Soyuz rocket launches European satellites

After a 24-hour delay by a technical problem, the Soyuz rocket family concluded its operations in 2019 on December 18 with a launch from the South American coast of French Guiana, successfully delivering five satellites for European customers.

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Soyuz VS23 mission at a glance:

Mission payloads COSMO-SkyMed Second Generation, CHEOPS, OPS-Sat, ANGELS, EyeSat
Total mission payload mass 3,250 kilograms
Launch vehicle Soyuz-ST No. R15000-008 / Fregat-M / 81KS payload fairing No. U15000-033
Launch site Kourou, ELS
Launch date 2019 December 18

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VS23 mission

During its 23rd launch from the European launch center in French Guiana, the Soyuz-ST rocket will carry five payloads: the Italian Cosmo-SkyMed Earth-observation spacecraft, as the primary payload, and the European Characterizing Exoplanet Satellite, CHEOPS, as its largest secondary passenger. Three small hitchhiker satellites, including a pair based on standard cube-shaped modules 10 centimeters in size, or cubesats, will also be released during the flight.

To accommodate all the payloads, the Fregat upper stage was equipped with an ASAP-S adapter, allowing it to mount the Cosmo-SkyMed primary payload at the top of the structure and the CHEOPS satellite right below its cap-shaped structure. Launching containers with secondary payloads were attached on special adapters along its periphery.



The 2,205-kilogram Cosmo-SkyMed Second Generation satellite is equipped with a powerful imaging radar. The spacecraft was developed by Thales Alenia Space in Italy, for the Italian Space Agency, ASI, and the Italian Ministry of Defense, making it a dual civilian and military mission. The spacecraft's design is based on the Thales' Prima service module which provides power, propulsion, telemetry transmission, thermal- and attitude-control for the satellite.

The second-generation Cosmo-SkyMed constellation should include two Earth-observation satellites, following four first-generation satellites launched between 2007 and 2010. All four previous launches were performed by US Delta rockets.

The Cosmo-SkyMed network was designed to provide all-weather, day-and-night global coverage of the Earth's surface, delivering images of the same area of our planet every 12 hours and each satellite can generate 450 photos per day.

Thales Alenia Space is the prime contractor in the project, responsible for the construction of the two satellites and the development of the high-resolution X-band synthetic aperture radar, X-SAR, carried onboard.

Another Italian firm, Telespazio, was given responsibility for the development the network's ground segment, integrated logistics and operations. The company's ground station in Fucino, Italy, serves as the mission control for Cosmo-SkyMed.

On behalf of the Italian Space Agency, an international operator called e-GEOS distributes the satellite's data to civilian users via its Matera center.

According to e-GEOS, the radar aboard Cosmo-SkyMed is capable of producing images with a resolution from 1 to 100 meters. The satellite is also equipped with a fixed antenna, having electronic steering capabilities that can manage a large number of operative modes for image acquisition and for internal calibrations. The nominal incidence angle (where the system grants the image quality requested) varies between 20 and 59 degrees, e-GEOS said.

The electronics division of another Italian company, Leonardo, supplied the power distribution system for Cosmo-SkyMed itself, as well as for its radar and for the radar's active elements. Leonardo also built gyroscopes, attitude control sensors and solar panels for the satellite.

Arianespace, which was charged with launching the second-generation satellite, did not release any photos of the Cosmo-SkyMed during its pre-launch processing in French Guiana. However, Arianespace circulated an animation showing the deployment of the spacecraft in orbit and the program officials said that the previous-generation Cosmo satellites had operated in orbit with an altitude of 620 kilometers.



The 290-kilogram Characterizing Exoplanet Satellite, CHEOPS, was built by the Spanish division of Airbus for the European Space Agency, ESA. Around a decade in the making, the low-cost space observatory will be used to watch bright nearby stars which are known to have planets, allowing high-precision measurement of their radiuses. The spacecraft will also allow establishing the density of exoplanets with the known masses, providing hints about their internal composition, such as rock or ice.

The spacecraft will target planets ranging from Earth-size to those the size of Neptune, or four times the Earth's radius.

CHEOPS will operate in a 700-kilometer Sun-synchronous orbit. It will be controlled from Mission Operations Center located at INTA, in Madrid, Spain, but the planning of its scientific observations and the processing of the resulting scientific data will be conducted at the Geneva observatory in Switzerland.

CHEOPS was expected to be followed by a far more advanced exo-planet research mission developed in Europe within the Plato project. At the time of the CHEOPS launch, Plato was expected to fly in 2026. Even more advanced Ariel space observatory was also planned in Europe.


According to Arianespace, the 30-kilogram Argos Néo on a Generic Economic and Light Satellite, ANGELS, is the first nanosatellite completely built by French industry. It was jointly financed and developed by the French space agency, CNES, and the HEMERIA industrial group.

The spacecraft carries a miniaturized ARGOS Néo instrument designed to collect and determine the position of low-power signals and messages sent by the 20,000 ARGOS beacons now in service worldwide. The ARGOS Néo receiver 10-times smaller than its predecessor.


Operated by Tyvak company on behalf of ESA, the 7-kilogram OPS-Sat, consisting of three CubeSat modules, will carry a camera for imaging the Earth's surface. The satellite was described as the world's first free-for-use, in-orbit test bed for new software, applications and techniques in satellite control. According to ESA, the 30-centimeter brick-shaped spacecraft was equipped with a computer 10 times more powerful than the calculating device carried on any preceding European mission. It will be used to test new-generation software, ESA said.


The EyeSat is another 7-kilogram cubesat-type payload from CNES assigned to the VS23 mission. Built with the help of students from the Technological Institute University, IUT, in Cachan, France, the EyeSat incorporates three standard CubeSat modules. It will be used for astronomical imaging of the sky, in particular, the photography of the the Milky Way.

Launch campaign

The VS23 mission was previously expected to lift off as early as October 2019, but by September of that year, the launch was postponed until December 2019.

The CHEOPS and ANGELS payloads arrived in French Guiana in October 2019. They were followed by the Cosmo-SkyMed satellite landing in Guiana on November 12. CHEOPS was encapsulated under the ASAP-S adapter, after having been moved to the platform of the transport module on November 29.

On December 9, 2019, Arianespace announced that the integration of the payload had begun at the launch site. By that time, separate assembly, fit-check and fueling milestones cleared the way for the start of payload integration, with CHEOPS to be installed inside the ASAP-S multi-passenger dispenser system and the auxiliary payloads to be assembled on the ASAP-S platform, Arianespace said.

According to the company, the dispenser system was to be integrated on Soyuz’ Fregat upper stage, followed by integration of Cosmos-SkyMed Second Generation atop it. After that, the combined unit was to be encapsulated in Soyuz’ protective payload fairing.

The launch vehicle was rolled out to the pad on December 12 and the next day, the payload section was installed on top of the rocket. The launch readiness review, RAL, took place in Kourou on December 14, clearing the mission for the liftoff.

24-hour delay

The first attempt to launch the Soyuz-ST rocket with Cosmo-SkyMed satellite was being prepared on December 17, 2019, at 5:54:20 a.m. local time (3:54 a.m. EST, 08:54 UTC), however around an hour before the planned liftoff, European officials reported that the launch had to be scrubbed for at least 24 hours due to a software error in the Fregat upper stage. The launch of the VS23 mission was rescheduled for the backup date of December 18, 2019.

Head of Arianespace Stéphane Israël wrote on Twitter that "due to a red at the beginning of the automated sequence of the SYZ launch system, operations are stopped for today. Satellites and Launcher in Full Security. Investigations on going under standard procedures."

Roskosmos then announced that the automated system had detected an issue in the flight control system during the final launch operations. "The cause of the problem is under analysis. The decision had been made to postpone the launch to a backup date: December 18, at 11:54 Moscow Time," Roskosmos said.

According to Arianespace, the automated sequence was interrupted 1 hour 25 minutes before scheduled liftoff. "The Soyuz launcher and its satellite payloads were placed in a fully safe standby mode," the company said.

According to Arianespace, the new launch date was yet to be announced within two hours after the scrub.

In the meantime, a poster on the online forum of the Novosti Kosmonavtiki magazine said that the culprit had been found in the command instrument complex, KKP, in the flight control system of the launch vehicle, not in the Fregat stage. Indeed, NPO Lavochkin, the Fregat's manufacturer, soon issued a statement denying any problems with Fregat. "During the preparation (for launch), all systems of the upper stage worked properly," NPO Lavochkin said, "The preparation of the upper stage for launch was stopped by an automated command. Fregat was brought to an initial state and ready for another processing to launch readiness after resolving the cause of the launch delay."

Before the end of the day on December 17, Head of Arianespace confirmed the new launch time at 08:54:20 UTC on December 18. "Replacement operations are underway for the faulty equipment affected by an outage," Stéphane Israël wrote on Twitter, "A new technical review before fueling of the launch vehicle will occur Dec. 18 at H0-5h."

Launch profile

initial ascent

On December 18, 2019, all operations, except for the live proadcast, seemed to go smoothly and the launch vehicle lifted off as planned.

After a few seconds in vertical ascent from the ELS complex in French Guiana, the rocket headed north to a near-polar orbit. The four boosters of the first stage were dropped as usual two minutes into the flight over the Atlantic Ocean, followed by the separation of the payload fairing around a minute later.

The second stage fired until five minutes into the flight, when the third stage took over. The first stage boosters and the two segments of the payload fairing were projected to fall into the Atlantic south of the Equator and the third stage will impact west of Greenland.

The Cosmo-SkyMed satellite separated first, 23 minutes after launch (4:17 a.m. EST), followed by the CHEOPS spacecraft, which was released 2 hours and 25 minutes after liftoff (6:19 a.m. EST, 11:19 GMT). Cosmo-Skymed was then tracked in a 621 by 623-kilometer orbit with an inclination 97.8 degrees toward the Equator.

