Wow. Crazy news. What a difference a week makes.I will throw in my guess for S2 reuse. Re-entry and descent will be handled by picaX on top, down one, a flap to protect the nozzle, and some grid fins for control. "Landing" will be handled by a chopper catching the chute and returning it to land near the launch site. I think legs, thrusters, tankage, and propellant will add too much dry mass.Payload adaptors will sit on top of the dome heat shield, and will probably have to be jettisoned, but the CommX deployer might be able to be designed to fold back to the side opposite the PicaX to stay out of the re-entry plasma stream.I think a non-reusable version will be available as well and will be such that it can be easily be converted to reusable and vise versa.I think the changes can be light enough where it can work for both heavy and F9, LEO and GTO.Raptor will eventually be used to up the payload capacity, but probably won't be ready for the first reused S2.
The Merlin main engine can not use all of the propellant. There is always an unusable residue left. How about SpaceX develops a small pressure fed kerolox engine for course adjustment and landing, maybe 2 or 3 are needed. They are not afraid of engine development. During the coasting phase they collect remaining propellant in 2 pressure tanks, separating any He bubbles and use that. Fully powered landing without any extra propellant, especially not hypergols.I was taking a nap. During that time I had this idea. Tell me if it is completely off. I just don't believe in helicopter air recovery.
The Merlin main engine can not use all of the propellant. There is always an unusable residue left.
Quote from: guckyfan on 04/08/2017 12:27 pmThe Merlin main engine can not use all of the propellant. There is always an unusable residue left. The unusable residue claimed is startlingly small for F9 first stage reuse.A couple of hundred kilos from memory, or ~1s of thrust time on merlin.It seems unlikely that the second stage has substantially more dead volume.I question if you can get meaningful pressure fed engines, a pump, tank to hold the propellant in the meantime, and ... in a weight at all comparable to the remaining fuel.
Quote from: CyclerPilot on 04/08/2017 01:58 amWow. Crazy news. What a difference a week makes.I will throw in my guess for S2 reuse. Re-entry and descent will be handled by picaX on top, down one, a flap to protect the nozzle, and some grid fins for control. "Landing" will be handled by a chopper catching the chute and returning it to land near the launch site. I think legs, thrusters, tankage, and propellant will add too much dry mass.Payload adaptors will sit on top of the dome heat shield, and will probably have to be jettisoned, but the CommX deployer might be able to be designed to fold back to the side opposite the PicaX to stay out of the re-entry plasma stream.I think a non-reusable version will be available as well and will be such that it can be easily be converted to reusable and vise versa.I think the changes can be light enough where it can work for both heavy and F9, LEO and GTO.Raptor will eventually be used to up the payload capacity, but probably won't be ready for the first reused S2.Not sure this is true. SpaceX proposed to Air Force to build a Raptor prototype for F9/FH second stage... by end of 2018. Despite protestations to the contrary* on this forum, maybe they intend to use the Raptor for exactly that. Stranger things have happened.* Many based on the statement by EM that they won't build a reusable second stage...
Elon Musk saying reusable upper stage too heavy without Raptor or whatever was referring to the 2-stage Falcon 9 and to GTO. Same logic doesn't apply to Falcon Heavy or to LEO, and definitely not both together.
Quote from: Robotbeat on 04/08/2017 03:50 pmElon Musk saying reusable upper stage too heavy without Raptor or whatever was referring to the 2-stage Falcon 9 and to GTO. Same logic doesn't apply to Falcon Heavy or to LEO, and definitely not both together.Robo, I don't think that's right. At Elon's talk at MIT in '14, he said "I don't expect the Falcon line (emphasis mine) to have a reusable upper stage, just because the...with a kerosene based system the specific impulse isn't really high enough to do that." And he says the later system will be fully reusable. But he clarifies what he means by specifying that the 'later' system is Methane based. So he's clearly talking about ITS/Raptor. So by 'Falcon line' he's clearly talking about both F9 and FH.Do you have a source where he indicates or hints that re-usability might be possible with a Merlin base US for the FH?
What makes this so fascinating is Musk saying they may try to bring the FH demo S2 back this summer! No-one expected that. Presumably that rules out anything but the simplest modifications. And definitely not a Raptor. ...
Reusable upper stage work is essentially subscale ITS spaceship testing.
Quote from: Robotbeat on 04/08/2017 11:26 amReusable upper stage work is essentially subscale ITS spaceship testing.Do you mean 'essentially the role a subscale ITS would have', or 'testing for a subscale ITS'? Because I would love to knock this conjecture-darling subscale ITS concept on its head since it seems to be coming out the woodwork without any proof other than that the idea is popular. People bring it up all the time like it's anything more than some concept we dreamed up on Nasaspaceflight without any bearing on any info that has come out of SpaceX. It's a fiction rocket. It's like falcon 5 to me - irrelevant; a stop-gap which doesn't fulfil the endgoal and only has a reason for creation because of worries the endgoal might be too challenging.Reusable stage 2 on F9 -massively reduces- the need for subscale ITS from my perception.That's not how SpaceX approaches problem resolution. They don't half-arse it because they think they need a tech demo, they go big, then iterate.
