Cosmos-2535, 2536, 2537 & 2538

Launch data:

Spacecraft data:

Description:

• The satellites were placed into an orbit very similar to that of Kosmos-2519/2521/2523

Mission details:

• On Jul 10, 2019 Russia launched a Soyuz-2-1v (light Soyuz with no strapon boosters, 5th launch) from Plesetsk. The Volga third stage placed 4 Russian Defense Ministry satellites in a 620 km sun-sync orbit and then maneuvered to a lower 475 x 510 km disposal orbit. At least one of the satellites is thought to be similar to the Cosmos-2519 (possible Nivelir-L) payload launched two years ago and used for rendezvous experiments.
• Cosmos-2535 and 2536 continue proximity operations. Cosmos-2537 and Cosmos-2538 (objects B and C but we′re not sure which is which) have not changed orbit, but in October several new objects were cataloged in a similar orbit and appear to have been released from objects B and/or C around Oct 11. They may be debris objects from a minor collision or sub-payloads for radar calibration (like the ESO test objects released from the Romb and Kol′tso satellites in the past).
• According to the Ministry of Defense, the satellites were intended for the studies of artificial and natural effects of space on the Russian spacecraft and the calibration of radar systems of the Air and Space Forces. Ground control had established and maintained telemetry communications with the spacecraft and their onboard systems had been functioning well.
• Space historian Jonathan McDowell reported that the NORAD tracking data had indicted that on August 1, 2019, at 02:00 UTC, Objects A (Kosmos-2535) and Object D (Kosmos-2536) had been within one kilometer from each other. On August 7, 2019, around 12:00 UTC, Kosmos-2535 and Kosmos-2536 satellites made their brief second encounter in orbit. In the meantime, all available tracking data showed that two other objects delivered into orbit in the same launch had not maneuvered.
• Then, between August 3 and September 30, 2019, Kosmos-2536 apparently disintegrated in orbit, forming 17 trackable debris.
  (Ref. www.n2yo.com: Satellite still in orbit)

External links:

• Satellite tracking (n2ya.com): Real time satellite tracking