NROL-76 And The ISS

Flyaway

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Interesting theory. Here are the two relevant blog posts about the topic.

https://sattrackcam.blogspot.co.uk/2017/05/observing-usa-276-odd-nrol-76-payload.html?m=1

https://sattrackcam.blogspot.co.uk/2017/05/usa-276-nrol-76-payload-and-iss-near.html?m=1
 
Someone has been doing some follow up on this whole business.

In recent days, Ars has run these observations by several officials and informed sources. They are credible, these officials say, and curious indeed. "This is strange," said one astronaut who has commanded the International Space Station. "I don't really believe in coincidences. But I can't really think of anything that would be worth highlighting a close approach."

Deliberate or not?

One expert in satellite launches and tracking, Jonathan McDowell, said of the satellite's close approach to the station, "It is not normal." While it remains possible that the near-miss was a coincidence due to the satellite being launched into similar orbit, that would represent "gross incompetence" on the part of the National Reconnaissance Office, he said. Like the astronaut, McDowell downplayed the likelihood of a coincidence.

Another option is that of a deliberate close flyby, perhaps to test or calibrate an onboard sensor to observe something or some kind of activity on the International Space Station. "The deliberate explanation seems more likely, except that I would have expected the satellite to maneuver after the encounter," McDowell said. "But it seems to have stayed in the same orbit."

Another question, if the maneuver was deliberate, is whether the US government informed Russia or other international partners on the space station. The Russian segment of the station controls the thrusters that generally are used to maneuver the station away from orbital debris, so such coordination might seem prudent.

In regard to these questions, so far the US government has declined to provide answers. A NASA spokesman offered to look into the matter on Monday but as of Wednesday afternoon had nothing to say. A query sent to public affairs at the National Reconnaissance Office went unanswered. We will update this story if we receive any official responses.

https://arstechnica.com/science/2017/06/a-spy-satellite-buzzed-the-space-station-this-month-and-no-one-knows-why/
 
if you interpret the articles about NROL-76

it give the impression that NROL-76 was monitoring the CRS-11 mission to ISS
but why do that ?
NROL-76 operate in a 50° inclination, 389 x 409 km Low Earth Orbit. (for the moment)

"nearby" operate the Chinese Tiangong-2 Space Laboratory in 42.79° inclination, 370 x 378 km Low Earth Orbit.
it got visit by the automatic Tianzhou 1 cargo spacecraft.
If NROL-76 is build to monitor rendezvous of spacecrafts
it will in future change it orbit to Tiangong-2 Space Laboratory fly-by.

other option is
that USAF and NRO not care that NROL-76 came close to ISS with in 20.3 km and consider it a save distance.




P.S.
can some one move this in to Aerospace section
the topic is not about unbuild Space hardware
Thanks


... and not about prototypes or one-offs, correct ! ;)
 
Marco Langbroek has published an article about USA 276 in the Space Review:
http://www.thespacereview.com/article/3277/1

My own take on this all is that I think it is possible, but not certain, that the close approach was deliberate and meant to test space-based technologies to monitor grapplings and berthings of third-party objects. If this is correct, I tend to see the coincidence of the flyby with the originally planned Dragon arrival, but also the sudden undocking of Cygnus OA-7 when Dragon CRS-11 was postponed, as related to the technology demonstration. The relevance of the other coincidences is more conjectural: I tend to see the rescheduling of astronaut Jack Fischer as likely unrelated, for example.
 
Dr Marco Langbroek‏ @Marco_Langbroek

What goes around comes around: spysat USA 276 will make another series of close approaches to the #ISS tomorrow: http://satobs.org/seesat/Jul-2017/0053.html
 

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