Wednesday 20 May 2015

Tracking MiTEx 1

MiTEx 1, 18 May 2015 (click to enlarge)

Over the years, the USA has been experimenting with satellites intended for close-range inspection of other satellites at geostationary altitudes.

The first one was the highly secret Prowler (1990-097E), clandestinely launched on Space Shuttle mission STS-38 in 1990. Two other ones were launched less covertly, though their orbits were and are classified: the experimental MiTEx satellites, MiTEx 1 and MiTEx 2 (2006-024A and B), brainchilds of DARPA, launched from Cape Canaveral in June 2006.

Speculation on the reason for their development can be found here. What we do know is that early 2009, two-and-a-half years after their launch, both MiTEx satellites were used to inspect the malfunctioned DSP-23 satellite. This was actually observed by amateur trackers Greg Roberts and Peter Wakelin.

MiTEx is an acronym that stands for Micro-satellite Technology Experiment.They are small objects, each weighing about 225 kg. While some sources (similar statements also here) have tauted that "ground-based detection via visual observation or radar is extremely difficult if not impossible" for these small objects at such a large distance, matter of fact is that amateurs (including me) actually track these objects, albeit infrequently.

The image in the top of this post shows MiTEx 1 (2006-024A) imaged on May 18, 2015, using the 0.51-m telescope of Warrumbungle Obs. in Australia. The satellite was at a low sky elevation.

I also imaged it two days earlier, on May 16, and captured it briefly flaring at that time (the trail is leaving the FOV of the CCD camera at left in this image):

MiTEx 1 is currently located in a disposal orbit at an orbital altitude just above that of operational geostationary satellites. It is drifting Westwards at a rate of about 5-6 degrees per day. During my May 16 and May 18 observations, it was moving westwards over the mid-Pacific south of Hawaii, as shown on the map below. The map also shows the drift path over the next two weeks, until the satellite's approximate position for June 1. The "wobble" in the path is the daily analema it makes due to the slight inclination of its orbit. Footprint shown is for May 18.

(click map to enlarge)

Where the MiTEx 1 sistership  MiTEx 2 (2006-024B) currently is, is less certain: my attempts to recover it near its expected position on May 16 and May 18 based on a 20-day old elset failed so far.

Thursday 14 May 2015

[UPDATED] Why the Emergency Asteroid Defense Project (EADP) will not fly, imho

[editted and expanded May 15, 2015, to reflect on the content of the legal report commissioned by EADP. Edits and expansions are in italics between square parenthesis, to differentiate them from the original first version published]

The danger of an Asteroid impact is a real threat. To that, everybody agrees. It is however also (and I am not alone in stating this) a threat that has been, and is, overhyped by some.

Lately, a number of publicly very vocal groups have jumped on the bandwagon of  'asteroid defense'. Within the community of asteroid researchers (of which I am very modestly a member -  I search for and have actually discovered Near Earth Asteroids), some of these groups raise eyebrows and generate a somewhat uneasy feeling. Several people in our small community feel that some of these groups, often consisting of people considered outsiders, hijack the issue and overhype a threat in a way that is detrimental to the real issues and complexities involved.

One of the newest initiatives in this game is the Emergency Asteroid Defense Project (EADP). EADP wants to rescue us from a potential asteroid on a collision course with Earth. Note: there isn't such an asteroid in the picture yet.

On their website, EADP presents itself as a Denmark-based NGO that wants to develop and build an asteroid defense system for this purpose. The defense system EADP wants to build consists of two parts:

(1) a kinetic impactor, that will create an impact crater on the target asteroid;

(2) a small nuclear bomb that will next be steered into this crater and detonated, shattering the asteroid into smaller pieces.

Sounds feasible right?

EADP has just created a lot of publicity by starting a crowd funding initiative on Indie-gogo to jump-start their plans. They aim to raise money for a feasibility study and then launch their first test mission as early as 2017.

Mind you: to succinctly make clear what they propose, they propose to launch a nuclear bomb and detonate it on another celestial body. Or at least: develop the technology for it.

Now, IANASL (I Am Not A Space Lawyer). But apart from the worry that it is a private enterprise rather than a (consortium of) Nation States or the UN undertaking this: in my humble opinion, this plan runs foul of at least two international treaties, in a way that will not be easy to resolve and should not be glossed over.

EADP so far appears to do however . You should realize this before you toss your money to EADP.

