Updates SpaceX Falcon 9 F5 CRS SpX-2 through CRS SpX-12 Updates

[MattBaker]

The problem of crash landing would be a serious one when returning to the actual launch pad obviously.

The problem of crash landing will be a much larger problem once SpaceX launches from Texas over Florida so the recovery of the first stage becomes easier. Wouldn't there always be some window where a failure would mean a (nearly) fully fueled second stage, including payload and a nearly empty first stage crash somewhere in Florida?

 

[Urwumpe]

The problem of crash landing will be a much larger problem once SpaceX launches from Texas over Florida so the recovery of the first stage becomes easier. Wouldn't there always be some window where a failure would mean a (nearly) fully fueled second stage, including payload and a nearly empty first stage crash somewhere in Florida?

Or Cuba. Which is also not that great.

 

[MattBaker]

Or Cuba. Which is also not that great.

I thought Cuba does not exist, fellow patriot.

 

[Urwumpe]

I thought Cuba does not exist, fellow patriot.

You mistake it for Bielefeld, which does indeed not exist, comrade. Cuba is where the cigars come from. :lol:

 

[Andy44]

The problem of crash landing will be a much larger problem once SpaceX launches from Texas over Florida so the recovery of the first stage becomes easier. Wouldn't there always be some window where a failure would mean a (nearly) fully fueled second stage, including payload and a nearly empty first stage crash somewhere in Florida?

I don't know how in the world a nearly full booster would ever make it across the Gulf of Mexico without burning most of its fuel. Especially with the rest of the launch vehicle and payload stacked on top...

 

[Urwumpe]

I don't know how in the world a nearly full booster would ever make it across the Gulf of Mexico without burning most of its fuel. Especially with the rest of the launch vehicle and payload stacked on top...

Second stage - not first stage. If the second stage was not separated before failure, you will crash it.

 

[Donamy]

Also wouldn't you launch with the trajectory away from populated areas, then change coarse, when you knew you had a stable first stage to return.

 

[Urwumpe]

If you can afford it. Dog-Leg-maneuvers are very expensive. And even if you have a stable burn, you can still have failures while being suborbital.

 

[Andy44]

Dog-leg after most of the fuel is burnt isn't too bad, though.

 

[Urwumpe]

Dog-leg after most of the fuel is burnt isn't too bad, though.

Its very bad actually, since you also have a higher velocity then and need more DV for changing course. Its a pretty optimization problem. The later you do it, the more DV you loose. If you do it as soon as possible, you weight more, but have too high gravity losses compared to a slightly later point.

 

[Andy44]

Its very bad actually, since you also have a higher velocity then and need more DV for changing course. Its a pretty optimization problem. The later you do it, the more DV you loose. If you do it as soon as possible, you weight more, but have too high gravity losses compared to a slightly later point.

Yeah, it depends on how far from the intended landing site you can do the sideways burn. You won't change the heading angle much with all that forward velocity, but your cross-track velocity can still be fairly large.

In any case if you want to recover a launch vehicle you're going to have to pay mass penalties somewhere.

Is it a fact that SpaceX plans to do the 2nd-stage-over-the-Gulf thing or this is still in the rumor/think-about-it phase?

 

[Donamy]

Bring the second stage to AOA

 

[Urwumpe]

Bring the second stage to AOA

If you can. Failures don't like appointments.

For planning aborts, you have to first identify what can go wrong - and then you have to look how likely it is. And next when it could happen, which harms you most. Only if it a harmless failure and does not affect your mission, its OK to ignore it. If you can't ignore it, iterate through the phases, how much you can still do to prevent loss of human life. Ideally, you keep the rocket intact, but that secondary to preventing some unnecessary law suit for you crashing into a residential area.

 

[Cosmic Penguin]

Speaking of the video of the Falcon 9 first stage touching down in water - a team of volunteers found out that many parts of it can be restored. It took some skills in video architecture way beyond my understanding and a lot of man-power, but here's the result! :thumbup:

 

[MattBaker]

Looks quite good, the legs seemed to have deployed and it seemed to have nearly stopped its descent, too.:thumbup:

 

[John_L]

I've been part of that team since nearly the beginning. Without getting into too much detail I can give an overview of what we've been doing the last month or so. Basically there's 3 types of frames in mpeg video I,P and B frames, I frames are basically a full frame. All the information to recreate an I-frame is stored within an I-frame. P frames snap a new frame and compare it to the previous I frame and keep only what's changed, and B frames do the same thing except bi-directionally. The layout is usually IBBPBBPBBPBBPBB and then repeats, so you only really get a full frame every 15 frames. Most of the data from the video is actually there, it's just that there's alot of corrupt macroblocks, so we've been manually reassigning macroblocks, a really tedious process, and sometimes telling the decoder to ignore a macroblock which sometimes causes whole sections to come back. Also, chroma and luma values have been corrupted, and we've been going in and adjusting those until the color and brightness values "look right". It's been a big project from a bunch of forum members volunteering time to work on the 13 or so I frames in the video. Also, there's no real tools for this sort of thing, but we were lucky enough to have Michael Niedermayer, current curator of the open source FFMPEG codec as a forum member, so we'd tell him what tools we needed (to reassign macroblocks or XOR luma/chroma bits, etc, and he'd code it into FFMPEG for us. Without his contributions this would have been impossible. SpaceX has also been supportive of our efforts and following our progress as well. It was really cool today to open my phone and see a tweet by Elon Musk tweeting out the url to the video today!

Hopefully we'll get better video on the next launch. Unfortunately, the weather was so bad that NASA couldn't safely get any planes or ships close enough to get a decent recording of the signal. It's been alot of work, and alot of fun to try and restore this historic video. Also, all are welcome, so any mpeg experts here are welcome to come over to nasaspaceflight.com and join the fun...!

Edit: Anyone interested in watching the unveiling of the new manned version of Dragon can tune in 10pm Eastern Time (GMT +5) to watch live:
http://www.space.com/26043-spacex-manned-dragon-spacecraft-unveiling-webcast.html

 

[RGClark]

...

Hopefully we'll get better video on the next launch. Unfortunately, the weather was so bad that NASA couldn't safely get any planes or ships close enough to get a decent recording of the signal. It's been alot of work, and alot of fun to try and restore this historic video. Also, all are welcome, so any mpeg experts here are welcome to come over to nasaspaceflight.com and join the fun...!

Could a more powerful transmitter on the stage have helped? Would it work to send the data via "satellite phone" link? Satellite phone data rates are rather low compared to usual cell phones but you might be able to break the data up among separate phone links.

Latest version of the restored landing video:

Bob Clark

 

[fsci123]

Spaceflight production at its best...
or
How nasa should build the orion...

 

[Kyle]

@flatoday_jdean
NASA's Dan Hartman: SpaceX-4 ISS resupply launch likely Sept. 18-19; then Orb-3 would be planned Oct. 21, but could go week earlier.

 

[Cosmic Penguin]

Currently SpaceX CRS-4 is tracking no earlier than September 19 at 2:38 am Eastern (06:38 UTC). 3.5 weeks pad turn around again? :hmm: