Soyuz 2.1a launch

CAS500-1 & rideshare | Soyuz 2.1a/Fregat-M

Feature image credit: Gelio
Lift Off Time
March 22, 2021 – 06:07:12 UTC | 11:07:12 ALMT
Mission Name
CAS500-1 & rideshare
Launch Provider
(What rocket company launched it?)
GK Launch Services
(Who paid for this?)
Korea Aerospace Research Institute (KARI)
Soyuz 2.1a / Fregat-M
Launch Location
Site 31/6, Baikonur, Kazakhstan
Payload mass
~800 kg (~1,800 lbs)
Where did the satellites go?
Sun-synchronous orbit 497.8 km (~310 miles)
Did they attempt to recover the first stage?
No. Soyuz rockets don’t have this capability.
Where did the boosters land?
They crashed into the steppes of Kazakhstan
Did they attempt to recover the fairings?
No. Soyuz rockets don’t have this capability.
Were the fairings new?
This was the:
– 408th launch from site 31/6
– 116th launch of a Soyuz-2 rocket (any variant)
90th flight of a Soyuz-2 rocket with Fregat upper stage
3rd mission for the Baikonur launch site in 202
– 23rd orbital launch for 2021
Launch replay
Official livestream

How did it go?

GK Launch Services launched a Soyuz 2.1a rocket with a Korean satellite CAS500-1, and several other rideshare partners, to a Sun-synchronous orbit of 497.8 km (~310 miles) altitude.

The main payload was an Earth-observation satellite, which will now study the Earth using both panchromatic and multispectral modes of operation.

So who are GK Launch Services?

GK Launch Services is a company established by Glavkosmos, itself a subsidiary of ROSCOSMOS State Space Corporation, in partnership with International Space Company Kosmotras. It specialises in set-up and management of Soyuz-2 commercial launches from Russian spaceports (in Russia or Kazakhstan). As an illustration, between 2009 and 2017, Glavkosmos has launched more than 90 payloads using the Soyuz 2 rocket.

The CAS500-1 & others mission


The Compact Advanced Satellite 500 (CAS500) is designed to perform precision ground observation, using its electro-optical sensors. According to KARI, “The CAS500 series plans to apply the standard platform developed for the CAS500-1 to the subsequent CAS500 series and carry various localized payloads.”

CAS500 satellite
CAS500 satellite (Credit: KARI TV)

The satellite is 1.9 m wide and 2.9 m long. Specifically, its electro-optical sensors can operate in both panchromatic and multispectral modes, with stated resolution of “0.5 m-class / 2.0 m-class respectively.” The sensing instrument is known as the  Advanced Earth Imaging Sensor System (AEISS-C).

To illustrate, successive passes of a CAS500 satellite, or passes by a pair of CAS500 satellites, over a region allows swaths of imagery to be taken from different angles during the different passes. Combining the data from the multiple passes together allows reconstruction of the 3D terrain back on the ground – in considerable detail.

CAS500 imaging the ground from orbit
CAS500 imaging the ground from orbit (Credit: KARI TV)

CAS500-1 will be deployed into its orbit first (1 hour 3 minutes after launch).

Next, the additional, rideshare, satellites will then be deployed into two separate orbits. Firstly the second orbital deployment takes place over a two minute window, about 2 hours 30 minutes following launch. Finally, the third orbital deployment is expected to occur over a period between 4 hours 8 minutes and 4 hours 38 minutes after launch.

GRUS-1B, 1C, 1D & 1E

Each of these is an Earth observation satellite with a mass of 80 kg. They have the ability to measure light in panchromatic and multispectral modes, similar to CAS500. In this case however, the resolution is 2.5 m in panchromatic mode and 5 m in multispectral mode. The satellites were built by Axelspace, which also owns most of them.

GRUS-1A was launched on a previous Soyuz-2.1a back in 2018. GRUS-1D is identical to its siblings, but is intended for a different purpose. Also known by the name the Fukui Prefectural Satellite, it was built for FSTRA.

The satellites are intended to be used for several activities such as agriculture, fishery, forestry, mapping, Geographical Information Systems (GIS) and monitoring of natural disasters, such as hurricanes and earthquakes.

UniSat 7

This is a technology demonstration system for in turn launching smaller payloads such as CubeSats. Originally intended to fly on a Dnepr rocket (which is no longer in service), it has been delayed from 2016. It has a mass of 32 kg.

It dispensed several of the additional payloads named below, such as:

  • BCCSAT 1 (1U)
  • FEES (0.3 U)
  • WormSail (2U) CubeSats, and
  • DIY 1 / Arduiqube(1p)
  • SMOG 1 (1p)
  • STECCO (6p)
  • Unicorn 1 (1p) PocketQubes.

A PocketQube unit (1p) of size is 5 cm x 5 cm x 5 cm. A CubeSat unit (1U) of size is 10 cm x 10 cm x 10 cm.

Challenge ONE

This is the first satellite from Tunisia. It is a research and development program that provides an Information Technology (IT) platform. The satellite also has a wide-angle camera on board. It was built by Tunisia’s own Telnet company (not to be confused with any other company with the same name, or the Internet protocol) with support from Russia.

AfricaNews reported that “[t]here are many possible uses for Challenge One, ranging from remotely activating solar pumps in the Sahara to tracking livestock crossing Tunisian borders into Algeria or Libya”.

Unicorn 1

This is the first satellite for Alba Orbital, a company based in Glasgow, Scotland. It is a demonstration and pathfinder towards the follow-up Unicorn 2 platform.

It is a 2p sized spacecraft, with its own onboard payload volume of 1p. On this flight, the payload is an S-band Inter Satellite Link (ISL) radio. The satellite will attempt to perform the first inter-satellite transmission between a PocketQube in a Low Earth Orbit (SSO in this case) and another satellite in geostationary orbit.

