RCgothic Posted June 1, 2021 Share Posted June 1, 2021 (edited) 21 minutes ago, sevenperforce said: Hmm. This makes me wonder...given basic assumptions about engines and propellant choices (and avoiding an inordinate number of staging events), is there an ideal vehicle configuration for any given orbit? Assume gross liftoff thrust is the limiting factor. Hydrolox would perform better in comparison to kerolox for certain large LEO payloads, but methalox typically beats them both. One of the great things about methalox is its high O/F ratio means its bulk density is not much different from kerolox but its specific energy is much higher. Cost/complexity no object, I'd guess: Kerolox 1st stage with kerolox crossfeeding side boosters. Maximise thrust. Hydrolox 2nd stage to push an enormous mass into LEO. Hydrolox 3rd stage for GTO/TLI. It's not that much DV really. Methalox 3rd stage for beyond. Refuelling, complexity and cost considerations would seem to completely bias the scale towards straight methalox however. Edited June 1, 2021 by RCgothic Quote Link to comment Share on other sites More sharing options...
sevenperforce Posted June 1, 2021 Share Posted June 1, 2021 56 minutes ago, RCgothic said: Cost/complexity no object, I'd guess: Kerolox 1st stage with kerolox crossfeeding side boosters. Maximise thrust. Hydrolox 2nd stage to push an enormous mass into LEO. Hydrolox 3rd stage for GTO/TLI. It's not that much DV really. Methalox 3rd stage for beyond. Refuelling, complexity and cost considerations would seem to completely bias the scale towards straight methalox however. Is that assuming that the limiting factor is gross liftoff thrust? Cost is the limiting factor, of course, but it's difficult to tie that to something specific. The major drivers of cost (all other things being equal) are dry mass and gross liftoff thrust. Quote Link to comment Share on other sites More sharing options...
Singhnaut Posted June 1, 2021 Share Posted June 1, 2021 On 11/2/2020 at 9:49 PM, tater said: Has anyone noticed starhopper sittin right there? Hey, at leastl its newer than grasshopper. Speaking of which, I created a boi called krasshopper with mini landing legs and 4 thud engines. Quote Link to comment Share on other sites More sharing options...
tater Posted June 2, 2021 Share Posted June 2, 2021 Regarding Raptor production, an NSF article from a couple weeks ago says: Quote While Raptors arriving into Boca Chica are in the SN50 and SN60 range, SpaceX’s test site in McGregor is hosting engines in the SN70-80 range, while it is understood that production in Hawthorne is working on engines past SN150 — with a current shipping rate of several Raptors per week. Quote Link to comment Share on other sites More sharing options...
tater Posted June 2, 2021 Share Posted June 2, 2021 Quote Link to comment Share on other sites More sharing options...
tater Posted June 2, 2021 Share Posted June 2, 2021 Quote Link to comment Share on other sites More sharing options...
RCgothic Posted June 2, 2021 Share Posted June 2, 2021 New rocket. NASA mission. No static fire requirement. Money saved. Quote Link to comment Share on other sites More sharing options...
GuessingEveryDay Posted June 2, 2021 Share Posted June 2, 2021 1 hour ago, RCgothic said: New rocket. NASA mission. No static fire requirement. Money saved. Why does this have the vibes of CRS-07? Quote Link to comment Share on other sites More sharing options...
RealKerbal3x Posted June 2, 2021 Share Posted June 2, 2021 2 minutes ago, GuessingEveryDay said: Why does this have the vibes of CRS-07? Did CRS-7 not have a prelaunch static fire? Quote Link to comment Share on other sites More sharing options...
GuessingEveryDay Posted June 2, 2021 Share Posted June 2, 2021 4 minutes ago, RealKerbal3x said: Did CRS-7 not have a prelaunch static fire? Ah, found the article. But the static fire is used to check for problems with the rocket, and I think they should do 2 tests, one in Texas, and another in Florida to ensure no damage during transportation. Quote Link to comment Share on other sites More sharing options...
tater Posted June 2, 2021 Share Posted June 2, 2021 7 minutes ago, GuessingEveryDay said: Ah, found the article. But the static fire is used to check for problems with the rocket, and I think they should do 2 tests, one in Texas, and another in Florida to ensure no damage during transportation. They do a full duration test in TX anyway. Transit damage seems pretty unlikely, and they have done many, many post-transit tests so they know how many have had issues from transit (probably none). In addition, they do a static test anyway, they fire the engines before they release the hold downs. Quote Link to comment Share on other sites More sharing options...
tater Posted June 2, 2021 Share Posted June 2, 2021 Booster Quote Link to comment Share on other sites More sharing options...
RCgothic Posted June 2, 2021 Share Posted June 2, 2021 Suspected for a while. Quote Link to comment Share on other sites More sharing options...
CatastrophicFailure Posted June 3, 2021 Share Posted June 3, 2021 Hmm... really surprised they don’t try to reclaim the tiles, they must have no trouble with producing them in numbers then. Quote Link to comment Share on other sites More sharing options...
StrandedonEarth Posted June 3, 2021 Share Posted June 3, 2021 9 hours ago, kerbiloid said: In beaver suits. Plausible Deniability: Blame Canada! Quote Link to comment Share on other sites More sharing options...
