Author Topic: Space Launch System (SLS) Q&A  (Read 15030 times)

Online Chris Bergin

Space Launch System (SLS) Q&A
« on: 11/14/2011 07:00 PM »
As requested a general Q&A thread for SLS.

Resources:

Recent SLS articles (we're the only site covering the vehicle in depth and with this frequence. Yay us ;))
http://www.nasaspaceflight.com/tag/hlv/

SLS/HLV Forum Section:

http://forum.nasaspaceflight.com/index.php?board=37.0

L2 SLS Section (amazingly large for a relatively new vehicle):
http://forum.nasaspaceflight.com/index.php?board=48.0

Offline parham55

Re: Space Launch System (SLS) Q&A
« Reply #1 on: 11/14/2011 09:09 PM »
Has the evacuation plan been looked at?
Will we see slide wire baskets, Ares I style roller-coaster, Apollo era rubber room back in action, and/or something entirely different?

Offline brettreds2k

  • Full Member
  • ****
  • Posts: 714
  • Charlotte, NC
  • Liked: 11
  • Likes Given: 25
Re: Space Launch System (SLS) Q&A
« Reply #2 on: 11/15/2011 02:52 PM »
I do know they are not going with the Roller Coaster style system, that they decided not to go with on the new system.
Brett
www.facebook.com/brett.lowenthal1

Orbiters I have visited in retirement:

[ ] Enterprise
[X] Discovery
[X] Atlantis
[ ] Endeavour

Offline Paper Kosmonaut

  • Full Member
  • *
  • Posts: 117
  • Grunn NL
    • PK's blog
  • Liked: 28
  • Likes Given: 4
Re: Space Launch System (SLS) Q&A
« Reply #3 on: 11/21/2011 05:11 PM »
In most of the available NASA promo material of the new SLS, they show both versions in a kind of Saturn-clad black blocks on white surface appearance. I presume it is just done to win the hearts of all those "I just wanna see them shuttles flying again" people but I think without the tons of black and white paint the payload capacities will increase dramatically. Realistically, will the SLS rockets be pristine white or brown bodied?
PK - dei t dut mout t waiten!

Offline JayP

  • Member
  • Full Member
  • ****
  • Posts: 787
  • Liked: 0
  • Likes Given: 0
Re: Space Launch System (SLS) Q&A
« Reply #4 on: 11/22/2011 12:05 AM »
In most of the available NASA promo material of the new SLS, they show both versions in a kind of Saturn-clad black blocks on white surface appearance. I presume it is just done to win the hearts of all those "I just wanna see them shuttles flying again" people but I think without the tons of black and white paint the payload capacities will increase dramatically. Realistically, will the SLS rockets be pristine white or brown bodied?

The black and white stripes are roll reference marks so that they can tell from tracking camera imagery the roll angle and rate of the vehicle. That trace all the way back to peenemünde and has nothing to do with the appearance of the shuttles.

 It's still to be determined if the tankage will be uncoated SOFI or will require a topcoat.

Offline kevin-rf

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8515
  • Overlooking the path Mary's little Lamb took..
  • Liked: 1026
  • Likes Given: 235
Re: Space Launch System (SLS) Q&A
« Reply #5 on: 11/22/2011 01:39 AM »
Why would it require a top coat? There is nothing below it that can be damaged by falling foam...
If you're happy and you know it,
It's your med's!

Offline RocketmanUS

Re: Space Launch System (SLS) Q&A
« Reply #6 on: 01/24/2012 03:30 AM »
If new SSME's ( or expendable version ) are produced for SLS when will the production start?
Mars and beyond, human exploration
The grass is always greener on the other side. When you stand on top of the hill you see both sides!

Offline wolfpack

  • Full Member
  • ****
  • Posts: 666
  • Wake Forest, NC
  • Liked: 87
  • Likes Given: 2
Re: Space Launch System (SLS) Q&A
« Reply #7 on: 01/25/2012 12:52 PM »
If new SSME's ( or expendable version ) are produced for SLS when will the production start?

Well, if there are 15 SSME's left over from STS, and SLS uses 4 for the first flights, then that's 3 flights at least with the existing stock. First flight 2017, one flight every two years, so add six years = 2024. Maybe they'd want to mix one RS-25E in with the RS-25D's so you might need a flight rated one in 2024. Figure two years lead time, so 2022. That'd be my guess.

