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#920
by
FutureSpaceTourist
on 05 Apr, 2017 08:15
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Some clear shots of flames around the legs after touchdown in the landing video.
I know SES-10 is the heaviest F9 GTO launch to date with booster recovery, but how does it compare with JCSAT-16? I'm afraid I have no idea in terms of orbital parameters which launch required more dV?
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#921
by
Oersted
on 05 Apr, 2017 08:33
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Thanks for the link to the video. What I see in the video is a supremely confident landing by a mature system.
Amazing progress we have seen in the last year. Science and engineering rock!
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#922
by
Ben the Space Brit
on 05 Apr, 2017 09:50
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#923
by
sevenperforce
on 05 Apr, 2017 13:16
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Some clear shots of flames around the legs after touchdown in the landing video.
I know SES-10 is the heaviest F9 GTO launch to date with booster recovery, but how does it compare with JCSAT-16? I'm afraid I have no idea in terms of orbital parameters which launch required more dV?
JCSAT-16 massed 4.6 tonnes; SECO-2 was at 9,789 m/s at 208 km.
SES-10 massed 5.3 tonnes. Neither the hosted webcast nor the technical webcast showed the S2 velocity at SECO-2 -- perhaps because they knew it was going to fall short? -- but a glance at Heavens Above shows that the post-separation rocket body is currently floating in a 236x33,407 km orbit at an inclination of 26.2°.
If we know roughly the amount of impulse provided by the decoupler then a little bit of math should allow us to calculate the performance difference.
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#924
by
envy887
on 05 Apr, 2017 13:42
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Some clear shots of flames around the legs after touchdown in the landing video.
I know SES-10 is the heaviest F9 GTO launch to date with booster recovery, but how does it compare with JCSAT-16? I'm afraid I have no idea in terms of orbital parameters which launch required more dV?
JCSAT-16 massed 4.6 tonnes; SECO-2 was at 9,789 m/s at 208 km.
SES-10 massed 5.3 tonnes. Neither the hosted webcast nor the technical webcast showed the S2 velocity at SECO-2 -- perhaps because they knew it was going to fall short? -- but a glance at Heavens Above shows that the post-separation rocket body is currently floating in a 236x33,407 km orbit at an inclination of 26.2°.
If we know roughly the amount of impulse provided by the decoupler then a little bit of math should allow us to calculate the performance difference.
The sat and stage drift apart fairly slowly in the video after separation, and they mass about equally. So separation can't add more than maybe 5 m/s to the velocity.
However, depressurizing the stage tanks could slow it down slightly after separation. The difference between the stage orbit and the sat orbit when first observed was only ~35 m/s
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#925
by
edkyle99
on 05 Apr, 2017 15:32
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Here's a list of the six most recent Falcon 9 GTO missions, showing first track for the second stage and payload. I've added my rough, often inaccurate, guesses for delta-v difference. All of these had or attempted first stage landings downrange except for Echostar 23, which was an expendable flight. The JCSAT 16 stage reentered after a month after appearing to have lowered its orbit post-separation on launch day. It weighed 0.7 tonnes less than SES 10.
Payload Stage 2 Orbit Payload Orbit Mass Delta-v
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JCSAT 14 181 x 35869 km x 23.7 189 x 35957 km x 23.7 4.7 t 3 m/s
Thaicom 8 384 x 89872 km x 23.7 350 x 90226 km x 21.2 3.03 t 4 m/s
Eutelsat 117WB 402 x 62603 km x 21.2 395 x 62591 km x 24.7 4.15 t 3 m/s
JCSAT 16 74 x 34400 km x 20.9 181 x 35898 km x 20.9 4.6 t 69 m/s
Echosat 23 179 x 35775 km x 22.5 179 x 35903 km x 22.4 5.6 t 2 m/s
SES 10 217 x 33395 km x 26.3 247 x 35673 km x 26.2 5.3 t 39 ms
----------------------------------------------------------------------------------
- Ed Kyle
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#926
by
pb2000
on 05 Apr, 2017 16:21
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It's looking probable that SES sacrificed a bit of spacecraft lifetime in order to be part of a historical event. Considering the savings of a normal Falcon 9 + the reuse discount, I'm sure SES is still making out like bandits vs an Atlas/Proton/Ariane mission.
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#927
by
larmeyers
on 05 Apr, 2017 16:22
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I've probably just missed this, and please remove if not L2-worthy, but is it known if SES 10 had the same engines that flew with 1021 on her first flight?
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#928
by
Hauerg
on 05 Apr, 2017 16:26
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Same engines iirc..
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#929
by
cscott
on 05 Apr, 2017 16:40
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SES-10 massed 5.3 tonnes. Neither the hosted webcast nor the technical webcast showed the S2 velocity at SECO-2 -- perhaps because they knew it was going to fall short? -- but a glance at Heavens Above shows that the post-separation rocket body is currently floating in a 236x33,407 km orbit at an inclination of 26.2°.
It didn't "fall short." We have direct word on that in L2.
It may be that this was a "burn to depletion" mission, however, and so final SECO velocity was considered sensitive.
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#930
by
cscott
on 05 Apr, 2017 16:49
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I've probably just missed this, and please remove if not L2-worthy, but is it known if SES 10 had the same engines that flew with 1021 on her first flight?
Yes, same engines. This was in the public presser.
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#931
by
ugordan
on 05 Apr, 2017 17:01
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It may be that this was a "burn to depletion" mission, however, and so final SECO velocity was considered sensitive.
The orbital parameters provided by Martin Halliwell prior to the launch seem oddly specific and precise for a minimum-residual-type shutdown profile. 6:15 into this video
It didn't "fall short." We have direct word on that in L2.
