Author Topic: Europa Clipper’s launch date dependent on SLS Mobile Launcher readiness  (Read 19066 times)


Online rockets4life97

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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?

Offline DreamyPickle

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Any estimates for when the probe itself can be ready?

I remember reading that it's being designed so that it fits on smaller launches and what the SLS provides is a faster trajectory. This might be nullified if it has to wait several years for SLS to be ready.

There is also a lot of risk in launching a 2B flagship mission on a new launcher config.

Online ChrisGebhardt

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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.

Online ChrisGebhardt

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Any estimates for when the probe itself can be ready?

I remember reading that it's being designed so that it fits on smaller launches and what the SLS provides is a faster trajectory. This might be nullified if it has to wait several years for SLS to be ready.

There is also a lot of risk in launching a 2B flagship mission on a new launcher config.

Well, right now Europa Clipper can ready for launch on 4 June 2022 or the TIM wouldn't have set that as the target launch date. ;)  History tells us that the probe's readiness will slip, but right now it's on track to be ready for launch in the June 2022 window.

Due to U.S. Federal laws written by Congress, SLS is the only vehicle that can launch Europa Clipper unless the law is changed.

As for the added risk, that's the "need to add additional testing to the payload and the SLS Block 1B design if Europa Clipper is indeed the first mission to fly on the SLS Block 1B" referenced in the article.
« Last Edit: 11/03/2017 06:03 PM by ChrisGebhardt »

Offline Coastal Ron

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Great article!

It would be interesting to understand what the factors are driving the 33 months to do the conversion, because that is a long time. As a comparison it took 6 years from starting to dig the foundation of the world's tallest building, the Burj Khalifa, until it opened - so is the SLS ML only half as complicated as the Burj Khalifa? It would seem to be far less complicated, but they have different functions so maybe that is a factor.

Is it money?

Is it that the ML has to be disassembled and then reassembled?
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Online AncientU

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Great article!

It would be interesting to understand what the factors are driving the 33 months to do the conversion, because that is a long time. As a comparison it took 6 years from starting to dig the foundation of the world's tallest building, the Burj Khalifa, until it opened - so is the SLS ML only half as complicated as the Burj Khalifa? It would seem to be far less complicated, but they have different functions so maybe that is a factor.

Is it money?

Is it that the ML has to be disassembled and then reassembled?


It is processes.
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Offline AegeanBlue

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So, if I understand correctly a study will follow to see if the current launcher arm can be modified to a cargo only version for Block 1B that will allow it to be within the weight limits, while a new crew only version of the mobile launcher would need to be built so as to fit the weight limit. Were it not for Senator Shelby I would say 2022 is out of the picture just from the launcher side. Then again people in the know in the robotic part of this forum say that it is possible that the payload may slip 2022 anyway. If 2022 is to be pursued is the kind of decision that the NASA administrator needs to consult with the national space council and the Vice President. If Brindestine is approved, which looks likely right now, this may be his very first big decision.

Offline UltraViolet9

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Due to U.S. Federal laws written by Congress, SLS is the only vehicle that can launch Europa Clipper unless the law is changed.

The FY 2016 approps language is contingent on both the orbiter and lander launching in 2022 and on the Administration providing a five-year budget for the same.  The former was highly unlikely before MLS schedule issues, and the latter was almost certainly never going to happen.

The Administration will have to decide how it wants to unpack and deal with this in its FY 2019 budget deliberations (currently ongoing).  Then Congress/Culberson will have to decide if they're still interested in funding Clipper (or not) after the Administration performs its surgery.


Offline TaurusLittrow

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So NASA needs "33 months of work for ML conversion from Block 1 to Block 1B once the EM-1 mission has launched."

Well, by comparison, ML-3, used in 5 manned Apollo launches and 51 Shuttle launches, began construction in 1964 and was completed on March 1, 1965, a maximum of 14 months (though the swing arms were added at a later date).

Granted, different times, different budgets, different priorities, but it does make one wonder.

Offline oldAtlas_Eguy

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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.
« Last Edit: 11/04/2017 04:51 PM by oldAtlas_Eguy »

Offline TaurusLittrow

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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.

It's hard to argue with this timeline (regardless of how depressing it is). I wonder, however, if the SM-2 flight of SLS with Europa Lander (I presume) will really materialize given other heavy lift options (NG/BFR, etc.) that should be available at that time even if gravity assists are necessary.

Regardless of ASAP's opinion, the political pressure will surely favor human missions and finishing construction of the DSG with EM-4 (in place of SM-2) adding the Logistics Module in 2026 and EM-5 bringing the airlock in 2028.

Offline oldAtlas_Eguy

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Unfortunately the SLS schedule we have now is a direct result of the budget cutting decisions made in 2012 to make the SLS fit into a fixed yearly budget cap. This involved shortcuts that now are not that much of a shortcut nor will actually save money. A entirely new ML from ground up could have been built to meet the current actual launch schedule due to other problems in the program. This ML could have been built to meet both SSL-1A and 1B requirements only requiring arm movements. If the decision to skip the 1A and go directly to 1B had been made early enough and with enough budget the first flight would have been a 1B in 2020 with EM-2 in 2022 followed by SM-1 in June 2022. Then EM-3 in 2024. Pushing the engine build up by additional funding would get engines for EM-4 in 2025 with SM-2 in 2026 and the additional EM flights at 1 per year starting 2027 with EM-5,6,and 7.

Offline ncb1397

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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)

Unmanned test flights were never required for all the tinkering that was done during the Shuttle program.