Production of non-flight rated, sacrificial offerings to the turbopump and combustion chamber gods would have to occur sometime in this decade.

Offline RocketmanUS

Re: Space Launch System (SLS) Q&A
« Reply #8 on: 01/26/2012 02:56 AM »
If new SSME's ( or expendable version ) are produced for SLS when will the production start?

Well, if there are 15 SSME's left over from STS, and SLS uses 4 for the first flights, then that's 3 flights at least with the existing stock. First flight 2017, one flight every two years, so add six years = 2024. Maybe they'd want to mix one RS-25E in with the RS-25D's so you might need a flight rated one in 2024. Figure two years lead time, so 2022. That'd be my guess.

Production of non-flight rated, sacrificial offerings to the turbopump and combustion chamber gods would have to occur sometime in this decade.
So SSME production would not most likely start until we were within three years of the first SLS block 1A launch?

So most likely there will be no more than three SLS block 1 launches?
How many flight ready 5 segment SRB's will be made?
How hard is it to make more 5 seg SRB's if needed after the first production run for the first few SLS block 1 flights?
Mars and beyond, human exploration
The grass is always greener on the other side. When you stand on top of the hill you see both sides!

Offline 93143

  • Senior Member
  • *****
  • Posts: 3039
  • Liked: 292
  • Likes Given: 1
Re: Space Launch System (SLS) Q&A
« Reply #9 on: 01/26/2012 03:07 AM »
I think without the tons of black and white paint the payload capacities will increase dramatically.

The payload would not be impacted dramatically by paint.  According to Wikipedia, Shuttle saved about 600 lbs after the first couple flights by not painting the tank; SLS probably won't save more than about half a ton.
« Last Edit: 01/26/2012 04:57 AM by 93143 »

Offline wolfpack

  • Full Member
  • ****
  • Posts: 666
  • Wake Forest, NC
  • Liked: 87
  • Likes Given: 2
Re: Space Launch System (SLS) Q&A
« Reply #10 on: 01/26/2012 12:34 PM »

So SSME production would not most likely start until we were within three years of the first SLS block 1A launch?

So most likely there will be no more than three SLS block 1 launches?
How many flight ready 5 segment SRB's will be made?
How hard is it to make more 5 seg SRB's if needed after the first production run for the first few SLS block 1 flights?

Really just guessing based on the 2017 inaugural launch date. I'm sure there's a lot more on L2, but my sub ran out. Didn't Jim say they (NASA) have yet to sign a contract with any manufacturer for SLS? Certainly no one's going to build anything without getting paid for it.
« Last Edit: 01/26/2012 12:35 PM by wolfpack »

Offline Zach121k

  • Member
  • Posts: 7
  • Veteran of 3 Launches, 18 Years+ of obsessing.
  • St. Louis
  • Liked: 0
  • Likes Given: 3
Re: Space Launch System (SLS) Q&A
« Reply #11 on: 09/17/2013 05:03 PM »
A couple of days ago, my brother and I, both avid nerds and space obsessed, were debating on the Dual-Launch profile of an SLS Moon landing. Our question was, Wouldn't it be more economically sound to just have kept with the Ares 1 and V, possibly IV, for a dual launch, instead of launching two SLS Heavy Lifters...?
Bragging Rights: Can Successfully Land A Shuttle at the KSC Visitor Center.... Knows too many buttons in the cockpits. Member of the FTC 5095 Team.

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 31294
  • Cape Canaveral Spaceport
  • Liked: 9578
  • Likes Given: 299
Re: Space Launch System (SLS) Q&A
« Reply #12 on: 09/17/2013 05:30 PM »
A couple of days ago, my brother and I, both avid nerds and space obsessed, were debating on the Dual-Launch profile of an SLS Moon landing. Our question was, Wouldn't it be more economically sound to just have kept with the Ares 1 and V, possibly IV, for a dual launch, instead of launching two SLS Heavy Lifters...?

Trick question.  The answer is neither.   
But two launches of a common vehicle is better than two launches of dissimilar vehicles, which would have higher costs infrastructure.

Offline Zach121k

  • Member
  • Posts: 7
  • Veteran of 3 Launches, 18 Years+ of obsessing.
  • St. Louis
  • Liked: 0
  • Likes Given: 3
Re: Space Launch System (SLS) Q&A
« Reply #13 on: 09/18/2013 03:49 PM »
That makes sense! A small infrastructure would be easier.
Bragging Rights: Can Successfully Land A Shuttle at the KSC Visitor Center.... Knows too many buttons in the cockpits. Member of the FTC 5095 Team.

