Wired.com has published a short photographic item about secret spacecraft today.
Two of the images in it were shot by me: a photograph of Lacrosse 3 and one of Mentor 4.
Friday, 15 July 2011
Tuesday, 12 July 2011
Prowler
Among the family of classified satellites, three stand out as more mystifying than the rest: Misty 1 & 2, PAN, and Prowler.
The latter has long existed in the realm of rumours only. It was launched by Space Shuttle Atlantis on mission STS-38, which was a classified DoD mission launched on 15 November 1990. Officialy only one satellite, USA 67, was launched from the Atlantis payload bay. This is believed to be a geostationary SDS communications satellite, SDS 2-2.
USSTRATCOM released catalogue numbers (but no public orbit) for three objects connected to this launch: the SDS satellite USA 67 itself (90-097B, 20963) plus two rocket bodies (90-097 C & D, 20964 and 20965).
The latter was puzzling, as it is one too many (see the discussion by Ted Molcan here), This was the start of the idea that a second, unacknowledged object was launched by STS-38 as well.
In 2004 an NBC journalist referred to such a secret payload by the name of Prowler, in a news-item discussing a Senate debate about a classified spy satellite program drawing criticism for massive cost overruns. The same journalist, citing anonymous sources, did so again in 2007.
According to these stories, Prowler was an experimental satellite used for close inspection of other (non-US) satellites in geostationary orbit (see discussion here), reportedly coming to within decimeters of some satellites. There are suggestions that it was a test of technology which, in wartime, could be used to sabotage enemies' space assets. It was also said to employ stealth technologies to evade easy detection.
Meanwhile, US amateur observers Ed Cannon and Mike McCants had discovered an unidentified near-geostationary object in July 1998. As time progressed and more and more ISON and amateur-discovered objects could be identified with specific launches, this one was one of few left unidentified. This in turn led to suggestions that the object in question was the rumoured unacknowledged STS-38 launch, Prowler. It was likely discovered only after its active lifetime ended, and it was put in a disposal orbit (see below).
Since then, a long term analysis by Ted Molczan has strengthened this identification. The object has al the right characteristics in terms of brightness behaviour and orbital behaviour. It currently is in an unusual librating disposal orbit that seems devised to keep it out of reach of Soviet tracking facilities (see discussion in depth by Ted here). In a second analysis, Ted showed that STS-38 indeed had the opportunity to launch this object and some tell-tale clues to that are present in the manoeuvering history of STS-38 Atlantis. The whole history of the object, from launch onwards but also including the final disposal orbit when the stealth character of the object was lost, was designed with low detectability by Soviet tracking facilities in mind (see Ted's discussion here).
The object now resides in a currently 13-degrees inclined orbit librating between 73 W and 136 W, putting it over the eastern Pacific, with visibility from the western United States. Over the past two weeks , I imaged it a number of times, using the 0.61-meter "remote" telescope of Sierra Stars observatory in California. Below is one of the better images, shot on the morning of July 6th:
The latter has long existed in the realm of rumours only. It was launched by Space Shuttle Atlantis on mission STS-38, which was a classified DoD mission launched on 15 November 1990. Officialy only one satellite, USA 67, was launched from the Atlantis payload bay. This is believed to be a geostationary SDS communications satellite, SDS 2-2.
STS-38 mission patch
USSTRATCOM released catalogue numbers (but no public orbit) for three objects connected to this launch: the SDS satellite USA 67 itself (90-097B, 20963) plus two rocket bodies (90-097 C & D, 20964 and 20965).
The latter was puzzling, as it is one too many (see the discussion by Ted Molcan here), This was the start of the idea that a second, unacknowledged object was launched by STS-38 as well.
In 2004 an NBC journalist referred to such a secret payload by the name of Prowler, in a news-item discussing a Senate debate about a classified spy satellite program drawing criticism for massive cost overruns. The same journalist, citing anonymous sources, did so again in 2007.
According to these stories, Prowler was an experimental satellite used for close inspection of other (non-US) satellites in geostationary orbit (see discussion here), reportedly coming to within decimeters of some satellites. There are suggestions that it was a test of technology which, in wartime, could be used to sabotage enemies' space assets. It was also said to employ stealth technologies to evade easy detection.
Meanwhile, US amateur observers Ed Cannon and Mike McCants had discovered an unidentified near-geostationary object in July 1998. As time progressed and more and more ISON and amateur-discovered objects could be identified with specific launches, this one was one of few left unidentified. This in turn led to suggestions that the object in question was the rumoured unacknowledged STS-38 launch, Prowler. It was likely discovered only after its active lifetime ended, and it was put in a disposal orbit (see below).
Since then, a long term analysis by Ted Molczan has strengthened this identification. The object has al the right characteristics in terms of brightness behaviour and orbital behaviour. It currently is in an unusual librating disposal orbit that seems devised to keep it out of reach of Soviet tracking facilities (see discussion in depth by Ted here). In a second analysis, Ted showed that STS-38 indeed had the opportunity to launch this object and some tell-tale clues to that are present in the manoeuvering history of STS-38 Atlantis. The whole history of the object, from launch onwards but also including the final disposal orbit when the stealth character of the object was lost, was designed with low detectability by Soviet tracking facilities in mind (see Ted's discussion here).
The object now resides in a currently 13-degrees inclined orbit librating between 73 W and 136 W, putting it over the eastern Pacific, with visibility from the western United States. Over the past two weeks , I imaged it a number of times, using the 0.61-meter "remote" telescope of Sierra Stars observatory in California. Below is one of the better images, shot on the morning of July 6th:
click image to enlarge
Wednesday, 6 July 2011
An update on IGS-1B
Along the line of expectations, our tracking data show that the Japanese spy satellite IGS 1B (2003-009B) which malfunctioned in March 2007, keeps coming down (see earlier coverage here and here).
