Second node ready to join European laser relay network

The EDRS C spacecraft undergoes testing at an Airbus Defense and Space facility. Credit: ESA – S. Corvaja

A German-built satellite designed to relay data between other orbiting spacecraft and ground stations using laser beams is set for launch in tandem with an Intelsat communications craft Tuesday from Kourou, French Guiana, aboard an Ariane 5 rocket.

The second node in the European Data Relay System, or EDRS, network is set for launch at 1930 GMT (3:30 p.m. EDT) Tuesday from the Guiana Space Center. The spacecraft, named EDRS C, will ride into orbit with the Intelsat 39 commercial communications satellite.

EDRS C will join the EDRS A node in geostationary orbit more than 22,000 miles (nearly 36,000 kilometers) over the equator. EDRS A is a hosted laser relay package on the commercial Eutelsat 9B communications satellite, which launched in 2016.

The EDRS network relays data and imagery from satellites in lower orbits, including the European Sentinel Earth observation fleet.

The EDRS system is similar to NASA’s Tracking and Data Relay Satellite, or TDRS, network, which began operations in the 1980s to close communications coverage gaps for spacecraft passing between ground stations. But unlike the U.S. system, the European data relay satellites carry laser communications links to enable super-fast transfers of information and imagery.

The EDRS network can transmit up to 40 terabytes of data per day, at a rate of 1.8 gigabits per second.

The European Commission’s Sentinel 1A, 1B, 2A and 2B Earth-imaging satellites are the anchor users of the European data relay system, which was developed in a public-private partnership between the European Space Agency and Airbus.

A new European laser terminal will launch to the International Space Station on a SpaceX resupply ship next year to be attached outside the station’s Columbus module. The arrival of the laser system will enable the EDRS network to connect with the space station, opening the door for faster data links for experiments hosted on the orbiting research complex.

Artist’s concept of the European Data Relay System. Credit: ESA

Airbus owns and operates the EDRS nodes in orbit, and sells access to the network — which it calls the “SpaceDataHighway” — on the commercial market. The EDRS control center is located in Ottobrunn, Germany.

“ESA is investing a chunk of money, and Airbus is putting some money on the table as well,” said Michael Witting, ESA’s EDRS project manager. “The logic behind it is ESA has covered most of the technical risks in the development phase, and Airbus has invested money, and they, in a sense, cover the market risk.”

Airbus’s four high-resolution Pléiades Neo optical reconnaissance satellites — the first two of which could launch in 2020 — will also link up with the EDRS network to transmit Earth imagery to the ground at high data rates.

The Eutelsat 9B satellite hosting the EDRS A payload is parked at 9 degrees east longitude in geostationary orbit, and EDRS C is heading for a position at 31 degrees east.

EDRS also hosts a commercial Ka-band communications package for the British company Avanti, which calls its payload Hylas 3.

Airbus announced earlier this year a cooperation agreement the SKY Perfect JSAT, a Japanese communications satellite operator, to co-finance design and development studies for a third EDRS node over the Asia-Pacific for launch before 2025.

The 7,023-pound (3,186-kilogram) EDRS C spacecraft was built by OHB in Bremen, Germany. The 14,550-pound (6.6-metric ton) Intelsat 39 communications satellite will join EDRS for the ride into space Tuesday.

An Ariane 5 rocket, operated by the French company Arianespace, will lift the two satellites into a highly elliptical, equatorial geostationary transfer orbit stretching 22,236 miles (35,786 kilometers) above Earth about a half-hour after liftoff.

The launch window for the Ariane 5 rocket extends until 2151 GMT (5:51 p.m. EDT) Tuesday.

Arianespace delayed the Ariane 5 mission from July 24 to clear the launcher of any faults related to the failure of a European Vega rocket July 10. The Vega rocket is a light-class launch vehicle — much smaller than the Ariane 5 — but the Avio, the Vega’s prime contractor in Italy, also supplies components for the Ariane 5’s two solid rocket boosters.

The Ariane 5 rocket arrived at the ELA-3 launch zone in French Guiana on Monday after rollout from the final assembly building. Credit: ESA/CNES/Arianespace – Photo Optique Video du CSG – L. Rouesne

During a launch readiness review Friday, Arianespace officials approved the mission for launch Tuesday. The Ariane 5 rolled out of its final assembly building Monday at the spaceport in South America for the 1.7-mile (2.7-kilometer) trip to the ELA-3 launch zone along dual rail tracks.

Countdown preps began early Tuesday, and Arianespace teams will oversee the loading of super-cold liquid hydrogen and liquid oxygen into the two-stage Ariane 5 in the final hours before liftoff.

The mission launching Tuesday will mark the 105th flight of an Ariane 5 rocket since 1996, and the third Ariane 5 flight this year.

The Ariane 5 launcher will deploy the Intelsat 39 spacecraft, which is riding in the upper position inside the rocket’s fairing, at Plus+29 minutes, 9 seconds. After jettisoning a Sylda dual-payload adapter, the Ariane 5’s upper stage will release the EDRS C satellite at Plus+33 minutes, 31 seconds.

The two payloads will use their own engines to maneuver from the Ariane 5’s elliptical drop-off orbit into a circular geostationary orbit, where their movement around Earth will match the rate of the planet’s rotation.

Built by Maxar Technologies, Intelsat 39 will park itself over the equator at 62 degrees east longitude to begin a 15-year mission providing C-band and Ku-band services across Asia, Africa, the Middle East and Europe.

Intelsat 39 will replace the aging Intelsat 902 satellite at the 62 degrees east orbital location. Intelsat 902 launched on top of an Ariane 4 rocket from French Guiana in 2001.

The Intelsat 39 satellite during fueling at the Guiana Space Center. Credit: ESA/CNES/Arianespace – Photo Optique Video du CSG – JM Guillon

Officials said Intelsat 39 will provide video and broadband services from its perch high above the equator. The new Intelsat spacecraft will also provide connectivity for airplanes and ships traveling in the Indian Ocean region.

Myanmar’s Ministry of Transport and Communications will be one of the main users of Intelsat 39’s capacity. Intelsat announced last year the the ministry signed a multi-year, multi-transponder agreement to use Intelsat 39 to provide broadband Internet services to government agencies, businesses and communities throughout Myanmar.

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