

Orbcomm satellite in wrong orbit after Falcon 9 launch  - someperson
http://spaceflightnow.com/falcon9/004/121008orbcomm/

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Gravityloss
The Falcon 9 upper stage didn't run out of propellant! It's that their ISS
safety window didn't permit refiring. Orbcomm said it in their own report:

"The OG2 prototype satellite, flying as a secondary payload on this mission,
was separated from the Falcon 9 launch vehicle at approximately 9:00 pm EST.
However, due to an anomaly on one of the Falcon 9’s first stage engines, the
rocket did not comply with a pre-planned International Space Station (ISS)
safety gate to allow it to execute the second burn. For this reason, the OG2
prototype satellite was deployed into an orbit that was lower than intended.
ORBCOMM and Sierra Nevada Corporation engineers have been in contact with the
satellite and are working to determine if and the extent to which the orbit
can be raised to an operational orbit using the satellite’s on-board
propulsion system"

[http://www.orbcomm.com/Collateral/Documents/English-
US/ORBCO...](http://www.orbcomm.com/Collateral/Documents/English-
US/ORBCOMM%20Launches%20Prototype%20OG2%20Satellite%20FINAL.pdf)

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smoyer
I found the article misleading as well ... if an engine was shut down, you'd
assume (with some margin of error) that the remaining 8 engines would fire
9/8th as long to provide the same total thrust and would therefore burn about
as much propellant as the original 9 engines.

~~~
jccooper
Orbital rendezvous with the ISS has a _very_ tight window (2.5-10 minutes),
since on-orbit propellant is very limited. They could add more, and make the
window a bit bigger, but that subtracts directly from cargo, which is already
small: just 1000 lbs.

The launcher has to drop Dragon basically right underneath the ISS; it
approaches by raising altitude just several km. (In orbit, speeding up or
slowing down means a change in altitude as well, so catching up or slowing
down requires a lot more fuel.)

Since the second stage drops off Dragon just below and a little behind the
ISS, a second burn to raise the orbit would necessarily take it past the ISS.
NASA is, understandably, very cautious around the ISS. I'm a bit surprised the
even allowed a secondary payload boost. It was probably on very, very tight
conditions.

Making up for the lost engine probably got them to about the right place, but
the different flight profile meant it wasn't the perfect place. Presumably it
was inside Dragon's maneuver window, but outside the parameters NASA set for
the secondary payload. This could happen if the second stage got too far
"ahead" of the ISS due to a longer, lower burn, putting the second stage stack
immediately below the ISS instead of below and behind it. Dragon, being in a
lower (slower) orbit, can just wait a bit and get in the right position, but
the booster could not proceed immediately as it would go too close to the ISS
and could not wait as it is battery powered. Thus: secondary payload doesn't
get its orbit.

Missing the secondary's orbit is unfortunate, but that is the nature of the
secondary payload. You take a gamble in return for a discounted ride. It's
appropriate for a prototype, as this is, and they'll probably still get their
primary mission done--testing that it functions properly in orbit. Probably
won't get to use it in their constellation if it works, which would have been
gravy.

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jonathlee
Based on the wording of the article, it seems that the satellite is in the
wrong orbit not because of the fault with the first stage but because the
second stage wasn't allowed to make a correction burn due to NASA rules.

~~~
peeters
I'm not that well informed here, but my guess is it was a combination of both.
They mention

> the extra burn time [of the first stage] left the rocket with insufficient
> propellant to safely place the Orbcomm satellite into a higher orbit.

I take that to mean that at the time when the first stage ran out of fuel,
they were still within the "no-space-junk" threshold where they weren't
allowed to separate/jettison the first stage (if that's how it works).

If the first stage had gone smoothly and left them with enough propellant,
they would have used that propellant to climb out of ISS danger zone, and then
fire the second stage safely.

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someperson
Another good article:
[http://www.aviationweek.com/Blogs.aspx?plckBlogId=Blog:04ce3...](http://www.aviationweek.com/Blogs.aspx?plckBlogId=Blog:04ce340e-4b63-4d23-9695-d49ab661f385&plckPostId=Blog%3A04ce340e-4b63-4d23-9695-d49ab661f385Post%3Afdf0d27c-fdf2-4efb-a71f-8272017dbfc3)

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sneak
Does this mean that the SpaceX statement yesterday along the lines of "it
worked as designed" was false, or did they just lie by omission of the fact
that they didn't launch it high enough?

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cryptoz
I don't think they have addressed this issue yet. When they said things like
"Falcon 9 did exactly what it was designed to do", all of that is 100% true.
Additionally, all comments SpaceX have made so far, I think, are written about
the ISS mission. They have not said anything about success or failure of other
aspects of the launch, like this satellite. I assume we'll hear something
eventually, but given that everything might be fine (the Orbcomm people are
working to get it in the right orbit, it sounds like) they're probably just
sitting tight for now.

~~~
axusgrad
Even if the satellite can propel itself to the correct orbit, it may burn a
lot of fuel which can take years off the operational life of the satellite.
Those years are worth a lot of money.

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tocomment
Does anyone know why the Orbcomm needs such a specific orbit? If it's in orbit
at all can't it do most of whatever it is supposed to do?

(Sorry probably a dumb question, huh)

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smackfu
It's got to suck working on making a satellite, with precision engineering and
the highest quality materials, to just have it go nowhere.

~~~
damoncali
Most space hardware is made from very ordinary materials, for what it's worth.
Lots of aluminum.

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smackfu
I was thinking of some of the fancy aluminium-lithium alloys, but I guess they
are mainly used on the rocket bodies, not the satellites. But even if it's
just aluminium, that's a lot of high-spec machining and welding to just burn
up.

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chucknelson
So can the orbit be corrected, or is this satellite just lost?

~~~
Breakthrough
It can be corrected, but only to the extent of how much fuel/propellant is
available on the satellite's on-board propulsion system... And when I mean
"available", I mean "available within the new amount of distance the orbit has
to be raised". From the article:

"It's possible but unlikely that the satellite has enough spare propellant to
complete its mission," McDowell wrote in an email to Spaceflight Now.

