|Soyuz launches Meridian satellite
After a nearly month-long delay by an electrical problem, military personnel in Plesetsk performed the launch of a Soyuz-2-1a rocket on February 20, 2020. Despite an anomaly during the operation of the third stage, the launch vehicle delivered the second Meridian-M satellite for the Ministry of Defense's Integrated Satellite Communications System, ISSS, nearly seven months after the debut of the upgraded spacecraft.
Mission at a glance:
What was originally expected to be the first Russian launch of 2020 was scheduled to carry the Meridian M No. 19L satellite, denoting the ninth flight-worthy vehicle, because the 10 first numbers are usually reserved for development versions used in ground tests only.
The liftoff of the Soyuz-2-1a rocket with a Fregat upper stage from Plesetsk was originally scheduled on January 24, 2020, at 13:23:04 Moscow Time (5:23 a.m. EST). However, around 09:00 Moscow Time, an electrical problem in the launch vehicle was detected and the launch attempt was shifted to a backup day on January 25, 2020, at 13:18:35 Moscow Time. Still, before the end of the day on January 24, the launch attempted had to be put off for an indefinite period of time.
One industry source said that it would take at least several days to resolve a technical problem. According to another source, a problem with the third stage of the launcher vehicle required the return of the rocket to the vehicle assembly building. Once inside, the specialists began search for an apparent electrical problem in the cabling of the third stage which caused the electrical discharge onto the body of the booster. If the culprit could not be pinpointed, the booster would have to be returned to the assembly factory and replaced with the new one. According to industry sources, the rocket for the Meridian mission had been modified from a three-stage version, which was intended to carry a different payload, and the adaptation of the vehicle for the Fregat upper stage required additional wiring.
As of January 26, the new launch attempt was preliminary scheduled for February 9, 2020, but by January 31, the mission was postponed to February 14, on the condition that the electrical problem would be found, an industry source said. In case of the need for the delivery of the replacement booster, the launch could take place on February 28, at the earliest. In turn, the subsequent launch of the GLONASS-M satellite from Plesetsk would have to wait until March 2020.
By February 1, the specialists failed to locate the problem in the original rocket and the decision was made to deliver the new third stage to Plesetsk. As a result, the launch of the Meridian satellite was preliminary scheduled for February 20 and the launch of GLONASS-M to around March 15, 2020.
On February 6, 2020, the TASS news agency quoted an unnamed industry source as saying that a replacement third stage had been shipped from RKTs Progress in Samara to Plesetsk, while the original booster had been returned to Samara.
After the replacement of the third stage, the launch vehicle was rolled out to the launch pad on the morning of February 18, 2020. The liftoff was set for 11:24:54 Moscow Time on February 20, 2020, (3:24 a.m. EST).
The second attempt to launch the 14F112 Meridian-M satellite (production number 19L) lifted off as planned at 11:24 Moscow Time on Feb. 20, 2020. Several minutes after the planned liftoff, the Russian Ministry of Defense confirmed that the launch had taken place at 11:24 Moscow Time from Pad 3 at Site 43 in Plesetsk. The military then said that the payload section, including a Fregat upper stage and the Meridian-M spacecraft had separated from the third stage of the Soyuz-2-1a launch vehicle as planned at 11:34 Moscow Time.
The routine flight profiles of the Meridian launches typically last around two hours and 15 minutes. Lifting off under the power of the first stage, the Soyuz-2 rocket head southeast across the Russian territory, to align its ground track with an orbit inclined 62.8 degrees toward the Equator. The four boosters of the first stage separate around two minutes into the flight. In the following six minutes, the second and third stages insert the Fregat upper stage and its payload into a ballistic trajectory, just short of orbital velocity.
The Fregat should then fire its engine for 13 seconds to enter an initial parking orbit around 200 kilometers above the Earth's surface. Then, after an almost half-an-hour coasting flight, Fregat's engine fires again to boost the apogee (highest point) of the orbit to an altitude of nearly 36,000 kilometers above the Earth surface. Finally, the third firing lifts the perigee (the lowest point) of the orbit to around 885 kilometers, where the satellite is then released.
Free from its cargo, the Fregat upper stage then fires its engine to enter a disposal orbit, safely away from its former passenger.
The official press-release of the Ministry of Defense said that the Meridian-M spacecraft had been delivered to its planned orbit according to schedule and had established reliable communications with ground control. All systems aboard Meridian-M had functioned normally, the military said. However, RIA Novosti then reported that due to lack of propellant aboard the third stage of the launch vehicle, it shut down a few seconds earlier than planned endangering the outcome of the launch, but, fortunately, the Fregat upper stage had been able to compensate for the lack of velocity. The official TASS news agency then quoted an unnamed industry source as saying that the post-launch evaluation of the incident had indicated that a signal about the lack of propellant had been generated as a result of a software error. According to a posting on the web forum of the Novosti Kosmonavtiki magazine, the third stage stopped operating two seconds prematurely.
Shortly after the launch, the Combined Space Operations Center, CSpOC, in the United States published orbital parameters of the two objects associated with the Meridian-M No. 19L launch:
According to a press-release issued by ISS Reshetnev, the spacecraft manufacturer, the launch vehicle system worked nominally during the delivery of the Meridian satellite and the deployment of mechanical systems aboard the satellite and its orientation toward the Sun had also been performed as planned. Specialists from ISS Reshetnev began testing the functioning of the onboard equipment before transferring the spacecraft to its customer for its planned purpose during its projected life span, ISS Reshetnev said.
However, according to Novosti Kosmonavtiki forum postings, the perigee (of the final orbit) was 8.41 kilometers lower than planned, while the allowable deviation for this parameter was not suppose to exceed 3.5 kilometers in either direction. A special commission was reportedly set up to investigate the anomaly.
The purported Meridian spacecraft in launch configuration with the Fregat upper stage and the payload fairing. Credit: NPO PM