Quote
Over the course of the Space Shuttle program, the RS-25 went through a series of upgrades, including combustion chamber changes, improved welds and turbopump changes in an effort to improve the engine's performance and reliability and so reduce the amount of maintenance required after use. As a result, several versions of the RS-25 were used during the program:[9][22][24][25][30][31][32][33][34]
FMOF (first manned orbital flight) – Certified for 100% rated power level (RPL). Used for the orbital flight test missions STS-1—STS-5 (engines 2005, 2006 and 2007).
Phase I – Used for missions STS-6—STS-51-L, the Phase I engine offered increased service life and was certified for 104% RPL.
Phase II (RS-25A) – First flown on STS-26, the Phase II engine offered a number of safety upgrades and was certified for 104% RPL & 109% full power level (FPL) in the event of a contingency.
Block I (RS-25B) – First flown on STS-70, the Block I engines offered improved turbopumps featuring ceramic bearings, half as many rotating parts and a new casting process reducing the number of welds. Block I improvements also included a new, two-duct powerhead (rather than the original design, which featured three ducts connected to the HPFTP and two to the HPOTP), which helped improve hot gas flow, and an improved engine heat exchanger.
Block IA (RS-25B) – First flown on STS-73, the Block IA engine offered main injector improvements.
Block IIA (RS-25C) – First flown on STS-89, the Block IIA engine was an interim model used whilst certain components of the Block II engine completed development. Changes included a new large throat main combustion chamber (which had originally been recommended by Rocketdyne in 1980), improved low pressure turbopumps and certification for 104.5% RPL to compensate for a 2 seconds (0.020 km/s) reduction in specific impulse (original plans called for the engine to be certified to 106% for heavy International Space Station payloads, but this was not required and would have reduced engine service life). A slightly modified version first flew on STS-96.
Block II (RS-25D) – First flown on STS-104, the Block II upgrade included all of the Block IIA improvements plus a new high pressure fuel turbopump. This model was ground-tested to 111% FPL in the event of a contingency abort, and certified for 109% FPL for use during an intact abort.
https://en.wikipedia.org/wiki/Space_Shuttle_main_engine

Offline oldAtlas_Eguy

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The problem is there was no alternative in the Shuttle program. You flew manned or not at all.

It could have flown unmanned but the state of the art was yet to be trustworthy for accomplishing this, hence the requirement to always be manned flights.

Since then the safety community has become more risk averse when it comes to a manned program. This not to say it could not be done just less likely in the current safety environment for manned flight.

Offline ncb1397

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The problem is there was no alternative in the Shuttle program. You flew manned or not at all.

It could have flown unmanned but the state of the art was yet to be trustworthy for accomplishing this, hence the requirement to always be manned flights.

Since then the safety community has become more risk averse when it comes to a manned program. This not to say it could not be done just less likely in the current safety environment for manned flight.

You could have done the 2 man crew layout that STS-1 used at the very least. All the flight tests with different versions of the SSME were done with a more normal complement of 5-7 crew. Even STS-26 directly after Challenger that was also the first flight of an RS-25A
« Last Edit: 11/04/2017 08:49 PM by ncb1397 »

Offline spacetraveler

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Amazing article.

Unfortunately it really underscored for me just how poorly thought out the whole SLS program is and why it probably will be cancelled.

I have supported it in the past, but I can't really say that cancelling it will be the wrong decision given how horribly expensive and unproductive it has become.

Offline spacetraveler

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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.

Offline russianhalo117

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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.

Offline Oli

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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.

There are aliens on Europa and it's very important to make first contact before the Chinese do.

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.

Online 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.

Online 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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Offline 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 »

Offline pathfinder_01

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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).

If costs scaled that way it would be $10 not $20. The thing has got such a slow flight rate that it is pointless. Multiple flights of other launch vehicles could do much the same purpose. The Clipper could be sent on its way using other vehicles WITH less risk.

Offline Proponent

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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?

Not necessarily, even ignoring Jim's comment to the effect the the spacecraft has already been sized.  The reason is that the SLS-launched version of the mission involves a direct trajectory to Europa, whereas the Atlas V version involves multiple slingshots around the inner solar system and hence a lower delta-V.  In fact, my recollection is that according to previous posts on this topic, an EC specifically designed for Atlas V could be heavier than one specifically designed for SLS (can anybody find old posts on this topic?).

Offline Proponent

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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.

I'm a critic of SLS, but I don't expect it or EUS to fail on first flight.  Surely, though, it's beyond dispute that launching the very expensive EC on SLS is much riskier than launching it on the very well proven Atlas V.

EDIT:  Broke into two sentences to avoid clumsy double-"but."  Added "flight" in first sentence. 
« Last Edit: 11/12/2017 08:50 PM by Proponent »

Offline AegeanBlue

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Since I am more familiar with the Science part of NASA (though still a learned amateur) than the launcher part here are a few answers about the payloads:

1. If you see the various presentations that Papalardo has done on Europa Clipper, Atlas V is both weight and volume limited. It is not just that it will take a series of flybys to get to Jupiter and Europa, Clipper is running into the maximum weight limit of Atlas V and into the volume limit of its shroud. Now the other lesser alternatives beyond Atlas V are Delta IV Heavy and Falcon Heavy. Delta IV Heavy also has a shroud volume issue, though not the weight issue. It does not really get mentioned that much in the presentations, most likely if like with the Parker Solar Probe they run into a weight problem while designing for Atlas V they can switch, and become the third NASA mission on Delta IV Heavy after EFT-1 and Parker Solar Probe. They have asked SpaceX what is the payload shroud and lifting power limits for Falcon Heavy. As per the most recent presentation I saw in the summer (I have not seen yet the November 2nd presentation on LPI) SpaceX had not given a formal answer to the Europa Clipper team.

2. The Space Science missions for SLS outlined so far are Europa Clipper in 2022 (Not Yet Approved for SLS!), Mars Sample Return (Not Approved in general), Europa Lander 2026 (legislated by Congress but no new start approval), Uranus or Neptune orbiter in 2028 or more likely 2030 (somewhere in the pre-decadal mission planning). Getting the Next Mars Orbiter approved, which will carry telecommunications infrastructure for the surface rover, an imager to replace what is on MRO, and ion drive for testing plus whatever instrument contributions foreign partners give and is supposed to launch in 2022, has yet to happen. Mars Sample Return, has seen many studies but little actual work. Now if Europa Lander does take place, it might just eat up both MSR and the Uranus or Neptune orbiters. It will be the heaviest space probe ever, surpassing the record of Soviet Mars probes, and all that for a few battery powered hours on the surface of Europa.

