Mad Rocket Scientist Posted July 24, 2017 Share Posted July 24, 2017 5 hours ago, RCgothic said: From what I've heard on Reddit, it was a ridiculously close call and insiders say they're not going to release it for PR reasons. Firstly, look at the scorch trail across the barge. Also the last frame shows spray being kicked up way off the mark. The rocket clearly pulled some crazy last minute manoeuvres. Secondly, insiders describe the booster balancing on one leg and nearly toppling. There is also a reference to CRS6 and the little thruster that couldn't. Apparently this time it could. So the video sounds ridiculously awesome, but don't hold out any hope for a release! It still seems odd, considering that they released the footage of failed landings. Plus, it reflects well on SpaceX that their rocket can land even in terrible situations. Quote Link to comment Share on other sites More sharing options...
sevenperforce Posted July 24, 2017 Share Posted July 24, 2017 Here's what a theoretical 9-meter Raptor-based launch vehicle might look like (4-meter Raptor Vacs and 1.5-meter SL Raptors): Spoiler Quote Link to comment Share on other sites More sharing options...
tater Posted July 24, 2017 Share Posted July 24, 2017 CRS-12 will be the last new Dragon. Future cargo missions using Dragon will all be previously flown. SpaceX is currently building 4 Dragon 2 vehicles. Quote Link to comment Share on other sites More sharing options...
sevenperforce Posted July 24, 2017 Share Posted July 24, 2017 2 minutes ago, tater said: CRS-12 will be the last new Dragon. Future cargo missions using Dragon will all be previously flown. SpaceX is currently building 4 Dragon 2 vehicles. Any word on when Dragon 2 Cargo will start flying? Quote Link to comment Share on other sites More sharing options...
CatastrophicFailure Posted July 24, 2017 Share Posted July 24, 2017 14 minutes ago, tater said: CRS-12 will be the last new Dragon. Future cargo missions using Dragon will all be previously flown. SpaceX is currently building 4 Dragon 2 vehicles. I thought the "old dragon" was going to live on for a while as the cargo ship? D2 was only for crew? Quote Link to comment Share on other sites More sharing options...
tater Posted July 24, 2017 Share Posted July 24, 2017 They have a few, they will reuse them until end of life. Quote Link to comment Share on other sites More sharing options...
sevenperforce Posted July 24, 2017 Share Posted July 24, 2017 28 minutes ago, CatastrophicFailure said: I thought the "old dragon" was going to live on for a while as the cargo ship? D2 was only for crew? Previously-flown Dragon 1 spacecraft will continue to be used for CRS cargo missions as Dragon 2 development and testing continues. Once Dragon 2 comes online, new Dragon 2s will be used for both commercial crew and cargo missions alongside reused Dragon 1s until Dragon 1 end of life. Elon hinted at using cargo missions to test Dragon 2 more aggressively than would be possible with crew. We may yet see propulsive landing, if only to splashdown. If I have some time tomorrow, I'll work up the numbers on a real nine-meter ITS. Quote Link to comment Share on other sites More sharing options...
tater Posted July 24, 2017 Share Posted July 24, 2017 There's an ars technical article on ITSy now, assuming 9m. Quote Link to comment Share on other sites More sharing options...
tater Posted July 25, 2017 Share Posted July 25, 2017 ^Source that I could not post because mobile site here is awful. Quote Link to comment Share on other sites More sharing options...
magnemoe Posted July 25, 2017 Share Posted July 25, 2017 2 hours ago, sevenperforce said: Previously-flown Dragon 1 spacecraft will continue to be used for CRS cargo missions as Dragon 2 development and testing continues. Once Dragon 2 comes online, new Dragon 2s will be used for both commercial crew and cargo missions alongside reused Dragon 1s until Dragon 1 end of life. Elon hinted at using cargo missions to test Dragon 2 more aggressively than would be possible with crew. We may yet see propulsive landing, if only to splashdown. If I have some time tomorrow, I'll work up the numbers on a real nine-meter ITS. Can dragon 2 be used for cargo? as in could you use berther instead of docking? Quote Link to comment Share on other sites More sharing options...
sevenperforce Posted July 25, 2017 Share Posted July 25, 2017 45 minutes ago, magnemoe said: Can dragon 2 be used for cargo? as in could you use berther instead of docking? Absolutely. Quote Link to comment Share on other sites More sharing options...
tater Posted July 25, 2017 Share Posted July 25, 2017 Yeah, this was stated a while ago, that D2 would be crew missions, and would then replace D1 for cargos well. That's why many were sad about propulsive landings, as they could have tested on cargo returns (and it would be cool as heck to see---maybe another use for "bouncy house"---as long as it's made of asbestos ). Quote Link to comment Share on other sites More sharing options...
sevenperforce Posted July 25, 2017 Share Posted July 25, 2017 6 minutes ago, tater said: Yeah, this was stated a while ago, that D2 would be crew missions, and would then replace D1 for cargos well. That's why many were sad about propulsive landings, as they could have tested on cargo returns (and it would be cool as heck to see---maybe another use for "bouncy house"---as long as it's made of asbestos ). I'm still holding out for propulsive splashdowns on cargo returns. No reason they can't at least test it out. Quote Link to comment Share on other sites More sharing options...
tater Posted July 25, 2017 Share Posted July 25, 2017 Yeah, incredibly useful for demonstrating the backup safety use, as well. Chutes fail? Powered splashdown. Quote Link to comment Share on other sites More sharing options...
