Minimize ISS: COLKa

ISS-COLKa (Columbus Ka-band antenna)

COLKa instrument and development    References

MDA (MacDonald Dettwiler and Associates Ltd.), a Maxar Technologies company, today announced that technology developed by its UK division in partnership with the UK Space Agency and the Canadian Space Agency has begun its journey to the ISS (International Space Station). The COLKa terminal of ESA (European Space Agency) was launched on 15 February 2020 aboard the Cygnus NG-13 Commercial Resupply Mission to the ISS. 1)

The MDA-built terminal will complement existing communication systems on board the ISS and utilize the EDRS (European Data Relay Satellite). Operating in the Ka-band, COLKa will enable dramatically higher communications bandwidth between ESA’s Columbus laboratory module on the ISS and ground stations and will provide ESA with an independent connection for faster delivery of scientific data and high-definition video. As a result, UK and European scientists and researchers will be able to see results of their ISS science experiments almost instantaneously.

COLKa was designed, developed and integrated by MDA Space and Robotics Limited in the UK, using funding provided by the UK Space Agency through the ESA Human Spaceflight program, the Canadian Space Agency through its cooperation agreement with the ESA, through the ESA ARTES program as well as through internal investment. MDA was supported on the project by Kongsberg Defence and Aerospace of Norway and Antwerp Space of Belgium, both of which made significant contributions to the development of key subsystems.

“This is the first major industrial contribution from the UK to the ISS, and it will revolutionize the ability of scientists in the UK and Europe to access the results of their experiments,” said Dr Graham Turnock, CEO of the UK Space Agency. “This is yet another example of the UK economy benefiting, through investment, jobs and new skills, from our continued collaboration with the European Space Agency.”

“The COLKa program has firmly established MDA in the UK as a leading provider of high-quality space equipment, positioning us for continued business growth and new jobs in both communications and space sensor markets,” said David Kenyon, Managing Director of MDA Space and Robotics Limited in the UK.

Developed with ARTES funding for some units, this fridge-sized telecom system was designed and built by UK (MDA) and Italian (Kayser Italia) companies as prime contractors, using products from Norway (Konsberg), Belgium (Antwerp Space), France (Thales Alenia Space), Canada (MDA) and Germany [ASP (Advanced Space Power Equipment GmbH) of Salem, Lake Constance].

The upgrade to the ESA Columbus laboratory will relay data from experiments on the Station back to Earth almost instantaneously. The device will send signals from the Station, which orbits at an altitude of 400 km above Earth, even further into space, where they will be picked up by EDRS satellites in geostationary orbit 36,000 km above the surface. 2)


Figure 1: Astronauts aboard the ISS plan to install a high-speed radio link to enable almost real-time connections with Earth. This image of the Columbus module was taken by ESA astronaut Luca Parmitano from outside the ISS on the second spacewalk to service the cosmic ray detecting Alpha Magnetic Spectrometer (AMS-02) on November 22, 2019 (image credit: ESA)

Launch: The Cygnus NG-13 spacecraft was launched on 15 February 2020 (20:21 GMT) on an Antares 230+ rocket from Virginia Space’s MARS (Mid-Atlantic Regional Spaceport) at NASA’s Wallops Flight Facility. This was Northrop Grumman’s 13th commercial resupply NASA-contracted mission. Cygnus was loaded with more the 3,630 kg of research, crew supplies and hardware. — The COLKa instrument was part of the equipment on this flight. 3)

Orbit: Near circular orbit, altitude of ~ 400 km, inclination = 51.6º, period of~92 minutes.

After the capture of Cygnus NG-13 at the ISS on February 18, 2020, the Northrop Grumman Cygnus spacecraft was bolted into place on the International Space Station’s Earth-facing port of the Unity module. 4)

COLKa instrument and development 

The COLKa Terminal will provide bi-directional communications between the Columbus laboratory and the EDRS satellite communication system. It is made up of a steerable antenna, RF signal processing assemblies (LNAs, frequency converters, etc.), digital signal processing assemblies (digital modulators and digital demodulators), Command and Data Handling assemblies (PIAU), DC power conditioning assemblies (PDU), micro-wave filters, waveguides inter-connects, co-axial cable inter-connects, high speed digital cable inter-connects as well as of survival heaters and DC harnesses. With the Forward Service Link , low-rate data is relayed from the EDRS System Ground Segment to the COLKa Terminal via the EDRS GEO satellite. The Return Service Link, also via the COLKa Terminal to the EDRS Ground segment via the EDRS GEO satellite, provides high-rate user data communications between the COLKa Terminal and the EDRS Ground Segment, such as video, sensor data, etc. 5)

The COLKa Terminal, along with the COLKa Platform, is identified as the COLKa Flight Unit (FU). The COLKa FU will be installed on a pre-defined, external section of the ISS Columbus Platform. The COLKa FU will be connected to Columbus laboratory interfaces via six cable harnesses. Delivered by the Embarkation Contractor (i.e. KI), the COLKa Platform includes the support panels and structure designed to withstand thermal and structural environments, interfacing with the COLKa Terminal equipment, the Columbus laboratory and the launch vehicle/temporary on-orbit stowage location. It also provides radiation shielding and protection against space debris and micrometeorites for the installed Terminal equipment.

Thermal design: The COLKa FU thermal control is based on heat dissipation through thermal radiative surfaces to limit higher temperatures in hot cases and the use of heaters to limit lower temperatures in the cold cases. Thermal insulating blankets, made of MLI, cover the non-radiative surfaces so to limit the heat rejection towards Columbus and the other ISS elements and so to contribute at limiting the COLKa FU temperature variations.

