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#20
by
averagespacejoe
on 21 Mar, 2015 15:21
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This is the best image of the patch I got Not digital but maybe that will come out after launch.
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#21
by
beidou
on 21 Mar, 2015 17:47
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#22
by
Billium
on 22 Mar, 2015 17:48
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Please indulge what is surely a dumb question. Wikipedia lists Delta IV medium payload capacity at 4,200kg to GTO and Delta IV medium+ (4,2) payload capacity at 6,150kg to GTO. Wikipedia also lists the mass of GPS block IIF at 1,630kg going to MEO. Is MEO a higher energy orbit than GTO, does Wikipedia have the numbers wrong, could ULA use a Delta IV medium without the +? I guess the MEO orbit is higher energy. Thanks in advance.
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#23
by
Jim
on 22 Mar, 2015 18:15
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Please indulge what is surely a dumb question. Wikipedia lists Delta IV medium payload capacity at 4,200kg to GTO and Delta IV medium+ (4,2) payload capacity at 6,150kg to GTO. Wikipedia also lists the mass of GPS block IIF at 1,630kg going to MEO. Is MEO a higher energy orbit than GTO, does Wikipedia have the numbers wrong, could ULA use a Delta IV medium without the +? I guess the MEO orbit is higher energy. Thanks in advance.
The GPS mission is a 3 burn for the upper stage and places the spacecraft in the final orbit. GTO is not the final orbit for spacecraft and the spacecraft has to perform apogee burns.
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#24
by
edkyle99
on 22 Mar, 2015 19:57
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Please indulge what is surely a dumb question. Wikipedia lists Delta IV medium payload capacity at 4,200kg to GTO and Delta IV medium+ (4,2) payload capacity at 6,150kg to GTO. Wikipedia also lists the mass of GPS block IIF at 1,630kg going to MEO. Is MEO a higher energy orbit than GTO, does Wikipedia have the numbers wrong, could ULA use a Delta IV medium without the +? I guess the MEO orbit is higher energy. Thanks in advance.
The mission is directly to a 20,368 x 20,368 km x 55 deg GPS orbit, which does require more delta-v than a geosynchronous transfer orbit. Delta 4M+4,2 can lift 2.986 tonnes to this orbit, according to the 2007 User's Guide. Delta 4M was listed at 1.988 tonnes.
This does raise a question about why a straight Medium wasn't used. It likely has to do with desired margin and with the fact that the User's Guide numbers include the mass of the payload attach fitting, which might weigh a couple hundred kg. It is also possible that (1) Delta 4 can't really do what the 2007 Guide said it could do or (2) that the satellite weighs more than we think.
- Ed Kyle
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#25
by
macpacheco
on 22 Mar, 2015 20:03
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Please indulge what is surely a dumb question. Wikipedia lists Delta IV medium payload capacity at 4,200kg to GTO and Delta IV medium+ (4,2) payload capacity at 6,150kg to GTO. Wikipedia also lists the mass of GPS block IIF at 1,630kg going to MEO. Is MEO a higher energy orbit than GTO, does Wikipedia have the numbers wrong, could ULA use a Delta IV medium without the +? I guess the MEO orbit is higher energy. Thanks in advance.
The mission is directly to a 20,368 x 20,368 km x 55 deg GPS orbit, which does require more delta-v than a geosynchronous transfer orbit. Delta 4M+4,2 can lift 2.986 tonnes to this orbit, according to the 2007 User's Guide. Delta 4M was listed at 1.988 tonnes.
This does raise a question about why a straight Medium wasn't used. It likely has to do with desired margin and with the fact that the User's Guide numbers include the mass of the payload attach fitting, which might weigh a couple hundred kg. It is also possible that (1) Delta 4 can't really do what the 2007 Guide said it could do or (2) that the satellite weighs more than we think.
- Ed Kyle
Perhaps something to do with the target orbital plane ? Some orbital planes align almost perfectly with a launch from the cape, others don't. I'll be corrected in 10,9,8,7,6,5,4,3,2,1,launch
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#26
by
chewi
on 23 Mar, 2015 05:29
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#27
by
jacqmans
on 23 Mar, 2015 09:18
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Launch Mission Execution Forecast
Vehicle: Delta IV GPS IIF-9
Issued: 22 March 2015 / 1230Z (0830 EDT)
Valid: 25 March 2015 / 1832 – 1850Z (1432 – 1450 EDT)
Synoptic Discussion: A weak front will move into the area Monday bringing showers and just a slight chance of a thunderstorm. No severe weather is expected. The front will move off to the east Tuesday, and high pressure will build in to the north improving weather. On launch day, the high pressure area to the north will move east causing winds to shift to the southeast and increase through the day. The onshore wind along with low-level moisture will cause isolated morning coastal showers, but showers will decrease by the afternoon launch window. The primary concerns for launch are flight through precipitation and cumulus clouds. Thursday, gusty winds are expected in the morning, but as the high to the east moves away the wind speed will shift southwest and decrease. The moisture in the atmosphere deepens as well, and there is a chance of cumulus clouds with precipitation to develop along the afternoon sea breeze. The primary concerns for a 24-hour delay are, again, flight through precipitation and cumulus clouds.
http://www.patrick.af.mil/shared/media/document/AFD-071220-067.pdf
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#28
by
douglas100
on 23 Mar, 2015 10:56
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Perhaps something to do with the target orbital plane ? Some orbital planes align almost perfectly with a launch from the cape, others don't. I'll be corrected in 10,9,8,7,6,5,4,3,2,1,launch
The rotation of the Earth ensures that CCAFS passes through
each plane of the constellation twice a day. So all planes are equally easy to reach. All that changes is the launch window.