Early July 2011, the perigee had come down to 450 km and the Mean Motion (the number of orbital revolutions per day) is steadfastily increasing as the orbit becames more narrow:
The predicted decay date keeps shifting back and forth, being highly dependant on solar activity. Solar activity has been back to modest the past two months. As a result, the decay date forecast has shifted further away in time.
If solar activity does not increase, forecasted decay will be in late 2013 (SatEvo with current solar flux F10.7 cm = 85, elset 11184.15154535). If it does increase - which is likely, as we are on the approach to a solar maximum - it will be earlier, possibly as early as mid-2012.
Meanwhile, it is interesting to see how the still active sister-ship IGS 1A (2003-009A), launched in the same 2003 launch, is faring. Above diagram shows the evolution of the orbital inclination. IGS 1B's orbital inclination is clearly drifting, consistent with loss of control. IGS 1A's orbital inclination initially was allowed to co-drift with IGS 1B, but then altered in a manoeuvre mid-2008 that brought the inclination up again, to match the other IGS-es in the constellation. As of 2010, it is kept more or less steady, librating around a value of 97.39 degrees, the sun-synchronous value for a 487 x 498 km orbit.
Early July 2011, the perigee had come down to 450 km and the Mean Motion (the number of orbital revolutions per day) is steadfastily increasing as the orbit becames more narrow:
The predicted decay date keeps shifting back and forth, being highly dependant on solar activity. Solar activity has been back to modest the past two months. As a result, the decay date forecast has shifted further away in time.
If solar activity does not increase, forecasted decay will be in late 2013 (SatEvo with current solar flux F10.7 cm = 85, elset 11184.15154535). If it does increase - which is likely, as we are on the approach to a solar maximum - it will be earlier, possibly as early as mid-2012.
Meanwhile, it is interesting to see how the still active sister-ship IGS 1A (2003-009A), launched in the same 2003 launch, is faring. Above diagram shows the evolution of the orbital inclination. IGS 1B's orbital inclination is clearly drifting, consistent with loss of control. IGS 1A's orbital inclination initially was allowed to co-drift with IGS 1B, but then altered in a manoeuvre mid-2008 that brought the inclination up again, to match the other IGS-es in the constellation. As of 2010, it is kept more or less steady, librating around a value of 97.39 degrees, the sun-synchronous value for a 487 x 498 km orbit.
PAN, and the NOSS 3-5 duo
Monday evening was a nice clear evening with a very transparent sky.
I observed the NOSS 3-5 duo (11-014 A & B), which was captured in a very fine image with a stray nearby, the rocket from the Kosmos 1697 launch (85-097B). De double parallel trail above is the NOSS duo, the single trail under an angle is the Russian rocket (bright star near trails is Deneb):
I also took opportunity of the transparent sky to target some geostationary objects low in the southeast. Targets were PAN (09-047A) and Mentor 4 (09-001A):
I observed the NOSS 3-5 duo (11-014 A & B), which was captured in a very fine image with a stray nearby, the rocket from the Kosmos 1697 launch (85-097B). De double parallel trail above is the NOSS duo, the single trail under an angle is the Russian rocket (bright star near trails is Deneb):
click image to enlarge
I also took opportunity of the transparent sky to target some geostationary objects low in the southeast. Targets were PAN (09-047A) and Mentor 4 (09-001A):
click image to enlarge
Monday, 4 July 2011
Imaging geostationary satellites using a remote telescope [UPDATED]
I have been using the "remote" telescopes of Sierra Stars observatory in California and Winer Observatory in Nevada for some time now to image asteroids (recently, earthgrazing NEA 2011 MD).
The past two days I have used the Sierra Stars Obs. 0.61-meter Cassegrain telescope to make some "remote" images of classified geostationary satellites that are not visible from the Netherlands, but visible from the western United States. It concerned the recently launched SBIRS-GEO1 satellite (11-019A) and the mysterious object (90-097E) that is most likely Prowler, launched in 1990 on STS-38.
Below are the images: as this is a guided telescope, the satellites have created trails on the images. Top image: Prowler. Bottom image: SBIRS-GEO1, plus an unidentified object (UPDATE: the latter object might be the SBIRS-GEO r/b).
The past two days I have used the Sierra Stars Obs. 0.61-meter Cassegrain telescope to make some "remote" images of classified geostationary satellites that are not visible from the Netherlands, but visible from the western United States. It concerned the recently launched SBIRS-GEO1 satellite (11-019A) and the mysterious object (90-097E) that is most likely Prowler, launched in 1990 on STS-38.
Below are the images: as this is a guided telescope, the satellites have created trails on the images. Top image: Prowler. Bottom image: SBIRS-GEO1, plus an unidentified object (UPDATE: the latter object might be the SBIRS-GEO r/b).
click images to enlarge
Tuesday, 28 June 2011
OT: more imagery of the earthgrazing asteroid 2011 MD
Like yesterday, I used the 0.61-meter F/10 Cassegrain of Sierra Stars Observatory (G68) in California again to image the earthgrazing asteroid 2011 MD, this time a few hours after closest approach.
Below animated GIF was made from three 30 second exposures, spaced 30 seconds, starting at 09:35:01 UTC (28 June).
Below animated GIF was made from three 30 second exposures, spaced 30 seconds, starting at 09:35:01 UTC (28 June).
Monday, 27 June 2011
OT: Close Encounters of a Rocky Kind (2011 MD)
Today, a small asteroid, 2011 MD, made a very close pass by the earth, coming to within a distance of 12,400 km at about 13:30 UTC (June 27). That is well within the distance of geostationary satellites, and even within the distance of GPS satellites in MEO!
