Monday, September 15, 2014

Rosetta's landing spot. In 3D. Woah!

image: ESA

Put on your red-cyan glasses and take a look at the image above (high-res here on the ESA website). It is the chosen landing site of Rosetta's Philae lander on comet 67P/Churyumov-Gerasimenko. Woah!

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Saturday, September 13, 2014

KH-11 USA 186 has stabilized its orbit

Note 15/09/2014 9:25 UT: corrected inadvertent apogee - perigee mix-up in 4th paragraph
USA 186 passing in early twilight of the evening of Sept 12, 2014
(click image to enlarge)

At the end of May, Northern hemisphere observers lost visibility of KH-11 Keyhole/CRYSTAL USA 186 (2005-042A) when the midsummer nights became too short. The orbital plane of the satellite was still drifting at that time, a process that started after a manoeuvre in mid-November 2013 (see earlier posts on this blog). The big question was, when that drifting would stop. I expected that when the satellite reached its new intended orbital plane it would manoeuvre into a stable sun-synchronous orbit again.

It now has done so, having manoeuvered probably on or near July 1. The orbital plane drift has stopped.

Kevin Fetter in Canada made a chance recovery of the satellite, the first post-summer glare-out sighting, on September 8: he was looking for another object and saw a "unid" in Low Earth Orbit pass through his field of view, that Cees Bassa was quick to identify as USA 186, in a new orbit. Over the next nights several other observers tracked it (including me on Thursday and Friday evening) yielding a first version of the new orbit it is in.

USA 186 passing close to Arcturus (top left) in the evening of Sept 11, 2014
(click image to enlarge)

The satellite has drastically lowered its perigee apogee by almost 500 km, and gently raised its apogee perigee by a few km. It is now in an approximately 265 x 440 km, 96.9 degree inclined orbit. This orbit is sun-synchronous again.

This means that the RAAN drift relative to the other satellites in the KH-11 constellation that had been going on since mid-November 2013, has stopped. It has finally settled at a RAAN distance of about 25 degrees from USA 245 (2013-043A), the primary West plane KH-11.

Comparing the new orbit to the old orbit suggests that the manoeuvre into the new orbit happened on or near July 1st.

In all, the satellite has kept itself pretty much to the expected scenario which I outlined on this blog in several posts in October 2013, e.g. here and here. Following the launch of USA 245 (2013-043A) into the primary West plane of the KH-11 constellation in August 2013, I had predicted that:

1) USA 186, at that time the primary West plane satellite, would migrate its orbital plane to the secondary West plane; 
2) USA 129, the extremely aged satellite in the secondary West plane, would be de-orbitted;
3) after a period of drifting, USA 186 would manoeuvre back into a sun-synchronous orbit again, stopping the RAAN drift, when reaching the intended plane location of the secondary West plane;
4) that in that manoeuvre it would drastically lower its apogee from near 1000 km to near 400 km and gently raise its perigee.

This all has basically happened. It differed on details with my predictions, but the bigger picture is pretty much as I anticipated.

What was somewhat unexpected, is that the satellite had its RAAN drift to a much larger distance with respect to the primary West plane (now occupied by USA 245) than I had anticipated. I expected 10, maybe 20 degrees. It turned out to be almost 25 degrees.

The perigee, although indeed raised, is slightly lower than I expected. The massive lowering of the apogee is exactly how I expected it to be however.

The current orbital plane makes it make passes near 8 am and 8 pm local time.

Meanwhile, there are indications that USA 245 (2013-043A) in the primary West plane has manoeuvered. Russell Eberst still observed it in it's last known orbit from Scotland on Sep 7. Then Bjorn Gimmle from Sweden observed an unknown object on Sep 10, that I suspect is USA 245 after a perigee raising orbital manoeuvre conducted between Sep 7 and Sep 10.

[note 14/09/2014: Mike McC identified Bjorn's object as a Russian r/b near decay]
[note 15/09/2014 9:25 UT: corrected inadvertent apogee - perigee mix-up in 4th paragraph]

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Thursday, September 11, 2014

[Updated] You Only Die Twice: the confusing end of the Russian Kosmos 2495 Kobalt-M spy satellite mission

Update 15:00 UT, Sep 11: a very brief update confirming the object was artificial is provided at the end of this post

Introduction: a spectacular fireball over the USA on September 2-3

In the evening of September 2 (in local time: early September 3 in UT), 2014, a spectacular event was seen and filmed in the skies over the southwestern States of the USA. A very slow fireball crossed the skies, seen by many casual eyewitnesses in several US States who reported their observations to the American Meteor Society (AMS). It was also captured by a number of all-sky video stations. A very nice compilation of images and what is known and what is still debated, has been made by Spaceflight101 on their website. Below is imagery of the event by Thomas Ashcraft from near Lamy, New Mexico:

video footage  by Thomas Ashcraft, New Mexico, USA

The event happened on September 3, 2014, between 4:31-4:33 UT (the evening of September 2 in local time) and was seen from Colorado, Wyoming and New Mexico. A very slow fireball, with a duration of at least 40 seconds and variable in brightness in what looks like a semi-regular pattern, moved across almost 180 degrees of sky. It penetrated deeply into the atmosphere, leaving a debris cloud at low altitude lingering for 30 minutes, detected by Doppler weather radar.

Lingering debris cloud on Doppler radar after the event (image: Rob Matson)

Initially seen as a meteor event, it was somewhat ignored by the amateur satellite community until brought to their attention a few days later.

Suspicion of a satellite re-entry

The suspicion arose that this was in fact a satellite re-entry, with the prime candidate being Kosmos 2495 (2014-025A), a Russian Kobalt-M/Yantar 4K2M photoreturn spy satellite. This is a satellite that uses analogue film rather than electronic image sensors. The exposed film is returned to earth in three recoverable return capsules, the last of which also returns the camera (for re-use).

