Quote from: Lars-J on 05/28/2017 07:38 amQuote from: hkultala on 05/28/2017 06:43 amFH(block 5) has capacity of 63.8 tonnes to LEO, and it's quite LEO optimized-launcher.Even with the very badly underpowered upper stage that makes it very bad for LEO maximum payload, SLS block 1 still has more capacity to LEO, payload to higher orbits where the (lack of) thrust in the US means less is much more than with FH.I get what you mean as far as upper stage efficiency... But very badly underpowered is a very poor choice of words. The M1D-Vac (full thrust) is around 8.5 times more powerful than the most powerful RL-10 ever flown. So even with 4 RL-10 on the EUS, the F9 upper stage has more than twice the thrust. No, I think that's what he WAS saying. The SLS was the referent of that pronoun. "Even with (the SLS's) very badly underpowered upper stage, SLS block 1 still has more capacity to LEO."
Quote from: hkultala on 05/28/2017 06:43 amFH(block 5) has capacity of 63.8 tonnes to LEO, and it's quite LEO optimized-launcher.Even with the very badly underpowered upper stage that makes it very bad for LEO maximum payload, SLS block 1 still has more capacity to LEO, payload to higher orbits where the (lack of) thrust in the US means less is much more than with FH.I get what you mean as far as upper stage efficiency... But very badly underpowered is a very poor choice of words. The M1D-Vac (full thrust) is around 8.5 times more powerful than the most powerful RL-10 ever flown. So even with 4 RL-10 on the EUS, the F9 upper stage has more than twice the thrust.
FH(block 5) has capacity of 63.8 tonnes to LEO, and it's quite LEO optimized-launcher.Even with the very badly underpowered upper stage that makes it very bad for LEO maximum payload, SLS block 1 still has more capacity to LEO, payload to higher orbits where the (lack of) thrust in the US means less is much more than with FH.
Quote from: Lars-J on 05/28/2017 07:38 amQuote from: hkultala on 05/28/2017 06:43 amFH(block 5) has capacity of 63.8 tonnes to LEO, and it's quite LEO optimized-launcher.Even with the very badly underpowered upper stage that makes it very bad for LEO maximum payload, SLS block 1 still has more capacity to LEO, payload to higher orbits where the (lack of) thrust in the US means less is much more than with FH.I get what you mean as far as upper stage efficiency... But very badly underpowered is a very poor choice of words. The M1D-Vac (full thrust) is around 8.5 times more powerful than the most powerful RL-10 ever flown. So even with 4 RL-10 on the EUS, the F9 upper stage has more than twice the thrust. SLS block 1 uses ICPS, not falcon upper stage. ICPS (with that single 110kN RL-10) is the very badly underpowered upper stage I was talking about.
If I had the SLS budget to play with,
Quote from: sevenperforce on 05/26/2017 04:44 pmIf I had the SLS budget to play with, I have once suggested using SLS cores as space station habitats. Much like the old Space Ilands group.I was told that it won't work for several reasons such as heat management, wet launch complications and performance.But now theres a group that seriously suggests doing that with centaur and got NASA funding to research into that as a possible gateway technology. so maybe it is actually possible with SLS cores?!?Also, there are those who suggest that it is smart to reuse the booster's engine compartment and have suggested applying HIAD and parachute combo to do that.there are those who plan to recover side boosters too (no link needed here)I suggest that there could be a way in which SLS makes sense - that is if it was designed as follows-Two RTLS advanced boostersSMART style reuse for the core's engine compartmentOn orbit recycle of modified O2 and H2 tanks as habitats for a space station.Space station support systems and modules are launched as cargoI don't know if that can eventually become cheaper than full reuse architecture like ITS, but it has a fair chance, if a big space station is one of the goals. That is because a bigger fraction of what is launched to orbit, stays on orbit.
Constellation was supposed to have us on the Moon today, too.How's that coming?
Even if it doesn't wait, the commercial launchers will be flying before SLS.. Really, who's the one waiting here?
Quote from: AncientU on 05/27/2017 11:18 pmConstellation was supposed to have us on the Moon today, too.How's that coming?It was canceled by President Obama. - Ed Kyle
Quote from: hkultala on 05/28/2017 04:05 pmQuote from: Lars-J on 05/28/2017 07:38 amQuote from: hkultala on 05/28/2017 06:43 amFH(block 5) has capacity of 63.8 tonnes to LEO, and it's quite LEO optimized-launcher.Even with the very badly underpowered upper stage that makes it very bad for LEO maximum payload, SLS block 1 still has more capacity to LEO, payload to higher orbits where the (lack of) thrust in the US means less is much more than with FH.I get what you mean as far as upper stage efficiency... But very badly underpowered is a very poor choice of words. The M1D-Vac (full thrust) is around 8.5 times more powerful than the most powerful RL-10 ever flown. So even with 4 RL-10 on the EUS, the F9 upper stage has more than twice the thrust. SLS block 1 uses ICPS, not falcon upper stage. ICPS (with that single 110kN RL-10) is the very badly underpowered upper stage I was talking about.Being a big fan of parallel staging, I'd be interested to see the ICPS given an optional 2-engine (or even 4-engine) drop skirt a la Saturn S-1D to increase its payload to LEO. Fixes the underpower problem without increasing dry mass in the BLEO stage.That's if it actually was ever going to be used for LEO. But of course it isn't.