This morning, some 5 hours before closest approach, I used the 0.61-meter F/10 Cassegrain of Sierra Stars Observatory (G68) in California, to capture this PHA earthgrazer.
This image is a 30 second CCD exposure taken between 08:32:00 and 08:32:30 UTC (June 27, 2011). In these 30 seconds, the fast moving object left a notable bright trail on the image. Star field is in Serpens, image center approximately RA 15h35m57s, dec. +19.441 degrees.
UPDATE: more of my 2011 MD imagery shot on the 28th here.
This morning, some 5 hours before closest approach, I used the 0.61-meter F/10 Cassegrain of Sierra Stars Observatory (G68) in California, to capture this PHA earthgrazer.
click image to enlarge
This image is a 30 second CCD exposure taken between 08:32:00 and 08:32:30 UTC (June 27, 2011). In these 30 seconds, the fast moving object left a notable bright trail on the image. Star field is in Serpens, image center approximately RA 15h35m57s, dec. +19.441 degrees.
UPDATE: more of my 2011 MD imagery shot on the 28th here.
Monday, 6 June 2011
NanoSail-D: a brief note on how I construct these brightness curves
Some people have asked me how I get the brightness curves from my images. So here is a brief explanation.
On each image, the satellite has made a trail. Start and end times of the exposure are well known, and the start and end of the trail corresponds to these times.
Next it is as simple as using software (e.g. MaximDL, or IRIS) that can read pixel values along a line: let the software read a line that corresponds to the satellite trail on the image! With MaximDL or IRIS, this is as simple as drawing a line over the screen with your mouse, exactly over the satellite trail. The software then reads the pixel values along this line. The resulting data can be exported as a data table.
These data are then read into a spreadsheet I created, that for each data point interpolates the corresponding time (remember that the time of the first and last datapoint in the dataset is known: start and end of the exposure).
Now, this assumes the movement of the satellite on the image is linear. Strictly speaking, the apparent speed of the satellite is not linear. However, with short exposures (10s) that will not be a really big source of error.
On each image, the satellite has made a trail. Start and end times of the exposure are well known, and the start and end of the trail corresponds to these times.
Next it is as simple as using software (e.g. MaximDL, or IRIS) that can read pixel values along a line: let the software read a line that corresponds to the satellite trail on the image! With MaximDL or IRIS, this is as simple as drawing a line over the screen with your mouse, exactly over the satellite trail. The software then reads the pixel values along this line. The resulting data can be exported as a data table.
These data are then read into a spreadsheet I created, that for each data point interpolates the corresponding time (remember that the time of the first and last datapoint in the dataset is known: start and end of the exposure).
Now, this assumes the movement of the satellite on the image is linear. Strictly speaking, the apparent speed of the satellite is not linear. However, with short exposures (10s) that will not be a really big source of error.
Sunday, 5 June 2011
NanoSail-D: evolution of the flash pattern during a pass
Yesterday evening at 23:00 CEST I observed a twilight pass of the experimental NASA solar sail NanoSail-D again (see earlier and later observations here).
This pass allowed me to capture a series of brightness curves, which document the evolution of the flash pattern during a single pass, as the looking angle is changing (looking "edge on" aroudn culmination, and then more and more "on the tail"as it is descending) . The change in flash pattern is profound: this is clearly a very complex matter where the flash pattern highly depends on the relative position of the object to the observer.
It starts (image and diagram 1) with a lot of irregular flashes, spaced 0.3 - 0.9s apart (average 0.49s but with large standard deviation).
Next (image and diagram 2), a nice semi-regular sinusoid pattern develops, flashes spaced 1.24 - 1.45 s (average 1.33s)
Then (image and diagrams 3 and 4), the period increases, the pattern transforming to a slower sinusoid with peaks first 5.61s apart, then somewhat decreasing again to 4.11s apart (edit: or maybe not: the firts "peak"might be a sub-peak. The valleys seem at similar distance to the previous diagram). Superimposed on this, a shorter cycle of minor subvariation can be suspected, with various periods.
This slower variation in the last two diagrams is why Bram, me and some other observers got the impression, on this and some past passes, of the period almost "disappearing" when NanoSail-D was descending on altitudes of ~35 degrees.
Two of the trail images in a bit more detail: note the difference in flash pattern:
This pass allowed me to capture a series of brightness curves, which document the evolution of the flash pattern during a single pass, as the looking angle is changing (looking "edge on" aroudn culmination, and then more and more "on the tail"as it is descending) . The change in flash pattern is profound: this is clearly a very complex matter where the flash pattern highly depends on the relative position of the object to the observer.
click images to enlarge
It starts (image and diagram 1) with a lot of irregular flashes, spaced 0.3 - 0.9s apart (average 0.49s but with large standard deviation).
Next (image and diagram 2), a nice semi-regular sinusoid pattern develops, flashes spaced 1.24 - 1.45 s (average 1.33s)
Then (image and diagrams 3 and 4), the period increases, the pattern transforming to a slower sinusoid with peaks first 5.61s apart, then somewhat decreasing again to 4.11s apart (edit: or maybe not: the firts "peak"might be a sub-peak. The valleys seem at similar distance to the previous diagram). Superimposed on this, a shorter cycle of minor subvariation can be suspected, with various periods.
This slower variation in the last two diagrams is why Bram, me and some other observers got the impression, on this and some past passes, of the period almost "disappearing" when NanoSail-D was descending on altitudes of ~35 degrees.
Two of the trail images in a bit more detail: note the difference in flash pattern:
click images to enlarge
Saturday, 4 June 2011
NanoSail-D Galore
Yesterday evening, I observed a twilight pass (sun at -7 degrees altitude and a still bright blue sky) of NanoSail-D, the NASA experimental solar sail (see earlier posts here). It passed at 44 degrees in the east, and after culmination became very bright again, flashing to mag. 0.