I know that EM is exploration mission, but what does SM mean and where does that term originate?

Offline ncb1397

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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.

I'm a critic of SLS, but I don't expect it or EUS to fail on first, but surely it's beyond dispute that launching the very expensive EC on SLS is much riskier than launching it on the very well proven Atlas V.

Were you this adamant that the billion dollar New Horizons probe not use the first Atlas 551(7th Atlas V overall) and instead use a smaller flight tested vehicle even if it took longer? And that was a nuclear payload.

Edit: Anyways, you probably should watch what you wish for. If NASA gets jittery about putting humans or Europa Clipper on the first SLS Block 1B, they will just find some <$500 million equipment for the first launch and then launch EC after that.
« Last Edit: 11/07/2017 11:17 PM by ncb1397 »

Offline Khadgars

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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.

I really do hate these analogies.  You could literally do this for every single Government agency.

DoD is now $700 Billion or $2,167.18 per person per year to do a bunch of things I mostly disagree with.

You are now complaining about $123 per person spread over 10 years .  I simply don't get the constant, selective outrage.
« Last Edit: 11/08/2017 03:14 PM by Khadgars »

Offline oldAtlas_Eguy

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OIG report on budget shortfalls due to "challenges encountered" impacts to SLS schedule.
http://spacenews.com/nasa-inspector-general-warns-limited-budget-reserves-could-delay-key-programs/


SLS program has only a 1% or less budget reserve thru into 2019.

A perspective the SLS program "consumes" $5M a day in funds. 1% is only $18M. That level of budget margin can only handle minor items and not even that many in order to keep on schedule. If more funds are needed to handle a problem then for every $5M in additional costs encountered above the $18M budget reserve a 1 day slip happens.

What this is such that schedule risk for any mission planning is HIGH. Because even small things like a one day work stoppage for weather can cause slips because there is no funds to pay for some overtime to catch back up. The hurricanes this year caused work stoppages in Michoud and KSC:
1)  for about a week (multiple hurricanes without any damage or return limitations just the hurricanes themselves causing a ~3 day work stoppage during each hurricane)
2) and about 3 weeks at KSC (prior [getting ready for the hurricane] and post [power and water restoration limitations on work crews]).

Additionally work stoppage for review, problem correction, and rework has happened caused by this work being the first of its kind with little experience in performing the specific procedures such that the errors in following or in the procedure themselves causeing significant fabrication delays.

Every time these events happen more funds are needed and any budget margin is steadily consumed. With a new budget year starting 1 Oct 2017, any new scheduled Launch date has a budget margin remaining for this year of $18M. But if this new budget year needs to spend more like happened in 2017 expect more slips.

Added: A small treatise about how schedules are created and managed. They have the best possible end date and then the current reality end date which is the best case end date at a given current point in time. This movement of the best case end date over time is the item called schedule margin. The May date of 2020 contains an average schedule slip of 1 month over 6 months of accomplishment of tasks. In 2017 the slip caused by events both due to errors and weather totaled greater than 6 months added to the best case end date. The other item was that the program was already behind by 6 months. If you use the 2017 worst case as an evaluation of when the launch date schedule with margins should be then add 12 months to the Dec 2019 date for EM-1 giving Dec 2020. I do not think that NASA will encounter several years in a row as bad as this year has been.

EC launch date is dependent on 33 months added to the EM-1 date for ML work. So if things turn out really bad schedule wise then 33 months added to the worst case Dec 2020 date is Aug 2023. This could be a challenge for EC and for NASA to make sure that EM-1 launches earlier than Nov 2020 and does so successfully. But even if EM-1 is not fully successful depending on the nature of the failure it may not have an impact on the EC launch date because it is almost 3 years or more into the future giving time for corrections and testing to the flight hardware.
« Last Edit: 11/08/2017 04:55 PM by oldAtlas_Eguy »

Offline kdhilliard

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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?
This also struck me as strange.  I would have thought that they would have simply done some additional engineering studies on the crawler to verify that the it could handle to load and then run with 3.74.  They say that any idiot can build a bridge that stands, but it takes an engineer to design a bridge that barely stands.

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 crawler-transporter isn't even present during launch, is it?  Doesn't it drop off the ML and then return post-launch to pick it back up?
« Last Edit: 11/10/2017 11:17 AM by kdhilliard »

Offline Steven Pietrobon

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And every launch vehicle built in the US has been designed to 1.25 and not 1.4

My understanding is that Falcon 9 was built to 1.4. I also believe that Saturn IB, Saturn V and Space Shuttle are 1.4.

https://www.nasa.gov/pdf/164283main_2nd_exp_conf_24_Commercial%20Opportunities_SpaceX_MrEMusk.pdf

"NASA man-rating factor of safety (1.4 for Falcon 9 vs. 1.25 for typical expendable launch vehicle)"
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Online Robotbeat

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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.
What's the size and mass and c3?
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Offline Proponent

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I'm a critic of SLS, but I don't expect it or EUS to fail on first, but surely it's beyond dispute that launching the very expensive EC on SLS is much riskier than launching it on the very well proven Atlas V.

Were you this adamant that the billion dollar New Horizons probe not use the first Atlas 551(7th Atlas V overall) and instead use a smaller flight tested vehicle even if it took longer? And that was a nuclear payload.

By the time an Atlas V 551 launched New Horizions, the Atlas V core had already flown 6 times, as you point out, the SRBs had been flown 7 times, and the Centaur had flown many times.  Flying 5 with 5 SRBs when at most 3 had flown before was a risk factor, but a small one compared to flying on the second ever SLS and first ever EUS.

Offline Khadgars

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I'm a critic of SLS, but I don't expect it or EUS to fail on first, but surely it's beyond dispute that launching the very expensive EC on SLS is much riskier than launching it on the very well proven Atlas V.

Were you this adamant that the billion dollar New Horizons probe not use the first Atlas 551(7th Atlas V overall) and instead use a smaller flight tested vehicle even if it took longer? And that was a nuclear payload.

