tater Posted August 18, 2017 Share Posted August 18, 2017 Static fire tomorrow at VAFB for the launch Thursday. Quote Link to comment Share on other sites More sharing options...
.50calBMG Posted August 19, 2017 Share Posted August 19, 2017 (edited) 11 hours ago, sevenperforce said: I doubt it. The Falcon 1 used a gimballed preburner exhaust nozzle for roll control on its single first-stage engine, but per the Falcon 9 User's Guide, second-stage roll control is provided only by cold-gas thrusters. The Merlin 1D Vacuum vents preburner exhaust into the nozzle extension for extra thrust and specific impulse (this takes advantage of the fact that the static pressure in the nozzle is very low even though the axial dynamic pressure is rather high). But CRS-1 and 2 were on the Falcon 9 1.0, which used the Merlin 1Cs. Correct me if I'm wrong, but I think the 1C vacuum version did have the gimballed exhaust for the preburner. Edited August 19, 2017 by .50calBMg Quote Link to comment Share on other sites More sharing options...
.50calBMG Posted August 19, 2017 Share Posted August 19, 2017 On an unrelated note, I found a few more ideas on how the Raptor engines could be clustered on a 9m BFR booster thanks to reddit https://www.reddit.com/r/SpaceXLounge/comments/6pccdz/comparison_of_several_possible_engine/ Quote Link to comment Share on other sites More sharing options...
sevenperforce Posted August 19, 2017 Share Posted August 19, 2017 1 hour ago, .50calBMg said: But CRS-1 and 2 were on the Falcon 9 1.0, which used the Merlin 1Cs. Correct me if I'm wrong, but I think the 1C vacuum version did have the gimballed exhaust for the preburner. You're right. I dug up the old Falcon 9v1.0 user guide: https://www.spaceflightnow.com/falcon9/001/f9guide.pdf Quote Link to comment Share on other sites More sharing options...
tater Posted August 19, 2017 Share Posted August 19, 2017 Static fire complete. Quote Link to comment Share on other sites More sharing options...
tater Posted August 20, 2017 Share Posted August 20, 2017 Quote Link to comment Share on other sites More sharing options...
CatastrophicFailure Posted August 20, 2017 Share Posted August 20, 2017 1 hour ago, tater said: They better look bad-S. They're contractually obligated to look bad-S. I wanna see bad-S. Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted August 20, 2017 Share Posted August 20, 2017 Spoiler 1 hour ago, tater said: Dragon, Boring, ITS... The plans are much more ambitious. Quote Link to comment Share on other sites More sharing options...
tater Posted August 20, 2017 Share Posted August 20, 2017 Make em look like suits from the Pearl Harbor of SF movies? Quote Link to comment Share on other sites More sharing options...
IncongruousGoat Posted August 20, 2017 Share Posted August 20, 2017 To be honest, I'd rather SpaceX produce a practical suit that's a measurable improvement over current pressure suits than one that just looks cool. Obviously, Musk being Musk, it's going to look cool regardless, but hopefully the rule of cool doesn't supersede practical considerations. Better it look bland than be bland. Quote Link to comment Share on other sites More sharing options...
StupidAndy Posted August 20, 2017 Share Posted August 20, 2017 I read somewhere that he was going for a spacesuit that was "non-stay-puft" looking Quote Link to comment Share on other sites More sharing options...
tater Posted August 20, 2017 Share Posted August 20, 2017 Quote Link to comment Share on other sites More sharing options...
StupidAndy Posted August 20, 2017 Share Posted August 20, 2017 4 days already to the next mission? its getting faster! Quote Link to comment Share on other sites More sharing options...
CatastrophicFailure Posted August 20, 2017 Share Posted August 20, 2017 12 minutes ago, StupidAndy said: 4 days already to the next mission? its getting faster! Nah, this one's in Cali. They don't seem to be trying for their incredible July cadence right now. Quote Link to comment Share on other sites More sharing options...
tater Posted August 20, 2017 Share Posted August 20, 2017 2 weeks after this one is the OTV launch, then 3 weeks until SES-11, and a few days after that Iridium from VAFB. Quote Link to comment Share on other sites More sharing options...
