SpaceX Lands a rocket on a barge!

[HP-ILnerd]

Congrats to all involved.  Like many of you I've been watching them develop this for closing on 5 years now?  Going from not even being able to get the stage back into the atmosphere without the supersonic wind shredding it, to this.  I'm impressed, to say the least.
4K footage: 


If you want to watch the whole launch to landing (of the first stage):  (scrub to 18:40 if the index doesn't work):
 https://youtu.be/7pUAydjne5M?t=1121

[EEVblog]

The whole things live with that really neat mission timeline bargraph down the bottom.

[EEVblog]

Congrats to all involved.  Like many of you I've been watching them develop this for closing on 5 years now?  Going from not even being able to get the stage back into the atmosphere without the supersonic wind shredding it, to this.  I'm impressed, to say the least.

It's a ridiculously hard thing to do! 

[RobertoLG]

cool stuff! I always wanted to see something like that in person, maybe some day...

[dr.diesel]

Nothing short of absolutely spectacular.   

Gives me the same feeling as a kid watching the Shuttle launch dreaming of a Star Trek society in space.  Now where it Data's equivalent? 

[Wytnucls]

Absolutely mind blowing. A spectacular display of scientific and engineering accomplishments. Beats blowing up ancient artifacts in the Syrian desert.

[Bud]

Yes but why going into that much trouble, what would be a practical use case ?

[Monkeh]

Yes but why going into that much trouble, what would be a practical use case ?

Uh.. reusing a stage which costs multi-millions to build?

[dr.diesel]

Yes but why going into that much trouble, what would be a practical use case ?

Eventually this research will lead to fancy reusable spacecrafts, which are cheaper.  Right now these guys are pioneering new automation, flight controls/logic/code, sensors whatever else it takes to accomplish such a difficult task.

Gotta start somewhere.

[SeanB]

Yes but why going into that much trouble, what would be a practical use case ?

Henry, what use is that thing you are making? it breaks down often, uses a stinky fuel which is hard to get, can hardly go anywhere, needs a specialist to fix it when it breaks. Parts have to be sent out regularly as they wear out so fast, and you need so many tools to fix it.

[TerraHertz]

Excellent!

Even more amazing that it could land and stay upright with the barge pitching around so much in the heavy swell. That must have been near the limit, surely?

[rrinker]

 Simply amazing. It's science fiction come to life - think about how many novels and movies have various spacecraft just landing on planets purely on rocket motor power. Now add in the additional difficulty factor of the non-stable landing platform. Elon Musk, the real life Tony Stark.

[ajb]

Excellent!

Even more amazing that it could land and stay upright with the barge pitching around so much in the heavy swell. That must have been near the limit, surely?

As far as the landing process, apparently the bigger challenge for this one was the high wind.  If you watch the video from the chase plane you can see the waves are running right-to-left, suggesting the wind is blowing in the same direction.  The rocket is tipped towards the right as it approaches, but doesn't seem to have much horizontal velocity, suggesting the attitude is meant to thrust against the wind rather than any residual horizontal momentum from its boostback.  Once it rights itself for touchdown, you can see it starts getting blown to the left, and lands a bit to the left of center on the barge.  I wonder if they're going to have to start compensating (more?) for wind speed in the terminal guidance algorithm; much more and it would have been blown off the barge entirely. 

By the time it's sitting on the barge, the first stage has practically no fuel left, so the bulk of its remaining mass (the engines) is in the bottom couple of meters, while the top is mostly lightweight tanks full of inert gas.  So it's far more stable after touch down than its proportions would suggest.  Even so, apparently one of the first things the recovery crew does is place steel 'shoes' over the rocket's feet and weld them to the deck of the barge as a safety measure--it would really suck to have the rocket stick the landing only to tip over on its way back to port! 

This clip has great (but NSFW) audio:

[Howardlong]

From a buddy of mine on FB:

Developer: "We went into orbit and landed back again on a barge in very choppy seas"
Client: "You didn't make the middle of the target area"

[dannyf]

what would be a practical use case ?

Great question.

A few breakthroughs:

1) re-ignitable and thrustable solid fuel rockets;
2) reusable rockets.

The first is truly revolutionary and quite useful. The 2nd is questionable at this point.

The rocket didn't ace the landing - it is off center.

[sleemanj]

Yes but why going into that much trouble, what would be a practical use case ?

