Author Topic: SLS General Discussion Thread 2  (Read 413805 times)

Offline spacenut

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Re: SLS General Discussion Thread 2
« Reply #980 on: 05/30/2017 05:45 PM »
From what I see the delay's in FH coming on line are that F9 has gone through several upgrades, the launch facilities at 39A were delayed in coming on line, pad 40 has had to be restored for F9 launches, and SpaceX has had to perfect the landings.  All of this takes time, not just the launch vehicle itself. 

With the right adapter, Orion can fit on FH.  They already have a 5m fairing.  FH will also be man rated. 

Atlas can't really do it, Delta IV heavy is hard pressed and not man rated.  That only leaves FH that is soon to be coming on line.  Maybe New Glenn in a few years. 

$1 billion just to launch 4 people into orbit, isn't good for my tax dollars.  Just pay SpaceX to do it cheaper.  Use SLS for deep space probes or 100 ton modules for some type of deep space habitat or Mars vehicle and take 10 years to build it with one launch per year.  Direct sounds better and better from a taxpayers point of view.  Now with rocket re-usability, SLS and even Direct are expensive.  Even if FH has a $300,000 or $400,000 price tag for Orion, it's still far cheaper.  Even at that with full expendable mode version 5 of FH, plus a F9 tanker to refuel the 2nd stage, you could probably throw Orion around the moon cheaper.     
« Last Edit: 05/30/2017 05:47 PM by spacenut »

Offline envy887

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Re: SLS General Discussion Thread 2
« Reply #981 on: 05/30/2017 08:38 PM »
Capsule: 10.4 mT, Service Module: 15.5 mT, SM Propellant: 9.3 mT, LAS: 7.3 mT, 4 Crew + supplies: 1.0 mT. 
Orion Spacecraft Total: 41.8 mT     
...

I don't think this is correct. Orion is intended to have 1250 to 1300 m/s of delta-v plus margins, but this mass total (34.5 t fueled after discarding LAS, and 25.2 t dry) only allows <1000 m/s with 319s specific impulse.

If the fueled mass is 25.2 t after discarding LAS and 15.9 tonnes dry then it has 1440 m/s delta-v. Much more in line with Orion's expected capabilities.

I think the mass of stage adapters and SM fairings is also missing, and has to be accounted for to fly on an EELV class rocket.

Offline woods170

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Re: SLS General Discussion Thread 2
« Reply #982 on: 05/31/2017 08:18 AM »
Capsule: 10.4 mT, Service Module: 15.5 mT, SM Propellant: 9.3 mT, LAS: 7.3 mT, 4 Crew + supplies: 1.0 mT. 
Orion Spacecraft Total: 41.8 mT     
...

I don't think this is correct. Orion is intended to have 1250 to 1300 m/s of delta-v plus margins, but this mass total (34.5 t fueled after discarding LAS, and 25.2 t dry) only allows <1000 m/s with 319s specific impulse.

If the fueled mass is 25.2 t after discarding LAS and 15.9 tonnes dry then it has 1440 m/s delta-v. Much more in line with Orion's expected capabilities.

I think the mass of stage adapters and SM fairings is also missing, and has to be accounted for to fly on an EELV class rocket.
Chuck has the figures for the SM off. It's mass is 15.5 mT INCLUDING propellant. (6.2 mT dry weight).
Fully fueled weight of Orion (with Crew + supplies, but without LAS) ~ 27 mT.
A sub-fueled one with just two Crew members and reduced supplies for short LEO mission weighs approx. 4mT less.

Online TrevorMonty

Re: SLS General Discussion Thread 2
« Reply #983 on: 05/31/2017 03:06 PM »
The FH can only handle payload of around 25mt (see FH thread). The 63mt to LEO is performance figure. Orion needs to go to BLEO, we have CC vehicles for LEO.

BLEO will require US refuelling as mentioned, like it was a simple thing to do. Refuelling a RP1 stage is very complex. Most important thing is US endurance required of tanker and payload US, days if not weeks for tanker. Then there is rendezvous, LOX and RP1 transfer, N gas for thrusters and He for tank pressurization.

US needs additional thrusters rendezvous.