According to the European Space Agency, the CHEOPS was to enter contact with ground stations for the first time 2 hours 54 minutes after launch, during a communications window extending from L+169 to L+179 minutes after launch. As expected, the spacecraft contacted ESA's New Norcia ground station and was reported to be in good health.

OPS-Sat cubesat were released 3 hours and 41 minutes after launch (8:05 a.m. EST) and two remaining cubesats were off the Fregat space tug in the following six and a half minutes (8:11 a.m. EST).


VS23 mission timeline:

Elapsed time
Guiana Time
Moscow Time
3:54:20 a.m.
5:54:20 a.m.
Stage I separation
3:56:17 a.m.
5:56:17 a.m.
Payload fairing separation
3:57:36 a.m.
5:57:36 a.m.
Stage II separation
3:59:07 a.m.
5:59:07 a.m.
Stage III separation
4:03:09 a.m.
6:03:09 a.m.
Fregat main engine firing 1 starts
4:04:09 a.m.
6:04:09 a.m.
Fregat main engine firing 1 ends
4:14:33 a.m.
6:14:33 a.m.
Cosmo-SkeMed separation
4:17:03 a.m.
6:17:03 a.m.
Fregat main engine firing 2 starts
4:55:15 a.m.
6:55:15 a.m.
Fregat main engine firing 2 ends
4:55:27 a.m.
6:55:27 a.m.
ASAP-S upper section separation
5:36:00 a.m.
7:36:00 a.m.
Fregat main engine firing 3 starts
5:46:55 a.m.
7:46:55 a.m.
Fregat main engine firing 3 ends
5:47:06 a.m.
7:47:06 a.m.
Fregat main engine firing 4 starts
6:15:15 a.m.
8:15:15 a.m.
Fregat main engine firing 4 ends
6:15:41 a.m.
8:15:41 a.m.
CHEOPS separation
6:19:01 a.m.
8:19:01 a.m.
Fregat main engine firing 5 starts
7:23:35 a.m.
9:23:35 a.m.
Fregat main engine firing 5 ends
7:23:51 a.m.
9:23:51 a.m.
Fregat main engine firing 6 starts
7:56:55 a.m.
9:56:55 a.m.
Fregat main engine firing 6 ends
7:57:12 a.m.
9:57:12 a.m.
OPS-Sat, EyeSat separation
8:05:04 a.m.
10:05:04 a.m.
ANGELS separation
8:07:34 a.m.
10:07:34 a.m.
Fregat main engine firing 7 starts
9:41:55 a.m.
11:41:55 a.m.
Fregat main engine firing 7 ends
9:42:14 a.m.
11:42:14 a.m.
Fregat deorbits
9:46:30 a.m.
11:46:30 a.m.


This page is maintained by Anatoly Zak; Last update: December 18, 2019

Page editor: Alain Chabot; Last edit: December 16, 2019

All rights reserved



insider content



Payload arrangement during VS23 mission. Credit: Arianespace


Artist rendering of the Cosmo-SkyMed satellite deploying in orbit. Click to enlarge. Credit: Arianespace


Artist rendering of the CHEOPS satellite in orbit. Click to enlarge. Credit: ESA


Artist rendering of the ANGELS satellite in orbit. Credit: CNES


OPS-SAT. Click to enlarge. Credit: ESA


EyeSat. Credit: IUT


CHEOPS satellite during pre-launch processing. Click to enlarge. Credit: CNES / Arianespace


Launch container with OPS-SAT satellite during integration with the Fregat upper stage. Click to enlarge. Credit: ESA


Payload adapter is being installed on top of the Fregat upper stage. Click to enlarge. Credit: Arianespace


CHEOPS satellite during pre-launch processing. Click to enlarge. Credit: CNES / Arianespace


Rollout of the Soyuz-ST-A rocket to launch pad on December 12, 2019. Click to enlarge. Credit: CNES / Arianespace


Service tower around the Soyuz rocket shortly before aborted launch attempt on December 17, 2019. Click to enlarge. Credit: Stéphane Israël / Arianespace


Computer-generated rendering of the second stage operation during the launch on December 18, 2019. Click to enlarge. Credit: Arianespace


Computer-generated rendering of the first Fregat burn during the launch on December 18, 2019. Click to enlarge. Credit: Arianespace


Computer-generated rendering illustrating separation of Cosmo-SkyMed satellite during the launch on December 18, 2019. Click to enlarge. Credit: Arianespace


Separation of the payload adapter during the launch on December 18, 2019. Click to enlarge. Credit: Arianespace


Separation of the CHEOPS satellite during the launch on December 18, 2019. Click to enlarge. Credit: Arianespace


Separation of OPS-Sat and EyeSat during the launch on December 18, 2019. Click to enlarge. Credit: Arianespace



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