In terms of duration, the September 2-3 event is a borderline case: with a duration of at least 40 seconds but possibly a minute or more, both a very slow 11.8 km/s meteoric fireball of asteroidal origin, or the decay of an artificial satellite are possibilities. [but see update at the end of this post: NASA camera data show it was not a meteor but an object entering from Low Earth Orbit, i.e. a satellite]

Timing and path over the sky however closely match predictions for Kosmos 2495. The observed object passed only ~3 minutes earlier than the predicted pass of the satellite, in a very similar trajectory. This actually fits with a decay, as in a lower orbit the object starts to slightly speed ahead of an object in a similar but higher orbit. The slight eastern displacement of the sky track also fits with this: in a few minutes time, the earth rotates under the orbital plane slightly, displacing the sky track westwards.

Predicted Kosmos 2495 sky trajectory for Thomas Ashcraft's site in Lamy, New Mexico. Note remarks in text about slightly eastward displacement of trajectory for a slightly earlier passing object in the same orbital plane, relative to the sky trajectory shown here
(click image to enlarge)

As this satellite should have been in earth shadow at that time of the event and hence not illuminated by the sun, it is immediately clear that if this was Kosmos 2495, it was in the act of re-entering and already producing a plasma envelope (a fireball).

[paragraph slightly rewritten 12:10 UT, Sep 11]
But why? The last known orbital element set for the satellite with epoch 2 Sep 17:12 UT show it at an orbital altitude too high for an imminent natural decay.

JSpOC however issued an "administrative decay" for the satellite early on September 3, an indication that it has been deliberately de-orbited.

Yet it was unlikely that the Russian military intended this satellite to re-enter over the USA  instead of over Russia itself, or over the Pacific.

So, if this was Kosmos 2495, did something go wrong? It initially looked like it.

Then came the confusion

Then came the confusion. On the Seesat-list, Ted Molczan reported having received reports of sightings of a re-entry earlier that same day, near 18:14 UT on September 2, seen over southwest Kazachstan. A number of video's exist of this event and show a glowing object followed at some distance by a cloud of glowing fragments.

footage from Kazachstan

The location of these observations, timing and general direction fits well with an object on a trajectory to Orenburg in Russia, the designated touchdown locality of the Kobalt-M re-entry capsules. Indeed, the timing of the observations (~18:14 UT) matches a pass of Kosmos 2495 over the area, and the trajectory of the latter indeed brings it over Orenburg near that same time.

So if this was the Kosmos 2495 re-entry over southwest Kazachstan and the Kaspian sea, then what was it that re-entered over the USA 10 hours later?

In denial

Next, the Russian military weighed in and flatly denied that anything went wrong with Kosmos 2495, implicitly suggesting that the object decaying over the USA was not their satellite (spoiler: it nevertheless likely were parts of the satellite, see below).

Multiple parts

For a solution of this confusion, we have to look at the construction of a Kobalt-M satellite, and previous Kobalt-M missions. An excellent and detailed description of the Yantar/Kobalt satellites translated from a Russian publication can be found here on Sven Grahns website.

We have to realize that the Kobalt-M satellites are made up of multiple modules:

1) The Equipment Module (AO) that contains the main power and propulsion systems;
2) The Instrument Module (PO) that contains electronic equipment necessary for the control and functioning of the satellite;
3) The camera re-entry vehicle (OSA), containing the camera and the last batch of film. This is a true re-entry vehicle, designed to survive re-entry through the atmosphere for recovery of the camera and film. The target area for these re-entry vehicles is near the Russian town of Orenburg;
4) a 2.5 meter sun shade with additional antennae and sensors on the tip of the OSA, that is presumably jettisoned at re-entry.

The satellite also has two additional small re-entry and landing capsules for the recovery of film mounted on the side of the OSA: these are jettisoned for re-entry at 1/3rd and 2/3rd into the mission, so should no longer have been present on Kosmos 2495 on September 2.

Of importance is that the OSA re-entry module eventually separates from the satellite for re-entry. This potentially leaves satellite parts in orbit after the OSA re-entry, even though it is generally believed that the AO and PO go down with the OSA, with the AO providing the retrofire burn for the de-orbit of the OSA.

Re-entry of the Kosmos 2495 OSA return vehicle observed over Kazachstan towards Orenburg at 18:14 UT, Sep 2

The event seen from Kazachstan was, given the location and timing, most likely the OSA return vehicle with the camera and film re-entering the atmosphere for recovery at Orenburg. The single object in front visible in the videos is likely the returning OSA itself. The cloud of fragments at some distance behind it, might be the jettisoned sun shade disintegrating in the atmosphere. It could also be the AO (propulsion) module, the PO module, or both (it is believed by analysts that the AO (propulsion) module is providing the retrofire boost necessary for the de-orbit of the OSA re-entry vehicle. It is believed that the OSA does not have its own retrofire rocket).

Additional Kosmos 2495 parts surviving until re-entry over the USA at 4:30 UT, Sep 3

How does this fit in with the observations over the USA 10 hours later?

A clue is provided by previous Kobalt-M missions. At the end of five of these (Kosmos 2410, Kosmos 2420, Kosmos 2427, Kosmos 2445 and Kosmos 2462) pieces of debris were detected and catalogued by US tracking facilities that survived for several hours after the OSA re-entry vehicle touched down at Orenburg. In four of the five cases, it concerns two debris pieces (the fifth case, Kosmos 2462, produced three pieces). These debris pieces had the following SSC catalogue numbers and usually Cospar sub-designations C and D, or D and E:

For Kosmos 2410: 28501 and 28502
For Kosmos 2420: 29258 and 29259
For Kosmos 2427: 32048 and 32049
For Kosmos 2445: 33969 and 33970
For Kosmos 2462: 36821, 36822 and 36823
Of interest is that these debris pieces are only detected at the very end of the Kobalt-M mission, around the time of the OSA return vehicle re-entry at Orenburg. They hence seem to have to do with alterations to the satellite in preparation for the OSA separation and re-entry. As it happened on at least five of the missions, it seems a normal element of these missions. In fact it might have happened on all missions, but not all might have been detected: most of the objects above have only one or two element sets released indicating short detection spans. Their lifetimes typically are no more than a few hours to a day, so they can be missed.

