Mad Rocket Scientist Posted March 31, 2017 Share Posted March 31, 2017 More from NSF thread: Musk: New design coming for Grid Fin. Will be largest titanium forging in the world. Current Grid Fin is aluminum and gets so hot it lights on fire... which isn't good for reuse. Link to comment Share on other sites More sharing options...
mikegarrison Posted March 31, 2017 Share Posted March 31, 2017 1 minute ago, Mad Rocket Scientist said: More from NSF thread: Musk: New design coming for Grid Fin. Will be largest titanium forging in the world. Current Grid Fin is aluminum and gets so hot it lights on fire... which isn't good for reuse. How big is that grid fin? There are some pretty darn large titanium parts on a lot of airplanes. But perhaps they are castings rather than forgings. Link to comment Share on other sites More sharing options...
StrandedonEarth Posted March 31, 2017 Share Posted March 31, 2017 6 minutes ago, Mad Rocket Scientist said: Chris Gebhartd is posting live updates from a press conference with Elon: https://forum.nasaspaceflight.com/index.php?topic=42544.msg1661101#msg1661101 Notable info: Fairing landed successfully. Musk: Upper stage reuse is next. Musk: Hope to provide update to ITS/BFR soon. Come up with number of design refinements. Update on ITS on website in next month or so. First ITS will be uncrewed. Musk: Goal is to get people on Mars before we're dead and company is dead. LOL That is a fantastic read! Thanks for posting that! Lots of great news and info. Link to comment Share on other sites More sharing options...
Camacha Posted March 31, 2017 Share Posted March 31, 2017 (edited) 5 minutes ago, mikegarrison said: I don't know. I guess I'm just annoyed by the outright ignoring of historical fact. It would be like saying the 707 was the first jet airliner. I don't have to be a fan of the Comet in order to accept that the 707 wasn't actually the first. The 707 was a lot better, in a lot of ways. But I would make myself look pretty foolish if I claimed it was the first ever. Denying the Shuttle is only partly reusable is demonstrably untrue. I do not know why people get so upset over that, but I suspect it has something to do with the Space Shuttle being the end-all Spacecraft in their youth. Even today it is pretty impressive, but mainly for its huge payload capabilities, flexibility, contributions to science and various big space projects and just neat visual appeal. The reusability really was not its strong suit. But apparently that does not jive with what people have been told all their lives. Edited March 31, 2017 by Camacha Link to comment Share on other sites More sharing options...
StrandedonEarth Posted March 31, 2017 Share Posted March 31, 2017 (edited) They're live! Edit: And they're done Edited March 31, 2017 by StrandedonEarth Link to comment Share on other sites More sharing options...
_Augustus_ Posted March 31, 2017 Share Posted March 31, 2017 7 minutes ago, Mad Rocket Scientist said: More from NSF thread: Musk: New design coming for Grid Fin. Will be largest titanium forging in the world. Current Grid Fin is aluminum and gets so hot it lights on fire... which isn't good for reuse. I saw that it was on fire during the stream... wasn't sure if that was good.... 2 minutes ago, Camacha said: Denying the Shuttle is only partly reusable is demonstrably untrue. I do not know why people get so upset over that, but I suspect it has something to do with the Space Shuttle being the end-all Spacecraft in their youth. Even today it is pretty impressive, but mainly for its huge payload capabilities, flexibility, contributions to science and various big space projects and just neat visual appeal. The reusability really was not its strong suit. But apparently that does not jive with what people have been told all their lives. Agreed. Link to comment Share on other sites More sharing options...
DerekL1963 Posted March 31, 2017 Share Posted March 31, 2017 6 minutes ago, Camacha said: That is not vital for a relaunch, which is exactly the point. Since without a second stage, you can't deliver a payload - and the whole point of the vehicle is to deliver a payload, I'd say that yes it *is* a vital part. 3 minutes ago, Camacha said: Denying the Shuttle is only partly reusable is demonstrably untrue. Yet, you seem to find it perfectly acceptable to deny that Falcon 9 is only partly reusable. Link to comment Share on other sites More sharing options...
Camacha Posted March 31, 2017 Share Posted March 31, 2017 (edited) 13 minutes ago, DerekL1963 said: Since without a second stage, you can't deliver a payload - and the whole point of the vehicle is to deliver a payload, I'd say that yes it *is* a vital part. Let us, for the sake of the argument, say we take along a KSP plushy that gets delivered in space, or even a couple of cubesats. Would that make you happy? Quote Yet, you seem to find it perfectly acceptable to deny that Falcon 9 is only partly reusable. The first stage is fully reusable, without having to replace a large and vital part. The first stage is capable of orbit. If you would prefer to wait until the second stage also becomes reusable, that is fine too. Whatever floats your barge. Edited March 31, 2017 by Camacha Link to comment Share on other sites More sharing options...
