sevenperforce Posted April 6, 2017 Share Posted April 6, 2017 10 minutes ago, tater said: Shuttle landed 99% of the time. 98.52% of the time, if we're being pedantic. But the odds of successfully landing a glider was not exactly the great sticking point in the Shuttle program. Link to comment Share on other sites More sharing options...
tater Posted April 6, 2017 Share Posted April 6, 2017 99% of the times it actually flew into space. I didn't count Challenger, since it was a launch failure. My point was that landing is starting to look routine for SpaceX (awesome), but it was also looking pretty routine for Shuttle, since it succeeded 99.28% of the times it was trying to reenter/land. I hope SpaceX exceeds this, though at one level it doesn't matter, since it's just a thing, there are no crew at risk. Link to comment Share on other sites More sharing options...
mikegarrison Posted April 6, 2017 Share Posted April 6, 2017 Imagine if commercial airplanes only landed safely 99% of the time. There would be about 1000 crashes a week at that rate. Link to comment Share on other sites More sharing options...
tater Posted April 6, 2017 Share Posted April 6, 2017 The key plus for human spaceflight when the craft are capsules with LES is that many of the failures of the past are survivable in a way they are not with aircraft, unless you have an ejection system like the B-58 ejection capsule for all the crew. The sort of heat shield damage that doomed Columbia would not happen with a capsule, since there is little chance of damage when it is covered---that would take something like a SM explosion. Link to comment Share on other sites More sharing options...
sevenperforce Posted April 6, 2017 Share Posted April 6, 2017 1 hour ago, tater said: 99% of the times it actually flew into space. I didn't count Challenger, since it was a launch failure. My point was that landing is starting to look routine for SpaceX (awesome), but it was also looking pretty routine for Shuttle, since it succeeded 99.28% of the times it was trying to reenter/land. Sure. I was pointing out that the act of landing an unpowered rocket plane on a runway was, even for the time, fairly uncontroversial. Pilots had been landing rocket planes as gliders for a while and no one doubted it was possible. In contrast, restarting a kerosene engine while dropping through the sky and landing a 14-story booster with a T/W > 1 wasn't nearly so...routine. Link to comment Share on other sites More sharing options...
PakledHostage Posted April 6, 2017 Share Posted April 6, 2017 12 minutes ago, sevenperforce said: Sure. I was pointing out that the act of landing an unpowered rocket plane on a runway was, even for the time, fairly uncontroversial. Pilots had been landing rocket planes as gliders for a while and no one doubted it was possible. In contrast, restarting a kerosene engine while dropping through the sky and landing a 14-story booster with a T/W > 1 wasn't nearly so...routine. Perhaps, but neither was re-entering something as massive as the shuttle orbiter. As impressive as SpaceX's booster landings are, they are really just an incremental (although fairly substantial) improvement to the SRB recovery system. Bear in mind that something in LEO has to dissipate on the order of 32 megajoules PER KILOGRAM during re-entry while SpaceX's first stage only has to dissipate about 20% of that during its landing. Link to comment Share on other sites More sharing options...
tater Posted April 6, 2017 Share Posted April 6, 2017 29 minutes ago, PakledHostage said: Perhaps, but neither was re-entering something as massive as the shuttle orbiter. As impressive as SpaceX's booster landings are, they are really just an incremental (although fairly substantial) improvement to the SRB recovery system. Bear in mind that something in LEO has to dissipate on the order of 32 megajoules PER KILOGRAM during re-entry while SpaceX's first stage only has to dissipate about 20% of that during its landing. I'd not compare them to dumping the SRBs in the surf at all. An incremental improvement on DCX, yes. SRBs? No. Link to comment Share on other sites More sharing options...
mikegarrison Posted April 6, 2017 Share Posted April 6, 2017 2 hours ago, sevenperforce said: Sure. I was pointing out that the act of landing an unpowered rocket plane on a runway was, even for the time, fairly uncontroversial. Not any that were so big and heavy, however. 1 hour ago, PakledHostage said: Perhaps, but neither was re-entering something as massive as the shuttle orbiter. As impressive as SpaceX's booster landings are, they are really just an incremental (although fairly substantial) improvement to the SRB recovery system. No, that's not true. Making a controlled landing is nothing like a popping a parachute on the SRB. There are a whole host of technologies used in a BO or SX powered landing that simply didn't exist when the shuttle was being designed. First of all, the computing power and speed necessary to control the landing didn't exist in a launchable package then. The precision GPS guidance wasn't available either. It took lots of practice with development programs and also a huge increase in autonomous robotic computing power to even have a chance at doing something so complex. Link to comment Share on other sites More sharing options...
