Arianespace Vega launches CERÉS satellites for CNES

by Lee Kanayama

Arianespace’s Vega rocket launched on its third mission of the year with the Capacité de Renseignement Électromagnétique Spatiale (CERÉS) 1, 2, and 3 satellites for the French space agency Centre National d’Etudes Spatiales (CNES). Vega lifted off on November 16, at 6:27 AM Kourou time (09:27 UTC).

This mission was Vega’s 20th overall and Arianespace’s 12th flight of the year. This mission marked the 300th launch of Arianespace’s family of rockets.

Payload and Launch Vehicle

Vega is a four-stage rocket and the smallest vehicle operated by Arianespace. It can lift 2,300 kg to low Earth orbit (LEO) or 1,740 kg to polar orbit.

The rocket is mainly a solid rocket motor-based vehicle, with three of its four stages using solid propellant.

Vega VV16 before launch. (Credit: Arianespace)

Vega’s first stage uses the P80 solid rocket motor. The P80 motor is a large, single-piece design that can burn for 113 seconds and produce 3,015 kN of thrust in a vacuum. The motor is three meters in diameter with an overall length of 11.2 meters.

The second stage is powered by a Zefiro-23 solid motor. The Zefiro-23 can burn for 78 seconds and has a thrust of 1,120 kN in a vacuum. The third stage is the Zefiro-9 solid motor, which can burn for 120 seconds with a thrust of 317 kN. The second and third stages are both 1.9 meters in diameter. However, the second stage is taller at 8.39 meters long while the third stage is 4.12 meters long.

The Attitude & Vernier Upper Module (AVUM) is the fourth and final stage of the Vega rocket. The AVUM, the only liquid-propellant stage of the Vega, is powered by the re-ignitable Russian RD-869 hypergolic engine. The RD-869 can produce 2.45 kN of thrust and uses unsymmetrical dimethylhydrazine (UMDH) and nitrogen tetroxide (NTO) as its propellants. The AVUM uses hydrazine thrusters to provide roll and attitude control, and the stage is used to place satellites into their final orbit.

The fairing of Vega is 7.88 meters long and 2.6 meters in diameter.

Vega launched from the Guiana Space Center from the Ensemble de Lancement Vega, or ELV, pad. This pad is the oldest at the Guiana Space Center, first used for the Europa-II rocket. Following the end of the Europa program, ELV was later used for the Ariane 1, 2, and 3 rockets until Ariane 3 was retired in 1989. It was later refurbished for Vega in 2001 and was first used for the new launcher in 2012.

Since its introduction, Vega has flown 19 times with 17 successes. From 2012 to 2019, Vega successfully completed 14 flawless missions, until its first failure on the Vega Vehicle 15 (VV15) mission. Its second failure was seen on VV17 in 2020. Since Vega’s last failure, VV18 and VV19 have both flown successfully, carrying the Pleiades-Neo 3 and 4 satellites and rideshare payloads on their respective flights.

Artist impression of CERÉS while in orbit. (Credit: CNES)

VV20 carried three CERÉS satellites for the French military. CERÉS is a series of three closely positioned Electronic Intelligence (ELINT) satellites. The satellites will be used to detect and locate ground signals, along with ground control and user ground segments. Built by Airbus, each stellite has a mass of 446 kg. The CERÉS program incorporates lessons learned from the Essaim and ELectronic Intelligence by SAtellite (ELISA) programs.

Essaim (“swarm” in French) were a set of four technology demonstrators launched by an Ariane 5G+ in 2004. The satellites were based on the Myriade satellite bus and weighed 120 kg. The main goal of these satellites was to collect and map signal intelligence across the world. The satellites were deactivated in 2010.

The second demonstrator program, ELISA, was another set of four satellites also based on the Myriade bus. These satellites were launched on a Soyuz ST-A mission in 2011. The ELISA program was used to demonstrate the future use of ELINT for mapping positions of radar and other transmitters throughout the world. ELISA is still in orbit today.

Airbus won the contract to build the CERÉS satellites in 2015 after the success of the ELISA program. Arianespace was contracted to launch the CERÉS satellites in 2016.

The three satellites were originally contracted to launch on the upgraded Vega-C rocket before being moved to the original Vega variant. The CERÉS satellites are three of the four French military satellites set to launch by Arianespace in 2021. The first satellite, Syracuse-4A, was launched in October 2021 on the VA255 flight of Ariane 5.

The satellite’s payload adaptor was delivered to French Guiana in July 2021, with the satellites themselves following in September. Also in September, following the launch of VV19, the P80 for VV20 was placed on the launch stand at ELV. The other three stages were stacked on the rocket shortly after.

The payloads were integrated on the payload adaptor in October before encapsulation in the 2.6 meter diameter fairing. In November, the assembly was placed onto the Vega rocket. The Launch Readiness Review (LRR) was completed on November 13, and Vega was cleared for launch.


VV20 launched from ELV at 6:27 AM Kourou time, 09:27 UTC on Tuesday, November 16. With Vega not using any cryogenic propellants, there is no pre-launch fueling normally seen with most rockets. As such, a Vega countdown focuses on avionics activations and checkouts, day of launch software uploads for upper-level wind patterns, flight trajectory targets, and removal of safety devices from the vehicle.

Vega was ready to launch at T-50 minutes, with final weather checks at T-10 minutes and Vega entering terminal count at T-4 minutes.

At T0, the P80 motor ignited, lifting Vega toward orbit. The rocket began a pitch maneuver to reach an azimuth that will deliver it into a 75-degree inclination orbit.

Launch of Vega VV19. (Credit:ESA/Arianespace)

The motor burned out at T+1 minute 53 seconds. A few seconds later, the P80 separated and the Zefiro-23 motor will ignited.

At T+3 minutes 39 seconds, the Zefiro-23 burned out and separated. The Zefiro-9 ignited shortly after stage separation. The payload fairing separated at T+3 minutes 57 seconds. The Zefiro-9 third stage continued to burn for about three more minutes and then separated.

After a one-minute coast, the AVUM will ignite for the first of three burns. After the AVUM conducts its orbital insertion burn, it will coast until T+53 minutes 29 seconds, when it will reignite. It burns for about a minute to place it into a roughly 670 km orbit.

At T+56 minutes 44 seconds, the three CERÉS satellites separated from the AVUM in a Sun-synchronous orbit.

The third stage will reignite for its final time at T+1 hour 48 minutes for a deorbit burn.

After VV20, Vega will launch one more time before the Vega-C rocket comes online. Vega-C is an upgraded version of the Vega rocket using a brand-new first and second stage. The first stage will be the P120C (also used on the Ariane 6 rocket as that vechicle’s side boosters) while the second stage will be the new Zefiro-40.

The third and fourth stages are upgraded variants of the ones currently used on Vega. The fairing used on Vega-C will use a new 3.3-meter diameter configruation.

Lead image: Vega VV19 before launch. (Credit:ESA/Arianespace)

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