From the catalogued orbits of these debris pieces, there are suggestions that the separation of these objects from the original satellite body actually happens a few hours before the OSA re-entry. For Kosmos 2410, this is very clear as the debris pieces were first detected some 16 hours before the OSA re-entry, and while the A-object (presumably containing the OSA) was still being tracked.

The likely re-entry seen from Wyoming, Colorado and New Mexico 10 hours after the OSA re-entry vehicle return over Orenburg, could very well concern similar debris pieces generated by Kosmos 2495. Analogues from another Kobalt-M mission suggests this is a realistic option.

The Kosmos 2445 analogue

Kosmos 2445 (2008-058A), another Kobalt-M mission from 2009, provides a very nice analogue. On its last day of existence it produced two debris pieces with catalogue numbers 33969 and 33970, that survived for several hours after the OSA re-entry. The OSA return occured on 23 Feb 2009 at 16:15 UT. We know this because this OSA re-entry was observed, as reported by Lissov. The last available tracking data for the two Kosmos 2445 debris pieces have an epoch near midnight of Feb 23-24, 2009, indicating survival for at least 8 hours after the Kosmos 2445 OSA return at Orenburg.

I have used Alan Pickup's SatEvo software to further analyse the likely decay time for these debris pieces: the analysis suggests decay near 1:30-1:40 UT on 24 Feb, 2009. This is 9.5 hours after the OSA return.

This 9.5 hours survival time of the Kosmos 2445 debris pieces is similar to the time difference between the Sep 2, 18:14 UT Kosmos 2495 OSA return observed from Kazakhstan, and the possible decay event observed over the USA at Sep 3, 4:30 UT. The time difference between these is about 10 hours, which is not much different from the ~9.5 hours for the Kosmos 2445 debris in 2009.

During their last few orbits in February 2009, the Kosmos 2445 debris pieces C and D moved somewhat in front of where the A-object (the part including the OSA re-entry module) would have been had it not been de-orbitted. The difference in pass time was a few minutes.

Relative position of Kosmos 2445 C and D debris pieces a few minutes in front of where the A-body would have been, just before decay early Feb 24, 2009 (movement is top to bottom)
(click image to enlarge)

This again provides a nice analogue to the September 2-3 event over the USA: the decaying object observed from the USA moved along the Kosmos 2495 A-object trajectory, but passing 2-3 minutes earlier than the predicted A-object passage (i.e., it was moving slightly in front of where the A-object would have been had it not been de-orbitted over Orenburg). Also note the slight westward displacement of the A object (red) trajectory.

So: likely Kosmos 2495 debris re-entering over the USA after all!

I feel that this all justifies to conclude that what was seen from the USA on the evening of September 2-3, indeed were parts of Kosmos 2495 re-entering. The close agreement of the observed fireball track with the predicted trajectory and predicted pass times for Kosmos 2495 is too good to be likely coincidence. The whole event moreover fits patterns of previous Kobalt-M missions, notably that of Kosmos 2445 in 2009: debris pieces surviving for a few hours after the OSA return vehicle re-entry, decaying ~ half a day later.

So while it was not the return capsule with the camera and film that re-entered over the USA, it were nevertheless almost certainly parts of Kosmos 2495.

Remember that denial (see another version here) by the Russian military? Read it carefully. What they actually deny is that Kosmos 2495 exploded, and they say "that nothing out of the ordinary happened".

That is true. The return capsule separated successfully and presumably landed safely at Orenburg near 18:14 UT, as observed from Kazachstan. And Kosmos 2496 did not explode over the USA: debris parts left after the OSA separation decayed over the USA. Generation of such debris pieces seems to be normal for a Kobalt-M mission. So yes, "nothing out of the ordinary happened". It is all a clever word game.

On the nature of those debris pieces

What the nature of those debris pieces generated at the end of most (if not all) Kobalt-M missions and probably seen decaying over the US exactly is remains unclear. Behind the scenes, several independent analysts including me have had e-mail discussions about this the past 24 hours. Separation of the Kosmos into three modules (AO, PO and OSA), one of which (the OSA) makes a controlled re-entry over Orenburg for recovery, would make you think the remaining two debris pieces are these two other modules, the OA and PO. However, it is generally believed that the AO/PO combination provides the retrofire necessary for the OSA de-orbit and hence goes down with the OSA.  It is believed that the OSA module itself has no retrofire capacity (if it would have, it would separate from the other modules and then fire its own retrorocket, leaving the other two modules in orbit).

So analysts have proposed that the debris pieces instead are satellite parts like solar panels (which are 6 meters in lenght each)  and antennae shed somewhat before the OSA re-entry. That idea is more likely yet in itself not entirely unproblematic either. In the case of Kosmos 2410 in 2005, the debris pieces were generated at least 16 hours (if not more) before the OSA reentry. It seems somewhat unlikely that you shed power sources (solar panels) and communication equipment (antennae) so many hours before the OSA re-entry.

The observations from the USA on September 2-3 suggest a seizable object. This is not small debris, but definitely a large object.

So that part of the story remains a bit of a mystery.

UPDATE 1, 11 Sep 2014, 15:00 UT:

Dr Bill Cooke of the Meteoroid Environments Office at NASA's Marshall Space Flight Center informed me (and this information is posted here with his kind permission) that their camera systems catched the event from New Mexico. From the data they determined that the object entered with a speed of  7.69 +/- 0.07 km/s.

That is too slow for an object in heliocentric orbit (a meteor), but the typical speed of an object entering from Low Earth Orbit. Basically, this confirms that the event over the USA was the decay from orbit of (a part of) an artificial satellite.

I thank Dr Cooke for communicating this vital piece of information.

UPDATE 2, 15 Sep 2014, 15:30 UT: 

Ted Molczan has published an excellent analysis into the area-to-mass ratio's of past Kobalt-M debris, which compares favourable to the area-to-mass ratio needed for Kosmos 2465 debris shed at OSA separation to decay over the US at 4:33 UT.

Acknowledgement: I thank Ted Molczan, Jon Mikkel and Jonathan McDowell for the exchange of ideas. Igor Lissov provided valuable data on the Kazakhstan sightings and earlier sightings of Kobalt-M OSA re-entries from that region on Seesat.

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Friday, July 18, 2014

SBIRS, SIGINT and the MH17 tragedy (updated)

Yesterday 17 July near 14:15 UT, 298 people including at least 173 189 192 of my countrymen perished when Malaysian Airlines flight MH17 on its way from Amsterdam to Kuala Lumpur crashed over the eastern Ukraine, reportedly after being hit by a missile.

This is a terrible tragedy. Among the victims are complete families, including children. It is the start of the holidays in the Netherlands, and the flight carried many Dutch families on their way to their holiday destinations in southeast Asia. My thoughts are with these highly stricken families.

For me personally, it is an unnerving fact that I was about to fly the same route from Amsterdam to southeast Asia only a few days later.

In the wake of the incident, accusations fly between the Ukrainians, pro-Russian separatists and Russians, all accusing each other of being responsible for this tragedy. At the moment it is difficult to say which bits of information floating around are true and which are false. I strongly suspect that the current suspicion against Russian-backed separatists will hold though. Some less ambiguous evidence (e.g. the location of the crash, which is close to the locations where separatists earlier downed two other (military) aircraft) certainly seem to suggest this. But we will see: at the moment, nothing is certain.

Of interest to this blog, is that US Intelligence officials have confirmed that the aircraft was hit by a surface-to-air missile, according to several US media. Senior US officials appear to have told CNN that they detected a radar signal from a surface-to-air missile system being turned on right before the crash, and that they also detected a 'heat signature' at the time the aircraft was lost.

If the CNN report is correct, it is highly likely that the 'heat signature' detection was a space-born detection by the SBIRS system of infra-red early warning satellites. I have written about this satellite system before, in the context of that other recent tragedy with a Malaysian Airlines flight, the disappeared flight MH370.

click image to enlarge

Three of the four SBIRS satellites, SBIRS GEO 1 (2011-019A) and SBIRS GEO 2 (2013-011A) in geostationary orbit and USA 184 (2006-027A) in HEO, had coverage of the area where MH17 went down at the time this happened (17 July 14:15 GMT, see image above).

SBIRS and SIGINT platform USA 184, imaged on 20 March 2014

SBIRS GEO 2 imaged on 20 June 2014

It is possible that the quoted detection of a missile radar tracking system activation around the time of the disaster was done by satellites too. Several SIGINT and ELINT satellites cover this area, including various MENTOR (ORION) satellites and one MERCURY satellite in GEO, and USA 184, which is both a TRUMPET-FO SIGINT satellite and a SBIRS platform, in HEO. That these SIGINT satellites amongst others serve to detect and monitor signals from military radar and missile systems, is known. Given the interest of the USA and NATO in closely watching military developments in the Ukraine conflict, it is almost certain that some of these are targetting the area.

The question is, whether these satellites can help pinpoint the location from where the missile was launched, and hence provide an indication of who did it (Ukrainian forces, separatist militia, or the Russians).

I suspect they can. If the SIGINT detections were indeed done by satellites, it is known that the US recently made large progress in geolocating the origin of detected signals. In a speech from September 2010 available on the NRO website, NRO director Bruce Carlson specifically remarked on the NRO's increasing capability to geolocate using SIGINT:

"I will tell you that just in the last 24 months, we’ve improved the accuracy of geo-location by nearly an order of magnitude, and we’re going to continue to do that and bring it down. We’re getting to the point where here very, very shortly, within the very near term, we will be able to target using signals intelligence". 

If they indeed have a SIGINT detection of the missile's radar system (and the CNN quote seems to say that), the character of the signature might yield information on what missile system was used (i.e. if it was indeed an SA-17/BUK).

Likewise, and although as far as I know no exact public information is available on the accuracy of this kind of detections (update: but see the update at the end of this post!) , I suspect that the  'heat signature' detections of the missile launch,  if indeed SBIRS infra-red detections, are also accurate enough to geolocate the launch site (and whether that is in Ukranian held, or separatist held territory).

A SBIRS platform has two sensors: one in staring mode, and one in scanning mode. The staring scanning mode sensor watches for heat signatures over a wide semi-global area. The scanning staring sensor targets specific regions, and when the staring scanning sensor detects a signature, the scanning staring sensor (at least according to some sources) can be employed to further pinpoint and track this event (more sources amongst others here, here and here). The goal of SBIRS reportedly is to be able to track launches, pinpoint launch sites and accurately predict potential target locations from the tracking data. That needs quite accurate tracking.

Update 19/07/2014: Daniel Fischer managed to dig up this unclassified presentation from 2006, which shows that SBIRS indeed can detect SAM. Pages 2 and 3 mention the capability to pinpoint the launch location. 
Rainer Kresken has raised the legitimate question of the cloud cover present at the time of the shootdown. Water vapour obscures Infra Red, which means the cloud cover might have blocked detection of the initial launch phase of the SAM. The SIGINT detection of the missile system radar does not suffer from this problem.

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Wednesday, July 09, 2014

A bounty of GEO satellites on June 21

The night of June 21-22 was clear, and as I had trouble sleeping, I decided to take the short bicycle trip to my secondary site, Cospar 4355. This site is located in the polder only just outside of town, but the sky is better there than at my regular site 4353, which is in the town center (the secondary site is about 2 km south of my regular site). As a result, I can use twice as long exposures, which means I can image fainter GEO satellites than from my regular site. The site, being in a polder, also has less horizon obstruction. Below is a panorama of the site, split up in two parts, each slightly larger than 180 degrees. Azimuth directions are indicated.

Panoramic view at Cospar 4355

I took some 54 picture (20 second exposures with a Canon EOS 60D + SamYang 1.4/85mm at 800 ISO) over the course of an hour. My main focus was on approximately 20-30 degree (1-2 camera fields) wide equatorial areas near azimuth 120-130 deg, 160 deg and 200 deg.

