Soyuz delivers Falcon Eye-2
After two 24-hour delays, personnel at the European launch site in French Guiana finally launched a Soyuz ST-A rocket with the Falcon Eye-2 reconnaissance satellite on December 1, 2020. The spacecraft ordered by the armed forces of the United Arab Emirates, UAE, has been grounded since March by the coronavirus pandemic.
Soyuz VS24 mission at a glance:
History of the mission
On December 9, 2014, the European consortium Airbus Defense and Space announced that it had been selected by the Armed Forces of the United Arab Emirates to be the prime contractor in the development and launch of two "high-performance" optical observation satellites. The contract for the project was signed in August 2014 and entered force at the time of the announcement, the Airbus said. In addition to the construction of the satellite, the company also got the responsibility for the development of a ground system for monitoring, receiving and processing images from the spacecraft as well as training the UAE's specialists to operate the satellite after its deployment in orbit.
At the same time, France-based Thales Alenia Space announced that it had won a contract from the UAE's military to build a "very-high resolution" optical payload for the Falcon Eye pair, as well as the data transmission system and the image-processing system. The company was also responsible for the co-engineering and validation of the overall system.
The spacecraft was reported to be designed for 10 years of operation in space.
The Falcon Eye-2 satellite and its Fregat upper stage are encapsulated under a payload fairing. The top (aperture) section of the spacecraft was cropped from all publicly released visuals.
The original Falcon Eye satellite was launched on July 11, 2019, but it failed to reach orbit because of a failure of the Vega launch vehicle during the operation of its second stage. The government of UAE then made the decision to switch the launch of the follow-on spacecraft to the Soyuz rocket operated by the European consortium Arianespace from its site near Kourou, French Guiana.
Arianespace was mostly mum about the preparations for the mission, but Head of Roskosmos Dmitry Rogozin boasted on his Twitter account on March 2, 2020, that the Soyuz rocket for the launch of the Falcon Eye-2 reconnaissance satellite had been rolled out to the launch pad in French Guiana and that the liftoff had been scheduled at 04:33:28 Moscow Time on March 6.
Delay of the first launch attempt
The Soyuz ST-A rocket, carrying Falcon Eye-2 satellite, was originally scheduled to lift off from the ELS launch facility in French Guiana on March 5, 2020, at 8:33:28 p.m. EST (04:33:28 Moscow Time on March 5) during an instantaneous window. It would be 10:33 p.m. in French Guiana.
However before the end of the business day in Moscow on March 5, the TASS reported, quoting an unnamed industry source, that the mission had to be postponed until the next day due to issues with the upper stage. There was a possibility that the launch could pushed back even further, but the final decision would not be made before repeating the integrated tests of the launch vehicle, TASS said.
Later in the day, Arianespace published a statement saying that "due to additional checks to be performed on the Fregat upper stage of the Soyuz flight VS24, the launch initially scheduled for March 5, 2020 from the French Guiana Space Center is postponed. The launch vehicle and its satellite payload have been placed in stand-by mode and maintained in fully safe conditions," the company said. Since the announcement had not contained a new launch date, it appeared that the mission had been postponed indefinitely.
On March 6, a Russian industry source said that the mission was postponed until early April due to customer's demand to replace Fregat upper stage on the rocket, even though Russian specialists proposed to fix the problem on the current booster. The Fregat stage, originally slated to carry the CSO-2 satellite and already at the launch site, would be used as a replacement, the source said. The launch of CSO-2 was previously planned for April 10.
According to a post on the Novosti Kosmonavtiki web forum, lack of signal on one of three channels controlling fuel supply to a DMT thruster of the Fregat stage caused the delay. A switch controlling system was a possible culprit, the poster said.
On March 15, 2020, due to the coronavirus pandemic, the French space agency, CNES, operating the Guiana Space Center, ordered to stop ongoing launch campaigns at the site and all unfinished construction. The only exception were the operations to bring the launch vehicles, payloads and facilities in safe condition and their monitoring.
On March 19, a Nordwind's Boeing-777-200 evacuated 246 Russian specialists from French Guiana to Moscow. A group of 21 people stayed longer to conduct drainage of maximum possible amount of propellant from the Fregat-M stage, so it could be stored without a supervision of the Russian team.
As of April 10, the remaining Russian personnel was scheduled for evacuation from French Guiana between April 27 and April 30, 2020. On April 25, Roskosmos confirmed that the final group of nine specialists had landed at Moscow's Sheremetievo airport at 14:30 Moscow Time on that day.
As of early April, the launch of Falcon Eye-2 was tentatively scheduled for September 15, but by the middle of May, the launch was postponed until October 1, 2020, and, in June 2020, it was postponed until October 17. By September 2020, the mission was postponed until November 3 and by the middle of October, it slipped until the end of November 2020.
The launch readiness review was conducted on November 24 clearing the rocket for the rollout to the launch pad on November 25 at 12:30 Moscow Time. The rollout started as planned on November 25, with the liftoff planned on November 28, 2020, at 22:33 local time (01:33 UTC on November 29). Mission officials met at 13:00 Paris on November 27 for the launch readiness review, which cleared the mission for final processing. Another review of the mission status took place on the morning of November 28 and the decision was made to postpone the launch for 24 hours due to weather conditions at the launch site.