If ULA developed ACES, could this 5.5m upper stage be used on SLS to improve payloads? If so, by how much?
So, NASA is supposed to just wait for these proposed launch vehicles to finally appear? Falcon Heavy was supposed to fly in 2013. We still haven't seen this rocket and now it seems we won't see it until next year. When we finally do see it, it still won't match SLS. The company developing Falcon Heavy has suffered two big rocket explosions during the past two years. Is NASA supposed to stop what it is doing and simply trust that SpaceX, Blue Origin (which recently suffered an engine test failure), and the like will actually succeed on their announced schedules, even though they are doing everything for the first time? NASA can't wait for promises when it has the propulsion in hand. The others may eventually catch up - I hope they do - but there is no need to wait for them. - Ed Kyle
Quote from: edkyle99 on 05/27/2017 10:12 pmSo, NASA is supposed to just wait for these proposed launch vehicles to finally appear? Falcon Heavy was supposed to fly in 2013. We still haven't seen this rocket and now it seems we won't see it until next year. When we finally do see it, it still won't match SLS. The company developing Falcon Heavy has suffered two big rocket explosions during the past two years. Is NASA supposed to stop what it is doing and simply trust that SpaceX, Blue Origin (which recently suffered an engine test failure), and the like will actually succeed on their announced schedules, even though they are doing everything for the first time? NASA can't wait for promises when it has the propulsion in hand. The others may eventually catch up - I hope they do - but there is no need to wait for them. - Ed KyleNo, NASA should not wait, it should have done the same as with CRS.
So, NASA is supposed to just wait for these proposed launch vehicles to finally appear? Falcon Heavy was supposed to fly in 2013. We still haven't seen this rocket and now it seems we won't see it until next year. When we finally do see it, it still won't match SLS. The company developing Falcon Heavy has suffered two big rocket explosions during the past two years. Is NASA supposed to stop what it is doing and simply trust that SpaceX, Blue Origin (which recently suffered an engine test failure), and the like will actually succeed on their announced schedules, even though they are doing everything for the first time? NASA can't wait for promises when it has the propulsion in hand.
Quote from: edkyle99 on 05/27/2017 10:12 pmSo, NASA is supposed to just wait for these proposed launch vehicles to finally appear? Falcon Heavy was supposed to fly in 2013. We still haven't seen this rocket and now it seems we won't see it until next year. When we finally do see it, it still won't match SLS. The company developing Falcon Heavy has suffered two big rocket explosions during the past two years. Is NASA supposed to stop what it is doing and simply trust that SpaceX, Blue Origin (which recently suffered an engine test failure), and the like will actually succeed on their announced schedules, even though they are doing everything for the first time? NASA can't wait for promises when it has the propulsion in hand. If SLS was driven by the Cold War or other national imperative, if SLS had a clear exploration goal, deadline, and funding, and if there were not multiple, proven vendors with HLVs coming online in the next half-decade, then yes, NASA should not wait to pursue SLS.But that's not the case. There is no strong exogenous driver for SLS. There is no clear, agreed-to, funded exploration plan. And there are three domestic HLVs from three different vendors close to first flight or under development today (and a fourth ginormous HLV in early design and technology testing). It does not appear that SLS will be operational before or deliver more total tonnage to space over time than these domestic HLVs. But even if that was not the case, the environment is such that a few years of delay or the large opportunity costs imposed by SLS are worth the difference.Good Government 101 tells us that there is a public sector and a private sector and that the government should not try to duplicate in the public sector what industry can deliver from the private sector. National policy should move NASA out of the ETO segment, focus NASA resources on the in-space (transit, EDL, surface) technologies and systems that industry is not pursuing, and leverage and build on the ongoing ETO developments in the private sector.
These are all good points. However, NASA is required by law to build SLS. They are required by law to NOT wait to pursue SLS - it has a specific deadline, which has already passed. And national policy is directed by the President and affirmed and funded by Congress - NASA can only advise both and cannot chose their own way.
National policy should move NASA out of the ETO segment, focus NASA resources on the in-space (transit, EDL, surface) technologies and systems that industry is not pursuing, and leverage and build on the ongoing ETO developments in the private sector.
Good Government 101 tells us that there is a public sector and a private sector and that the government should not try to duplicate in the public sector what industry can deliver from the private sector. National policy should move NASA out of the ETO segment, focus NASA resources on the in-space (transit, EDL, surface) technologies and systems that industry is not pursuing, and leverage and build on the ongoing ETO developments in the private sector.
Quote from: UltraViolet9 on 05/30/2017 08:50 pmGood Government 101 tells us that there is a public sector and a private sector and that the government should not try to duplicate in the public sector what industry can deliver from the private sector. National policy should move NASA out of the ETO segment, focus NASA resources on the in-space (transit, EDL, surface) technologies and systems that industry is not pursuing, and leverage and build on the ongoing ETO developments in the private sector.How long until the same argument is used to say that NASA shouldn't be building any in-space vehicles at all? After all commercial interests might do that on their own as well...
Government helped build the railroads out west by giving land to the railroad companies along the routes.