SpaceX Falcon 9 v1.1 - SES-8 - DISCUSSION THREAD

[Roy_H]

I am presuming that the relight will come as the stage and payload pass over the Equator.

As I understand it, they are aiming for an orbit with a 19 degree inclination, so I would expect the relight to happen earlier.

[Roy_H]

Relight successful!

[Lars_J]

I am presuming that the relight will come as the stage and payload pass over the Equator.

As I understand it, they are aiming for an orbit with a 19 degree inclination, so I would expect the relight to happen earlier.

No, the most efficient place for the combined burn to raise apogee and change inclination is at the equator. And they care more about the location of the apogee than they do about the specific inclination.

And Elon tweeted: https://twitter.com/elonmusk/status/408008759433502720

Elon Musk ‏@elonmusk
Reached parking orbit. Now coasting towards equator, where the upper stage will, if all goes well, restart to raise apogee

[IRobot]

What happens to the 2nd stage now? trails behind SES forever or does a 3rd burn to reenter?

[jongoff]

Did separation actually get confirmed? Someone said it was confirmed here, but I didn't actually see a post saying that...

~Jon

[jongoff]

And of course just after saying that:
SpaceX ‏@SpaceX 9s

Spacecraft separation confirmed! SES-8 is now in its targeted GEO transfer orbit.

[Lars_J]

What happens to the 2nd stage now? trails behind SES forever or does a 3rd burn to reenter?

I think it will trail behind for now (until SES-8 does its apogee burn) and with its low perigee it should reenter at some point in the not too distant future. (not sure how many orbits, but it should be a lot)

[QuantumG]

What happens to the 2nd stage now? trails behind SES forever or does a 3rd burn to reenter?

I don't believe they intend to deliberately deorbit it.

What's the perigee? Should be able to figure out when it'll eventually come down.

[Helodriver]

With the very visible 1st stage RCS firings after staging, I hope they got some good data and practice controlling the stage orientation for future landings. I wonder if what they did will be addressed post launch sometime?

[jongoff]

Peter B. de Selding ‏@pbdes 12s

SES has acquired spacecraft and it is in good health.

[IRobot]

What happens to the 2nd stage now? trails behind SES forever or does a 3rd burn to reenter?

I don't believe they intend to deliberately deorbit it.

What's the perigee? Should be able to figure out when it'll eventually come down.

A 3rd restart would prove multiple restart capability. They will need it eventually.

[bioelectromechanic]

Is there a post launch conference planned? when?

[QuantumG]

I'm under the impression that to execute a mission like this while recovering the first stage, a Falcon Heavy would be necessary, right ?

Nope. SpaceX can fly a GTO mission on Falcon 9 v1.1 and recover the first stage. They didn't on this flight because it was their first and they wanted to dedicate as much margin as possible to the flight trajectory.

[Robotbeat]

I'm under the impression that to execute a mission like this while recovering the first stage, a Falcon Heavy would be necessary, right ?

No, F9R is enough. SpaceX just did not want to risk it and gave full 1st stage performance.

Are you sure? You may be right, but I'd like some sort of confirmation. Some GTO missions might not provide enough performance to do a RTLS. It could be they might be able to recover stages from the ocean as an intermediate step, but I'm not even sure that's feasible here.

In any case, a higher energy upper stage would allow first stage recovery even with big GTO payloads.

[butters]

Now they'd want to get a handle on how much residual prop they have in the upper stage, to refine their performance margins.

[Lars_J]

A cool view of the launch:

I wonder, is this after MVac ignition, or is it all first stage?

[IRobot]

I'm under the impression that to execute a mission like this while recovering the first stage, a Falcon Heavy would be necessary, right ?

No, F9R is enough. SpaceX just did not want to risk it and gave full 1st stage performance.

Are you sure? You may be right, but I'd like some sort of confirmation. Some GTO missions might not provide enough performance to do a RTLS. It could be they might be able to recover stages from the ocean as an intermediate step, but I'm not even sure that's feasible here.

That is what I understand from this:

Musk indicated that SpaceX would not attempt to recover the first stage for the SES and Thaicom flights, instead “(for) the next two launches, we are going to gather data from the first stage but we are not going to attempt to recover it because we’ve committed to give the customers on the next two flights maximum performance of the rocket. The next recovery attempt for the first stage will be the fourth flight of this version.”

http://www.nasaspaceflight.com/2013/10/ses-8-florida-next-falcon-9-v1-1-launch/

EDIT: and here http://forum.nasaspaceflight.com/index.php?topic=24469.465

[Lars_J]

If anyone missed it on the update thread, here is a Youtube replay of the launch:
(And at 3:20 we get a very clear view of the first stage RCS firing)



I've attached an image... The blue exhaust is definitely the RCS, the white may just be M1D or tank venting:

[Herb Schaltegger]

I'm under the impression that to execute a mission like this while recovering the first stage, a Falcon Heavy would be necessary, right ?

No, F9R is enough. SpaceX just did not want to risk it and gave full 1st stage performance.

Are you sure? You may be right, but I'd like some sort of confirmation. Some GTO missions might not provide enough performance to do a RTLS. It could be they might be able to recover stages from the ocean as an intermediate step, but I'm not even sure that's feasible here.

Indeed. The most recently-flown Directv satellites were Boeing 702's. Each massed over 6,000 kg at launch, almost twice the mass of SES-8. That is well above Falcon 9's stated payload to GTO of 4,850 kg.

[QuantumG]

and also:

The next two flights are somewhat of an exception. When we negotiated these deals, we didn't have much bargaining power. It was before we obviously flown this version of the Falcon 9 successfully. So we kind of agreed to give up all performance on the rocket and not reserve anything for reusability. But going into the future, with future contracts, with a few exceptions, we have reserved enough performance to recover the stage.

http://shitelonsays.com/transcript/spacex-press-conference-september-29-2013-2013-09-29