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#200
by
mark_m
on 05 Mar, 2017 18:01
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Iridium is launched into 86.6 degrees, 625km circular orbit. Formosat-5 is 97.4 degrees, 720km circular. The application for the SpaceX test sats says deployment at 97.44 degrees, 514-km circular orbit (they could always file an amendment to change that). I don't know what the orbits for SSO-A or SAOCOM-1A are going to be?
If a polar orbit is inclined 90 degrees, what does it mean for an orbit to be inclined 97.4 degrees? Isn't that just the same as one inclined 82.6 degrees?
If I'm thinking about it correctly, 82.6º would be almost polar, but the component that's not polar is in the same direction as the rotation of the Earth, whereas 97.4º is slightly retrograde. Both would be 7.4º away from exactly polar.
-82.6º would be in the same plane as 97.4º, but traveling in the opposite direction.
Edit: Changed after a reread made me think my first answer didn't make sense.
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#201
by
WHAP
on 05 Mar, 2017 19:00
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OK but one can argue that it is really the pad that took time, that was the bottleneck. There is evidence 39A needed and still needs more work than nominal, while SLC4 is idle, why not launch as much as possible from what has been accumulated on the West coast?
I know SpaceX has reasons for this. I would genuinely like to understand the answer.
My guess is that second stages are a bottleneck. Both failures in the last 2 years were do 2nd stage issues. I doubt SpaceX restarted building 2nd stages until quite late in the Amos-6 investigation.
Another piece of the story I think is that towards the end of March, ULA won't launch from the Cape for about 3 months. I think you are going to see SpaceX try and pack in as many launches as possible in those 3 months.
Sorry, but what difference does ULA launching from the Cape make? If you assume each vehicle takes 3 days on the Range, including a WDR and two attempts (typically no WDR and one attempt), that's a total of 6 days in March. Please don't try to suggest that this reduction in availability is what's hampering SpaceX from clearing its backlog. There are ample opportunities for SpaceX to get off the ground with the remaining 80% of days in March.
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#202
by
Herb Schaltegger
on 05 Mar, 2017 22:54
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Iridium is launched into 86.6 degrees, 625km circular orbit. Formosat-5 is 97.4 degrees, 720km circular. The application for the SpaceX test sats says deployment at 97.44 degrees, 514-km circular orbit (they could always file an amendment to change that). I don't know what the orbits for SSO-A or SAOCOM-1A are going to be?
If a polar orbit is inclined 90 degrees, what does it mean for an orbit to be inclined 97.4 degrees? Isn't that just the same as one inclined 82.6 degrees?
No. An orbit with an inclination of less than 90 degrees has a small eastward component. An orbit with an inclination greater than 90 degrees is at least partially retrograde.
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#203
by
Wolfram66
on 05 Mar, 2017 23:18
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Iridium is launched into 86.6 degrees, 625km circular orbit. Formosat-5 is 97.4 degrees, 720km circular. The application for the SpaceX test sats says deployment at 97.44 degrees, 514-km circular orbit (they could always file an amendment to change that). I don't know what the orbits for SSO-A or SAOCOM-1A are going to be?
If a polar orbit is inclined 90 degrees, what does it mean for an orbit to be inclined 97.4 degrees? Isn't that just the same as one inclined 82.6 degrees?
No. An orbit with an inclination of less than 90 degrees has a small eastward component. An orbit with an inclination greater than 90 degrees is at least partially retrograde.
97.4 is more indicative of a SSO or Sun-Synchronous Orbit ... hence the name SSO-A
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#204
by
Herb Schaltegger
on 05 Mar, 2017 23:23
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Iridium is launched into 86.6 degrees, 625km circular orbit. Formosat-5 is 97.4 degrees, 720km circular. The application for the SpaceX test sats says deployment at 97.44 degrees, 514-km circular orbit (they could always file an amendment to change that). I don't know what the orbits for SSO-A or SAOCOM-1A are going to be?
