The russian Kosmos 2519 satellite is satellite of unknown purpose launched on the third flight of the Soyuz-2-1v Volga launch vehicle. It deployed a subsatellite, Kosmos 2521, which in turn deployed one further subsatellite, Kosmos 2523. The missions satellites performed several maneuvers and proximity operation, which hints toward a prototye satellite inspector mission.
Reportedly it was built by Lavochkin and features technological experiments.
The mission consists of three satellites, apparently all different:
- Kosmos-2519, the main satellite. It performed orbital maneuvers. Suspected to be of the 14F150 type.
- Kosmos-2521, a subsatellite deployed from Kosmos-2519, which performed extensive orbital maneuvers.
- Kosmos-2523, a subsatellite deployed from Kosmos-2521. It performed no orbital maneuvers after deployment.
The three satellites of this mission performed a set of complex orbital maneuvers involving rendezvous, proximity operations and station keeping:
- On 27 July 2017 and 1 August 2017 Kosmos-2519 performed small orbital maneuvers to lower its orbit
- On 23 August 2017, Kosmos-2519 deployed the Kosmos-2521 subsatellite, which was called a "Sputnik Inspektor" in Russian media
- Kosmos-2521 drifted away, but maneuvered to make a 10 km fly-by with Kosmos-2519 on 11 October 2017, and then maneuvered away.
- Kosmos-2521 performed another set of maneuvers for another 10 km rendezvous on 15 October 2017 and a 2 km rendezvous on 18 October 2017. After this, it maneuvered again away to a distance of 15 km.
- On 30 October 2017 Kosmos-2521 deployed another subsatellite, Kosmos-2523, which in contrast to Kosmos-2521 did not perform any maneuvers after deployment in a slightly lower orbit than it's parent.
- Kosmos-2519 maneuvered on 14 December 2017 to perform a close 7 km fly-by on Kosmos-2521 the next day and again on 3 February 2018 in 10 km distance.
- After a maneuver on 14 February 2018 , Kosmos-2521 passed by Kosmos-2519 in about 30 km distance on 20 February 2018.
- Further manauevers Kosmos-2521 led to a 1 km fly-by on Kosmos-2519 on 1 March 2018
- After moving away to about 80 km, Kosmos-2521 conducted another 1 km on fly-by on Kosmos-2519 on 7 March 2018.
- Kosmos-2521 then moved away to about 550 km, to perform a 24 km fly-by on Kosmos-2519 on 26 March 2018.
- From 26 March to 30 April, Kosmos-2519 was stationkeeping within 1 km of Kosmos-2519.
- Kosmos-2521 lowered hits orbit on 30 April 2018 from 664 km × 660 km to 350 km × 369 km.
- From 27 June to 19 July 2018 Kosmos 2519 performed a series of maneuvers to change its orbit from 644 km × 659 km to 312 km × 606 km and then up to 317 km × 664 km. After this, no more orbital activity was observed.
- On 20 July 2018, Kosmos-2521 lowered its orbit to 292 km × 348 km. After this, no more orbital activity was observed.
Possibly the Kosmos 2542, 2543 mission is similar.