I captured a nice batch of objects: 17 classified objects, two Unknowns (initially four but two got ID-ed as classifieds) and A LOT of unclassified objects. The image in the top of this post shows an only 2.7 degree wide stretch of one image, and look how many objects are already in it.
One of the objects in the image, the defunct Russian military comsat Raduga 1-M1/Kosmos 2434 (2007-058A) was flaring repeatedly in subsequent images (compare also the two images in the top of this post).

The images below show two other swaths of sky only a few degrees wide. Various commercial GEO sats are visible, as well as two old Ariane r/b, of which several were captured this night:

click image to enlarge

It also shows  the British military communications satellite Skynet 5B (2007-0056B).

One of the classified objects captured this night was AEHF 2 (USA 235, 2012-019A), part the new military communications satellite constellation that is gradually replacing the Milsat system. Another object imaged was the SBIRS GEO 2 (2013-011A) satellite, part of the new infra-red Early Warning constellation that is replacing the DSP constellation.

click images to enlarge

The lower of the two images above (it is slightly blurry because it is the edge of the image) also shows one of the initial UNID's of that night, "UNID 2", one that Cees and Ted later identified as the classified Italian military communications satellite Sicral 1 (2001-005A), which has recently been moved to 22 E.

Cees also managed to identify another UNID I imaged that night, "UNID 3":

click image to enlarge

It is the object we amateur trackers designate as Unknown 130929 (2013-772A), an object in a Molniya orbit which was last seen 132 days before my observations (i.e. we temporarily "lost" it). It was over West Africa at an altitude of 1270 km at the time of observation, moving away from perigee:

Two other UNID's of this night remain to be identified. One of these ("UNID 1") appears to be in GTO: the other one ("UNID 4") appears to be in LEO and was very faint.

The image below shows two classified objects (plus several commercial geosats), both US Military communications satellites: USA 236 (2012-033A) and WGS 3 (2009-068A). WGS 3 is the third satellite in the Wideband Global Satcom constellation. USA 236 is a geostationary SDS data relay satellite. It is believed that they notably relay imagery of IMINT satellites in LEO, for example optical imageryby  KH-11 Keyhole/CRYSTAL and radar imagery by Lacrosse and FIA.

click image to enlarge

Mentor 4 and Thuraya 2 change of configuration

A change is occurring in the configuration of Mentor 4 (USA 202, 2009-001A), a huge Mentor /ORION SIGINT satellite, and the commercial communications satellite Thuraya 2. For over 3 years, Mentor 4 was stationed (as seen from my observing location) slightly south of Thuraya 2. On my June 21 imagery, it has moved to slightly North of Thuraya 2. Compare the top image from last June 21 with some images shot in previous years:

21 June 2014:

8 December 2010:

18 November 2012:

29 December 2013:
click images to enlarge

(The first image also shows the still unidentified UNID 1, likely in GTO, and  a classified r/b from another Mentor/ORION launch, Mentor 3 r/b (2003-041B)).

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Tuesday, June 24, 2014

ISS transiting the Sun

click image to enlarge

Yesterday (June 23, 2014) near 16:15:29 UT (18:15:29 CEST), the International Space Station (ISS) passed in front of the solar disc as seen from my observing location in downtown Leiden. As can be seen in the picture above, the transit was nearly central (the calculated central line was 600 meter to the north of me). The whole event had a duration of about 1.5 seconds, during which 9 photographs captured the Space Station silhoueted against the sun. The images were made with my Canon EOS 60D through my Celestron C6 (15 cm Schmidt-Cassegrain), fitted with a Solar Screen filter and an F/6.3 focal reducer. The sun was low in the sky at an elevation of 31.8 degrees due West. The inset is a stack of the 5 best ISS silhouets.

The images are not perfectly sharp, which is due to air turbulence (even at 1/4000 second) and the simple fact that I find it quite hard to focus the telescope properly on the sun, certainly when it is almost featureless. Nevertheless, I am satisfied with this image.

I knew of the transit because I subscribe to alerts from CalSky for this kind of phenomena. In preparation for the actual observation, I download the latest ISS elements from Space-Track a few hours before the event, and load them into Guide to fine-tune the transit time and the path over the solar (or lunar) disc. Starting about 1 second before the calculated commencement of the transit, I start a rapid burst series of images at 5.7 images/second.

click images to enlarge

Above are two pictures of the setup used. The filter mount is homebrew and quite simple (from thin cartboard). The filter itself is Solar Screen, a mylar filter with a double thin aluminium filter coating. Using such a filter makes it safe to look at the sun (NEVER look at the sun without a proper filter!).

In order to be able to see anything on the camera LCD screen in the bright sunlight, I put a towel over my head and the telescope back during focussing.

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Monday, June 23, 2014

[UPDATED] Three UNID's in GEO/GTO/HEO/MEO, SBIRS GEO 2, and Lacrosse 5 has manoeuvered

Updated 14:35 UT (Jun 23) to reflect that I found a third UNID on my imagery after writing the original post

click image to enlarge

Saturday/Sunday night 21/22 June was very clear. As I had some trouble getting to sleep, I decided to make use of it to do a survey of the GEO belt, from my secondary site Cospar 4355 which is in the polder just outside of town, some 10-15 minutes by bicycle. The sky is a bit darker there and I have a better view to low elevations. Using the 1.4/85mm Samyang lens, I can expose twice as long as I can from my regular town center site 4353. The downside: so many objects on the images to identify and measure....

This observing site, in a polder park with meadows and polder ditches, is very tranquile. A choir of frogs was chanting during my observations, and meadow birds were adding their voice too. As I was observing, a low blanket of ground fog started to form, with my camera on tripod popping up just above it.