Offline oldAtlas_Eguy

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Re: SLS General Discussion Thread 2
« Reply #984 on: 05/31/2017 03:24 PM »
Capsule: 10.4 mT, Service Module: 15.5 mT, SM Propellant: 9.3 mT, LAS: 7.3 mT, 4 Crew + supplies: 1.0 mT. 
Orion Spacecraft Total: 41.8 mT     
...

I don't think this is correct. Orion is intended to have 1250 to 1300 m/s of delta-v plus margins, but this mass total (34.5 t fueled after discarding LAS, and 25.2 t dry) only allows <1000 m/s with 319s specific impulse.

If the fueled mass is 25.2 t after discarding LAS and 15.9 tonnes dry then it has 1440 m/s delta-v. Much more in line with Orion's expected capabilities.

I think the mass of stage adapters and SM fairings is also missing, and has to be accounted for to fly on an EELV class rocket.
Chuck has the figures for the SM off. It's mass is 15.5 mT INCLUDING propellant. (6.2 mT dry weight).
Fully fueled weight of Orion (with Crew + supplies, but without LAS) ~ 27 mT.
A sub-fueled one with just two Crew members and reduced supplies for short LEO mission weighs approx. 4mT less.
So which of the following stated values for SLS 1B is the right one to use 39.2mt to TLI or 45mt to EM-2. Your values for Orion + SM is 42.5mt. That leaves just 2.5mt for a rideshare payload to EM-2. Something is wrong about these numbers if NASA keeps saying it can launch DSG elemnts with Orion to  a Lunar orbit as long as the DSG element is <10mt.

But this extremely heavy Orion+SM makes the case that the propellant in the SM would be mostly used up to overcome the SLS-1B payload shortfall leaving only enough to do the TEI burn for just the Orion+SM.

So is there some conflict between the planning values and actual capability values?

Re: SLS General Discussion Thread 2
« Reply #985 on: 05/31/2017 04:03 PM »
https://twitter.com/nova_road/status/869943653766180868

Quote
So it turns out there will be crew on SLS/Orion EM-1: Living, breathing plants. They will help study the effects of radiation.

Offline Steven Pietrobon

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Re: SLS General Discussion Thread 2
« Reply #986 on: 06/01/2017 08:14 AM »
So which of the following stated values for SLS 1B is the right one to use 39.2mt to TLI or 45mt to EM-2. Your values for Orion + SM is 42.5mt. That leaves just 2.5mt for a rideshare payload to EM-2. Something is wrong about these numbers if NASA keeps saying it can launch DSG elemnts with Orion to  a Lunar orbit as long as the DSG element is <10mt.

The Boeing Sep. 2013 paper says 39.1 t to TLI for Block IB.
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline AnalogMan

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Re: SLS General Discussion Thread 2
« Reply #987 on: 06/06/2017 09:31 AM »
This seems to have gone missing, so repost.

[... rocket comparison table]

Original post got moved to start a new thread here:
https://forum.nasaspaceflight.com/index.php?topic=43073.0
« Last Edit: 06/06/2017 09:34 AM by AnalogMan »

Offline IanThePineapple

Re: SLS General Discussion Thread 2
« Reply #988 on: 07/12/2017 02:16 AM »
Everyone's talking a lot about EM-1 and EM-2, but where does Europa Clipper fit into the schedule currently? Is it even slated for an SLS launch anymore?

Offline IanThePineapple

Re: SLS General Discussion Thread 2
« Reply #989 on: 07/12/2017 02:19 AM »
Also, we're pretty convinced the SRBs won't be painted (like the Falcon 9 and FH landing legs from those old renders), right?

Offline okan170

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Re: SLS General Discussion Thread 2
« Reply #990 on: 07/12/2017 02:56 AM »
Everyone's talking a lot about EM-1 and EM-2, but where does Europa Clipper fit into the schedule currently? Is it even slated for an SLS launch anymore?

As far as the latest, its still set for SLS launch by law.  There seems to be some hope to fly it before EM-2, but it could also fly after it.

Offline IanThePineapple

Re: SLS General Discussion Thread 2
« Reply #991 on: 07/12/2017 03:16 AM »
Thanks!

