NROL-71: an enigmatic launch [UPDATED]

(this post on NROL-71 is belated, as I was in hospital around the original launch date. Luckily, launch got postponed)

click map to enlarge

If nothing ontowards happens, the National Reconnaissance Office (NRO) will launch NROL-71, a Delta IV-Heavy with a classified payload, from Vandenberg SLC-6 on 19 December 2018 (18 December local time). [edit:] after the December 19 launch was scrubbed, a new launch attempt will take place on December 20 (December 19 local time in the USA). The December 20 launch was scrubbed as well due to a hydrogen leak in one of the boosters. A provisional new launch date is 21 December 2018 (December 20 local time in the USA) at 1:31 UT.

The new launch date will not be before 30 December 2018.

The launch was postponed three times. Originally to be launched on December 8, a communications problem aborted that launch. A renewed launch attempt the next day, was aborted only 7.5 seconds before lift-off because of a technical issue (see the video below).




A new launch attempt will take place on 19 December 2018 at 1:57 UT. As weather prospects at the moment do not look particularly good for that date, it is possible that the launch will see even further postponement. [edit:] This assessment turned out to be right: the launch was postponed due to high altitude winds. A new launch date has been set for 20 December 2018 at 1:44 UT. The December 20 launch was also aborted, due to a hydrogen leak in one of the boosters. A provisional new launch date has been set for 21 December (20 December local time in the USA) at 1:31 UT. The new launch date will not be before 30 December 2018.

NROL-71 is an odd launch. When the Maritime Broadcast Warnings for the launch came out and revealed the launch hazard areas, they contained a big surprise. The general expectation among analysts was that NROL-71 was the first of the Block V new generation KH-11 ADVANCED CRYSTAL electro-optical reconnaissance satellites. As such we expected it to go in a sun-synchronous, 97.9 degree inclined, 265 x 1000 km orbit.

But the Maritime Broadcast Warnings suggest this is NOT the case. The hazard areas are incompatible with such a sun-synchronous polar orbit. Instead, they point to a (non-sunsynchronous!) 74-75 degree inclined orbit. Not what you expect for an optical reconnaissance satellite!

The map below shows the three hazard zones. Two are directly downrange from the launch site, where the strap-on boosters and first stage splash down. The third area is the upper stage deorbit area (which is remarkably small in size), located northeast of Hawaii, with deorbit occuring near the end of the first revolution (as usual).

click map to enlarge

The trajectory depicted by the dashed line on the map is for a 74-degree inclined, 265 x 455 km orbit. Higher inclined orbits would miss the downrange splashdown zones and the upper stage deorbit area.

Ted Molczan has pointed out that the shift in launch time with each launch delay, points to a specific orbital plane and a specific aim for the rate of precession of the RAAN of -2.27 deg/day.

This is over twice as fast as the RAAN precession of the KH-11 currently in orbit (0.98 deg/day, i.e. sun-synchronous).

This value for the RAAN precession apparently aimed for, puts further constraints on the orbit as in combination with the 74-degree inclination deduced from the location of the Launch Hazard areas it points to a semi-major axis of about 6735 km.

Going from the notion of KH-11-like orbital altitudes, the current typical KH-11 perigee near 265 km would then result in an apogee near 455 km. This is somewhat similar to the orbital altitude of the oldest of the KH-11 on orbit, USA 186 in the secondary West plane, which was in a 262 x 443 km orbit when we last observed it early October (it currently is invisible due to the winter blackout). This apogee would be much lower than that of the two KH-11 payloads in the primary planes, which have apogee near 1000 km, i.e. twice as high, another deviation from expectations. Normally, KH-11 are launched into a primary plane and about 265 x 1000 km orbit, and only after some years, when the payload is moved to a secondary plane (and a new payload is launched into the primary plane), is apogee lowered to ~450 km (see an earlier post here).

So, if NROL-71 is a new electro-optical reconnaissance satellite in the KH-11 series, it represents a serious deviation from past KH-11 missions. The apparent abandoning of a sun-synchronous polar orbit, is surprising, as such orbits are almost synonymous with Earth Reconnaissance. The "why" of a 74-degree orbit is mystifying too. If it does go into a 74-degree inclined orbit, it doesn't seem to be a "Multi-Sun-Synchonous-Orbit".

Alternatives have been proposed. Ted Molczan has for example suggested that, perhaps, NROL-71 could be a reincarnation of the Misty stealth satellites, warning that the unexpected orbital inclination for NROL-71 might not be the only surprise.

I myself was struck by the fact that 74-degree orbital inclination is the prograde complementary of the retrograde 106 degree inclination of the FIA Radar/TOPAZ 6 payload (USA 281,  2018-005A) launched early this year: note that 180-106 = 74. FIA Radar 6 was the first in a new block of TOPAZ radar payloads, just like NROL-71 appears to be the first in a new block of  'something'.

The previous four FIA Radars, launched into 123-degree inclined orbits, were the retrograde complementary in inclination of the prograde 57-degree Lacrosse 5 orbit, another radar satellite. The complementary character of 106-degree versus 74-degree for NROL-71, could perhaps point to NROL-71 being a Lacrosse Follow-On, as a complementary to the newest FIA block.

If NROL-71 is a Lacrosse Follow-On, its orbital altitude and brightness behavious might yield clues: Lacrosse 5 has shown a very distinct brightness behaviour.

It will be very interesting to chase this launch. If launch occurs on 19 December near 1:57 UT and weather cooperates, Europe will have visible evening twilight passes in the first few days.

Below are a couple of search orbits. All are for an assumed 74-degree orbital inclination and launch on 19 December at 1:57 UT. The first three are for KH-11 like orbital altitudes. The fourth is for a Lacrosse-like orbital altitude.