IncongruousGoat Posted July 25, 2017 Share Posted July 25, 2017 There's something else disappointing in all of this: SuperDraco is now no more than a fancy re-usable LES motor, since SpaceX isn't going to be using it for propulsive landings and it's overkill as a maneuvering engine. Quote Link to comment Share on other sites More sharing options...
captainb Posted July 25, 2017 Share Posted July 25, 2017 Musk stated that they found a "better way" to do Mars landings. Any ideas what that might be? Quote Link to comment Share on other sites More sharing options...
HebaruSan Posted July 25, 2017 Share Posted July 25, 2017 3 minutes ago, captainb said: Musk stated that they found a "better way" to do Mars landings. Any ideas what that might be? Rovers? Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted July 25, 2017 Share Posted July 25, 2017 (edited) 2 hours ago, captainb said: Musk stated that they found a "better way" to do Mars landings. Any ideas what that might be? Spoiler They understood that the space is indeed an endless solid rock with "planet" hollows... ...and bet on HITS - Hyperloop Interplanetary Tunnel System. Spoiler Their secret slogan will be: "Space flight is boring!" Edited July 25, 2017 by kerbiloid Quote Link to comment Share on other sites More sharing options...
Streetwind Posted July 25, 2017 Share Posted July 25, 2017 3 hours ago, captainb said: Musk stated that they found a "better way" to do Mars landings. Any ideas what that might be? Just a straight engine-first retropropulsion descent? They have a lot of practice with that by now. No heatshield required, so engines can be center-mounted instead of side-mounted. Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted July 25, 2017 Share Posted July 25, 2017 (edited) 11 minutes ago, Streetwind said: No heatshield required, so engines can be center-mounted instead of side-mounted. Or they have visited a bookstore.https://www.wired.com/2012/10/origin-of-the-apollo-shaped-manned-mars-lander-1966/ Pay attention to its hull shape and fins. Spoiler Edited July 25, 2017 by kerbiloid Quote Link to comment Share on other sites More sharing options...
Nibb31 Posted July 25, 2017 Share Posted July 25, 2017 6 hours ago, magnemoe said: Can dragon 2 be used for cargo? as in could you use berther instead of docking? Dragon 2 doesn't have a CBM, so it can't be berthed. But nothing prevents you from delivering cargo through a docking port. Only ISPR racks require a CBM and there are no plans to carry any up or down at this stage. Quote Link to comment Share on other sites More sharing options...
sevenperforce Posted July 25, 2017 Share Posted July 25, 2017 The inescapable problem with landing with downward-facing engines, assuming you intend to use those engines again, is regolith damage. Rocks and debris kicked up by the engine plume are almost guaranteed to damage your engine bells, and then you're boned. The LM (and, if I read the diagrams correctly, the Mars Lander shown above) had its ascent engines shielded during descent, so this wasn't a problem. Red Dragon would have had its SuperDracos tucked up above the heat shield, albeit with some cosine losses. But ITS and anything with a similar profile is going to have to land on its engines, and that seems really problematic. Having long landing legs helps, I suppose, but it still seems like unacceptable risk. Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted July 25, 2017 Share Posted July 25, 2017 LK was designed with the only engine, but of course, has never flied irl. Spoiler Quote Link to comment Share on other sites More sharing options...
Elthy Posted July 25, 2017 Share Posted July 25, 2017 28 minutes ago, sevenperforce said: The inescapable problem with landing with downward-facing engines, assuming you intend to use those engines again, is regolith damage. Rocks and debris kicked up by the engine plume are almost guaranteed to damage your engine bells, and then you're boned. The LM (and, if I read the diagrams correctly, the Mars Lander shown above) had its ascent engines shielded during descent, so this wasn't a problem. Red Dragon would have had its SuperDracos tucked up above the heat shield, albeit with some cosine losses. But ITS and anything with a similar profile is going to have to land on its engines, and that seems really problematic. Having long landing legs helps, I suppose, but it still seems like unacceptable risk. Well, this is only a problem for the first ITS, building a clean, flat surface for the next ones seems extremly easy compared to the other challenges. Quote Link to comment Share on other sites More sharing options...
tater Posted July 25, 2017 Share Posted July 25, 2017 Cosine losses are not undesirable in 2 regimes. For entry, they increase the effective area contributing to drag via the larger bow shock, and for landing when a craft cannot throttle deeply enough to hover. Quote Link to comment Share on other sites More sharing options...
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