Soyuz launches commercial satellite cluster
After a 48-hour delay by a technical problem, Russian personnel at Baikonur Cosmodrome, Kazakhstan, successfully launched a Soyuz-2-1a rocket on March 22, 2021, delivering the CAS-500-1 remote-sensing satellite for South Korea and 38 hitchhiker payloads from 18 countries in three different sun-synchronous orbits.
Soyuz rocket launch with the CAS-500-1 satellite at a glance:
The "ridershare" mission
Roskosmos won the contract for the launch of two CAS-500 satellites in August 2017. The 500-kilogram spacecraft were developed at the Korean Aerospace Research Institute, KARI, for high-resolution multi-spectral imaging of the Earth's surface. The project, under development since 2015, was reported to cost $143.8 million.
The launch of the Soyuz-2-1a rocket with the CAS-500-1 satellite was originally planned in the third quarter of 2020. The preparation campaign was delegated to GK Launch Services, which was formed by Glavkosmos, a commercial subsidiary of Roskosmos State Corporation, and the Kosmotras company that had previously marketed discontinued Dnepr missions.
The remaining payload capacity aboard the Soyuz was marketed for the so-called "ridershare" mission, offering multiple customers to place hitchhiker payloads on the Fregat upper stage and release them in orbit after the separation of its primary passenger.
In the course of the mission planning and preparation, the exact number of booked passengers had changed, but according to a list issued by Glavkosmos around 10 days before the scheduled launch, a total of 38 secondary payloads from 18 different countries were onboard alongside the CAS-500-1. Seven spacecraft were classified as small satellites, 24 as cubesats and 6 as nanosats:
NanoSatC-BR2, KMSL, Pumbaa, Timon and the BeeSat cluster share the ride to orbit inside QuadPack deployer No. 1.
A trio of of Russian cubesat payloads was packed into the so-called 4 by 3U + 6U deployer provided by the Russian company Aerospace Capital:
Aerospace Capital also supplied another 4 by 3U deployer for another group of cubesats, including:
A few payloads previously registered for the flight apparently did not make it to the launch campaign and had to be replaced with dummies to preserve the geometry and the center of gravity of the stack during the flight. The missing payloads included the NAPA-2 satellite from the Royal Air Force of Thailand and the Vigoride spacecraft mockup from NPO Lavochkin.
A payload section with the CAS-500-1 spacecraft and secondary satellites is being prepared for encapsulation under its payload fairing on March 12, 2021.
Summary of payloads during the launch of CAS-500-1 satellite:
Preparations for flight
The first and second stages of the Soyuz rocket for the CAS-500-1 satellite during assembly at Site 31 in Baikonur on March 5, 2021.
On January 11, 2021, GK Launch Services announced that the Fregat upper stage, ELSA-d, DMSAT-1, UNISAT-7, three GRUS and a Fukui Prefectural Satellite arrived at the Baikonur Cosmodrome in preparation for launch on March 20.
The CAS-500-1 satellite was delivered to Baikonur on January 24, 2021. Autonomous electric tests of the spacecraft had been completed by February 20 and it was being prepared for fueling planned from February 21 to February 27.
By March 10, the CAS-500-1 satellite and the truss with the secondary payloads were integrated with their Fregat upper stage and ready for the installation of the payload fairing, which was completed on March 12.
On March 14, the payload section was integrated with the third stage of the Soyuz rocket and by March 15, the resulting upper composite was connected to the pre-assembled first and second stages, completing the integration of the launch vehicle. On March 16, the State Commission cleared the rocket for the rollout to the launch pad at Site 31. The rocket left the assembly building around 05:30 Moscow Time on March 17, 2021. After installation of the vehicle in vertical position, the first day on the pad was spent on autonomous tests of the payload, the rocket stages and ground equipment. At the end of the second day of on-pad preparations on March 19, Head of Roskosmos Rogozin announced the launch vehicle had passed the integrated tests with flying colors.
Soyuz-2-1a with CAS-500-1 satellite shortly after installation on the launch pad on March 17, 2021.
Key operations of the pre-launch operations were conducted during the night from March 19 to March 20. On the morning of March 20, the State Commission overseeing the preparations met and gave the green light to the fueling of the rocket's three booster stages and confirming the launch time. The loading of the kerosene aboard the first and second stages started at 05:03 Moscow Time. However, less than an hour from the planned liftoff on March 20, the launch attempt had been scrubbed due to technical reasons. The access gantry remained in place around the rocket at the time of its planned retraction normally conducted 30 minutes before liftoff. Several minutes after that milestone had not been met, the official live broadcast was concluded with a report about a technical problem requiring the delay.
Within an hour after the scrub, Roskosmos announced that the launch attempt would be repeated in 24 hours. Around the same time, the official RIA Novosti news agency quoted Roskosmos head as saying that a spike in the electric current prompted caution and required to postpone the launch. An industry source told RussianSpaceWeb.com that a power interruption from the ground network had caused the scrub. South Korea's Ministry of Science and ICT issued a statement implying that the problem had been detected during the final checks of the flight control system aboard the Fregat upper stage.
By the end of the day on March 20, Roskosmos announced that the meeting of the State Commission that had reviewed the discovered technical problem, made a decision to make the next launch attempt on the morning of March 22, 2021. The announcement also quoted the Director General of Roskosmos Dmitry Rogozin as saying that "in Baikonur, the State Commission made a decision to repeat the tests of the Control Setup of Launch Readiness, KNSG, for the Fregat upper stage on March 21. On the condition of the positive outcome of the KNSG mode, the launch is planned for Monday, March 22."