Orbit #70003 fits the hazard areas from the Maritime Broadcast Warnings best.

[EDIT: new updated search orbits below, for the new launch date, 19 Dec 20918 1:44 UT] 

[EDIT: new updated search orbits below, for the new launch date, 21 Dec 2018 1:31 UT]



NROL-71                                                 265 x 1000 km
1 70001U 18999A   18355.06319444  .00000000  00000-0  00000-0 0    00
2 70001 074.0000 184.7636 0524203 155.2439 326.4145 14.78994708    03

NROL-71                                                  265 x 500 km
1 70002U 18999A   18355.06319444  .00000000  00000-0  00000-0 0    01
2 70002 074.0000 184.7636 0173800 155.2439 324.5345 15.61785606    06

NROL-71                                                  265 x 455 km
1 70003U 18999A   18355.06319444  .00000000  00000-0  00000-0 0    02
2 70003 074.0000 184.7636 0140989 155.2439 324.3567 15.69614809    07

NROL-71                                                  715 x 725 km
1 70004U 18999A   18355.06319444  .00000000  00000-0  00000-0 0    03
2 70004 074.0000 184.8196 0007044 155.2265 327.0336 14.51731413    06



Note that deviations of many minutes in pass time and several degrees deviation in cross-track are possible on all four orbits, certainly several revolutions after launch.

SIGINT, IMINT and MH17

(this post continues discussions in earlier posts on possible classified space-based observations of the shootdown of Malaysian Airlines flight MH17 over the Ukraine in 2014)

My position paper written for the Dutch Parliament Foreign Affairs committee hearing of Jan 22 (see my previous post) has a strong focus on infra-red detections of a missile by SBIRS. There are however a few other relevant aspects of Space Based observations in connection to the MH17 disaster that I could not cover in the space available to me for that paper.

In this post, I will provide some brief additional information about:

1) potential roles for IMINT satellites;
2) the positions of SIGINT satellites.


Optical and radar IMINT

1. optical IMINT

Both (unclassified) commercial and (classified) military satellite systems for high-resolution optical imagery (Image Intelligence, IMINT) exist, and both sources will be discussed below.

Optical and radar imagery obtained in the hours before, as well as during the event, might be used to look for missile systems, both on the Ukrainian as well as separatist sides of the front, in a wide circle around the site of the shootdown. It could also be used to verify the reconstruction of the purported movements of a Russian BUK system published by citizen journalist team Bellingcat, a study which is not uncontested. The Bellingcat team places the BUK in certain places at certain times, and if space-based imagery (either military or commercial) for those locations and times exist they could perhaps verify these claims.

The US military has one classified system of optical satellites with a (much-) better-than-1-meter capability: the KH-11 IMPROVED CRYSTAL/Evolved Enhanced CRYSTAL (aka 'Keyhole' or 'KENNAN') which reportedly (and theoretically, from known 2.4 meter mirror size specs) have a resolution in the order of  10-20 cm.

Mid-2014 this system consisted of four satellites: USA 161, USA 186, USA 224 and USA 245. All of these have been discussed on this blog before and are tracked by our amateur network.

We have accurate tracking data on three of these, USA 161, USA 224 and USA 245 for the days around 17 July 2014 and hence can pinpoint when these potentially had the crash area in their sight to better than a minute. For USA 186, which was actively manoeuvering around that time and for which we have a gap in our coverage form June to August 2014, pass times are a bit less certain and constrained to about 20-30 minutes accuracy.

First, we can positively affirm that one of the KH-11, USA 161 (2001-044A) actually had the Ukraine in its potential view during the incident at 13:20 UT:

click images to enlarge

Please note well: this does however NOT mean that USA 161 delivered imagery of the event. A number of factors should be taken into account:

1. the cloud cover at that moment, which might hinder imagery;
2. the crash site is located quite in the perifery of the satellites footprint area;
3. these satellites do likely not make images continuously, but only if commanded to do so, for specific areas of interest;
4. there is the question of whether USA 161 was still operational at that time. It was the oldest of the on-orbit KH-11, being launched 14 years earlier. Only a few months later it was de-orbitted, so it was clearly at the end of its lifetime.

In addition to their KH-11 system, the US military hires space on commercial high resolution optical IMINT satellites from the US commercial firm Digitalglobe (the same firm that supplies Google Earth with satellite imagery).  

Digitalglobe operates a number of satellites with a better-than-1-meter capability: Geoeye-1 (0.4 meter resolution), and Worldview 1, 2 and 3 (0.25-0.50 meter resolution). Most of the satellite imagery that the US Department of Defense supplies to the press (when briefing on the military situation in e.g. North Korea, Syria and Libya) comes from these commercial satellites.

Imagery from these same Digitalglobe satellites is also available commercially, to any interested party with money. And in addition to DigitalGlobe, the European company Airbus Defense and Space also offers commercial high-resolution optical imagery from its SPOT and Pléiades satellites. Pléiades 1A and 1B offer a 0.5 meter resolution. SPOT 5 and 6 offer a 2.5-1.5 meter resolution.

Accurate orbital data from non-classified sources are available for all the commercial imagers for 17 July 2014. The satellites in question made several daylight passes over the area in the morning of July 17, 2014, between 8:00 and 10:00 GMT, i.e. during the 3 to 5 hours before the shootdown, a period when the skies were still less clouded.

This does not mean that they necessarily made imagery of course. Yet any imagery these commercial Digitalglobe and Airbus satellites did make on July 16, 17 and 18 have the advantage that they are not "classified", unlike the US military data, meaning that they could be used and published without diplomatic problems by the Dutch government in the Dutch criminal investigation into the disaster.

