So, assuming it tipped over but didn't explode how do they safely approach the rocket now? Are they able to tell if the stage has vented and isn't at risk of exploding? Reminds me of how you should never return to a lit firework but on a much larger scale.
This is going to be their longest 2nd stage coast to date correct?
I see the landing failure as a consequence of the barge's variable altitude, rather than attitude. The rocket is trying to reach a very specific altitude above a very specific position while simultaniously bringing it's velocity to 0. The barge, meanwhile, moves up and down. I believe I saw the sea state as 12 feet earlier, so that means at its peak, the barge could very well have been 6 feet above the nominal altitude, which means... crunch.
Quote from: Lar on 01/17/2016 06:20 pmIf the vid shows that the barge WAS pitching badly but the stage came in much closer to upright with less slew, just still hit one leg first, harder, it means this probably IS solvable, just needs control algorithm refinement. I wonder if the landing control algorithm is predictive, that is using a model for how the drone ship movements and/or wind disturbances will evolve the next couple of seconds.
If the vid shows that the barge WAS pitching badly but the stage came in much closer to upright with less slew, just still hit one leg first, harder, it means this probably IS solvable, just needs control algorithm refinement.
Anyone if the F9 1st stage landing legs has any form of shock absorption? If not, then I think they're just asking too much of the landing legs. They will break very easily as they're very stiff and rigid.
I've been thinking for a while that SpaceX needs something closer to an offshore drilling platform than a barge. With respect to timing the Falcon 9's hover-slam, it seems that the landing platform basically needs to be inert, rather than pitching and rolling with the seas.
Quote from: DaveS on 01/17/2016 06:30 pmAnyone if the F9 1st stage landing legs has any form of shock absorption? If not, then I think they're just asking too much of the landing legs. They will break very easily as they're very stiff and rigid.good point. the leg piston is rigid after it is extended. shock absorption on the legs could help. other ideas:2. strengthen stage 1 with a reinforcing ring around stage at piston attach point3. fiant motion platform on barge (practical?)4. Use oil rig or old carrier as platform. (more atable in these sea states?)[b/]
Surely there is a thrust "reserve" to allow for some margin of error in reducing velocity to zero in the final moments, right? If so, I have a hard time believing a gradual altitude change of six feet would be too much for the stage to handle. Would love to hear some thoughts about this.
Quote from: Astromattical on 01/17/2016 06:34 pmSurely there is a thrust "reserve" to allow for some margin of error in reducing velocity to zero in the final moments, right? If so, I have a hard time believing a gradual altitude change of six feet would be too much for the stage to handle. Would love to hear some thoughts about this.I don't think the stage "knows" that there's a change in the altitude of its landing position.
Add Automated spacecraft drone buoys (ASDB). Measure incoming wave height and predict elevation of barge at landing.
Yes, anything is possible with sufficient $$$ investment. But they are trying to do this within a limited budget.
Is a deorbit burn planned? If not that stage will be up there for quite a while...
Quote from: GWH on 01/17/2016 06:34 pmAdd Automated spacecraft drone buoys (ASDB). Measure incoming wave height and predict elevation of barge at landing.Right. But even if you get a good prediction for the drone ship movements, it's nontrivial to exploit this in the landing algorithm in a reliable manner.
Quote from: JBF on 01/17/2016 06:33 pmThis is going to be their longest 2nd stage coast to date correct?Wasn't DSCOVR a longer coast?
