Condolences to Elon Musk, we have all been there

[Rocket Farmer]

Don't feel bad your rocket fell over. Just the other day I had Jeb standing on a rock giving his now inverted Duna lander a dirty look. It happens to all of us.

Like the rest of us it's back to the drawing board. Maybe try parachutes next time or more boosters.

[I_Killed_Jeb]

but elon musk doesn't have access to quicksave...

[timsfitz]

It will work next time I bet.

[r4pt0r]

Like they were close.

Really REALLY close.

[Papa_Joe]

Like they were close.

Really REALLY close.

Looks to me like the thrust vectoring reaction time was a bit slow... need to tweak his mech jeb module a bit more...

[Whackjob]

I'd say it's cause for celebration. I mean, LOOKIT THAT FREAGGINTHING! So, so, so, so close.

#EDIT: I wondered why it was veering so much. So I found out. Turns out the engine doesn't have throttle of any kind. So it has to expend more energy to the lateral directions to cut thrust downward. It's actually very intentional. Today I learned!

SCIENCE!

[Deddly]

It was all worth it just for that explosion

[Guest]

I'd say it's cause for celebration. I mean, LOOKIT THAT FREAGGINTHING! So, so, so, so close.

#EDIT: I wondered why it was veering so much. So I found out. Turns out the engine doesn't have throttle of any kind. So it has to expend more energy to the lateral directions to cut thrust downward. It's actually very intentional. Today I learned!

SCIENCE!

A lot of real-life motors have little to no ability to change thrust. :-)

[federicoaa]

he should put some girders on the sides so it does not explode if it falls, the kerbal way

[roosterr]

Notice how breezy it is, as a seasoned sailor I can tell you, by the looks of those white caps it was blowing a bit above 15 knots. Then notice when it looked like it had touched down, the RCS was going hard against the wind direction. As were the vectored thrust before it touched down. If there had been no wind, this one may have landed. MORE RCS please.!

[Hotblack Desiato]

I'd say it's cause for celebration. I mean, LOOKIT THAT FREAGGINTHING! So, so, so, so close.

#EDIT: I wondered why it was veering so much. So I found out. Turns out the engine doesn't have throttle of any kind. So it has to expend more energy to the lateral directions to cut thrust downward. It's actually very intentional. Today I learned!

SCIENCE!

actually, the spaceX merlin 1D is very good at throttling down, for a first stage engine. and it becomes even better, when they start using the engine at full power (currently, that thing runs at 85%, even in ascend). (EDIT): the current throttle capability ranges from 100% to 70%, and even 60% for the vacuum version.

but it can't be throttled down enough in order to get a TWR of roughly 1. in other words, it can't hover. even if they switch off 8 of the engines and let just the inner engine work.

so they need to do a suicide burn, and that was their second real attempt of doing it.

Edited April 16, 2015 by Hotblack Desiato

[jarmund]

I just have to state the obvious: Should've used proper reaction wheels. And of course, moar boosters and struts and all that.

(yes, yes, I know, the KSP reaction wheels are severly overpowered)

On a serious notes, I've been involved in less complicated offshore operations with less wind and swells than that and faced plenty of problems, so I can't believe how close the got despite the weather conditions.

[cicatrix]

This concept of stage recovery is very interesting but I've always had doubts about it. The whole vertical stage is highly unstable even if it just rests on the surface. When you try to land it - well, a slightest breeze can ruin things (as it has just happened). I'm not trying to pretend I'm more clever than the whole Falcon 9 project team, but why didn't they think of something that would help - harpoons firing close to the surface, drag chutes, etc? Surely, RCS should not be the only option.

[Yakuzi]

That looked great! Way better than the previous attempt and considering it had a estimated success rate of less than 50% this isn't bad at all:

Edited April 16, 2015 by Yakuzi

[Streetwind]

I'd say it's cause for celebration. I mean, LOOKIT THAT FREAGGINTHING! So, so, so, so close.

#EDIT: I wondered why it was veering so much. So I found out. Turns out the engine doesn't have throttle of any kind. So it has to expend more energy to the lateral directions to cut thrust downward. It's actually very intentional. Today I learned!

SCIENCE!

I would wager that's not why it was veering so much... this explanation seems more likely:

"Looks like the issue was stiction in the biprop throttle valve, resulting in control system phase lag. Should be easy to fix."

- Elon Musk, in a tweet conversation with John Carmack that he since deleted

In other words, it is possible that the rocket unintentionally oversteered because the execution of the computer's steering commands was lagging a little.

It's also possible that the tweet was deleted because the statement turned out to be wrong, but if you look at the video, the thrust vectoring motion really is somewhat exaggerated and stops too late.

[Yuuray]

This concept of stage recovery is very interesting but I've always had doubts about it. The whole vertical stage is highly unstable even if it just rests on the surface. When you try to land it - well, a slightest breeze can ruin things (as it has just happened). I'm not trying to pretend I'm more clever than the whole Falcon 9 project team, but why didn't they think of something that would help - harpoons firing close to the surface, drag chutes, etc? Surely, RCS should not be the only option.

Well, the stage is mostly empty at this point, and most if the weight is at the bottom, so it's balance is not that big of a problem, I think. Once they move to landing on land it will matter even less.

[Hotblack Desiato]

I would wager that's not why it was veering so much... this explanation seems more likely:

"Looks like the issue was stiction in the biprop throttle valve, resulting in control system phase lag. Should be easy to fix."

- Elon Musk, in a tweet conversation with John Carmack that he since deleted

In other words, it is possible that the rocket unintentionally oversteered because the execution of the computer's steering commands was lagging a little.

It's also possible that the tweet was deleted because the statement turned out to be wrong, but if you look at the video, the thrust vectoring motion really is somewhat exaggerated and stops too late.

that was a problem in ksp too, back when the rcs-thrusters were fireing permanently to compensate their own steering errors... but I believe, that was fixed back in 0.21 or 0.22.

there was a similar problem with mechjeb, it happily drained a 2.5m monoprop-tank while docking.

[waterlubber]

Just because it fell over doesn't mean they lost the components. It can be refurbished.

Anyway, I wonder if with VASIMRs we could do a Falcon Heavy Mun Moon mission!

Edit: 250th post! Woo!

[dryer_lint]

Just because it fell over doesn't mean they lost the components. It can be refurbished.

That's what I was thinking. Then I saw it explode.

I guess real-life water is deadly as well?

[monophonic]

Like they were close.

Really REALLY close.

At 0:14, just before the stage falls into the smoke. Does anyone else think it looks like the RCS at the top of the stage suddenly stops firing to stand up the stage and instead fires, maybe, mostly away from the camera?

[Green Baron]

Notice how breezy it is, as a seasoned sailor I can tell you, by the looks of those white caps it was blowing a bit above 15 knots. Then notice when it looked like it had touched down, the RCS was going hard against the wind direction. As were the vectored thrust before it touched down. If there had been no wind, this one may have landed. MORE RCS please.!

That's it. I find it absolutely amazing how fast the rocket reacts to stabilize and touch down. It might have been blown by the wind (5 bft from the waves) after touchdown and during final approach; windspeed and direction change drastically in the layer above the ground due to friction with the sirface. But i'm shure they know what dynamic forces (wind, movement of the barge from the waves, still some impulse from the engines or whatever) applied in the situation.

If the barge could move steadily downwind and along the waves that'll could make things easier during and after touchdown, but probably more complicated for the final approach, but they know all that. I'm just ... totally ... mindblown ....

... but , well amazing performance nevertheless !

If only i could do that in KSP ..

K

[Starwhip]

They're getting really close. Why are they landing on a barge, though? Why not the middle of nowhere, on solid ground, where it would be easier to land? I suppose the cleanup after a failed landing, but still...

[Drethon]

actually, the spaceX merlin 1D is very good at throttling down, for a first stage engine. and it becomes even better, when they start using the engine at full power (currently, that thing runs at 85%, even in ascend). (EDIT): the current throttle capability ranges from 100% to 70%, and even 60% for the vacuum version.

but it can't be throttled down enough in order to get a TWR of roughly 1. in other words, it can't hover. even if they switch off 8 of the engines and let just the inner engine work.

so they need to do a suicide burn, and that was their second real attempt of doing it.

Makes me think they did the suicide burn too early and scrubbed off too much speed. But then that is better than doing the suicide burn too late. Holes in the recovery barge an all...

[Streetwind]

They're getting really close. Why are they landing on a barge, though? Why not the middle of nowhere, on solid ground, where it would be easier to land? I suppose the cleanup after a failed landing, but still...

Where's this middle-of-nowhere-on-solid-ground that you speak of?

Visualize in your head the flight trajectory of the rocket and the geographic location of the launch site, and then think about your question again...

Makes me think they did the suicide burn too early and scrubbed off too much speed. But then that is better than doing the suicide burn too late. Holes in the recovery barge an all...

Nope, look at the video. The rocket is coming down fairly fast and actually throttles up shortly before touchdown. That's likely on purpose, too - they do an early landing burn at minimum throttle which is intentionally a little bit too weak to slow the vehicle down in time, and then start the real "suicide burn" only a few meters above the ground by throttling up when the margin of error is minimized. Gives them extra time too if the engine fails to start to try and ignite some of the other engines in an emergency landing abort.

Vertical velocity was not an issue in this landing, horizontal velocity was - potentially due to oversteering with laggy controls.

Edited April 16, 2015 by Streetwind

[Starwhip]

Where's this middle-of-nowhere-on-solid-ground that you speak of?

Visualize in your head the flight trajectory of the rocket and the geographic location of the launch site, and then think about your question again...

Okay, fine. I admit that it might not be a good idea to fly over people.

Stupid civilization, always getting in the way of progress. Sometimes literally.

Two solutions.

Move the people.

Make the barge bigger.