Offline Proponent

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Re: SLS General Discussion Thread 2
« Reply #992 on: 07/12/2017 08:53 AM »
Everyone's talking a lot about EM-1 and EM-2, but where does Europa Clipper fit into the schedule currently? Is it even slated for an SLS launch anymore?

As far as the latest, its still set for SLS launch by law.  There seems to be some hope to fly it before EM-2, but it could also fly after it.

It's my understanding that JPL has not yet selected the launch vehicle.  If I am out of date or otherwise wrong, I would very much appreciate a pointer to the correct information.

Another thing that would be interesting to know is the precise legal language connecting SLS with Europa Clipper.  Is is something like the requirement in the 2010 Authorization Act that Shuttle-derived hardware shall be used "to the maximum extent practicable"?  In other words, to what extent has Congress predetermined the conclusions that JPL's engineers will reach?
« Last Edit: 07/12/2017 09:25 AM by Proponent »

Offline Proponent

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Re: SLS General Discussion Thread 2
« Reply #993 on: 07/12/2017 09:21 AM »
However this launch still feels like people were finding something for the SLS to do whilst the Deep Space Habitat modules are developed....
  [Quote truncated by Proponent]

But you will say this no matter what mission is selected for SLS.

It's a perfectly reasonable statement, given that:

1. The mission is being undertaken only after SLS's development has consumed over $10 billion and five years;
2. There has been (correct me if I'm wrong) no consideration of accomplishing the same thing without SLS;
3. A DSH seems reasonable only in the current context: had it been proposed in 2011 as a 15-year-horizon objective for SLS, it would have seemed ridiculous for being so underwhelming.

Offline AnalogMan

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Re: SLS General Discussion Thread 2
« Reply #994 on: 07/12/2017 10:53 AM »
Everyone's talking a lot about EM-1 and EM-2, but where does Europa Clipper fit into the schedule currently? Is it even slated for an SLS launch anymore?

As far as the latest, its still set for SLS launch by law.  There seems to be some hope to fly it before EM-2, but it could also fly after it.

It's my understanding that JPL has not yet selected the launch vehicle.  If I am out of date or otherwise wrong, I would very much appreciate a pointer to the correct information.

Another thing that would be interesting to know is the precise legal language connecting SLS with Europa Clipper.  Is is something like the requirement in the 2010 Authorization Act that Shuttle-derived hardware shall be used "to the maximum extent practicable"?  In other words, to what extent has Congress predetermined the conclusions that JPL's engineers will reach?

H.R. 244 Consolidated Appropriations Act, 2017 became Public Law 115-31 on May 5, 2017.  It contains the following text regarding the Europa Mission under the NASA Science Section (page 78 of the attached bill):

"[] Provided further, That, of the amounts provided, $275,000,000 is for an orbiter and a lander to meet the science goals for the Jupiter Europa mission as outlined in the most recent planetary science decadal survey: Provided further, That the National Aeronautics and Space Administration shall use the Space Launch System as the launch vehicle or vehicles for the Jupiter Europa mission, plan for an orbiter launch no later than 2022 and a lander launch no later than 2024, and include in the fiscal year 2018 budget the 5-year funding profile necessary to achieve these goals."

https://www.congress.gov/115/bills/hr244/BILLS-115hr244enr.pdf

[copy of H.R.244 also attached]

Offline Proponent

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Re: SLS General Discussion Thread 2
« Reply #995 on: 07/12/2017 12:03 PM »
OK, so it sounds like Congress has in fact determined what JPL will conclude.  There isn't even any wiggle room, like "to the extent practicable."

[joke]
Once again, America is very fortunate to have such brilliant and omniscient politicians, capable of performing in-depth technical analyses!  Who needs engineers or scientists!
[/joke]

Offline SweetWater

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Re: SLS General Discussion Thread 2
« Reply #996 on: 07/12/2017 12:56 PM »
OK, so it sounds like Congress has in fact determined what JPL will conclude.  There isn't even any wiggle room, like "to the extent practicable."