Elro2k Posted June 3, 2021 Share Posted June 3, 2021 Hi everyone, I had a thought the other day and wanted to get y'all to weigh in. As we know, starlink is currently being launched on Falcon 9 in groups of 60. If Starship wasn't currently being developed / was indefinitely delayed, would it be financially viable / practical for SpaceX to launch starlink missions on Falcon Heavy with the new extended fairing? Would this extended fairing make enough of a difference in terms of number of satellites launched? Quote Link to comment Share on other sites More sharing options...
cubinator Posted June 3, 2021 Share Posted June 3, 2021 1 minute ago, Elro2k said: Hi everyone, I had a thought the other day and wanted to get y'all to weigh in. As we know, starlink is currently being launched on Falcon 9 in groups of 60. If Starship wasn't currently being developed / was indefinitely delayed, would it be financially viable / practical for SpaceX to launch starlink missions on Falcon Heavy with the new extended fairing? Would this extended fairing make enough of a difference in terms of number of satellites launched? I think they could get maybe 2x the satellites in that fairing, for 3x the rocket cores. In that case it would be cheaper to launch two Falcon 9s, preferably at the same time and with cameras pointed at each other. Quote Link to comment Share on other sites More sharing options...
JoeSchmuckatelli Posted June 3, 2021 Share Posted June 3, 2021 30 minutes ago, cubinator said: I think they could get maybe 2x the satellites in that fairing, for 3x the rocket cores. In that case it would be cheaper to launch two Falcon 9s, preferably at the same time and with cameras pointed at each other. Watching a simultaneous launch would be massively cool. I'm sure there's been such.... I've never seen it however Quote Link to comment Share on other sites More sharing options...
CatastrophicFailure Posted June 3, 2021 Share Posted June 3, 2021 52 minutes ago, cubinator said: I think they could get maybe 2x the satellites in that fairing, for 3x the rocket cores. In that case it would be cheaper to launch two Falcon 9s, preferably at the same time and with cameras pointed at each other. 20 minutes ago, JoeSchmuckatelli said: Watching a simultaneous launch would be massively cool. I'm sure there's been such.... I've never seen it however Ahem... Spoiler This needs to be reality. Last one to orbit has to babysit Hoppy... Quote Link to comment Share on other sites More sharing options...
SunlitZelkova Posted June 3, 2021 Share Posted June 3, 2021 If they are serious about an orbital flight in July and do not wish to halt work on the orbital tower to fly SN16, I think giving to a museum is a really good idea. It would be pointless to waste money flying it afterwards when the data would not have much value and they would want to focus on more orbital flights. Unflown spacecraft in museums is by no means weird. At the Evergreen Aviation & Space Museum in Oregon, the unflown Mercury capsule for the cancelled MA-10 mission is on display. That museum hasn't been doing well financially and having SN16 on display in the parking lot would help a lot. Quote Link to comment Share on other sites More sharing options...
RCgothic Posted June 3, 2021 Share Posted June 3, 2021 (edited) 3 hours ago, Elro2k said: Hi everyone, I had a thought the other day and wanted to get y'all to weigh in. As we know, starlink is currently being launched on Falcon 9 in groups of 60. If Starship wasn't currently being developed / was indefinitely delayed, would it be financially viable / practical for SpaceX to launch starlink missions on Falcon Heavy with the new extended fairing? Would this extended fairing make enough of a difference in terms of number of satellites launched? Falcon Heavy's fully reusable payload to LEO isn't double F9's. It could lift maybe 22t back calculating from 8t to GTO. That's about 16 extra starlinks (flat packed in pairs). Additional costs are 2x booster refurbishments plus additional refurbishment for a spicier re-entry (and higher risk of loss of) the centre core. Saved cost is one second stage, which is thought to be the majority of the cost of an internal falcon mission. So that might work. I guess we'll know if we start seeing FH Starlink missions. Expending the centre core gets ~90% of fully expendable performance. This could lift over 3x as many starlinks as F9, volume disregarded. So this could lift twice as many most likely. However compared to 2 F9 launches you've got 2 booster refurbs (same) and have expended a first stage and a second stage instead of two second stages, which sounds like a bad trade. 2 hours ago, JoeSchmuckatelli said: Watching a simultaneous launch would be massively cool. I'm sure there's been such.... I've never seen it however That's only ever likely to happen in a full scale nuclear exchange when the missile farms open up. In spaceflight there's no reason to have the risk and complexity of launching two spacecraft at once. Best we'll see is a quick turnaround of the range, Gemini-Agena style. Edited June 3, 2021 by RCgothic Quote Link to comment Share on other sites More sharing options...
Val Posted June 3, 2021 Share Posted June 3, 2021 Split some off-topic discussions off into separate threads. Please keep the discussion to what SpaceX have done, are doing, or have announced plans to do. Quote Link to comment Share on other sites More sharing options...
sevenperforce Posted June 3, 2021 Share Posted June 3, 2021 13 hours ago, CatastrophicFailure said: Hmm... really surprised they don’t try to reclaim the tiles, they must have no trouble with producing them in numbers then. I suspect that the tiles only snap on one way. In other words, once they’re on, the only way for them to come off is to break them. Quote Link to comment Share on other sites More sharing options...
magnemoe Posted June 3, 2021 Share Posted June 3, 2021 5 minutes ago, sevenperforce said: I suspect that the tiles only snap on one way. In other words, once they’re on, the only way for them to come off is to break them. Good chance for that, the tiles might also not be an quality wanted for reentry. They was put on to see if they survived flight and landing. Quote Link to comment Share on other sites More sharing options...
tater Posted June 3, 2021 Share Posted June 3, 2021 16 minutes ago, sevenperforce said: I suspect that the tiles only snap on one way. In other words, once they’re on, the only way for them to come off is to break them. This seems likely. Cast them around a retaining part (metal with undercut), posts are a little wider at top and snap into undercut cast into tile. Quote Link to comment Share on other sites More sharing options...
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