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#920
by
Kabloona
on 09 Jan, 2018 14:32
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Indeed.
There is a probable sighting of S2 over Sudan approx 2:15 after launch, which seems to fit with it having crossed the Atlantic twice and the Pacific once - and being on the way to a de-orbit burn into the Pacific.
*If* Zuma was still attached to the S2 (and presumably there would be some way of knowing that), then is there really not a contingency whereby the stage can be commanded not to undertake its de-orbit burn pending resolution of the non-separated satellite?
And *if* that was the case, surely the 'rumours' would have been a bit more clearly aligned that the satellite had not separated and a resolution was being attempted - ie leave the two attached until power / control was lost?
This is the best summary of the Sudan sighting I have seen:
http://www.satobs.org/seesat/Jan-2018/0074.html
My WAG based on the above is that the Northrop Grumman-supplied payload adapter failed to separate the spacecraft, and the order was given to deorbit the second stage with the payload attached while it still had the power to do so. The spacecraft, even if operational, almost certainly would not have been able to complete its mission with a second stage attached to it so they would have no other choice but to ditch the whole kit and kaboodle.
In case someone doesn't click through to the second link, this is the one that describes the Sudan sighting:
https://sattrackcam.blogspot.nl/2018/01/fuel-dump-of-zumas-falcon-9-upper-stage.html
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#921
by
douglas100
on 09 Jan, 2018 14:35
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The second stage would send a release signal to the payload adapter after reaching the target orbit. Would there be a handshake with a deployed signal coming back to enable the deorbit sequence?
I would expect it to work that way.
I doubt that. It's been stated many times, and by SpaceX themselves, that the F9 acts autonomously. The de-orbit sequence would operate whether the payload separated or not. There's no reason for an external signal to trigger the de-orbit. If the payload fails to separate then it's automatically LOM and what happens afterwards doesn't matter.
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#922
by
kevin-rf
on 09 Jan, 2018 14:37
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Change the word "Atlantic" and the report is plausible. Not surprising that a minor (!) error would creep into a report written by (or sourced from) someone probably not an expert on the subject.
Indeed.
There is a probable sighting of S2 over Sudan approx 2:15 after launch, which seems to fit with it having crossed the Atlantic twice and the Pacific once - and being on the way to a de-orbit burn into the Pacific.
*If* Zuma was still attached to the S2 (and presumably there would be some way of knowing that), then is there really not a contingency whereby the stage can be commanded not to undertake its de-orbit burn pending resolution of the non-separated satellite?
And *if* that was the case, surely the 'rumours' would have been a bit more clearly aligned that the satellite had not separated and a resolution was being attempted - ie leave the two attached until power / control was lost?
Having witnessed a few Centaur blow down events, (the east coast NOSS launches, MMS) The satellite if separated will be visible, especially if you train a good pair of binoculars (or larger optics on it). Depending on the quality of the images coming out of Sudan, you might be able to inspect them and find Zuma. Though, I am not holding out much hope.
Interesting quote from Marco on his blog post;
The sighting points to a somewhat higher orbital altitude for Zuma than I had anticipated before the launch: with hindsight, I had too much of an idée-fixe that the orbital altitude would be similar to that of USA 276. The Falcon 9 sighting over East Africa suggests an altitude over double as high, in the order of 900-1000 km rather than my original 400 km estimate.
https://sattrackcam.blogspot.nl/2018/01/fuel-dump-of-zumas-falcon-9-upper-stage.html(my money is still on decoy)
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#923
by
cscott
on 09 Jan, 2018 14:38
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So, just throwing this out there: What if the speculation about a hypersonic re-entry test vehicle is true? If so, then the 'LEO target orbit' was misinformation and everything went as planned.
Zuma separated nominally after the upper stage completed putting it on its suborbital trajectory towards the Pacific Test Range (hence the independently-measured shorter-than-normal upper stage burn).
The Sudan sighting proves the upper stage made it to orbit (not a suborbital trajectory). In order for it to have been seen there at that time it needed to have done an orbit and a half around the earth.
Wrt hypersonic tests and the west coast: if you're launching in a suborbital trajectory you need a large amount of clear space for your vehicle to fly over, since it could (in theory) come down anywhere along that path if things go south. There's a lot more clear space on the Pacific ocean side ... and we happen to have good tracking radars all along that side too because of who's on the other side of that ocean.
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#924
by
Ben the Space Brit
on 09 Jan, 2018 14:40
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The second stage would send a release signal to the payload adapter after reaching the target orbit. Would there be a handshake with a deployed signal coming back to enable the deorbit sequence?
I would expect it to work that way.
As I understand it, most payload interfaces have a small thin-gauge electrical wire connecting the launch vehicle to the spacecraft. When the payload separates, the wire snaps, causing the circuit to break, informing the LV that the payload has been deployed. However, there have been one or two cases where, due to processing errors, the payload is hard-connected to the interface, the wire breaks and the spacecraft just dangles on the end of the deployed separation structure but still secured to it by tags, clips or bolts that should have been removed before encapsulation.
This scenario is very rare but it
is possible; it only takes one error to go undetected during the payload processing phase.
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#925
by
Kabloona
on 09 Jan, 2018 14:41
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Change the word "Atlantic" and the report is plausible. Not surprising that a minor (!) error would creep into a report written by (or sourced from) someone probably not an expert on the subject.
Indeed.
There is a probable sighting of S2 over Sudan approx 2:15 after launch, which seems to fit with it having crossed the Atlantic twice and the Pacific once - and being on the way to a de-orbit burn into the Pacific.
*If* Zuma was still attached to the S2 (and presumably there would be some way of knowing that), then is there really not a contingency whereby the stage can be commanded not to undertake its de-orbit burn pending resolution of the non-separated satellite?
And *if* that was the case, surely the 'rumours' would have been a bit more clearly aligned that the satellite had not separated and a resolution was being attempted - ie leave the two attached until power / control was lost?
Having witnessed a few Centaur blow down events, (the east coast NOSS launches, MMS) The satellite if separated will be visible...
I think you meant "The satellite if
not separated will be visible..."
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#926
by
Jim
on 09 Jan, 2018 14:42
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How many times does this have to be stated?
Launch vehicles do not receive commands after launch
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#927
by
Jester
on 09 Jan, 2018 14:45
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How many times does this have to be stated?
Launch vehicles do not receive commands after launch
if nominal ;-)
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#928
by
cscott
on 09 Jan, 2018 14:47
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Wait a second here, how does such a lightweight payload cost over $1 Billion if it is just a satellite?
? This was a light payload and 1st stage boostback return was possible.
In informal scaremongering of this sort, it's common to include all r&d costs onto the quoted figure. So it could cost significantly less than $1B to make a replacement flight vehicle, but if you add up all of the program costs to date, includng previous tests, all staff salaries, etc, you get $1B.
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#929
by
Kabloona
on 09 Jan, 2018 14:49
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Wait a second here, how does such a lightweight payload cost over $1 Billion if it is just a satellite?? This was a light payload and 1st stage boostback return was possible.
In informal scaremongering of this sort, it's common to include all r&d costs onto the quoted figure. So it could cost significantly less than $1B to make a replacement flight vehicle, but if you add up all of the program costs to date, includng previous tests, all staff salaries, etc, you get $1B.
Not to mention that the "mission cost," including that of the launch vehicle, sometimes gets reported/interpreted incorrectly as "payload cost."
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#930
by
Rocket Science
on 09 Jan, 2018 14:57
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Lots of speculation that zuma was a satellite that failed and reentered around the same time as S2.
I'll add to the noise in a different direction by speculating that Zuma was a hypersonic vehicle, and that it functioned as planned.
Northrup Grumman has been in the hypersonic vehicle business for a long time, and indeed, they are hiring for hypersonic vehicle design engineers in Melbourne right now (check their HR site).
Just last spring, I saw one of their hypersonic cruise missile program trailers parked at a Busy Bee gas station on the way to the Cape with several security vehicle escorts. When I saw it, I giggled to myself that their super secret program had its damn logo emblazoned all over the side of the trailer.
So, unless Zuma was really a satellite, everything else- including why no agency will own up to the launch- fits nicely with it being a vehicle test for NG.
such a payload would have been tested on the west coast like the other similar vehicles
We don't know enough to state that.
Wrong, we know enough that hypersonic vehicles are better tested from the west coast.
Sure, if you want to advertise that it's a hypersonic vehicle test....
There are no facilities on the east coast to support such tests. It went northernly, no radars, imaging or test sensors.
And it went into orbit, hence not a hypersonic test.
Question Jim, what if this was an orbital entry test and not just a hypersonic atmospheric test. The X-23 PRIME although launched from Vandy and the vehicle was accelerated to a sub-orbital entry velocity over the pacific. Would not 1-2 1/2 revs and then end over the west coast be not possible with assets there as mentioned. The X-23 Prime did not need conditioned air for flight under it's faring as far as I can recall. ASSET was similar in testing...
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#931
by
Zach Swena
on 09 Jan, 2018 15:28
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What about a stealth sat test? I know it is a bit of a long shot, but if they did figure out a way to hind a bird from tracking, this would be how the PR would be handled...
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#932
by
JonathanD
on 09 Jan, 2018 15:33
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What about a stealth sat test? I know it is a bit of a long shot, but if they did figure out a way to hind a bird from tracking, this would be how the PR would be handled...
You are giving them too much credit imho. They could have just clammed up about it like they would any NROL launch and that would be it. It's interesting that members of Congress have been briefed, certainly deepens the intrigue of who this belonged to.
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#933
by
ArbitraryConstant
on 09 Jan, 2018 15:36
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The speculation is getting ridiculous.
The customer values their privacy and as far as I'm concerned they are welcome to it.
And whatever SpaceX is or isn't allowed to say, the communication that matters is no stand down.
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#934
by
Rocket Science
on 09 Jan, 2018 15:51
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The speculation is getting ridiculous.
The customer values their privacy and as far as I'm concerned they are welcome to it.
And whatever SpaceX is or isn't allowed to say, the communication that matters is no stand down.
Speculation keeps the kids from going out and playing on the road...
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#935
by
meekGee
on 09 Jan, 2018 15:52
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Here are screen grabs of the fairing separation. Not that the vehicle is moving to the right from the perspective of the viewer. We can clearly see a fairing separate from the top. However, the bottom fairing appears as a bright blob right next to the exhaust. Not sure if this is due to the viewing angle.
The rocket is also moving "downwards" from the user perspective.
And the bright plume is the very large over-expanded vacuum plume...
I'm surprised the fairing is even visible at all.
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#936
by
wolfpack
on 09 Jan, 2018 15:59
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The second stage "knows" if the payload separated or not, true? Or is it "open loop" in that the sep command is sent and that's it? Breakwire status seems an easy thing to check.
What do launch vehicles do if S/C sep fails? Would S2 continue on as if nothing happened or would it inhibit the de-orbit sequence? I know F9 is a proprietary design, but lots of folks here know what other LV's would do.
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#937
by
Oli
on 09 Jan, 2018 16:02
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#938
by
Star One
on 09 Jan, 2018 16:02
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Wait a second here, how does such a lightweight payload cost over $1 Billion if it is just a satellite?? This was a light payload and 1st stage boostback return was possible.
In informal scaremongering of this sort, it's common to include all r&d costs onto the quoted figure. So it could cost significantly less than $1B to make a replacement flight vehicle, but if you add up all of the program costs to date, includng previous tests, all staff salaries, etc, you get $1B.
Not really that surprised with this kind of payload. Misty cost something like $9.5 billion with all the stealth adaptations that’s why it was a controversial program. If this has similar characteristics I could imagine even a relatively small payload seeing ballooning costs.
What about a stealth sat test? I know it is a bit of a long shot, but if they did figure out a way to hind a bird from tracking, this would be how the PR would be handled...
There Ain't No Stealth In Space.
http://www.projectrho.com/public_html/rocket/spacewardetect.php
Yes there is.
https://en.m.wikipedia.org/wiki/Misty_(satellite)
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#939
by
NGCHunter
on 09 Jan, 2018 16:05
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Incredible footage of stage sep and the boostback burn.
Thanks! That was my video. I'm hoping at some point other launch regulars who do tracking shots start to adopt my setup and software for their shots as well. The software is very experimental, but it's freely available. Computer, joystick, and telescope not included, of course.
? This was a light payload and 1st stage boostback return was possible.