If a polar orbit is inclined 90 degrees, what does it mean for an orbit to be inclined 97.4 degrees? Isn't that just the same as one inclined 82.6 degrees?
No. An orbit with an inclination of less than 90 degrees has a small eastward component. An orbit with an inclination greater than 90 degrees is at least partially retrograde.
97.4 is more indicative of a SSO or Sun-Synchronous Orbit ... hence the name SSO-A
Now think through how an orbit can be sun-synchronous as the Earth rotates ...
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#205
by
meberbs
on 06 Mar, 2017 00:02
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Iridium is launched into 86.6 degrees, 625km circular orbit. Formosat-5 is 97.4 degrees, 720km circular. The application for the SpaceX test sats says deployment at 97.44 degrees, 514-km circular orbit (they could always file an amendment to change that). I don't know what the orbits for SSO-A or SAOCOM-1A are going to be?
If a polar orbit is inclined 90 degrees, what does it mean for an orbit to be inclined 97.4 degrees? Isn't that just the same as one inclined 82.6 degrees?
No. An orbit with an inclination of less than 90 degrees has a small eastward component. An orbit with an inclination greater than 90 degrees is at least partially retrograde.
97.4 is more indicative of a SSO or Sun-Synchronous Orbit ... hence the name SSO-A
Now think through how an orbit can be sun-synchronous as the Earth rotates ...
Sun synchronous means the orbit precesses once per year, and is only possible because of the J2 perturbation. While prograde vs retrograde changes the direction of the precession, it is not exactly intuitive which direction leads to which precession.
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#206
by
Herb Schaltegger
on 06 Mar, 2017 00:12
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Iridium is launched into 86.6 degrees, 625km circular orbit. Formosat-5 is 97.4 degrees, 720km circular. The application for the SpaceX test sats says deployment at 97.44 degrees, 514-km circular orbit (they could always file an amendment to change that). I don't know what the orbits for SSO-A or SAOCOM-1A are going to be?
If a polar orbit is inclined 90 degrees, what does it mean for an orbit to be inclined 97.4 degrees? Isn't that just the same as one inclined 82.6 degrees?
No. An orbit with an inclination of less than 90 degrees has a small eastward component. An orbit with an inclination greater than 90 degrees is at least partially retrograde.
97.4 is more indicative of a SSO or Sun-Synchronous Orbit ... hence the name SSO-A
Now think through how an orbit can be sun-synchronous as the Earth rotates ...
Sun synchronous means the orbit precesses once per year, and is only possible because of the J2 perturbation. While prograde vs retrograde changes the direction of the precession, it is not exactly intuitive which direction leads to which precession.
Setting aside the technical details of a sun-synchronous orbit, an orbit with an inclination of greater than 90 degrees is - by definition - retrotrograde. Which is what I said above. In practice, typical sun synchronous orbits are generally >90 degrees, and thus retrograde.
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#207
by
FutureSpaceTourist
on 06 Mar, 2017 06:35
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Jeff Foust's write-up of Spaceflight's rebooking launches:
http://spacenews.com/spacex-delays-force-spaceflight-to-find-alternative-launches/It contains this:
Spaceflight spokeswoman Jodi Sorensen said March 2 that most of the satellites that had been flying on Sherpa will be rebooked on one of two launches. One is on the company’s own dedicated Falcon 9 mission, dubbed SSO-A, scheduled to launch from Vandenberg later this year. The other is an unspecified “international launch” scheduled for this summer or fall.
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#208
by
mtakala24
on 06 Mar, 2017 13:46
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#209
by
Jarnis
on 06 Mar, 2017 13:54
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Jeff Foust's write-up of Spaceflight's rebooking launches:
http://spacenews.com/spacex-delays-force-spaceflight-to-find-alternative-launches/
It contains this:
Spaceflight spokeswoman Jodi Sorensen said March 2 that most of the satellites that had been flying on Sherpa will be rebooked on one of two launches. One is on the company’s own dedicated Falcon 9 mission, dubbed SSO-A, scheduled to launch from Vandenberg later this year. The other is an unspecified “international launch” scheduled for this summer or fall.
