Why India's ASAT test was reckless (updated)

Today, I published a large article in The Diplomat:

"Why India’s ASAT Test Was Reckless. Publicly available data contradicts official Indian assertions about its first anti-satellite test"

The paper is online here: https://thediplomat.com/2019/05/why-indias-asat-test-was-reckless/

Summary - In this paper, I present an OSINT analysis of data available from Indian and US sources. From missile telemetry data visible in a DRDO released video (!) I reconstruct the last 2.7 seconds of the missile's trajectory relative to the trajectory of Microsat-R, showing that the missile hit the satellite under a clear upwards angle. I also discuss what can be gleaned from the orbital elements of the 84 debris pieces tracked so far.

The main conclusion is that the ASAT test was conducted in a less responsible way than originally claimed by the Indian government. First, the missile hit the target satellite on a clear upwards angle, rather than “head-on” as claimed by DRDO. Second and third, the test generated debris with much longer orbital lifetimes (up to 10 times longer), which ended up at much higher altitudes than the Indian government is willing to admit.

As much as 79 percent of the larger debris fragments tracked have apogee altitudes at or above the orbit of the International Space Station. Most of the tracked debris generated by the test orbits between 300 km and 900 km altitude, well into the range of typical orbital altitudes for satellites in Low Earth Orbit. As these debris fragments are in polar orbits, they are a potential threat to satellites in all orbital inclinations at these altitudes.This threat will persist for up to half a year (rather than the 45 days claimed by the Indian government), with a few fragments lingering on (much) longer, up to almost two years.


UPDATE, 2 May 2019:

On Twitter, I was asked to elucidate a bit more on how I did the analysis.

The delta V calculations have been done using equations from chapter 6 of "Space Mission Analysis and Design", third edition (Wetz and Larson (eds.), 1999).

The missile trajectory relative to the satellite trajectory was calculated with quite simple goniometry from the telemetry values (azimuth, range and elevation from the camera site) extracted from the DRDO video. Azimuth and range allow to calculate delta X, delta Y relative to the camera site on the flat reference plane. Elevation and range allow to calculate altitudes above the reference plane. AS the calculations are done with respect to a flat reference plane tangent to the earth surface at the camera location, this approach is sufficient. Earth curvature and true altitudes above the earth surface are irrelevant, a we are only interested in relative postions with regard to the satellite vector of movement.

First debris pieces from the Indian ASAT test of 27 March catalogued

click to enlarge

Today the first 57 orbital element sets for Microsat-r debris, debris from the Indian ASAT test on March 27, appeared on CSpOC's data-portal Space-Track (I have posted on aspects of this Indian ASAT test earlier: here, here and here). They have catalogue numbers 44117 - 44173. The analysis below is based on these orbital element sets.The elements confirm what we already knew: that Microsat-r (2019-006A) was the target of the ASAT test.

The image above plots the orbit of the 57 debris fragments, in red. The white orbit is the orbit of the International Space Station ISS, as a reference. Below is a Gabbard diagram of the debris pieces, plotting their perigee and apogee values against their obital period. The grey dashed line gives the orbital altitude of the ISS, as a reference:

click diagram to enlarge

Again, it is well visible that a large number of the 57 fragments (80% actually) have apogee altitudes above the orbit of the ISS, well into the altitude range of operational satellites. This again shows (see an earlier post) that even low-altitude ASAT tests on orbiting objects, creates debris that reaches (much) higher altitudes. The highest apogee amongst the 57 debris pieces is that of 2019-006AR at 2248 km.

Below is the apogee altitude distribution as a bargraph (including a kernel density curve), again showing how pieces do reach the altitudes of operational satellites:

click diagram to enlarge

Most of the created debris in the current sample of tracked larger debris has apogee altitudes between 400 and 700 km. It is interesting to compare this to a similar diagram for debris from the 2008 US ASAT demonstration on USA 193, "Operation Burnt Frost":

click diagram to enlarge

The Operation Burnt Frost debris distribution peaked at a somewhat lower apogee altitude, ~250 km (the same orbital altitude as the target, USA 193) while the peak of the Indian ASAT debris apogee distribution is higher, ~400-500 km (there could however be detector bias involved here).

It is interesting to note that both distributions appear to be double-peaked, both having a secondary peak near 700-800 km. I remain cautious however, as that could be due to detector bias.

Overall, the two distributions are similar, as I already expected.

The question now is, how long this debris will survive. To gain some insight into the expected lifetimes, I used Alan Pickup's SatEvo software to make a reentry forecast for the debris fragments. It suggests that most of the debris will stay on orbit for several weeks to months: by half a year from now, most of it should be gone however, except for a few lingering pieces. Note that this forecast should be taken with some caution: it assumes a constant solar activity at the current level, and takes the NDOT values of the element sets face value.

