Quote from: Rocket Science on 12/20/2017 01:43 pmQuote from: envy887 on 12/20/2017 12:59 pmQuote from: brickmack on 12/20/2017 03:59 amQuote from: Patchouli on 12/20/2017 01:48 amNew Glenn has a max thrust 3,850,000lbs which is very close to that of the five segment RSRM which is around 3,600,000lbs.They would stage higher and faster but probably not as much as the Dynetics Pyrios booster would have since they would normally be saving some of the propellant for landing.You probably could deal with it by just throttling back the RS-25s for part of the flight .At shutdown it'll be producing a lot of thrust still (while solids "throttle" almost to zero), unless they shut down all but the center engine or something. This was a problem for all previously-studied liquid boosters, the loads from the boosters pushing on the core stage just before BECO are too high. Even with RSRMV they've already had to alter the core stage throttle profile to mitigate this, but with any liquid option they'll probably have to add a 5th RS-25 to minimize the relative acceleration (and, unless thats coupled with some sort of engine reuse, this only exacerbates the most critical cost and schedule problem of the program)The F-1B only had two throttle settings, and the lowest was 72% of max. And with two off-center engines on Pyrios they could not shut some of them down to "throttle".BE-4 will throttle much lower, somewhere around 30%, and is much more controllable since it's a requirement for landing. If they need to, they can shut down 2, 4 or 6 engines leading up to separation. The extra 80+ seconds of burn time will allow the RS-25s to burn an extra 140 tonnes of fuel, increasing the core stage TWR at booster sep and further reducing the difference in acceleration of the boosters and core.With the relatively slow liftoff (~1.23 TWR at liftoff) and the large mass of the core stage (at staging it will mass 50% more than two NG upper stages), the boosters should be going fairly slow at staging compared to New Glenn, although much faster than RSRMs will be. I figure about 2.3 km/s at booster sep for NG booster SLS, vs 2.5 km/s for NG, vs 1.4 km/s for RSRM boosted SLS.The extra velocity at staging with NG boosters is sufficient to put the entire EUS and Orion in orbit with only a small circularization burn from the EUS (even with downrange recovery of the boosters).Now if we can recover the core main engines in a "pod" as has been studied over the years we will begin to see potentially real cost savings in the out years with a flyback/boostback architecture...This "pod" would be coming back from orbit. Might be a lot cheaper to shorten the core and land it downrange, and use the difference in height to build a large 2nd stage.
Quote from: envy887 on 12/20/2017 12:59 pmQuote from: brickmack on 12/20/2017 03:59 amQuote from: Patchouli on 12/20/2017 01:48 amNew Glenn has a max thrust 3,850,000lbs which is very close to that of the five segment RSRM which is around 3,600,000lbs.They would stage higher and faster but probably not as much as the Dynetics Pyrios booster would have since they would normally be saving some of the propellant for landing.You probably could deal with it by just throttling back the RS-25s for part of the flight .At shutdown it'll be producing a lot of thrust still (while solids "throttle" almost to zero), unless they shut down all but the center engine or something. This was a problem for all previously-studied liquid boosters, the loads from the boosters pushing on the core stage just before BECO are too high. Even with RSRMV they've already had to alter the core stage throttle profile to mitigate this, but with any liquid option they'll probably have to add a 5th RS-25 to minimize the relative acceleration (and, unless thats coupled with some sort of engine reuse, this only exacerbates the most critical cost and schedule problem of the program)The F-1B only had two throttle settings, and the lowest was 72% of max. And with two off-center engines on Pyrios they could not shut some of them down to "throttle".BE-4 will throttle much lower, somewhere around 30%, and is much more controllable since it's a requirement for landing. If they need to, they can shut down 2, 4 or 6 engines leading up to separation. The extra 80+ seconds of burn time will allow the RS-25s to burn an extra 140 tonnes of fuel, increasing the core stage TWR at booster sep and further reducing the difference in acceleration of the boosters and core.With the relatively slow liftoff (~1.23 TWR at liftoff) and the large mass of the core stage (at staging it will mass 50% more than two NG upper stages), the boosters should be going fairly slow at staging compared to New Glenn, although much faster than RSRMs will be. I figure about 2.3 km/s at booster sep for NG booster SLS, vs 2.5 km/s for NG, vs 1.4 km/s for RSRM boosted SLS.The extra velocity at staging with NG boosters is sufficient to put the entire EUS and Orion in orbit with only a small circularization burn from the EUS (even with downrange recovery of the boosters).Now if we can recover the core main engines in a "pod" as has been studied over the years we will begin to see potentially real cost savings in the out years with a flyback/boostback architecture...
Quote from: brickmack on 12/20/2017 03:59 amQuote from: Patchouli on 12/20/2017 01:48 amNew Glenn has a max thrust 3,850,000lbs which is very close to that of the five segment RSRM which is around 3,600,000lbs.They would stage higher and faster but probably not as much as the Dynetics Pyrios booster would have since they would normally be saving some of the propellant for landing.You probably could deal with it by just throttling back the RS-25s for part of the flight .At shutdown it'll be producing a lot of thrust still (while solids "throttle" almost to zero), unless they shut down all but the center engine or something. This was a problem for all previously-studied liquid boosters, the loads from the boosters pushing on the core stage just before BECO are too high. Even with RSRMV they've already had to alter the core stage throttle profile to mitigate this, but with any liquid option they'll probably have to add a 5th RS-25 to minimize the relative acceleration (and, unless thats coupled with some sort of engine reuse, this only exacerbates the most critical cost and schedule problem of the program)The F-1B only had two throttle settings, and the lowest was 72% of max. And with two off-center engines on Pyrios they could not shut some of them down to "throttle".BE-4 will throttle much lower, somewhere around 30%, and is much more controllable since it's a requirement for landing. If they need to, they can shut down 2, 4 or 6 engines leading up to separation. The extra 80+ seconds of burn time will allow the RS-25s to burn an extra 140 tonnes of fuel, increasing the core stage TWR at booster sep and further reducing the difference in acceleration of the boosters and core.With the relatively slow liftoff (~1.23 TWR at liftoff) and the large mass of the core stage (at staging it will mass 50% more than two NG upper stages), the boosters should be going fairly slow at staging compared to New Glenn, although much faster than RSRMs will be. I figure about 2.3 km/s at booster sep for NG booster SLS, vs 2.5 km/s for NG, vs 1.4 km/s for RSRM boosted SLS.The extra velocity at staging with NG boosters is sufficient to put the entire EUS and Orion in orbit with only a small circularization burn from the EUS (even with downrange recovery of the boosters).
Quote from: Patchouli on 12/20/2017 01:48 amNew Glenn has a max thrust 3,850,000lbs which is very close to that of the five segment RSRM which is around 3,600,000lbs.They would stage higher and faster but probably not as much as the Dynetics Pyrios booster would have since they would normally be saving some of the propellant for landing.You probably could deal with it by just throttling back the RS-25s for part of the flight .At shutdown it'll be producing a lot of thrust still (while solids "throttle" almost to zero), unless they shut down all but the center engine or something. This was a problem for all previously-studied liquid boosters, the loads from the boosters pushing on the core stage just before BECO are too high. Even with RSRMV they've already had to alter the core stage throttle profile to mitigate this, but with any liquid option they'll probably have to add a 5th RS-25 to minimize the relative acceleration (and, unless thats coupled with some sort of engine reuse, this only exacerbates the most critical cost and schedule problem of the program)
New Glenn has a max thrust 3,850,000lbs which is very close to that of the five segment RSRM which is around 3,600,000lbs.They would stage higher and faster but probably not as much as the Dynetics Pyrios booster would have since they would normally be saving some of the propellant for landing.You probably could deal with it by just throttling back the RS-25s for part of the flight .
At the low flight rates envisioned for SLS, I suspect that reusability would cost more than it saved.
Quote from: Proponent on 12/20/2017 02:53 pmAt the low flight rates envisioned for SLS, I suspect that reusability would cost more than it saved.Depends how much of it is custom. If Blue is already operating NG as a reusable human-rated vehicle, and already has recovery ships and all the hardware figured out, and the only vehicle change is a custom interstage/nose cone/thrust beam attachment, then it might not be very expensive. Especially considering the huge payload capability upgrade.
Quote from: envy887 on 12/20/2017 05:59 pmQuote from: Proponent on 12/20/2017 02:53 pmAt the low flight rates envisioned for SLS, I suspect that reusability would cost more than it saved.Depends how much of it is custom. If Blue is already operating NG as a reusable human-rated vehicle, and already has recovery ships and all the hardware figured out, and the only vehicle change is a custom interstage/nose cone/thrust beam attachment, then it might not be very expensive. Especially considering the huge payload capability upgrade.But why would Bezos want to help NASA compete against his own rockets that will be both cheaper and have greater lift than SLS?
Bezos avoids overly intrusive NASA involvement like the plague.
Quote from: woods170 on 02/19/2018 06:52 amBezos avoids overly intrusive NASA involvement like the plague.How does this mesh with the BE-3 on EUS study?
Quote from: theinternetftw on 02/21/2018 10:11 amQuote from: woods170 on 02/19/2018 06:52 amBezos avoids overly intrusive NASA involvement like the plague.How does this mesh with the BE-3 on EUS study?BE-3 is an existing engine. NASA can only use it as-is. If NASA wants lotsa changes made to it (for use on EUS) than Bezos will say "No thank you" and move on. That's avoiding overly intrusive NASA involvement right there.Remember, Blue Origin in no way needs additional business for BE-3 to stay in business, courtesy of the very deep pockets of Bezos.
courtesy of the very deep pockets of Bezos.
Quote from: woods170 on 02/21/2018 12:02 pmQuote from: theinternetftw on 02/21/2018 10:11 amQuote from: woods170 on 02/19/2018 06:52 amBezos avoids overly intrusive NASA involvement like the plague.How does this mesh with the BE-3 on EUS study?BE-3 is an existing engine. NASA can only use it as-is. If NASA wants lotsa changes made to it (for use on EUS) than Bezos will say "No thank you" and move on. That's avoiding overly intrusive NASA involvement right there.Remember, Blue Origin in no way needs additional business for BE-3 to stay in business, courtesy of the very deep pockets of Bezos.If BE-4 is going to launch NASA crews on Vulcan there will be some intrusive NASA involvement.
Quote from: woods170 on 02/21/2018 12:02 pmQuote from: theinternetftw on 02/21/2018 10:11 amQuote from: woods170 on 02/19/2018 06:52 amBezos avoids overly intrusive NASA involvement like the plague.How does this mesh with the BE-3 on EUS study?BE-3 is an existing engine. NASA can only use it as-is. If NASA wants lotsa changes made to it (for use on EUS) than Bezos will say "No thank you" and move on. That's avoiding overly intrusive NASA involvement right there.Remember, Blue Origin in no way needs additional business for BE-3 to stay in business, courtesy of the very deep pockets of Bezos.M1-D is an existing engine with thousands (>10,000) of firings and about 500 on orbital launches -- 1 failure, early in these flights.NASA is forcing change.
Quote from: AncientU on 02/21/2018 05:33 pmQuote from: woods170 on 02/21/2018 12:02 pmQuote from: theinternetftw on 02/21/2018 10:11 amQuote from: woods170 on 02/19/2018 06:52 amBezos avoids overly intrusive NASA involvement like the plague.How does this mesh with the BE-3 on EUS study?BE-3 is an existing engine. NASA can only use it as-is. If NASA wants lotsa changes made to it (for use on EUS) than Bezos will say "No thank you" and move on. That's avoiding overly intrusive NASA involvement right there.Remember, Blue Origin in no way needs additional business for BE-3 to stay in business, courtesy of the very deep pockets of Bezos.M1-D is an existing engine with thousands (>10,000) of firings and about 500 on orbital launches -- 1 failure, early in these flights.NASA is forcing change.No, NASA is only in a position to force change when the involved contractor needs the NASA dollars. That's why SpaceX agreed to change the M1D turbopump: they need the NASA money. Blue Origin on the other hand does not need the NASA dollars given that its owner (Bezos) has far deeper pockets than NASA.