Offline andreaITA

  • Member
  • Posts: 7
  • Italy
  • Liked: 0
  • Likes Given: 0
Re: Space Launch System (SLS) Q&A
« Reply #14 on: 03/30/2015 03:58 PM »
Can someone please tell me how many and what kind of layers the sls core stage is made of?
 In particular I want to know what role has the intertank and if there is any particular external fairing/bulkhead or metal structure that take care of all the loads.
« Last Edit: 03/30/2015 04:08 PM by andreaITA »

Offline Darren_Hensley

  • System Software Engineer, MCTP, NGC, Ft Leavenworth Ks
  • Full Member
  • *
  • Posts: 186
  • Captian(ret) USS Pabilli, Timefleet, UFP-TIC
  • Alamogordo NM
    • H-10-K Enterprises
  • Liked: 10
  • Likes Given: 17
Re: Space Launch System (SLS) Q&A
« Reply #15 on: 01/24/2016 11:17 PM »
What is the dry weight of the core stage, without the engine mass?

or another way to put it

how much for just the empty tanks, skirts, and interstage?
BSNCM Devry, MAITM Webster, MSSS & MSAP SFA
H-10-K Enterprises Gateway Station

Offline Budgie

  • Member
  • Posts: 1
  • Boston, MA
  • Liked: 0
  • Likes Given: 0
Re: Space Launch System (SLS) Q&A
« Reply #16 on: 04/14/2016 11:39 PM »
Hey, all! First post, so hopefully I'm doing this in the right place.

NSF has so much content, so I'm not necessarily asking for a response, but perhaps a link to a thread or a nudge in the right area to search.

1. Why is SLS so expensive, and is it too expensive for what it is, or is it exactly what we should expect for a system of its size and capability?

2. Is there a review or discussion about why we need it, here on NSF (even L2) or on the internet (the more recent the better)? I am a firm believer that SLS is the right way to go for NASA for BEO exploration, but I would like to have some more facts or the opinions of those more knowledgeable than me to back this up.

Thanks!
« Last Edit: 04/14/2016 11:40 PM by Budgie »

Offline rocx

  • Full Member
  • ***
  • Posts: 384
  • NL
  • Liked: 263
  • Likes Given: 145
Re: Space Launch System (SLS) Q&A
« Reply #17 on: 04/15/2016 10:14 AM »
Hello Budgie,

Those two questions have started many threads, and caused even more threads to be locked. I'll try to limit myself to answers that most commenters here would agree on.

1. Big rockets, historically, have been very expensive. There is not much to compare with, and the full costs for Saturn V and especially Energia are hard to find, but it is many billions of dollars. On the one hand building something large means that existing facilities may not be adequate, so you have to build new factories/test stands/manufacturing tools/transport infrastructure. On the other hand there are fewer launches to spread the development costs.

For SLS specifically the first argument was supposed to be invalid, because the tools and infrastructure from the Space Shuttle supply chains are reused. The amount of reuse may have been exaggerated, or deciding you are going to reuse the same contractors before starting contract negotiations may have lead to bad deals. There is also a significant group who believe the reuse requirement was only added in to secure employment and contracts for the existing aerospace manufacturers, by the senators and congressmen in whose districts they are located.

2. The two unique qualities of SLS are heavy payload delivery and a very large fairing. In-orbit refueling could reduce the need for the first, in-orbit assembly could be an alternative for the second. But both bring along their own technical challenges which need their own threads or forum sections to discuss.
Any day with a rocket landing is a fantastic day.

Offline Proponent

  • Senior Member
  • *****
  • Posts: 5156
  • Liked: 783
  • Likes Given: 542
Re: Space Launch System (SLS) Q&A
« Reply #18 on: 04/15/2016 11:09 AM »
Hey, all! First post, so hopefully I'm doing this in the right place.

NSF has so much content, so I'm not necessarily asking for a response, but perhaps a link to a thread or a nudge in the right area to search.

1. Why is SLS so expensive, and is it too expensive for what it is, or is it exactly what we should expect for a system of its size and capability?

