SpaceX Falcon Launch & Landing Attempt 5/27 5:40 PM

[PottedMeat]

Patrick Airforce Base weather forecast: http://www.patrick.af.mil/Portals/1... 15 June Launch.pdf?ver=2016-06-14-091006-907

weather looks like 80% go

cool looking stack, not as cool as the orbcomm one though

 

[Brovane]

cool looking stack, not as cool as the orbcomm one though

It is using Electric Propulsion to propel the two satellites to their final orbits. That is automatically cool.

 

[PottedMeat]

neat, they're doing full video from the 1st stage on the tech webcast

nevermind they stopped before the reentry burn

 

[PottedMeat]

damn the last shot was a standing rocket with lots of fire & smoke

 

[Thebobo]

Hmmm, wonder if something went bad.

 

[Brovane]

The most important item, did the payload make it to it's intended orbit.

 

[iamwiz82]

hasn't deployed payload yet

 

[PottedMeat]

aww they're saying it's probably destroyed

 

[Brovane]

aww they're saying it's probably destroyed

Elon confirmed on Twitter, RUD on the 1st stage. However they got more data to increase the odds of a successful landing in the future.

 

[tynopik]

Elon Musk ‏@elonmusk 1h1 hour ago

Looks like thrust was low on 1 of 3 landing engines. High g landings v sensitive to all engines operating at max.

 

[tynopik]

Elon Musk ‏@elonmusk 2h2 hours ago

Upgrades underway to enable rocket to compensate for a thrust shortfall on one of the three landing engines. Probably get there end of year.

Landing video will be posted when we gain access to cameras on the droneship later today. Maybe hardest impact to date. Droneship still ok.

https://www.youtube.com/watch?v=gLNmtUEvI5A&feature=player_detailpage#t=2172

 

[Red Squirrel]

Little thruster that couldn't

The problem here is that Jebediah Kerman was not the pilot.

 

[Linux23]

Computers are not smart. Bottom line is if a computer isn't programmed specifically for a problem then it will fail.

Is there a reason they are landing in the ocean?

 

[iamwiz82]

Computers are not smart. Bottom line is if a computer isn't programmed specifically for a problem then it will fail.

Is there a reason they are landing in the ocean?

Less chance of taking out a bus full of nuns.

 

[tynopik]

Is there a reason they are landing in the ocean?

Because they didn't have enough fuel to return to base

 

[Red Squirrel]

Because they didn't have enough fuel to return to base

Yeah by nature the fall in an arc (basically an uncompleted orbit) so it's easier and requires less fuel to just more or less continue that direction in a controlled matter then land it, than to turn around and bring it back. That, and less risk of harming anything or anyone. I'm guessing they probably set an exclusion zone for any boat activity in that area as well.

 

[Linux23]

OK. Understood. I hope the CPUs have enough power to correct for the variable wind speed at sea.

 

[Phoenix86]

Yeah by nature the fall in an arc (basically an uncompleted orbit) so it's easier and requires less fuel to just more or less continue that direction in a controlled matter then land it, than to turn around and bring it back. That, and less risk of harming anything or anyone. I'm guessing they probably set an exclusion zone for any boat activity in that area as well.

It's based on payload/final orbit. More fuel required at launch means less available for return, so ocean landing.

 

[Phoenix86]

OK. Understood. I hope the CPUs have enough power to correct for the variable wind speed at sea.

They do, but the programming needs tweaking. Only a handful of successful landings, or attempts really. The fact we aren't even focusing on the successful launches and just the return/landing is a massive step forward.

 

[Brovane]

OK. Understood. I hope the CPUs have enough power to correct for the variable wind speed at sea.

They do, SpaceX uses commercially available CPUs for it's flight computers which means they are much more powerful than the flight computers used in previous launch vehicles.

 

[Darwin333]

I have a dumb question. I understand how the 2nd stage puts the payload into an elliptical orbit and at the proper altitude/speed the satellites will use it's own thrusters to stabilize it's orbit/make it circular. So when the satellites are released the 2nd stage is still in this elliptical orbit, then what happens to it? Do they do another burn or do they let it keep on coasting until eventually it hits the atmosphere? If the latter does it hit the atmosphere on it's first orbit or does it take a few?

 

[Darwin333]

Computers are not smart. Bottom line is if a computer isn't programmed specifically for a problem then it will fail.

Is there a reason they are landing in the ocean?

Contrary to what most people think we don't send stuff into space by going straight up. You actually have to shoot the rocket more sideways then up to give it orbital speed. For geostationary launches the horizontal speed is even greater and by the time you release the 2nd stage it's speed and downrange distance is to great to return to the launch pad.

I'm sure there is also a safety reason as well but at least for geostationary launches it's just going to fast and to far downrange. Maybe a landing in another country would be feasible? I'm also not sure if it's trajectory would allow it to complete an orbit to try and bring it back to the launch pad either.

 

[Phoenix86]

Contrary to what most people think we don't send stuff into space by going straight up. You actually have to shoot the rocket more sideways then up to give it orbital speed. For geostationary launches the horizontal speed is even greater and by the time you release the 2nd stage it's speed and downrange distance is to great to return to the launch pad.

I'm sure there is also a safety reason as well but at least for geostationary launches it's just going to fast and to far downrange. Maybe a landing in another country would be feasible? I'm also not sure if it's trajectory would allow it to complete an orbit to try and bring it back to the launch pad either.

I believe re-entry would be a major problem to orbit once than come back, I don't think stage 1 goes that fast/far out of the atmosphere so shielding isn't that important.

 

[Brovane]

I have a dumb question. I understand how the 2nd stage puts the payload into an elliptical orbit and at the proper altitude/speed the satellites will use it's own thrusters to stabilize it's orbit/make it circular. So when the satellites are released the 2nd stage is still in this elliptical orbit, then what happens to it? Do they do another burn or do they let it keep on coasting until eventually it hits the atmosphere? If the latter does it hit the atmosphere on it's first orbit or does it take a few?

Depends on fuel reserves. If they can do a de-orbit burn they will. For GTO missions if they allow a natural decay it can take 2-6 months.

http://space.stackexchange.com/questions/7814/what-happens-to-the-falcon-9-second-stage-after-payload-separation

For the Delta-IV Heavy launch last week, since they did a direct to GSO insertion the 2nd stage is moved into what is called a grave-yard orbit and left their.

 

[Brovane]

I'm also not sure if it's trajectory would allow it to complete an orbit to try and bring it back to the launch pad either.

At staging the 1st stage is travelling at around ~8,000 km/hr, about ~27,000 km/hr is required for orbital velocity so doing one orbit isn't possible. Also the requirements for Thermal protection would increase significantly.