Wednesday 22 August 2012

Imaging MiTEx 2

In 2006, the USA launched two experimental geosynchronous satellites, MiTEx 1 and MiTEx 2 (2006-024A and 2006-024B). MiTEx is an acronym that stands for Micro-satellite Technology Experiment. These small satellites were reportedly a technology demonstration and a project of DARPA, the US Air Force and US Navy. Being small (225 kg each) and hence difficult to detect, they explored the possibility of covertly sneaking up on and inspecting other satellites. In this sense, they appear to be part of the Prowler legacy.

In 2009, both the MiTEx satellites were used to inspect the classified US military DSP-23 satellite which had malfunctioned on-orbit in 2008 and had started to drift, physically endangering other satellites and interfering with their radio communications. This inspection was actually observed by amateur trackers in the UK and South Africa.

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Since both satellites are small, they are faint and difficult to image. It requires large instruments. On 11 August 2012, I imaged MiTEx 2 using the 61-cm telescope of Sierra Stars Observatory. It is the faint trail in the image above (which is a 30-second CCD exposure guided on the stars).

This is not the first time though that I have imaged one of the MiTEx-es  (for example, the image of MiTEx 1 here, which happens to be the last positive observation before we lost that object, perhaps due to a manoeuvre: in fact, it was already slightly off its predicted position that March 15).

Tuesday 21 August 2012

"Spying on the spooks" and other recent media coverage of my activities

Jeff Shear has just published a background piece on amateur satellite observations, largely based on my activities, in the Pacific Standard: "Spying on the Spooks".

Earlier this year, Ann Finkbeiner wrote a similar piece for the "The Last Word on Nothing" science blog: "Watching the Watchers".

A few minor corrections to the "Spying on the Spooks" story: the total number of objects we track is closer to 300 (not 100), and I didn't discover the asteroid (183294) that was named after me: Stefan Kürti/NEAT did.

Monday 13 August 2012

CBERS 2B flash pattern

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Last night I set up the camera with a Tamron 2.8/17-50mm lens set at f3.2/17mm to run automatically (using an Aputure timer), in order to catch some Perseids.

AS part of the image series, I captured a satellite showing a regular flash pattern. The top image above is a stack of 7 images of 20s each, showing the repeated flashing (including a brighter flare).

It turned out to be CBERS 2B (07-042A) which was launched from China on 19 September 2007 as the third Chinese-Brazilian Earth Resources Satellite. It ceased operations in June 2010.

By measuring the positions of the flashes and relating these to a recent TLE, I was able to determine the flash pattern. It is a combination of two series: one with flashes each 23.7s (series a), and another one (which includes the bright flare) with flashes each 47.4s (series b). The latter is the double of the series a period. The sequence of flashes is a-a-b-a-a-b-a-a-b but the b-flashes are not nicely in the middle of the a-series flashes.

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The two series probably relate to different reflective surfaces. The flashes from series a are conspicuously orange, while those from series b are bluish-white.

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As can be seen on the CBERS website, the satellite body itself is wrapped in orange insulation foil, suggesting the orange flashes could be reflections from the satellite body. The bluish-white flashes could be from the solar panels. The satellite would then rotate once each 94.8 seconds during which 2 solar panel flares and 4 body flares (4 sides of the cubus) can be seen.

CBERS 2B was not the only satellite captured flaring this night: I'll report on the other later. Amongst others, Envisat was seen flaring again.


I indeed captured some meteors as well: 7 Perseids and one sporadic meteor. Here is a nice Perseid:

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Sunday 12 August 2012

OT: night-sky time lapse, Dolomites

The movie above, which you should see on full resolution rather than in the small embedded version above, is a time-lapse I made using images shot during my holidays in the Dolomites.

The movie starts with imagery shot from Aldein (Aldino) at 1188m over a 4h42m period on July16. Apart from stars and  at about 20s in the movie the Milky Way entering the FOV, a number of satellites (and aircraft) are visible.

The movie ends with a (too) short clip of stars circling the celestial pole, based on a 25 minute image series shot from Vajolet at 2238m, in the Dolomites properly, on 23 July.

All images were made using the Canon EOS 60D + Tamron 2.8/17-50mm at 17mm, 2000 ISO, 30-second exposures.

Thursday 9 August 2012

ENVISAT and other satellites flaring over the Italian Dolomites

During the second half of July, I travelled through northern Italy, including an 8-day mountain hike from mountain hut to mountain hut through the high Alpine parts (up to 2770 m) of the Rosengarten Dolomites. The latter mountains are truely marvelous, and perhaps the most beautiful mountains I have ever seen.

During two clear evenings I did some limited astrophotography: limited, as because of weight considerations I had only two lenses with me  (a Canon EF 100mm Macro and a Tamron 17-50mm zoom) . After all, we already had to carry 16 kg on our backs every day while scaling the mountain.

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The image above was shot at 2238m altitude from Rifugio Vajolet on July 23rd. It shows ENVISAT (02-009A) flaring. Since contact with this legendary Europe remote sensing satellite was lost on 8 April 2012, it appears to have started to tumble. Two brightness maxima (one brighter and one fainter preceding it) are visible on the original of the above 30 second exposure, and other (faint) maxima are visible on an earlier and on subsequent images.

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A 45 image series (30s exposure each) from the same location was used to create the above image of startrails circling the celestial pole. The mountain at right is the 3004m high Kesselkügel.

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A few days earlier (16 July), while at lower altitude (1188m) in Aldein (Aldino) where we visited the nearby Bletterbachschlucht, I shot this image of a double Iridium flare. The brighter of the two is Iridium 63, the other one is Iridium 14. The classified Japanese satellite IGS 7A (11-075A) can be seen as well as a fainter steady trail near the center of the image (the original image has 3 more very faint satellite trails as well). The bright star top right is Arcturus.

All images were made with a Canon EOS 60D at 2000 ISO (and part of image series driven by a programmable timer) using a Tamron 2.8/17-50mm set at 17mm.

Wednesday 8 August 2012

The re-entry of IGS 1B on 26 July 2012

While I was away on holidays, the Japanese spy satellite IGS 1B (03-009B) that malfunctioned in March 2007, re-entered on 26 July 2012, over Polynesia.

The demise of this satellite was covered for over a year on this blog: as the satellite was weighing 1.2 tons and as it had an unknown amount of remnant fuel onboard, the uncontrolled reentry raised some questions and initial concerns (see coverage here).

The last amateur observations of the object were done by Mike Waterman (USA) on July 24th and Alain Figer (France) in evening twilight of July 25th. The last amateur orbital update by Ted Molczan based on a.o. Mike Waterman's observations, showed it to have descended to a 211 x 213 km orbit on July 24th and analysis of this dataset by this author using Alan Pickup's SatEvo suggests reentry on July 26, somewhere between approximately 9:50 and 10:50 UTC.

USSTRATCOM published a final TIP for IGS 1B on July 26th (that they did so for a classified object is unusual), placing re-entry at 26 July 2012, 09:52 +/- 2 min UTC, near 25 S, 186 E, which is near New Zealand. This is at the start of the reentry window given above and hence seems very reasonable even though the reentry coordinates are a verbatim copy (down to one decimal) of a pre-decay prediction issued at 7:34 UTC (only the uncertainty value has changed, from 2 hours to 2 minutes). No details on the orbital development in the final few revolutions were given.

The map below shows the USSTRATCOM determined reentry location and final trajectory. In principle, the re-entry could have been observed from the northern islands of New Zealand and potentially the Fiji-Tonga area. Note that only half a revolution later (about 30 minutes later) it would have passed over NW Europe and next west Africa.

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The diagram below shows the orbital evolution in terms of apogee and perigee altitudes, from malfunction early 2007 to decay on 26 July 2012. It is based on orbital element sets calculated by Mike McCants and Ted Molczan from amateur observations, including mine:

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IGS 1B was a nice object to observe over the past years: it was bright, and it was interesting to follow its orbital evolution towards decay. The observation that remains the most vivid imprint in my memory is the one that resulted in the picture below: on 2 September 2011, while I was watching and photographing a pass in a slightly hazy sky, the satellite brightly flared to at least magnitude -8 if not more: the brightest satellite flare I have ever seen. I was jumping up and down and yelling "WOOOOOWWWW!!!!" when this happened. It resulted in this wonderful, eerie picture:

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