Author Topic: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION  (Read 234188 times)

Offline Skyrocket

  • Extreme Veteran
  • Senior Member
  • *****
  • Posts: 2082
  • Frankfurt am Main, Germany
  • Liked: 276
  • Likes Given: 69
Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #600 on: 05/04/2017 03:23 PM »
I'm guessing that attempting to 'stealth' a spacecraft with low-optical reflectivity material would be counter-productive as it would greatly increase the internal heating from sunlight.
A black satellite introduces no huge thermal problems.  It absorbs a lot of sunlight, but it's also a very good emitter, so it balances out.

Another approach is to cover the spacecraft with a mirror, or mirrors, that re-direct the line of sight from Earth into space.

These and other approaches are summarized in the A Stealth Satellite Sourcebook, an open summary of what is known or suspected about space stealth.

A black satellite will appear very bright in infra-red in front of the cold space, so this is not a good way for stealth. The known stealth satellite attempts (eg LES 8 ) appear to have used the mirror concept.
« Last Edit: 05/04/2017 03:24 PM by Skyrocket »

Offline LouScheffer

  • Full Member
  • ****
  • Posts: 1555
  • Liked: 1757
  • Likes Given: 199
Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #601 on: 05/04/2017 03:57 PM »
I'm guessing that attempting to 'stealth' a spacecraft with low-optical reflectivity material would be counter-productive as it would greatly increase the internal heating from sunlight.
A black satellite introduces no huge thermal problems.  It absorbs a lot of sunlight, but it's also a very good emitter, so it balances out.

Another approach is to cover the spacecraft with a mirror, or mirrors, that re-direct the line of sight from Earth into space.

These and other approaches are summarized in the A Stealth Satellite Sourcebook, an open summary of what is known or suspected about space stealth.

A black satellite will appear very bright in infra-red in front of the cold space, so this is not a good way for stealth. The known stealth satellite attempts (eg LES 8 ) appear to have used the mirror concept.
Researchers have used fancy materials to get radiative cooling during the daytime by enhancing the emissivity in atmospheric windows.  Perhaps for stealth you could do the opposite, making a material that radiates only in the wavelengths where the atmosphere is opaque.  This would allow it to cool while still being hard to spot from the ground.
« Last Edit: 05/04/2017 03:59 PM by LouScheffer »

Offline Lars-J

  • Senior Member
  • *****
  • Posts: 3470
  • California
  • Liked: 2700
  • Likes Given: 1729
Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #602 on: 05/04/2017 05:47 PM »
I'm guessing that attempting to 'stealth' a spacecraft with low-optical reflectivity material would be counter-productive as it would greatly increase the internal heating from sunlight.
A black satellite introduces no huge thermal problems.  It absorbs a lot of sunlight, but it's also a very good emitter, so it balances out.

Another approach is to cover the spacecraft with a mirror, or mirrors, that re-direct the line of sight from Earth into space.

These and other approaches are summarized in the A Stealth Satellite Sourcebook, an open summary of what is known or suspected about space stealth.

A black satellite will appear very bright in infra-red in front of the cold space, so this is not a good way for stealth. The known stealth satellite attempts (eg LES 8 ) appear to have used the mirror concept.
Researchers have used fancy materials to get radiative cooling during the daytime by enhancing the emissivity in atmospheric windows.  Perhaps for stealth you could do the opposite, making a material that radiates only in the wavelengths where the atmosphere is opaque.  This would allow it to cool while still being hard to spot from the ground.

Or you could use a simpler approach... Black earth facing side, and a high emmisive/radiating surface facing away from earth.

Offline gosnold

  • Full Member
  • ****
  • Posts: 414
  • Liked: 111
  • Likes Given: 892
Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #603 on: 05/04/2017 05:56 PM »
I'm guessing that attempting to 'stealth' a spacecraft with low-optical reflectivity material would be counter-productive as it would greatly increase the internal heating from sunlight.
A black satellite introduces no huge thermal problems.  It absorbs a lot of sunlight, but it's also a very good emitter, so it balances out.

Another approach is to cover the spacecraft with a mirror, or mirrors, that re-direct the line of sight from Earth into space.

These and other approaches are summarized in the A Stealth Satellite Sourcebook, an open summary of what is known or suspected about space stealth.