The following bar diagram charts the forecast number of debris objects reentering per week (the x-axis being the number of weeks after the ASAT test) resulting from the SatEvo analysis:

click diagram to enlarge

Again, the result is quite similar to the actual lifetimes displayed by the USA 193 debris fragments after Operation Burnt Frost in 2008 (see an earlier post, with the same diagram), as expected:

click diagram to enlarge

Why even low altitude ASAT intercepts are a threat to operational satellites in higher orbits

Click diagram to enlarge. Orbital data from CSpOC

So how big a threat is this Indian Anti-Satellite (ASAT) test of 27 March to operational satellites at higher altitudes, given that it was performed at relatively low altitude (283 km, see an earlier post)?

In an earlier post, I noted that the US ASAT demo on USA 193 ("Operation Burnt Frost") in February 2008 was a good analogue (read here why). Like the March 27 Indian ASAT test on Microsat-r, the USA 193 ASAT demonstration happened at relatively low altitude, even lower than the Indian test: 247 km. So where did debris from that test end up, altitude-wise?

The diagram above is a so-called "Gabbard Diagram" which plots apogee and perigee altitudes of individual debris fragments from the 2008 USA 193 intercept against their orbital period. (apogee is the highest point in its elliptical orbit, perigee the lowest point). The diagram can be of help to show insight into how high fragments are ejected in an ASAT test. Please do note that it concerns a subset of well-tracked larger fragments: most of the smaller fraction of debris, difficult or impossible to track, is absent from this sample.

As is visible in the diagram, many fragments ended up being ejected into highly eccentric ("elliptical") orbits with apogee, the highest point in their orbit, well above the intercept altitude. Many ended up with apogee altitudes well into the range of operational satellites (typically 400+ km).

I have indicated the International Space Station (ISS) orbital altitude (its current perigee altitude at ~407 km, not that of 2008) as a reference. Some 64% of the larger fragments in the pictured sample ended up with perigees apogees (well) above that of the ISS. Quite a number of them even breached 1000 km altitude.

This makes clear that even low altitude ASAT tests generate quite some debris fragments that can endanger satellites at higher altitudes. True, most of it reenters within hours to a few days of the test, but still plenty remain that do not. In my earlier post I showed the orbital lifetime of these same fragments from the USA 193 ASAT demonstration. Many survived on orbit for several weeks to months, occasionally even up to almost two years after the test:

click diagram to enlarge

So it is clear that a "harmless" low altitude ASAT test on an orbital object does not exist (note that I say orbital and not sub-orbital). Every test generates a threat to satellites at operational altitudes. Hence NASA administrator Bridenstine was quite right in his recent condemnation of the test. It is indeed very likely that debris fragments ended up in orbits with apogee at or above the orbital altitude of the ISS and other operational satellites in Low Earth Orbit.

Analysis: The re-entry of the CZ-4B r/b 2014-049C observed by a Dutch pilot on May 27 [UPDATED]

click to enlarge. Image (c) Christiaan van Heijst, used with permission

click to enlarge. Image (c) Christiaan van Heijst, used with permission

The beautiful, spectacular images of a rocket stage re-entry above were made by the Dutch aviation photographer and pilot Christiaan van Heijst,  the co-pilot of a Cargolux freight aircraft (flight CV760, a Boeing 747-8 with registration LX-VCC) en route to Brazil on May 27, 2017.

While cruising at FL 340, 34 000 feet (10.360 km) over the mid-Atlantic, Christiaan noted a group of 7 to 10 bright yellow, very slow fireballs appearing in the corner of his eye. Here is the story as told by Christiaan on his facebook page:

Suddenly I noticed something in the corner of my eye. I looked to my right and to my own surprise I saw a huge group 7-10 of bright yellow lights move parallel to our track with a much faster speed and very high altitude. This was not an airplane, nor was it a meteorite. Where shooting stars / meteorites often leave a bright trail, they move with very high speed and burn up quickly. This cluster of lights moved far too slow to be a meteorite and its light was far too constant to be an ordinary meteorite. 

Immediately, a lot of excited chatter in Portuguese and other (African) languages I could not identify. was opening up on the frequency we had tuned in. Apparently lots of pilots were seeing the same lights, which is not surprising with such a high and bright appearance. All in all, the lights appeared abeam our aircraft and disappeared on the horizon in roughly two minutes time, keeping their intensity and appearance along the way.

Evidently, what Christiaan and his colleagues were witnessing was a spectacular re-entry of space debris, with the re-entering object breaking up in multiple pieces while it was plunging through the atmosphere. The time of this re-entry event was around 23:18 UT on May 27, 2017, while the aircraft was over the mid-Atlantic near 11^o.93 N, 33^o.28 E (see also later in this post).

In this blog post, I identify the object responsible and provide some model results for this re-entry.

click map to enlarge

Christiaan van Heijst initially thought that this re-entry event was related to a NOTAM issued mid-May, a warning for the splash-down of a Soyuz 2nd stage during the SES-15 launch from Kourou. This launch however had already happened 10 days earlier, on May 18, so evidently was no explanation for this event. Christiaan next posted his story on Facebook, hoping that someone could identify the object responsible.

I was allerted to Christiaan's Facebook post by one of my Twitter followers, Theo Dekkers and could quickly identify the event as the re-entry of 2014-049C, a Chinese Chang Zheng (Long March) 4B (CZ-4B) upper stage from the launch of the Chinese Gaofeng 2 and Polish Heweliusz satellites in August 2014. Time, location, and movement of the witnessed event agree extremely well.

