Quote from: whitelancer64 on 02/07/2018 12:55 pm 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-2That's the sunk-cost fallacy in action. The rational question is, is it worth spending another $15-20 billion to fly those missions ($3-4 billion per year times 5ish years), or is it better to pay termination costs and stop now?
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: drunyan8315 on 02/07/2018 09:39 pmHow can one discuss the relative merits of two rocket systems without acknowledging that one is throwaway and the other is reusable? The first SLS is going to go up in 4-5 years and then... it will be vaporized. Then you get to build another one. Because when Falcon Heavy is flown in its partially reusable form (boosters and core recovered), it only gets Atlas 5-53x capability. It is a "heavy lifter" only when it, too, is expended, and even then it falls short of even SLS Block 1. It can't lift Orion beyond low earth orbit in a single launch, so multiple expended Falcon Heavies would be needed. These expendable versions are going to cost substantially more than the numbers everyone sees on the SpaceX web site. That's not to say that Falcon Heavy and other rockets won't be able to play a big role in NASA's deep space program. There should be plenty of opportunities for systems like these. - Ed Kyle
How can one discuss the relative merits of two rocket systems without acknowledging that one is throwaway and the other is reusable? The first SLS is going to go up in 4-5 years and then... it will be vaporized. Then you get to build another one.
And I fail to see why you'd use Orion if you had the option of cheaper and lighter Dragon... the smaller amount of on-board delta-v is compensated for by being lighter.(Unless you put your deep space gateway in, like, a medium lunar orbit. But you shouldn't do that anyway.
Because when Falcon Heavy is flown in its partially reusable form (boosters and core recovered), it only gets Atlas 5-53x capability. It is a "heavy lifter" only when it, too, is expended, and even then it falls short of even SLS Block 1. It can't lift Orion beyond low earth orbit in a single launch, so multiple expended Falcon Heavies would be needed. These expendable versions are going to cost substantially more than the numbers everyone sees on the SpaceX web site. That's not to say that Falcon Heavy and other rockets won't be able to play a big role in NASA's deep space program. There should be plenty of opportunities for systems like these.
Falcon Heavy Expendable: $90M list price, but for purposes of calculations, assume $110M as a penalty price for dropping a recoverable launch vehicle into the ocean.
Quote from: RyanC on 02/09/2018 12:51 amFalcon Heavy Expendable: $90M list price, but for purposes of calculations, assume $110M as a penalty price for dropping a recoverable launch vehicle into the ocean.$90M is the reusable price. Expendable is $270M according to the AST (see page 17 below). Still a lot cheaper per kg (270,000/63.8 = $4,200/kg) than SLS though ($1,000,000/93.1 = $10,740/kg).https://www.faa.gov/about/office_org/headquarters_offices/ast/media/2018_AST_Compendium.pdf
A. Single-launch architectures, which is what Apollo used and what the SLS is.
Multiple launches are not a problem because it is so much cheaper than SLS that you could afford five or six for the price of one SLS launch. You also don't need expendable versions, you simple expend a used stage.
Quote from: Steven Pietrobon on 02/09/2018 04:54 amQuote from: RyanC on 02/09/2018 12:51 amFalcon Heavy Expendable: $90M list price, but for purposes of calculations, assume $110M as a penalty price for dropping a recoverable launch vehicle into the ocean.$90M is the reusable price. Expendable is $270M according to the AST (see page 17 below). Still a lot cheaper per kg (270,000/63.8 = $4,200/kg) than SLS though ($1,000,000/93.1 = $10,740/kg).https://www.faa.gov/about/office_org/headquarters_offices/ast/media/2018_AST_Compendium.pdfI doubt SpaceX's internal costs for FH expendable are anywhere near $270. Bet they're closer to $150m, particularly since they can use end of life cores for the side boosters.
Quote from: Robotbeat on 02/09/2018 01:13 pmQuote from: Steven Pietrobon on 02/09/2018 04:54 amQuote from: RyanC on 02/09/2018 12:51 amFalcon Heavy Expendable: $90M list price, but for purposes of calculations, assume $110M as a penalty price for dropping a recoverable launch vehicle into the ocean.$90M is the reusable price. Expendable is $270M according to the AST (see page 17 below). Still a lot cheaper per kg (270,000/63.8 = $4,200/kg) than SLS though ($1,000,000/93.1 = $10,740/kg).https://www.faa.gov/about/office_org/headquarters_offices/ast/media/2018_AST_Compendium.pdfI doubt SpaceX's internal costs for FH expendable are anywhere near $270. Bet they're closer to $150m, particularly since they can use end of life cores for the side boosters.I am pretty sure, but what matters for competition is not the cost, but the price...
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...
Quote from: Robotbeat on 02/09/2018 01:06 amYou're relying on figures from the KSC ELV performance page, which has figures that are years out of date. For instance, FH can do about 16 tons through trans Mars insertion, which is about c3= 7km^2/s^2 on an *exceptionally* good opportunity. According to KSC's page, FH can only do 10t. So for high energy trajectories, FH can do about 60% better than the KSC page suggests.No, I didn't use the KSC page. I have expendable Falcon Heavy at 16.8 tonnes TMI. SLS Block 1 would be 19+ tonnes, but of course it is only going to fly one trans-lunar mission. For TLI, I show expendable Falcon Heavy at 20+ tonnes and SLS Block 1 at 24.5 tonnes.The real comparison is with SLS Block 1B, which is expected to be 32 and 39 tonnes to TMI/TLI, respectfully. - Ed Kyle
You're relying on figures from the KSC ELV performance page, which has figures that are years out of date. For instance, FH can do about 16 tons through trans Mars insertion, which is about c3= 7km^2/s^2 on an *exceptionally* good opportunity. According to KSC's page, FH can only do 10t. So for high energy trajectories, FH can do about 60% better than the KSC page suggests.