[note added 15 May 2015: there is actual a legal report on their website - not their Indiegogo page - which is a bit buried, addressing these issues. From the contents of this report and its major recommendations - especially the first one -, it is clear that the issues raised should not be neglected. This is important for a crowd funding campaign, as this is information about the feasibility of the project and attached problems that potential backers need to know in order to decide whether to back the initiative. This report should have been a primary part of their Indiegogo appeal page]

For the plans of EADP to become reality, they need to:

(1) have c.q. develop a nuclear explosion device (i.e. a nuclear weapon);

(2) develop a kinetic impact weapon;

(3) find someone willing to launch these.

With regard to point (3), on their website EADP mentions the US commercial launch corporation SpaceX as an option. I have my doubts about their time-plan however: 2017 seems very soon to commission a launch. Building and launching rockets takes time [let alone tackling the political and licensing issues]. There are moreover other problems to employing SpaceX, discussed below.

Kinetic impact missions are not new. The technology for this already exists. Witness for example NASA's Deep Impact mission and LCROSS mission.

The problematic aspect is the nuclear payload that is employed next. And again, the technology is not what is most problematic here. The real problems are geopolitical.

EADP is Denmark-based, and they are an NGO (Non-Governmental Organization, i.e. a private enterprise of citizens). Denmark as a country itself has no nuclear weapon capability - and it is very doubtful that a sane government would put that capability at the hands of an NGO anyway, would they have it. Denmark also currently doesn't have their own space launch capability (but they do take part in ESA, which has). So they would be dependent on foreign countries for a launch capability (e.g. the US SpaceX, or ESA as a European organization, or Roskosmos in Russia, JAXA in Japan or perhaps the Chinese), and EADP would either have to develop/build the nuclear device themselves (but: see below), or obtain it from a country that does have a nuclear capability.

Here, they face their first problem: the Treaty on the Non-Proliferation of Nuclear Weapons (NPT). The nuclear powers US, UK, France, Russia and China all signed this treaty. They would violate this treaty would they help EADP to a nuclear explosive device. They would also violate it by simply providing the technological aid for it (i.e. helping to develop it).

Likewise, given that Denmark - although not possessing a nuclear capability on its own -  is a signatory to the treaty as well, the Danish government can not allow EADP to develop a nuclear explosive device themselves, as that again would breach the treaty they signed. 

[note added 15 May 2015: while the legal report commissioned by EADP discusses the Partial Nuclear Test Ban Treaty (NTB), not a word is being said about the NPT).

Israel, Pakistan, India and North Korea also possess The Bomb and did not sign the treaty. Yet, it is highly doubtful they will openly share their technology with EADP. And if they would, they would get in severe trouble with the other nuclear powers. Handing your nuclear technology to private organizations in another country is the kind of thing that starts a war, as it might lead to nuclear technology falling into the wrong hands. The USA has invaded and bombed countries for less.

Moreover, EADP would still get in trouble with the fact that Denmark, the country in which they are based, has signed the treaty. Note that EADP need not actually build the actual device, for this to be problematic.

So there you have one problem with the plans of EADP.

But as if that is not enough, there is a second problem: the Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies of the United Nations (also known as the 'Outer Space Treaty').

This treaty has been signed by many countries, including Denmark and the United States. It regulates what can and can't be done in Outer Space and on celestial bodies other than Earth.You can find the full text of this treaty here. Important to realize, given that Denmark signed the treaty and EADP is a Danish-based NGO, is that the treaty unequivocally states that:

"States bear international responsibility for national activities in outer space, whether carried on by governmental agencies or by non-governmental entities"

In other words: EADP, as a Denmark-based NGO, cannot do as they wish: they are bound by the treaty signed by the Danish government. Even if EADP would outsource the nuclear device and/or the launch to another country, Denmark (plus the other countries involved in the launch) is responsible. Basically, this means that under the Outer Space Treaty, they can't allow it (just like they can't allow it under the Nuclear Non-Proliferation Treaty).

Of relevance are also provisions 2 and 3 of article III of the Agreement Governing the Activities of States on the Moon and Other Celestial Bodies that is part of the Outer Space Treaty. These state that (and note that while the texts below talks about the Moon, the preamble to these clauses makes clear it concerns not only the Moon but all other celestial bodies other than Earth, i.e. including asteroids):

States Parties shall not place in orbit around or other trajectory to or around the Moon objects carrying nuclear weapons or any other kinds of weapons of mass destruction or place or use such weapons on or in the Moon.
The establishment of military bases, installations and fortifications, the testing of any type of weapons and the conduct of military manoeuvres on the Moon shall be forbidden

In other words: launching, let alone detonating, a nuclear explosive device to and on another celestial body (like an asteroid) is simply forbidden. In fact, I think Space Lawyers could get into a real heated argument whether testing with a dummy payload already breaches this clause of the Outer Space Treaty, as a test with a dummy load is still a test, i.e. it relates to the 'testing of any type of weapon' in the clause above. [Von der Dunk, legal advisor to EADP, thinks it is not].

These are questions that, in an international diplomatic environment, therefore should not be taken lightly (and on which different countries and different lawyers might take different viewpoints).

[Von der Dunk basically says the same in his report: at various points in the report it is stressed that "in view of the geopolitical sensitivities" the EADP initiative requires a firm open discussion on these points from a  very early stage onwards. i.e.: that these geopolitical sensitivities should not be underestimated (which is exactly the main point which I argue here!). This is also the first of the main conclusions at the end of the report (p. 32): "It would be recommended for the EADP to:  * Address from an early stage onwards and in a continuing fashion the risk of ‘political fall-out’ outside the United States which EADP missions might give rise to"]

Point is: while it would be possible that countries united in the United Nations would, in the context of the United Nations Assembly, perhaps lift these provisions in the case of a real, imminent asteroid impact danger (but: don't put up your hopes high, folks!), there is imho no way a private enterprise like EADP would get this off without such a real, imminent danger. [again, Von der Dunk appears to actually  agree on this in his report: lifting of certain treaties is seen as feasible by him in case of an "emergency situation", i.e. a real imminent threath]. It is highly, highly unlikely that they would get any country to cooperate with a test mission for this purpose (which is what they are fundraising for) as, even with a dummy load, this basically still is a weapons test in Space (or at least could be seen as this by third parties) and hence diplomatically a very sensitive issue.

Now, if you pose this case to space lawyers, they will tell you that the wording of the Outer Space Treaty is ambiguous. There is also the question, whether a nuclear explosive device to blow up an asteroid should be regarded as a weapon. There is discussion possible about that [e.g. Von der Dunk thinks it isn't necessarily so. ]. But that is not the point. Or rather: it is.

Countries tend to be suspicious of each other's intentions when doing outlandish things like this. Some countries might see it as a covert military space weapons test. Remember, for example, how the shootdown of the USA 193 satellite (an imminent [artificial] impact threath from earth orbit according to the US government) was and is widely regarded and criticized as a covert ASAT test by other countries. The USA itself has expressed significant worries about recent Chinese activities in both near and deep space (including experiments the Chinese themselves present as being purely "scientific") which it considers as covert Space Weapon tests. The same is true for US and other countries' concerns about the true intentions behind the North Korean and Iranian space programs.

This gives you an idea about how sensitive this all is. Strapping a nuclear load (even if it is a dummy) onto a rocket capable of reaching and leaving Earth orbit, basically makes it an ICBM test. EADP is therefore seeking to develop technology that by all means could be considered ICBM technology by some countries. It is clear, that international arms treaties and the NPT get relevant here. Thinking they do not, is irrealistic.

EADP mentions SpaceX. Note that SpaceX, as a US company, is bound by the treaties the USA signed. They cannot launch a nuclear device (or even a dummy test load of such a device) for EADP without the US Government's approval, and the US Government in principle cannot do this without approval of the international community (represented by the United Nations) as they would otherwise breach the Outer Space Treaty. I also doubt that the US government would be okay with a private US company launching a technology test that ultimately includes a nuclear explosive device developed by a private entity in another country. This is stuff where ITAR (the International Traffic in Arms Regulations) is potentially relevant, and the US Government has been a pain in the neck with respect to ITAR issues even to organizations like NASA.

These are things that, in the face of international geopolitic realities, should not be glossed over lightly. You should not think you can just happily build and test technology for a kinetic and nuclear impact device, expect another country to launch it for you, and think other countries will be okay with that and believe Denmark is out to Save the World. It just doesn't work that way. Not even for Denmark, as much as I love that country myself.

Note that the point also isn't whether you actually build and design the nuclear device. EADP is now (on twitter, after critical questions) stressing that they don't want to test the nuclear device but leave that to "specialists"They emphasize that they "must stress that handling nukes is not our job but the government's" (they don't say which government, by the way). They also said that "we will not be the decision makers but merely the providers and the fundraisers for the technology".

But, besides that it is odd to simply waive away testing the most crucial part of the proposed mission and technology, it is besides the point that they say they only develop, not actually build a nuclear device. Developing the technology meant to bring a nuclear explosive device into space, already is something that is (or should be) reason for concern.

This brings us to the real issue at hand. This issue is not whether some treaties are outdated and are at odds with reality and a hindrance to legitimate activities in space (they are). This is not about whether we should or should not try to do something in case we detect an asteroid on a collision course, either.

The real issue is that EADP is fundraising for a project, without having done the necessary diplomatic groundwork.

And that is where the real issue is. This is not an issue of technology. It is not an issue of money. It is a diplomatic issue, and the EADP initiative currently does not solve this. Even though it is the first thing they have to overcome for their plans to become reality.

[added 15 May 2015: Indeed, this also seems to be the explicit view of Von der Dunk in his legal report for EADP. The very first point of his final recommendations (p 32) reads:

"Address from an early stage onwards and in a continuing fashion the risk of ‘political fall-out’ outside the United States which EADP missions might give riseto, in particular as regards the use of NEDs in actual threat mitigation missions, byway of information of and appropriate consultation with the other states of the world, the United Nations and the global scientific community and by stressing the clear benefits for and interests of all mankind and all states in the EADP mission"
He also clearly warns (top of page 32) that not everybody might share his assessment that the EADP plans are not necessarily running counter to treaties like the NTB and OST:

"This is not to say, however, that in the present geo-political reality such a legal analysis would be globally shared, and efforts should be undertaken at the international level to minimise the potential for any ‘political fall-out’ that might result from the intended use of NEDs in outer space in such emergency scenarios, preferably by way of open and transparent information of, and as necessary consultation with, the other states of the world, the United Nations and the global scientific community"

i.e., on these points, the EADP commissioned Von der Dunk report actually confirms what I argue here: that geopolitically, this is a very sensitive issue. He also specifically mentions that circumnavigating these sensitivities takes a lot of time and diplomatic effort. I observe that this in turn is something which is nowhere reflected in the time-line put forward by EADP in their Indie-gogo appeal]

Their crowd-funding initiative hence seems extremely premature, and their timeplan is overtly ambitious given the realities of the diplomatic (apart from the technological and logistic) trouble they'll have to face.

What worries me, is that in their crowd-funding pitch to the public, they nowhere mention these fundamental issues. There for example isn't any statement that the Danish government is positively supporting all this (I have put out this question to EADP by twitter but received no answer yet). Nor on how they see their plans in the context of the various international treaties. [a legal report is included on their company webpage, but nothing of this is raised in their Indie-gogo appeal]

One of the EADP partners, Remco Timmermans, in answer to my question, simply claims on twitter that "This is a private enterprise. No government approval needed to do a technical design study".

Again, IANAL, but I highly doubt this is true. Private enterprises are not exempt of complying to the international treaties which their Governments sign, and the ramifications of such treaties are usually signed into the law of the signing country.

[Von der Dunk in his report does not discuss how this pertains to a technical design study, but makes very clear that government oversight indeed pertains to an actual space mission: "First, states are going to be held internationally responsible for any potential violation of international law resulting from space activities also if conducted by private entities. Further to such international responsibility, the ‘appropriate state’ would then be actually required to ensure “authorisation and continuing supervision" of such activities"].

So yes: government approval will be needed, given that Denmark signed treaties that (a) stipulate that Denmark does not acquire nuclear weapons technology on its own, nor acquires it from other countries; and (b) stipulate not to test weapons in space.

As pointed out,  the Outer Space Treaty explicitly states that Governments are responsible for what non-governmental organisations based in their country do in Space. I also doubt the Nuclear Non Proliferation Treaty would allow loopholes of the kind expressed by Timmermans. Just have your nuclear weapons developed by a private enterprise rather than the State and all is okay? That Kim never thought of this!

So I would expect the Danish government to take a keen interest in this. Here is a group of private citizens developing technology for a nuclear space mission, and indicating they will hand this technology to a third, foreign party for the operational part. That should raise alarm bells.

In another twitter answer to me EADP does say that the "legal raport [sic] and groundwork has been done" but here is the point:

To their audience of potential crowdfunders they do not say a thing about all these international legal and diplomatic issues involved.

And with whatever they may say on Twitter, I see no indication that these issues have been solved yet [added May 15, 2015: also not after reading Von der Dunk's commissioned report, which makes very clear that these geopolitical sensitivities should not be underestimated and demand action and openness from a very early stage onwards].

Again: IANASL (and I would like to see some independent Space Lawyers chime in here!). But you don't have to be a Space Lawyer to see the trouble ahead.

The whole crazy idea has elements in common with the much discussed Mars One project: a bold, even downright crazy plan that however speaks to the imagination (the project had immediate staunch supporters), and which National governments so far didn't dare to tackle yet. Ad to this a lot of publicity, an easy glossing over very real political problems involved, and presenting an unlikely timetable. And of course, having it all in the end primarily revolve around solliciting money from the public.

If EADP doesn't want to become the next Mars One and wants to be taken serious, they will have to explicitly and honestly address these issues first: their plans in the context of national and international agreements, laws, and geopolitical reality.

And yes, it sucks that the survival of humanity is held in suspension by such geopolitical realities. But what is new under the sun here? Look at how we (not) handle global warming.

[final notes added May 15, 2015: 

- EADP on twitter berates me for focussing on the nuclear part of the project. That is their good right of course: but I find it disingenious how they try to separate the issues around a nuclear explosive device (NED) from the rest of their project, given that a NED is an integral part of the eventual deflection technology they want to develop and test. In my opinion, you can't seperate the issue of launching a NED from the current discussion.

- I want to stress again that my main point is the apparent easy way with which EADP, in their Indie-gogo appeal towards potential financial backers, glosses over the geopolitical realities pertinent to their plan. It is my firm position that this is not correct: in order to make a fair judgement on whether this plan is backable, potential donors need to be honestly provided with information on the potential difficulties to be encountered as part of the endeavour.]

(I thank Brian Weeden for some comments on a draft of this post. All opinions expressed are however solely mine)


On 16 September 2014, the US military launched an enigmatic satellite (2014-055A) from Cape Canaveral into a geostationary orbit. It was not disclosed for which agency the object was launched (this is information that usually is disclosed). Nor what its function would be (this is information sometimes but not always disclosed). All we know is the rather uninformative name, CLIO, that it was built by Lockheed Martin and based on their commercial A-2100 bus.

CLIO imaged on May 13, 2015 (click image to enlarge)

CLIO is currently located at longitude 108.0 E, over Indonesia, where I imaged it yesterday using the 0.51-m telescope of Warrumbungle (MPC Q65) in Australia. The image can be seen above: CLIO is positioned just north of Telkom 1 (1999 042A), an Indonesian satellite for satellite telephony. (since Telkom 1 is also built on a Lockheed A2100 bus, the brightness difference in the image above is interesting, and probably due to different attitudes (orientations) of the satellites, although it potentially could also indicate custom components on CLIO, e.g. something like a large dish antenna).

click to enlarge

In many ways CLIO appears similar to another enigmatic satellite,  PAN (USA 207, 2009-047A), launched in September 2009 and infamous among our amateur tracking network for its frequent repositioning.

PAN was also built by Lockheed Martin and like CLIO based on the A-2100 bus. As with CLIO, the government agency behind it was not disclosed, and no indications of its role provided. What was known, is that PAN was developed and built rapidly (in less than 3 years time) using off-the-shelf commercial parts, apparently in response to an urgent need of some undisclosed government agency (which I suspect is either the CIA or NSA). Much speculation has occurred about the role of the spacecraft. The frequent relocations (which stopped at the end of 2013) make clear it is not a simple communications or early warning platform. PAN is currently located at longitude 47.9 E over east Africa.

Because of the similarities, several analysts believe that CLIO, five years after PAN, is a follow-on to the PAN program. The two satellites are currently 60 degrees separated in longitude.

Monday 11 May 2015

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.

Friday 8 May 2015

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....

Yet another ISS transit over the Sun

Today, only a week after the transit of May 1st, I had another transit over the Sun of the International Space Station ISS here at Leiden. It happened on May 8, 2015 at 10:48:25 UT (12:48:25 local time).

The animated GIF above was made from four images and shows the ISS and clouds moving in front of the sun. In reality, the transit happens much faster than the GIF suggests by the way:it took less than 0.6 seconds in real time.

At first it looked like I would completely miss the transit: an hour before the transit it was still completely clouded.

About 20 minutes before the transit the cloud cover however started to break, and the Sun started to glimpse through. I quickly set up the Celestron C6  (a 15-cm Schmidt-Cassegrain) and while clouds were still partly obliterating the solar disc, I managed to snap a series of four images showing the ISS silhoueted against the solar disc. Unlike a week ago, this time a nice group of sunspots was visible as well.

Below are a still image and a detail from that still, showing the ISS with well recognizable solar panels just south of the sunspot group (note that the time in these images is 10 seconds off, it should be 10:48:25 UT).

click images to enlarge

Progress M-27M is down!

click map to enlarge

According to US military tracking data from JSpOC, the out of control Progress M-27M cargoship that should have brought supplies to the ISS, re-entered over the southeast Pacific near 51 S, 87 W, moving towards Tierra del Fuego, on May 8 at 02:20 UT, +- 1 minute.

The map above shows its approximate re-entry position. Remember: re-entry in reality is a process that takes several minutes, during which it moves along the shown track (shown track is the last orbital revolution plus a small part of the track in front of the nominal re-entry position).

Several analysts believe that re-entry times given to a plusminus of only 1 minute by JSpOC are based on Space-based detections by the US military's SDP DSP and SBIRS infra-red early warning satellites. These detect and geolocate the infra-red signature of the fireball caused by the re-entry.

In this particular case, this is the more likely because the last three published orbital element sets from (we assume) regular tracking facilities are clearly not too accurate. So the very short uncertainty interval in the re-entry time given, must be based on some other unpublished data source.

The clear problems with the last few element sets issued is one reason why I did not make any further forecasts after the one I issued at 18:30 UT yesterday, 8 hours before the actual re-entry.

My prediction at that time (2:03 UT +- 2 hrs, which I rounded to 2:00 UT +- 2 hrs given the uncertainty interval) actually is not that far off from JSpOC's final re-entry time.

Meanwhile, official Russian ROSKOSMOS sources give a re-entry time that is 15 minutes earlier (and very similar to my prediction hours before) than that suggested by US military tracking sources. The Russians state re-entry at 2:04 UT (5:04 Moscow time) over the central Pacific south of Hawaii (red dot on the map above). This is likely to be a 'forecast' (or 'aftercast' rather) based on tracking data and/or telemetry obtained during the hours before. No uncertainty interval is given.

Thursday 7 May 2015

[UPDATED] Progress M-27M re-entry predictions

[predictionlast updated 7 May 18:30 UT]
[update 8 may 2015: NEW post  about the re-entry HERE]

I am providing occasional estimates for the uncontrolled re-entry of Progress M-27M on my Twitter feed today. Likewise, several other people are providing estimates, of which I would want to recommend those by Ted Molczan on the Seesat mailing list. You will note that the re-entry predictions will vary from source to source!

My current estimate is for re-entry to occur:

between 17 and 22 UT on May 7
between 21:10 and 01:30 UT  May 7-8

between 00:00 and 04:00 UT May 8

(estimate update issued 7 May, 18:30 UT based on elsets up to epoch 15127.69084936 processed with Alan Pickup's SatAna and SatEvo software).

Within this window, the slightly more likely moments are around and just after perigee passage, i.e. the tracks over the Pacific in this case.

The estimate may still change as new orbits are released. Previous released elsets initially strongly pushed the estimated re-entry time back from early May 8 to late May 7, as the result of solar activity yesterday and the resulting effects on the outer Earth atmosphere. As a result, my earlier estimate of this morning (May 7) overestimated the decay rate. With the new orbital update from epoch 15127.50860911 and onwards things are settling towards more realistic values, with a trend of slightly moving the decay window to a later time.

Above is a rough map of where the re-entry might occur, based on current uncertainties.

For updates, keep an eye on my Twitter feed.

[update: final re-entry results have been posted in a new post here]

Saturday 2 May 2015

Another ISS solar transit

On May 1st 2015 near 13:53:18 UT, there was another solar transit of the International Space Station ISS as seen from Leiden.

The weather was clear (apart from some thin cirrus) and I imaged the transit in the prime focus (F/10) of my Celestron C6, using the Canon EOS 60D at rapid burst (5.6 photographs per second). The telescope was equiped with a Baader foil solar filter and images were taken at 1/4000th second exposure (to avoid motion blur) and ISO 800.

The transit took place near the upper northern limb of the sun and was hence short. Only three images show it.

The image above is a stack of all three, superimposed on the first image. The image below is an animated GIF of all three images. In reality, the transit was much faster (about 0.4 seconds in total) than the GIF shows.