Saturday, 9 May 2020

The Kosmos 482 Descent Craft: imaging an old Soviet Venera probe stuck in Earth orbit

click to enlarge


On May 7 I imaged a pass of the Kosmos 482 Descent Craft (1972-023E), using the WATEC 902H camera and a SamYang 1.4/85 mm lens. This is a very interesting object on which I have blogged earlier.

It is the ascend module of a 1972 failed Soviet Venera probe, meant to land on Venus but stuck in Earth orbit after its apogee kick engine failed to push it into Heliocentric orbit towards Venus in 1972. This is the video from (a part of) the May 7 pass of this object:

The object on the video, at that time at an altitude of about 1640 km and range of 1845 km, is about 1 meter large and weighs 495 kg. It should look like this:

photo: NASA. Click to enlarge

The photo above is not Kosmos 482 itself, but an exhibit replica of a sister ship, the Venera 8 landing module in its protective shell. Venera 8 was launched four days before Kosmos 482, and unlike the latter it was successful and did reach Venus.

The failed Kosmos 482 probe still in Earth orbit was launched from Baikonur on 31 March 1972, and put in a highly elliptical 220 x 9200 km parking orbit around Earth. It's apogee kick engine next failed to push it into a heliocentric orbit towards Venus, and the spacecraft then broke up into four pieces.

Three of these four pieces have already reentered, the fourth, that is believed to be the landing module in its protective shell, is still on-orbit and is the object I imaged. It's apogee altitude has been lowering significantly since 1972.  The object will probably reenter somewhere around late 2025 or early 2026: I wrote an extensive blog post about it including a lifetime simulation a year ago.

The diagram below is from that post and shows the observed orbital decay up to March 2019, and the future decay (light blue) that I modelled with GMAT:

click diagram to enlarge

The interesting thing is that the Kosmos 482 Descent Craft might survive reentry largely intact! It is, after all, a lander that was meant to survive ascend through the thick atmosphere of Venus. It's parachute system will probably no longer function (so it will impact rather than land), but we can expect the hardware to reach Earth surface largely intact.

From a Space Heritage point of view, both this and its history makes this 48-year-old piece of Soviet Space hardware a highly interesting object. This is material culture that represents humanities' babysteps in the exploration of other planets.

Which makes this an interesting object to image, from a "Space Archaeology" viewpoint, and an interesting object to keep an eye on the coming years, until it reenters about six years from now.

Added Note9 May 2020 13:30 UT:

In response to my statement that the object likely is the lander in its enclosing protective shell, several people have pointed me to telescopic imagery that purportedly would show that a part of the main bus is still attached.

I (and many others in the amateur satellite community - we had a heated discussion on it on the Satobs list a few years ago) distrust imagery of this kind. This is imaging at the edge of resolution, in this case also notably from a non-stable imaging platform (handtracking a moving object at the limit of resolution!). It unfortunately includes cherrypicking frames. It is very difficult to objectively determine what is real detail and what is artefact of the imaging procedure. It is easy to overinterpret.

I also want to note that taking the mass and dimension of the lander only, actually give a very good fit to the observed orbital decay.


FL said...
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FL said...

You should try to do some imaging of Kosmos 482 during periapsis! I've done telescope imaging of the ISS and imaging of some other large satellites such as ENVISAT. For Kosmos 482, there is quite a strong suggestion of an elongated cylindrical shape.

You are right that there is a lot of picking-and-choosing when you are so close to the practical limits of your equipment, but there is enough to tell that the apparent size of Kosmos 482 is much, much larger than most satellites which typically appear as nothing more than a fuzzy point source.

I love your blog, keep up the great work!