PakledHostage Posted April 6, 2017 Share Posted April 6, 2017 (edited) 1 hour ago, mikegarrison said: No, that's not true. Making a controlled landing is nothing like a popping a parachute on the SRB. I didn't say that it was. Please don't put words in my mouth... I said it was a very substantial but still incremental improvement, in so far as they are recovering the first stage. One that is nowhere near orbital when it separates. How SpaceX do that is obviously more impressive and technically challenging than "popping a parachute". It would be stupid to suggest otherwise. Edited April 6, 2017 by PakledHostage Link to comment Share on other sites More sharing options...
tater Posted April 6, 2017 Share Posted April 6, 2017 Nothing about SRB recovery incremented to F9 booster recovery. What incremented from SRB? Separating from a vehicle heading to orbit. That's the only thing the 2 have in common. SRBs had no control systems, they fell where they fell. Reuse? Not even remotely similar, either. To be an incremental improvement, you'd think that they'd have something in common past being "stages." Link to comment Share on other sites More sharing options...
PakledHostage Posted April 6, 2017 Share Posted April 6, 2017 22 minutes ago, tater said: To be an incremental improvement, you'd think that they'd have something in common past being "stages." Rhetorical hyperbole missed? Link to comment Share on other sites More sharing options...
BadMunky Posted April 6, 2017 Share Posted April 6, 2017 4 hours ago, tater said: I'd not compare them to dumping the SRBs in the surf at all. An incremental improvement on DCX, yes. SRBs? No. the fanboy are strong in this one Link to comment Share on other sites More sharing options...
Elthy Posted April 6, 2017 Share Posted April 6, 2017 (edited) We had this discussion every few weeks over the last years. Can we please have those discussions (both vs. Shuttle and Blue Origin) in another thread and keep this thread about news regarding SpaceX? Edited April 6, 2017 by Elthy Link to comment Share on other sites More sharing options...
magnemoe Posted April 6, 2017 Share Posted April 6, 2017 (edited) Splashdown was spacex initial idea but it would not work, it did not work well for shuttle either as the steel tube is cheap both recovery and the other part of the srb is more expensive, yes it might get a tiny saving but not much. And no powered landings is nothing new, all the moon probes used powered landings. Edited April 7, 2017 by Dman979 Edited to remove references to deleted posts Link to comment Share on other sites More sharing options...
sevenperforce Posted April 6, 2017 Share Posted April 6, 2017 7 minutes ago, magnemoe said: And no powered landings is nothing new, all the moon probes used powered landings. Powered landings with in-air restart of a launch engine following atmospheric re-entry with TWR > 1 is different than the touchdowns of the LM Descent Stage. Very different. That's all anyone was saying. It's like comparing a nuclear submarine to a speedboat simply because they both move through the water and have engines driving screws. Link to comment Share on other sites More sharing options...
PakledHostage Posted April 6, 2017 Share Posted April 6, 2017 (edited) 11 minutes ago, sevenperforce said: That's all anyone was saying. It's like comparing a nuclear submarine to a speedboat simply because they both move through the water and have engines driving screws. And to reiterate, my original statement was intentional hyperbole. Many people (especially in this thread) seem inclined to overstate the significance of SpaceX's achievements while understating the accomplishments of the Shuttle program. Falcon 9's first stage is far, far from orbital when it separates. You just can't compare it's re-entry and landing to that of the space shuttle, full stop. Don't get me wrong, I like watching a SpaceX launch as much as the next guy, but I am not blinded by my fanboyism nor my political ideology. Edited April 6, 2017 by PakledHostage Link to comment Share on other sites More sharing options...
sevenperforce Posted April 6, 2017 Share Posted April 6, 2017 8 minutes ago, PakledHostage said: Many people (especially in this thread) seem inclined to overstate the significance of SpaceX's achievements while understating the accomplishments of the Shuttle program. Falcon 9's first stage is far, far from orbital when it separates. You just can't compare it's re-entry and landing to that of the space shuttle, full stop. Well, at the risk of sounding obtuse... ...why did you? Link to comment Share on other sites More sharing options...