By the time an Atlas V 551 launched New Horizions, the Atlas V core had already flown 6 times, as you point out, the SRBs had been flown 7 times, and the Centaur had flown many times.  Flying 5 with 5 SRBs when at most 3 had flown before was a risk factor, but a small one compared to flying on the second ever SLS and first ever EUS.

By the same logic, the RS-25 & solid boosters will have flown on 136 missions (135 STS, 1 SLS), and the core stage will have been flight proven one (1) SLS mission.  The RL-10 engines on the EUS have been flown since 1963.

Offline mike robel

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I buy the logic for the RS-25s, but they are not the same engines that have flown previously.  Designs and details are different (and I think even from the previously flown engines to be used on the SLS).

The SRBs are a new 5 segment design, different chemical make up (as I recall), and a different nozzle, with only 2 test firings, not under flight conditions plus 2 for the first flight of SLS.

The RL-10s are not the same as flown in 1963, but do have more recent flight heritage.

Offline Proponent

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By the time an Atlas V 551 launched New Horizions, the Atlas V core had already flown 6 times, as you point out, the SRBs had been flown 7 times, and the Centaur had flown many times.  Flying 5 with 5 SRBs when at most 3 had flown before was a risk factor, but a small one compared to flying on the second ever SLS and first ever EUS.

By the same logic, the RS-25 & solid boosters will have flown on 136 missions (135 STS, 1 SLS), and the core stage will have been flight proven one (1) SLS mission.  The RL-10 engines on the EUS have been flown since 1963.

There is more to a stage than its engines.

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I buy the logic for the RS-25s, but they are not the same engines that have flown previously.  Designs and details are different (and I think even from the previously flown engines to be used on the SLS).

The SRBs are a new 5 segment design, different chemical make up (as I recall), and a different nozzle, with only 2 test firings, not under flight conditions plus 2 for the first flight of SLS.

The RL-10s are not the same as flown in 1963, but do have more recent flight heritage.

Just a correction, 5-segment SRBS have been test fired 5 times, 3 development test fires (in 2009, 2010, and 2011) and 2 qualification test fires (in 2015 and 2016).
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Offline mike robel

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I buy the logic for the RS-25s, but they are not the same engines that have flown previously.  Designs and details are different (and I think even from the previously flown engines to be used on the SLS).

The SRBs are a new 5 segment design, different chemical make up (as I recall), and a different nozzle, with only 2 test firings, not under flight conditions plus 2 for the first flight of SLS.

The RL-10s are not the same as flown in 1963, but do have more recent flight heritage.

Just a correction, 5-segment SRBS have been test fired 5 times, 3 development test fires (in 2009, 2010, and 2011) and 2 qualification test fires (in 2015 and 2016).

Thanks for the correction.

Offline Proponent

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1. If you see the various presentations that Papalardo has done on Europa Clipper, Atlas V is both weight and volume limited. It is not just that it will take a series of flybys to get to Jupiter and Europa, Clipper is running into the maximum weight limit of Atlas V and into the volume limit of its shroud.

Thanks -- can you give me a pointer to the relevant presentations?

Offline vjkane

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Thanks -- can you give me a pointer to the relevant presentations?

Check out the link below.  I don't know if all the trajectory options are still valid with the current mass

https://sites.nationalacademies.org/cs/groups/ssbsite/documents/webpage/ssb_172023.pdf

Offline redliox

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Thanks -- can you give me a pointer to the relevant presentations?

Check out the link below.  I don't know if all the trajectory options are still valid with the current mass

https://sites.nationalacademies.org/cs/groups/ssbsite/documents/webpage/ssb_172023.pdf

I find it amusing that the option for the single EGA opens on my birthday that year  ;D
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Offline AegeanBlue

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Thanks -- can you give me a pointer to the relevant presentations?

Check out the link below.  I don't know if all the trajectory options are still valid with the current mass

https://sites.nationalacademies.org/cs/groups/ssbsite/documents/webpage/ssb_172023.pdf

If my memory does not fail me the Europa Clipper presentation where they discuss in detail what the launch options are, including how SpaceX had not responded, is this Von Karman lecture:

https://www.jpl.nasa.gov/events/lectures_archive.php?year=2016&month=2

It turns out a little bit further back than what I thought. The most recent Papalardo lecture at the LPI is available here on youtube:



The lecture is about Europa, with details about Clipper in the end. The most recent news I heard in there is that apparently during flyby Clipper will generate so much data the processing system will not be able to handle it so they will use a more primitive system instead. Alas, I would like that explained: will they record everything a then process it afterwards before transmitting it to Earth, or will they not record it when it goes above the system's capability. Granted, this is the wrong thread for this question.

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Cassini flew on the first Titan IVB/Centaur in 1997.  (Some of the "1st flight" risk of Titan IVB, which derived from the new the new Hercules SMRU solid rocket boosters, apparently had been retired by its/their first flight earlier in 1997. Cassini was the second Titan IVB flight.)

I assume NASA, USAF, and the contractors had procedures and tests to draw down the risks of launching Cassini on a new launch vehicle model.  Is my assumption correct?
***

Another lecture on Europa and Europa Clipper by Dr. Robert Pappalardo, dating May 12, 2016, as part of that year's Exploring Space Lecture series, National Air and Space Museum.



***

Chris Gebhardt's article spurred a vigorous discussion at our Tuesday astronomy lunch today!
« Last Edit: 11/14/2017 08:25 PM by zubenelgenubi »
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Offline Proponent

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The lecture is about Europa, with details about Clipper in the end. The most recent news I heard in there is that apparently during flyby Clipper will generate so much data the processing system will not be able to handle it so they will use a more primitive system instead. Alas, I would like that explained: will they record everything a then process it afterwards before transmitting it to Earth, or will they not record it when it goes above the system's capability.

The spacecraft, being in orbit around not Europa but Jupiter, will have brief close fly-bys every couple of weeks.  Lots of data will be recorded during each fly-by and then transmitted at a leisurely rate during the long lull before the next fly-by.

Offline deruch

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I'm a critic of SLS, but I don't expect it or EUS to fail on first, but surely it's beyond dispute that launching the very expensive EC on SLS is much riskier than launching it on the very well proven Atlas V.