The decision was for the second fueling of the rocket was expected to be made by a State Commission meeting at 07:00 local time (05:00 Moscow Time) on March 22 to enable the liftoff at 09:07 Moscow Time, Glavkosmos said.
Soyuz lifts off on a second try
The initial three-stage ascent of the Soyuz-2-1a rocket was largely routine with the liftoff under the simultaneous thrust of the four peripheral engines of the first stage and the central engine of the second stage. Somewhat unusually, the vehicle headed north and slightly west to align its ground track with a near-polar orbit inclined more than 97 degrees toward the Equator.
The four strap-on boosters of the first stage consumed their propellant first and dropped off 117.77 seconds after liftoff. In the meantime, the core booster continued firing until 4.7 minutes into the flight and separated at T+287.53 seconds, followed by the split and separation of three segments of the third stage skirt at 289.09 seconds and the halves of the payload fairing at 290.23 seconds. These three milestones were timed in close proximity from each other to ensure that all the debris fell in the designated drop zone along the mission's ground track.
Several days before planned launch, authorities in Sverdlovsk and Perm Regions of Russia issued a warning to local population for the rural Karpinsk District from March 20 to March 24, 2021. The projected impact site was bordered by a polygon formed by points located 20 kilometers north of the town of Kytlym, 10-12 kilometers northwest of Kakvinskie Pechi, 17 kilometers west of Sosnovka, 4-5 kilometers south of Denezhkin Kamen reserve, 2-3 kilometers north of the Konzhakovsky Gorge.
In the meantime, the third stage of the rocket ignited its engine moments before the separation of the second stage, firing for a few seconds through a lattice structure connecting the two boosters until the core stage dropped off. The third stage kept firing until T+525.75 seconds, cutting off just before it reached an orbital velocity in order to make sure it did not reach orbit and instead splashed down in the ocean. The third-stage booster separated from the Fregat fourth stage at T+528.7 seconds in flight.
Upper stage maneuvers
Shortly after entering its ballistic path, the Fregat upper stage was programmed to fire its main engine for the first time, reaching an initial parking orbit around the Earth. Shortly after the planned maneuver, Roskosmos confirmed that the first firing had gone as planned.
In the following two hours, the Fregat performed a series of maneuvers to enter three different sun-synchronous orbits. The CAS-500-1 satellite was to be released first into a 498.7-kilometer orbit with an inclination of 97.40 degrees toward the Equator at 10:10 Moscow Time or one hour and three minutes after liftoff from Baikonur and after two Fregat engine firings.
Around 10:50 Moscow Time, Roskosmos confirmed that CAS-500-1 had successfully separated from the Fregat. Glavkosmos also said that specialists from KARI had established contact with the satellite.
The Fregat then maneuvered to a 592-kilometer orbit with an inclination 97.73 degrees, where four GRUS satellites were released during a two-minute period from 11:35 to 11:37 Moscow Time. After another maneuver to enter the 550-kilometer orbit with an inclination 97.57 degrees toward the Equator, the remaining secondary payloads were separated from Fregat between 13:13 and 13:43 Moscow Time.
Roskosmos confirmed that all satellites had been successfully deployed.
CAS-500-1 during pre-launch processing. Click to enlarge. Credit: Roskosmos
CAS-500-1 satellite after integration with the payload adapter. Click to enlarge. Credit: GK Launch Services
The Unisat-7 platform during pre-launch processing. Click to enlarge. Credit: GK Launch Services
GRUS satellites and their processing team after the completion of the spacecraft integration with the payload adapter. Click to enlarge. Credit: GK Launch Services
An ELSA-d duo during pre-launch processing. Click to enlarge. Credit: Roskosmos
Artist rendering of ELSA-d satellites performing proximity operations in orbit. Click to enlarge.
Beesat team from Technical University of Berlin with their payloads. Click to enlarge. Credit: TU Berlin/F. Baumann
Installation of the OrbiKraft-Zorky into its launch container. Click to enlarge.
A pre-launch assembly of Tunisian Challenge One satellite. Credit: GK Launch Services
The DMSat-1 satellite is being prepared for integration with the Fregat upper stage in Vostochny. Credit: GK Launch Services
The Adelis-Samson satellite. Credit: GK Launch Services
A pair of Kepler satellites (6 and 7). Click to enlarge.
CAS-500-1 satellite (top right) is being prepared to be integration with the rest of the payloads. Click to enlarge. Credit: Roskosmos
A fully assembled payload section with the CAS-500-1 satellite. Click to enlarge. Credit: Roskosmos
The CAS-500-1 satellite and secondary payloads are encapsulated under a payload fairing. Click to enlarge. Credit: Roskosmos
Integration of the payload section with the third stage of the launch vehicle on March 14, 2021. Click to enlarge. Credit: Roskosmos
A Soyuz-2 rocket leaves the vehicle assembly building at Site 31 on the morning of March 17, 2021. Click to enlarge. Credit: Roskosmos
A Soyuz-2 is erected on the launch pad. Click to enlarge. Credit: Roskosmos
A Soyuz-2 shortly after installation on the launch pad at Site 31 on March 17, 2021. Click to enlarge. Credit: Roskosmos
Soyuz-2 lifts off on March 22, 2022. Click to enlarge. Credit: Roskosmos