The outer layer of the MLI blanket will be made of a UV radiation and atomic oxygen resistant outer layer (Beta Cloth). The conductive heat flow, towards the Columbus through the Attachment feet and Attachment Bolts, is limited by using thermally insulating washers between the Attachment Bolts Stud and the Attachment Feet and between the Attachment Feet and the Columbus MDPS panels.


Figure 2: The COLKa antenna is being tested in the Hertz Test Chamber of ESA/ESTEC (image credit: ESA, M. Cowan) 6)

The COLKa system promises speeds of up to 50 Mbit/s in downlink and up to 2 Mbit/s in uplink. This will allow astronauts and researchers to benefit from a direct link with Europe at home broadband speeds – delivering a whole family’s worth of high data volume downlink and video streaming for science and communications.

The EDRS (European Data Relay Satellite) will transmit the data to a ground station at Harwell, UK, near ESA’s (European Center for Space Applications and Telecommunications), and from there the data will be transferred to the Columbus Control Center at DLR(Oberpfaffenhofen) and to user centers across Europe.

International teamwork

Kongsberg has been part of the team developing the terminal, through its Space & Surveillance division’s environment in Horten, Norway. The project has been headed by MDA Space and Robotics Limited, the UK division of MDA, the world leading Canadian space equipment manufacturer. 7)

Our Space Electronics team in Horten, formerly known as Norspace, has developed, manufactured and delivered frequency converters. They are critical parts of the COLKa Ka-band ISL (Inter-Satellite Link) terminal provided by MDA. The terminal itself offers the astronauts greater capacity and availability of broadband connection, as it is capable of speeds of up to 400 Mbit/s downlink and 50 Mbit/s uplink, says Ellen Tuset, Vice President Division Space in Kongsberg.


Figure 3: Kongsberg has delivered frequency converters to the COLKa terminal (image credit: Kongsberg)

Advanced ARGO modem of Antwerp Space for COLKa 8)

The advanced ARGO modem, developed by Antwerp Space, uses a high-performing encoding technology for the very first time in Europe. This modem will enable faster communication from the ISS to Earth via the new European Data Relay Satellite System (EDRS). The innovative Field Programmable Gate Array (FPGA)-based design allows an in-flight reconfiguration of the modem and gives a higher flexibility for different communication demands. The modem has been integrated within the MDA Corporation Ka-band Data Relay terminal COLKa, that will be mounted on the ESA Columbus module of the ISS in April.

ARGO is a bidirectional SDR (Software Defined Radio) modem, a transponder ensuring the the communication between the Columbus module of the ISS (International Space Station) and the Earth via EDRS (European Data Relay System). Because of its high computational power, ARGO is able to support the most demanding algorithms.


Figure 4: Photo of the ARGO modem (image credit: Antwerp Space)

Features of ARGO: 9)

The data relay modem has an RF interface in L-band. The modulator features downlink data rates up to 300 Mbit/s using O/QPSK modulation with a TX bandwidth of 405 MHz, while the demodulator features uplink data rates up to 2 Mbit/s using QPSK modulation with an RX bandwidth of 4 MHz. All CCSDS standard LDPC coding schemes and encapsulation schemes can be supported. The modem also supports high-gain antenna tracking functions.

The high level of FPGA integration is first an enabler for powerful and demanding algorithms: advanced coding layers (LDPC, Turbo-codes), spectral monitoring, authentication and encryption, as well as unified digital architectures such as putting all demodulator and modulator functions in one equipment. Also the SEU protection mechanisms are a lot more flexible in terms of cost to the customer. On top of those key advantages, the power-to-function ratio scales according to the level of integration, which can be used to fit demanding algorithms in challenging power envelopes.

To leverage this digital flexibility, and enable new applications without requiring a redesign in the digital hardware part of the system, it is organized so that only a redesign of the RF part is necessary. This RF section itself contributes to overall flexibility, being designed around subsampling data converters.

Another asset of this product is its in-flight reprogrammability as driven by market demand. Based on the fact that the SRAM-based FPGA is natively reprogrammable because of its need to be loaded at each boot time, Antwerp Space developed reliable upgrade procedures.

System architecture: The equipment is designed to be powered from a 28 V bus with a maximum power consumption of 35 W. For a cold redundant unit the mass budget is 3.6 kg, and the volume budget is 3.8 liter.

The equipment is divided into primary power supply conditioning done in the PSU board, RF signal processing functions and digital processing functions.

1) ”MDA-Developed Columbus Ka-Band Terminal (COLKa) Starts Journey to the International Space Station,” Business Wire, 15 February 2020, URL:

2) ”Space Station to forge ultra-fast connections,” ESA, 7 February 2020, URL:

3) ”NASA science and cargo head to Space Station,” Space Daily, 17 February 2020, URL:

4) Mark Garcia, ”Cygnus Cargo Craft Attached to Station for Three-Month Stay,” NASA Space Station, 18 February 2020, URL:

5) P. L. Ganga, V. Zolesi, F. Lorenzini, J. Persson, ”Columbus Ka-band Terminal thermal control - a compact design for varying conditions,” 46th ICES (International Conference on Environmental Systems), 10-14 July 2016, Vienna, Austria, URL:

6) ”Space antenna,” ESA Science & Exploration, 2 April 2019, URL:

7) ”Kongsberg contributing to broadband connection for the International Space Station,” 16 February 2020, URL:

8) ”Antwerp Space triples the download capacity of the International Space Station,” Antwerp Space Press Release, 15 February 2020, URL:

9) ”LEO Data Relay Modem,” ESA, 16 October 2019, URL:

The information compiled and edited in this article was provided by Herbert J. Kramer from his documentation of: ”Observation of the Earth and Its Environment: Survey of Missions and Sensors” (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. - Comments and corrections to this article are always welcome for further updates (

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