A black satellite will appear very bright in infra-red in front of the cold space, so this is not a good way for stealth. The known stealth satellite attempts (eg LES 8 ) appear to have used the mirror concept.
Researchers have used fancy materials to get radiative cooling during the daytime by enhancing the emissivity in atmospheric windows.  Perhaps for stealth you could do the opposite, making a material that radiates only in the wavelengths where the atmosphere is opaque.  This would allow it to cool while still being hard to spot from the ground.

Or you could use a simpler approach... Black earth facing side, and a high emmisive/radiating surface facing away from earth.

You could even have a black (in optical bands) and actively cooled Earth side, mirrors/faceted MLI on the side to reflect sunlight away from observers, and a radiator on the side opposite to the Earth.

Offline zubenelgenubi

  • Full Member
  • ****
  • Posts: 1181
  • Arc to Arcturus, then Spike to Spica
  • Commonwealth of Virginia
  • Liked: 251
  • Likes Given: 732
Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #604 on: 05/08/2017 03:50 PM »
One week after launch, and the amateur satellite observing community has not yet announced tracking USA 276.
(no slight to them)

It would be handy if there was a list of the intervals between launch and amateur identification for classified American/allied satellites launched in recent years.
Support your local planetarium!

Offline kevin-rf

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8526
  • Overlooking the path Mary's little Lamb took..
  • Liked: 1028
  • Likes Given: 235
Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #605 on: 05/08/2017 04:13 PM »
One week after launch, and the amateur satellite observing community has not yet announced tracking USA 276.
(no slight to them)

It would be handy if there was a list of the intervals between launch and amateur identification for classified American/allied satellites launched in recent years.
The amateur community tag most within a few days...

I suspect the nature of it's assumed initial orbit makes it difficult to track. As launched, it was launched in the morning to the ascending node. That means as launched the ground track for northern observers is during the day, while southern (below the equator) observers will currently see it at night. The 51 degree inclination also rules out active in South Africa ever getting a good view. It also makes it impossible for people north of London, and difficult but not impossible in Toronto. 

As predicted upthread, it will be a couple of weeks before the orbit should precess  enough for northern observers get a good crack at it.

We will most likely see an announcement on SeeSat as soon as it's found.
http://www.satobs.org/seesat/May-2017/index.html
If you're happy and you know it,
It's your med's!

Offline kevin-rf

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8526
  • Overlooking the path Mary's little Lamb took..
  • Liked: 1028
  • Likes Given: 235
Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #606 on: 05/10/2017 02:49 PM »
Interesting low possibility being floated by Ted Molczan on an unidentified seen Monday by Ron Coursen in the general vicinity of ISS. In bold is the last part where he is far from convinced this is USA 276.

http://www.satobs.org/seesat/May-2017/0040.html

Quote
From: Ted Molczan via Seesat-l <seesat-l_at_satobs.org>
Date: Tue, 9 May 2017 17:29:25 -0400
Ron asked:

> Did anyone figure out what the unidentified object was trailing along with
> ISS I observed on Monday Morning?

Several of us have been discussing your mystery object off-list, aided by the additional information that you provided.
I caution that the following is very preliminary and could prove to be without merit.

It does not appear to be any object that we know. NROL-76 launched into a plane that was in the vicinity of ISS. It
probably did not target the orbit of ISS, but as Cees Bassa pointed out, since ISS is a popular target, its close
proximity to that orbit could result in serendipitous sightings.

If your mystery object is related to NROL-76, then its plane is quite a bit west of where it would have been expected,
based on the circumstances of the launch. I have been experimenting with various orbits that could fit your sighting and
correlate with NROL-76.

Something around 48 deg inclination seems to fit. To align with the RAAN of ISS would have required a large manoeuvre
near the northern or southern apex of the orbit, which appears to be within the capability of the launch vehicle, with a
substantial payload. Interestingly, the resulting orbit would have roughly matched the plane of the stage 2 de-orbit
trajectory, implied by the time, location and orientation of the NOTAM co-ordinates.