Two days before the sighting, JSpOC had started issuing TIP (Tracking and Impact Prediction) messages for this object via their Space-Track portal. The final TIP message, issued after the actual re-entry, lists the re-entry time as 27 May 23:17 +- 1 min UT, near 15^o.7 N, 34^o W (by the way: we actually believe that such times accurate to 1 minute originate from infrared observations of the re-entry fireball by US SBIRS early warning satellites).

click to enlarge

This time and position closely agrees with the observations of the aircraft crew and the aircraft position. Christiaan van Heijst provided me with a photo of the aircraft flight instruments taken about one minute after the event. It shows the time of that moment, 23:20:43 UT, and the aircraft's GPS coordinates and altitude: 11^o 56.1' N (11.935 N), 33^o 17.3 W (33.288 W) at a flight level of 34 000 ft (10.360 km). [edit: the altimeter in the image above says 33 960 feet but Christiaan informed me that it has a small error and they were flying at FL 340]. The aircraft was heading towards a magnetic bearing of 219 deg, which corresponds to a true bearing of 204 degrees (towards the S-SW).

The time and position are very close to that of the TIP: a difference of about 425 km between the TIP re-entry location and the location of the aircraft, and 1-2 minutes in time.

The sky track of the re-entering space debris that can be seen on the photographs also agrees well with the predicted sky track of 2014-049C for the aircraft's location. Below is the predicted track for 2014-049C for the location of the aircraft based on a propagated version of the last available orbital element set for the object. The blue line is the predicted track in the sky, the yellow arrow the approximate trajectory for the brightest fragment visible on Christiaan's photographs:

click to enlarge

There is a discrepancy, in that the observed trajectory is some 11 degrees lower in the sky than the predicted trajectory, with a time lag as well. However, this is what you expect. The track shown is for the pre- re-entry orbital altitude (about 134 km). During the re-entry phase, the altitude of the object however quickly drops, and as a result the observed track will be located significantly lower in the sky. As the object is slowed down by increasing drag of the atmosphere, it starts to lag behind predictions in time as well. At the time of the re-entry, the object was already below 80 km altitude,  40% or more below its orbital altitude.


[UPDATE  6 Oct 2017:]

I have since used the output of a GMAT re-entry model (see below) to reconstruct the expected trajectory in the sky as seen from the aircraft. For this purpose, I used the latitude, longitude and altitude output of the GMAT model, converted these to ECEF coordinates, did the same for the position of the aircraft, and then with the help of relevant equations calculated the azimuth and elevation of the reentering rocket stage as seen from the aircraft from these. The sky positions were plotted on a star map for the location of the aircraft. The result is below (compare to the two photographs in top of this post):

click map to enlarge

As can be seen, the modelled sky trajectory, while not a perfect fit, is nevertheless very close to that visible on the photographs.

Note that the GMAT reentry model, while modelling the influence of the atmosphere, does not take fragmentation and ablation (and from that mass-loss and changes in surface:mass ratio) into account.

[END OF 6 Oct 2017 UPDATE]

To gain insight into the positions and altitude of  the re-entering debris over time relative to the aircraft, I have modelled the re-entry event. I propagated the last five known orbital element sets (TLE) for 2014-049C to its last ascending node passage before re-entry, using SatAna and SatEvo. The resulting, final, pre- re-entry TLE was next used as the starting point for a ballistic simulation in GMAT, using the MSISE90 model atmosphere and actual Space Weather data. With this input, I had GMAT calculate positions and altitudes of the re-entering object over time.

Such modelling always is an approximation only. There are a number of unknowns, one of which is the spatial orientation of the major axis of the re-entering rocket stage with regard to its flight direction. This adds uncertainty to modelling the atmospheric drag experienced by the re-entering rocket stage, which introduces uncertainties in the position and altitude of the stage for a certain time. A CZ-4B 3rd stage is a tube measuring 6.24 x 2.90 meter with a dry mass of about 1 metric ton. The drag experienced depends on whether its longest dimension is facing the flight direction, its narrow end, or whether it tumbles. For the modelling, I choose to use a drag surface that is 50% of the maximum drag surface possible. Breakup of the rocket body, which is evidently happening (see the copious fragmentation in the photographs) adds more uncertainty, as fragmentation drastically alters the drag surface and surface-to-mass ratio. As the images show, the trajectories of individual fragments clearly start to diverge as a result of this. The model, however, treats the re-entering body as one single body with no mass loss.

So, Caveat Lector. But let us look at the results. Mapping the GMAT results along with the position and bearing of the aircraft a minute after the event, yields this positional map and this altitude versus time profile:

click map to enlarge

click diagram to enlarge

For the reasons mentioned above, the altitudes versus time in the diagram are approximations only, with a possible uncertainty of perhaps 25% for a given time instance.

Compared to the JSpOC TIP data, the resulting trajectory I modelled seems to be slightly on the 'early' side, in that it passes the JSpOC location about a minute too early. On the other hand, the time in the TIP is given with an accuracy of no better than 1 minute, and an unspecified inaccuracy in the coordinates of the geographic location as well. What we can conclude from the modelled positions relative to the aircraft, is that the sighting definitely matches the 2014-049C re-entry data closely.