Robin... Robinson Manuel, with the New York Observer, Could you give us an update on the development of the Interplanetary Transport System, and what's next in terms of - what's the next component to be tested following the carbon fuel tank and the Raptor engine, what's next?E: So, I think we'll provide an update on the design of the Interplanetary Transport System - Interplanetary Transport System also includes the propellant depot on Mars - that's why it's sort of - I actually usually don't like the word 'system', but we can't call it a rocket if it includes a propellant depot. So the Mars planetary transporter or Mars Transporter, or Interplanetary Transporter - We've come up with a number of design refinements, and I think we'll probably be ready to put that on the Website within a month or so.RM: Just one follow-up, The time frame has kind of shifted since Guadalajara, I was wondering if if you guys had any updated time frame of when you think that first mission will be launched - If I'm correct, the first one is uncrewed, correct?E: Yeah the first ones will be uncrewed. I don't want to steal thunder from that announcement. I'm pretty excited about the updated strategy since Guadalajara, it makes a lot more sense, it's - we have to not just get it done technically, but figure out how to get this done without going bankrupt.
I'd be happy to be proven wrong. I think most of us took Elon at his word when he said plans to re-use Falcon S2 were on hold. And the experts believed him because it's very, very hard to pull off. SpaceX typically hint at progress on projects years before flight, so if a reusable S2 is ready to test soon this will have involved uncharacteristic secrecy. Hopefully more will be revealed soon.
Quote from: The Amazing Catstronaut on 04/08/2017 10:35 pmQuote from: Robotbeat on 04/08/2017 11:26 amReusable upper stage work is essentially subscale ITS spaceship testing.Do you mean 'essentially the role a subscale ITS would have', or 'testing for a subscale ITS'? Because I would love to knock this conjecture-darling subscale ITS concept on its head since it seems to be coming out the woodwork without any proof other than that the idea is popular. People bring it up all the time like it's anything more than some concept we dreamed up on Nasaspaceflight without any bearing on any info that has come out of SpaceX. It's a fiction rocket. It's like falcon 5 to me - irrelevant; a stop-gap which doesn't fulfil the endgoal and only has a reason for creation because of worries the endgoal might be too challenging.Reusable stage 2 on F9 -massively reduces- the need for subscale ITS from my perception.That's not how SpaceX approaches problem resolution. They don't half-arse it because they think they need a tech demo, they go big, then iterate.The track record proves otherwise...When proving all the pieces of the booster reuse strategy, they totally used tech demos (e.g., Grasshopper, F9 v1.1, ..., soft landing on the ocean, ...). Going big then iterating would have been to launch the first F9 booster toward a fully kitted out (like they are today) ASDS, then iterate (after repairs). (Kinda like what people think JB will do with NG. He won't.) Dragon 2 had Dragon 1, launch abort using a tech demo Dragon 1, tether testing SuperDraco hovering, and tech demos still in progress... They'll land a few cargo Dragon 2s on land before crewed land landings.When EM discussed the 'updated strategy' making 'a lot more sense' -- at the same presser that he used to reveal the second stage 'Hail Mary' -- it was game-on for speculating what the more sensible strategy involved.QuoteRobin... Robinson Manuel, with the New York Observer, Could you give us an update on the development of the Interplanetary Transport System, and what's next in terms of - what's the next component to be tested following the carbon fuel tank and the Raptor engine, what's next?E: So, I think we'll provide an update on the design of the Interplanetary Transport System - Interplanetary Transport System also includes the propellant depot on Mars - that's why it's sort of - I actually usually don't like the word 'system', but we can't call it a rocket if it includes a propellant depot. So the Mars planetary transporter or Mars Transporter, or Interplanetary Transporter - We've come up with a number of design refinements, and I think we'll probably be ready to put that on the Website within a month or so.RM: Just one follow-up, The time frame has kind of shifted since Guadalajara, I was wondering if if you guys had any updated time frame of when you think that first mission will be launched - If I'm correct, the first one is uncrewed, correct?E: Yeah the first ones will be uncrewed. I don't want to steal thunder from that announcement. I'm pretty excited about the updated strategy since Guadalajara, it makes a lot more sense, it's - we have to not just get it done technically, but figure out how to get this done without going bankrupt. https://www.reddit.com/r/spacex/comments/62i6m1/recap_of_the_elon_musk_and_martin_halliwell_press/dfmw95b/Good news: We'll know more 'within a month or so'Bad News: EM time