If you watched live the video of the landing was very patchy. In fact there was just one frame before the rocket landed and it showed the empty barge deck but a huge depression in the surface of the ocean on the other side of the barge and there was an instant and loud in take of breath by the SpaceX crowd.
It really didn't look good, either the rocket had gone into the ocean there or the rocket somehow had hovered over that spot far from its expected landing zone. The video stopped again for what seemed like a long time might have been 30 seconds the next single frame showed the rocket far off center on the barge deck and there was a huge cheer from the SpaceX crew. It must have been a very close call.
I too found that particular set of frames quite interesting. So the last telemetry had stage 1 at 5700 km/sec and 22.3 km in altitude (so about 13 seconds from impact). The landing burn starts and at 24:55 "something" impacts the water really hard next to the barge. The announcer calls "landing burn has started" but you don't see any change in the telemetry (altitude or velocity) so its safe to say the downlink is still not functioning at that point). Then at 25:41 (about a minute later) we see the stage sitting on the drone ship. So once again I'm really surprised they haven't figured done something to stabilize video. Even it it were a 'drone dinghy' 500 yards off to the side holding a steady lock on a satellite or an aerial drone.
The other interesting bit is at 23:42 where we see one of the grid fins in the process of burning off the side of the rocket. Then we lose downlink video from that point on with the stage. It is flying at nearly 4,000 mph at an altitude of 87,000 feet. The SR-71 goes half that fast at that altitude and experiences significant heating on its skin, since drag is proportional to the square of the velocity you're taking 4x the heating.
It has to be a very fine line between burning these things up vs landing them. And clearly the more 'abuse' they will tolerate during re-entry the more fuel you can use toward lift mass. Still, I'm always surprised that they don't use more rocket power to slow down while above 100,000' to avoid the high speed re-entry and then use streamers or drogue chutes rather than RP1 to slow down in the thicker atmosphere.
From what I picked up, their fuel budget for the landing was borderline, as this satellite mission didn't leave them much. This means, they had to go in very fast, and also use a 3 engine landing burn instead of the usual 1 engine. So it was more a test whether they still can land the rocket rather than a proper landing. For that, it performed well.
Yup. And Elon had queued up that exact talking point roughly 3 hours before the launch. However, having watched this company for a while and Elon in particular, he is much more nuanced in what he says. All through SpaceX's life they have leveraged the customers expectations in order to do their own R&D on the customer's nickel. So when they weren't bringing back rockets they charged for the cost of the rocket and then on the now 'waste' rocket invested in using it to test recovery systems of various kinds. Losing the test vehicles is not a problem its cost was covered by the launch. Now that they have some pretty good understanding of recovery, they use 'flight proven' boosters as their test vehicles, bringing them in under different flight regimes using different recovery parameters. I really think it is a brilliant strategy and one that I admire. What I think about is if I was working for them the even more stuff I'd be doing to get even more data from the tests. (like a better video recovery system, which truth be told they very well may have, after all they are under no obligation to show us and their potential competitors what they are trying to improve and what they don't know)
I can't tell by your wording, and I was similarly confused about their video recovery system, so maybe this will be helpful for you.
The only thing SpaceX hasn't invested in is a better downlink. The video is fully recorded and stored on OCISLY, so they will analyze and post later.
The rocket merely interrupts the realtime feed.
Which leads me to believe SpaceX just doesn't care about a robust realtime feed since they can analyze offline -- or they just don't care about one for the public.
Given that the downlink is reasonably stable when OCISLY is just sitting there (with our without a booster sitting on it) I'd love to see them back up on the locally recorded video and then send it via the downlink once the link has restabilized. We're talking about 18 seconds of video here, not hours :-)
I would be interested to hear how SpaceX internally views sharing video with the public. I could imagine a range of feelings from "why waste time showing them" to "an essential part of our marketing and outreach." I personally see it as fascinating stuff that touches on so many interesting questions about rocket design, future space feasibility, and the design limits around cost optimization.
