Soyuz-2-1v launches a military payload

On March 29, 2018, the Russian Ministry of Defense successfully launched a light-weight Soyuz-2-1v rocket carrying the EMKA satellite, apparently designed to test a new miniature Earth-imaging system.

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A notional illustration of the EMKA satellite.

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The EMKA mission at a glance:

Spacecraft designations EMKA, Zvezda No. 1, Kosmos-2525
Spacecraft mass ~150 kilograms
Orbit 319 by 347 kilometers, inclination 96.64 degrees; period: 90.94 minutes

Optical reconnaissance

Launch date and time March 29, 2018, 20:38:43.101 Moscow Time
Launch vehicle

Soyuz-2-1v (14A15 No. 005)

Launch Site Plesetsk, Launch complex 17P32-S4, Site 43, Pad 4

What is the payload?

The Russian Ministry of Defense did not provide details on the payload carried during the fourth launch of the Soyuz-2-1v rocket but a careful review of open sources made by Bart Hendrickx, a historian of the Russian space flight, had established a strong link between the mission and the Experimental Small Spacecraft program, EMKA, developed at the Moscow-based VNIIEM corporation. In 2016, the organization disclosed in its annual report that it had been working on a remote-sensing complex based on the EMKA spacecraft, which stands for "Eksperementalny Maly Kosmichesky Apparat."

The document also said that the satellite had been scheduled for launch in 2017 and the company had been gearing up to participating in its testing and flight control.

The public Russian data base tracking federal procurements also mentioned a contract between the VNIIEM corporation and the Ministry of Defense for the development of a satellite signed on Oct. 23, 2015.

A separate contract covered the delivery of the container with the EMKA spacecraft from Moscow to Plesetsk, which apparently took place on Feb. 24, 2018, aboard an Il-76 transport plane departing from the Chkalovsky airfield.

Finally, several other procurement documents from the Russian government listed the purchase of various services from VNIIEM and are associated with the EMKA project.

The EMKA mission

In a 2014 publication, co-authored by leading officials at VNIIEM and an officer at the Peter the Great Academy of the Strategic Missile Forces, it was disclosed that the company had began work on the MKA-V small satellite intended for taking high-resolution images of the Earth's surface. Defense applications were listed among various goals of the its mission.

The company apparently saw the development of the 205-kilogram MKA-V platform as a new step toward miniaturizing imaging satellites below the 450-kilogram Kanopus-V spacecraft series that VNIIEM had introduced previously.

The company emphasized that the MKA-V platform had been conceived as a basis for a multi-satellite and multi-task constellation, which would enable uninterrupted coverage of the Earth's surface with a wide range of sensors spread among highly specialized small satellites and linked into a single network by a space-based control spacecraft. The constellation would perform optical and radar observations as well as radio reconnaissance, clearly pointing at military applications.

The paper declared that in order to demonstrate key planned capabilities of the proposed MKA-V spacecraft, VNIIEM had decided to use its internal resources to launch the Zvezda (star) micro-satellite in the fourth quarter of 2015. (836)

A comparative table published by VNIIEM showed the capabilities of the MKA-V satellite and its Zvezda precursor as compared to Kanopus-V and SkySat satellites:

Orbital altitude
510 kilometers
300 kilometers
450 kilometers
450 kilometers
90 by 140 by 175 centimeters
90 by 70 by 140 centimeters
90 by 100 by 160 centimeters
60 by 60 by 95 centimeters
450 kilograms
150 kilograms
250 kilograms
120 kilograms
Imaging resolution
2.1/10.5 meters
0.5-0.9/2.2-3.6 meters
0.6-0.8/2.2-3.6 meters
0.9 meters
23 kilometers
7.2 kilometers
17 kilometers
8 kilometers
Spectral range
0.52-0.85 micrometers
0.52-0.85 micrometers
0.52-0.85 micrometers
Image format
Panchromatic and RGB
Panchromatic and RGB
Panchromatic and RGB
Number of digitizing modes
Operational life span
5 years
1 year
5 years
1-2 years

In a 2015 presentation at the Korolev readings in Moscow, specialists from VNIIEM said that they had chosen K50-10.5 hydrazine thrusters developed at OKB Fakel to provide attitude control for the Zvezda spacecraft. (837)

VNIIEM further detailed the experimental remote sensing satellite in 2015. It listed the following imaging modes for the spacecraft:

  • Imaging along the satellite's ground track;
  • Imaging under angle away from the ground track;
  • Wide-band imaging;
  • Object imaging;
  • Object imaging in a "reverse" mode;
  • Video-imaging;
  • Stereo-imaging.

