SLS4 RS-25's ($55M each) $220M2 SRB's ($30M each) $60MTank Core $75MAvionics $25M (rad hard, commonality with EUS)= $380M
Quote from: Ronsmytheiii on 01/22/2018 08:11 pmSo was wondering why SLS kept the clean-pad design of the Ares I ML and tower vs moving the FSS to the Pad surface like Shuttle. The clean pad made sense for Ares as you had two separate LVs, but with SLS after EM-1/only Block 1A flight the vehicle should have a fixed height for umbilicals. By removing the Tower from the ML you free up a lot of space and most importantly weight on it.because it would increase pad time. integration off pad with the umbilical tower makes more sense like Atlas V and Falcon 9. The upper stages and spacecraft need to be checked out with the umbilicals. Spacecraft need to be connected to GSE once attached to the rocket.Shuttle umbilicals were at the tail. LH2 vent was the only connection at the pad.
So was wondering why SLS kept the clean-pad design of the Ares I ML and tower vs moving the FSS to the Pad surface like Shuttle. The clean pad made sense for Ares as you had two separate LVs, but with SLS after EM-1/only Block 1A flight the vehicle should have a fixed height for umbilicals. By removing the Tower from the ML you free up a lot of space and most importantly weight on it.
Quote from: oldAtlas_Eguy on 01/21/2018 03:17 pmSLS4 RS-25's ($55M each) $220M2 SRB's ($30M each) $60MTank Core $75MAvionics $25M (rad hard, commonality with EUS)= $380MI forgot to check your estimate on the Tank Core, and that is way off too. As a point of reference, here is what NASA had negotiated as prices for the Shuttle ET & SRM's near the end of the program:External Tank (ET): last contract - $2.94B for 17 units = $173M/eaSolid Rocket Motors (SRM): last contract - $2.4B for 35 refurbished flight sets = $69M/setThat totals to $241.5M for each Shuttle flight, where you are estimating $135M for each SLS flight for the same hardware elements. I think you are off by a significant amount.As for the RS-25, though NASA is using existing engines for the first four flights, it has already awarded a $1.16B pre-production contract to Aerojet Rocketdyne that produces no flight units, but prepares AR to produce flight units. Assuming the SLS flies at least nine times (4 w/existing engines, 5/new engines), that would mean this contract alone would account for $55M of engine cost, and that doesn't count the cost of producing the new engines themselves (which would be a separate contract).Costs do drop over time as more units are produced, but there are limits to how much they can drop.For instance, for the SLS core the cost of the aluminum will not drop below the current market price because the amount of aluminum the SLS uses is not very significant compared to the total market need, so volume purchasing won't matter. And pretty much everything on the SLS is low-volume production, meaning except for the core units that everything else will be produced on production lines that will only run intermittently, which doesn't allow for much cost reduction - even if production is doubled.But just updating the ET and SRM costs to reflect a number I think is more realistic, I come up with:SLS4 RS-25's ($55M each) $220M2 SRB's ($50M each) $100MTank Core $200MAvionics $25M (rad hard, commonality with EUS)= $545MAnd that would just be the piece-part costs, not the final assembled cost. YMMV
Orion atop that vehicle would be estimated at approximately a billion each ($972M per reference below, p31).Assume both missions include Orion (other payloads, if ever funded, won't be cheaper), so baseline is:1 launch per year > $2.465B2 launches per year > $3.13B
A reusable system doesn't make economic sense if it only flies once or twice per year...
Quote from: RonM on 01/23/2018 01:40 pmA reusable system doesn't make economic sense if it only flies once or twice per year......you've got that backwards. The point of the reusable system would be so you can afford to fly more than once or twice a year.The idea was to do something like this during a later refresh of the SLS design, i.e. along with the proposed flyback boosters.And likely the core would land down-range.It costs like a billion dollars to build an SLS. It may make sense to add some auxiliary engines, grid fins, and legs to enable down-range landing and reuse. (Would also need to change the insulation. But the engines and thrust structure and hydraulics, etc, could remain the same.)