Because of the bright twilight sky I had to tone down the ISO to 400 and diaphragm to F4.0. The images show the flashing behaviour very neatly, and I obtained two spectacular sinusoid brigthness curves (the second one is from the image shown):
The flash period is definitely slightly variable, varying between 1.2 and 1.5 seconds with an average of 1.35 +/- 0.12 seconds.
With the current orbit, decay is projected for mid-August.
note added: click the 'Nanosail-D' label below to see later posts on NanoSail.
Because of the bright twilight sky I had to tone down the ISO to 400 and diaphragm to F4.0. The images show the flashing behaviour very neatly, and I obtained two spectacular sinusoid brigthness curves (the second one is from the image shown):
click images to enlarge
The flash period is definitely slightly variable, varying between 1.2 and 1.5 seconds with an average of 1.35 +/- 0.12 seconds.
With the current orbit, decay is projected for mid-August.
note added: click the 'Nanosail-D' label below to see later posts on NanoSail.
Friday, 3 June 2011
Yet more bright NanoSail-D, and an unidentified object from the same launch
Yesterday evening (Wednesday evening) was very clear and saw another fine pass of NanoSail-D (10-062L), the experiental NASA solar sail. As on previous occasions, it became very bright after culmination, while descending to the southern horizon: reaching an easy naked eye magnitude of +0.5. It is still flashing, but trail saturation on the images meant I could not get a reliable brightness variation curve this time. Below are two images: one that shows it just north of the Coma Berenices star cluster, the other shows it passing south of Bootes into Virgo somewhat later (bright star in the top is Arcturus):
Tonight (Tuesday evening) I had another pass, a low west pass at 35 degrees altitude this time. And....it was invisible, to the naked eye at least.
On April 27th, Russell Eberst observed an unidentified object that moves in the same orbital plane as NanoSail-D and appears to be "something" from the same launch (see also here). It was subsequently observed by a number of other observers (and perhaps earlier, on March 3, by Greg Roberts), and yesterday I photographed it:
Another object observed this evening was Lacrosse 5 (05-016A).
click images to enlarge
Tonight (Tuesday evening) I had another pass, a low west pass at 35 degrees altitude this time. And....it was invisible, to the naked eye at least.
On April 27th, Russell Eberst observed an unidentified object that moves in the same orbital plane as NanoSail-D and appears to be "something" from the same launch (see also here). It was subsequently observed by a number of other observers (and perhaps earlier, on March 3, by Greg Roberts), and yesterday I photographed it:
click image to enlarge
Another object observed this evening was Lacrosse 5 (05-016A).
Wednesday, 1 June 2011
More flashing NanoSail-D, and flaring KH-12 USA 224
A week after my May 24 observations, I observed NanoSail-D (2010-062L) again, the experimental NASA solar sail.
As a week ago, it became very bright after culmination, while descending in the south, and was rapidly flashing again. It was easily seen by the naked eye, reaching mag. +1 or possibly +0.5.
In fact it is so bright, that the pixel brightness of the trail reached saturation on two of the three images. The first image (below) did yield brightness information: the resulting curve is shown beneath it. The flash period is irregular, but periods of 0.5s and 1.0s pop up frequently in the diagram (for actual determined flash times, see here. Astrometry on the satellite itself can be found here).
As can be seen on the images, the satellite was in a race with an untimely field of clouds (the orangish streaks in the images), staying just ahead of it. Visually, the brightness fluctuation was much more apparent than it is on these images (due to the saturation of the latter): it was very clearly flashing.
Nanosail-D was not the only object flashing. USA 224 (11-002A), the new KH-12 Keyhole launched on January 20 this year, flared too, while passing through the zenith, with flares at 23:48:27.3 and 23:48:31.8 UTC (May 31). The "saddle" and elevated brightness between the two flares is interesting (the trail is notably fainter before the first flash, and subsequent images show it is fainter again after the second flash):
This was the second time I imaged USA 224 (The first time was May 24). In addition to USA 224 and NanoSail, I also imaged another KH-12 Keyhole, USA 161 (01-044A), and a Lacrosse SAR, Lacrosse 3 (97-064A).
NanoSail-D (image: NASA/MSFC)
As a week ago, it became very bright after culmination, while descending in the south, and was rapidly flashing again. It was easily seen by the naked eye, reaching mag. +1 or possibly +0.5.
In fact it is so bright, that the pixel brightness of the trail reached saturation on two of the three images. The first image (below) did yield brightness information: the resulting curve is shown beneath it. The flash period is irregular, but periods of 0.5s and 1.0s pop up frequently in the diagram (for actual determined flash times, see here. Astrometry on the satellite itself can be found here).
click images to enlarge
As can be seen on the images, the satellite was in a race with an untimely field of clouds (the orangish streaks in the images), staying just ahead of it. Visually, the brightness fluctuation was much more apparent than it is on these images (due to the saturation of the latter): it was very clearly flashing.
Nanosail-D was not the only object flashing. USA 224 (11-002A), the new KH-12 Keyhole launched on January 20 this year, flared too, while passing through the zenith, with flares at 23:48:27.3 and 23:48:31.8 UTC (May 31). The "saddle" and elevated brightness between the two flares is interesting (the trail is notably fainter before the first flash, and subsequent images show it is fainter again after the second flash):
click images to enlarge
This was the second time I imaged USA 224 (The first time was May 24). In addition to USA 224 and NanoSail, I also imaged another KH-12 Keyhole, USA 161 (01-044A), and a Lacrosse SAR, Lacrosse 3 (97-064A).
Wednesday, 25 May 2011
Nanosail-D: a spectacular show of bright flashes!
Last night I finally was able to capture Nanosail-D (10-062L), the NASA experimental solar sail. It put on a spectacular show, flashing rapidly, becoming an easy naked-eye object after culmination when it reached magnitude +1.
