Tuesday 27 July 2010

Continued monitoring of the brightness behaviour of the USA 144 decoy (99-028C)

A year ago I started, on the request of Pierre Neirinck, to photographically monitor the brightness behaviour of the enigmatic USA 144 decoy (99-028C). Some details of this curious object are given in the post here.

On the night of July 19-20 I obtained a series of 8 images in two separate groups (2x 4 images with 10s separation each, the two groups being one minute separated). On two images, both part of the 2nd group, the object is too faint to be seen. Hence, the result was 6 segments of brightness behaviour. This yielded the following brightness diagram:

click diagram to enlarge

The data fit a period of 61 seconds. Over the past year, the period was as follows:

25-27 Aug 2009: 71 seconds (see here)
19 Nov 2009: 62 seconds (see here)
2-9 Mar 2010: 88 seconds (unpublished)
20 Jul 2010: 61 seconds (this post)

Clearly, there are regular changes in periodicity, without a clear direction.

One peculiar observation in the current series, is that of an anomalous bright spike in one of the "valleys" of the brightness profile. The satellite is all but almost invisible in most of the image, except for a brief spike right at the end of the exposure (EF 100/2.5 Macro USM, 1600 ISO):

click image to enlarge

I have never observed this before. It looks quite specular, i.e. due to a glint on a flat reflective surface.

As a comparison, here is the object during it's brightest appearance:

click image to enlarge

I'll keep periodically revisiting the USA 144 decoy periodicity.

Sunday 25 July 2010

Manoeuvring KeyHoles and the flashing Iridium 33 wreckage

July 2010 so far yielded a nice series of clear evenings, due to very warm, sunny weather (in most cases allowing observations in shorts and shirt). I observed on July 3, 4, 6, 12, 15, 16, 17 18, 19 and 22.

Two manoeuvring KeyHoles

Prime targets this month were the KH-12 KeyHoles USA 186 (05-042A) and USA 161 (01-044A). These both manoeuvred on the 14th of July, giving us observers a nice task of recovery and renewed tracking.

The manoeuvre of USA 186 (05-042A) was first noted by Pierre Neirinck in France. After some other observers missed it, he observed it being very late, but initially lost his reference points. Ted Molczan next created a number of search orbits, based on different presumed manoeuvre times. Next Alberto Rango and me again recovered the satellite (Alberto first while I still had daytime, then me on the next orbit, in deep twilight), in an orbit very close to one of Ted's search orbits.

Using pre-manoeuvre and post-manoevre orbits calculated by Ted Molczan from our observations, the manoeuvre occurred on July 14th at the ascending equator crossing at about 15:00 UTC, over Indonesia.

Next it turned out that another KH-12 Keyhole, USA 161 (01-044A) had also manoeuvred early on the 14th. Again, Pierre noted it first, observing it 12 minutes late on July 17th. Next Ted and a number of other observers joined the recovery (including me at some point). Using pre- and post-manoeuvre orbits calculated by Ted and Mike from our observations, the manoeuvre ocurred at the ascending equator crossing near 00:20 UTC, July 14th, near Hawaii.

The flashing behaviour of the Iridium 33 wreckage

On 10 February 2009, the American Iridium 33 (97-051C) telephone communication satellite and a defunct Russian satellite, Kosmos 2251, collided in space. A large number of debris pieces were spread over Low Earth Orbit (see here), and the main wreckages of the two objects kept orbiting, now wildly out of control.

The Iridium 33 wreckage (97-051C) made some fine passes last month, displaying the same kind of flashing behaviour due to tumbling that I also observed shortly after the collision in 2009 (see here, here and here). Some of these flashes are easy naked eye flashes, reaching mag. +0. The object interchanges bright flashes like these with (more numerous) fainter flashes in the +4 range.

I targetted the satellite wreckage several times this month to determine the flashing behaviour. In March 2009, it showed a period of 4.7 seconds. Analayses of the imagery of the past few nights, shows this has changed to about 3.1 seconds. Below is one of several images, taken on July 16th, showing a series of fainter and brighter flares:

click image to enlarge

Below are graphic representations of the flare positions (yellow dots) observed on consecutive nights (resp 16-17, 17-18, 18-19 and 22-23 July 2010). Please note: only flares happening during photographic exposures are shown here. There were more flares, but these happened while the camera wasn't open:

click maps to enlarge

(maps made using Heavensat)

An unusual flare was captured on July 17-18, consisting of a triple flare with flares within 0.5 seconds:

click image to enlarge

Other objects besides the KH-12 Keyholes USA 161 and USA 186, and the Iridium 33 wreckage observed last 3 weeks include:

- the geostationary objects Milstar 5, Mentor 2 and Mentor 4 (USA 202);
- the HEO objects USA 184, the USA 40 rk;
- the LEO objects Progress-M 04M, MSX, Lacrosse 5, the Lacrosse 5r, IGS 1B, the IGS 5r, USA 32, the NOSS 3-3 duo and the USA 144 decoy,;
- plus a large number of GEO and LEO strays.

I have yet to analyse the USA 144 decoy (99-028C) data from July 20 for a new tumble period determination.

Friday 16 July 2010

Ozzie space junk dreams

Northern Hemisphere summertime is the usual period that the news is lazy, and strange mistaken news items pop up like another sighting of the Loch Ness Monster, Bigfoot, chickens that came before the egg (or not), and now an Ozzie corporation that thinks it can solve the space junk threath by selling tracking data from to-be-build tracking lasers.

This company must live in the Dream Time. It is not tracking itself that is the problem. USSTRATCOM basically tracks everything 10 cm+ in LEO plus a lot smaller stuff. The real problems, are problems that additional laser tracking data is not going to solve:

a) the lack of computer power to determine which detections concern the same object;

b) most importantly: the lack of computer power to timely calculate risk situations for thousands of objects in dynamic orbits.

Friday 2 July 2010

The brightness behaviour of USA 32 on 26 June

On 26 June I captured the 22-year-old ELINT USA 32 (88-078A). It displayed a regular brightness variation while passing through the zenith:

click image to enlarge

Below is the resulting brightness profile, and a diagram showing the delta T (in seconds) between brightness peaks. The period between the major peaks is regular and near 1.20 seconds. This is similar to what I determined for this satellite in January 2009 (see my post here). There is a hint of 2 lesser peaks present between each main peak.

click diagrams to enlarge

Thursday 1 July 2010

Progress-M 04M, MSX, and Mentor 2

A long spell of very warm, sunny weather is resulting in several clear nights. Since my last observations reported here (those of June 2nd), I have been able to observe on June 3, 13, 14, 16, 17, 22, 24, 26 and 29. Objects include Progress-M 04M, Mentor 2, Mentor 4 (USA 202), USA 161, USA 32, USA 184, MSX, Milstar 5, the NOSS 3-1 duo, and the STSS Demo-1. This does not include a number of non-classified strays also captured.

USA 161 (01-044A) slowly flared to -1 at 23:58:59 UTC (24 Jun).

Below are a few pictures. First: UARS captured as a stray, flaring, on June 16th:

click image to enlarge

Progress-M 04M on 26 and 29 June:

click images to enlarge

Geostationary USA 202 (Mentor 4), in the trees low in the sky (altitude about 17.5 degrees):

click image to enlarge

Mentor 2 (geostationary), MSX and a stray (HJ-1A, a Chinese Earth Observation Satellite)

click image to enlarge