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Orbcomm OG2 Falcon 9 Satellite Launch

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Re: Orbcomm OG2 Falcon 9 Satellite Launch

#51
post #44
post #12

Watching the camera feed of the launch around the 5 minute mark all I could think was: if the rocket turned around now, it could probably land in New York in another 5 minutes

On a ballistic trajectory, you can reach anywhere on Earth in 40 minutes or less. I've seen cute little diagrams of the relevant times before, but I wasn't able to quickly Google one up.

Everyone who grew up during the Cold War knows this instinctively!

Re: Orbcomm OG2 Falcon 9 Satellite Launch

#52

Is this the re-usable launch vehicle, i.e. the one that re-enters the atmosphere and lands itself upright?

SpaceX only has one launcher at present, the difference between re-use and expendable use is a matter of how that hardware is used, not how it's built. Every Falcon 9 v1.1 launch to date has made use of the same, fundamentally reusable first stage core. To actually reuse the core requires bolting on some additional hardware (which has flown on 2 flights already) such as landing legs and then flying the stage back to land. In software terms this is like hiding new functionality behind a "feature flag" so that you can let the code bake in production for a while.

Re: Orbcomm OG2 Falcon 9 Satellite Launch

#53

Awesome! Are they going to repeat the launch for the west coast?

Their launch manifest (http://www.spacex.com/missions) lists one more launch from Vandenberg in 2014, and a few more in 2015. Eventually, if everything goes according to their plans, they will be doing regular launches from the west coast. (Which site they use is determined by which sort of orbit they are shooting for. They will launch from Vandenberg whenever appropriate. Vandenberg is typically used for high-inclination/polar orbits, or the rare retrograde orbit)

Re: Orbcomm OG2 Falcon 9 Satellite Launch

#54
post #3

Wow I can't believe this finally launched. So far so good! And of course, the most exciting thing about this is the return attempt of the F9 first stage core. I don't think that'll be covered in the webcast but we'll certainly get video of it later. MECO successful. Edit: r/spacex has good updates regarding the landing attempt [T+27m]: Elon's jet and NASA plane circling a particular area... http://www.reddit.com/r/sp…

Awesome, I noticed they were tracking the landing leg attachment points at liftoff, so perhaps there is a new leg deployment system. Also the note that 'kaboom' after splashdown suggests that some part of the landing mechanism didn't deal well the transition from flight to sailing. One wonders what the temperature differential is between the landing first stage and the ocean, on the one hand it might be hot (burning…

Like trothamel commented below, the stage isn't designed for tipping over and slamming into the water.

Re: Orbcomm OG2 Falcon 9 Satellite Launch

#55
I have nothing at stake in these launches but every one of them makes me nervous, I almost can't watch them. At any moment, boom.

The launch video was beautiful though, the water vaporizing and forming a could around the rocket is awesome, the inside view of the engine was amazing.

Can't wait to see the landing video!

What about the location of the landings? Have they been on target?

Re: Orbcomm OG2 Falcon 9 Satellite Launch

#56
post #54

Earlier quoted context omitted.

Awesome, I noticed they were tracking the landing leg attachment points at liftoff, so perhaps there is a new leg deployment system. Also the note that 'kaboom' after splashdown suggests that some part of the landing mechanism didn't deal well the transition from flight to sailing. One wonders what the temperature differential is between the landing first stage and the ocean, on the one hand it might be hot (burning…

Like trothamel commented below, the stage isn't designed for tipping over and slamming into the water.

My problem with that theory/scenario is that the stage is designed to land on its legs. When the test vehicles land they have very little angular momentum, presumably these tests would mimic that. And if the momementum was managed, then at engine shut off it would drop vertically into the water, and then fall over as the counter pressure of buouancy was not stabilized by the landing legs.

If you've ever seen loggers drop tree trunks in a river you can imagine what that looks like, it starts out vertical, then reaches point where it displaces enough water that it is essentially floating (but unstably so) and then rotates to horizontal around the point on the trunk that is at the surface of the water.

I totally understand that this isn't an intended landing mode :-).

Thinking about how they manage fuel load, it made me wonder how I would do it, do you hover until you've exhausted all fuel? Or do you just shut off the engine? And at flameout are you out of volatiles or just some volatiles (like LOX)and do you have the 'gas tank' issue that auto mechanics deal with where residual vapors can be explosive.

Would love to sit through the briefings on this stuff.

Re: Orbcomm OG2 Falcon 9 Satellite Launch

#57
post #55

I have nothing at stake in these launches but every one of them makes me nervous, I almost can't watch them. At any moment, boom. The launch video was beautiful though, the water vaporizing and forming a could around the rocket is awesome, the inside view of the engine was amazing. Can't wait to see the landing video! What about the location of the landings? Have they been on target?

They seem to be having consistent results (modulo the landings), so it's almost safe to take a successful launch for granted (at least for people like us who are just watching).

Re: Orbcomm OG2 Falcon 9 Satellite Launch

#58
post #54

Earlier quoted context omitted.

Like trothamel commented below, the stage isn't designed for tipping over and slamming into the water.

My problem with that theory/scenario is that the stage is designed to land on its legs. When the test vehicles land they have very little angular momentum, presumably these tests would mimic that. And if the momementum was managed, then at engine shut off it would drop vertically into the water, and then fall over as the counter pressure of buouancy was not stabilized by the landing legs. If you've ever seen loggers…

The problem with your picture is that the empty stage is extremely light for its volume so, unlike a log, it floats very high in the water. Floating upright, most of it is above water and the top of the rocket is high above the water. The full launch vehicle is 220ft tall, and 2/3 of that is the first stage.

Re: Orbcomm OG2 Falcon 9 Satellite Launch

#59
post #3

Wow I can't believe this finally launched. So far so good! And of course, the most exciting thing about this is the return attempt of the F9 first stage core. I don't think that'll be covered in the webcast but we'll certainly get video of it later. MECO successful. Edit: r/spacex has good updates regarding the landing attempt [T+27m]: Elon's jet and NASA plane circling a particular area... http://www.reddit.com/r/sp…

Awesome, I noticed they were tracking the landing leg attachment points at liftoff, so perhaps there is a new leg deployment system. Also the note that 'kaboom' after splashdown suggests that some part of the landing mechanism didn't deal well the transition from flight to sailing. One wonders what the temperature differential is between the landing first stage and the ocean, on the one hand it might be hot (burning…

> tracking the landing leg attachment points at liftoff

I suspect its more to do with that being where the giant spacex logo is painted on.

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