CatastrophicFailure Posted August 20, 2017 Share Posted August 20, 2017 3 minutes ago, tater said: 2 weeks after this one is the OTV launch, then 3 weeks until SES-11, and a few days after that Iridium from VAFB. Nowhere near their best of, what was it? Like 11 days from the same pad? Great video too, you can really see the angle of attack it comes in at. I wonder what sort of glide ratio it has? Quote Link to comment Share on other sites More sharing options...
tater Posted August 20, 2017 Share Posted August 20, 2017 Dunno, but dang cool. I'd love for the official landing videos to have SOUND. That would rock. Quote Link to comment Share on other sites More sharing options...
.50calBMG Posted August 20, 2017 Share Posted August 20, 2017 I think I remember Musk saying at one point that under the right conditions they could get a 1:1 glide ratio on returning stages, just can"t remember where. I think it may have been at the IAC last year, but I could be wrong. Quote Link to comment Share on other sites More sharing options...
sevenperforce Posted August 20, 2017 Share Posted August 20, 2017 The 1:1 glide ratio is with the Block 5 grid fins. That video was hella cool, though. I was amazed to see the transonic shock forming around the tail just before the landing burn ignition. Also surprised by how long the landing burn was. Quote Link to comment Share on other sites More sharing options...
wumpus Posted August 22, 2017 Share Posted August 22, 2017 On 8/20/2017 at 7:31 PM, sevenperforce said: The 1:1 glide ratio is with the Block 5 grid fins. That video was hella cool, though. I was amazed to see the transonic shock forming around the tail just before the landing burn ignition. Also surprised by how long the landing burn was. Are the boosters that use three engines useable? Those burns cut the landing time by a lot (I don't think a single engine can get a TWR>2, so gravity losses add up). Not sure if they need fuel in separate tanks for side engine cutoff or simply use the main tank (obviously they need some reserves to avoid fuel-out, landing with separate fuel reserves would hurt dry mass). Quote Link to comment Share on other sites More sharing options...
sevenperforce Posted August 22, 2017 Share Posted August 22, 2017 24 minutes ago, wumpus said: Are the boosters that use three engines useable? Those burns cut the landing time by a lot (I don't think a single engine can get a TWR>2, so gravity losses add up). Not sure if they need fuel in separate tanks for side engine cutoff or simply use the main tank (obviously they need some reserves to avoid fuel-out, landing with separate fuel reserves would hurt dry mass). Uh, what? All nine engines feed from the same tank. Quote Link to comment Share on other sites More sharing options...
Nefrums Posted August 22, 2017 Share Posted August 22, 2017 20 minutes ago, wumpus said: Are the boosters that use three engines useable? Those burns cut the landing time by a lot (I don't think a single engine can get a TWR>2, so gravity losses add up). Not sure if they need fuel in separate tanks for side engine cutoff or simply use the main tank (obviously they need some reserves to avoid fuel-out, landing with separate fuel reserves would hurt dry mass). A single engine gets a twr of ~4 when dry, (no fuel left). Looking at the videos the first stage appears to be in the transonic region when the landing burn starts. And as the landing burn lasts for about 30s, so it appear to be about twr 2. It would not be a good idea to make the landing burn shorter as the first stage needs to change course. Before the landing burn starts it is on a ballistic trajectory into the sea. So it won't do damage in case of engine faliure. Quote Link to comment Share on other sites More sharing options...
Racescort666 Posted August 22, 2017 Share Posted August 22, 2017 @tater In the continuous landing footage video around 6:15 there's some glowing toward the bottom of the booster, is that entry heating on the engines? It definitely looks like it happens between the entry burn and the landing burn. Also, the vapor cone at 6:43, awesome. Quote Link to comment Share on other sites More sharing options...
Grand Ship Builder Posted August 22, 2017 Share Posted August 22, 2017 (edited) I forgot how to land my rockets, dang it. Edited August 22, 2017 by Grand Ship Builder Quote Link to comment Share on other sites More sharing options...
StrandedonEarth Posted August 23, 2017 Share Posted August 23, 2017 8 hours ago, Racescort666 said: In the continuous landing footage video around 6:15 there's some glowing toward the bottom of the booster, is that entry heating on the engines? I saw that too, looked like something burning there... Quote Link to comment Share on other sites More sharing options...
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