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#340
by
robertross
on 18 Nov, 2013 18:20
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and we have separation!!
Congrats ULA!! Great job.
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#341
by
Ford Mustang
on 18 Nov, 2013 18:21
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Spacecraft separation! Congratulations Atlas, MAVEN, and all involved! We're off to Mars!
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#342
by
AJA
on 18 Nov, 2013 18:21
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Body rates nulled out at 0
Attitude for sep achieved.
I smiled at the CGI orbital sunrise.
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#343
by
Robotbeat
on 18 Nov, 2013 18:21
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Payload sep, we're on our way to Mars!
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#344
by
Chris Bergin
on 18 Nov, 2013 18:21
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S/C Sep!!
Congrats to all involved!
So incredibly smooth.
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#345
by
Targeteer
on 18 Nov, 2013 18:21
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no rocketcams
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#346
by
robertross
on 18 Nov, 2013 18:21
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commentary concluding
LD to be on shortly
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#347
by
Star One
on 18 Nov, 2013 18:22
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That's that, plenty of handshakes all round.
Congratulations to all involved.
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#348
by
Chris Bergin
on 18 Nov, 2013 18:22
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#349
by
Ford Mustang
on 18 Nov, 2013 18:22
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Congrats to all, again. Thanks for everyone chipping in on the live coverage! See you guys next time.
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#350
by
Targeteer
on 18 Nov, 2013 18:22
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post launch presser at 4 pm
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#351
by
Jim
on 18 Nov, 2013 18:23
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Good so far...
A question re: Centaur - Does it not gimbal? I'm always surprised by the large # of RCS firings during Centaur burns.
it does gimbal, firings are for roll and minor tweaks. Also, there is burn off of the margin, which helps with performance.
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#352
by
Lars_J
on 18 Nov, 2013 18:23
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Thanks, Jim.
Nice job ULA, making it look easy as usual!
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#353
by
AJA
on 18 Nov, 2013 18:25
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Good so far...
A question re: Centaur - Does it not gimbal? I'm always surprised by the large # of RCS firings during Centaur burns.
it does gimbal, firings are for roll and minor tweaks. Also, there is burn off of the margin, which helps with performance.
Jim, doesn't it also help force the cryogenic propellant toward the bottom of their tanks? I thought prop settling referred to that
And we're not going ot have solar array deployment confirmation / comms confirmation until 4 pm EST?
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#354
by
PahTo
on 18 Nov, 2013 18:25
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Good deal! So what happens to the Centaur? Perhaps related, why the nearly 6 minute delay between Rl-10 burn number 2 and spacecraft sep?
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#355
by
ClayJar
on 18 Nov, 2013 18:25
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Apogee skyrocketed and has now gone negative. Presumably we've reached escape velocity.
Is that what happens when it reaches escape velocity?
The display showed negative the radius of the earth in nautical miles, so apparently when you reach escape velocity, it just uses the center of the earth instead of messing with infinities.
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#356
by
Rocket Science
on 18 Nov, 2013 18:26
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On to Mars! Congrats and well done!!
Thanks for the great coverage NSF as usual.
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#357
by
Satori
on 18 Nov, 2013 18:28
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Exact launch time... 1828:00.267UTC.
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#358
by
ugordan
on 18 Nov, 2013 18:30
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Good so far...
A question re: Centaur - Does it not gimbal? I'm always surprised by the large # of RCS firings during Centaur burns.
it does gimbal, firings are for roll and minor tweaks. Also, there is burn off of the margin, which helps with performance.
An unrelated Atlas question: what determines the point when the booster goes to closed loop propellant utilization control? This launch seemed to show a PU shift (exhaust getting more "flamey") very shortly after clearing the towers, usually it seems to happen closer to going supersonic.
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#359
by
jcm
on 18 Nov, 2013 18:31
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Apogee skyrocketed and has now gone negative. Presumably we've reached escape velocity.
Is that what happens when it reaches escape velocity?
The display showed negative the radius of the earth in nautical miles, so apparently when you reach escape velocity, it just uses the center of the earth instead of messing with infinities.
No - it's a formal definition of the apogee for hyperbolic orbits.
The semi-major axis, a, is equal to (apogee+perigee)/2 + radius of earth for a bound orbit.
For a hyperbolic orbit it is still well defined, and negative (passes through infinity and then comes down from minus
infinity, so an orbit with a= -100000 is LESS hyperbolic than one with a = -1000
Then our formal definition of perigee still works:
perigee = a(1-e) - R(Earth) (e is the eccentricity, now > 1) is still the actual perigee height
so if we do the same for apogee
apogee = a(1+e)- R(Earth)
we get a negative number that is fairly devoid of physical interpretation but still useful to have, since
we can plug in the usual formulae to recover a, e, etc.
