@TomHOnce you decide to attempt recovering the mod SLS core in some way. That means you don't need the 130 tonnes lift. Figure how much mass can get to LEO with 4 RS-25 with the supplemental center engine plus the EUS. Then assemble your deep space stack with components around that mass figure. Since you can re-fly the mod SLS core several times a year. Maybe more frequently then the STS if there is handful of mod SLS cores in service.
Hint: If you want a reusable launcher, start with a blank sheet of paper.
Quote from: Zed_Noir on 03/03/2017 08:56 am@TomHOnce you decide to attempt recovering the mod SLS core in some way. That means you don't need the 130 tonnes lift. Figure how much mass can get to LEO with 4 RS-25 with the supplemental center engine plus the EUS. Then assemble your deep space stack with components around that mass figure. Since you can re-fly the mod SLS core several times a year. Maybe more frequently then the STS if there is handful of mod SLS cores in service.You mean, like Falcon Heavy, except using massively expensive engines?(The poor mass fraction and high deceleration burn propellant requirement will put this beast somewhere in the FH payload range.)Hint: If you want a reusable launcher, start with a blank sheet of paper.
Quote from: AncientU on 03/03/2017 11:21 amHint: If you want a reusable launcher, start with a blank sheet of paper.That excludes Spacex. They took an expendable launcher and are trying to make it reusable. Blue is designing theirs for reuse from day one.
So why are they allowed to ditch the SRBs in order to get to the mandated 130 tons? When a 8.4m kerolox booster with large high-thrust hydrolox upper stage would have exactly the same amount of STS heritage, but be faster, cheaper, and safer?
Quote from: Jim on 03/03/2017 01:35 pmQuote from: AncientU on 03/03/2017 11:21 amHint: If you want a reusable launcher, start with a blank sheet of paper.That excludes Spacex. They took an expendable launcher and are trying to make it reusable. Blue is designing theirs for reuse from day one.A dozen or more flights with SLS/RS-25s would be a bit pricey, even knowing what they know now courtesy of SpaceX's technology demonstrations. Even then, the usable SLS payload will be so small (or negative) that it will be a dead end.
And it excludes NASA and its industry partners.
Quote from: Dante80 on 01/06/2016 12:43 pmTo be more precise. One engine takes about 5 years to make. The factory has the capacity to start working on two new engines per year. This means that after 5 years (and assuming that each year you add two new engines to production), 2 engines are delivered for integration. And two for every year after that. 5 years to build an engine!?!?!
To be more precise. One engine takes about 5 years to make. The factory has the capacity to start working on two new engines per year. This means that after 5 years (and assuming that each year you add two new engines to production), 2 engines are delivered for integration. And two for every year after that.
And still after everything settles, we could still be in the same place as we were in the 90's. (stuck in LEO)
Quote from: envy887 on 03/02/2017 06:54 pmSo why are they allowed to ditch the SRBs in order to get to the mandated 130 tons? When a 8.4m kerolox booster with large high-thrust hydrolox upper stage would have exactly the same amount of STS heritage, but be faster, cheaper, and safer?Sorry, I don't understand. Do you mean "why are the not allowed to ditch the SRBs...?" I was not aware that any 8.4-m kerolox design without SRBs could loft 130 tonnes.
Quote from: Jim on 03/03/2017 01:35 pmQuote from: AncientU on 03/03/2017 11:21 amHint: If you want a reusable launcher, start with a blank sheet of paper.That excludes Spacex. They took an expendable launcher and are trying to make it reusable. Blue is designing theirs for reuse from day one.Strongly disagree.Better put was as they learned orbital launch, they agile - developed a increasingly recoverable LV and continued the process heading into reuse. And ITS is a reuse from the ground up.Blue Origin learned engines and vehicles for reuse in waterfall. Then they began to apply it to the suborbital business with follow on to orbital business, and recently announced lunar surface cargo business.Also look at vehicle strategy - SX keeps stretching a small vehicle larger (tank stretches, uprated engines, parallel staging,...), while BO increments up the vehicle size/scope more granularly.Also with ITS we're talking about a single vehicle architecture with high reuse/interdependence and a very narrow CONOPS yielding a broad range into a landed/return on other bodies.Long ranged with BO is a very different story. And with Bezos recent comments, it's beginning to sound like he wants to "deliver the pickaxes and shovels for the gold rush", not "convey the miners, pans, and rations".So either of these can decrease NASA's dependence on "doing it all". And neither of these really fit into NASA "hand in glove". Which would help NASA if that somehow were to work.Finally, RS-25 engines, or even a core stage booster that uses RS-25's ... does not seem to aid in this progression.
Quote from: Jim on 03/03/2017 01:35 pmQuote from: AncientU on 03/03/2017 11:21 amHint: If you want a reusable launcher, start with a blank sheet of paper.That excludes Spacex. They took an expendable launcher and are trying to make it reusable. Blue is designing theirs for reuse from day one.Yes, but you were also at the time fond of pointing out that F9 v1.1 (block II) was pretty much a clean sheet redesign of the F9 - (tank diameter was the only similarity) with the clear intent of vertical landing, so the truth and facts are somewhere in between.So they changed an expandable launcher into a reusable one. But they also rebuilt it from almost scratch to do it.
Quote from: Space Ghost 1962 on 03/03/2017 07:18 pmQuote from: Jim on 03/03/2017 01:35 pmQuote from: AncientU on 03/03/2017 11:21 amHint: If you want a reusable launcher, start with a blank sheet of paper.That excludes Spacex. They took an expendable launcher and are trying to make it reusable. Blue is designing theirs for reuse from day one.Strongly disagree.Better put was as they learned orbital launch, they agile - developed a increasingly recoverable LV and continued the process heading into reuse. And ITS is a reuse from the ground up.Blue Origin learned engines and vehicles for reuse in waterfall. Then they began to apply it to the suborbital business with follow on to orbital business, and recently announced lunar surface cargo business.Also look at vehicle strategy - SX keeps stretching a small vehicle larger (tank stretches, uprated engines, parallel staging,...), while BO increments up the vehicle size/scope more granularly.Also with ITS we're talking about a single vehicle architecture with high reuse/interdependence and a very narrow CONOPS yielding a broad range into a landed/return on other bodies.Long ranged with BO is a very different story. And with Bezos recent comments, it's beginning to sound like he wants to "deliver the pickaxes and shovels for the gold rush", not "convey the miners, pans, and rations".So either of these can decrease NASA's dependence on "doing it all". And neither of these really fit into NASA "hand in glove". Which would help NASA if that somehow were to work.Finally, RS-25 engines, or even a core stage booster that uses RS-25's ... does not seem to aid in this progression.There is nothing to disagree with in my statement. I was just posting facts.
Propulsive reentry of the SLS core, if workable, is not likely to be the best way to get reusability of SLS components. As others have stated the entry velocity of the core is ~7.5 km/s which is significantly faster and hotter than Falcon 9's slow 1.5km/s.
The SMART reuse concept may be the best way to get parts of the core back. There is a long history of SDHLV [proposal]s that use discussed recoverable engine pods.
I'm not even sure Pepperidge Farm remembers when this thread was still about RS-25 production.