Not really. By that time Vulcan will have been flying for some time. NASA will have to accept the BE-4 as-is. Just like they have to accept the RD-180 (on Atlas V) as-is. All Blue has to do is to hand over all documentation regarding BE-4 for review. But NASA can basically not demand any alterations to the engine.
Also, it is unlikely that Starliner missions for NASA will ever fly on anything other than Atlas V.
Not really. By that time Vulcan will have been flying for some time. NASA will have to accept the BE-4 as-is. Just like they have to accept the RD-180 (on Atlas V) as-is. All Blue has to do is to hand over all documentation regarding BE-4 for review. But NASA can basically not demand any alterations to the engine.Also, it is unlikely that Starliner missions for NASA will ever fly on anything other than Atlas V.
Quote from: woods170 on 02/21/2018 05:44 pmNot really. By that time Vulcan will have been flying for some time. NASA will have to accept the BE-4 as-is. Just like they have to accept the RD-180 (on Atlas V) as-is. All Blue has to do is to hand over all documentation regarding BE-4 for review. But NASA can basically not demand any alterations to the engine.Also, it is unlikely that Starliner missions for NASA will ever fly on anything other than Atlas V.NASA accepts RD-180 as-is because they have no other choice. Crew-rating Delta isn't viable and they have no leverage over NPO Energomash. Merlin 1D was already flying for some time with a good record before NASA required SpaceX to make changes.
Quote from: envy887 on 02/22/2018 03:08 amQuote from: woods170 on 02/21/2018 05:44 pmNot really. By that time Vulcan will have been flying for some time. NASA will have to accept the BE-4 as-is. Just like they have to accept the RD-180 (on Atlas V) as-is. All Blue has to do is to hand over all documentation regarding BE-4 for review. But NASA can basically not demand any alterations to the engine.Also, it is unlikely that Starliner missions for NASA will ever fly on anything other than Atlas V.NASA accepts RD-180 as-is because they have no other choice. Crew-rating Delta isn't viable and they have no leverage over NPO Energomash. Merlin 1D was already flying for some time with a good record before NASA required SpaceX to make changes. The only reason why NASA was capable to force SpaceX to change the turbopump is because SpaceX needs the money. NASA has leverage over SpaceX. But NASA has no leverage over Blue Origin.What do you think would have happened when SpaceX would have flat-out refused to re-do the M1D turbopump?The answer is: NASA would not have certified F9/Crew Dragon for CCP missions. That would have resulted in at least $1.5 billion of NASA money not flowing into the pockets of SpaceX. And that is money SpaceX needs for its ultimate goal of having Elon Musk retire on Mars.And if you think that NASA not certifying F9/Crew Dragon is unrealistic, than you don't know NASA. It is not for nothing that there are TWO (2) CCP contractors.Also: NASA has leverage over ULA/Boeing as well. ULA/Boeing had to provide ALL the documentation with regards to RD-180 for review. Had ULA failed to hand it over, it would have resulted in Atlas V not becoming certified for launching Starliner. That is why the successful delivery of the required RD-180 documentation from Russia to ULA/Boeing was such an important milestone. Once NASA certifies Atlas V (and RD-180) for crewed CCP launches, based on documentation alone, it clears the path for Vulcan (and BE-4) becoming certified for crewed CCP launches, based on documentation alone as well.So, other than having to hand over some documentation on BE-4, Blue Origin will be in the clear from any intrusive NASA involvement.But I digress.