Additional payloads

Additional rideshare payloads (of which there are many) that were onboard this flight are listed at the end of this article.

Render of the CAS500-1 & rideshare payloads on the Soyuz upper stage
Render of the CAS500-1 & rideshare payloads on the Soyuz upper stage (Credit: Roscosmos)

Soyuz rocket

Introduced in 1966, Soyuz has been the workhorse of the Soviet/Russian space program. The first launch of the Soyuz-2.1a version on November 8, 2004 from the Plesetsk Cosmodrome represented a major step in the Soyuz launch vehicle’s development program. Fregat is the upper (4th) stage of Soyuz 2.1, and it first flew in the year 2000.

Evolution of the R7 / Soyuz rocket family
Evolution of the R7 / Soyuz rocket family (Credit: NASA / Peter Gorin / Emmanuel Dissais)

The Soyuz version currently being used for most satellite launches (as distinct from crewed capsules or cargo capsules to the ISS) is a four-stage launch vehicle, which consists of:

  • four side boosters (first stage)
  • a central core booster (lit together with the side boosters at take-off)
  • a third (central) stage
  • the re-startable Fregat “upper” stage (fourth stage)

It also includes a payload adaptor/dispenser and fairing.

Side boosters

The side boosters’ RD-107A engines are powered by liquid oxygen and kerosene, which are the same propellants used on each of the lower three stages. The kerosene tanks are located in the cylindrical part and the liquid oxygen tanks in the conical section. Each engine has four combustion chambers and four nozzles.

During side booster separation, the boosters perform a well-known pattern, in which they peel off and cartwheel outwards! This is known as the “Korolev cross”, named after Sergei Korolev, the Chief Design Engineer of the USSR space program in the 1960s.

Korolev cross during side booster stage separation on a Soyuz launch
“Korolev cross” seen during side booster stage separation on a Soyuz launch.

Center core stage

The center core stage is fitted with an RD-108A engine, and also has four combustion chambers and four nozzles. It also has four vernier thrusters, used for three-axis flight control once the side boosters have separated. The third stage engine’s thrust enables the stage to separate directly from the central core. This is called “hot staging”.

Third stage

The third stage uses either an RD-0110 engine in the Soyuz ST-A (2-1a) version, or an RD-0124 engine in the ST-B (2-1b) version. This flight is using a 2-1a vehicle, so in this case the stage has an RD-0110 engine.

RD-0110 Soyuz third stage engine
RD-0110 rocket engine Credit: Andrew Butko under Creative Commons license

Fregat upper stage

Flight qualified in 2000, the Fregat upper stage is an autonomous and flexible stage that is designed to operate as an orbital vehicle. It extends the Soyuz launcher’s capability, now covering a full range of orbits (LEO, SSO, MEO, GTO, GEO and Earth escape). Fregat is independent from all the other stages, as it has its own guidance, navigation, attitude control, tracking, and telemetry systems! The stage’s engine uses storable propellants – UDMH (unsymmetrical dimethylhydrazine) and NTO (nitrogen tetroxide) – and can be restarted up to 20 times in flight, so that it can carry out very complex missions.

The Fregat upper stage is encapsulated in a fairing with the payload and a payload adaptor/dispenser.

Trivia / fun fact

This rocket featured a novel paint scheme, to mark the 60th anniversary of Yuri Gagarin’s historic first orbital crewed flight. Traditionally, Soyuz rockets have used a gray and orange paint scheme. This rocket, however, was painted in white and blue. This is in reflection of the colors used on the Vostok 1 flight on April 12, 1961. (This date is now honored annually with world-wide “Yuri’s Night” parties.)

Soyuz 2 in white and blue livery
Soyuz 2 in white and blue livery (Credit: Yuzhny Space Center / Roscosmos)

The color scheme appears to have been chosen by GK Launch Services, meaning that future Soyuz rockets from GK will continue to use this new scheme.

Additional payloads from 18 countries

3B5GSATIoT / 5G NanoSat
ADELIS-SAMSON 1, 2 & 3Israeli satellites demonstrating formation flying
BCCSAT 1Multispectral satellite built by students in Thailand
BeeSat 5 – 8Berlin Experimental and Educational Satellites, communications
CubeSX-Sirius-HSERussian remote sensing CubeSat
DIY 1 / ArduiqubeArgentinian test for deorbiting mechanism
DMSat 1UAE multispectral satellite
ELSA-d TargetJapanese satellite demonstrating space debris removal technologies
FEESItalian educational and science research
GRBAlphaTechnology demonstrator for future CAMELOT constellation for gamma ray detection
Hiber 3Netherlands IoT satellite
Kepler 6 & 7Canadian IoT / M2M constellation made in Toronto by Kepler Communications
KMSLKorean scientific satellite from Chosun University
KSU-CubesatKing Saud University satellite for sending telemetry and images from space
LacunaSat 2bUK IoT satellite (part of a constellation)
NAJM-1Saudi Arabian pathfinder for Earth imaging and communication
NanoSatC-Br 2Brazilian satellite for science, technology including measuring the Earth’s magnetic field
Orbicraft-ZorkiyHigh resolution telescope
PixxelIndian Earth imaging satellite (eventually a constellation)
PumbaaKorean satellite for imaging the Sun’s corona
SMOG-1Hungarian educational and science research
STECCOItalian educational and science research, also attitude control testing
TimonKorean satellite for imaging the Sun’s corona
Vigoride “Strait of Magellan” (with SteamJet)Space tug developed by Momentus Space, mass ballast
WildTrackCube-SIMBAItalian satellite for monitoring behaviour of animals

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