I'd say it's too expensive for the capability it provides, especially since there is no clear plan for using the capability.  See the critique of SLS's (and Orion's) costs by the Space Access Society attached to this post.

Quote
2. Is there a review or discussion about why we need it, here on NSF (even L2) or on the internet (the more recent the better)? I am a firm believer that SLS is the right way to go for NASA for BEO exploration, but I would like to have some more facts or the opinions of those more knowledgeable than me to back this up.

There's lots and lots of discussion of the topic here and all over the internet.  I think it's very revealing, though, that, to best of my knowledge, there are just two official attempts at justifying SLS.  One is in the Senate authorization act that created and defined  SLS in 2010 (attached).  The senators just said SLS was a good idea without being very specific how they'd come to that conclusion, without saying what alternatives they had considered and without any visible input from technically-qualified experts.

The other attempt at an official justification that I'm aware of was made at a seminar entitled "Removing Barriers to Deep Space Exploration" in November 2013.  A NASA official--I can't remember whether it was Bill Gerstenmeier--pointed to the interest expressed by Dennis Tito's project Inspiration Mars in using an SLS launch as evidence that an SLS-like vehicle really is needed (some discussion here).  This was such an incredibly weak justification that all by itself it's almost enough to convince me that SLS is a bad idea.  I mean, if NASA, wouldn't you think that NASA would rely on its own very capable engineers to assess launch vehicles rather than relying on statements from a very marginal third-party effort?  We don't even know whether Inspiration Mars's interest an an SLS launch might have been entirely motivated by the hope that it could get the launch for free, since it would be SLS's first flight.

Contrast the decision to build SLS with the Apollo mode decision of 1962, when NASA decided to go to the moon with lunar orbit rendezvous rather than with earth orbit rendezvous or with a direct flight to the lunar surface.  Back then, the [ir]engineers[/i] analyzed the options, argued about them, and finally chose lunar orbit rendezvous.  You can read all about it.  The politicians reviewed the decision and could have overturned it, but the didn't.

SLS, in contrast, seems to have been selected by politicians.

By the way, a long ago I opened a thread for studies concluding that SLS-like heavy lifters really are a good idea for exploring beyond Earth orbit.  Nobody's been able to find such a study!  Meanwhile, quite a number of studies have suggested that using smaller launch vehicles would enable more exploration given under realistic budgets

Offline Hog

  • Full Member
  • ****
  • Posts: 1079
  • Woodstock
  • Liked: 245
  • Likes Given: 556
Re: Space Launch System (SLS) Q&A
« Reply #19 on: 04/15/2016 02:28 PM »
If new SSME's ( or expendable version ) are produced for SLS when will the production start?

Well, if there are 15 SSME's left over from STS, and SLS uses 4 for the first flights, then that's 3 flights at least with the existing stock. First flight 2017, one flight every two years, so add six years = 2024. Maybe they'd want to mix one RS-25E in with the RS-25D's so you might need a flight rated one in 2024. Figure two years lead time, so 2022. That'd be my guess.

Production of non-flight rated, sacrificial offerings to the turbopump and combustion chamber gods would have to occur sometime in this decade.
They just built a 16th engine last year from service parts of the STS program.  The newest engine is ME-2063, its sister ME-2062 was built back in 2010.  Neither engine has have been fired yet.  This will occur this year.  Both of these engines are scheduled to be used together on EM-2/SLS-2.
The other 14 Main Engines are veterans all of which have flight time under their belts(or bells).

Here is a video of ME-2063 being built.


Here is a list of the missions that these  engines last flew on. This is copied from another one of my posts, so is not new info to the board.

Block II/RS25D Engines with flight experience (listed with last mission flown)
1)  2044  STS-133
2)  2045  STS-135
3)  2047  STS-135
4)  2048  STS-133
5)  2050  STS-120
6)  2051  STS-132
7)  2052  STS-132
8)  2054  STS-131
9)  2056  STS-121
10) 2057 STS-134
11) 2058 STS-133
12) 2059 STS-134
13) 2060 STS-135
14) 2061 STS-134

Unflown Block II/RS25D engines
15) 2062 (circa 2010 build)
16) 2063 (2015 build)

Development Engines Block II/RS25D (these are the 2 current Development Engines that have been/areto be fired at Stennis.
17) 0525
18) 0528

Here is a graphic showing the RS25 engine assignments for SLS missions 1 through SLS-4
Paul

Tags: