Quote from: TrevorMonty on 02/11/2018 12:02 pmQuote from: alexterrell on 02/11/2018 07:40 amAnd what does SLS do that can't be done with 2 or 3 Falcon Heavy launches? No single module for space exploration needs to mass more than 60 tons. SLS is designed for delivering large payloads to BLEO not LEO. You need to compare FH BLEO capabilities with SLS not its LEO.SLS can deliver 25t Orion and crew to DSG in single launch. When FH can do this in single launch then there is case for replacing SLS.To DSG that doesn’t exist and isn’t paid for, and without a proper budget uplift cant afford to be paid for without cancelling some big line item (like SLS)
Quote from: alexterrell on 02/11/2018 07:40 amAnd what does SLS do that can't be done with 2 or 3 Falcon Heavy launches? No single module for space exploration needs to mass more than 60 tons. SLS is designed for delivering large payloads to BLEO not LEO. You need to compare FH BLEO capabilities with SLS not its LEO.SLS can deliver 25t Orion and crew to DSG in single launch. When FH can do this in single launch then there is case for replacing SLS.
And what does SLS do that can't be done with 2 or 3 Falcon Heavy launches? No single module for space exploration needs to mass more than 60 tons.
Huh, I also skipped the last part... Replace SRBs, replace engines... okay.
But a reusable stage also needs to be able to land. It needs legs to do so. Either SpaceX or Blue Origin would be the logical source for these.
It would be useful to see a price table: - Falcon 9, Falcon Heavy- Reusable Mode with new boosters, with used once boosters, with used twice boosters- Expendable Mode with new boosters, with used boosters, with used twice boostersAnyway that is beside the point of article. NASA has spent $10 billion on their Heavy Lift Rocket (and another $6 billion on Orion). I'm not sure what the latest cost estimates are but this says a target is $500 million per launch, yo make one flight per year: http://www.nbcnews.com/id/49019843/ns/technology_and_science-space/#.UFIyOxii5i4 That is probably a gross under-estimate - can NASA really maintain the systems and capability for one launch per year at less than $1 billion per year?And what does SLS do that can't be done with 2 or 3 Falcon Heavy launches? No single module for space exploration needs to mass more than 60 tons. The only reputed benefit over Falcon Heavy was the wider payload fairing, which might be useful for Mars entry heat shields. (Or I could see it being an advantage for large solar arrays which can't be packed so tightly). New Glenn might over come that issue. So with hindsight, SLS should have been cancelled years ago, and the $10 billion spent on an upper stage rocket, or a space tug, or electric space tug. Orion could still be useful - and maybe a tender put out for a commercial heavy lift vehicle to carry it. Then there might be a choice of SpaceX or Boeing or New Glenn for heavy lift packages, and NASA could get completely out of the launch business and focus on space exploration. Moving forward, can the politicians who have wasted the SLS money pay for it out their pockets?SLS will now be completed, and have a test flight and a ceremonial flight. But then what? Every time NASA has a mission, manned or unmanned, they say it'll cost $1 billion to launch on SLS, or $180 million on Falcon Heavy. How does it work in NASA - does the top mandate the launch vehicle for every mission? Perhaps they will be able to come up with a compromise. Falcon Heavy launches the fuel, and SLS launches the mission. But with that architecture, you don't need Block 2 in that case. New Glenn might make it look worse for NASA. If there are two rockets able to lift >45 tons, at a fraction of the cost of SLS, who is going to be interested in using SLS?
The SLS will continue development, which would only make sense given that nearly all the flight hardware has been made for EM-1, and flight hardware is already in process for EM-2
Quote from: MATTBLAK on 02/07/2018 10:14 pmIt would be a Kerbal Kludge; but an SLS using 4x Falcon 9 Block 5's as strap on, flyback boosters would have extraordinary capability. Hey, Dr Steve Pietrobon; have at it! Each F9 is roughly an F-1 engine, so yeah that should work quite well. Haven't got the time now to do that though.Back on topic. With SpaceX cancelling the Lunar and Mars Dragon 2 missions to concentrate on BFR, I believe that has given SLS a lifeline for now. I believe BFR will take much longer than expected, more like 10 years than five. I think a Dragon 2 going around the Moon before Orion had a good chance of killing SLS.
It would be a Kerbal Kludge; but an SLS using 4x Falcon 9 Block 5's as strap on, flyback boosters would have extraordinary capability. Hey, Dr Steve Pietrobon; have at it!
