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SpaceX Looking For Help With "Landing" Video
Maddog Batty (112434) writes "SpaceX recently made the news by managing to soft land at sea the first stage of rocket used to launch its third supply mission to the International Space Station. Telemetry reported that it was able to hover for eight seconds above the sea before running out of fuel and falling horizontal. Unfortunately, due to stormy weather at the time, their support ship wasn't able to get to the "landing" spot at the time and the first stage wasn't recovered and is likely now on the sea bed. Video of the landing was produced and transmitted to an aeroplane but unfortunately it is rather corrupted. SpaceX have attempted to improve it but it isn't much better. They are now looking for help to improve it further."
I appreciate them looking for public help. It's a gesture of trust and openness usually not seen from either goverment or private corporations.
Though I suspect most the the video is beyond salvage.
In this case "fall horizontal" means "fall into a horizontal position". Not "fall horizontally".
my, your, his/her/its, our, your, their
I'm, you're, he's/she's/it's, we're, you're, they're
There's raw data in one of the links above. Some .ts format.
It still is raw. If you follow the link in the summary "looking for help" http://www.spacex.com/news/201... it takes you to their page where they show you the before and after videos via youtube and give you access to the raw footage. Here's the link they provide to the raw footage: http://www.spacex.com/sites/sp...
Did you already inspect the MPEG bitstream they provided to see what data it does and doesn't look like it might contain?
I did. By watching the video. It's busted beyond repair. There isn't a single worthwhile I-frame. No amount of data outside the I-frames can be used to reconstruct anything.
It really doesn't in this case. It's clearly busted beyond repair. The raw stream does not have any damned I-frames that are salvageable, and the Youtube version accurately represents this fact.
But did you reverse the polarity of the tachyon beam?
Faster! Faster! Faster would be better!
Look up the acronym RTFA sometime. You might be surprised what you find.
partially fixed clip has at least one iframe showing that camera was mounted on top of the fuselage looking down, camera was stationary = all iframes had to see same fuselage
this one iframe could be copied over all the broken ones to see if there is any useful data in the rest of the file
Who logs in to gdm? Not I, said the duck.
There's a lot of information missing to be sure, but it's still worth pointing out that SpaceX posted the raw transport stream data that they got from the rocket, so reconstruction can be done on the raw data rather than YouTube.
Errm, they did have a well planned means to evaluate success: telemetry data. Which they have good copies of. The video is just candy.
The other cameras were on the recovery ship, which couldn't reach the recovery area without, you know, sinking. They'd have ended up roughly where the master recording currently is, resting on the ocean floor.
The problem isn't the camera, it's that the data was garbled during transmission. In part because both the source and destination locations were in constant (and, given the storm, quite random) motion. It's hard to hit the side of the barn when you're aiming from mid-air in the center of a tornado.
That they got even this much is remarkable.
Moof!
Absolutely not. There is still significant gravity in space - it falls by inverse-square law, after all. In LEO the force of gravity is practically undiminished. For a "long" structure you'll soon find out that vertical does exist, because that's the way the long axis of that structure will be oriented. Look up "gravity gradient stabilization".
Of course that discribes the axis toward/away from the Earth. I don't know if there is any preferred direction beyond that, but it would surprise me if extended objects don't feel some force related to the direction of their orbits. Basically I'm sure of up/down, and have a feeling that fore/aft can be differentiated from port/starboard. I'd have to agree that North/South/East/West are meaningless - at least for electrically neutral structures.
The living have better things to do than to continue hating the dead.
Stronger signals take bigger transmitters with higher power consumption. They don't normally require such a signal: for launch (and eventual solid-ground landings) they have line of sight with big receivers, and when they actually recover a stage, they'll be able to get recordings. The splashdown was below the horizon from the launch site, and the video signal was picked up from a chase plane. To top it all off, weather was lousy and deteriorating fast.
They'll have a lot more launches and landings, another water-landing test is coming up soon. Getting video on an early test that was given a 60-70% chance of failure and wasn't even an actual solid-ground landing was a lower priority than trying to make it succeed.
... until they post an analog recording of the telemetry. The bitstream *as decoded* is corrupted because of demodulation errors, and you can't reconstruct data that isn't there. If they have an analog recording, then analog filters can be applied to that in an attempt to create a cleaner input signal to the demodulator stage. An analogy: They have taken a picture of a page of text, rather out of focus and dark, and used OCR software on it. All they are giving us is the output of the OCR software. We need to see the original picture so we can apply better filtering/contrast adjustments to it before attempting pattern recognition.
You seem a little harsh on them.
Recovery of the booster would have been nice for investigation, but it was never intended to be flown again and was never the stated goal. The goal for that mission was a controlled descent and touch down on the ocean, which they accomplished. A 'soft-recover' wasn't the term that they were using.
This goal needed to be reached so that Range Safety at the launch pad can determine that SpaceX can reliably put a rocket down within a mile or so of a target. The next launch - in the next week or so - will attempt to land in the ocean much closer to the launch facility.
The technical difficulties of a soft landing are considerable given the hardware that they've got. With the weight of the empty booster, they can't throttle the engines back far enough to hover. So they fall towards the surface and at the right moment fire the engines to reach a computed zero velocity at touchdown. Doing this with gusty 30-40 knot winds on the surface is tough. 'Landing' on a continuously-undulating surface where there is no consistent level is tougher.
And yes, parts of this have been done before. Sure, there's open-source avionics stacks that can do this thing no problemo. But a controlled return of the first stage of a liquid fuel rocket has never been done before, and this kind of work has most certainly never been done for the relatively tiny amount of money that SpaceX has been spending. *That* is the thing that's getting tongues wagging.
You are in a twisty maze of processor lines, all alike.
There is a lot of hype here.
Well, it was Raw until YouTube re-compressed the hell out of it. Seriously, I don't think you have any shot if you start off with this YouTube footage. If they really want help we need the actual raw bitstream. I/Q output from the receiver would be even better. Even better than that would be diversity receivers. Aren't those guys the rocket scientists?
Available for download: This is the location for the original raw ".ts" file. A second link is also given to a repaired raw ".ts" file showing the results of their efforts. If preferred, you can also get the original ".ts" files at the spacex website near the bottom of that webpage.
Yesterday's Weirdness is Tomorrow's Reason Why
There's not a lot of equipment that's flight rated for the kinds of vibration, temperature and pressure swings required by an external rocket, not to mention power source transmitter and antenna(s). Oh, and it can't interfere with the landing telemetry in any way.
moox. for a new generation.
Click the "looking for help" link and scroll to the bottom.
try "computer, enhance ..."
You *do* realize the power output of a rocket engine isn't electrical, right?
In reality, spacecraft have strictly limited power budgets. The booster's electronics are running off battery power from the moment the umbilicals disconnect. It also flew above the bulk of the atmosphere, so you can't exactly rely on air cooling to keep the transmitter from frying itself...and there's plenty of other power-consuming, heat-producing electronics that have rather more important functions. And a more powerful transmitter would be completely unnecessary for the solid-ground landings, which SpaceX hopes to start by the end of the year.