As it gradually brightened from invisibility to naked-eye brightness while passing at 61 degrees altitude due east, it initially flared rapidly, in an irregular pattern, at a rate of 1 to 3 flashes per second. below is the first image, and two other where the trail runs out of the image frame (in haste, I aimed badly when repositioning the camera):
When it descended towards the South-Southeast, it became brighter, reaching mag. +1. The flashing pattern became somewhat more regular and slowed down to about one flash per 1.6 seconds. On the image, the trail is quite saturated and hence the brightness variability on the image below is less apparent than it was visually. Visually, the objet was clearly "winking", very cool to see:
As it gradually brightened from invisibility to naked-eye brightness while passing at 61 degrees altitude due east, it initially flared rapidly, in an irregular pattern, at a rate of 1 to 3 flashes per second. below is the first image, and two other where the trail runs out of the image frame (in haste, I aimed badly when repositioning the camera):
click images to enlarge
When it descended towards the South-Southeast, it became brighter, reaching mag. +1. The flashing pattern became somewhat more regular and slowed down to about one flash per 1.6 seconds. On the image, the trail is quite saturated and hence the brightness variability on the image below is less apparent than it was visually. Visually, the objet was clearly "winking", very cool to see:
click images to enlarge
Thursday, 12 May 2011
PAN at its new slot at 45.0 E
Below is an image I shot in the evening of May 9, under not too good conditions (moonlight, and some twilight left).
It shows PAN (09-047A) in its new position at 45.0 E, following the relocation from 49.0 E early May.
Image was shot using the Carl Zeiss Jena Sonnar MC 2.8/180 mm.
It shows PAN (09-047A) in its new position at 45.0 E, following the relocation from 49.0 E early May.
Image was shot using the Carl Zeiss Jena Sonnar MC 2.8/180 mm.
click image to enlarge
Tuesday, 10 May 2011
ISS over the Sun
Late this afternoon (10 May 2011), at 17:29:25 CEST (15:29:25 UTC), the International Space Station (ISS) passed in front of the Sun disc again as seen from the SatTrackCam station, silhoueting the Space Station on the solar disc.
Like on March 24th, I used my small ETX-70 telescope equiped with a Solar Screen Filter, to photograph the event. This time I used prime focus plus a Kenko 2x converter, instead of eyepiece-projection, effectively yielding a f=700mm F/10 system.
Four images out of the series show the ISS silhouted againts the sun, along with several sunspots. Below is a composite image of the four images (showing the ISS four times), plus a detail. The ISS solar arrays are well visible.
Like on March 24th, I used my small ETX-70 telescope equiped with a Solar Screen Filter, to photograph the event. This time I used prime focus plus a Kenko 2x converter, instead of eyepiece-projection, effectively yielding a f=700mm F/10 system.
Four images out of the series show the ISS silhouted againts the sun, along with several sunspots. Below is a composite image of the four images (showing the ISS four times), plus a detail. The ISS solar arrays are well visible.
click images to enlarge
Monday, 9 May 2011
UNID-I 3 May 2011 = PAN [UPDATED]
On May 3rd, I found two unidentified geostationary objects close to Galaxy 27 and Intelsat 12 (see report and pictures here).
One, UNID-I, was stable in brightness. The other, UNID-II, was flashing. I imaged UNID-I the next night (May 4th) as well, showing it drifting westwards. I might have imaged UNID-II again too, though misidentifying it at that time as Intelsat 12 (except for the occasionally very bright UNID-II, the objects were, due to worse observing conditions, at the edge of detectability).
At that time (see the link above) there already was some suspicion that UNID-I could be the enigmatic classified geostationary satellite PAN (09-047A), caught in the act of yet another relocation.
That suspicion is now confirmed, following additional imaging by Peter Wakelin from the UK on May 8th. Still drifting when I picked it up on May 3rd, PAN now appears to have settled in a new position at 44.9 E, just west of Galaxy 27 and Intelsat 12. It has moved 2 degrees higher in my local sky, to an altitude of 19 degrees.
The identity of the second, flashing UNID, UNID-II which is still drifting westwards on May 8th, is still uncertain. While it is possibly the Indian communication satellite GSat-2 (03-018A) in the act of relocating, Space-Track still lists that object stable in its usual orbit slot placing it at 48 E. So we have something of a remaining mystery to solve there (although in the end, it will probably turn out to be Gsat-2, with Space-Track for some reason failing yet to recognize it is being moved).
UPDATE 09/05/2011: about an hour after I posted this, Space-Track updated the orbit for Gsat-2, showing that UNID-II is indeed Gsat-2, probably on it's way to the graveyard orbit. So, it appears I beat Space-Track to it by several days!
PAN (09-047A) has a history of frequent relocations, making this already enigmatic satellite the more enigmatic. Previous to this early May 2011 relocation, it relocated in early December 2010, an event that I was the first person to detect as well. So far, it has been located at 33.0 E from late 2009 to May 2010 and then was moved to 38.0 E; then to 49.0 E in December 2010; and now to 44.9 E in May 2011.
One, UNID-I, was stable in brightness. The other, UNID-II, was flashing. I imaged UNID-I the next night (May 4th) as well, showing it drifting westwards. I might have imaged UNID-II again too, though misidentifying it at that time as Intelsat 12 (except for the occasionally very bright UNID-II, the objects were, due to worse observing conditions, at the edge of detectability).
At that time (see the link above) there already was some suspicion that UNID-I could be the enigmatic classified geostationary satellite PAN (09-047A), caught in the act of yet another relocation.
That suspicion is now confirmed, following additional imaging by Peter Wakelin from the UK on May 8th. Still drifting when I picked it up on May 3rd, PAN now appears to have settled in a new position at 44.9 E, just west of Galaxy 27 and Intelsat 12. It has moved 2 degrees higher in my local sky, to an altitude of 19 degrees.