If my modelling is somewhat correct, the re-entering debris was moving from altitudes of ~95 km at the start of the sighting to below 50 km near the end [update 6 Oct 2017: The closest it came to the aircraft was a line-of-sight minimum distance of 157 km near 23:16:50 UT]. It is uncertain whether anything survived to sea level c.q. aircraft flight level. Usually, most materials have burned up before they could reach the surface: it is however not impossible that some pieces nevertheless survived and splashed down in the Atlantic. Notably the pressure spheres of rocket engines tend to survive. If anything, the modelling shows that any surviving debris was well ahead of the aircraft once it reached the flight level of the aircraft.

Ted Molczan has done a similar modelling with similar results. The differences that do exist between Ted's analysis and my results, are due to the choice of slightly different starting parameters for the model.

The final spectacular demise of 2014-049C was the result of a long drop that started short after launch. Below I have mapped the evolution of the orbital altitude of the rocket booster over the past years, starting just after launch:

click diagram to enlarge

The quick decay of (notably) the apogee altitude, but also perigee, can be clearly seen. Early 2017, the drop in altitude starts to increase exponentially. At 23:17 UT on 27 May 2017, after 15772 revolutions around the planet since launch, it was the final end for 2014-049C.

Christiaan asked me why there was no NOTAM issued for this re-entry. NOTAMS or Area Warnings are however generally only issued for controlled de-orbits, and first and second stage splashdowns during launches. Reasonably accurate locations can be predicted in advance for these. For uncontrolled re-entries, such as this event, this is not the case. There are so many uncertainties that anything approaching an accurate prediction can only be issued during the last hour or so before re-entry.

(note 1: for some Frequently Asked Questions about re-entries, see an earlier post here).
(note 2: this post was updated on 6 October 2017 to add some new modelling results)

Acknowledgement: I thank Christiaan van Heijst (www.jpcvanheijst.com) for providing extra information and for his permission to use his photographs. I thank Theo Dekkers for pointing me to Heijst's observations.

VIDEO: the ISS Fabric Shield (again), and North Korea's Kwangmyongsong-4

Yesterday I posted April 3 photographic imagery of the ISS Fabric Shield (1998-067 LF), a 1.5 x 0.6 meter anti-micrometeoroid shield astronauts inadvertently let fly into space during an EVA on March 30 (see my previous post for more details).

Yesterday evening April 4, in late twilight, I managed to film the object, which was now 1m 45s ahead of the ISS. The video, shot with a WATEC 902H low-light-level camera and a Samyang 1.4/85 mm lens, is above.

Later in the evening I also targetted  North Korea's Kwangmyongsong-4 (KMS-4, 2016-009A) which I had filmed, but as a very faint object, a week before as well. This time, KMS-4 was much brighter due to a more favourable illumination angle, and is easy to see as it cruises past Alcor and Mizar:



Both the ISS Fabric Shield and KMS-4 do not show a clear periodic brightness variation in the video imagery. The only variation that is there are slow trends (altitude and illumination angle related) and fluctuations within the fluctuation expected from atmospheric scintillationand oscillations in the video signal (estimated by looking at variations in the apparent brightness of a comparison star) :

click diagram to enlarge

The ISS Fabric Shield accidentally released from the ISS imaged in orbit

On March 30, 2017, NASA astronauts Shane Kimbrough and Peggy Whitson conducted an EVA from the International Space Station to prepare a new docking port and install new equipment on the outside of the ISS.

click to enlarge

During this spacewalk, they accidentally released a 1.5 x 0.6 meter large protective Fabric Shield, a shield against micrometeoroids that was one of four to have been installed that day on one of Tranqility module's ports. Somehow it got loose  and floated away in space, before the astronauts were able to retrieve it. Oopsy!

Once floating free in space, and having become space debris, it was catalogued by JSpOC as object nr. 42434, 1998-067LF.

The image above shows the shield, imaged from Leiden last night during a zenith pass with an 1.4/85 mm lens. It is faint and was almost exactly a minute in front of the ISS. It seemed steady in brightness on the 3 images I obtained (spanning an arc of 15 seconds in time).

Here is a screencap of the moment the object floated away during the EVA, somehow having come loose of its tether:

click to enlarge

The image below shows the ISS, a minute later (bright stars are kappa and iota UMa):

The accidentally released Fabric Shield has a relatively large surface relative to its weight [added edit: it weights 8 kg and measures 1.5 x 0.6 meter], which means it will quickly decay and re-enter, probably within 5 to 6 months from now.

Chinese CZ-11 rocket stage impacts Myanmar Jade quarry (updated)

On November 9 at 23:42 UT (November 10 in local time), China launched a Long March 11 (CZ-11) rocket from Jiuquan on a south-bound trajectory, lofting the XPNAV satellite into orbit.

The object (image from the Myanmar Times)

Shortly after this, an object came crashing out of the sky in Myanmar, impacting in a Jade quarry near Hmaw His Zar village near Hpakant in Kachin Province. Photographs of the object can be seen in the news stories here and  here. The image in the first link is the best in terms of showing shape and size.

