tater Posted March 31, 2017 Share Posted March 31, 2017 In the presser Musk said that they were upgrading the grid fins in Block 5 so that they'd not burn. I assume that SES-10 at least had the grid fins replaced on the booster. The major stuff wasn't changed though. Link to comment Share on other sites More sharing options...
Steel Posted March 31, 2017 Share Posted March 31, 2017 23 minutes ago, tater said: In the presser Musk said that they were upgrading the grid fins in Block 5 so that they'd not burn. I assume that SES-10 at least had the grid fins replaced on the booster. The major stuff wasn't changed though. SpaceX, the company with the least consistent naming scheme. So far we've had the F9 v1.0, F9 v1.1, F9 Full Thrust and now F9 Block 5. Link to comment Share on other sites More sharing options...
Scotius Posted March 31, 2017 Share Posted March 31, 2017 *cough* Falcon, Dragon and Of Course i Still Love You Link to comment Share on other sites More sharing options...
sevenperforce Posted March 31, 2017 Share Posted March 31, 2017 15 hours ago, HebaruSan said: Circularization burn started. ... and finished. Technically the circularization burn was completed while the booster was landing; the second burn is at the perigee of the geostationary transfer orbit. 15 hours ago, CoreI said: Yeah, I got a little scared there. I don't remember ever seeing that happen there. Although, if that left (from the webcast PoV) grid fin had given way and fallen off, would the rocket have been able to land? This may be the case considering that the Falcon 9 was built from the ground up with redundancy in mind. SpaceX has claimed that one engine can go out and the mission could be fine. But does the same apply for grid fins? The grid fin actually did catch fire...and by catching fire, I mean the aluminum started to burn with the oxygen. At least that's what was implied during the presser. They are switching to titanium for Falcon 9 Block 5. I imagine that in the event of a grid fin loss, they've already programmed the opposite grid fin to fold closed, or for the other two to adjust their angle to maintain nearly the same control authority. It would be dicey, though. 15 hours ago, CSE said: Are they planning to re-reuse this booster, or is it destined to become a museum piece or similar fate? Perhaps it's a conscious decision to push the limits if it's the last flight, gather more data. After they do the inspections (and, potentially, some investigative test-fires), they're presenting it to the Cape as a gift. SES is also getting some pieces for its board room. Link to comment Share on other sites More sharing options...
sevenperforce Posted March 31, 2017 Share Posted March 31, 2017 15 hours ago, KerbalSaver said: At the risk of sounding dramatic, it's possible that historians will mark today as the beginning of a new age in spaceflight. If you have any champagne, now's the time to open it. In the technical webcast, one of the SpaceX employees said "Go for launch, go for age of reflight." Thought that was a fantastic touch. Link to comment Share on other sites More sharing options...
TheEpicSquared Posted March 31, 2017 Share Posted March 31, 2017 With SES-10 successful, I'll now go back to my usual routine: Hyping for the next SpaceX launch! (NROL-76) Link to comment Share on other sites More sharing options...
sevenperforce Posted March 31, 2017 Share Posted March 31, 2017 15 hours ago, mikegarrison said: No, no, I meant THIS turnaround. The SpaceX launch today. Does anyone know how expensive the testing and refurb work was? Obviously the costs will be different between a very large, manned ship and a fairly small unmanned first stage. But it would be interesting to know whether this launch actually cost more than if they had just used a new one. My gut says that the actual, physical refurbishment done to this stage was significantly more than the cost of testing and certifying a new stage, but significantly less than the cost of a new stage. If you include the development costs (all the testing, inspections, and refurbishments done to prior landed stages), then it's certainly more than the cost of a new stage. Link to comment Share on other sites More sharing options...
Benjamin Kerman Posted March 31, 2017 Share Posted March 31, 2017 Relevant XKCD Link to comment Share on other sites More sharing options...
sevenperforce Posted March 31, 2017 Share Posted March 31, 2017 15 hours ago, mikegarrison said: 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. Person-sized. 14 hours 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. 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. Yeah, the reuse of the F9 first stage is closer to the reuse of the SRBs than to the reuse of the orbiter. Though, on that note, the reuse of the F9 first stage is vastly better in every way than the reuse of the SRBs. The SRBs were ditched in the ocean, towed to shore, and completely rebuilt inch-by-inch. Link to comment Share on other sites More sharing options...
StrandedonEarth Posted March 31, 2017 Share Posted March 31, 2017 (edited) 1 hour ago, Steel said: F9 Block 5. F9B5..... Sounds like a Star Wars droid. Not surprising since the Falcon is named after Han Solo's iconic YT-1300 freighter. Elon said so himself. 2 hours ago, kerbiloid said: Was the booster reused entirely? I'm pretty sure they replaced the legs. Those get pretty toasted during landing. I think that's another thing in line for an upgrade to a more durable version. Edited March 31, 2017 by StrandedonEarth Link to comment Share on other sites More sharing options...