Quote from: Robotbeat on 01/24/2018 01:34 amQuote from: RonM on 01/23/2018 01:40 pmA reusable system doesn't make economic sense if it only flies once or twice per year......you've got that backwards. The point of the reusable system would be so you can afford to fly more than once or twice a year.The idea was to do something like this during a later refresh of the SLS design, i.e. along with the proposed flyback boosters.And likely the core would land down-range.It costs like a billion dollars to build an SLS. It may make sense to add some auxiliary engines, grid fins, and legs to enable down-range landing and reuse. (Would also need to change the insulation. But the engines and thrust structure and hydraulics, etc, could remain the same.)But you loose 30-40% of performance. So an SLS 1B at 110mt LEO payload as expendable (being generous) would become a 66-77mt LEO payload. So it's complete reason for being disappears just to be able to have some reusability of the S1 stages.An SLS 2 as reusable would be 80-90mt. So the level of redesign to get back to a performance level of 100mt would require the SLS to be something completely different.
Quote from: oldAtlas_Eguy on 01/24/2018 01:53 amQuote from: Robotbeat on 01/24/2018 01:34 amQuote from: RonM on 01/23/2018 01:40 pmA reusable system doesn't make economic sense if it only flies once or twice per year......you've got that backwards. The point of the reusable system would be so you can afford to fly more than once or twice a year.The idea was to do something like this during a later refresh of the SLS design, i.e. along with the proposed flyback boosters.And likely the core would land down-range.It costs like a billion dollars to build an SLS. It may make sense to add some auxiliary engines, grid fins, and legs to enable down-range landing and reuse. (Would also need to change the insulation. But the engines and thrust structure and hydraulics, etc, could remain the same.)But you loose 30-40% of performance. So an SLS 1B at 110mt LEO payload as expendable (being generous) would become a 66-77mt LEO payload. So it's complete reason for being disappears just to be able to have some reusability of the S1 stages.An SLS 2 as reusable would be 80-90mt. So the level of redesign to get back to a performance level of 100mt would require the SLS to be something completely different.Partially reusable SLS would need liquid boosters that can land downrange, so the payload hit depends mostly on the specs of those boosters. Using New Glenn boosters as LRBs would greatly increase the payload at the same time as allowing recovery. I estimate 136 t to LEO and 53 t to TLI, both with EUS.Without a larger upper stage than EUS I don't think there is any hope of recovering the core stage, but bigger boosters would allow a couple of RS-25s to be removed (saving ~$114M per flight) while still having much greater payload than SLS 1B.
Quote from: envy887 on 01/24/2018 01:20 pmQuote from: oldAtlas_Eguy on 01/24/2018 01:53 amQuote from: Robotbeat on 01/24/2018 01:34 amQuote from: RonM on 01/23/2018 01:40 pmA reusable system doesn't make economic sense if it only flies once or twice per year......you've got that backwards. The point of the reusable system would be so you can afford to fly more than once or twice a year.The idea was to do something like this during a later refresh of the SLS design, i.e. along with the proposed flyback boosters.And likely the core would land down-range.It costs like a billion dollars to build an SLS. It may make sense to add some auxiliary engines, grid fins, and legs to enable down-range landing and reuse. (Would also need to change the insulation. But the engines and thrust structure and hydraulics, etc, could remain the same.)But you loose 30-40% of performance. So an SLS 1B at 110mt LEO payload as expendable (being generous) would become a 66-77mt LEO payload. So it's complete reason for being disappears just to be able to have some reusability of the S1 stages.An SLS 2 as reusable would be 80-90mt. So the level of redesign to get back to a performance level of 100mt would require the SLS to be something completely different.Partially reusable SLS would need liquid boosters that can land downrange, so the payload hit depends mostly on the specs of those boosters. Using New Glenn boosters as LRBs would greatly increase the payload at the same time as allowing recovery. I estimate 136 t to LEO and 53 t to TLI, both with EUS.Without a larger upper stage than EUS I don't think there is any hope of recovering the core stage, but bigger boosters would allow a couple of RS-25s to be removed (saving ~$114M per flight) while still having much greater payload than SLS 1B.Small problem in using 7m diameter NG as boosters. The pad can only handle a vehicle that is 21m wide. 2 7m wide NG boosters and the 8.4m core is 22.4m. It will not fit.
As a cost saving, I don't know at what point SLS could switch to carbon tanks.
It would save a good % of that £200m structure cost.
NASA/Boeing finished successful testing of a 5.5m hydrogen tank under flight loads in 2016.
The research was specifically aimed at lowering costs and improving payloads of SLS class rockets. The production techniques should scale fairly easily to 8.4 meters.
It'll probably be another bit of great work from NASA & partners than doesn't see active service.
If you are going to have a disposable rocket, tanks manufactured mostly by a robot would seem the perfect way to go.https://www.compositesworld.com/articles/nasaboeing-composite-launch-vehicle-fuel-tank-scores-firsts