Author Topic: Europa Clipper’s launch date dependent on SLS Mobile Launcher readiness  (Read 7438 times)

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 »

Online 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)"
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Offline 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.

Online 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.

Offline whitelancer64

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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Online 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

Online 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.