Svalbard Satellite Station (Norwegian: Svalbard satellittstasjon) or SvalSat is a satellite ground station located on Platåberget near Longyearbyen in Svalbard, Norway. Opened in 1997, it is operated by Kongsberg Satellite Services (KSAT), a joint venture between Kongsberg Defence & Aerospace and the Norwegian Space Centre (NSC). SvalSat and KSAT's Troll Satellite Station (TrollSat) in Antarctica are the only ground stations that can see a low altitude polar orbiting satellite (e.g., in Sun-synchronous orbit) on every revolution as the Earth rotates. As of 2021, the facility consists of 100 multi-mission and customer-dedicated antennas which operate in the C, L, S, X and K bands. The station provides ground services to more satellites than any other facility in the world.

Customers with their own installations include the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), the National Aeronautics and Space Administration (NASA), the European Space Agency (ESA) and the National Oceanic and Atmospheric Administration (NOAA). The station also reads and distributes data from the Japanese Hinode solar research satellite. The facility has seen a large increase in smaller customers after 2004, when the Svalbard Undersea Cable System started providing a fiber Internet connection. Concessions for downloading are only issued to civilian satellites, yet some data has been indirectly used by armed forces. There is a disagreement as to whether this constitutes a breach of the Svalbard Treaty.^{[citation needed]}

The European Space Research Organization (ESRO) established Kongsfjord Telemetry Station in Ny-Ålesund as one of its four initial European Space Tracking Network stations. The facility remained in use from 1967 to 1974, but was closed as it was not suitable for ESRO's second generation of satellites. During the planning of the station, Longyearbyen had been proposed as a location, and it was largely political concerns by Norwegian authorities to create permanent activity in Ny-Ålesund which lead ESRO to accept the location.

In the 1990s, NSC operated Tromsø Satellite Station (TSS), which was used as a ground station for a limited number of satellites. After Rolf Skår was appointed director of NSC, plans were launched to try to win the ground station contract for NASA's planned Earth Observing System (EOS). NASA was considering locating the ground station in Greenland, at McMurdo Station in Antarctica or at Esrange in Sweden. Skår invited a NASA delegation to visit Svalbard, and from 1996 NSC and NASA started negotiating a contract to establish a ground station at Longyearbyen.

Svalbard was chosen because of its high latitude from which every polar-orbiting satellite above 500 kilometers (310 mi) can be seen on every revolution as the earth rotates within its orbital plane. For the EOS program, Svalbard was supplemented by Poker Flat Research Range in Fairbanks, Alaska. Construction of the road up to Platåberget started in 1996 and a relay station was built to send the data to Isfjord Radio before being sent onwards to a geostationary satellite. The first installation was an 11-meter (36 ft) parabolic antenna with S and X band capability.

The first satellite to use SvalSat was Landsat 7, which was launched on 15 April 1999. It was followed up by three other EOS satellites: Terra, Aqua and QuikSCAT. To ensure a sustainable financing of operations, NSC started negotiating with other potential customers. However, the project was rejected by the Indian Space Research Organisation. Instead, a cooperation was made with Kongsberg Aerospace and Defence and Lockheed Martin, who built the second antenna as a joint venture. In 2001, a German research group applied for permission to establish a ground station in Ny-Ålesund. NSC feared that the competition could undermine the financial capabilities of SvalSat. However, no facility in Ny-Ålesund was built.

In 2002, ownership and operations of the facility were consolidated and taken over by the newly created Kongsberg Satellite Services. Lockheed Martin was no longer interested in owning a share of the facility, and sold their shares. NSC and Kongsberg merged their interests in the new company, which also took over TSS. By 2004, six antennas, between 9 and 13 meters (30 and 43 ft) in diameter, had been installed.

Northrop Grumman and Raytheon decided in 2002 to locate its ground station for National Polar-orbiting Operational Environmental Satellite System, the successor of EOS, to Helsinki, Finland, instead of Svalbard. The reason was lack of optical fiber cable connection to the archipelago. NSC took initiative to build such a cable in July 2002 and gained interest from NASA, NOAA and Telenor. The cable was financed by the satellite operators paying the same fee for the transmission of data as they would have to pay for a satellite connection until the cable was paid for. A 40 million United States dollar contract was signed with Tyco International for two cables between Harstad on the mainland and Longyearbyen. Construction started in June 2003 and was completed in January 2004.