CatastrophicFailure Posted April 6, 2017 Share Posted April 6, 2017 36 minutes ago, Elthy said: We had this discussion every few weeks over the last years. Can we please have those discussions (both vs. Shuttle and Blue Origin) in another thread and keep this thread about news regarding SpaceX? I expect a debate over which end of a boiled egg to open to break out here at any moment. Link to comment Share on other sites More sharing options...
tater Posted April 6, 2017 Share Posted April 6, 2017 (edited) 46 minutes ago, PakledHostage said: And to reiterate, my original statement was intentional hyperbole. Many people (especially in this thread) seem inclined to overstate the significance of SpaceX's achievements while understating the accomplishments of the Shuttle program. Falcon 9's first stage is far, far from orbital when it separates. You just can't compare it's re-entry and landing to that of the space shuttle, full stop. Don't get me wrong, I like watching a SpaceX launch as much as the next guy, but I am not blinded by my fanboyism nor my political ideology. I've overstated nothing at all, I have merely corrected silly comparisons to Shuttle (in both directions, I might add, I pointed out that shuttle (Orbiter) was reused many times, up thread, so F9 was nothing special in that regard). More important in this particular case would probably be actual cost savings. We have only one data point on F9, and according to a statement up in Colorado Springs, the refurb of the SES-10 booster was significantly less than the cost of a new one (and that as the first reflight, it was refurbed much more than any subsequent ones will be). Since the cost of an F9 launch has about ~70% as the booster cost, saving the booster is a meaningful savings. Comparing to Shuttle SRBs is absurd, as they at best broke even with the cost of a new SRB, and I doubt that calculation includes the REAL cost of SRB reuse, which includes a main tank, the Orbiter, Challenger, and her crew, plus the costs of maintaining the program during loss of flight afterwards. Had they used monolithic SRBs they would have eliminated all the failure modes associated with segments. I cannot imagine reuse after a bath in saltwater reduced SRB failure modes any. Regarding total cost savings, I have never consumed the SpaceX or BO koolaid, I have said before in this thread that any such claim will require actual data---which means many SpaceX reuse flights, and some real numbers. I think it's plausible, but aside from loving the landings for sheer cool factor, and the love of "disruption" to the otherwise staid space industry, I am no fanboy (and I haven't seen politics in this thread at all). Edited April 6, 2017 by tater Link to comment Share on other sites More sharing options...
Dman979 Posted April 7, 2017 Share Posted April 7, 2017 Some posts in this thread have been removed or edited. Please refrain from personal attacks. ... and let's keep this about SpaceX, folks. Link to comment Share on other sites More sharing options...
Streetwind Posted April 7, 2017 Share Posted April 7, 2017 5 hours ago, Dman979 said: ... and let's keep this about SpaceX, folks. Yeah, good luck with making that happen! But to start it off, here's a cool montage video about the lifes and travels of the recently reused first stage, shown yesterday at the 33rd Space Symposium: (Here's hoping we'll get it on the official SpaceX account soon.) Link to comment Share on other sites More sharing options...
rkarmark Posted April 7, 2017 Share Posted April 7, 2017 Benzos is all in http://www.theverge.com/2017/4/5/15200102/jeff-bezos-amazon-stock-blue-origin-space-travel-funding Link to comment Share on other sites More sharing options...
CatastrophicFailure Posted April 7, 2017 Share Posted April 7, 2017 Spaceflightnow is saying the next flight is delayed from the 16th, no new date listed. Anyone have any better info? Link to comment Share on other sites More sharing options...
TheEpicSquared Posted April 7, 2017 Share Posted April 7, 2017 2 minutes ago, CatastrophicFailure said: Spaceflightnow is saying the next flight is delayed from the 16th, no new date listed. Anyone have any better info? I wonder if it's caused by SpaceX or the NRO payload. Link to comment Share on other sites More sharing options...
Wjolcz Posted April 7, 2017 Share Posted April 7, 2017 If I'm not mistaken Falcon 9 is the most frequently flown rocket right now, isn't it? We see a launch almost every month. Link to comment Share on other sites More sharing options...
Recommended Posts