Two Three UNID's

At the moment I am still slowly working myself through the 54 images taken, identifying objects, but I can already report that I captured two three UNID objects (for positions on the 3rd see here), two in GTO/GEO and one in MEOor HEO. They are not in the Space-Track catalogue nor in our classified catalogue.

click image to enlarge

UNID 1 was observed as a small trail on several images taken between 23:05:32 and 23:23:32 UT (June 21). The 15 second image above shows it near the SIGINT satellite Mentor 4 (2009-001A) and is the first image that captured it. It looks like something in GTO and a very cautious orbit fit to this short 18 minute observation arc indeed suggests a GTO-like, roughly 13160 x 36945 km, 12.8 degree inclined orbit with a period of ~1.6 revolutions per day:

UNID 1                                               13160 x 36945 km
1 00000U 00000X   14172.96808160 0.00000000  00000-0  00000+0 0    05
2 00000  12.7577 311.8608 3783132 187.8049 143.4679  1.55784798    00

click image to enlarge

UNID 2 was detected on only two 20 second images taken half a minute apart. It is less trail like (see image above), but slowly moving south when the measurements on the two images are combined. It is either in a somewhat inclined GEO orbit or a GTO object near apogee.

The image above also shows SBIRS GEO 2 (2013-011A), a classified geostationary SBIRS satellite (an Early Warning satellite looking for missile launches in Infra-Red). In addition, an old Russian r/b and a Russian military GLONASS (the Russian equivalent of GPS) satellite are visible. Star trails are slightly blurry because the FOV represents a detail near the edge of the image.

click image to enlarge

UNID 3 was detected close to alpha Serpens in only two 20 second images taken 1 minute apart.  It is clearly trailing. The positions fit either a circular MEO orbit, or a HEO orbit (the observation arc is too short to discriminate). Above, the two images that captured it are shown.

Lacrosse 5 appears to have manoeuvered

The same image that captured UNID 1 also captured the military Radar satellite Lacrosse 5 (2005-016A, see image in top of this post), just as it was emerging from Earth shadow. It was about 54 seconds late relative to 8-day-old elements. That is a lot for only 8 day old elements. Hence it appears to have manoeuvered somewhere in the past few days.

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Tuesday, June 17, 2014

Prowler flaring

click image to enlarge

I have written on the enigmatic Prowler satellite (1990-097E) before. I periodically observe it using a 'remote' telescope (usually the 0.61-meter Cassegrain of SSON, MPC G68).

On 2014 June 10 I captured it briefly flaring - I had not observed that before, though other observers had. The brief flare can be seen near the edge of the image (the trail runs out of the FOV) in the lowermost of the two images above.

Approximate positions of this flare:

- begin RA 17 25 24.73 DEC -20 49 41.7
- maximum RA 17 25 26.15 DEC -20 49 45.2
- end RA 17 25 27.36 DEC -20 49 45.6

Extrapolation from the measured timed positions above, gives the following approximate times for the flare:

- begin 09:25:23.9 (UT, 10 June)
- maximum 09:25:25.3 (UT, 10 June)
- end 09:25:26.5 (UT, 10 June)

Apart from these short flashes, observers report a much slower brightness variation. Indeed, I had suspected such from my own observations, as the trail brightness widely varies (between bright and completely invisible) between different image sessions. On May 27 for example, I also tried to image Prowler using the same 0.61-meter telescope, but it was invisible.

As Allen Thomson remarked, part of this brightness behaviour might be due to Prowler's former stealth characteristics.


Tuesday, June 10, 2014

Tracking USA 161

click image to enlarge

I am a bit behind with posting the image above taken a week ago, on 3 June 2014 . It shows the KH-11 Keyhole/CRYSTAL optical reconnaissance satellite USA 161 (2001-044A), which was recently recovered.

With new observations including mine, the orbit is now getting better defined. During the winter blackout, the orbit of the satellite appears to have been further circularized to a 389 x 391 km orbit, by a small perigee rise.

In the image above, another object is also visible: a Falcon 9 r/b, 2010-066K, at over 5000 km altitude at that time.

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Sunday, June 08, 2014

Telescopically imaging the ISS (plus some deep-sky)

So far, my satellite imaging has always been done with a DSLR and normal camera lenses and were essentially 'wide field'. The largest focal length I so far used was 180 mm.

click images to enlarge

Last week I have experimented with telescopic imaging of the International Space Station (ISS), using my Celestron C6 (15 cm F/10 Schmidt-Cassegrain). Above is the best image, shot 6 June 2014 at 22:07:13 UT as the ISS was zipping past beta Bootes. It is a single image from the series, taken at 1/4000th second at ISO 800.

I kept it simple: I did not actively track the ISS, but looked for points where it passed close to a reasonably bright star, and then pointed the telescope to that position. As the ISS passed that point, I did a rapid burst series of images, a few of them which then showed the ISS zipping through the field. I used 1/4000th second exposures.

That technique is actually enough to get some decent pictures. Later, I will probably experiment with active tracking using computer guidance of the mount, and see whether video might yield more that photography (one drawback of video is a lower resolution, so a need to work with Barlows).

Having the telescope out anyway, I made some deep-sky images too the last two nights, of some bright summer sky icons. Again, I kept it simple. As I work from a town center, and a location where I cannot see the Pole star due to obstruction by a building (which hampers telescope alignment), I kept exposure times short, to 10-15 seconds. Then I stacked large numbers of images.

click image to enlarge

The above image of M27, the Dumbbell nebula, a planetary nebula in Vulpecula, is my favourite. It is a stack of 57 images of 15 seconds exposure each at 2000 ISO. The faintest stars on this image are near mag. +16.8, which is not bad with short exposures from a town center.

click image to enlarge

Another iconic planetary nebula in the summer sky is M57, the Ring nebula in Lyra. The image is on the same scale as that of M27 above. This image is the result of stacking 60 images of 10 seconds exposure (the scope didn't track that well that night) at 1600 ISO.

click image to enlarge

The final image shows globular cluster M13 in Hercules. It is a stack of 57 images of 15 seconds exposure, taken at 2000 ISO.