Below are a few approximate orbits that closely approximate your sighting:

                                                         328 X 335 km
1 74401U          17128.36666670  .00000000  00000-0  00000-0 0    08
2 74401  48.0000 230.8000 0005000 209.7698 205.8000 15.80000000    08
                                                         357 X 363 km
1 74402U          17128.36666669  .00000000  00000-0  00000-0 0    07
2 74402  48.0000 231.2000 0005000 209.7698 205.4000 15.70000000    09
                                                         412 X 418 km
1 74403U          17128.36666668  .00000000  00000-0  00000-0 0    07
2 74403  48.0000 231.9700 0005000 209.7698 204.3674 15.50980000    04

The 74401 orbit would have been near eclipse at the time of your sighting, so it is the approximate lower bound of
altitude.

I am far from confident that your mystery object is related to NROL-76, but it seems a possibility.

Ted Molczan

If you're happy and you know it,
It's your med's!

Offline kevin-rf

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8526
  • Overlooking the path Mary's little Lamb took..
  • Liked: 1028
  • Likes Given: 235
Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #607 on: 05/24/2017 02:14 PM »
Since Star One asked on the updates thread and immediately got thumped.

Here is Ted Molczan's TLE from Leo Barhorst's  data. Star One, go up one post and you can compare the search TLE's with the current rough TLE.

http://www.satobs.org/seesat/May-2017/0112.html

Quote
The following elements are derived from Leo Barhorst's observations of early 2017 May 24 UTC:

USA 276                                                  398 X 401 km
1 42689U 17022A   17144.06548369  .00000000  00000-0  00000-0 0    02
2 42689  49.9572 164.5366 0001907 186.7642 173.3300 15.56136012    06
Arc 20170524.02-0524.08 WRMS resid 0.044 totl 0.009 xtrk

The arc is short, so this solution is approximate, but it should be adequate to reacquire the object tonight and
tomorrow.

Ted Molczan
If you're happy and you know it,
It's your med's!

Offline edkyle99

  • Expert
  • Senior Member
  • *****
  • Posts: 12849
    • Space Launch Report
  • Liked: 3607
  • Likes Given: 617
Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #608 on: 05/24/2017 02:14 PM »
400 km x 50 deg reported on the SeeSat group. 
http://satobs.org/seesat/May-2017/0108.html
https://twitter.com/planet4589/status/867225945727434752
Seems likely to be technology demonstration.  50 deg inclination misses most of Russia, for example, so not a typical NRO observation type orbit.

 - Ed Kyle 
« Last Edit: 05/24/2017 02:17 PM by edkyle99 »

Offline kevin-rf

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8526
  • Overlooking the path Mary's little Lamb took..
  • Liked: 1028
  • Likes Given: 235
Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #609 on: 05/24/2017 02:47 PM »
50 degrees does cover all of the mid east, North Korea, and China.
 
Actually with the exception of Canada, Most of Russia, Northern Europe, and a bit of Southern Chile/Argentina it pretty much covers the entire world. In some cases, when the orbital mechanics work out, you might get two visits a day.
If you're happy and you know it,
It's your med's!

Offline Star One

  • Senior Member
  • *****
  • Posts: 8260
  • UK
  • Liked: 1338
  • Likes Given: 168
Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #610 on: 05/24/2017 02:59 PM »
Since Star One asked on the updates thread and immediately got thumped.

Here is Ted Molczan's TLE from Leo Barhorst's  data. Star One, go up one post and you can compare the search TLE's with the current rough TLE.

http://www.satobs.org/seesat/May-2017/0112.html

Quote
The following elements are derived from Leo Barhorst's observations of early 2017 May 24 UTC:

USA 276                                                  398 X 401 km
1 42689U 17022A   17144.06548369  .00000000  00000-0  00000-0 0    02
2 42689  49.9572 164.5366 0001907 186.7642 173.3300 15.56136012    06
Arc 20170524.02-0524.08 WRMS resid 0.044 totl 0.009 xtrk

The arc is short, so this solution is approximate, but it should be adequate to reacquire the object tonight and
tomorrow.

Ted Molczan
Thank you for that's most helpful. Sounds more optical reconnaissance than radar in that kind of orbit.
« Last Edit: 05/24/2017 03:01 PM by Star One »

Offline kevin-rf

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8526
  • Overlooking the path Mary's little Lamb took..
  • Liked: 1028
  • Likes Given: 235
Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #611 on: 05/24/2017 04:47 PM »
Thank you for that's most helpful. Sounds more optical reconnaissance than radar in that kind of orbit.
We are also assuming it is looking down or doing something we already understand...
If you're happy and you know it,
It's your med's!

