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#160
by
Chris Bergin
on 15 May, 2013 21:56
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Three hours to the second burn.
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#161
by
Star One
on 15 May, 2013 21:56
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Why a three hour coast phase?
That seems exceptionally long.
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#162
by
Overflow
on 15 May, 2013 21:57
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#163
by
BrightLight
on 15 May, 2013 21:57
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Thanks for the super coverage
97.36%
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#164
by
Chris Bergin
on 15 May, 2013 21:57
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Lt. Pond comes across as a great guy.
ULA Webcast ending until the end of the coast.
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#165
by
Overflow
on 15 May, 2013 21:58
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#166
by
Overflow
on 15 May, 2013 21:58
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#167
by
Chris Bergin
on 15 May, 2013 21:58
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#168
by
Targeteer
on 15 May, 2013 22:01
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10,980X90 NM orbit at 55 degrees. There were no target parameters for this stage in the mission guide
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#169
by
jcm
on 15 May, 2013 22:03
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Why a three hour coast phase?
That seems exceptionally long.
You are used to missions where MECO-1 leaves you in low LEO,
200 x 200 km or so, and then the second burn is to GTO (with a much later apogee burn to get to final orbit). So the coast phase then is just to get perigee on the equator, doesn't take long to get there.
But on this mission Atlas flew straight from the pad to transfer orbit,
167 x 20200 km x 55 deg. The second burn will circularize at 20200 km for the final target orbit. So the coast phase is just half the transfer orbit period - three hours is not bad to coast from 200 km or so all the way up to 20000 km or so.
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#170
by
Overflow
on 15 May, 2013 22:03
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#171
by
Targeteer
on 15 May, 2013 22:07
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Lt. Pond comes across as a great guy.
He's an AF Lt
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#172
by
Star One
on 15 May, 2013 22:07
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Why a three hour coast phase?
That seems exceptionally long.
You are used to missions where MECO-1 leaves you in low LEO,
200 x 200 km or so, and then the second burn is to GTO (with a much later apogee burn to get to final orbit). So the coast phase then is just to get perigee on the equator, doesn't take long to get there.
But on this mission Atlas flew straight from the pad to transfer orbit,
167 x 20200 km x 55 deg. The second burn will circularize at 20200 km for the final target orbit. So the coast phase is just half the transfer orbit period - three hours is not bad to coast from 200 km or so all the way up to 20000 km or so.
Thanks for that clarification. This site is great for learning stuff like this.
Was there any particular reason why they used a baseline 401 on this mission, considering the past launchers used for GPS?
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#173
by
Galactic Penguin SST
on 15 May, 2013 22:09
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How comes this launch is going on a baseline 401 yet the last launch was on an augmented Delta IV?
The Atlas V 401 has a better performance than the Delta IV Medium. For a GTO with delta-V to GSO = 1800 m/s:
AV 401: 4750 kg
DIVM: 4540 kg
DIVM+4/2: 6270 kg
So the performance required to lift the GPS IIF satellites must be only just beyond the capability of the DIVM.
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#174
by
Star One
on 15 May, 2013 22:13
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How comes this launch is going on a baseline 401 yet the last launch was on an augmented Delta IV?
The Atlas V 401 has a better performance than the Delta IV Medium. For a GTO with delta-V to GSO = 1800 m/s:
AV 401: 4750 kg
DIVM: 4540 kg
DIVM+4/2: 6270 kg
So the performance required to lift the GPS IIF satellites must be only just beyond the capability of the DIVM.
Are more launches planned for the GPS network on the 401?
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#175
by
jcm
on 15 May, 2013 22:22
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I am confused about the SVN number for this GPS bird.
I have:
IIF Flight IIF SV GPS SV
1 1 62
2 2 63
4 3 66 <-- this flight
3 4 65
I would have expected IIF SV-3 to be GPS SV 64, and IIF SV-5 to be GPS SV 66.
The overall and subseries SV numbers ran in tandem in previous subseries.
Are we confident that this bird is IIF SV-3 and SVN 66?
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#176
by
Targeteer
on 15 May, 2013 22:24
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How comes this launch is going on a baseline 401 yet the last launch was on an augmented Delta IV?
The Atlas V 401 has a better performance than the Delta IV Medium. For a GTO with delta-V to GSO = 1800 m/s:
AV 401: 4750 kg
DIVM: 4540 kg
DIVM+4/2: 6270 kg
So the performance required to lift the GPS IIF satellites must be only just beyond the capability of the DIVM.
Are more launches planned for the GPS network on the 401?
According to the US launch schedule here,
http://forum.nasaspaceflight.com/index.php?topic=8184.msg1052295;boardseen#newI saw at least two next year
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#177
by
Jim
on 15 May, 2013 22:25
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From 8200 ft away and Iphone.
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#178
by
Targeteer
on 15 May, 2013 22:28
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From 8200 ft away and Iphone.
Could you feel the launch from there ?
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#179
by
Overflow
on 15 May, 2013 22:30
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From 8200 ft away and Iphone.
Nice!