I would therefore expect the Dutch OM to either buy or subpoena all potential Digitalglobe and Airbus imagery from these dates. They can be used to reconstruct missile system positions in the area (both on the Ukrainian, the separatist and Russian sides) within range of the shootdown location, and they can be used to hunt for missile transports (see my earlier remarks about the Bellingcat claims). The Dutch Air Force has an imagery analysis unit that is well suited to help with such an analysis. Including imagery from the days before and after the incident as well is useful to look for differences between imagery of these respective dates.


2. Radar IMINT

The US military has two systems for high resolution radar IMINT: the Lacrosse (ONYX) system of which currently only one satellite, Lacrosse 5 (2005-016A) is left on-orbit, and the radar component of the Future Imagery Architecture (known as TOPAZ), consisting of three satellites: FIA Radar 1, 2 and 3 (2010-046A, 2012-014A and 2013-072A). These systems should be capable of providing imagery with sub-meter resolutions, and like optical imagery, they can be used to look for the presence of missile systems in the area. They have the added bonus that they are not hampered by cloud cover, unlike optical imagery.

Apart from the USA, the German military also operates a radar satellite system, the SAR-Lupe satellites. The French military likewise operates its own radar satellite system, the Hélios system. Japan operates the IGS system (which includes both optical and radar satellite versions).

All of these satellites made passes over the Ukraine at one time or another on July 17 2014, so all of them might have provided useful imagery.  FIA Radar 3 made a pass right over the area in question near 11:43 UT for example, some 1.5 hours before the tragedy. FIA Radar 2 made a pass over the area at 18:00 UT, 4.5 hours after the shootdown. These are just a few examples.

Given what was happening in the area around this time, and the strong concern of NATO and the EU about this, it is almost certain that imagery of the area was collected by these US, German and French satellite systems.


SIGINT

My position paper briefly mentions that a number of countries have space-based SIGINT (Signals Intelligence) capacities. This does not only concern capacities for (for example) the NSA to tap into your cellphone and satellite telephone conversations: another important strategic aspect of space-based SIGINT is the capacity to detect radar and telemetry signals from enemy weapons systems. Such detections allow identification of the used weapons system (each system has its own 'signature'). They also allow, according to remarks by the then NRO director Bruce Carlson in a speech from September 2010 at the National Space Symposium, geolocation of the source of this radar signal (in the case of MH17: geolocation of the Target Acquisition Radar of the launch unit).

The US military has a number of SIGINT systems in several types of orbits: Low Earth Orbit (LEO) below 1500 km which allows coverage of a few minutes during a pass over a target; and Highly Elliptical Orbit (HEO) and geosynchronous orbit (GEO), which allow to monitor targets for many hours (HEO) to continuously (GEO) from distances of 36 000+ km.

France has a number of SIGINT satellites in LEO. China no doubt has SIGINT satellites too, as does Russia. For the moment I will focus on the US systems. I must ad that I did check the French systems as well but none of the French systems (ESSAIM and Elisa, both in LEO) had sight of the Ukraine at that time.

The US systems, under the catch-all codename ORION, include the TRUMPET-FO which move in HEO. One of them is USA 184, mentioned before in the discussion of SBIRS as it has a piggyback SBIRS capacity in addition to its main SIGINT role.

There are also the big MENTOR satellites in GEO, plus two MERCURY satellites also in GEO, and the older VORTEX system. Of these systems, TRUMPET-FO, MENTOR and MERCURY are certainly still active based on their orbital behaviour.

The map below shows the positions of those satellites in this series for which we have enough tracking data to allow a reconstruction of their positions and footprints on 17 July 2014, 13:20 UT and which had the MH17 crash area within potential view:

click map to enlarge

Again: this does NOT necessarily mean that all of these satellites were actively monitoring the Ukraine at that time. Quite a number of them will have been tasked on the Middle East.

Yet, given the strong NATO interest in events in the Ukraine at that time, notably the rising concern about advanced surface-to-air missile systems following the shootdown of a Ukrainian Antonov-26 a few days earlier, I would be surprised if none of them monitored the Ukraine at all.


A clarification note on the position of USA 184 (SIGINT/SBIRS)

In my position paper written for the Dutch Parliament Foreign Affairs committee meeting coming Friday, I included this map with the positions of three SBIRS satellites with view on the Ukraine at that time:

click map to enlarge

I should point out here that there is some leeway in the exact position of USA 184, depending on whether it made a corrective manoeuvre to maintain its Mean Motion of about 2.00615 revolutions/day or not since the day we last observed it.

If it did, its position would be slightly more westward compared to the position depicted above, i.e. in a position just north of Scotland rather than above the Norwegian coast:

Let me be clear: this does NOT influence the conclusions of my position paper: the MH17 crash site in both variants is well within the field of view as seen from USA 184, i.e. the satellite could potentially provide both Infra-red and SIGINT detections. In the interest of accuracy, I thought I should however mention it here.


Acknowledgement -  I thank Mike McCants (USA) and Ted Molczan (Canada) for discussions about satellite positions, notably concerning USA 184.

[UPDATED] A post-analysis of the N-Korean launch window, and N-Korean Spooks on my weblog?

On December 12, North Korea surprised the Western world by successfully bringing its first independently confirmed satellite into orbit: Kwangmyongsong 3-2, a reportedly 100 kg cubesat. For images of the satellite and an analysis of its likely components, see here. The satellite was launched with an UNHA 3 rocket from Sohae Launch Centre in Cholsan.

The successful launch came as a surprise for two reasons. First, all previous North Korean satellite launch attempts abysmally failed (even if N-Korea claimed they were a success).

Second, North Korea had indicated days before the launch that the launch was to be postponed to late December, for technical reasons. This appears to have been a deliberate disinformation ploy by N-Korea. According to South Korean press sources, it appears they also tried to play a ruse on the Americans, by pretending to dismantle the rocket when US imaging satellites were overhead, and continuing launch preparations when they were not.




Analysing the time of launch and US satellite coverage of the launch site

Well then: did the North Koreans indeed try to evade US (and Japanese) satellite surveillance?

First, they would not have been able to evade detection of the launch itself by US infra-red early warning satellites such as the DSP satellites and SBIRS in geostationary and HEO orbit. Coverage by these satellites is continuous.

But that was probably not N-Korea's goal anyway. Their goal reportedly was to try to convince analysts of imagery from US imaging satellites (optical and radar) that the rocket was not yet complete at the launch site, and not yet ready to launch for a while. The aim was apparently to throw off US predictions about the "when" of the launch until the very moment of launch itself.

Their concern hence was with US and Japanese optical and radar imaging satellites such as the KH-12 Keyholes, Lacrosses, FIA and IGS. These imaging satellites move in LEO, and coverage is not continuous- not yet at least.

Indeed, the timing of the North Korean launch (00:49 UTC on December 12) is interesting. It coincides with the end of a one hour long interval with no coverage of the launch site by US or Japanese Low Earth Orbit imaging satellites.

By contrast, in the hours prior to and after this one-hour gap in coverage, such periods of non-coverage were much shorter (typically 10-15 minutes at best), as can be seen in the coverage analysis images below and the movie near the top of this post (movie, images and analysis made using JSatTrak).

click image to enlarge

As can be seen from the coverage analysis, this hour long interval between 23:45-00:45 UT really stands out compared to the hours before and after. The N-Koreans launched right at the end of this interval at 00:49 UT, just when the launch site was coming into reach of the FIA Radar 2.

I feel the launch right at the end of this interval is no coincidence: they picked a moment where prior to launch they would have a substantial gap in US satellite surveillance available to complete their launch preparations. The one-hour long interval seems to have provided the North Koreans enough time to remount whatever they dismounted or camouflaged as a ruse, and launch.

(some remarks on the analysis and movie above: for a few of the satellites shown, positions are not 100% certain. For example, the Keyhole USA 186 hasn't been observed for a while because of the midwinter blackout. Satellites included in the analysis are the Japanese IGS, the US Keyholes, Lacrosses and FIA [edit: plus SPOT, Worldview and Quickbird commercial imaging satellites]).

Update 17/12 12:45 UT: 
I initially forgot to include the GeoEye Worldview and Quickbird commercial imaging satellites in the analysis. These commercial sats are frequently hired by the US government for selected imaging and used by independent analysts as well.

I have now added these satellites to the analysis, and the one-hour gap coverage between 11 Dec 23:45 and 12 Dec 00:45 UT keeps standing:

click image to enlarge

Update 17/12 16:00 UT:
Also added the French SPOT satellites to the analysis. Again, the 1-hour coverage gap between 11 Dec 23:45 and 12 dec 00:45 UT keeps standing.

Korean Spooks on my weblog?

There is a bizarre twist to this all that involves this weblog. In the late morning of December 8th, four days before the launch, an IP solving to North Korea visited this weblog. It entered through web-searches that included the keywords 'tle', 'KH-12' and 'Lacrosse 5'. A screenshot of the web statistics is below:

click image to enlarge

North Koreans with access to international websites are about as rare as, well, North Korean unicorns. Only a very select handful of North Koreans -mostly direct family members of Kim Jong Un- are allowed access to the internet.

Disclaimer: I was (and am) slightly suspicious. IP's can be spoofed, and two things caught my eye. One is the OS listed, Windows Xp. N-Korea is supposed to have its own OS, 'Red Star'. But then, maybe they only use this for their own, completely internal version of the internet. Or maybe western webstatistics providers cannot properly recognize it and list it as Xp (plus it could be a knock-off of Xp, even).

Second initially suspicious detail: the 10:05 and 10:07 visits have the word "satelliet", not "satellite" in the search string. That raised some suspicion as "satelliet" is the Dutch word for "satellite". However: that could also be a simple typo (switching the last two characters - a very common kind of typo) instead of a Dutchman typing.

Assuming that this was a real N-Korean visit, then the visit is highly interesting with reference to the apparent ruse played on US satellite surveillance of N-Korea as analysed above.

For here we apparently have a North Korean, a country where the average Kim is not allowed access to the internet, looking for orbital information on US surveillance satellites on my weblog!

This moreover was someone with at least some knowledge of satellites - again, not your average North Korean Kim, but suggestive of someone from the NK space program or intelligence program. The specific keywords 'tle' (two-line elements, i.e. a set of satellite orbital elements) and 'Lacrosse 5' (a US radar imaging satellite) and 'KH-12' (US Keyhole-12/Advanced Crystal optical imaging satellites, i.e. the satellites USA 129, USA 161, USA 186 and USA 224) bear this out.

Yet this person wasn't perhaps entirely informed. He or she searched for orbital information on those US optical and radar imaging satellites that form the backbone of US space-based surveillance, but notably missing from the search queries is the most recent addition to the US radar surveillance constellation, the two FIA Radar satellites. Also missing are Japan's IGS satellites. But, maybe, after checking for the KH-12 and Lacrosse 5 they realized they should not be on my blog for this information - they should be at Mike's website for that.