The object is reportedly ~4 meter long and ~1.5 meter wide (reports differ slightly). In one of the images, it is clear that it is different in diameter at both ends, the shape being that of a barrel with a tapering segment on it.

Size and shape conforms to (what I assume is) the second stage of the CZ-11 (edit: might in fact be the 3rd stage), which is about ~4 meters long and about 2 meter diameter at one side, tapering to about 1.4 meter diameter at the other side. A drawing of the rocket's elements is here and another, perhaps more accurate rendering is here (the drawings differ somewhat, hence my confusion on whether this is the 2nd or 3rd stage. From the second rendering, it looks to be the 3rd rather than the 2nd stage).

Click map to enlarge

As can be seen in the map above, last Wednesday's Chinese launch trajectory lines up well with the reported location of the impact in Myanmar.  So it almost certainly is the 2nd (3rd?) stage of the CZ-11 rocket used for this launch.

[edit 12 Nov 2016: to be clear, the line on the map is a projection of the orbital plane of the XPNAV satellite at the moment of launch, as a proxy for the launch trajectory. You can see it lines up with both the Jiuquan launch location and the location where the object came down in Myanmar].


UPDATE: Jeffrey Lewis ("The Arms Control Wonk") pointed me to this Chinese CNTV footage about the recent launch that shows various parts of the CZ-11 rocket. From 0:35 onwards, one of the stages shown visually clearly is a match for the Myanmar objects:



Here are a few stills from the footage, compared to one of the images of the Myanmar object. The red semi-transparent boxes indicate which stage matches in terms of shape and details such as the round hole halfway the hull:

click to enlarge

(editted 12 Nov: added images and text, noted the 2nd/3rd stage potential confusion)

The tumble periodicity of the Chang'e 3 upper stage (2013-070B) revisited

click image to enlarge

Brightness variation due to tumbling of the Chang'e 3 upper stage (2013-070B)
stack of 15 images taken with the 0.51-m telescope of MPC Q65 Warrumbungle
11 September 2015

I have written before on this blog about tracking very distant space debris: the CZ-3C upper stages of the Chinese Lunar missions Chang'e 2 and Chang'e 3, which move in chaotic trans-Lunar orbits. I have embarked on a long-term project to follow these objects.

Apart from positions to keep their orbits up to date, these observations also provide information about the tumbling behaviour of these objects. Both objects have a periodic variation in brightness: a very rapid one for 2010-050B, the Chang'e 2 upper stage, and a slow one for 2013-070B, the Chang'e 3 upper stage.

Earlier, in July 2015, I had established a tumbling periodicity of  ~7 minutes for 2013-070B. I have now been able to refine that value much better, to only a few hundreds of a second.

With the help of Peter Starr from Warrumbungle Observatory (MPC Q65) in Australia and Krisztián Sárneczky from Szeged University's Piszkéstető Observatory (MPC 461) in Hungary, I could obtain two nice series of data the past week. The data were gathered on September 11 (Warrumbungle 0.51-m telescope) and September 14 (Piszkéstető 0.60-m Schmidt telescope).

The first set, taken by Peter from Warrumbungle, is a set of 15 exposures of 30 seconds each, taken in ~1 minute intervals. The image at the top of this post is a stack of these images. The brightness maxima can be clearly seen.

The second set, obtained in twilight by Krisztián from Piszkéstető at the end of a run of the Szeged Asteroid Survey, is a set of 18 exposures of 3 seconds (!) each, in ~20 second intervals, with a brief pause halfway the series.

Single sinusoid fit to data from Sep 11 (lef) and Sep 14 (right)
click diagram to enlarge

The data allow to fit a sinusoid to both sets simultaniously, and from that get a very accurate periodicity. The double diagram above shows this sinus-fit to the data. It allows to establish a peak-to-peak periodicity of 423.01 ± 0.03 seconds for the tumbling of 2013-070B.

Tracking distant space debris: more Chang'e 2 r/b observations

In my previous post I related how on May 7 a distant piece of Space junk was briefly mistaken for a Near Earth Asteroid. It concerned 2010-050B, the upper stage of the Long March 3C rocket that launched the Chinese Lunar mission Chang'e 2 in October 2010. This upper stage is moving in a trans-Lunar orbit, with apogee up to almost two Lunar distances away from Earth. The rocket stage is 12.4 by 3 meters large.

Yesterday May 10, I obtained new images of the object, using the 0.61-m Cassegrain telescope of Sierra Stars Observatory in California, USA. Above is an animated GIF of the images. My resulting astrometric data are here.

The object was near mag. +15.3, at a distance of almost 518 800 km at that time. For a comparison: the distance to earth of the moon varies between about 356 400 and 406 700 km. It is quite cool to image space junk at this large a distance!

Click image to enlarge

Using my May 10 observations combined with the May 7 observations by the Catalina Sky Survey (MPC 703) and Peter Starr in Warrumbungle (MPC Q65), I compute the following orbit for the object:

Orbital elements: 2010-050B Chang'e 2 r/b

Perigee 2015 May 22.689019 +/- 0.00747 TT 
= 16:32:11 (JD 2457165.189019) 
Epoch 2015 May 7.0 TT = JDT 2457149.5       Find_Orb 

M 198.75910 +/- 0.037        
n 10.27730942 +/- 0.00562

a 452220.817 +/- 165 km    Peri. 151.22410 +/- 0.028 
e 0.2197903 +/- 0.000308   Node 226.29285 +/- 0.00006
i 41.13389 +/- 0.00028 
  
q 352827.032 +/- 267 km    Q 551614.602 +/-  68 km       
P 35.03 d        H 28.1 

From 23 observations 2015 May 7-10; mean residual 0".307.

In TLE form:

Chang'e 2 r/b                                 352827 x 551615 km 
1 00000U         15127.00000000  .00000000  00000-0 00000-0 0 09
2 00000 41.1326 226.5090 2163618 150.9650 199.0248 0.02835833 01

For those people with access to a  sufficiently large instrument that want to try it themselves: efemerids for the object can be obtained here.

I plan to include this object in my periodic observations of distant satellites.

An 'asteroid' that wasn't: the Chinese Chang'e 2 upper stage (2010-050B) imaged at almost twice the Lunar distance

WJ297AD = Chang'e 2 r/b. Images (c) Peter Starr, Australia

On 7 May 2015 near 7:35 UT, the Catalina Sky Survey (MPC 703) in Arizona detected a bright mag. +17  fast moving object moving at about 12"/minute through Virgo. The object was reported as a potential Near Earth Asteroid and entered the NEO Confirmation Page (NEOCP) of the IAU's Minor Planet Center with temporary NEOCP designation WJ297AD.

Some 6 hours later, Peter Starr at Warrumbungle Observatory (MPC Q65) in Australia targetted the object with his 0.51-m Dall-Kirkham telescope, in order to confirm it and obtain more positions.

As he often does with NEOCP objects he images, Peter sent the imagery to me for astrometric processing.

image (c) Peter Starr. Click image to enlarge

After I measured the images (a part of one is shown above, showing the object as a short trail amidst the stars) and tried to fit an orbit to the astrometry obtained from Peter's images and the Catalina Sky Survey observations, the result was odd.

FindOrb suggested that this object was in orbit around the Earth, in a trans-lunar orbit with perigeum at  352 666 +/- 426 km, apogeum at 552 356 +/- 934 km, an orbital inclination of 41 degrees and an orbital period around the Earth of 35 days! The MPC itself, fitting several preliminary orbits, also presented solutions pointing to an object in an odd, very earth-like orbit with semi-major axis about 1.05 AU and a heliocentric orbital period of ~1.0 year.

At that time, after an initial "Huh? That's odd..." I already developed some feeling that this might perhaps be an artificial object, if this fit was not spurious. I was not sure though (preliminary orbit fits to small observational arcs can come out weird on occasion), so I sent Peter an e-mail mentioning that it was a "weird object that seems to be in a very Earth-like orbit".

Meanwhile, another asteroid observer, Jacques Cristovao, also thought that this NEOCP object was odd. Around the time Peter was doing his observations from Warrumbungle, Cristovao suggested in a message on the Minor Planet Mailing List that the object was artificial, and specifically was 2010-050B, the upper stage of the Chinese Chang'e 2 Lunar probe.

That turned out to be correct: WJ297AD indeed is the rocket stage from this launch.

This rocket stage moves in a very wide translunar orbit with perigeum close to one lunar distance, and apogeum at almost twice the Earth-Moon distance. At the time of the observations it was near apogee at a distance of about 535 500 km, well beyond the moon at almost twice the Earth-Moon distance.

Chang'e 2 orbit in the Earth-Moon system (based on May 7 observations)

The rocket stage was used to bring the second Chinese Lunar mission, Chang'e 2, into a temporary orbit around the moon. Chang'e 2 itself later left the Earth-Moon system for a journey to asteroid Toutatis, but the rocket stage it left behind is still in orbit around the Earth-Moon barycenter.

It was not the first time that the Chang'e 2 rocket  was initially confused with a Near Earth Asteroid. The same happened in 2013 when the rocket was briefly known as 'asteroid' 2013 QW1.

These days, even the asteroids are Made in China....

[UPDATED] Re-entry of Soyuz third stage 2014-074B from Soyuz-TMA 15M launch observed from the Netherlands and Hungaria.

Update 23 Dec 2014: further analysis of imagery in new post
(28 Nov 2014, 10:45 UT: updated with more imagery)

click image to enlarge

Today Carlos Bella alerted the seesat list that Hungarian amateur astronomers had captured imagery of a re-entry in the early morning of November 26.

It concerns the re-entry of 2014-074B, the Soyuz third stage from the launch of Soyuz-TMA 15M which launched expedition crew 42 to the ISS on 23 November 2014.

Below is one of several casual phone-camera video's also shot from Hungaria Serbia, showing the fragmenting fireball:

(video by Aleksandar F, Belgrade)

According to the TIP message of  JSpOC, the re-entry happened near 3:39 UT on the early morning of 26 November, 2014, near 47 N,  17 E. This perfectly fits the Hungarian observations. See also the map above, which shows the predicted trajectory of 2014-074B resulting from processing the last known orbital elements with SatAna and SatEvo.

Moreover, the speed determination by the Hungarian meteor camera network, 7.4 km/s, confirms this is not a meteor but a re-entry. The speed is too low for a meteor (which are always faster than 11.8 km/s, the earth escape velocity) but matches the speed of an object re-entering from Low Earth Orbit.

Realizing that the rocket stage made a pass over the Netherlands/Belgium only minutes earlier,  I asked the operators of the DMS All-Sky meteor cameras to check their imagery of that morning. As it turns out, three Dutch All-sky stations did capture the re-entry: Bussloo (Jaap van 't Leven), Oostkapelle (Klaas Jobse) and Ermelo (Koen Miskotte).
 

Detail of the Bussloo Public Observatory all-sky image (courtesy Jaap van 't Leven)

Detail of the Cyclops Oostkapelle all-sky image (courtesy Klaas Jobse)

Detail of the Ermelo image (courtesy Koen Miskotte)

Parts of the three Dutch images (courtesy Jaap van 't Leven, Klaas Jobse and Koen Miskotte) are shown above. All stations have it very low above the horizon at elevations of 20 degrees or lower.

The Oostkapelle image shows that the incandescent phase of the re-entry already started over the UK, as the image shows the trail well to the west (and Oostkapelle is on the Dutch West coast).

As soon as I can find some time, I will analyze the imagery to see whether I can get altitude data from them. It would be nice to document the last minutes of this rocket stage in this way!

So stay tuned for an update....

UPDATE 23 Dec 2014: new post with a further analysis with trajectory and altitude reconstructions based on observations from the Netherlands, Hungaria and Germany now available. 

(I thank Jaap van 't Leven, Klaas Jobse and Koen Miskotte for permission to use their imagery)

[UPDATED & CORRECTED] Observing the SpaceX Dragon CRS-3, the ISS and two pieces of Dragon launch debris

CORRECTION (21/04/2014 12:55 UT): in the initial post, the two debris pieces were misidentified. "2014-022C" turned out to be 2014-022H, and "2014-022H" turned out to be 2014-022G.

click image to enlarge

Last Friday at 19:25 UT, SpaceX launched the Dragon CRS-3 commercial supply ship to the International Space Station ISS. It passed over Europe 20 minutes later but unfortunately I was clouded out in Leiden. In the middle and eastern parts of the Netherlands as well as elsewhere in Europe, observers were treated to a spectacular view of the Dragon, the Falcon upper stage, and two faint pieces of debris passing by as a thight group of objects.

SpaceX Dragon CRS-3
click image to enlarge

I was more lucky yesterday when the sky was clear and the Dragon and ISS made a late twilight pass culminating at approximately 26 degrees altitude in the SW near 20:06 UT (22:06 local time, sun at -12 deg.). The image above shows the Dragon CRS-3 due south already somewhat past culmination. It was easy to see with the naked eye, attaining magn. +1.5. Its brightness is more similar to a Progress or ATV then to the much fainter commercial Orbital Sciences Cygnus.

The Dragon was about 1m 12s behind the ISS, a visual distance of somewhat over 40 degrees. Pre-observation predictions based on elements a few hours old had put it in front of the ISS, so at first I was wondering whether I missed it. Then, as the ISS was descending towards the SE, I saw it approaching in the SW, chasing the ISS. A very fine sight!

The ISS passing the same sky area as the

earlier image, 1 min earlier

(click image to enlarge)

While I was photographing at the nearby city moat, I had also set up the video in my girlfriend's appartment, and this capture both objects as well: first the ISS, then a minute later the Dragon:




(the display says "GPS BAD" because my GPS time inserter failed to lock on a GPS satellite. I hope it is not broken...)

Apart from the Dragon and the ISS, I observed and photographically imaged a third debris object related to the launch. It is the object catalogued by JSpOC as 2014-022C/#39682. 2014-022H, #39687. It is either the jettisoned Dragon nose cone cover, or one of the solar panel covers   or possibly one of the Nanosat dispensers: I think it is too bright to be one of the several released nanosats itself. It was faint and slowly tumbling, alternating between invisibility and a max magnitude of about +3.5:

tumbling Dragon debris 2014-022H

(click image to enlarge)

[UPDATE:] Later I discovered a second piece of Dragon CRS-3 launch debris on my imagery. It is faint, irregular in brightness and present on two images, the best of which is this one from 20:04:07 UTC:

tumbling Dragon debris 2014-022G
(click image to enlarge)

This turns out to be the object designated 2014-022H, #39687  2014-022G, #39686. This is the other solar panel cover.

The "Piece of MIR" that quite probably isn't

During the previous weekend, a story appeared in several news outlets (e.g. here and here and here) in which a man from Amesbury, Massachusetts, claims to have found a strange rock in a riverbed which "NASA" (according to the story) next identified as either a piece of the Russian space station MIR or a piece of "MIR era space debris" (the latter depending on the news outlet).

MIR was a Russian Space Station, in many ways the fore-runner of the ISS, which was de-orbited in March 2001.

While the story was quickly and uncritically proliferated by several news outlets (even RIA Novosti), many space and satellite buffs (including this blog's author) were suspicious of the claims right away. The object, a glassy piece of rock, looked nothing like a genuine piece of space debris. And the specific link to MIR or a MIR-era Russian spacecraft seemed dubious in the absence of a recognizable machine part morphology or machine part registration number.

Here are a couple of pictures of the object, which are screenshots from the CBS Boston video news report here:

The man who reportedly found it, claims he picked it up from the mud at low tide several years ago at a point where his backyard touches on the banks of the Merrimack river. It was a greenish glassy rock "covered in mud".

He put it under a tree in his yard where it sat for several years until his sister in law, who knew someone at NASA, sent it to that person for analysis. Or so the story goes. Many months later, the object was returned with a letter purporting to be from a NASA engineer called "George Leussis". In this letter it was identified as "a piece of MIR" or ballast from a MIR-era Russian spacecraft.

But is it? To be frank: most likely it is not.

First of all, while ballast is sometimes indeed added to space launches (to let the launch mass match the rocket performance), this is not in the form of rock. Such ballast is usually water (in a tank), sand, or metal. And glass is not a major component of spacecraft (glass fiber is though). Certainly not in seizable chunks.

More important than that: what are the reasons to think this is space debris in the first place? It doesn't look like a part of a spacecraft at all. It looks like a glassy rock.

The piece looks like a silicate glass, with clear signs of weathering (e.g. the pitting on the surface, the dull glossy shine), and clear conchoidal flaking (best seen on the third picture above).  Contrary to the impression given by the news reports, I can see no evidence of a "fiery entry through the atmosphere" on the pictures of the piece. It looks like a smelt alright, but contrary to what many people think that is not what you get from an atmospheric reentry. Pieces will ablate and will get a thin fusion crust (thin melt layer) just like meteorites, but they do not melt completely and next solidify into a clump again.

The conchoidal fracturing certainly would have to have taken place after any melting, and given that the flaked surface has the same green-brown colour there, the latter colour is certainly not due to any superficial burning.

To be honest the object looks very much like either one of two things (which can look quite alike on photographs, since both are silicate melts):

1) a piece of  obsidian (volcanic glass);
2) a piece of industrial silicate slag.

The first is a natural material: the second is man-made waste. Both basically consist of solidified clumps of glass and often have a dark blackish, greyish, brownish or greenish colour. They can show flow lines in the glass, vesicles, and are subject to weathering phenomena that include surface pitting from dissolution. All of which can be seen on the pictures of the object in question.

So what actually traces this clump of silicate melt to the Russian space program rather than a more earthly origin? The short answer: apparently nothing.

A molten silicate is not unique to products of the Russian space program. In fact it is not likely to be a product of any space program. It is very ubiquitous on earth as industrial waste, as volcanic product etcetera. Only if a geologist can ascertain the object is none of those, then one can think of another, more wilder and rare origin - such as Russian space "ballast". Note that none of the news stories mentions a geologist looking at the object - they only mention a NASA engineer (but: see below!).

The next claim in the story is the specific link to the Russian space program (rather than space debris in general) - Mir or Progress. In the absence of a recognizable morphology or a machine part number, this link is completely uncorroborated.

At the least, I would like to see a clear chemical analysis with an argument why the composition would uniquely point to the Russian space program, as opposed to a common terrestrial origin (i.e. an industrial slag or a volcanic glass).

The letter quoted in one of the news articles claims such, but in vague and  ambiguous wording. It seems to say the material is terrestrial, and only the "green colour and strange properties" according to the letter point to it having been "subjected to a fall from low Earth orbit". The green colour is however certainly not unusual for industrial silicate slag and volcanic glass, and I see no "strange properties" in the published images of the rock nor the descriptions of the rock that would point to it having experienced an atmospheric entry (or would be unusual for an industrial silicate slag or volcanic glass). Moreover: the apparent "letter from NASA"  has since come under suspicion.

For here is the clincher: it is claimed that the identification was made by a NASA engineer called George Luessis. An engineer called George Luessis indeed works for NASA (he was part of the Chandra project), BUT: upon being asked by Harvard astrophysicist and space buff Jonathan McDowell, he denies any knowledge of this object and the letter and says he didn't make this identification. 

So who did make that identification then? Who wrote that letter, if truely there is a letter? Another engineer called George Luessis working for NASA?

Basically, at this point this whole story is falling to (green, glassy) pieces. The rock looks like material that is ubiquitous on Earth. There is nothing in the morphology to link it to a Space Program (let alone the Russian Space Program), i.e. nothing in the composition and morphology to think it is space debris. In fact, there is much in the morphology that makes that highly unlikely. And it is not clear who at NASA, if anyone at all, analysed the rock and "identified" it as "space debris". There is/was a George Luessis working at NASA, but it was not him. So who?

It can be seriously doubted that this green glassy rock is a piece of space debris. There is not a shred of verifiable evidence for it and much speaks against it.