Quote from: Steven Pietrobon on 02/08/2018 06:53 amQuote from: MATTBLAK on 02/07/2018 10:14 pmIt would be a Kerbal Kludge; but an SLS using 4x Falcon 9 Block 5's as strap on, flyback boosters would have extraordinary capability. Hey, Dr Steve Pietrobon; have at it! Each F9 is roughly an F-1 engine, so yeah that should work quite well. Haven't got the time now to do that though.Back on topic. With SpaceX cancelling the Lunar and Mars Dragon 2 missions to concentrate on BFR, I believe that has given SLS a lifeline for now. I believe BFR will take much longer than expected, more like 10 years than five. I think a Dragon 2 going around the Moon before Orion had a good chance of killing SLS.BO can speed up the killing of SLS by announcing NA as an alternative to SLS for NASA. No doubt NA will have more capability than SLS at a cost comparable to BFR. Absolutely no need for SLS when both BFR and NA are in service. Could get up to around 50 launches of a mix of BFR and NA for the cost of a single SLS launch. The economics just totally stack up against SLS.
No direct impact, but FH in many ways cleared the way for BFR, which will have big impact on SLS. Although just goes by some of the comments in this thread I wonder if even BFR can kill SLS, here's some of the arguments I predict we'll see when BFR flies:1. BFR and SLS can compliment each other, why can't we have both? 2. BFR can't launch Orion, so SLS is still needed3. SLS can send 30t+ to TLI in one launch, BFR couldn't, so SLS is superior!4. No impact to SLS, remember BFR hasn't just come to the scene, it's x years late already...5. But we have invested so many billions into SLS, it has hardware, we can't just cancel it6. BFR hasn't demonstrated x number of flights per year, it's still powerpoint!Now try replacing FH/BFR with Starship Enterprise, and most of the arguments still work, what does this tell you...
1. BFR and NA replace SLS because SLS is so dammed expensive.2. BO designs NA to launch Orion as a payload option so SLS not needed.3. NA may be superior to SLS for TLI.4. SLS can no way compete with BFR and NA forcing it's cancellation.5. Just cancel SLS, give it up as a bad job to stop further money bleeding and hand over funding for BFR and NA dev.6. US of BFR may start testing by the time EM-1 launches.So all in all SLS needs to be cancelled now to stop billions more $ being wasted.
Quote from: DJPledger on 02/12/2018 06:25 pm1. BFR and NA replace SLS because SLS is so dammed expensive.2. BO designs NA to launch Orion as a payload option so SLS not needed.3. NA may be superior to SLS for TLI.4. SLS can no way compete with BFR and NA forcing it's cancellation.5. Just cancel SLS, give it up as a bad job to stop further money bleeding and hand over funding for BFR and NA dev.6. US of BFR may start testing by the time EM-1 launches.So all in all SLS needs to be cancelled now to stop billions more $ being wasted.Unfortunately, SLS is doing precisely what it was intended to do. Spread lots of pork around to lobbyists and constituents. It's not called the Senate Launch System for nothing, and as long as the money keeps flowing, the project will continue, launch or not.
Perhaps Musk and Bezos should get together and force NASA to cancel SLS and to fund their HLV systems.
OK, let's paraphrase the question.Could a rocket (such as SLS) continue its existence if her direct competitors offer cheaper options?Could such a rocket exist and fly, even if it has limited use (i.e. missions to lunar orbit) and no commercial launches?The answer should be a theoretical yes. But could it be, in this specific case?
Quote from: RDoc on 02/12/2018 06:38 pmQuote from: DJPledger on 02/12/2018 06:25 pm1. BFR and NA replace SLS because SLS is so dammed expensive.2. BO designs NA to launch Orion as a payload option so SLS not needed.3. NA may be superior to SLS for TLI.4. SLS can no way compete with BFR and NA forcing it's cancellation.5. Just cancel SLS, give it up as a bad job to stop further money bleeding and hand over funding for BFR and NA dev.6. US of BFR may start testing by the time EM-1 launches.So all in all SLS needs to be cancelled now to stop billions more $ being wasted.Unfortunately, SLS is doing precisely what it was intended to do. Spread lots of pork around to lobbyists and constituents. It's not called the Senate Launch System for nothing, and as long as the money keeps flowing, the project will continue, launch or not.Perhaps Musk and Bezos should get together and force NASA to cancel SLS and to fund their HLV systems.