So is the delay with the primary payload, or with the rocket? Or is this some kind of deal where different launches have different contractual terms and Formosat-5 was kinda "we'll launch it whenever we feel like" while later-booked SSO-A has a more firm launch date in the contract?
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#210
by
gongora
on 06 Mar, 2017 14:18
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So is the delay with the primary payload, or with the rocket? Or is this some kind of deal where different launches have different contractual terms and Formosat-5 was kinda "we'll launch it whenever we feel like" while later-booked SSO-A has a more firm launch date in the contract?
There seem to have been various reasons for delays over the past couple years, but the last few months the delay was definitely on the rocket side. More than half of the payloads that were going to be on SHERPA have ALREADY LAUNCHED on PSLV. Once that happened the odds of the SHERPA getting canceled from this flight were pretty high.
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#211
by
FutureSpaceTourist
on 06 Mar, 2017 15:22
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#212
by
SmallKing
on 01 May, 2017 00:58
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#213
by
rockets4life97
on 01 May, 2017 01:08
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#214
by
wannamoonbase
on 30 May, 2017 16:18
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3 Questions as this long awaiting flight nears:
1) Any word on whether this is going to attempt RTLS
2) If SpaceX has permission to return to VAFB
3) Will the Landing Zone will be ready for this launch?
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#215
by
AncientU
on 20 Jun, 2017 19:31
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New article:
Formosat-5 launch imminent
Taiwan is expecting to receive SpaceX’s confirmation for the launch date imminently because according to SpaceX’s schedule, Formosat-5 must be shipped to the US at least 40 days prior to its lift-off, another source said.
When asked for comment, NARL refused to confirm or deny the launch date, but said it will inform the public via the proper channels once it receives official notification from SpaceX.
The satellite is second on SpaceX’s launch schedule from Vandenberg Air Force Base in California, after its launch later this month of Iridium NEXT satellites for Iridium Communications Inc.
Under the terms of its contract, SpaceX is allowed a six-month grace period for delays, after which it is obliged to pay 1.25 percent of the contract for each month of delays up to a maximum of eight months.
SpaceX’s six-month grace period finished in August last year.
http://www.taipeitimes.com/News/taiwan/archives/2017/06/21/2003672985
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#216
by
gongora
on 20 Jun, 2017 19:38
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Another quote from the article linked above:
After lifting the halt on missions this year, SpaceX informed the National Applied Research Laboratories (NARL) that Formosat-5 would launch in late August, and Taiwan should begin preparations, a source familiar with the project said.
edit: if this was a Falcon 1 launch contract I doubt SpaceX is very concerned about the monthly penalty.
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#217
by
AncientU
on 20 Jun, 2017 20:12
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Wouldn't this be an excellent flight for SpaceX to launch one or more of its DemoSats?
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#218
by
gongora
on 20 Jun, 2017 20:46
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Wouldn't this be an excellent flight for SpaceX to launch one or more of its DemoSats?
Not sure they're ready yet. When they said they're launching one by the end of the year I assumed that meant NET December
Is there room for one SpaceX sat on the top of the Iridium stack?
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#219
by
ChrisGebhardt
on 26 Jun, 2017 00:00
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Another quote from the article linked above:
After lifting the halt on missions this year, SpaceX informed the National Applied Research Laboratories (NARL) that Formosat-5 would launch in late August, and Taiwan should begin preparations, a source familiar with the project said.
edit: if this was a Falcon 1 launch contract I doubt SpaceX is very concerned about the monthly penalty.
I'd take "late-August" with a huge grain of salt. Today there was a lot of "July" talk for this. And Iridium has the late August slot for Iridium 21-30 on 24 August (and all of those satellites -- including the batch for 31-40 -- are all ready to go).
So this really doesn't sound right at this point for Formosat 5 in "late August."
Now, of course, this could all change. So just writing this as a word of caution.
Is there room for one SpaceX sat on the top of the Iridium stack?