The identity of the second, flashing UNID, UNID-II which is still drifting westwards on May 8th, is still uncertain. While it is possibly the Indian communication satellite GSat-2 (03-018A) in the act of relocating, Space-Track still lists that object stable in its usual orbit slot placing it at 48 E. So we have something of a remaining mystery to solve there (although in the end, it will probably turn out to be Gsat-2, with Space-Track for some reason failing yet to recognize it is being moved).
UPDATE 09/05/2011: about an hour after I posted this, Space-Track updated the orbit for Gsat-2, showing that UNID-II is indeed Gsat-2, probably on it's way to the graveyard orbit. So, it appears I beat Space-Track to it by several days!
PAN (09-047A) has a history of frequent relocations, making this already enigmatic satellite the more enigmatic. Previous to this early May 2011 relocation, it relocated in early December 2010, an event that I was the first person to detect as well. So far, it has been located at 33.0 E from late 2009 to May 2010 and then was moved to 38.0 E; then to 49.0 E in December 2010; and now to 44.9 E in May 2011.
Thursday, 5 May 2011
[UPDATED] Two Unidentified Geostationary Objects on May 3 and 4
May 3 was an unusually clear evening, and I decided to target a few classified geostationary satellites, using the Carl Zeiss Jena Sonnar MC 2.8/180mm.
While imaging the region of PAN (09-047A) and Mentor 4 (09-001A), I found two unidentified objects. Yes: two.
The first object, UNID-I, was discovered close to the commercial geosats Galaxy 27 (99-052A) and Intelsat 12 (00-068A). It was present on multiple images, and the astrometry shows it is stable in declination. It was about as bright as the two commercial geosats, and stable in brightness.
The plot thickened, when a second unidentified object, UNID-II, was discovered just east of the first, just north of the commercial geostationary Syracuse 3A (05-041B). This object was irregular in brightness, alternating between faint and very bright (comparable to Mentor 4 at peak brightness, i.e. about mag. +8).
Below image shows UNID-I near Galaxy 27 and Intelsat 12:
The two images below show UNID-II near Syracuse 3A, and the clear flaring behaviour of the UNID.
On May 4th, the sky quality was poorer. Nevertheless I tried to recover the two objects, with partial success: UNID-II was captured again on several images.
It had drifted westwards, closer to Galaxy 27 and Intelsat 12 towards the position of UNID-I. The latter was not visible on the images, most likely due to the poor sky quality (Galaxy 27 and Intelsat 12 were barely visible either).
The object showed a clear variable brightness behaviour, being invisible in one image and very bright in the next one taken 30s later. Together with the slowly changing declination, this shows that the object is likely UNID-II, not UNID-I.
Below images were taken 30 seconds apart: the object is bright in one, and invisible in the other:
In the series of images, it is present in the following images:
from - to (UTC, May 4th)
---------------------------------------
21:03:02.30 - 21:03:12.35
21:04:02.30 - 21:04:12.35 - very bright
21:05:02.30 - 21:05:12.35
21:07:32.30 - 21:07:42.35
21:08:02.30 - 21:08:12.35
21:08:32.30 - 21:08:42.35 - very bright
21:11:02.30 - 21:11:12.35
21:12:02.30 - 21:12:12.35
21:13:02.30 - 21:13:12.35 - very bright
21:14:02.30 - 21:14:12.35 - very bright
---------------------------------------
As can be seen, there is a clear semi-1 minute periodicity in this.
I have no idea as to the true identity of these two objects. As I could find no trace of PAN (09-047A) near Yamal 202 on my May 3rd images, it is possible that UNID-I is PAN once again relocating.
The presence of a second, tumbling/spinning object, UNID-II, close to it however suggests that more is going on. Finding two UNID's close together is definitely weird and might suggest a connection between the two objects.
UNID-II has a small but clear inclination to it's orbit and appears to be drifting westwards. UNID-I is stable in declination, indicating an inclination close to zero. It might be drifting as well (only more observations will tell, given that I failed to find it on May 4th).
UPDATE 5-5-2011:
Ted Molczan feels UNID-II (the flashing one) could be the Indian commercial geosat Gsat 2 (03-018A) in the act of relocating. UNID-I could indeed well be, as I suggested in my report on Satobs, the classified geosat PAN (09-047A) relocating, according to Mike McCants. I captured the same satellite relocating in December last year: this enigmatic satellite is frequently on the move.
While imaging the region of PAN (09-047A) and Mentor 4 (09-001A), I found two unidentified objects. Yes: two.
The first object, UNID-I, was discovered close to the commercial geosats Galaxy 27 (99-052A) and Intelsat 12 (00-068A). It was present on multiple images, and the astrometry shows it is stable in declination. It was about as bright as the two commercial geosats, and stable in brightness.
The plot thickened, when a second unidentified object, UNID-II, was discovered just east of the first, just north of the commercial geostationary Syracuse 3A (05-041B). This object was irregular in brightness, alternating between faint and very bright (comparable to Mentor 4 at peak brightness, i.e. about mag. +8).
Below image shows UNID-I near Galaxy 27 and Intelsat 12:
click image to enlarge
The two images below show UNID-II near Syracuse 3A, and the clear flaring behaviour of the UNID.
click image to enlarge
On May 4th, the sky quality was poorer. Nevertheless I tried to recover the two objects, with partial success: UNID-II was captured again on several images.
It had drifted westwards, closer to Galaxy 27 and Intelsat 12 towards the position of UNID-I. The latter was not visible on the images, most likely due to the poor sky quality (Galaxy 27 and Intelsat 12 were barely visible either).
