Author Topic: SLS Flexibility: Exploration roadmap focus taking center stage (Read 86185 times)

robertross · « **Reply #20 on:** 10/26/2011 01:45 am »

Quote from: clongton on 10/25/2011 11:53 pm

Postponing the 130 tonne vehicle for a decade or 2 is, in my opinion, a really good idea. And if they do that then they:

(1) don't have to stretch the tank,
(2) don't need the 5th center SSME and
(3) can leave out the center segment of the 5-segment booster and fly it with just 4 segments and 3 SSME's.

Leave the TS configured for 4 SSME's but when flying without the upper stage and only 3 SSME's it will easily lift 70 tonnes to LEO - (*plus* ) - and will easily go to 100 tons by adding an upper stage and the 4th SSME or the center segment and an SSME. Keep the stretched tank, bigger SRB and extra SSME for when we really need to lift 130 tonnes from the ground, which, if the depots are brought on line, could be decades. This would save a *lot* of money that could be redirected to payload development, or maybe even a (gasp) "lander".

Concur.

Propellant depots can really be a game changer for some missions, and I personally don't beleive they need all that extra performance from the vehicle, only its fairing size.

Khadgars · « **Reply #21 on:** 10/26/2011 02:18 am »

Quote from: Chris Bergin on 10/25/2011 11:11 pm

Quote from: Khadgars on 10/25/2011 10:32 pm
Great Article Chris! Lunar First is really intriguing as part of a larger, flexible BEO path. Does Lunar First require additional funding or can it fit within current budgets?

Thanks!

I really do not know. I've always "avoided" dollar amounts, partly because the documentation we gain doesn't contain numbers (if it did, it might be heavily restricted too - so it's always interesting when some sites say there's no money, meaning they either have content they shouldn't or are assuming it), but they have a projection of funding and they can mix and match the best roadmap from that - as is being done right now.

You did see a potential future get-well added to the article, which sounded a bit op-ed, but was actually mentioned to me, which was to forget about the 130mt. SLS Block 1 and 1A brings a lot of capability to the table, and one needs to consider if having that extra 25mt is really worth what it'd cost to have 130mt with all its whistles and bells - especially IF it's stretching the schedule for the flagship BEO missions.

Awesome, I wasn't aware they could stretch Black 1 into 105mt. That seems to make so much more sense and would save a lot of money. I'm curious how that conflicts with what Congress has mandated?

I don't know if I'm naive, but I get the distinct feeling that NASA this time around is a lot more in tune with reality and are really trying to create something great within the budget they have.

I'm also pretty excited that manned lunar fly-by before end of decade set in stone!

Patchouli · « **Reply #22 on:** 10/26/2011 02:37 am »

Quote from: robertross on 10/26/2011 01:45 am

[
Concur.

Propellant depots can really be a game changer for some missions, and I personally don't beleive they need all that extra performance from the vehicle, only its fairing size.

To do a human mission to Mars you end up having to develop much of the technology needed for propellant depot anyway.
For example even a fast mission needs zero boil off and storage of cryogenic propellants for 400+ days.

I think it makes sense to have a depot be part of the architecture from the start.

spectre9 · « **Reply #23 on:** 10/26/2011 04:01 am »

Really enjoyed the article thanks.

I'm having to read many of the older linked stories to keep up with the development but it's all good. I'm learning lots.

Robert Thompson · « **Reply #24 on:** 10/26/2011 04:59 am »

First light at the end of a tunnel.

Jason1701 · « **Reply #25 on:** 10/26/2011 05:08 am »

Presentation said that 130 mT vehicle would fly with 3 RS-25s. Is that right? I thought the final evolved vehicle would use 5.

Carl G · « **Reply #26 on:** 10/26/2011 05:46 am »

Quote from: Jason1701 on 10/26/2011 05:08 am

Presentation said that 130 mT vehicle would fly with 3 RS-25s. Is that right? I thought the final evolved vehicle would use 5.

Yes, 5.

Steven Pietrobon · « **Reply #27 on:** 10/26/2011 06:14 am »

Good to see that NASA is using the correct abbreviation for 1000 kg = 1 tonne (t). An mt (millitonne = 1 kg), Mt (megatonne = 1,000,000,000 kg), mT (milli Tesla = 0.001 T) and MT (mega Tesla = 1,000,000 T) are all incorrect! :-)

neilh · « **Reply #28 on:** 10/26/2011 06:42 am »

Great article, it's good to see that propellant depots are in the solution space.

