Quote from: wannamoonbase on 02/15/2023 03:54 pmSwitching to S26 would add months in preflight testing. Maybe they do that, but at this point, just lob something into the atmosphere and clear the OLM for the next set.Yes, and there are several posts that have mentioned S24 can only be flown on B7 because the following ships (S25 onward) are different enough and the following boosters (B9 and onward) are different enough that S24 with B9+ (and B7 with S25+) won't be a viable stack. I believe I remember these posts were well sourced.
Switching to S26 would add months in preflight testing. Maybe they do that, but at this point, just lob something into the atmosphere and clear the OLM for the next set.
So if Ship 26 is for the Tipping Point Demo it has to have at least an additional tank in the cargo area."Large-scale flight demonstration to transfer 10 metric tons of cryogenic propellant, specifically liquid oxygen, between tanks on a Starship vehicle. SpaceX will collaborate with Glenn and Marshall."https://www.nasa.gov/directorates/spacetech/solicitations/tipping_points/2020_selections(Presumably they wouldn't want to transfer liquid oxygen to the methane tanks.)So Cryotesting and structural testing of the new tank structure is a must. Therefore, if Ship 26 is a tanker prototype, it seems likely that it will never see flight and orbit. Some later version could get the fins, flaps, and heatshield for reentry. Why test only 2 of 3 phases if you have such a limited number of launches. We all agree that the Starship factory can crank them out at whatever pace is needed.The only way Ship 26 is getting to fly is if it is deadweight for an early orbital attempt because there is concern that the earlier Starship prototypes would not survive the ascent and risk forcing a flight termination of the booster..
(Presumably they wouldn't want to transfer liquid oxygen to the methane tanks.)
Quote from: baking on 02/15/2023 11:28 pm(Presumably they wouldn't want to transfer liquid oxygen to the methane tanks.)Stupid question here. If they didn't plan on bringing 26 back anyway, and both methane and O2 being cryogenic, would venting one of them to space in a controlled manner clean it up enough to minimize the risk of explosion when pumping the other propellant into the now empty tank?
Only 5 flights/year from Boca Chica, so need to get to FL ASAP (maybe 3rd flight if first 2 are fairly successful?). I think the ramp up is going to be fairly gradual, due to implementing lessons learned about launch support, mainly.
Quote from: wannamoonbase on 02/15/2023 03:54 pmUgh, I can't believe you reference that guy. Of all the very thin YouTuber space guys, he's one of the thinner ones.Agree. I expressly said "His opinion". My post was more of a snarky remark, not meant to inform.Too bad facial expressions can't be seen on posts. I was grinning because I thought his opinion was out there lol.
Ugh, I can't believe you reference that guy. Of all the very thin YouTuber space guys, he's one of the thinner ones.
NASA's WB-57 reconnaissance aircraft's online schedule indicates it is on tap for the S24/B7 mission. I love this platform's capabilities. Should it (optimistically) be in Hawaii to cover the re-entry, or (pessimistically) be offshore from Boca Chica to be in position to cover ascent anomalies? What's your call ... if you were SpaceX ... if you were NASA ... if you were you?
Quote from: mistergoblin on 02/14/2023 07:38 pmIn the update thread, the latest post mentions engine shields being removed, possibly for swapping out engines. If that's the case, this would require another static fire with the new engines, right?If it’s only a two or three, it may not be needed if they’ve already been acceptance fired in Texas.
In the update thread, the latest post mentions engine shields being removed, possibly for swapping out engines. If that's the case, this would require another static fire with the new engines, right?
If doable, I’d have the WB57 peep the stage separation. Get second stage ignition and maybe some booster maneuvering.
Quote from: Robotbeat on 02/14/2023 07:50 pmQuote from: mistergoblin on 02/14/2023 07:38 pmIn the update thread, the latest post mentions engine shields being removed, possibly for swapping out engines. If that's the case, this would require another static fire with the new engines, right?If it’s only a two or three, it may not be needed if they’ve already been acceptance fired in Texas.For fun, 0.99 to the thirty-third power is 71.8 percent. So say (hypothetically) each Raptor 2 has a .99 reliability for startup, the probability of at least one engine not successfully lighting up in a static fire (or launch) is still 28.3 percent. YES, by all means change out the two problem engines and just static fire the pair. But I wouldn't continually repeat the 33-engine static fire until 100% successful. The next time you fire/launch, you still have the 28.3 percent chance of one or more engines opting out. Only SpaceX has an informed estimate of Raptor 2 reliability ... yet if we reduce the hypothetical start reliability per engine to .98, then there's a 48.6% probability of not having all 33 engines starting up for liftoff.Hence the very reason for the massive redundancy.Yet take heart in that Booster 4, with only 29 Raptor 1s, was expected to send Ship 20 to orbit with just 410K-lbs of engine thrust each vs Booster 7's 33 Raptor 2s at 510K-lbs of thrust each (Wikipedia stats). That's 11.9M-lbs of thrust (B4) verses 16.8M-lbs (B7). Or put another way, Booster 7 could lose nine (9) Raptor 2s at liftoff and still have more thrust than Booster 4 would have had with all 29 of its Raptor 1s working.Let's hopefully not delay the orbital launch attempt in the hunt for the perfect static fire.Now if you want to do a full-33 engine attempt at liftoff thrust (Did Elon say 90 percent?) to see how the OLM holds up, well by all means
Quote from: matthewkantar on 02/17/2023 03:18 amIf doable, I’d have the WB57 peep the stage separation. Get second stage ignition and maybe some booster maneuvering.Does it have to be only one choice?I thought there was more than one WB57 in NASA's fleet.
Quote from: matthewkantar on 02/17/2023 03:18 amIf doable, I’d have the WB57 peep the stage separation. Get second stage ignition and maybe some booster maneuvering.I think all of those are doable by onboard cameras, no? Sure not in a 3rd person perspective, but current falcon onboards are pretty great already. Of course, if a stage fails, outside footage is very helpful, but probably not desired to be shown to the general audience.I'm sure they'll have plenty of offboard (is that a term?) Surveillance going on, drones, telescopes, planes, maybe even satellites.that we'll never see (unless elon decides it's funny enough to share)
Should it (optimistically) be in Hawaii to cover the re-entry, or (pessimistically) be offshore from Boca Chica to be in position to cover ascent anomalies? What's your call ... if you were SpaceX ... if you were NASA ... if you were you?