risk that should never be attempted?

I am not speaking of cost, or suitability of the booster for specific missions -- just an increasingly-less-unspoken assumption that SLS is inherently likely to fail, especially on its first flight.  I'm just not seeing any basis for that prejudice against this launch system.

If you're talking about EM-1, it does have the largest single stage and the largest solid motors ever. But the highest risk item is probably avionics and software, which are harder than hardware to test realistically and are all new, to my understanding.

Europa Clipper would not be on the first flight of SLS, but the second. It would be the first flight of EUS, which is a new stage, again with new software.

In re EC, I was talking more about the EUS configuration, whatever block- that's being called this week -- Block-1B, if my aging and failing memory is working correctly.

I guess I was sort of taking for granted (and got what I deserved for assuming) that people understood I was talking about the full configuration, not EM-1 with the single-shot interim upper stage.  But that sort of reinforces my point -- the core stage and SRBs will already have flown once before EC flies.

I do get what you're saying about the avionics and software.  I guess I've been assuming, looking at the various applications of Monte Carlo scenario processing and the more-advanced-than-ever virtual test environments, that there has been ample time for all the software to have been thoroughly designed and debugged during this extended development period.  Again, though, I might just be falling into that old trap of what happens when you assume... :(
-Doug  (With my shield, not yet upon it)

Offline oldAtlas_Eguy

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As far as software reliability.

There are two scenarios types:
a) A single entity writes all software and integrates all modules with itself and tests all modules as a single integrated software design throughout the development.

b) Multiple entities writes models with coordination and interface specifications. Testing of modules is independent of the complete. Only after the models have been developed and tested do they go on to integrated whole system testing. This involves many risks:

1- There is significant schedule risk if an interface spec is in error and models have to be rewritten and tested prior to being able to continue with the whole system level testing.
2- There is an problem in problem resolution of software problems because of the involvement of multiple entities and the division of tasking for software fixes. This can end with a sub optimal solution and a fix that has a new unknown error.
3- Costs growth is relative to all the extra effort and time it takes to do coordination between multiple groups as well as the throwing away and starting over when programming designs do not meet the needed integration capability but is unknown until integrated testing.
4- Reliability suffers when communication of programming teams is not "tight". When communication between the module teams is "tight" (under the same organisation and much smaller team sizes) where problems are resolved at the programmers level quickly and early in the development.

SLS is not an example of the first type of software development of a complex software system.

So the risk from a software failure in the first flight and even for the first flight of 1B is high due to how the software is being developed.
« Last Edit: 11/07/2017 06:18 PM by oldAtlas_Eguy »

Offline Jim

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Also, use of EUS and the matching-size PLF would allow a more massive (larger propellant tanks = more propellant = longer mission/greater mission flexibility at mission target), taller, and wider spacecraft, to accommodate the radiation shielding and multiple-instrument payload, would it not?

(One of our resident experts would be able to express this better than me, I think.)

The spacecraft size is already fixed.  It is dual compatible with SLS and other existing launch vehicles.

Offline Jim

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They are really going to redesign the entire mobile launchers because it will end up with a safety factor of 3.75 instead of 4.0 for the block 1B configuration? Seriously? And that's going to take 3 years?

4.0 is just a made up round number in some spec somewhere, there's nothing magical about it. Plus, it's not like this structure is going to see a high number of duty cycles where additional structural margin is required to actually build a safe structure with launches taking place off of it once every two years at best.

The Saturn V second stage was supposed to be designed to a safety factor of 1.5. North American did a really good job of designing it to 1.5, and it broke pretty much right at 1.5 in integrated loading testing. So, rather than go redesign the entire stage, NASA changed the requirement for manned spaceflight factor of safety to 1.4 and called it good. Since then, every launch vehicle built in the US has been designed to 1.4.

We would never have reached the moon by 1970 if NASA of the 60's was ruled by the bureaucrats who have their noses stuck in specification manuals like they do today. If they would have followed the letter of the specification and made North American go redesign the stage to 1.5, we'd never have made it to the moon in '69.

Good engineering management requires understanding what is vitally important and what doesn't matter. You have to build additional margin into the areas of critical with high uncertainty, and you can accept significantly less in areas where the loads are extremely well understood (i.e. ground support equipment like the mobile launcher).