NOSS 3-1 A & C no longer a pair, and Lacrosse 3 is missing

On November 14th and 15th, Alan Figer from France first noted that one of the objects of the NOSS 3-1 pair (2001-040 A & C) was missing. Following up on his message, I could confirm this the next evening, using photography and video. Only one object instead of the usual close pair of two was visible:



Above is the video footage that was shot by me. What turns out to be the A-component can be seen crossing Lyra (bright star is Vega. The glow in the lower left corner is from a nearby lamp), but no C component is to be seen in this video segment (nor was it for one minute before and 3 minutes after this segment). Next, Derek Breit missed it as well in a window of 8 minutes centered on the A object pass, and so did Brad Young.

Over the past few days, two possible obervations have been made of the missing C-object, now well away from the A object, by Brad Young and Bill Arnold.

The break-up of the NOSS 3-1 pair probably means it had reached end of mission. It is interesting to see that some of the older NOSS pairs (and one trio) do still  maintain their pair bonding though..

Lacrosse 3 has gone missing - perhaps deorbitted

Another satellite, the 14 year old SAR satellite Lacrosse 3 (1997-064A) has gone missing in a more serious way. It has not been seen since early October. Several observers including me and Pierre Neirinck have done plane searches but so far, it hasn't been recovered. So it has either manoeuvered into a completely different orbit, or has been de-orbitted. If the latter is true, this possible de-orbit comes half a year after the de-orbit of Lacrosse 2 late March 2011. It leaves two remaining Lacrosses  in orbit (Lacrosse 4 and 5).

The Lacrosse 5 (05-016A) "disappearance trick": comparison of different occasions

Note added 13-11-2011:  visitors coming here through the link on Spaceweather.com, please read this story here first (click link) as there seem to be misunderstandings of what the video shows.


I am behind with reporting my observation activities over the last two weeks. Hereby a quick report however on one part of the observations: the Lacrosse/Onyx 5 (05-016A) SAR satellite.

Amongst the other Lacrosses (4 still in orbit, including Lacrosse 5) Lacrosse 5 is different in that it displays sudden and prominent brightness changes: from very bright (typically +1.5 or better) it goes to naked eye (near) invisibility, with a magnitude drop of at least some 3 magnitudes, in a matter of seconds. After that, it sometimes stays faint during the remainder of the pass: and sometimes it brightens up again after a while, sometimes followed by a second fading event.

This behaviour was coined the "disappearance trick" by me a few years ago. Although the earlier Lacrosses show some brightness variation as well, none shows it so clearly as Lacrosse 5, meaning something in the design of this satellite is different from its predecessors.

I have now been able to capture the satellite in the event of doing the "trick" three times: on 26 September 2009 during the BWGS meeting at Leo's place in Almere; and in the last two weeks on 24 February and 1 March 2010. The pictures and derived brightness profile of 26 September 2009 can be seen here: below are two pictures of the recent 24 February and 1 March observations.

click images to enlarge

The captured 24 February occasion was a case of Lacrosse 5 re-appearing and then disappearing again for a second time during the same pass.

I have combined the brightness profiles of all three events mentioned above into one comparison diagram. In all cases the curves are composites of 2 or 3 images taken during the pass in question (hence the non-continuous nature of the curves: the gaps are periods inbetween two pictures with no data recorded). The shown lines are 15-point averages to the pixel brightness along the trail.

click diagram to enlarge

It is clear from this comparison that the character of the brightness drop is not the same on all occasions. The 26 September 2009 event for example is more steep and sudden than the more gradual 24 February 2010 event. The 26 September 2009 event on the other hand compares relatively well to the 1 March 2010 event, the latter being perhaps slightly less steep.

Another thing notable is the suggestion of a omni-present brief shallow dip in brightness preceding the "disappearance" event by some 15 seconds (it can be seen near the 10 seconds mark in the diagram).

It is still difficult to make sense of this all. What are we seeing here? Is it a matter of strongly differing reflectance properties of the satellite body with illumination angle? Is it some brightly reflecting appendage on the satellite disappearing from view? Is it a dark appendage on the satellite starting to block view of the illuminated satellite body, or casting a shadow on it? Is it due to some moving part of the satellite, e.g. a moving dish antenna?

Phillip Masding has also probed the strange brightness behaviour of Lacrosse 5: his page with results is here and can be used as a comparison to the results I report above.

Nice pass of USA 129

The evening initially started clear. I observed the ISS, the Lacrosse 3 & 4 (97-064A & 00-047A) and the Keyhole USA 129 (96-072A).

Lacrosse 3 was very bright (+1) while descending to the west, showing multiple slow flares. USA 129 was very nice, +2.5 and grazing the tip of the Big Dipper's tail. It resulted in the nice picture below. The bright star grazed halfway by the trail is eta Uma, the tip of the Big dipper tail. Alcor and Mizar are in top. Movement is from righ to legt. The smudge at the left edge of the picture is clouds.

(click image to enlarge)

Lacrosse 5 passing alpha Persei

Earlier this week, on February the 24th, the generally very bad weather of this moment gave way to a short period of clear skies after dusk. This allowed me to obtain some positions on the bright SAR satellite Lacrosse 5 (05-016A) and it's spent rocket booster Lacrosse 5r (05-016B).

Below is an image showing Lacrosse 5 passing close to alpha Persei and the alpha Persei star association.

(click image to enlarge)

A very clear night, Lacrosses, the Breeze-M tank and the Pleiades

Yesterday evening (22 Dec) was very clear. I obtained photographs of the passes of the Lacrosse 5 rocket (05-016B), and Lacrosse 4 (00-047A)..

