In about 25 minutes the SpaceX Falcon 9 rocket is scheduled to lift off, sending the Dragon capsule full of supplies to the International Space Station. After the first stage separates they hope to land it on a large barge in the Atlantic Ocean and reuse it. There’s a link in the article where you can watch the launch live.
Looks like they aborted at about T-1:20. 
Yeah, I thought I heard them say there was a problem with the second stage.
Edit: They said “actuator drift”- don’t know what that means.
Wow that just sounds so crazy - from crazy unnecessary to crazy cool, planning to landing the rocket on a barge.
It just seems like landing it in the ocean or on land would give a much better chance of not damaging it then a barge that is subject to waves and swells, and perhaps some side to side movement. And they are only giving it a 50% chance of success. I suppose it would be much easier to recover and clean off if they can pull this off but it does seem to up the chance of damage to the stage.
Also I am assuming that the other 50% is just not failure, but in that a chance to abort to a splashdown.
Well when you launch, you want to throw yourself east. Now, anything not going on into orbit is going to follow a ballistic trajectory and land in the Atlantic if you’re launching from Florida. Unfortunately salt water, fuel tanks and complex engines mix about as well as you’d expect. So to minimize the amount of fuel not used to lift a payload you’d want your rockets to simply correct their flight paths and so you need something that floats.
It’s a neat idea and best of luck to them.
They’ve already landed two in the ocean on previous launches. Landing on the barge is the next step in proving the ability to land it with precision, eventually working towards having it land on solid ground for re-use.
For some reason landing on land seems easier then landing on a barge in the sea. However the water option seems like a better abort to splashdown option and perhaps a greater success chance in you include splashdown as a success.
It’s also safer in case things decide to get 'splodey.
Sure, but there doesn’t happen to be an island in the right spot downrange from the launch site for them to land.
When the second stage separates to continue boosting the payload to orbit, the rocket is at an altitude of ~37 miles, ~28 miles downrange and traveling at ~4500 mph. If no maneuvers were made the first stage would hit the water 100+ miles out into the ocean. (all numbers are very approximate).
Their eventual goal is for the first stage, after separation, to fire engines to negate it’s outbound trajectory and arc back towards land where it’s slow to a controlled, pinpoint landing near it’s original launch site.
To do that requires perfecting the various steps involved. They’ve repeatedly flown a test vehicle called grasshopper to practice various controlled maneuvers. Then they tried maneuvers and water ‘landings’ on actual launches. Now they intend to try real pinpoint landings on a barge.
After that they’ll presumably do barge landing closer and closer to land, to gain experience with the control needed to return to the launch site. Eventually when they sufficiently convince themselves, NASA and the FAA that it can be done safely, they can put it all together and start re-using first stages for launch after launch.
They’re going to try again Friday morning. The Dragon capsule will take a few days to reach the ISS when it does launch; something that’s cool to do is watch it chasing the ISS when it passes overhead. You can find out when the ISS is visible in your area here. So for two or three days after Dragon is launched you can see the ISS go by with Dragon trailing behind, getting closer each day.
Space. Space. Oooh, lady, ooh, lady. Gotta go to space. Space orbit, in my space suit. Wanna see me? Buy a telescope. Gonna be in space. Spaaaaaace!
What’s your favorite thing about space? Mine is space.
Looks like the current launch time is 9:47 UTC on Saturday. I had stayed up for the Tuesday attempt; too bad.
The failure was drift in the “TVC” actuator: that’s “thrust vector control”, or basically a hydraulic (actually “fueldraulic”, or using the kerosene fuel instead of standard hydraulic oil) actuator that moves the nozzle around to steer the rocket. I’m not sure exactly what “drift” means but it’s probably something along the lines of it trying to hold a zero position and yet still moving for some reason. Could be instrumentation error or a lot of other things.
Here is the actuator itself, in case anyone’s interested.
I really hope that there is some excellent video taken of the landing attempt. The previous two attempts were amazing but only poorly recorded. Even an Earth-shattering kaboom would be awesome.
Launch went smoothly, and Dragon is in orbit. It’s on a fast-track rendezvous, so it should berth within 24 hours.
First stage landing attempt–not quite as well. Elon’s Twitter feed says this:
Rocket made it to drone spaceport ship, but landed hard. Close, but no cigar this time. Bodes well for the future tho.
Sounds like the grid fins did their job if they got close to the drone ship. Will be interesting to get the details on exactly why it landed hard.
And then:
Ship itself is fine. Some of the support equipment on the deck will need to be replaced…
Even just hitting a target that small at any speed is a hell of an accomplishment. I know some organizations that would pay good money for that kind of targeting accuracy, and who don’t care too much if the unit is reusable…
I’m interested to know how well this landing went. It’s hard to discern from the twitter feeds,
IMHO this will need to be the landing strategy for a Mars mission. We will need to land a rocket on the surface in order to send astronauts back.
I guess the other option is to send a rocket and fuel ahead of time and somehow combine the two.
Maybe I should start a separate Mars landing thread?
I’m glad Musk has a sense of humor about it. His latest:
Didn’t get good landing/impact video. Pitch dark and foggy. Will piece it together from telemetry and … actual pieces.
It’s definitely progress; while previously, the stage soft-landed, tipped over, and sank into the swamp (er, ocean), they now have actual debris. That’s a big improvement!
Earlier tests had a target accuracy of only around 10 km; this stage at least clipped a 100 m target, which again is a huge improvement. And it might be much better than even that, but we need more information.
Even better: mine the fuel on Mars. Or at least part of it (it might be easier to bring the hydrogen).
Aerocapture, aerobraking, and then retropropulsion do sound like the only viable solution to me. The Martian atmosphere eats the first 5, maybe 6 km/s of delta V. But you still need rockets for the rest. Exactly how much depends on what you’re landing, but even with pessimistic estimates the mass ratios aren’t too bad.
Sure. I had been thinking of a “Design a SDMB Mars mission” thread where we see how cheap we can do a mission for using existing equipment or reasonably straightforward extensions of existing stuff (Falcon Heavy, etc.). I’ve written up some notes but it’s nowhere close to complete.
Dammit, I forgot to set my alarm so I didn’t see the launch live. I watched the video here. Night launches are so impressive. And as Dr. Strangelove said, just hitting the target with the first stage is quite an accomplishment. Congrats to Elon Musk and everyone at SpaceX.
Checking the link in post #10, I’ll only get one chance to watch Dragon chasing the ISS through the sky, tomorrow morning.