The document also said that the spacecraft used an unpressurized platform and its mass was under 200 kilograms. It relied on a three-axis attitude control system employing electric fly wheels. (838)

Also, SKTB Plastik, based in the town of Syzran, announced that it had developed and manufactured the carbon composite structure of the optical module for the Zvezda satellite. According to the company, the module had dimensions of 1,276 by 405 by 721 millimeters and had a mass not exceeding 30 kilograms. The body carried star trackers, batteries, thermal insulation, an interface for the attachment to the rest of the spacecraft, temperature sensors and titanium heating elements.

Soyuz-2-1v flies its fourth mission


It is known that the fourth launch of the Soyuz-2-1v rocket with the EMKA payload was previously targeted for October and November 2017 but by the first week of December of that year, the mission had to be postponed to the beginning of 2018. At the beginning of January, the launch was expected on February 28, but by the middle of February, the mission was postponed again to a period between March 23 and 29, 2018. The State Commission overseeing the preparation for launch met on March 26 gave go ahead to the rollout to the launch pad, which took place next morning on March 27.

The liftoff of the fourth Soyuz-2-1v rocket was finally set for March 29, 2018, at 20:38:43 Moscow Time (1:38 p.m. EDT, 17:38 GMT), from Pad 4 at Site 43 in Plesetsk, and according to the Russian Ministry of Defense, the launch had proceeded as scheduled.

The rocket likely headed almost exactly north, under the combined propulsion of a single NK-33 main engine and the four thrusters of the RD-0110 steering engine. Lacking the four strap-on boosters of its predecessors in the Soyuz family of rockets, Soyuz-2-1v relied solely on a modified core booster as its first stage.

Following the first-stage ascent, the second stage took over the powered flight around two minutes into the flight. It fired its four-chamber engine moments before the separation of the first stage, thanks to a lattice structure connecting the two boosters, which allowed the free flow of the exhaust from the nozzles above. Right after the separation of the first stage, the tail section of the second stage split into three segments and fall away.

Both, the first stage and the fragments of the tail section were to splash down in the Barents Sea, north of Murmansk.

As the second stage continued its burn, the payload fairing protecting the satellite split in two halves and also separated. Its fragments were to fall into the Arctic Ocean, south of the Spitsbergen Archipelago.

EMKA maneuvers in orbit

The spacecraft separation was scheduled at 20:46:33 Moscow Time. The newly launched satellite was expected to contact ground stations around 22:10 Moscow Time (3:10 p.m. EDT) during its second orbit. After the launch, the satellite received the official designation Kosmos-2525.

Although, in first several months of its mission, the satellite's orbit had decayed from around 320 kilometers to as low as 270 kilometers, in October 2018, Kosmos-2525 began periodic orbit-raising maneuvers that kept its altitude at around 280 kilometers, as Western radar data reviewed by a space historian Jonathan McDowell indicated.

After three years in orbit, Kosmos-2525 reentered the Earth's atmosphere over the South Pacific in the early hours of April 1, 2021, western radar data showed.

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Page author: Anatoly Zak; Last update: September 10, 2021

Page editor: Alain Chabot; Last edit: March 29, 2018

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A possible depiction of the Zvezda (EMKA) satellite. Credit: VNIIEM




A body of the optical module developed for the Zvezda (EMKA) satellite. Credit: SKTB Plastik


A Soyuz-2-1v rocket with EMKA satellite is being prepared for rollout to the launch pad. Click to enlarge. Credit: Russian Ministry of Defense


A Soyuz-2-1v rocket rolls out to the launch pad in Plesetsk on the morning of March 27, 2018. Click to enlarge. Credit: Russian Ministry of Defense


A Soyuz-2-1v rocket lifts off with the EMKA satellite on March 29, 2018. Click to enlarge. Credit: Russian Ministry of Defense