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Sunday, June 01, 2014

Sorting out the confusion: USA 161 and IGS 8R

Okay, so yesterday considerable confusion arose about the current orbit of USA 161 (see previous post). This was due to the (luckily shortlived) confusion between two objects: the real USA 161, and a Japanese spysat that was briefly mistaken by me for USA 161.

The object which I photographed during the night of May 30-31 and which Björn Gimmle photographed from Sweden on April 22, turned out to be not USA 161 but, as Cees Bassa pointed out, another classified object we had "lost" in the winter blackout: IGS 8R (2013-002C), a Japanese radar imaging satellite launched early 2013.

So the image below actually shows IGS 8R flaring brightly, not USA 161 as I initially thought:

click image to enlarge

Luckily, Russell Eberst in Scotland observed the real USA 161 on June 1. Together with the observation by Leo on May 23, this means we do have an idea of the current orbit of USA 161 now, although further refinement through more observations is necessary. What is clear, is that USA 161 still is in the same orbital plane it was in when we lost it in August 2013. It's RAAN difference with the primary East plane KH-11 USA 224 is still 20 degrees, and it's orbit is sun-synchronous and about 385 x 393 km (these are approximate values which are subject to change, as the current orbit is preliminary and needs some refinement with more observations). The current KH11 Keyhole/CRYSTAL constellation now looks like this:

The short-lived confusion of yesterday could arise because both objects (IGS 8R and USA 161) currently move in a similar orbital plane. This can be seen in the image below, where the IGS 8R orbit is yellow and the USA 161 orbit is light grey:

This is the kind of confusion that can arise when multiple objects who's orbit have not been recently updated, move in a similar orbital plane. It does not only happen to us amateur trackers: even the professionals at JSpOC sometimes confuse objects.

Actually, this situation ended positive with a double recovery: that of USA 161, and that of IGS 8R.

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Saturday, May 31, 2014

[AGAIN UPDATED] USA 161 recovered (?) - and new ideas on changes in the KH system

CORRECTION 1 June 2014: The object I observed on May 31 turns out to be NOT the KH USA 161, but one of the IGS objects, IGS 8R (2013-002C) which we had 'lost' in the winter blackout, just like USA 161. Their orbital planes happen to be very close (with a few tenths of a degree in inclination and a few degrees in RAAN) at the moment.

This renders the whole story below incorrect and hence moot.

Luckily, Russell Eberst did observe the real USA 161 last night (June 1) and his observations fit with Leo's observations from May 23. More in a new post later. (this new post is up now here)

ML, 01/06/2014

- STOP PRESS - (31 May 2014, 19:00 UT). Okay. Cees Bassa thinks last night's object is not USA 161. See here. So read the story below with caution: the jury is still out on all this.

Although it all was/is a bit confusing, it appears USA 166 (2001-044A), the secondary East plane KH-11 Keyhole/CRYSTAL has finally been recovered. [UPDATE: OR PERHAPS NOT???]. It had not been positively observed since August 2013 and over the past half year had been hiding in the northern hemisphere winter blackout.

USA 161 ?. IGS 8R last night
(click image to enlarge)

Initially, Leo Barhorst in Almere (NL) appeared to have recovered it on May 23. However, his observed object now turns out to not have been USA 161 but an unidentified other object.

Last night it was clear, after a very rainy week. Suffering from a bout of insomnia, I took advantage of the clear skies by conducting a 30 minute plane search, from 01:00 UT to 01:31 UT (May 31), using the EF 2.0/35 mm wide angle lens.

Just as I was about to abandon the effort at 01:30 UT, a bright and fast satellite appeared with a direction that was correct for USA 161 in a generally correct area of the sky. I managed to capture it on two images, the second one of which is depicted above. The object was about mag +2 when I first visually picked it up, and then becoming brighter as it produced a slow flare to mag -2 near 01:30:27 UTC. The image above shows the slow flare moment. It moved fast, producing long trails on the 10 second images with the 35 mm wide angle, so it evidently was near perigee.

The object could not be matched to any known object, but did appear to move in the general secondary East orbital plane of the KH-11. Visually, the slow bright flare it showed was quite typical for the KH-11 too. So I was (and am) fairly certain it is USA 161. Or not? Problem was, my observation was difficult to match with Leo's observation a week earlier...

After I reported my observations, Ted Molczan next managed to positively match my object to a UNID observation by Björn Gimmle in Sweden on April 22 (so over a month earlier), proceeding to fit a very reasonable orbit. The suggestion of this all is, that Leo's object from May 23 was something else, as it does not fit well with the other observations.

The preliminary orbit calculated by Ted, which needs to be refined by further observations, suggests that USA 161 made a manoeuvre into a (compared to the orbit it was last seen in in 2013) slightly higher orbit of 411 x 425 km, with the orbital inclination changed by half a degree to 97.52 degrees. This is the same orbital inclination as USA 129 (1996-072A), the former secondary West plane KH which we have recently "lost" and which is suspected to have been de-orbitted, was orbiting in.

Like the drifting secondary West plane KH USA 186 (2005-042A, see several previous posts on this blog for a discussion), USA 161 is no longer sun-synchronous as a result of this manoeuvre, and hence in what appears to be a plane transfer orbit. Its distance in RAAN relative to the primary East plane KH-11, USA 224 (2011-002A), has increased and will keep increasing steadily until it makes a corrective manoeuvre (which I suspect will happen near June 12, see below).

The orbital constellation for May 31 looks like this:

(image removed)
click image to enlarge

The current situation is that the two new primary plane objects, USA 224 and USA 245, are keeping a more or less steady plane distance (in terms of RAAN) of 48.5 degrees. The two (older) secondary plane satellites, USA 186 and USA 161 however have now both lost sun-synchronicity, and are both drifting outwards with respect to the orbital planes of their corresponding primary plane satellite.

Frequent readers of this blog will remember that I initially expected USA 186 to manoeuvre back into a non-drifting sun-synchronous orbit when the RAAN difference with USA 245 was 10 degrees, early February. That didn't happen. As a secondary option, I then thought it would manoeuvre when the difference was 20 degrees, early May. That didn't happen either. I then was at a loss as to what "they" were planning to do with USA 186.