The object showed a clear variable brightness behaviour, being invisible in one image and very bright in the next one taken 30s later. Together with the slowly changing declination, this shows that the object is likely UNID-II, not UNID-I.
Below images were taken 30 seconds apart: the object is bright in one, and invisible in the other:
click image to enlarge
In the series of images, it is present in the following images:
from - to (UTC, May 4th)
---------------------------------------
21:03:02.30 - 21:03:12.35
21:04:02.30 - 21:04:12.35 - very bright
21:05:02.30 - 21:05:12.35
21:07:32.30 - 21:07:42.35
21:08:02.30 - 21:08:12.35
21:08:32.30 - 21:08:42.35 - very bright
21:11:02.30 - 21:11:12.35
21:12:02.30 - 21:12:12.35
21:13:02.30 - 21:13:12.35 - very bright
21:14:02.30 - 21:14:12.35 - very bright
---------------------------------------
As can be seen, there is a clear semi-1 minute periodicity in this.
I have no idea as to the true identity of these two objects. As I could find no trace of PAN (09-047A) near Yamal 202 on my May 3rd images, it is possible that UNID-I is PAN once again relocating.
The presence of a second, tumbling/spinning object, UNID-II, close to it however suggests that more is going on. Finding two UNID's close together is definitely weird and might suggest a connection between the two objects.
UNID-II has a small but clear inclination to it's orbit and appears to be drifting westwards. UNID-I is stable in declination, indicating an inclination close to zero. It might be drifting as well (only more observations will tell, given that I failed to find it on May 4th).
UPDATE 5-5-2011:
Ted Molczan feels UNID-II (the flashing one) could be the Indian commercial geosat Gsat 2 (03-018A) in the act of relocating. UNID-I could indeed well be, as I suggested in my report on Satobs, the classified geosat PAN (09-047A) relocating, according to Mike McCants. I captured the same satellite relocating in December last year: this enigmatic satellite is frequently on the move.
Sunday, 24 April 2011
More on the IGS 1B fuel tank, and the (reduced) risk of it re-entering
At the end of the previous weekend, I posted an extensive post on the malfunctioned Japanese spy satellite IGS 1B (03-009B). It malfuntioned in 2007, has subsequently lost orbital altitude, and is now expected to re-enter early 2012.
The concerns was, that it might have a still partly filled fuel tank - potentially creating a risk at re-entry, a concern similar to that for the re-entry of USA 193 in 2008 (which, for that reason, was destroyed on-orbit by a SM-3 missile). This greatly worried me, the more as no news on this was appearing from either the Japanese, or US Space Command (who no doubt must have been aware that IGS 1B was coming down - an object like this will certainly be tracked).
My assessment of a potentially still half-full tank, was, as I indicated, at best an "educated guess". Noted amateur observer Ted Molczan from Toronto has now made an independant assessment of the situation, notably on the absolute amount of fuel left. Below I quote from his analysis, in which he writes (after first noting that he gets similar results to mine as to the probable time of decay, i.e early 2012):
I have high trust in Ted's assessment: and the result is somewhat of a reassurrance: 14 to 50 kg of fuel is an order of a magnitude less than the 450 kg of fuel of USA 193. While no uncontrolled re-entry is without danger, these figures from Ted's assessment lead me to think that IGS 1B is clearly less of a threath than USA 193 was.
Ted's assessement is exactly the kind of thing I called for in my earlier post, when I wrote:
The concerns was, that it might have a still partly filled fuel tank - potentially creating a risk at re-entry, a concern similar to that for the re-entry of USA 193 in 2008 (which, for that reason, was destroyed on-orbit by a SM-3 missile). This greatly worried me, the more as no news on this was appearing from either the Japanese, or US Space Command (who no doubt must have been aware that IGS 1B was coming down - an object like this will certainly be tracked).
My assessment of a potentially still half-full tank, was, as I indicated, at best an "educated guess". Noted amateur observer Ted Molczan from Toronto has now made an independant assessment of the situation, notably on the absolute amount of fuel left. Below I quote from his analysis, in which he writes (after first noting that he gets similar results to mine as to the probable time of decay, i.e early 2012):
"I agree that IGS 1B could decay from orbit in 2012, with perhaps half of its initial fuelmass; however, I believe that its initial fuel mass probably was far less than that of USA193 - between approximately 28 kg and nearly 100 kg, compared with the 450 kg of USA 193. Ifhalf of IGS 1B's fuel has been expended, then between 14 kg and 50 kg may remain - at most10 percent of USA 193's fuel load. Only the Government of Japan knows for certain thequantity of fuel that remains, but if my estimate is in the ballpark, then the risk of anuncontrolled decay from orbit would be much less than for USA 193."
[...]
"USA 193 carried about 450 kg of fuel, none of which had been expended by the time of its impending decay, due to its failure soon after it reached orbit. I believe that IGS 1B may have considerably less fuel for the following reasons:
1. IGS 1B was designed to operate at a considerably higher altitude than USA 193 (485 km vs. 360 km), which means that it was subject to far less atmospheric drag, which would have decreased the quantity of fuel required for orbit maintenance.
2. IGS 1B's total mass is reportedly about half that of USA 193 (1200 kg vs. 2300 kg). For a given velocity change, the fuel expenditure varies in direct proportion to total spacecraft mass.
3. IGS 1B died four years into what was reportedly a five year mission, so might already have expended most of its fuel."
[note from Marco Langbroek: but its sister ship IGS 1A is still maintaining orbit 8 years later, as I indicated in my original post, suggesting that these satellites carry more fuel than for a minimum 5 year mission]
"With respect to points #1 and #2, assuming that IGS 1B's ballistic coefficient (mass divided by cross-sectional area) is similar to that of USA 193, and that its fuel supply was designed to enable operating up to twice the reported 5 year design life, i.e. 10 years, then the total velocity change required to maintain 485 km altitude would have been about 53 m/s (metres per second). Assuming IGS 1B uses the same fuel as USA 193, then for its mass of 1200 kg, the required initial fuel mass would have been just 28 kg - far less than that of USA 193.
