Robert: If Boeing has had this great concept all along, then why has SMART always baselined MAR, until now?
Quote from: meekGee on 07/19/2022 01:43 pmIt takes the same time to build a rocket whether the engines come from the fabrication line or the refurbishment lineDepends on the proportion of time and cost that is spent on the tanks vs. the engine section. We already know most of the costs are in the engines themselves, and the avionics are also located there, which leaves manufacturing the barrel sections and domes. The rapidly de-matable engine section also means re-mating is not a tortuous affair. QuoteReliability wise, the improvement is partial, since so much of the rocket is not the engines.The expended portion is the tankage. There are few moving parts to fail there.
It takes the same time to build a rocket whether the engines come from the fabrication line or the refurbishment line
Reliability wise, the improvement is partial, since so much of the rocket is not the engines.
Quote from: Comga on 07/19/2022 01:17 amTrevor: We all know about LOFTID. So what?Proof-of-concept test for remaining low TRL item.
Trevor: We all know about LOFTID. So what?
And they can't separate from Vulcan stuff that isn't in a "pod". That would be a major modification to Vulcan's first stage.QuoteDepends on how much of the required hardware the current Vulcan design implements. Could be anywhere from "none at all", to "upstream propellant shutoff valves and feedline slipjoints are already present, pushers are already installed, we've just riveted the engine section in place so it can't come off for the early launches", or anywhere in-between. Dropping engine sections is a technique with good flight heritage (all Atlas vehicles prior to Atlas II-AR/III), and doesn't even need to be done under active thrust for Vulcan.
Depends on how much of the required hardware the current Vulcan design implements. Could be anywhere from "none at all", to "upstream propellant shutoff valves and feedline slipjoints are already present, pushers are already installed, we've just riveted the engine section in place so it can't come off for the early launches", or anywhere in-between. Dropping engine sections is a technique with good flight heritage (all Atlas vehicles prior to Atlas II-AR/III), and doesn't even need to be done under active thrust for Vulcan.
Amusing that the BE-4s they want to recover cost less than the RL-10s they'll always expend.
ULA Refines Plan To Reuse Vulcan Rocket EnginesJuly 20, 2022SECOND IN A SERIES The term “operational reusability” means different things to different space companies. For SpaceX and Blue Origin, rockets that land themselves and quickly return to the launchpad are key to goals to cut costs and develop technologies for human settlements beyond Earth. United...
Excerpts: With the award of 38 Vulcan launches for Amazon’s Project Kuiper, ULA took the BE-4 engine reuse program off the back burner & refined its concept of operations. The initial plan was to have a giant helicopter snare the returning engine pod midair as it descended 1/6
lunder parachute. The helicopter would then fly the engines to a recovery ship. ULA still plans to jettison the spent BE-4 engines (along with some still-to-be-determined amount of the engines’ aluminum attachment ring), deploy an inflatable aeroshell to bleed off speed 2/6
and then deploy parachutes. However, after additional tests and analysis, ULA determined that the aeroshell, known as a hypersonic inflatable aerodynamic decelerator, can effectively double as a splashdown pad, eliminating the need for a helicopter. 3/6
“It turns out the decelerator makes an excellent raft,” says @torybruno. With the simplified recovery plan, ULA figures it needs to refly an engine three times on average to begin saving money. With the helicopter operations, ULA would have needed six. 4/6
Because Vulcan optimized for DoD high-energy missions, propulsive flyback is not a viable option. "We have a big, high-performance booster to get our upper stage almost orbital so that it has as much propellant as possible to do the complicated orbital stuff,” Bruno says. 5/6
As a result, Vulcan 1st stage flies about twice as fast & twice as high as @SpaceX’s Falcon 9 and is much farther downrange than a Falcon 9 when it separates from the upper stage.BE-4 engine splashdown will take place some 1,300 mi. from launch site, depending on trajectory. 6/6
"We have a big, high-performance booster to get our upper stage almost orbital so that it has as much propellant as possible to do the complicated orbital stuff,” Bruno says.
Quote "We have a big, high-performance booster to get our upper stage almost orbital so that it has as much propellant as possible to do the complicated orbital stuff,” Bruno says. Or maybe Vulcan takes its upper stage so far because it has an under-sized upper stage?
Quote from: sdsds on 07/21/2022 06:58 amQuote "We have a big, high-performance booster to get our upper stage almost orbital so that it has as much propellant as possible to do the complicated orbital stuff,” Bruno says. Or maybe Vulcan takes its upper stage so far because it has an under-sized upper stage?Underpowered. See EELV lofted trajectories on many other thread.
Quote from: Jim on 07/21/2022 12:10 pmQuote from: sdsds on 07/21/2022 06:58 amQuote "We have a big, high-performance booster to get our upper stage almost orbital so that it has as much propellant as possible to do the complicated orbital stuff,” Bruno says. Or maybe Vulcan takes its upper stage so far because it has an under-sized upper stage?Underpowered. See EELV lofted trajectories on many other thread. Yup. A consequence of using RL-10, and since RL-10 is expensive, they can’t affordably cluster a lot of them, so it’s more cost optimal to do more work with the first stage.Of course you don’t HAVE to do propulsive fly back. Landing on a ship is an option, if they had the flightrate to support it.
Quote from: dglow on 07/19/2022 06:03 pmAmusing that the BE-4s they want to recover cost less than the RL-10s they'll always expend.That's why the RL10C-X is being implemented - to reduce cost considerably by removing the intricate manual labor in constructing the injector and chamber.
Yup. A consequence of using RL-10, and since RL-10 is expensive, they can’t affordably cluster a lot of them, so it’s more cost optimal to do more work with the first stage.
Of course you don’t HAVE to do propulsive fly back. Landing on a ship is an option, if they had the flightrate to support it.
Quote from: Robotbeat on 07/21/2022 01:08 pmYup. A consequence of using RL-10, and since RL-10 is expensive, they can’t affordably cluster a lot of them, so it’s more cost optimal to do more work with the first stage.No, it is not expense of the engines individually, but developing a new engine
Quote from: Robotbeat on 07/21/2022 01:08 pmOf course you don’t HAVE to do propulsive fly back. Landing on a ship is an option, if they had the flightrate to support it.No, it is not. Still too high of velocity.
There are ways to do it.
I think one of ULA's biggest barriers to reuse is that they do not develop their own engines in house. Developing your engines is difficult, but to make vertical landing to work you need properly sized engines. BE4's, even with deep throttle capabillity seem like they are to powerful to be used by a near empty first stage unencumbered by a full upper stage. The closest sized methane engine that I can think of is Archimedes, which has not been development long, probably too small, and not all that efficient. I think if it weren't for this issue, ULA might have tried to develop a reusable version of Vulcan. And if ULA decided to try and develop a new engine it might take as long as a decade given their lack of experience.
Agreed, but doesn’t help that the unit cost is so high you couldn’t put like 6 of them on there even if you wanted to.
I think one of ULA's biggest barriers to reuse is that they do not develop their own engines in house.
. Developing your engines is difficult, but to make vertical landing to work you need properly sized engines.
I think if it weren't for this issue, ULA might have tried to develop a reusable version of Vulcan.