I photographed Lacrosse 4 with the Pleiades just before eclipse (see below). When inspecting the image for astrometric reduction, I noted a second, fainter trail on the image. Measuring it and running an ID, I found it was close to predicted positions for the Breeze-M (deb) tank, 05-019C. There was an odd 0.6 degree discrepancy though. Mike solved it by pointing out that a SDP4 solution yielded perfect residues, while the SGP4 theory SatFit uses doesn't. So, the question mark plus the "UNID" in below image can be erased.

(click image to enlarge)

Later that night, after the LEO window closed, I spent some time doing astrophotography with my camera piggyback on my Meade ETX-70. I still have to stack part of the images, but already finished stacking 102 x 10s exposures of the Pleiades with the EF 50/2.5 lens, yielding this result:

(click image to enlarge)

Short observing session

Saturday evening saw a short break in the bad weather, and some clear sky. A slight haze and near full moon made the conditions not too excellent, but I managed to catch positions on Lacrosse 5 (05-016A) and the NOSS 3-2 duo (03-054A & C).

Below is a picture of the latter crossing near Polaris.

(click image to enlarge)

Rich batch of objects

The night of 13-14 September was a very clear one. The near-full moon was low in the sky and the sky very transparent.

I hauled a rich batch of objects, including 8 positions on the KeyHole USA 129 (96-072A), the Lacrosses 4 & 5, (00-047A & 05-016A), and the NOSS duo's 3-1 and 3-2 (01-040 A & C, 03-054 A & C).

USA 129 made a magnitude 0 flare at 20:19:20 UTC. The descending part of the flare was captured on photograph.

(click images to enlarge)

Flares, strays and spy sats

The evenings of September 1st and 3rd saw a nice catch of satellites. My new camera system (Canon EOS 450D + EF 50/2.5 Macro) really is a sat magnet, which is also apparent by the number of strays captured in images with classified objects.

Objects imaged these nights include the KeyHole satellites USA 129 (96-072A) and USA 186 (05-042A), the SAR sats Lacrosse 4 & 5 (00-047A and 05-016A), and the Japanese sats IGS 1A and IGS 1B (03-009A and 03-009B).

IGS 1A is an example of a sat that would normally be beyond reach of my older camera system, but is well within reach now. The KeyHoles are captured much more easily now too.

Moreover, the quality of the positions obtained seems to be better. This is due to both the better image quality (less ambiguity in the start and end of the trails, as the images are much less noisy and the trails brighter), and to a much better, consistent timing behaviour of this camera.

Because of the more narrow field of the EF 50/2.5 Macro lens, I employ the laser (the same I use for pointing my telescope) to point the camera. Below is a photograph of what this looks like (although in reality the beam is less bright visually: this is the result of a 10 second exposure). Stars visible are from Cassiopeia and Perseus, with the double cluster visible just beneath the laser beam.

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On September 1st, I watched Lacrosse 5 (05-016A) together with my neighbour. It was nice and bright, and did it's infamous "disappearance trick" while just past the zenith. I had just been explaining this peculiar behaviour to my neighbour, so he got a nice demonstration!

Some nice flares were captured too these evenings. Below images show a mag. -8 flare of Iridium 72 on 3 Sep 20:15:29 UTC, and a brief mag 0 flare/glint by KeyHole satellite USA 129 (96-072A) at 20:33:34 UTC on the same evening. The curtain-like structure on the Iridium image is due to a moving patch of clouds.

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Several strays were captured as well, mostly spent Russian rocket boosters.

Lacrosses and a very fine USA 161 flare

Coming back from a date shortly after midnight of August 23-24, I noted it was very clear, with only occasional small cloud fields passing. This allowed me to photographically target the optical imaging Keyhole satellite USA 161 (01-044A) and the radar Lacrosses 4 & 5 (00-047A & 05-016A).

USA 161 briefly brightened in Cassiopia, featuring a very short mag. 0 flare at 23:44:09 UTC. I was so lucky to have the camera open at that time, resulting in this very fine flare picture (with below it, the brightness profile):

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IGS 1B flare, no Perseids

Yesterday was a strange evening. The day had been very clear, but with very strong wind (with gusts up to 100 km/h). In twilight, some clouds came in. It then got completely clouded, cleared again, and finally got clouded again, including a thunderstorm.

This all made me miss the Perseid meteor maximum. During the clearings however, I did manage to catch Lacrosse 2 (91-107A, in twilight), and the failed Japanese satellite IGS 1B (03-009B).

The latter was very bright (about +0.5) in the southeast and east. It then faded notably to +3, +3.5 just past east, and finally flared brightly to -1.5 in the northeast around 21:03:55 UTC.

I got three images of both satellites, totalling 11 positions (I dropped the faint trail end of the third IGS 1B image). The three IGS 1B images showed a second, very faint trail as well, which turned out to be the classified research MSX satellite (96-024A).

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USA 129, and an unknown object

Friday evening was clear, albeit with occasional wisps of cirrus traversing the sky. Back home from my new job in which I started last week, I could do some observing again.

First I tried to observe two predicted zenith passes of USA 193 debris, but didn't spot anything.

Next target was Lacrosse 3 (97-064A). I selected a star field close to beta Umi near RA 15:00, dec +76 45', through which Lacrosse 3 would pass at 19:46:30 UTC (March 7).

Just before the expected appearance of Lacrosse 3 in the FOV, suddenly a very fast object of about mag. +7.5 crossed through the lower part of the (4 degree) FOV. It moved west-east and roughly parallel to the predicted Lacrosse track. It was very fast, maybe even moving as fast as 1.5 degree/second. It caught me completely by surprise, so it took me some time to realize what happened and try to fix an approxiate time. With a plus-minus of say 20 seconds in time, the resulting position (in IOD format) is about:

99999 08 999A 4353 G 20080307194600000 17 75 1511063+756260 36 S

Given the fast speed and general direction of movement, my thought was immediately that this could be a piece of USA 193 debris. It doesn't match any of the published catalogued debris pieces though. And according to Ted, it would be somewhat too far from the expected plane of these fragments. So the object remains unidentified.