Camacha Posted March 31, 2017 Share Posted March 31, 2017 3 hours ago, mikegarrison said: It's good to have options, and the shuttle was a really expensive way to ferry crew to the ISS. On the other hand, the shuttle also delivered most of the ISS to orbit, plus the crew to assemble it and the living space to stay there while they did it, all at the same time. Different missions. I am curious how we will turn out to be doing that in the near and not so near future. Something tells me that launching payload and crew separately might be more efficient. We all know part of the massive cost of the Space Shuttle came from having to man rate everything every time. Also, a system with just crew is simpler and has less things that can go wrong with it. If launches are rare occasions, it makes sense to shoot everything up in one go. If you do it all the time, why not hedge your bets? Meeting up in space is, by now, pretty much a matter of routine. Link to comment Share on other sites More sharing options...
sevenperforce Posted March 31, 2017 Share Posted March 31, 2017 3 hours ago, mikegarrison said: You could buy 4-5 Cessna 152 airplanes for the price of the fuel it takes to fill up the A380 tanks. But what does that mean? Pretty much it means absolutely nothing, because the two airplanes are so different in capability and purpose that making such comparisons is silly. In much the same way, comparing the cost per kg of a ship designed to carry half a dozen people up to LEO for a week+ of time, and also bring a satellite or two, and also de-orbit all those people plus a bunch of cargo, is just not comparable to the cost of delivering a couple satellites. And yeah, Dragon or CST100 or Soyuz is (or is going to be) more efficient than the Shuttle if all you are doing is bringing crew members up to the ISS. But riding your bike to the lake is more efficient than driving a 18-wheel truck to the lake if all you want to do is bring yourself to the lake. It's good to have options, and the shuttle was a really expensive way to ferry crew to the ISS. On the other hand, the shuttle also delivered most of the ISS to orbit, plus the crew to assemble it and the living space to stay there while they did it, all at the same time. Different missions. The payload fairing on the Falcon 9 is wide enough to loft ISS modules. It's also large enough to launch a folded Canadarm. The ISS could have been assembled using repeated Falcon 9 launches (alternating crewed and uncrewed) more rapidly and more cheaply than it was with the Shuttle. And that's if it was being flown expendable. Flying reusable, the cost savings would be astronomical. 2 hours ago, kerbiloid said: 2 hours ago, Steel said: They replaced anything they though could be a potential source of failure. I understand. These potentially are: 9 engines, 2 tanks, legs and avionics. Musk said that the body, tanks, and engines were original. Link to comment Share on other sites More sharing options...
Kryten Posted March 31, 2017 Share Posted March 31, 2017 11 minutes ago, sevenperforce said: The payload fairing on the Falcon 9 is wide enough to loft ISS modules. It's also large enough to launch a folded Canadarm. The ISS could have been assembled using repeated Falcon 9 launches (alternating crewed and uncrewed) more rapidly and more cheaply than it was with the Shuttle. And that's if it was being flown expendable. Flying reusable, the cost savings would be astronomical. None of the US modules were capable of maneuvering in space or attaching autonomously. Link to comment Share on other sites More sharing options...
tater Posted March 31, 2017 Share Posted March 31, 2017 2 minutes ago, Kryten said: None of the US modules were capable of maneuvering in space or attaching autonomously. True. To be fair, though, they were all designed for Shuttle. A station built entirely with SpaceX stuff would have a different design plan, and would clearly require a different stage 2 entirely. Link to comment Share on other sites More sharing options...
Camacha Posted March 31, 2017 Share Posted March 31, 2017 3 minutes ago, Kryten said: None of the US modules were capable of maneuvering in space or attaching autonomously. Does it matter? A folded Canadarm or even a dedicated tug would easily solve that problem. Link to comment Share on other sites More sharing options...
tater Posted March 31, 2017 Share Posted March 31, 2017 2 minutes ago, Camacha said: Does it matter? A folded Canadarm or even a dedicated tug would easily solve that problem. Folded arm attached to what? Current S2 is not capable of docking, the CRS missions use Dragon and trunk, not dragon and S2. The S2 would need to be entirely redesigned to be able to maneuver to get the payload right next to the other components. It's non-trivial, to be sure. Link to comment Share on other sites More sharing options...
Camacha Posted March 31, 2017 Share Posted March 31, 2017 1 minute ago, tater said: Folded arm attached to what? To whatever module you shoot up first. Link to comment Share on other sites More sharing options...