Were you this adamant that the billion dollar New Horizons probe not use the first Atlas 551(7th Atlas V overall) and instead use a smaller flight tested vehicle even if it took longer? And that was a nuclear payload.

By the time an Atlas V 551 launched New Horizions, the Atlas V core had already flown 6 times, as you point out, the SRBs had been flown 7 times, and the Centaur had flown many times.  Flying 5 with 5 SRBs when at most 3 had flown before was a risk factor, but a small one compared to flying on the second ever SLS and first ever EUS.

By the same logic, the RS-25 & solid boosters will have flown on 136 missions (135 STS, 1 SLS), and the core stage will have been flight proven one (1) SLS mission.  The RL-10 engines on the EUS have been flown since 1963.

NASA LSP's ELV Certification rules (LSP-PLN-324.01) lay out what constitutes a common vehicle configuration, what upgrades/modifications require delta-qualification, and what changes constitute a new vehicle configuration and therefore full recertification.  Addition/deletion of strap-on motors are explicitly listed as modification/upgrade and wouldn't require treating the first Atlas V 551 as a new configuration.  The requirements are: "For upgraded or modified vehicle configurations, NASA requires technical insight into the design, manufacturing, testing, integration, and launch of the affected systems and launch vehicle."

Conversely with SLS, switching to the EUS would very definitely be considered a major change and therefore require new certification:  "Examples of vehicle configuration changes include the replacement of engine types, core propulsive stages, and/or major airframe structures."

Treating them differently is not only totally reasonable but is also fully consonant with the official policy and directives of NASA (at least in the hypothetical that SLS was offered by an external provider; in reality, SLS is explicitly exempted from having to comply with the above).
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Offline Jim

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Since I am more familiar with the Science part of NASA (though still a learned amateur) than the launcher part here are a few answers about the payloads:

1. If you see the various presentations that Papalardo has done on Europa Clipper, Atlas V is both weight and volume limited. It is not just that it will take a series of flybys to get to Jupiter and Europa, Clipper is running into the maximum weight limit of Atlas V and into the volume limit of its shroud. Now the other lesser alternatives beyond Atlas V are Delta IV Heavy and Falcon Heavy. Delta IV Heavy also has a shroud volume issue, though not the weight issue. It does not really get mentioned that much in the presentations, most likely if like with the Parker Solar Probe they run into a weight problem while designing for Atlas V they can switch, and become the third NASA mission on Delta IV Heavy after EFT-1 and Parker Solar Probe. They have asked SpaceX what is the payload shroud and lifting power limits for Falcon Heavy. As per the most recent presentation I saw in the summer (I have not seen yet the November 2nd presentation on LPI) SpaceX had not given a formal answer to the Europa Clipper team.


There are no volume issues with existing fairings.  EC is designed to fly in them.  Even if EC flies on SLS, it still could be in a 5m fairing

Offline oldAtlas_Eguy

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Since I am more familiar with the Science part of NASA (though still a learned amateur) than the launcher part here are a few answers about the payloads:

1. If you see the various presentations that Papalardo has done on Europa Clipper, Atlas V is both weight and volume limited. It is not just that it will take a series of flybys to get to Jupiter and Europa, Clipper is running into the maximum weight limit of Atlas V and into the volume limit of its shroud. Now the other lesser alternatives beyond Atlas V are Delta IV Heavy and Falcon Heavy. Delta IV Heavy also has a shroud volume issue, though not the weight issue. It does not really get mentioned that much in the presentations, most likely if like with the Parker Solar Probe they run into a weight problem while designing for Atlas V they can switch, and become the third NASA mission on Delta IV Heavy after EFT-1 and Parker Solar Probe. They have asked SpaceX what is the payload shroud and lifting power limits for Falcon Heavy. As per the most recent presentation I saw in the summer (I have not seen yet the November 2nd presentation on LPI) SpaceX had not given a formal answer to the Europa Clipper team.


There are no volume issues with existing fairings.  EC is designed to fly in them.  Even if EC flies on SLS, it still could be in a 5m fairing
Yes. This is entirely due to that SLS is not an assured available launcher since it has yet to fly, even deliver complete stages for testing except the SRBs. So it must still fit in a faring on an alternate LV.

Offline Proponent

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Check out the link below.  I don't know if all the trajectory options are still valid with the current mass

https://sites.nationalacademies.org/cs/groups/ssbsite/documents/webpage/ssb_172023.pdf

Very interesting --I had not known about the possibility of trajectory with a major post-departure delta-V.  I wonder if any particularly stage is in mind for that.

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Very interesting --I had not known about the possibility of trajectory with a major post-departure delta-V.  I wonder if any particularly stage is in mind for that.

These would be done with onboard storable propulsion, i.e. the spacecraft's main propulsion system. Cassini for example did a 450 m/s "deep space maneuver" (compare to 626 m/s of Saturn orbit insertion).

Juno also performed two large DSMs, in the 400 m/s range each.
« Last Edit: 11/16/2017 06:29 PM by ugordan »

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Quote
However… this is the desired plan with no money – at present – to execute as Congress must approve the additional funds needed to build a brand new ML, and with such funds becoming available before the start of FY 2019 on 1 October 2018 an extremely unlikely possibility, the ML-2 desire is – at present – just that.  A desire.

Actually, If you look at the House and Senate FY2018 funding amounts, you get the following:

Ground Systems
Request: $460.4
Senate: $600.0 ($139.6 million above request)
House: $545.0  ($84.6 million above request)
http://spacenews.com/senate-restores-funding-for-nasa-earth-science-and-satellite-servicing-programs/

Presumably. any additional funds above the request is not accounted as being spoken for in the plan of record with no new ML.

Bill Hill put another mobile launcher at a cost of $350-$500 million range depending on what exactly the makeup of the ML was. The additional funds for FY2018 represent between 17%(House) and 27%(Senate) of the highest estimated cost for the 2nd ML.
« Last Edit: 11/25/2017 06:25 PM by ncb1397 »

Offline oldAtlas_Eguy

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The article
http://spacenews.com/nasa-weighs-new-mobile-launcher-for-sls/
puts the cost of a new ML at $300M + the cost of what it takes to modify the ML-1 in which a new ML-2 that supports SLS 1B but the ML-1 would only support SLS 1A since it would no longer be modified due to lack of funds.