Some 30 seconds later Lacrosse 3 sailed into the FOV.

Other objects tracked that evening were all of the NOSS 3-4 objects (07-027A, B and C) including the Centaur rocket, the NOSS 2-3 objects (96-029C, D and E). I also observed two of the KeyHole photo-reconnaissance satellites: USA 129 (96-072A) which initially was bright, and USA 186 (05-042A). They were all early, especially USA 129.

I catched the latter on photograph too, while it crossed close to Castor and Pollux in Gemini, being about mag. +0.5:

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All in all, 16 positions were logged on 10 objects this evening, two of which were camera positions, the rest was visual. The visual position obtained for USA 129 and the two camera positions agree well.

Flaring KeyHole USA 129, and two productive evenings

The last two evenings saw a very clear sky again. Tuesday evening was cold and windy, yesterday evening a bit more comfortable. I obtained a rich batch of positions using both the telescope and the camera: 20 positions on 9 objects on the 26th, and 18 positions on 7 objects yesterday evening. These objects include KeyHoles USA 186 and USA 129, Lacrosse 4, the Lacrosse 5 rk, and various NOSS components.

Yesterday evening at about 20:38 UTC the KeyHole USA 129 (96-072A) flared while crossing Perseus. I was observing it through the telescope at that time and noted it was bright and then faded. I cannot give an exact peak time and magnitude however, as I was concentrating on obtaining positions. I had the camera open at that time, and it catched the onset of the flare very nicely:

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Here is the brightness profile:

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I also captured Lacrosse 4 (00-047A) on photograph, and observed it visually. It was on time, but definitely somewhat off-track.

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I tried in vain to spot the USA 193 debris pieces D and K last evening.

Finally, another picture of the KeyHole USA 129 (this time steady in brightness) shot on the evening of the 26th:

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Lacrosse 2 manoeuvre, and bad luck with a stopwatch

Yesterday was a very clear day, so in twilight I set up the ETX-70 to gather positional data on Lacrosse 2 (91-017A), the NOSS 3-3 (05-004 A & C) duo and the NOSS 3-4 (07-024A & C) duo.

I had adapted the home-made piggyback camera adapter slightly, so it can also funtion as a rest for my 5 mw green laserpointer. The drawback of the ETX-70 is that it doesn't come with a finderscope, so I use the laser to point the telescope. A 5 mw green laser gives a tens of meters long visible beam at night pointing to where you point the scope if you shine it parallel to the scope tube. Simple, and works like a charm.

Unfortunately, after succesfully observing passes of NOSS 3-3 A & C and Lacrosse 2 I must have hit a wrong button on the stopwatch by mistake. When I had pointed the telescope to the point near where NOSS 3-4 A & C should pass and took up the stopwatch, I discovered to my horror that it was no longer running and had no lap times in it's memory! I lost all gathered points so far.

Next, in the confusion of having to start up the stopwatch anew just before the NOSS 3-4 duo pass, I lost that pass.

Now, I can't quite stand such things happening, it makes me very irritated for a while. Luckily my neighbours have double-pane glass, so probably they did not hear my swearing...

What saved the night was that before turning to the telescope, I had triggered the Ixus camera in addition during the Lacrosse 2 (91-017A) pass. The trail showed up faint but well enough defined to measure against the late twilight sky, which meant I had an image providing two positions.

After data reduction, it turned out that the satellite was 17.3 seconds early relative to Mike's 07357.17849791 TLE. On the 6th of January, the difference to this TLE was 1 second. So I reckoned 91-017A must have made a manoeuvre recently. Which, it turns out, it indeed did, a small manoeuvre changing the mean-motion slightly on or near the 6th. What I had missed was that Mike had just issued and update of the 91-017A orbit incorporating the manoeuvre yesterday morning.
That 91-017A still does manoeuvre, points out it is still alive and probably still being used for reconnaisance almost 17 years after it was launched.

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Lacrosse 2 (91-017A) crossing through Cygnus 17.3 seconds early

I set my alarm-clock to see if it would still be clear in the morning (allowing me in that event to catch amongst others Progress M-61). But alas, it had become overcast.

NOSS-es, Lacrosses and ISS

Yesterday evening the 9th it was clear in twilight, but clouds came in a while later. Nevetheless there was time enough to get out the ETX-70 again and bag the NOSS 3-4 duo (07-027A and 07-027C), the NOSS 3-3 duo (05-004A and 05-004C) and Lacrosse 3 (97-064A). In total, 7 points were obtained. In the morning of the 10th, I observed the International Space Station just before clouds again interfered.

About 3 minutes before the NOSS 3-4 duo pass, another faint sat crossed the telescope field in a similar trajectory. I was just making a last check of the star field in view against a plotted map to ensure I had the correct location in view, so hadn't the stopwatch in my hands. At first I was a bit worried it was one of the 07-027 objects but very early, so I was relieved when 3 minutes later the real 07-027A sailed into the FOV.

Later that night it cleared again. Below is the image of the ISS I shot a few hours later, during the morning hours. It can be seen passing from Corona borealis into Hercules. It was bright, around mag. -4. My main intended target for that early morning was Progress M-61, but clouds (already visible in the ISS image) intervened.

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USA 193, first ETX observations of NOSS 3-4, and comet 17P/Holmes

Last two nights (the evenings of 2008 Jan 5 and 6) were the first nights I tried to do visual position determinations on fainter satellites. Targets were the NOSS 3-4 A & C pair (07-027A & 07-027C).

