| Author | Message | ||
     Hughlysses |
Let’s hope the third time is a charm for a successful landing. Watch here: | ||
| Hughlysses |
Launch is imminent!(3:10 PM EST) | ||
| Hughlysses |
First attempt aborted right after ignition. SpaceX is evaluating data to determine if they will try again this afternoon and they will let viewers know. Official SpaceX feed: | ||
| Hughlysses |
SpaceX said they plan to try again in about 2 hours (~5:30 PM EST) | ||
| Aesquire |
I really like the "We'll break some to find out where they break and fix it." attitude. Once upon a time.... The Regulus I missile by Vought, was a program that had a lot of problems, but some really smart people. It was about the size of an early jet fighter, and the technology for remote control and guidance was in the early stages. A very risky program. The big decision early on was to just put landing gear on the thing, so they could test guidance systems, etc. and fly the expensive test vehicle back, to reuse it. Sure, the "real thing" was a throw away cruise missile, but Vought had paid attention to earlier programs and knew that when you had test flights that always ended in a crater or the bottom of the sea, that costs went up quick, and if the problem wasn't something you could see on the limited sensor/telemetry channels, you had no idea why your test vehicle went "boom". That approach did lose a bunch of missiles, but being able to bring them back when they went off course or had other failures let them find the problems much faster, especially things like "Vibration made the plug fall out". In contrast, Boeing with it's waverider tests, would fire a very expensive vehicle over the ocean, and when anything went wrong, it vanished into the depths and they had to build a new one, every time. So instead of flying every week, or month, they flew stuff once a year or less, which really made the program expensive and slow. SpaceX might save a few dollars if they did more modeling, and landed fewer rockets 6 inches too low,  but then they wouldn't catch the weird failures that could kill people in a machine that didn't get the bugs worked out. Computer sims are great, but only with stuff you already have LOTS of real world testing on so you can plug in real numbers. Stuff that is edge of the envelope, hypersonic, marginal, New, the computer model can't tell you the New Failure modes. There was a time in the early 1950's where everyone was predicting Mach 5 passenger planes and hover craft. Then they found out, the hard way, that intersecting shock waves would heat things past the melting point of steel, and hovercraft didn't have brakes. | ||
| Hughlysses |
Getting ready to try again... | ||
| Hughlysses |
YES!!!! THEY DID IT!!! Nailed the landing! | ||
| Hughlysses |
And then 2 minutes later it exploded! Holy crap! | ||
| Aesquire |
https://9gag.com/gag/av5OOQZ From the comments... This is why you don't pick up dud fireworks right away. | ||
| Hughlysses |
No kidding. Some of the video posted shows that a least 2, and probably 3 of the 6 landing gear legs did not lock in place when they were deployed shortly before touch down. The legs are “sacrificial” and partially collapse to absorb the shock of landing. It appears the landing speed was a little high as well. With insufficient shock absorption, there was going to be a problem. The whole ship appears to bounce when it touched down, and after the smoke clears it can be seen the ship is sitting on the skirt, not ~3 feet higher as it would be if the landing gear were supporting it. People are hypothesizing this impact cracked a fuel line, The concentration of methane within the relatively sealed area inside the skirt increased until it reached the LEL when a hot engine component lit the mixture off and BOOM! RUD. Still, an amazing accomplishment. SpaceX fans note it took them a lot longer to get this far with the Falcon rocket. SN11 appears to be ready to go and they moved the big blue crane to the pad today, so they’ll probably be ready to launch it on a few days. Cool stuff... | ||
| Hughlysses |
Great compilation video of the flight, landing, and RUD: | ||
| Oldog |
amazing! | ||
| Hughlysses |
Elon confirmed yesterday that the landing speed was higher than desired. Prior to the flip maneuver, they relit all 3 engines to ensure at least 2 were operating satisfactorily, then shut down one engine and did the flip, then shut one of the remaining engines down, leaving one engine for the landing. Elon said they commanded this one engine to increase thrust but the engine did not ramp up, resulting in a hard landing. He said they didn’t know why the engine didn’t respond, so they were investigating that and they plan to land SN11 using 2 engines to give redundancy. |