Proponent · « **Reply #29 on:** 10/26/2011 06:49 am »

Quote from: Steven Pietrobon on 10/26/2011 06:14 am

Good to see that NASA is using the correct abbreviation for 1000 kg = 1 tonne (t). An mt (millitonne = 1 kg), Mt (megatonne = 1,000,000,000 kg), mT (milli Tesla = 0.001 T) and MT (mega Tesla = 1,000,000 T) are all incorrect! :-)

Thanks for pointing this out; it makes me happy.

Nitpick: SI units (though not the symbols for them) are in lower case by default, even when derived from people's names. Thus the SI unit of magnetic induction is the tesla, and million of them make a megatesla.

93143 · « **Reply #30 on:** 10/26/2011 07:00 am »

Wait, wait - "future core stage engine"? Are they just talking about the RS-25E?

Ben the Space Brit · « **Reply #31 on:** 10/26/2011 10:21 am »

It's an interesting article Chris. It does emphasise the degree to which SLS and the utilisation therefore is, to quote a certain Vampire Slayer, "not cookies yet, still just dough". Still, with a first crewed flight not for seven years, minimum, I think NASA can afford the time to sit down and try to get it right.

A prediction: the crewed lunar flyby/orbiter will be re-christened SLS-3 and SLS-2 will become a LEO test of MPCV with ballast in place of the iCPS. It's the sort of intermediate test step that I imagine the AO will feel is prudent.

There might also be a rendezvous with ISS, depending on the timing and whether the station is still in use at that time. I'd also like to see a cargo/crew LOR-based dual MPCV mission.

[edit]
Sorry, I still don't like the Block-I PLF. I'd be a lot happier if they just used the block-II PLF and cut the nose off to make room for the MPCV. It would probably save time and money.

Space101 · « **Reply #32 on:** 10/26/2011 11:39 am »

Enjoying the progress they are making already!

baldusi · « **Reply #33 on:** 10/26/2011 12:13 pm »

So. if no 130t for a while, and the J-2X is way too powerful for the CPS. It might be possible that they develop it, mothballed it, and stays that way for decades?

jtrame · « **Reply #34 on:** 10/26/2011 12:52 pm »

Exciting stuff. Can't wait to see the R-25s fly again.

Won't they need a habitation module of some kind to do the deep space? Seems unreasonable to make a long voyage in the Orion itself.

yamato · « **Reply #35 on:** 10/26/2011 12:58 pm »

MPLM Leonardo, for example?

HappyMartian · « **Reply #36 on:** 10/26/2011 01:28 pm »

Quote from: robertross on 10/26/2011 01:45 am

Quote from: clongton on 10/25/2011 11:53 pm
Postponing the 130 tonne vehicle for a decade or 2 is, in my opinion, a really good idea. And if they do that then they:

(1) don't have to stretch the tank,
(2) don't need the 5th center SSME and
(3) can leave out the center segment of the 5-segment booster and fly it with just 4 segments and 3 SSME's.

Leave the TS configured for 4 SSME's but when flying without the upper stage and only 3 SSME's it will easily lift 70 tonnes to LEO - (*plus* ) - and will easily go to 100 tons by adding an upper stage and the 4th SSME or the center segment and an SSME. Keep the stretched tank, bigger SRB and extra SSME for when we really need to lift 130 tonnes from the ground, which, if the depots are brought on line, could be decades. This would save a *lot* of money that could be redirected to payload development, or maybe even a (gasp) "lander".

Concur.

Propellant depots can really be a game changer for some missions, and I personally don't beleive they need all that extra performance from the vehicle, only its fairing size.

You mean "lander" as in Lunar Lander? YES! I'll take a dozen of those!

Chris Bergin · « **Reply #37 on:** 10/26/2011 01:30 pm »

Quote from: jtrame on 10/26/2011 12:52 pm

Exciting stuff. Can't wait to see the R-25s fly again.

Won't they need a habitation module of some kind to do the deep space? Seems unreasonable to make a long voyage in the Orion itself.

Welcome to the site's forum

Yes, DSH - Deep Space Hab.

There's references linked in the article, but here's one article (with more links within) giving you an example of DSH involvement:

http://www.nasaspaceflight.com/2011/10/neemo-13-days-underwater-mission-sim-neo-exploration/

jtrame · « **Reply #38 on:** 10/26/2011 01:48 pm »

Welcome to the site's forum

Thanks, I've been reading for a few months. --Jim Trame

Archibald · « **Reply #39 on:** 10/26/2011 02:39 pm »

A L1 depot - what an excellent idea. A very good way of using the SLS large payload. You know what ? once the depot in place at L1, they might realise that it can be used for other destinations than NEOs or lunar surface.

The combination of L1 and prop depots is extremely powerful.