The start date would be if it is requested in the next budget FY2019 of 1 Oct 2018 at earliest. It is always possible for if there is some funds to start it earlier but you still need Congressional authority to obligate the government to any across FY projects. At the current rate of legislation that authority may be sometime in Jan 2019.

But there is one question that was not answered in the article and that was how long would it take to build a new ML once the work started? How long has it taken/will take for the first ML to be built?

That value could be used as a way to evaluate whether a new ML can meet the schedules needed (available earlier than a ML-1 reworked and a delayed to June 2020 EM-1 launch date. That would be a time to build of < 53 months. Any longer and a new ML does not solve schedule problems but causes more schedule problems.

Offline oldAtlas_Eguy

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But there is one question that was not answered in the article and that was how long would it take to build a new ML once the work started? How long has it taken/will take for the first ML to be built?


The Mobile Launcher contract was awarded to Hensel Phelps in May 2008.
source: https://www.nasa.gov/home/hqnews/2008/may/HQ_C08025_Ares_MLP_contract.html

Ares 1X launched from it in October of 2009. The Ares 1 mobile launcher is simpler than the SLS mobile launcher though.
The basic item was when was the work started to modify the ML for SLS-1A (EM-1). I do know the ML is still under construction (modification). With a target completion date of June 2018. What I do not know is when its actual work started.

Offline ncb1397

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But there is one question that was not answered in the article and that was how long would it take to build a new ML once the work started? How long has it taken/will take for the first ML to be built?


The Mobile Launcher contract was awarded to Hensel Phelps in May 2008.
source: https://www.nasa.gov/home/hqnews/2008/may/HQ_C08025_Ares_MLP_contract.html

Ares 1X launched from it in October of 2009. The Ares 1 mobile launcher is simpler than the SLS mobile launcher though.
The basic item was when was the work started to modify the ML for SLS-1A (EM-1). I do know the ML is still under construction (modification). With a target completion date of June 2018. What I do not know is when its actual work started.

What would that tell you? A new build isn't using that layout. It isn't going to be an Ares 1 platform modified for SLS. I believe that the Ares 1-X used a different launch platform than the one that was contracted in 2008. It was a shuttle platform so what I said before wasn't correct.

Quote
The Mobile Launcher, completed in August 2010 at a cost of
$234 million, consists of a two-story base, a 355-foot-tall launch umbilical tower, and
facility ground support systems that include power, communications, and water.
https://oig.nasa.gov/audits/reports/FY12/IG-12-022.pdf

The original ML configuration for Ares 1 therefore took 2 years and 3 months from contracting to delivery. An SLS platform would be more complex likely putting the build length at 3+ years.
« Last Edit: 12/01/2017 10:44 PM by ncb1397 »

Offline oldAtlas_Eguy

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If it takes more than 3 years to build it would not support the EC launch date window of June 2022. Because a 3 year build time with completion of ML occurring soon enough for the EC SLS stacking to start in Jan 2022 the build has to start on or prior to Dec 2018. Meaning it will either take 3 years or it might as well take 4 years. Since the next window is July 2023. A larger cost ($300M more) than that for the modification 33 month effort usually means a longer time frame as well.

All of the time frames all point to the same goal post of support for an EC launch July 2023. And unlikely will support a EC launch date with the modified or a new ML of June 2022.

Online AncientU

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If it takes more than 3 years to build it would not support the EC launch date window of June 2022. Because a 3 year build time with completion of ML occurring soon enough for the EC SLS stacking to start in Jan 2022 the build has to start on or prior to Dec 2018. Meaning it will either take 3 years or it might as well take 4 years. Since the next window is July 2023. A larger cost ($300M more) than that for the modification 33 month effort usually means a longer time frame as well.

All of the time frames all point to the same goal post of support for an EC launch July 2023. And unlikely will support a EC launch date with the modified or a new ML of June 2022.

One consideration is that both the ML-1 modifications and new ML-2 will need to be built in parallel.  What impact this will have on extending the model schedules (which were each single track builds) that you used is difficult to predict -- but it won't shorten them for sure.

I've managed a dual build schedule, where the team was matrixed between the projects.  Many unforeseen delays occur due to critical resource constraints.  A guaranteed delay occurs when the final push is on for whichever project finishes first -- the second place project languishes for the duration of that final push.
« Last Edit: 12/03/2017 11:22 AM by AncientU »
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Offline Darkseraph

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http://www.planetary.org/blogs/jason-davis/2017/20171128-clipper-slipper.html

Interesting article about this problem, with a few good images of the changes required to the Mobile Launcher to support Europa Clipper/EM-2.
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Here's a new article which sounds like they are considering not modifying ML-1, just building ML-2.
Quote
NASA weighs new mobile launcher for SLS
Quote
Bob Cabana, director of the Kennedy Space Center, also supports building a new mobile launcher rather than modifying the existing one. He said earlier at the NASA Advisory Council committee meeting that he took Bill Gerstenmaier, NASA associate administrator for human exploration and operations, on a tour of the current launcher “so he could appreciate the complexity of this thing and why I believe we need a second mobile launcher rather than modifying this one.”