Now USA 161 has been recovered and turns out to have been manoeuvered into a drifting plane-changing orbit as well, just like USA 186, I am getting a possible idea again about what they might intend. Please note: I have been wrong twice before, so my track-record in these kind of predictions is not quite good :-p

Nevertheless: assuming that symmetry is what is being aimed for, I think both objects (USA 186 and USA 161) will manoeuvre back into a non-drifting, sun-synchronous orbit on or near June 10 to June 12.

On May 31 the RAAN difference between USA 245 (primary West) and USA 186 (drifting secondary West) was 23.0 degrees. The RAAN difference between USA 224 (primary East) and USA 161 (drifting secondary East) was 23.7 degrees. Their rate of drift is different: it is -0.11 degrees/day for USA 186 and +0.056 degrees/day for USA 161 (i.e., USA 186 is drifting twice as fast as USA 161). These differential drift rates mean that at some point in time, both satellites will reach a matching value in RAAN difference with their primary partner, at similar RAAN distances from their primary partner on the same day. This is depicted in the diagram below:

(image removed)
click diagram to enlarge

What can be seen from the diagram, is that this moment will occur in about 10-12 days from now, near June 10-12. On June 12, both satellites (USA 186 and USA 161) will reach a matching difference in RAAN of 23.3 degrees with their primary partners USA 245 and USA 224. Interestingly, this value is very close to 0.5 times the RAAN difference between the primary plane satellites, USA 224 and USA 245 which are 48.5 degrees apart in RAAN.

But please be advised: until now, I was wrong each time I thought I could make sense of it....

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Wednesday, May 21, 2014

USA 224 recovered, USA 186 still drifting, and looking for GPS IIF-6 20 minutes after launch

For various reasons, I am a bit late in keeping the reader up to what is happening to the KH-11 Keyhole/CRYSTAL system of optical reconnaissance satellites.

USA 186 (2005-042A), the secondary West plane KH-11, is still in a non sun-synchronous orbit and hence still drifting westwards. It is drifting for over half a year now. The difference in RAAN with USA 245, the primary West plane KH-11, is now over 20 degrees (21.8 degrees on May 19th). I am very curious as to when the drifting will stop, if ever. If it continues to drift for many weeks to come, we should contemplate whether perhaps the satellite is "dead", i.e. has lost manoeuverability. Problem is that NW European observers temporarily have lost visibility of the satellite, due to the current short nights. Tracking all comes down now to observers in the US and southern Europe.

Meanwhile, Russell Eberst in Scotland recovered USA 224 (2011-002A), the primary East plane KH-11, on May 9th. It is in a 260 x 1006 km orbit, which means it has slightly lowered its apogee. Before the winter blackout it was in a 258 x 1023 km orbit. The difference in RAAN with USA 245, the primary West plane KH-11, is now 48.5 degrees.

My own first observation of USA 224 was in the night of May 16-17. The image below shows it crossing through Corona borealis:

click image to enlarge

USA 161 (2001-044A), the secondary East plane KH-11, has still not emerged out of the winter blackout. Meanwhile, USA 129 (1996-072A) has gone missing since April 24 (see a previous post). There is a good chance it has been de-orbitted.

The current KH-11 constellation now looks like this (where the current orbital configuration of USA 161, in red, is uncertain, and USA 129 left out as it is no longer in its old orbit, and presumed de-orbitted):

click images to enlarge

In the early morning of May 17 (evening of May 16 in the US) and after a one day delay due to bad weather, a new GPS satellite, GPS II-F6 was launched from Cape Canaveral on a Delta IV rocket. It would pass over the Netherlands some 20 minutes after launch, still ascending and still attached to the 2nd stage. A number of search orbit had been published, but it looks like none of these was very accurate. I visually observed a bright UNID near 00:24:00 UT (May 17) moving just a few degrees to the 'right' of Altair on a trajectory parallel to the predicted ones but some 20 degrees cross-track in a southern direction. It was already descending over the roof when I picked it up, so I had no time to snap a picture alas. It did not match any known object so I am quite confident it was GPS II F-6 on its way to orbit. It was bright, about mag +1 to 0.

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Monday, May 05, 2014

KH-11 USA 129 is missing, USA 186 has still not manoeuvered

USA 129 (96-072A), the oldest of the KH-11 Keyhole/CRYSTAL/KENNAN optical reconnaisance satellites, has gone missing. The last observers to see it were me on April 22 and Russel Eberst on April 24. The photo below shows one of my images from April 22, with USA 129 passing near Castor and Pollux:

click image to enlarge

Somewhere between that date and May 1, when various observers noted it missing, it disappeared.

There is a possibility that it has been de-orbitted, as it is over 17.5 years old now and appears to be 'redundant' after the launch of USA 245 and plane move of USA 186 (see various earlier posts on this blog). On the other hand, we should be cautious and not too hasty: in the recent past (Feb 2014) we erroneously wrote USA 129's eulogy before, and it turned out it had just manoeuvered. Maybe it did this time as well. A dedicated plane watch I did in the evening of 3 May between 20:41 -21:05 UT yielded nothing.

Meanwhile, we had expected USA 186 (2005-042A) to manoeuvre early May. But up to yesterday May 4th it hasn't. Maybe it will do in the coming days. On May 1st the difference in RAAN with the main West plane KH, USA 245, was 19.8 degrees. At a drift rate of 0.11 degrees/day, it reached 20 degrees the past weekend. If it hasn't manoeuvered by the end of the coming week, it will become interesting. Unfortunately, it is disappearing in evening twilight for my location these days.

The image below shows USA 186 crossing Canis minor in deep evening twilight of May 2nd:

click image to enlarge

I imaged USA 245 (2013-043A), the current main West plane KH-11, last Saturday evening. In evening twilight, it was visible in the same camera field with FIA Radar 1 (2010-046A):

click image to enlarge

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