StrandedonEarth Posted March 31, 2017 Share Posted March 31, 2017 (edited) 15 minutes ago, DerekL1963 said: Since without a second stage, you can't deliver a payload - and the whole point of the vehicle is to deliver a payload, I'd say that yes it *is* a vital part. The point being, the Shuttle Orbiter cannot fire its engines without the external fuel propellant tank, whereas the F9 has fuel propellant tanks as part of that oh-so-reuseable first stage. One plan that was considered was to partly refuel a landed first stage on the barge and fly it back to land. Edited March 31, 2017 by StrandedonEarth Link to comment Share on other sites More sharing options...
cantab Posted March 31, 2017 Share Posted March 31, 2017 Since we're comparing apples and orange tanks, as I see it what SpaceX have done is analogous to recovering just the Shuttle SRBs. The SRBs were essentially the Shuttle's first stage with the SSMEs acting as vernier thrusters. Most of the mass, most of the thrust, but thanks to the rocket equation well under half the speed. And while the Falcon 9 first stage is hardly slow when it re-enters - it scorched the grid fin after all - it's nowhere near the speeds of re-entering the upper stage. The Shuttle by contrast reused both stages and just ditched a drop tank. The ET was important, certainly, but it's pretty much dumb structure. The kind of thing NASA could have hoped to make relatively cheaply. It's not so much different to a military plane flying with a drop tank. On the other hand, the Shuttle showed that reusing the upper stage after it's dealt with the heating load of an orbital re-entry is not easy which made it not cheap. Falcon 9 should work out better for the economics, the first stage is I assume much more expensive than the second whereas with the Shuttle it was the other way round. But re-using the second stage is still something I do not expect to be easy, especially as every kilo added for landing is a kilo less for payload, and it's already about a 100 ton (full) stage pushing a 5 ton payload when the first stage is landing. I won't be surprised to wait another 10 years before SpaceX do it, I won't be surprised if it doesn't happen before Falcon 9 as a whole is superseded, and I won't be surprised if SpaceX try it but then revert to disposable second stages (at least temporarily) on cost grounds. And on a final note, yes Falcon 9 Stage 1 can land and refly. Yes Falcon 9 Stage 1 can theoretically SSTO. But I'm pretty sure it can't do both in one flight! Link to comment Share on other sites More sharing options...
munlander1 Posted March 31, 2017 Share Posted March 31, 2017 So with launching again 24 hours later do they plan to use another rocket? It would make much more since to have several rockets, and have a que of refurbished first stages. Trying to refurbish a rocket in 24 hours seems like a daunting task, with many mistakes made because of the pace required. Link to comment Share on other sites More sharing options...
Camacha Posted March 31, 2017 Share Posted March 31, 2017 7 minutes ago, cantab said: Falcon 9 should work out better for the economics, the first stage is I assume much more expensive than the second [...] From the stream today: a full Falcon 9 costs 62 million dollar. The fuel costs about 200.000 to 300.000 dollar. First stage is about 80% of the costs, which means roughly 50 million dollar. Just now, munlander1 said: So with launching again 24 hours later do they plan to use another rocket? It would make much more since to have several rockets, and have a que of refurbished first stages. Trying to refurbish a rocket in 24 hours seems like a daunting task, with many mistakes made because of the pace required. They explicitly intend to fly an airliner style scheme. Having a fleet of first stages that get worked on in between does not really line up with that goal. They want a quick turnaround. Link to comment Share on other sites More sharing options...
munlander1 Posted March 31, 2017 Share Posted March 31, 2017 2 minutes ago, Camacha said: They want a quick turnaround. Is that doable? Link to comment Share on other sites More sharing options...
Camacha Posted March 31, 2017 Share Posted March 31, 2017 1 minute ago, munlander1 said: Is that doable? If Mr. Musk thinks it is, I am not going to argue. Remember that these rockets are designed from the ground up to do this. Link to comment Share on other sites More sharing options...
StrandedonEarth Posted March 31, 2017 Share Posted March 31, 2017 (edited) 8 minutes ago, munlander1 said: So with launching again 24 hours later do they plan to use another rocket? It would make much more since to have several rockets, and have a que of refurbished first stages. Trying to refurbish a rocket in 24 hours seems like a daunting task, with many mistakes made because of the pace required. Launch and Land and Re-launch! Edited March 31, 2017 by StrandedonEarth Link to comment Share on other sites More sharing options...
