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Launches and Orbital Operations

Tyneside, UK
2024 May 20
Monday, Day 141

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Shenzhou 12 Debris


New Items Catalogued

2021 Sep 24, Space-Track issued orbit data for five new objects in orbits slightly lower than Shenzhou 12's final one. The orbits are decaying more quickly than Shenzhou 12's Orbital Module that is still in space.


Shenzhou 12 fired its retro-rocket and landed September 17 after letting go of its orbital module a minute or so earlier. It is possible that the debris was shed as the OM pulled away but this is not something that occurred with earlier flights of the standard-production Shenzhou spacecraft - ie Shenzhou 8 onwards.

Early orbit datasets from Space-Track point to the debris having separated from Shenzhou or the orbital module on September 17 or 18 but more data is needed in order to be more precise.

What is it?

Prior to Shenzhou 8, the orbital modules had their own solar arrays and remained in orbit for many months operating as independent satellites. Since then they have been used as cargo space and astronaut living space. The additional science/engineering payloads have been eliminated so any thought of them being instrument covers can probably be eliminated.

Cubesats, or similar small satellites is a possibility but nothing has appeared in official Chinese news items.

It may simply be debris, perhaps 'spun off' as a result of uncontrolled rotation of the OM. At the time the first orbit data was published the average orbit height was about 375 kilometres with perigees as low as 371 kilometres and apogees as high as 391 kilometres.


There is another, slightly interesting, possibility that results from comparing the the catalogues of objects for individual Shenzhou missions. They tended to have 4-5 objects tagged by Space-Track as 'CZ-2F Debris' that appeared at launch and were left in similar orbits to the rocket before Shenzhou commenced its own manouevres.

There were none for the Shenzhou 12 mission but these five new items appeared at the end of the mission.

It raises the question of whether this debris is the same complement of items released by earlier Shenzhou missions when the spacecraft were still accompanying their upper stage rockets - hence them matching the orbit of the launch vehicle.

Their delayed appearance could result from a fault or an error. Alternatively, there may have been a change in mission profile. They may be insulation or covers for something that is not required until the return to Earth, and they are now being retained until departure from orbit.

Page Date - 2021 Sep 25
Plot updated in real time

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