Cabana offered an analogy for the work needed to modify the mobile launcher for the SLS Block 1B. “I’m going to cut off my head and add six inches to my body,” he said. “That’s essentially what you’re doing. You’re taking a very complex system — all the wire systems and everything else that is on that thing — and raising it up to extend it for the larger vehicle.”
Quote
Hill said a more detailed discussion about the tradeoffs of modifying the existing launcher versus building a new one could take place at the committee’s next meeting, which would be around March 2018 based on the schedules of previous meetings. “By then,” he said, “we should know whether we’re going with modifying this mobile launcher or having the authority to go get a new one.”
So, built a mobile launcher for Ares X-1, built a mobile launcher for EM-1, and now going to build another for EM-2. 
Even the mobile launchers are expendable.
« Last Edit: 12/05/2017 09:28 PM by AncientU »
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Offline rcoppola

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Love this quote from Gen. Hyten, “I’m worried about the future. Somehow this country lost the ability to go fast. I don’t know how that happened,” he said. “We take four years to study a problem before we do anything. We do four years of risk reduction on technologies we built 50 years ago.”

http://spacenews.com/battle-brewing-in-the-pentagon-over-military-space-investments/

Pretty much sums up the entirety of the SLS program. I'd de-manifest EC from SLS at this point. NG, Vulcan, Block5 based FH, BFR(?)....
« Last Edit: 12/05/2017 10:07 PM by rcoppola »
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Love this quote from Gen. Hyten, “I’m worried about the future. Somehow this country lost the ability to go fast. I don’t know how that happened,” he said. “We take four years to study a problem before we do anything. We do four years of risk reduction on technologies we built 50 years ago.”

http://spacenews.com/battle-brewing-in-the-pentagon-over-military-space-investments/

Pretty much sums up the entirety of the SLS program. I'd de-manifest EC from SLS at this point. NG, Vulcan, Block5 based FH, BFR(?)....

Tell him to read "Up the Organisation" by Robert C. Townsend.

Hold standing meetings standing up. It keeps them short, to the point and on important subjects.

Offline mike robel

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Love this quote from Gen. Hyten, “I’m worried about the future. Somehow this country lost the ability to go fast. I don’t know how that happened,” he said. “We take four years to study a problem before we do anything. We do four years of risk reduction on technologies we built 50 years ago.”

http://spacenews.com/battle-brewing-in-the-pentagon-over-military-space-investments/

Pretty much sums up the entirety of the SLS program. I'd de-manifest EC from SLS at this point. NG, Vulcan, Block5 based FH, BFR(?)....

Well, I think he's right.  That's one reason why things like the C-130, CH-47, B-52, RD-107/Soyuz, and (almost) the Delta II are still flying today.  Yeah, they've been refurbished and modified, but the basic design is so good that it can't really be replaced.

All this new-fangled engineering we do now is not any faster or better than what we did in the 40's, 50's, and 60's.

Offline Steven Pietrobon

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So, built a mobile launcher for Ares X-1, built a mobile launcher for EM-1, and now going to build another for EM-2. 
Even the mobile launchers are expendable.

Ares I-X used the Space Shuttle MLP-1. youtube.com/watch?v=1Gcn-5nZKwk

EM-1 is using the MLP originally designed for Ares I, but heavily modified for SLS Block I.

Its not yet decided if EM-2 will use a new MLP.
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Offline Zed_Noir

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Love this quote from Gen. Hyten, “I’m worried about the future. Somehow this country lost the ability to go fast. I don’t know how that happened,” he said. “We take four years to study a problem before we do anything. We do four years of risk reduction on technologies we built 50 years ago.”

http://spacenews.com/battle-brewing-in-the-pentagon-over-military-space-investments/

Pretty much sums up the entirety of the SLS program. I'd de-manifest EC from SLS at this point. NG, Vulcan, Block5 based FH, BFR(?)....
So, built a mobile launcher for Ares X-1, built a mobile launcher for EM-1, and now going to build another for EM-2. 
Even the mobile launchers are expendable.

Ares I-X used the Space Shuttle MLP-1. youtube.com/watch?v=1Gcn-5nZKwk

EM-1 is using the MLP originally designed for Ares I, but heavily modified for SLS Block I.

Its not yet decided if EM-2 will use a new MLP.

IMO building a new Block 1B MLP will not be a lot more expensive than refitting the Block 1 MLP. Both options will be over $100M in my estimation.

Total launch cost with moving the EC to another LV will be roughly the same cost as modifying the current MLP or building a new MLP. To say nothing about $1B+ price tag of the SLS Block 1B in it's inaugural flight.

edit - typo
 


« Last Edit: 12/06/2017 04:54 PM by Zed_Noir »

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http://spacenews.com/nasa-budget-proposal-continues-debate-on-when-and-how-to-launch-europa-clipper/

NASA is study two launch version
one with ULA Atlas V and Gravitational Swing by maneuver for $432 million
other SLS direct to Jupiter for around $600 million

now Capitol Hill is questioning the Europa Clipper budget, special the use of SLS in june 2022


Hey, NASA
you look like intelligent organisation
you look like someone who would be interested in a bargain.
Wanna buy this rocket, NASA ?*
just $150-90 million launch cost and bring space probe direct to destinations, no need for Gravitational Swing by maneuver 




* modified text from Lefty the salesman from sesame street   ::)


Offline Jim

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http://spacenews.com/nasa-budget-proposal-continues-debate-on-when-and-how-to-launch-europa-clipper/

NASA is study two launch version
one with ULA Atlas V and Gravitational Swing by maneuver for $432 million
other SLS direct to Jupiter for around $600 million

now Capitol Hill is questioning the Europa Clipper budget, special the use of SLS in june 2022


Hey, NASA
you look like intelligent organisation
you look like someone who would be interested in a bargain.
Wanna buy this rocket, NASA ?*
just $150-90 million launch cost and bring space probe direct to destinations, no need for Gravitational Swing by maneuver 


not a viable candidate

Offline whatever11235

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not a viable candidate

Can you please expand on this (I assume you are talking about FH)? Not viable direct or at all? Why? What about Atlas V (can Atlas V 552 do direct?)?

Online AncientU

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not a viable candidate

Can you please expand on this (I assume you are talking about FH)? Not viable direct or at all? Why? What about Atlas V (can Atlas V 552 do direct?)?

Because it isn't certified for that class of payload (like SLS is).

https://forum.nasaspaceflight.com/index.php?topic=38021.msg1793327#msg1793327
« Last Edit: 02/26/2018 05:18 PM by AncientU »
"If we shared everything [we are working on] people would think we are insane!"
-- SpaceX friend of mlindner

Offline llanitedave

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That's a fairly loose usage of the word "viable".
"I've just abducted an alien -- now what?"