Mad Rocket Scientist Posted March 31, 2017 Share Posted March 31, 2017 23 minutes ago, cantab said: Since we're comparing apples and orange tanks, as I see it what SpaceX have done is analogous to recovering just the Shuttle SRBs. [...] Maybe from the standpoint of the SRBs being like a first stage for the shuttle, however from a economics standpoint, SpaceX is recovering the most expensive part of the rocket (75%) and they are doing it in a much more technically challenging way. (propulsively vs. parachutes) Link to comment Share on other sites More sharing options...
HebaruSan Posted March 31, 2017 Share Posted March 31, 2017 3 minutes ago, munlander1 said: So with launching again 24 hours later do they plan to use another rocket? It would make much more since to have several rockets, and have a que of refurbished first stages. Trying to refurbish a rocket in 24 hours seems like a daunting task, with many mistakes made because of the pace required. He specifically said "reflight," which would not apply to separate rockets. But I don't think that tweet means that they're going to schedule the next two launches back to back and cross their fingers with the system as-is. I think it was as much an internal SpaceX memo as it was PR. One of the major goals of the company has been met, a goal that motivated decisions and prioritization and planning for years. So now a new goal needs to be put in its place as a big-picture vision thing, something more near-term than Mars. My guess is that SpaceX employees are even now volunteering for and being selected for a 24-Hour Turnaround Task Force to analyze where the slow pieces are and what it would take to eliminate them. Link to comment Share on other sites More sharing options...
tater Posted March 31, 2017 Share Posted March 31, 2017 The presser was pretty... wow. Fairing recovery. Roomba (xoomba/whatever) to secure in high seas to be used soon. New grid fins that don't burn. From NSF thread as typed by Chris Gebhardt: Quote Question from France: How many times can stages be reused?Musk: Design intent is that rocket can be reflown with ZERO hybrid changes 10 times. Then with moderate refurb, 100 times. We can make it 1,000, but there's no point in that. ITS will be 1,000 reflights. Of course who knows how those numbers work when they actually fly a bunch of times. They have 1 data point on re-fly right now. Link to comment Share on other sites More sharing options...
tater Posted March 31, 2017 Share Posted March 31, 2017 (edited) 4 hours ago, Steel said: At the risk of sounding pessimistic (and also to play devil's advocate), I think historians will more likely mark today as the day SpaceX finally made good on promises it has been making for the best part of a decade now NASA and many "old space" companies talked about reusable rockets, indeed even reusable SSTO rockets 50 years or more ago. 10-15 years seems a bargain. The value of it remains to be seen . Edited March 31, 2017 by tater Link to comment Share on other sites More sharing options...
tater Posted March 31, 2017 Share Posted March 31, 2017 Link to comment Share on other sites More sharing options...
DerekL1963 Posted March 31, 2017 Share Posted March 31, 2017 4 hours ago, StrandedonEarth said: The point being, the Shuttle Orbiter cannot fire its engines without the external fuel propellant tank, whereas the F9 has fuel propellant tanks as part of that oh-so-reuseable first stage. The only relevant question is a bottom line, apples-to-apples comparison - can the vehicle perform it's designed mission? A complete Shuttle stack consists of an Orbiter, an ET, and a pair of SRB's. The Shuttle throws aways the ET, without which it cannot perform it's mission. A complete F9 stack consists of a first stage and a second stage. The F9 throws away it's second stage, without which it cannot perform it's mission. The F9, when treated as a stack (exactly as you treat the Shuttle), is exactly the same as the Shuttle - it throws away parts without which it cannot complete it's designed mission. Whether or not it can fire it's engines is irrelevant. Whether or not it can SSTO (in which case it's neither recoverable nor capable of performing the same mission as the F9) is irrelevant. Link to comment Share on other sites More sharing options...
sojourner Posted March 31, 2017 Share Posted March 31, 2017 Hey, did anyone see the reports of someone beating a dead horse? Link to comment Share on other sites More sharing options...
CatastrophicFailure Posted March 31, 2017 Share Posted March 31, 2017 8 minutes ago, sojourner said: Hey, did anyone see the reports of someone beating a dead horse? Until it is rather soft and runny. Link to comment Share on other sites More sharing options...
Streetwind Posted March 31, 2017 Share Posted March 31, 2017 Oh, I dunno... just the whole notion of "here, you can use this canister of high explosives as a handrail" Link to comment Share on other sites More sharing options...
mikegarrison Posted March 31, 2017 Share Posted March 31, 2017 1 minute ago, Streetwind said: Oh, I dunno... just the whole notion of "here, you can use this canister of high explosives as a handrail" The whole dang rocket (any rocket) is an explosion just waiting to happen. Link to comment Share on other sites More sharing options...
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