The 1st stage (the bit they landed) construction cost is a massive financial compponent of the entire launch cost, something like 70% i believe.  If the stage can be retrieved, and used again, cost reductions  happen.

For most launches it has no hope of getting back to dry land, it is too far away.and doesn't have sufficient propellant, so a barge is necessary to take the landing point to the rocket.

[dr.diesel]

Client: "You didn't make the middle of the target area"

Although it appears slightly off target, I wonder at what point the software stops correcting and considers it good enough?  After all, it's on the barge, mission accomplished, what point is there in achieving sub Planck length?

[Howardlong]

Client: "You didn't make the middle of the target area"

Although it appears slightly off target, I wonder at what point the software stops correcting and considers it good enough?  After all, it's on the barge, mission accomplished, what point is there in achieving sub Planck length?

I don't know but if I were the "developer" I'd be well chuffed. In a gusty/choppy scenario like that, I'd say all bets are off on a spot-on landing. I don't know what the exact weather was but it looked like something a floatplane wouldn't consider safe, looked like about 20G25 at least.

[RobertoLG]

I only can say to all the folks that participated in that project      impressive!

[mswhin63]

Privatisation can only work if there is a real passion for it. Space X is a good example. Even did better than NASA.

[Brumby]

Simply amazing. It's science fiction come to life - think about how many novels and movies have various spacecraft just landing on planets purely on rocket motor power. Now add in the additional difficulty factor of the non-stable landing platform. Elon Musk, the real life Tony Stark.

[German_EE]

<sigh> My girlfriend saw the video and couldn't see what I was getting so excited about, she then went to YouTube and for the next ten minutes it was 'look at this', 'look at this' as she watched one animal video after another. What SpaceX did is spectacular and amazing, especially when you consider how the barge was behaving in those choppy seas.

[MK14]

Basically, you are hitting a golf ball (then immediately dive in the sea, and go for a swim), and it gets a hole in one, every time. Then bounces out again, and comes back and lands in your pocket (or lands perfectly on top of your flat hat), while you are swimming in VERY heavy seas.

The huge (I presume) cost of each launch, makes real life (full scale) testing, rather limited. So they (presumably), used accurate simulations. Which CAN'T be that accurate, because the atmosphere and weather, are NOT 100% fully understood/predictable yet. So they seem to have done, a really good job.

I wonder if some weather conditions would make accurate landings impracticable. Because the target area looks somewhat small, so there is little room/tolerance to get it wrong, without falling in the sea.

Also Dave should enquire if he can loan/buy some load space on it, and drop the next test meter, from out-space, to make sure that it survives it. Maybe the rocket can make 2 passes. The first, lands the test meter (at FULL terminal velocity), onto solid reinforced concrete. It can then find the landing craft.

[SeanB]

There have been DMM up on the ISS, and quite a few of them have failed ( that pesky radiation thing, or they needed a calibration) so have had a 300km drop test into a soft landing in the South Pacific ocean. So far none have survived, something about 12 kilometers per second being a little on the high side at the beginning of the fall.

[MK14]

There have been DMM up on the ISS, and quite a few of them have failed ( that pesky radiation thing, or they needed a calibration) so have had a 300km drop test into a soft landing in the South Pacific ocean. So far none have survived, something about 12 kilometers per second being a little on the high side at the beginning of the fall.

(Hopefully) Obviously I was joking (about the DMM bit).

But on a serous note. With all the (I would expect), electronics up in the ISS. I would have thought they need, quality/reliable/accurate multimeters, up there. So NASA, should/would/have sorted it out, by now.
It could be that the multimeters, just need better protective cases, so they can work in space. If radiation etc, is a problem.

Or put it another way. Say a vital piece of electronics, became faulty, and they had no idea what was wrong. Electronics experts, on the ground, could guide the astronauts, into using the multimeter, to help diagnose what the fault(s), were. There are presumably experiments going on up there, which also might benefit from multimeters.
Since I have never been on the ISS, I have no idea how they fix electrical problems, up there. Maybe they never get their hands dirty. Although I think, I read/heard they fix stuff outside (the space craft), sometimes.

In practice, I presume the main issue, would be the DMM burning up as it hits the atmosphere. It would be interesting to drop samples, of the main/best DMMs, and see which survives the longest, as they burn up. (Joke)