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SES-8 – Falcon 9 GEO Transfer Mission (spacex.com)
104 points by nakkiel on Dec 3, 2013 | hide | past | favorite | 38 comments



I know HN readers have a love affair with SpaceX but my dad's company is launching a rocket on Thurs at Vandenberg and it should be fun to watch:

http://www.noozhawk.com/article/atlas_v_set_for_launch_from_...


The Atlas V uses the very cool Russian designed RD-180 engine: http://en.wikipedia.org/wiki/RD-180

The documentary The Engines That Came in from the Cold is an interesting look at these engines and the NK-33's, and US/Russian collaboration.


I'd also like to add that Orbital Sciences is another great space launch company that's often forgotten about. They're HQ is also on "Warp Dr.".


Launch, MECO, stage sep, second stage is running now.

Update: Second stage engine cutoff (SECO), now coasting until second stage reignition.

Update 2: Second stage reignition should occur at 3:08pm PST (about 6 minutes from now) and burn for about 1min 11 seconds.

Update 3: "second stage restart burn successful. Orbit looks nominal" - @SpaceX

Update 4: "Spacecraft separation confirmed! SES-8 is now in its targeted GEO transfer orbit." - @SpaceX


Saw the 1st stage doing some RCS maneuvers right after separation, but they cut the camera away from that shot pretty quick so I couldn't see exactly what. They're not supposed to be trying to "land" this one, but I bet they're getting aero data in support of the F9-R.

All in all, looks like a good launch. Can't wait to hear about the second burn, which was last flight's sticking point.


Here, look at the left frame at about 3:30. It looks like RCS maneuvers, some guy on reddit claims he saw a relight from his backyard but its not visible in the official video.

http://youtu.be/cXEJLhAh-Kg?t=3m15s


A bit better. Yeah, that stage was working pretty hard on something. Hard to say but it may have been turning around, like the F9R would for its first retro burn. Some extra practice wouldn't hurt.


They turned it around to see when it falls apart if not re-lit but falling down the right way (engines first).


Possibly just insuring it lands in designated area, so it does not land on anything important and they do not have to search for it.


Somehow I forgot to mention Elon Musk's Twitter feed: https://twitter.com/elonmusk. Always a good read.


Very interesting, often a source of insights into what's really going on.

Plus, he's rarely wrong


Velocity of 1.2km/s - rockets are just awesome.


It'll have to go over 7km/s to reach low Earth orbit, and even faster still to complete it's mission to the geostationary satellite belt.

http://en.wikipedia.org/wiki/Geostationary_orbit


As Randall Munroe says:

  But getting to space is easy. The problem is staying there.
http://what-if.xkcd.com/58/


Edit: I'm going to try to rephrase this whole question since it got so unpopular. (I also said moon when I meant sun)

Lets say we fly a rocket up to earth sun L4 at a really slow speed. When we reach L4 we fire retro rockets to slow down as to not overshoot.

It seems to me that we never have to reach a high speed to stay in space at that point. The two bodies would be holding us there?

Is that correct? Is there a certain speed to fly out to L4 which uses less fuel than speeding up to 8km/s like you would need to stay in space orbiting earth?


The most efficient way to get from low Earth orbit to a point further away from Earth is with a single burn of your rocket engine. This burn close to Earth launches your rocket on a ballistic curve to the target point, with the least energy on arrival at the target (slowest speed) necessary to get there. Necessarily, this means you start off going fast after the initial burn and you slow down due to Earth's gravity as your altitude increases.

Trying to do it more slowly will just waste fuel. It would mean burning your engine less when close to Earth, not enough to reach your destination, then burning it again at higher altitude to stop Earth's gravity pulling you back down again. To understand why this is less efficient, check out the Oberth Effect (1). Trying to get to a distant point like the Earth-Sun L4 point doesn't fundamentally change any of this.

(1) http://en.wikipedia.org/wiki/Oberth_effect


If you did that you would have a huge relative velocity to the Lagrange point. You'd shoot right past it unless you could kill all your relative velocity, which would mean you would have enough delta-v to achieve orbit anyway.


I updated my question to explain it better I think.


It takes more speed to get high enough to reach an Earth-Moon lagrange point (L1 would be the closest, at about 90% of the Earth-Moon distance) than to simply get into Earth orbit.


Best of luck to the SpaceX team! Hopefully they got everything fixed!


Here we go again! I hope it happens this time!


Flight Update Falcon 9 and SES-8 satellite currently in parking orbit, awaiting second burn. All systems nominal.


Stream has started, launch in T-00:15:30.


Aaaand liftoff! Glad to see that it went off without a hitch this time (so far).


although all the rain on the camera makes it difficult to watch :(


Just curious, what is the purpose of the 4 towers around the launchpad?


Lightning rods


Trivia: Apollo 12 was struck by lightning, twice, after leaving the pad.

http://www.nasa.gov/offices/oce/appel/ask-academy/issues/vol...

This knocked out command module electrical systems, and it took some damned fast thinking from ECOM (electrical and environmental systems) who recalled an earlier incident and gave the instruction "SCE to AUX", resetting electrical systems.

Actual launch: http://fixyt.com/watch?v=eWQIryll8y8

Dramatization: http://fixyt.com/watch?v=TMYNy3JsHTE


After sitting through both launch attempts, I missed this one. Is there any way to view the launch video?


Check youtube, there are already several uploads of the video there.


So far a success, congrats SpaceX team!


Anyone know the details of the music Spacex used on the feed when not broadcasting?


Anyone know how long until they attempt the second stage restart?


Apparently it should at about T+30 min (seen on the SpaceX subreddit, so I don't know if it's accurate).


"At T+27 minutes, 2nd stage engine will reignite for ~1 minute. At T+33 minutes, spacecraft separation"


Thanks!

Reddit open thread for this launch: http://www.reddit.com/r/spacex/comments/1ryy1n/rspacex_falco...


Ignition is around 42:20 relative to the stream beginning.


Good Luck SpaceX




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