Offline Star One

  • Senior Member
  • *****
  • Posts: 8260
  • UK
  • Liked: 1338
  • Likes Given: 168
Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #612 on: 05/24/2017 04:48 PM »
Thank you for that's most helpful. Sounds more optical reconnaissance than radar in that kind of orbit.
We are also assuming it is looking down or doing something we already understand...

You think it's a technology demonstrator for something else then.

Offline kevin-rf

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8526
  • Overlooking the path Mary's little Lamb took..
  • Liked: 1028
  • Likes Given: 235
Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #613 on: 05/24/2017 05:26 PM »
You think it's a technology demonstrator for something else then.
I think until people observe it for a while, does it flare, does it tumble, how is it's station keeping, anyone detect emmissions, ect. We can't know... honestly, it is completely out of family for anything the NRO has done to date. 

Honestly, the only thing (DOD related) that has gone to a similar orbit is the X-37 and for some reason, I doubt it's an X-37.
If you're happy and you know it,
It's your med's!

Offline cppetrie

  • Full Member
  • ****
  • Posts: 409
  • Liked: 223
  • Likes Given: 3
Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #614 on: 05/24/2017 08:07 PM »
You think it's a technology demonstrator for something else then.
Honestly, the only thing (DOD related) that has gone to a similar orbit is the X-37 and for some reason, I doubt it's an X-37.
Interesting. Is it possible a previous X-37 flight carried the technology demonstrator in its cargo bay and now they have launched the real deal to a similar orbit?

Offline Star One

  • Senior Member
  • *****
  • Posts: 8260
  • UK
  • Liked: 1338
  • Likes Given: 168
Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #615 on: 05/24/2017 08:08 PM »
You think it's a technology demonstrator for something else then.
Honestly, the only thing (DOD related) that has gone to a similar orbit is the X-37 and for some reason, I doubt it's an X-37.
Interesting. Is it possible a previous X-37 flight carried the technology demonstrator in its cargo bay and now they have launched the real deal to a similar orbit?

That thought did cross my mind when I saw that post.

Offline edkyle99

  • Expert
  • Senior Member
  • *****
  • Posts: 12849
    • Space Launch Report
  • Liked: 3607
  • Likes Given: 617
Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #616 on: 05/24/2017 08:28 PM »
Thank you for that's most helpful. Sounds more optical reconnaissance than radar in that kind of orbit.
Optical recon is usually in a sun synchronous orbit, for good lighting conditions.  This one is not sun synchronous.  It is not in an orbit typically used by optical or radar recon, by ELNIT, by weathersats, by milcomsats, etc.  The only thing it reminds me of, besides the obvious X-37B type experimental orbit, are some of the early Orbcomm store and forward (packet data relay) satellite orbits - but you need a fleet of satellites to make such a system work.

 - Ed Kyle
« Last Edit: 05/24/2017 08:35 PM by edkyle99 »

Offline Star One

  • Senior Member
  • *****
  • Posts: 8260
  • UK
  • Liked: 1338
  • Likes Given: 168
Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #617 on: 05/24/2017 08:32 PM »
Thank you for that's most helpful. Sounds more optical reconnaissance than radar in that kind of orbit.
Optical recon is usually in a sun synchronous orbit, for good lighting conditions.  This one is not sun synchronous.  It is not in an orbit typically used by optical or radar recon, by ELNIT, by weathersats, by milcomsats, etc.  The only thing it reminds me of, besides the obvious X-37B type experimental orbit, are some of the early Orbcomm store and forward (packet data relay) satellite orbits - but you need a fleet of satellites to make such a system work.

 - Ed Kyle

Would you speculate at all on your own thoughts what it might be?

Offline Lars-J

  • Senior Member
  • *****
  • Posts: 3470
  • California
  • Liked: 2700
  • Likes Given: 1729
Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #618 on: 05/24/2017 08:35 PM »
It would be very amusing if the NROL-76 payload actually was another X-37 mission.  ;D

Offline Star One

  • Senior Member
  • *****
  • Posts: 8260
  • UK
  • Liked: 1338
  • Likes Given: 168
Re: SpaceX Falcon 9 - NROL-76 - May 1, 2017 - DISCUSSION
« Reply #619 on: 05/24/2017 09:01 PM »
It would be very amusing if the NROL-76 payload actually was another X-37 mission.  ;D

Next you'll be suggesting it was an EM drive satellite.

Tags: