Updating the changing tumble period of the USA 144 decoy

click diagram to enlarge

The diagram above shows the brightness variation of 1999-028C, the USA 144 decoy, as determined on 21 May 2017. It was created from photometry on video records spanning several minutes of a pass using a WATEC 902H with a Samyang 1.4/85 mm lens. The photometry was obtained using a not-yet-public beta-version of TANGRA.

The brightness of the object shows a slow variation between mag +7.2 and invisible. Fitting a sinusoid gives a peak-to-peak period of 43.528 seconds, +/- 0.005.

I have written on this enigmatic object before on this blog. It was launched from Vandenberg 18 years ago, on 22 May 1999, as NROL-9. This launch is widely believed to have launched the second Misty stealth satellite. Following the launch amateurs found this relatively bright object in a (currently) 2668 x 3150 km, 63.4 degree inclined MEO orbit. The object shows a periodic brightness variation.

This object is, however, not Misty 2. A long term analysis by Ted Molczan showed that the object has an unusually large surface-to-mass ratio in the order of 0.09 m²/kg and its orbit is subject to considerable Solar Radiation Pressure (SRP) effects. The surface-to-mass ratio is an order of a magnitude larger than for normal satellites, suggesting this is something large and lightweight - e.g. something inflatable, so large and light that pressure from sunlight has an effect on its orbit.

We have come to believe that it is a decoy, designed to lure attention away from the real, stealthy USA 144 payload when it was launched in 1999.

As the result of SRP influence, the tumble rate is variable over time: in the order of 60-90 seconds 7-8 years ago, 50 seconds 2 years ago (see here), and now 43.5 seconds.

The slow, changing tumble of the USA 144 (Misty 2) decoy

The USA 144 Decoy (1999-028C)
(click image to enlarge)

Yesterday evening I did some observations on the two evening KH-11 Keyholes (USA 186 and USA 245). Following that, I targeted the USA 144 decoy (1999-028C), an enigmatic object from the launch of the stealth satellite Misty 2 in 1999.

Three classified objects and one unclassified: the USA 144 Decoy, NOSS 3-4 A & C,
and an old rocket booster with CAMEO attached
(click image to enlarge)

At left in the image above is a double trail of the classified NOSS 3-4 duo (2007-027 A & C). In the middle is an old Delta 1 rocket booster (78-098B) with CAMEO on top, an earth magnetosphere experiment from 1978. At right, the shortest trail, is the enigmatic classified object we call the USA 144 Decoy.

I have written about this enigmatic object before. It is a bright object in a high 2665 x 3155 km orbit originating from the Misty 2 Stealth satellite launch in 1999.

(click image to enlarge)

From a study of its orbital behaviour, Ted Molczan found that the orbital decay of this object is notably influenced by Solar Radiation Pressure (SRP). This suggests an object that is very "light" relative to its size, i.e. an object with a large area-to-mass ratio. This does not fit a normal payload, so we suspect that this relatively bright object might have been a decoy to attract attention away from the real, stealth payload.

The USA 144 Decoy is slowly tumbling, resulting in a clear brightness variation. Ted already noted that the period of this variation changes over time, sometimes increasing, sometimes decreasing. This is in line with the tumbling behaviour of other known objects subject to SRP (like fragments of the PAGEOS balloon satellites).

click diagram to enlarge

I took a series of images between 20:19:42 UT and 20:26:12 UT (20 Sep 2015) documenting the brightness variability. The curve fits a peak-to-peak period of about 50.5 ± 0.5 seconds (see diagram above). There is clearly much variation in amplitude peak-to-peak.

The period found, is shorter than the periods found during my earlier determinations in 2009 and 2010, a summary of which is given below:

20 Sep 2015:    50.5 seconds (this post)
5 Sep 2010:     60 seconds   (see here)
20 Jul 2010:    61 seconds   (see here)
2-9 Mar 2010:   88 seconds   (unpublished)
19 Nov 2009:    62 seconds   (see here)
25-27 Aug 2009: 71 seconds   (see here)

This variation of the period over time is in line with expectations for an SRP-influenced object like this.

An Unidentified geostationary object

Yesterday evening was (initially) very clear. I took the opportunity to image the USA 144 decoy (1999-028C)  in the early evening, and then do a survey of the eastern geostationary belt between 23h and 24h LT.

The USA 144 decoy passed close to the Andromeda Galaxy (M31) and was caught together with this galaxy and a Breeze-M tank (2011-021C, from the Telstar 14R launch):

click image to enlarge

The session on geostationary satellites later in the evening was ended by incoming cirrus, but not before a fair number of objects was imaged.


A UNID geosat in Orion

Among them was a bright unidentified object in an 8-degree inclined (near-) geostationary orbit captured in several images.

The images below (overview, and then details) show it in Orion together with the Orion nebula, a Chinese r/b (Beidou CZ-3C r/b, 2010-024B), and the classified SIGINT objects Mentor 5 (USA 237, 2012-034A) and Vortex 6 (1989-035A).

click images to enlarge

While the object is unidentified at the moment, it probably is a commercial geostationary satellite that is being moved to a new slot or to a graveyard orbit: but with the tracking network of USSTRATCOM not having noted this yet.

For the moment, the object has been designated as Unknown 121118. It moves in this very approximate orbit (calculated by Mike McCants):

Unknown 121118
1 99991U 12009B   12323.84298080 0.00000000  00000-0  00000-0 0    02
2 99991   8.1179  50.0556 0005003 274.8696  85.1304  1.00270000    07

Initially, I thought it might be the same "unid" reported by Greg in the same general area the day before, but it turns out to be another object. Greg's "unid" was identified by Mike as 2010-024B, a Beidou CZ-3 r/b, actually the same object that can be seen close to USA 237 in the images above.

UPDATE 19-11-2012, 20:20 UT: Greg Roberts just mailed me that he recovered the UNID from South Africa at virtually the same position, so it is geostationary. See follow-up post here.

KH-12 USA 129 and a Chinese rocket stage (CZ-2C r/b) cruising up together

Tuesday evening, the sky was very hazy and a waxing moon was high in the sky. Conditions were hence abominable, but I managed to capture both evening KH-12's, USA 129 (96-072A) and USA 186 (05-042A). The pictures are not pretty, as they are quite fogged.

The pass of USA 129 was confusing, as a second bright object close to it was moving parallel to it: at the moment of observation, I was not sure which object was the Keyhole and what the other object was! It took me rather by surprise (and as a result, I mis-aligned the camera for the second image, resulting in only one image).

It turned out to be a Chinese Long March rocket stage, a CZ-2C r/b (09-061B) from the launch of Shijian 11-01 on November 12, 2009. Below is the image, showing them cruising up together in a moon-fogged sky:

click image to enlarge

A few days earlier, on 11 March, I observed USA 186 (05-042A), Lacrosse 5 (05-016A) and the USA 144 Decoy (99-028C). I obtained a series of images on the latter, and hopefully these can be employed for a brightness variation reconstruction again (to be reported on later, after I have had some time to do the analysis).

Lacrosse 5 was racing against an untimely field of clouds that evening, yielding this picture of a bright satellite trail and a wisp of moving cloud:

click image to enlarge

The satellite did it's "disappearance trick" again during culmination north, reappearing very brightly for a brief period after it.

Earlier that evening, in a still mostly clouded sky, I saw METOP-A flaring brightly to at least -3 at about 20:09:20 UTC (March 11).

FIA Radar 1 and a flaring Topex near the Andromeda Galaxy

In the evening of Februari 8 I observed the KH-12 Keyhole USA 129 (96-072A) which is becoming visible for my location again, and the FIA Radar 1 (10-046A).

The latter moved close to M31, the Andromeda Galaxy. In the same image is another satellite, Topex (92-052A), which is flaring (it is present in a second image too). All together, this yielded this nice image:

(click image to enlarge)

Topex was part of a joint US/French oceanographic experiment. Launched in 1992, it functioned up to 2005. With the loss of attitude control since it ceased functioning, it has started to tumble, producing flashes.

I also observed the FIA Radar 1 on February 3rd, together with the USA 144 decoy (99-028C)

Yesterday, on Februari 12th after a day full of drizzle, it unexpectedly cleared around midnight, allowing me to photograph the geostationary SIGINT satellite Mentor 2 (98-029A) which at that time was just south of Procyon:

(click image to enlarge)

Again the USA 144 (Misty-2) Decoy brightness variability, with another specular glint

Since about a year, I am regularly targetting the enigmatic object (related to what was probably the Misty-2 stealth satellite launch) we call the USA 144 Decoy (99-028C) as part of a long term monitoring of the brightness variability of this object. It shows a slow sinusoid brightness variation with a periodicity of tens of seconds. This period of variation slowly evolves over the course of months.

On the night of September 5-6 I captured a series of images again (between 23:11:22.30 - 23:16:32.35 UTC, Sep 5, 2010) allowing the construction of a curve. Below is the diagram: I find it best fits a periodicity of 60 seconds:

click diagram to enlarge

Earlier period determinations were:

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

I should actually revisit the two determinations (Aug 2009, Mar 2010) that are well off from 60 seconds to see whether I didn't make mistakes there.

As can be seen, I again captured a solitary anomalous glint produced in the "valley"part of he curve. Something very similar happened earlier on July 20th. Both glints happened near a brightness minimum. Below is imagery of the latest glint from September 5 (showing one image before the glint, then the glint image, and an image after the glint), and a comparison diagram of the July 20th and September 5th glints:

click image to enlarge

click diagram to enlarge

These spikes are quite specular in character, and suggest there is a flat mirroring surface attached to the object on (if the slow brightness variation of the object is due to exposure of long versus narrow sides) one of the narrow sides.

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.