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Orbcomm OG2 Falcon 9 Satellite Launch

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Re: Orbcomm OG2 Falcon 9 Satellite Launch

#14
post #2

This is the fourth separate attempt at launching this mission. The first one was more than a month ago. Their biggest problem are helium leaks. Successful launch. We can expect better video footage of the first stage landing.

So what happened on the first 3? Crashes?

Re: Orbcomm OG2 Falcon 9 Satellite Launch

#15
This launch seemed to use a much steeper trajectory. Typically they go downrange much faster than they gain altitude, but today they seemed to go up faster than they were going downrange.

How does this affect the fuel efficiency of the launch? Is this a way to cut down the horizontal velocity so they first stage can return more easily?

Re: Orbcomm OG2 Falcon 9 Satellite Launch

#16
post #14
post #2

This is the fourth separate attempt at launching this mission. The first one was more than a month ago. Their biggest problem are helium leaks. Successful launch. We can expect better video footage of the first stage landing.

So what happened on the first 3? Crashes?

Here is the video of the previous one. It landed.

https://www.youtube.com/watch?v=CjZ33C9JZTM

Video was barely recognizable before repair.

Re: Orbcomm OG2 Falcon 9 Satellite Launch

#17
post #16
post #14

Earlier quoted context omitted.

So what happened on the first 3? Crashes?

Here is the video of the previous one. It landed. https://www.youtube.com/watch?v=CjZ33C9JZTM Video was barely recognizable before repair.

That was a different mission.

Re: Orbcomm OG2 Falcon 9 Satellite Launch

#18
post #14
post #2

This is the fourth separate attempt at launching this mission. The first one was more than a month ago. Their biggest problem are helium leaks. Successful launch. We can expect better video footage of the first stage landing.

So what happened on the first 3? Crashes?

No, aborted before launch.

Re: Orbcomm OG2 Falcon 9 Satellite Launch

#19

This launch seemed to use a much steeper trajectory. Typically they go downrange much faster than they gain altitude, but today they seemed to go up faster than they were going downrange. How does this affect the fuel efficiency of the launch? Is this a way to cut down the horizontal velocity so they first stage can return more easily?

Maybe. This time, the satellite load was just 1.1 tonnes (vs. 6 tonnes capacity), so they probably had more room for maneuvering and hence decided to do stage separation closer to the launch site in order to aid with the recovery attempt. Or maybe it's standard procedure on lighter payloads; perhaps it reduces maximum dynamic pressure.

Re: Orbcomm OG2 Falcon 9 Satellite Launch

#20

This launch seemed to use a much steeper trajectory. Typically they go downrange much faster than they gain altitude, but today they seemed to go up faster than they were going downrange. How does this affect the fuel efficiency of the launch? Is this a way to cut down the horizontal velocity so they first stage can return more easily?

It's a product of a higher target altitude (650km for Orbcomm vs. 330km for an ISS resupply) and wanting to perform a single second-stage burn to achieve the target orbit.
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