[joke]
Once again, America is very fortunate to have such brilliant and omniscient politicians, capable of performing in-depth technical analyses!  Who needs engineers or scientists!
[/joke]

Congressional representatives have to find something to use SLS for if they want to justify keeping it - and the jobs it provides in their districts - in production. The Deep Space Gateway and missions like the Europa orbiter and lander accomplish that goal. To the people doling out the money, IMHO, the engineering and science are secondary considerations (if that).

Offline oldAtlas_Eguy

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Re: SLS General Discussion Thread 2
« Reply #997 on: 07/12/2017 05:26 PM »
OK, so it sounds like Congress has in fact determined what JPL will conclude.  There isn't even any wiggle room, like "to the extent practicable."

[joke]
Once again, America is very fortunate to have such brilliant and omniscient politicians, capable of performing in-depth technical analyses!  Who needs engineers or scientists!
[/joke]

Congressional representatives have to find something to use SLS for if they want to justify keeping it - and the jobs it provides in their districts - in production. The Deep Space Gateway and missions like the Europa orbiter and lander accomplish that goal. To the people doling out the money, IMHO, the engineering and science are secondary considerations (if that).
The leagal wording mixed with reality in the Orion EM-2 scheduling would then create a launch order of
EM-1 NET 2019
EC-1 NET 2022
EM-2 NET 2023
EC-2 NET 2024

But then EM-3 because it now must wait on a new RS-25E engine would have a NET of 2026. At at only 2 engines/yr the rest of the decade unless congress fixes this engine delivery bottleneck with significant funding:
EM-4 NET 2028
with EM-5 NET 2030.

Only a possible 7 total launches before 2030. Unless Congress funds manufacturing upgrades to be able to build them faster. And that effort must start 5-7 years prior to 2024. Which is no latter than the 2019 budget year. In reality they should have already been working on fixing the engine build rate problem.

ADDED:
This is the truly sad part and that is due to build rate limitations causing flight rate limitations and very low usability the cost per flight of SLS alone including all funds spent between 2012 and before 2030 is $4.4B/flight. This is a program period of 18 years.
« Last Edit: 07/12/2017 05:33 PM by oldAtlas_Eguy »

Offline whitelancer64

Re: SLS General Discussion Thread 2
« Reply #998 on: 07/12/2017 05:31 PM »
Also, we're pretty convinced the SRBs won't be painted (like the Falcon 9 and FH landing legs from those old renders), right?

I hope they are painted, at least for the EM-1 mission. I think the SRB swoops look slick.
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Offline Endeavour_01

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Re: SLS General Discussion Thread 2
« Reply #999 on: 07/12/2017 06:36 PM »
However this launch still feels like people were finding something for the SLS to do whilst the Deep Space Habitat modules are developed....
  [Quote truncated by Proponent]

But you will say this no matter what mission is selected for SLS.

It's a perfectly reasonable statement, given that:

1. The mission is being undertaken only after SLS's development has consumed over $10 billion and five years;

This would be true for any SLS mission being considered, hence Khadgar's comment.

Quote
]2. There has been (correct me if I'm wrong) no consideration of accomplishing the same thing without SLS;

Politically there hasn't been much consideration of other launch vehicles. That said there has been consideration by JPL and others. SLS does have distinct advantages in terms of getting the payload to Europa in much less time and is well suited for launching the heavier lander.

Quote
3. A DSH seems reasonable only in the current context: had it been proposed in 2011 as a 15-year-horizon objective for SLS, it would have seemed ridiculous for being so underwhelming.

Because proposing no destination, then half heartedly proposing to go to a NEA, and then proposing ARM was so much more exciting? I would have been thrilled if they had gone with DSG from the get go. It offers the prospect of sustainable lunar orbital and surface missions as well as learning how to be less dependent on Earth for future Mars missions.

I cheer for both NASA and commercial space. For SLS, Orion, Falcon 9, Falcon Heavy, Dragon, Starliner, Cygnus and all the rest!
I was blessed to see the launch of Space Shuttle Endeavour on STS-99. The launch was beyond amazing. My 8-year old mind was blown. I remember the noise and seeing the exhaust pour out of the shuttle as it lifted off. I remember staring and watching it soar while it was visible in the clear blue sky. It was one of the greatest moments of my life and I will never forget it.

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