You could take the hundreds of millions that are going to be spent on this useless ML redesign and use it to do something useful, like figure out how to produce SLS cheaper so you can actually launch it at a reasonable cadence.

4.0 is for untested structures

And every launch vehicle built in the US has been designed to 1.25 and not 1.4
« Last Edit: 11/07/2017 08:00 PM by Jim »

Offline Jim

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  This makes the Europa Clipper mission cheaper while not affecting SLS budget at all since it has to be flown before EM-2.

It makes the Europa Clipper budget higher

Offline Jim

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1.  In other words why would people assume that Musk and Bezos can create new engines and boosters that will be perfectly wonderful from the get-go, but SLS, featuring extremely mature engine technology, is a horrendous risk that should never be attempted?

2.  I am not speaking of cost, or suitability of the booster for specific missions -- just an increasingly-less-unspoken assumption that SLS is inherently likely to fail, especially on its first flight.  I'm just not seeing any basis for that prejudice against this launch system.

1.  There is no such assumption.  They will have plenty of test flights before NASA would use them.

2.  It is because of lack of experience.  NASA is not the launch vehicle expert anymore.

Offline redliox

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I was excited to see an article detailing the relationship between Europa Clipper and its intended launcher, SLS.  Likewise, while less important, we can now think of its mission as SM-1 in regards to the SLS roster.  I was an impressive read.

While I would be thrilled to see 'Clipper fly in June '22 (my birthday and a future milestone year for me too), all factors considered I have to admit seeing it fly in (July of was it?) '23 is the more likely best estimate.  I had a feeling the mobile platforms would be a factor; the half-built one being 'recycled' was meant for the lightweight Ares I as opposed to V, the later obviously being what SLS is based on.  It is vaguely encouraging that the ML had some flexibility, but it also sounds like, had it been built-as-intended, that they may as well have started from scratch.  Repurposed or new, at least it is good there will be 2 MLs in the end to segregate and prioritize crew and cargo flights.

Otherwise I figured the EUS would be the subject of worry.  Different needs and different masses from either Ares I or EM-1.  The 'Clipper team would be able to have some confidence on the core and boosters, but EUS would be the wild card.

The probe is definitely going to be the easy item to build for SM-1.

Although not related to this thread, but I wonder what could be an SM-2 flight?  The Europa Lander is barely a concept right now, but I recall there had been tentative thoughts on Mars sample returns using SLS, or a new space telescope later.  Also, if a large element for DSG is called for would it be flown with an SM label instead of EM?
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Online ncb1397

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Probable realistic launch plan schedule for SLS:

EM-1   May 2020
SM-1   July 2023
EM-2   June 2024
EM-3   June 2025
SM-2   2026 (whenever the launch window in this year occurs) (plus this is the first flight of the RS-25Es, ASAP will want a unmanned flight of these engines first before a manned one) (this engine set will not be available to support a flight until this time anyway so it could not be done any earlier)
EM-4   2028 (it takes 2 years to deliver 4 RS-25Es on the current contract) (It will require a bigger budget and a new contract to  increase the build rate to deliver 4 engines per year instead of the current contract delivery rate of 2 engines per year)
Unless the engine build rate is increased there is no more launches in the 2020's.

Assumptions:
a) That ML-1 is modified to be a cargo only SLS-1B support.
b) That an ML-2 is constructed with lessons learned to make a crew version of the ML with a budget funded at a level allowing it to be constructed in 5 years starting Oct 2018. This gets a ML available to support the June 2024 EM-2 date at better than 6 months prior to launch date plus a few months of margin.
c) That EC is ready for launch by 6 months prior to its launch date in July 2023.
d) That Europa Lander is ready for launch 6 months prior to its window in 2026.

6 launches by 2028.... By then we would have spent >$40 billion on the SLS program.

good god

$6.7 billion per flight. That's $20 from every man, woman, and child in America to throw one of these up.

A LEO flight of ~3 mT of logistics or crew costs every man, woman and child in the U.S. about $1 on average. SLS is almost an order of magnitude bigger(70-130 mT vs 7 mt - 22 mT LEO).
« Last Edit: 11/07/2017 08:37 PM by ncb1397 »