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#29
by
kevin-rf
on 23 Mar, 2015 11:13
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Not if you are aiming for a specific slot in the plane.
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#30
by
macpacheco
on 23 Mar, 2015 15:00
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Not if you are aiming for a specific slot in the plane.
Nope, getting to the specific slot is easy once on the right plane.
GPS injections are executed on a higher orbit, like 100Km too high, too high = slower, so the injection is already to an orbit where all they need to do is leave the bird alone while it moves westward compared to other birds, bring it down to the proper (lower orbit) when close to the target. That's part of the performance reserve demanded of each launch (that is actually used).
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#31
by
douglas100
on 23 Mar, 2015 15:40
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Not if you are aiming for a specific slot in the plane.
Do they actually do that? If the satellite is injected into the correct plane can it not just drift to its operational spot during commissioning like a comsat in GSO?
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#32
by
jacqmans
on 24 Mar, 2015 20:20
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photo credit: Carleton Bailie
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#33
by
jacqmans
on 24 Mar, 2015 20:21
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ULA @ulalaunch
Are you ready for #GPSIIF9? The ULA Launch Readiness Review was completed this morning, and we are GO for launch on a #DeltaIV!
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#34
by
Galactic Penguin SST
on 25 Mar, 2015 06:36
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Moved for live coverage! 1st of 3 launches in 7 hours today!
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#35
by
Chris Bergin
on 25 Mar, 2015 11:19
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#36
by
jacqmans
on 25 Mar, 2015 11:58
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Vehicle: Delta IV GPS IIF-9
Issued: 25 March 2015 / 1200Z (0800 EDT)
Valid: 25 March 2015 / 1836 – 1854Z (1436 – 1454 EDT)
Synoptic Discussion: A strong low-level inversion is prevalent over Cape Canaveral causing morning fog. Visibility is down to less than ½ statute miles, but this fog will burn off between 1100L and 1200L. The high pressure area moving off the U.S. East Coast will cause winds to gradually veer and be from the east-northeast, but gusty winds are now forecast to hold off until Thursday. Showers are occurring along a convergent band 70 nautical miles to the southeast, but these will not be a concern for launch. High clouds are streaming over the area, but are located above the -20C level and are not a concern for launch. With dry air in the mid-levels of the atmosphere, there is only a slight concern for cumulus clouds for launch and the forecast is decreased to just a 10% chance of violating weather constraints. The primary concern for launch is cumulus cloud development. Thursday, the high pressure area to the northeast moves off to the east as a low pressure system moves into the Eastern U.S. Wind flow will shift and be from the southeast, and additional moisture will migrate in from the south as well. Given these factors, there is an increased chance of afternoon showers and late afternoon thunderstorms. Mid-level clouds will also be more prevalent, causing concern for thick cloud layers above the freezing level. Due to this additional concern, the probability of weather constraint violation for a 24-hour delay increased to 60%. The primary concerns for a 24-hour delay are flight through precipitation, cumulus clouds, and thick cloud layers.
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#37
by
Chris Bergin
on 25 Mar, 2015 12:06
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ULA: A few photos and a caption from tower rollback this morning. First motion was at 6:05 a.m. Today’s launch day forecast shows a 90 percent chance of favorable weather conditions for launch.
Cape Canaveral Air Force Station, Fla. (March 25, 2015) - A United Launch Alliance Delta IV rocket stands ready for launch at Space Launch Complex-37 with the GPS IIF-9 payload. Launch is scheduled for this afternoon at 2:36 p.m. EDT. GPS IIF-9 is the ninth in a series of next generation GPS satellites and will join a worldwide timing and navigation system utilizing 24 satellites in six different planes, with a minimum of four satellites per plane positioned in orbit approximately 11,000 miles above the Earth’s surface.
Photo: United Launch Alliance
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#38
by
ZachS09
on 25 Mar, 2015 12:34
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The foggy rollout reminds me of the August 2013 rollout of NROL-65.
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#39
by
averagespacejoe
on 25 Mar, 2015 14:03
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Has anyone seen the various patches for this mission? I know as long as MMS is next in line I won't see anything about this one on the ULA website.
they are not out yet. I get every patch and post it so there is no need to ask
You know Jim when I first asked this you were really snippy but now 4 hours before launch still no picture of the patch from you. So I guess there was a need to ask because you don't necessarily post it. Just had to get that off my chest. Go Delta IV! Go ULA! Go GPS IIF-9!