November 29 launch attempt
A Soyuz rocket with the Falcon Eye-2 satellite shortly before the scrubbed launch attempt on evening of November 29, 2020.
On November 29, Arianespace confirmed that the launch readiness review earlier that day authorized the start of operations for the final countdown. However around five minutes before the scheduled liftoff on November 29, the launch was postponed for 24 hours due to risk on lightning.
November 30 launch attempt
Another attempt was made on November 30, when weather was reported to be good, but around five minutes before the planned liftoff, the final countdown had to be stopped due to a technical problem. According to Arianespace, the launch was scrubbed due to an off-nominal reception of telemetry by the range safety personnel. (That group of specialists from the French Space Agency, CNES, is responsible for the emergency engine cutoff aboard the rocket in case of a considerable deviation of the vehicle from its prescribed trajectory. The operation is unique to the ST variant of the Soyuz-2 rockets based in French Guiana.)
Finally the liftoff!
The new launch attempt was set for December 1, 2020, at 10:33 p.m. local time and this time went without a hitch.
Countdown milestones for the VS24 mission:
Launch profile of the Falcon Eye-2 mission
The mission followed a typical flight profile required to deliver an observation satellite into near-polar orbit, which takes the spacecraft from North Pole to the South Pole and back, with the orbital plane of the mission nearly perpendicular to the plane of the Equator. According to Arianespace, the flight targeted a Sun-synchronous orbit with an altitude of 611 kilometers, meaning that the satellite periodically appeared over the same region on Earth at the same time of the day and thus guaranteeing consistent lighting conditions over the photographed areas.
To reach the polar orbit, after a few seconds in vertical ascent over the South-American coast, the Soyuz rocket headed north over the Atlantic Ocean. The four boosters of the first stage were dropped around two minutes into the flight, followed by the separation of the payload fairing around a minute later. As the rocket progressed northward, it was tracked subsequently from the Galliot ground station in French Guiana, followed by the Bermuda station in the Atlantic Ocean and Saint Hubert in Quebec, Canada.
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 fell into the Atlantic south of the Equator and the third stage impacted west of Greenland.
The Fregat upper stage then maneuvered to insert the 1,190-kilogram satellite into its target orbit. A total of two Fregat engine firings were pre-programmed before the release of the satellite.
The first maneuver lasting 444 seconds (7.4 minutes) took place over the Northern Atlantic, inserting the vehicle into an initial elliptical orbit. Around that time, the Fregat and its payload went out of communications range for 32 minutes, as they crossed the Arctic and began heading southward over the Eastern Hemisphere. When the vehicle reached the apogee of its transfer orbit less than 55 minutes after launch, the Fregat fired for the second time for 33 seconds to made the orbit circular at the target altitude.
Around that time, the Fregat was within communications range of the ground station in New Norcia, Australia, which was able to confirm the separation of the satellite from the upper stage which took place as scheduled 58 minutes and 45 seconds after liftoff.
The empty Fregat stage was then programmed to swing around the Antarctic and begin trekking northward over the Western Hemisphere. As it begins the second orbit around the Earth, the stage will re-appear over the Atlantic ground stations, allowing to downlink the telemetry from the stage.
Finally, around 1 hour and 50 minutes after leaving Earth, Fregat will fire its engine for the third time. The maneuver lasting 61 seconds will direct the stage to a fiery destruction in the Earth's atmosphere. Shortly before the original launch attempt, the authorities published a warning to air and sea traffic to avoid a remote region of the Indian Ocean, over which Fregat debris were expected to be scattered during the reentry.
The VS24 mission timeline:
Payload configuration during the launch of the Flacon Eye-2 satellite on the Soyuz rocket. Credit: Arianespace
Rare view of Falcon Eye-2 satellite still in process of orbital insertion by the Soyuz/Fregat system (aperture area of the spacecraft is covered as usual). Click to enlarge. Credit: ESA
The Soyuz rocket for the second Falcon Eye mission is being erected on the launch pad in French Guiana. Click to enlarge. Credit: ESA
Access tower is being prepared for withdrawal from the Soyuz rocket ahead of a scrubbed launch attempt on November 29, 2020. Click to enlarge. Credit: ESA
Soyuz lifts off from French Guiana on December 1, 2020. Click to enlarge. Credit: CNES
Ground track of the Falcon Eye-2 mission during the first burn of the Fregat upper stage lasting 444 seconds. Click to enlarge. Credit: ESA
After passing over two ground stations in the Atlantic, the Fregat will be out range of communications with ground control for 32 minutes. Click to enlarge. Credit: ESA
Second firing of the Fregat upper stage lasting 33 seconds will take place over the Eastern Hemisphere. Click to enlarge. Credit: ESA
Falcon Eye-2 should separate from the Fregat upper stage within a communications range of a ground station in Nova Norcia, Australia. Click to enlarge. Credit: ESA
During a pass over Australia, telemetry will be downlinked from the Fregat upper stage. Click to enlarge. Credit: ESA
More telemetry will be downlinked from Fregat when its reappears over the Atlantic. Click to enlarge. Credit: ESA
The third Fregat engine firing, lasting 61 seconds will send the stage to burn up in the Earth's atmosphere. Click to enlarge. Credit: ESA
Mission control will have the final opportunity to downlink data from the Fregat upper stage immediately after its third maneuver. Click to enlarge. Credit: ESA