> The video is fully recorded and stored on OCISLY, so they will analyze and post later.
Can you link to any posted-later videos of landings? They pretty consistently either drop frames or cut out entirely on the live stream around the moment of touchdown, so it'd be great to see decent quality footage of some landings.
I mean, it's not like a really robust realtime feed would be much help for them anyway. As far as I know the rocket is completely autonomous, so even if something was going wrong during the landing a higher-quality feed would just give them higher-quality reasons to tear their hair out etc.
I disagree with this. Having diagnosed a number of problems in nominally 'autonomous' robots through the use of video. There are also instances of many issues being diagnosed by video, consider the loss of protection tiles on Columbia which was diagnosed (or at least confirmed) by watching video of the lift-off.
That said, SpaceX has a phenomenal number of video feeds and I really enjoy them. Early in the Falcon 9 project we would see on the web cast a cut to a video shot with no explanation of what it was, but we know now that they were looking a fuel settling and other effects during re-entry.
And yes, given that you can learn a lot from said videos about how it is done, and there is at least one high profile (Blue Origin) and a no doubt a number of low profile efforts on going to duplicate what SpaceX can do, there is some competitive advantage from not sharing all the video they have.
I'm not saying that video wouldn't be helpful, just that realtime video wouldn't be helpful. They surely record the video for later analysis as others have mentioned.
Unless they want to, you know, analyse the landing before they launch another rocket two days later :-) . But of course that doesn't require realtime, just the ability to download via satellite while drone ship is on the move.
Even the lightest wind is also hell on a targeted landing. Our model rocket experiments clearly demonstrate a significant force is applied with even the lightest winds which ends up putting the rocket far off course when choosing landing zones.
We have actually been precalculating trajectories, and have used trial balloons to measure wind speed and direction immediately prior to launches, combined with planned pre-flight path alterations in an effort to land rockets with parachutes more accurately into a targeted area or small designated area.
Not just SpaceX, everything Elon is doing is centered around mars. Yes some of these are a stretch, a big stretch even. Ok a ludicrous stretch. Anyways by company.
SpaceX-pushing rocket tech makes mars a more targetable endevour.
Tesla- better solar panels and better batteries mean you can consume and store more power on be red planet.
Open AI- it's going to be very important to be able to prefab critical systems before any astronauts get there. AI can help there.
Boring Company- Where do you build a home in a place with almost no atmosphere to shield you from radiation? Underground. What's nice and cylindrical and would fit nicely in a tube atop a rocket? Bore segments. Also TBC's bores are being designed with a smaller diameter than your typical bore. Elon says it's so cars can fit in them to revolutionize the LA commute, I see something that can be moduralized and put on top of a heavy lift rocket and used to prefab Martian living quarters.
You have to replace the shock adsorber anyway, the chutes could be as well detachable and replaceable with a ready to go packed one, while the spents are sent back for repacking
From my understanding, the type of parachutes necessary for this, and the associated hardware needed for their safe deployment, are quite heavy and complicated.
I think chutes big enough to save a worthwhile amount of landing fuel would make the vehicle too vulnerable to unpredictable lateral translation due to wind and variable aero braking. That would necessitate using more fuel or bigger and heavier control surfaces to correct for lateral motion. It just doesn't work out.
Also the braking burn just above the atmosphere is already a long high thrust burn. They run three engines for quite awhile at a time when the vehicle has more fuel in it than during landing, which is a single engine burn. Extending that three engine burn significantly would require a lot of extra fuel and as we can see from this landing it isn't needed.
I read that for reusable rocket any chutes increased the start mass and the initial drag to the point making the whole setup infeasible.
Witness Russia tries to design such things. Since about 1985 I read articles about adding small wings and chutes to the first stage of various proposed rockets. Nothing came from that so far.
Me too. And we were talking about the slow obscuring of the video and one thought was that it was stuff coming off the rocket covering the lens but a better explanation is that the lens or other material protecting the camera from the outside was melting. If that is the case we'll need sapphire lens covers for future video streams.