From a SpaceX person at that. Maybe it didn't "fall short". Or maybe it did "fall short" of the target orbit stated above, but still ended up within *contractual* requirements. 50 shades of "fall short"?
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#932
by
getitdoneinspace
on 05 Apr, 2017 17:05
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https://www.shelby.senate.gov/public/index.cfm/mobile/newsreleases?ID=25F3AD2E-802A-23AD-4960-F512B9E205D2
Thank you for sharing this link. Amazing how wrong Shelby was in his prediction of the future for commercial space. This news release should be read by all his constituents. He was wrong on most every single point. Furthermore, his statement of facts known at the time were twisted and presented in inaccurate context. Hopefully as time unfolds and he continues to be against the right direction, his influence will diminish and perhaps disappear.
I have two observations from this historic moment. 1) Don't underestimate the power of the entrepreneurial spirit. The attributes of this spirit is a drive and persistence to overcome obstacles rather than "cancel the program". Also, there is a laser focus on achieving the results rather than a focus on a specific/unchanging means to try and reach those results (Shelby's blind support for Constellation/SLS). 2) Don't solicit the view of ONLY the old guys is a field that must advance far and fast (Congressional testimony generally has only been solicited from old timers in the space field). I am an old mainframe guy. In a hearing on system modernization I could offer some perspective, but it should be balanced or even heavily weighted toward the younger experts in the field since it is more their future than mine.
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#933
by
JasonAW3
on 05 Apr, 2017 18:03
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#934
by
BabaORileyUSA
on 05 Apr, 2017 18:03
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Here's a list of the six most recent Falcon 9 GTO missions, showing first track for the second stage and payload. I've added my rough, often inaccurate, guesses for delta-v difference. All of these had or attempted first stage landings downrange except for Echostar 23, which was an expendable flight. The JCSAT 16 stage reentered after a month after appearing to have lowered its orbit post-separation on launch day. It weighed 0.7 tonnes less than SES 10.
Payload Stage 2 Orbit Payload Orbit Mass Delta-v
----------------------------------------------------------------------------------
JCSAT 14 181 x 35869 km x 23.7 189 x 35957 km x 23.7 4.7 t 3 m/s
Thaicom 8 384 x 89872 km x 23.7 350 x 90226 km x 21.2 3.03 t 4 m/s
Eutelsat 117WB 402 x 62603 km x 21.2 395 x 62591 km x 24.7 4.15 t 3 m/s
JCSAT 16 74 x 34400 km x 20.9 181 x 35898 km x 20.9 4.6 t 69 m/s
Echosat 23 179 x 35775 km x 22.5 179 x 35903 km x 22.4 5.6 t 2 m/s
SES 10 217 x 33395 km x 26.3 247 x 35673 km x 26.2 5.3 t 39 ms
----------------------------------------------------------------------------------
- Ed Kyle
The values you are showing for the SES-10 are after a velocity augmentation maneuver. The apogee height of Elset One was 33,460 km, about 1,200 km lower than what you are showing.
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#935
by
edkyle99
on 05 Apr, 2017 18:57
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The values you are showing for the SES-10 are after a velocity augmentation maneuver. The apogee height of Elset One was 33,460 km, about 1,200 km lower than what you are showing.
I'm using the oldest TLE listed at Space-Track, Epoch Fri Mar 31 2017 13:57:30 GMT, 14 or 15 hours after launch so time enough for one complete orbit.
- Ed Kyle
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#936
by
envy887
on 05 Apr, 2017 19:06
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The values you are showing for the SES-10 are after a velocity augmentation maneuver. The apogee height of Elset One was 33,460 km, about 1,200 km lower than what you are showing.
I'm using the oldest TLE listed at Space-Track, Epoch Fri Mar 31 2017 13:57:30 GMT, 14 or 15 hours after launch so time enough for one complete orbit.
- Ed Kyle
Isn't it odd that the stage is now at a 240 km perigee, over 20 km higher than the first TLE?
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#937
by
spacenut
on 05 Apr, 2017 19:29
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I voted for Shelby, but for a lot of other issues. Shelby has been around for a LONG time. I think he was in office when Shuttle began. So, I think he is under the impression that Constellation and SLS are truely "Shuttle derived". SLS really is a whole new rocket. Engines different and on the bottom and not side mounted. Even the solids are different, not the standard 4 segments. He is also a lawyer and politician, not a rocket scientist. He just wants jobs in North Alabama. He is getting old, and I think he needs to step down after this term, and let someone younger take his place. Don't know what that would do to NASA.
Anyway, is this booster going to be used again? Maybe for a LEO flight to ISS?
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#938
by
ChrisGebhardt
on 05 Apr, 2017 19:58
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#939
by
jcm
on 05 Apr, 2017 20:01
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The values you are showing for the SES-10 are after a velocity augmentation maneuver. The apogee height of Elset One was 33,460 km, about 1,200 km lower than what you are showing.
I'm using the oldest TLE listed at Space-Track, Epoch Fri Mar 31 2017 13:57:30 GMT, 14 or 15 hours after launch so time enough for one complete orbit.
- Ed Kyle
Isn't it odd that the stage is now at a 240 km perigee, over 20 km higher than the first TLE?
The Stage 2 has the lower apogee height, but the earliest elset for the payload has the higher one.
Yes, it's possible there was a PVA burn, but much more likely there was a Stage 2 CCAM/depletion burn which lowered its apogee from an initial one that was the same as the payload. Unless you have evidence beyond the TLEs, I'd say there's not reason to imagine that the launch undershot.
I'll note that the difference between the first and second elsets for Stage 2 (the 18 km higher perigee
and a 0.13 deg inclination change) could just be a bad fit for the first elset based on limited data, or
else residual venting of some kind.