Benjamin Kerman Posted March 31, 2017 Share Posted March 31, 2017 36 minutes ago, sevenperforce said: the cost savings would be astronomical. Astronomical... But yeah, with RCS you could maneuver to do something like apollo did for meeting in LMO. Link to comment Share on other sites More sharing options...
sevenperforce Posted March 31, 2017 Share Posted March 31, 2017 22 minutes ago, tater said: Folded arm attached to what? Current S2 is not capable of docking, the CRS missions use Dragon and trunk, not dragon and S2. The S2 would need to be entirely redesigned to be able to maneuver to get the payload right next to the other components. It's non-trivial, to be sure. That would be part of payload design, not stage redesign. The ISS modules launched by the Shuttle were designed for the Shuttle. An ISS clone launched by the Falcon family would be designed for the Falcon family. But that's not really relevant. There are two ways to do it. The first is for each module to launch with a maneuvering bus, which is something virtually all comsats launched by SpaceX already have. The second way, which is simpler but a little more time-consuming, is for the second stage to place the module in the correct orbit but not decouple it, and simply loiter until Crew Dragon arrives. The second stage would use its cold gas thrusters to hold position while the Crew Dragon docked with the module, and then it would decouple. The Crew Dragon would then be used to maneuver the module to its final destination. Of note: you could do a combination of the two approaches. For example, you could launch the Canadarm module and the first hab module using the Crew Dragon as a bus, then launch the next couple of modules with a robotic maneuvering bus capable of decoupling independently. Then one maneuvering bus could remain attached to the growing station at all times while the other did the task of retrieving modules from unmanned Falcon launches. The maneuvering bus would use SEP, which would save the Crew Dragons from having to expend all their hypergols shuttling modules around. It would be a big job, but it could be done. Definitely more cheaply than the ISS via Shuttle program. Link to comment Share on other sites More sharing options...
HebaruSan Posted March 31, 2017 Share Posted March 31, 2017 2 hours ago, sevenperforce said: Technically the circularization burn was completed while the booster was landing; the second burn is at the perigee of the geostationary transfer orbit. Admittedly I wasn't certain what the second burn was about, but shouldn't it have taken at least 90 minutes to reach the perigee again? Link to comment Share on other sites More sharing options...
sevenperforce Posted March 31, 2017 Share Posted March 31, 2017 Slight change of topic: Musk is yet again making noises about second-stage reuse. Any idea how they'd want to try and manage this, or what modifications S2 would need in order to permit reuse? What kind of payload penalty would be involved? As a related off-shoot from the now-closed ITS-bashing thread: While SpaceX is probably not going to do this any time soon, I'd love to see a cogent design for a fully-reusable combined second stage+Crew Dragon which lands propulsively but doesn't compromise safety. It's a tricky problem. You can't just do a scaled-down ITS because the MVac cannot be used in the atmosphere...in fact, it would be ripped to shreds if it is exposed to the atmosphere at all. And landing on one's tail isn't the best way to land crew, either, for multiple reasons. Link to comment Share on other sites More sharing options...
CatastrophicFailure Posted March 31, 2017 Share Posted March 31, 2017 14 minutes ago, HebaruSan said: Admittedly I wasn't certain what the second burn was about, but shouldn't it have taken at least 90 minutes to reach the perigee again? The second stage adjusts its course so that perigee ends up over the equator in Africa about 20 minutes after SECO. Not totally sure with F9, but I know it's fairly normal for some launchers (like Atlas) to actually reach apogee and start dropping slightly while still burning to orbit. 1 minute ago, sevenperforce said: Slight change of topic: Musk is yet again making noises about second-stage reuse. Any idea how they'd want to try and manage this, or what modifications S2 would need in order to permit reuse? What kind of payload penalty would be involved? Pure speculation here, but I'm guessing the coming upgrades for the F9-B5 might save enough mass to make it possible. That, and IIRC they might put one of the new methane Raptors on it, maybe all together that's enough to make up the difference. 3 minutes ago, sevenperforce said: And landing on one's tail isn't the best way to land crew, either, for multiple reasons. This is exactly how the planned crew Dragon will land... eventually... Link to comment Share on other sites More sharing options...
sevenperforce Posted March 31, 2017 Share Posted March 31, 2017 23 minutes ago, HebaruSan said: Admittedly I wasn't certain what the second burn was about, but shouldn't it have taken at least 90 minutes to reach the perigee again? The burn is at the perigee of the intended geostationary transfer orbit. The Falcon 9 first stage places the second stage in a lofted trajectory, since the MVac has a TWR lower than 1 at staging. So the second stage burns horizontally even while it continues to its initial apogee and starts to drop. The first burn of the second stage is carefully throttled so that the stage reaches a roughly circular parking orbit. The GTO is a Hohmann elliptic transfer between that LEO parking orbit and a geostationary earth orbit; its perigee touches the LEO parking orbit and its apogee touches the GEO orbit. Since the maneuvering bus on the comsat has a TWR far, far lower than 1, it uses the entire duration of the Hohmann transfer to slowly raise its perigee from LEO altitude up to a GEO circularization. Link to comment Share on other sites More sharing options...
Camacha Posted March 31, 2017 Share Posted March 31, 2017 24 minutes ago, sevenperforce said: And landing on one's tail isn't the best way to land crew, either, for multiple reasons. What reasons are those? Link to comment Share on other sites More sharing options...
tater Posted March 31, 2017 Share Posted March 31, 2017 All pre-shuttle US craft landed that way (on their backs, really). As do the Soviet/Russian capsules. Oh, and the Chinese. And BO's capsule will as well. So far, we have 1 example of people landing seated with their posteriors down, everyone else lands on the astronaut's back (reduced spinal compression in the case of a hard landing). Link to comment Share on other sites More sharing options...
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