Offline MaxTeranous

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Pretty sure they could manage to certify it given 4 years notice

Offline Jim

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And, there is not just risk Class A certification, it is also nuclear certification.

Offline UltraViolet9

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And, there is not just risk Class A certification, it is also nuclear certification.

Launches of nuclear materials aren't so much certified as approved on a case-by-case basis by the executive.

Specifically, for NASA missions involving launch of nuclear materials, NASA and DOE spends some years preparing a risk analysis.  This analysis is then reviewed by an Interagency Nuclear Safety Review Panel (INSRP) representing more agencies than NASA and DOE.  The INSRP then forwards a recommendation to the White House, which approves or disapproves the launch.

I was involved in the White House review of the INSRP recommendation for the Cassini launch, described in this press release:

https://www.jpl.nasa.gov/releases/97/casok.html

Google "INSRP" for more.

Offline Sam Ho

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not a viable candidate

Can you please expand on this (I assume you are talking about FH)? Not viable direct or at all? Why? What about Atlas V (can Atlas V 552 do direct?)?
Atlas V 552 will have lower performance than 551 for high-energy (anything except LEO) missions.

The notional Atlas V 551 mission is a VEEGA trajectory of 6 years duration, compared to a 3 year direct mission.

Offline Jim

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And, there is not just risk Class A certification, it is also nuclear certification.

Launches of nuclear materials aren't so much certified as approved on a case-by-case basis by the executive.

Specifically, for NASA missions involving launch of nuclear materials, NASA and DOE spends some years preparing a risk analysis.  This analysis is then reviewed by an Interagency Nuclear Safety Review Panel (INSRP) representing more agencies than NASA and DOE.  The INSRP then forwards a recommendation to the White House, which approves or disapproves the launch.

I was involved in the White House review of the INSRP recommendation for the Cassini launch, described in this press release:

https://www.jpl.nasa.gov/releases/97/casok.html

Google "INSRP" for more.


yes, I know and I supported INSRP for MER and MSL.  The analysis has been done for Atlas V (twice and will be for a third time) and hence it is "certified"

Offline mike robel

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Just being stupid here, how can SLS be certified if the first one has not been produced and/or flown?

Online Lars-J

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Just being stupid here, how can SLS be certified if the first one has not been produced and/or flown?

That's what happens when an organization certifies its own work.  :)  No, it doesn't make sense. The argument would be that they have more insight into their own development, but that does not preclude them from having large blind spots about issues that would effect SLS safety and reliability.
« Last Edit: 03/01/2018 06:00 PM by Lars-J »

Offline yg1968

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NASA no longer seeking to develop second mobile launcher for SLS:

http://spacenews.com/nasa-no-longer-seeking-to-develop-second-mobile-launcher-for-sls/

So does that mean that the Atlas V wins by default for the Europa Clipper mission?

Offline UltraViolet9

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yes, I know and I supported INSRP for MER and MSL.  The analysis has been done for Atlas V (twice and will be for a third time) and hence it is "certified"

Using the exact same A5 (or other LV) configuration may save some analysis on the launch side.

But unless the s/c are exact duplicates launching from the same location on the same trajectory under the same conditions -- and those factors are never identical -- the nuclear and health analysis is always unique to that mission and launch.

Just because a LV configuration launched a short-lived rover with RHUs a couple years ago does _not_ mean that the same LV configuration is "certified" (or cleared, endorsed, etc.) to launch a long-lived rover with RTGs now (for example).

The health risks of those nuclear missions to the population are different, regardless of whether the LV failure modes and probabilities are the same.
« Last Edit: 03/01/2018 09:12 PM by UltraViolet9 »

Offline woods170

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NASA no longer seeking to develop second mobile launcher for SLS:

http://spacenews.com/nasa-no-longer-seeking-to-develop-second-mobile-launcher-for-sls/

So does that mean that the Atlas V wins by default for the Europa Clipper mission?

Not necessarily. It will be dependent on several factors:
- US Congress being adamant on using SLS to launch Europa Clipper
- Development of Europa Clipper being delayed to such an extent that the launch date is well beyond the completion of the EM-2 mods to the ML.

Both scenarios are IMO highly likely.

Offline Jim

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1.  Using the exact same A5 (or other LV) configuration may save some analysis on the launch side.

2. But unless the s/c are exact duplicates launching from the same location on the same trajectory under the same conditions -- and those factors are never identical -- the nuclear and health analysis is always unique to that mission and launch.

3.  Just because a LV configuration launched a short-lived rover with RHUs a couple years ago does _not_ mean that the same LV configuration is "certified" (or cleared, endorsed, etc.) to launch a long-lived rover with RTGs now (for example).

1.  It saves a lot from the LV POV

2.  MSL and Mars 2020 are.

3.  Never said they were.  But it wasn't MER, it was Pluto New Horizons that did a lot of the leg work for MSL.
« Last Edit: 03/02/2018 12:26 PM by Jim »

Offline Markstark

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Second mobile launcher spotted in new omnibus bill

Quote
Provided further, That $895,000,000 shall be for Exploration Ground Systems, including $350,000,000 for a second mobile launch platform and associated SLS activities

Link to bill here: https://t.co/qQ4xfept0G
« Last Edit: 03/22/2018 02:44 AM by Markstark »

Offline Bananas_on_Mars

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It's interesting they spent more than 800 Mio. $ in refurbishing an existing MLP, while a new one is estimated to cost 350 Mio. $....

What a crap.

Offline su27k

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It's interesting they spent more than 800 Mio. $ in refurbishing an existing MLP, while a new one is estimated to cost 350 Mio. $....

Well they originally thought modifying the existing ML would only cost $54 million....

Offline russianhalo117

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It's interesting they spent more than 800 Mio. $ in refurbishing an existing MLP, while a new one is estimated to cost 350 Mio. $....

Well they originally thought modifying the existing ML would only cost $54 million....
That was when SLS was to use the constellation programmes umbilical arms which were still in testing at the time. One of the main factors other than change of launch vehicle: price and mass went up with the switch from gravity arms to swing arms.
« Last Edit: 03/22/2018 09:41 PM by russianhalo117 »