Factoring in point #3: assuming provision of fuel for 10 years operation, then IGS 1B might have consumed 40 percent of its fuel by the time it died, four years after launch. Considering that its first couple of years of operation coincided with the tail end of the previous solar maximum, its fuel use could have been somewhat greater; assuming for the sake of argument that half its fuel has been expended, then 14 kg would remain.
I based this rough estimate on data found in the respected textbook/reference Space Mission Analysis and Design III, specifically the annual velocity change required to maintain low Earth orbits against decay, depending on altitude, ballistic coefficient and solar activity. I assumed that fuel for attitude control was negligible, and that IGS 1B was not designed to be de-orbited at the end of its useful life (the latter would have increased the initial fuel mass to nearly 100 kg, with perhaps 50 kg remaining after four years of operation, still far less than USA 193 carried.)"
I have high trust in Ted's assessment: and the result is somewhat of a reassurrance: 14 to 50 kg of fuel is an order of a magnitude less than the 450 kg of fuel of USA 193. While no uncontrolled re-entry is without danger, these figures from Ted's assessment lead me to think that IGS 1B is clearly less of a threath than USA 193 was.
Ted's assessement is exactly the kind of thing I called for in my earlier post, when I wrote:
Instead of watching this one quietly go down, I would prefer to see a good risk assessment done [...] a clear argument presented as to why it would not be a danger in this case, given all the fuzz created around falling fuel tanks with USA 193.Ideally, this should of course have come from the Japanese themselves (which refused to say anything pertinent to one of the reporters that contected me over this, besides the simple statement that there was "no risk"). In absence of that, Ted's assessment is a good thing to have.
Saturday, 23 April 2011
Yet another Japanese satellite failure!
The Japanese, already suffering from the major devastation of the recent earthquake, truely don't seem to catch a break.
Today news broke that yet another Japanese radar- and optical satellite has broken down on orbit. It concerns ALOS, a non-classified Earth Observation satellite including radar, visual and infrared sensing equipment.
This comes after the 2007 malfunction of the classified SAR satellite IGS 1B, which is now developing into a re-entry hazard concern for 2012 (as discussed extensively on this blog in a post from last weekend): and the 2010 malfunction of their other classified SAR satellite, IGS R2.
In the aftermath of the recent earthquake, losing their prized remote sensing satellites must really be a pain for the Japanese: this is all really at the most untimely of moments.
Unlike IGS 1B, ALOS is not a direct re-entry hazard for the near future. In a 697 x 694 km orbit (notably higher than that of the IGS-es), it will take a considerable time for it to decay.
Today news broke that yet another Japanese radar- and optical satellite has broken down on orbit. It concerns ALOS, a non-classified Earth Observation satellite including radar, visual and infrared sensing equipment.
This comes after the 2007 malfunction of the classified SAR satellite IGS 1B, which is now developing into a re-entry hazard concern for 2012 (as discussed extensively on this blog in a post from last weekend): and the 2010 malfunction of their other classified SAR satellite, IGS R2.
In the aftermath of the recent earthquake, losing their prized remote sensing satellites must really be a pain for the Japanese: this is all really at the most untimely of moments.
Unlike IGS 1B, ALOS is not a direct re-entry hazard for the near future. In a 697 x 694 km orbit (notably higher than that of the IGS-es), it will take a considerable time for it to decay.
Friday, 22 April 2011
KH-12 USA 129 flaring: and IGS 1B again
A period of sunny weather commenced the past week, albeit with a trend towards increasing hazyness. I observed on the 19th, 20th and 21st of April, targets being the evening KH-12's USA 129 (96-072A) and USA 186 (05-042A), as well as IGS 1B (03-009B). An attempt to locate the geostationary satellite Mentor 2 (98-029A) on the 20th failed, probably because of the poor observing conditions.
Yesterday evening (21st April) the sky was quite hazy with, during twilight, abundant whisps of thin clouds. USA 129 (96-072A) slowly flared to mag. 0 at about 19:56:15 UTC, and the resulting picture of the flare amidst thin clouds in a still bluish twilight sky, looks very eerie:
Some what later, I made this shot of IGS 1B (03-009B) gracefully sailing through Bootes:
My story about the re-entry of the above pictured malfunctioned IGS 1B satellite in about a year from now, has been picked up, notably after Jim Oberg reposted it on the NASA Spaceflight Forum here. Two journalists contacted me with questions, and my post itself attracted some US Government attention (when the Executive Office of the President visits your weblog, you know it is being taken serious). So I guess some people have woken up now, and hopefully we will soon see a serious risk assessment and more pertinent information by the Japanese as to the tank content of the satellite.
Yesterday evening (21st April) the sky was quite hazy with, during twilight, abundant whisps of thin clouds. USA 129 (96-072A) slowly flared to mag. 0 at about 19:56:15 UTC, and the resulting picture of the flare amidst thin clouds in a still bluish twilight sky, looks very eerie:
click image to enlarge
Some what later, I made this shot of IGS 1B (03-009B) gracefully sailing through Bootes:
click image to enlarge
My story about the re-entry of the above pictured malfunctioned IGS 1B satellite in about a year from now, has been picked up, notably after Jim Oberg reposted it on the NASA Spaceflight Forum here. Two journalists contacted me with questions, and my post itself attracted some US Government attention (when the Executive Office of the President visits your weblog, you know it is being taken serious). So I guess some people have woken up now, and hopefully we will soon see a serious risk assessment and more pertinent information by the Japanese as to the tank content of the satellite.
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