The Meade ETX-70 (see picture below), a small and compact 7 cm/f 350 mm (F5) rich-field refractor, turns out to be a very nice instrument for satellite observing. It was cool to see 07-027A sail majestically in and out of the FOV, half a minute later followed by 07-027C. At 14x magnification with the 25 mm eyepiece, the FOV is over 3 degrees with (from the light-polluted mid-town location Cospar 4353 in Leiden center) a limiting magnitude at mag. +9.5.

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The Meade ETX-70. Attached is a home-made piggyback mount for my camera

I had some problems operating my (new too) stopwatch though. During the Jan 5 attempt, I pushed a wrong button when I wanted to read out the memory, resulting in the loss of all 4 points. During the Jan 6 attempt, I did the same with 2 points on 07-027A after I had succesfully retrieved 2 points on 07-027C (plus another point on the same object taken during an earlier pass). Evidently, I still need some practise. Logging with the stopwatch, estimating the fraction between two stars crossed, and operating Ted's Obsreduce software all went surprisingly well though.

On Jan 5th in deep twilight I observed USA 193 (06-057A) zipping by. I got two camera points on it but apparently the times are off. This failed (?) reco sat keeps being a fine object to view as it is bright and very fast. If it's orbit continues to decay as it does now, the object will end its life around the first week of April.

On Jan 6th I observed, apart from the NOSS 3-4 pair, also Lacrosse 2 & 3.

The evening of January 6th was very clear, and I used the ETX-70 to function as guiding mount for the Canon Ixus camera. Target: comet 17P/Holmes.

The comet has grown very large (about 1.12 degree currently) and vey diffuse. Below is a photograph showing the comet which is a stack of 39 images of 15 second exposure each. The open cluster in top of the image is M34, the bright star below the comet is Algol. Because the ETX-70 is on an alt-azimuth mount and the comet was near the zenith, where the effect is largest, some field rotation is visible in the stars near the image edges.

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IGS-es, USA 193, and other stuff during beautiful clear nights

SatTrackCam Leiden just experienced a few beautifully clear, dark & transparent nights. The result is a fine batch of positions on several objects, including Keyholes (USA 161), Lacrosses (3, 4 & 5), USA 193 and the old & new Japanese IGS-es. The latter include my first positions on IGS 4A/R2 (07-005A).

The first capture of the latter object was when I was waiting for its rocket launcher (IGS 4r/R2r, 07-005C) on the night of May 17-18. Suddenly a bright (+2) object appeared 2 minutes before 07-005C should, following a similar trajectory. I made a photograph and then found out it was the A component.

Due to a goof from my side I initially thought it was the optical satellite (due to it having the "A" designation, analogue to IGS 1A, 03-009A) and hence was surprised to find it was so bright. Only later I realized it is the (intrinsically brighter) radar sat.

Keyhole USA 161 (01-044A) was observed flaring on the 18th at 00:12:50 UTC (-1.5, slow) and 00:14:13 UTC (-1, short).

USA 193 (06-057A) was bright.

Lacrosse 5 (05-016A) was elusive. On the 18th, it initially was +2 low in the sky but then quickly faded beyond vision for much of the pass.

Below are trail images of the "new" IGS 4A/R2, it's rocket 4R/R2r cruising through Lyra, Lacrosse 3 cruising amongst the Coma cluster stars, and an Iridium flare in twilight.

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Flares of Iridium 14, ISS (!), USA 186 and Lacrosse 4

This evening (the 16th) and the evening of the 14th I observed two nice flares of the same Iridium satellite, Iridium 14 (99-032A). On the 14th it flared to mag. -5, and this evening to -6 (top foto), in twilight. Less than a minute earlier Iridium 70 flared at virtually the same position, but less brightly.

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The International Space Station (ISS) made a number of fine bright passes as well the past days. below are two images of April 14 and 15, including a fine mag. -3.5 twilight pass (top image).

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My new neighbours were on the courtyard enjoying the mid-summer like temperatures (+28 C daytime this weekend, very unusual for mid-April) when I was targetting the twilight pass on the 15th. Seeing me put up my tripod, they asked me what I was doing. I explained, and then pointed out the rising ISS to them. At first they didn't believe me, thinking it was an aircraft, but then they realized I had predicted it to appear, so I probably was right. Still, I could see a look in their face that probably meant something like: "A nutter, but not a dangerous one...".

ISS did something unusual during the 2nd evening pass on the 15th. It was low in the west crossing into Gemini at mag. -2 or so, when suddenly (as if a switch was turned) it flared up by at least 1.5 to 2 extra magnitudes, for maybe a second or 2-3, and then back to its previous brightness again. Very conspicuous. I also had the impression of an orange colour but that could be due to the low elevation. Never seen this before with ISS. Time was approximately 21:07:15 UTC (Apr 15).

Lacrosse 4 (00-047A) flared as well that evening, briefly to mag. +0.5. This was either at 23:09:53 or 23:10:03 UTC (there is some confuson with me about the correct time).

05-042A (USA 186) shortly flared to mag. 0 at 19:45:58 UTC on Apr 15. I catched this flare on photograph but it is so short it is almost stellar. I saw it flare again on the 16th at 20:08:27, to mag. -1 and again very short (maybe a second duration).

Strangely enough I again failed to spot IGS 1B (03-009B), the Japanese radar satellite that recently had a power failure, on the 15th. This although this was a zenith pass, with the sat emerging out of eclipse in the zenith. But I could see no trace of it visually and on the photographs. This while previously this satellite would easily be visible, attaining magnitude +1.5 to +2 during high passes.

Especially the 15th resulted in a nice batch of positions on various objects.