Prowler captured flaring again

On June 10 of last year (2014) I captured a brief bright flare of Prowler (1990-097E) when imaging it 'remote' with the 0.61-m Schmidt-Cassegrain of MPC G68 Sierra Stars Observatory in California, USA.

Last week on March 7, Prowler again briefly flared while I was imaging it with the same telescope, Note the brightening of the trail near the left end of it:

It is a flare of the same short specular type as that of last year. It was captured in one of three brief 30-second exposure  images taken near 03:45UT: the flare is close to the end of the trail in the second image, i.e. occuring at about 03:45:10 UT (March 7, 2015). Here is a stack of all three images:

These brief specular flares are superimposed on what seems to be another, very slow periodicity in brightness.

Prowler itself is a very interesting, enigmatic object. It was a clandestine launch from Space Shuttle STS-38 in 1990 and long existed in the realm of rumours only. It was a top secret experimental  satellite with stealth characteristics, meant to make close inspections of third party satellites in GEO orbit. I have written an extensive in-depth post on the story of Prowler before which you can read here.

Prowler

Among the family of classified satellites, three stand out as more mystifying than the rest: Misty 1 & 2, PAN, and Prowler.

The latter has long existed in the realm of rumours only. It was launched by Space Shuttle Atlantis on mission STS-38, which was a classified DoD mission launched on 15 November 1990. Officialy only one satellite, USA 67, was launched from the Atlantis payload bay. This is believed to be a geostationary SDS communications satellite, SDS 2-2.

STS-38 mission patch

USSTRATCOM released catalogue numbers (but no public orbit) for three objects connected to this launch: the SDS satellite USA 67 itself (90-097B, 20963) plus two rocket bodies (90-097 C & D, 20964 and 20965).

The latter was puzzling, as it is one too many (see the discussion by Ted Molcan here), This was the start of the idea that a second, unacknowledged object was launched by STS-38 as well.

In 2004 an NBC journalist referred to such a secret payload by the name of Prowler, in a news-item discussing a Senate debate about a classified spy satellite program drawing criticism for massive cost overruns. The same journalist, citing anonymous sources, did so again in 2007.

According to these stories, Prowler was an experimental satellite used for close inspection of other (non-US) satellites in geostationary orbit (see discussion here), reportedly coming to within decimeters of some satellites. There are suggestions that it was a test of technology which, in wartime, could be used to sabotage enemies' space assets. It was also said to employ stealth technologies to evade easy detection.

Meanwhile, US amateur observers Ed Cannon and Mike McCants had discovered an unidentified near-geostationary object in July 1998. As time progressed and more and more ISON and amateur-discovered objects could be identified with specific launches, this one was one of few left unidentified. This in turn led to suggestions that the object in question was the rumoured unacknowledged STS-38 launch, Prowler. It was likely discovered only after its active lifetime ended, and it was put in a disposal orbit (see below).

Since then, a long term analysis by Ted Molczan has strengthened this identification. The object has al the right characteristics in terms of brightness behaviour and orbital behaviour. It currently is in an unusual librating disposal orbit that seems devised to keep it out of reach of Soviet tracking facilities (see discussion in depth by Ted here). In a second analysis, Ted showed that STS-38 indeed had the opportunity to launch this object and some tell-tale clues to that are present in the manoeuvering history of STS-38 Atlantis. The whole history of the object, from launch onwards but also including the final disposal orbit when the stealth character of the object was lost, was designed with low detectability by Soviet tracking facilities in mind (see Ted's discussion here).

The object now resides in a currently 13-degrees inclined orbit librating between 73 W and 136 W, putting it over the eastern Pacific, with visibility from the western United States. Over the past two weeks , I imaged it a number of times, using the 0.61-meter "remote" telescope of Sierra Stars observatory in California. Below is one of the better images, shot on the morning of July 6th:

click image to enlarge

Imaging geostationary satellites using a remote telescope [UPDATED]

I have been using the "remote" telescopes of Sierra Stars observatory in California and Winer Observatory in Nevada for some time now to image asteroids (recently, earthgrazing NEA 2011 MD).

The past two days I have used the Sierra Stars Obs. 0.61-meter Cassegrain telescope to make some "remote" images of classified geostationary satellites that are not visible from the Netherlands, but visible from the western United States. It concerned the recently launched SBIRS-GEO1 satellite (11-019A) and the mysterious object (90-097E) that is most likely Prowler, launched in 1990 on STS-38.

Below are the images: as this is a guided telescope, the satellites have created trails on the images. Top image: Prowler. Bottom image: SBIRS-GEO1, plus an unidentified object (UPDATE: the latter object might be the SBIRS-GEO r/b).

click images to enlarge