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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.

After launch, only one payload appeared, Kosmos 2542. Likely it is of the 14F150 type like Kosmos 2519. This one is suspected to be a satellite inspector payload, as it synchronized its orbit with that of the US reconnaisance satellite KH-11 16 (Crystal 16, USA 245) and is following maneuveres of the US satellite.

After some time in orbit, a smaller subsatellite, Kosmos 2543, was deployed. It appears to be related to earlier inspector satellites ("Sputnik Inspektor") like Kosmos 2521. Both satellites share the same 368 km × 858 km × 97.9° orbits and remain within about 10 km of each other. When KH-11 16 raised its orbit, both Kosmos satellites accordingly followed soon after, providing close passes of a few dozen kilometers distance. Later in May 2020, Kosmos 2543 adjusted its orbit to fly in formation with Kosmos 2535.

In July 2020, an object seperated from Kosmos 2543. This might be similar to Kosmos 2521. According to US officials, this object displayed characteristics of a space-based anti-satellite weapon.

These satellites were launched on 25 November 2019 on a Soyuz-2-1v Volga rocket from Plesetsk.