UPDATE: Europe's Galileo Launch Scrubbed for Today

UPDATE: Spaceflightnow.com reports at 5:26 am EDT October 20 that the launch has been scrubbed for today “after an anomaly during fueling of the Soyuz rocket’s third stage,” citing the French space agency CNES. ESA issued a press release at 5:36 am EDT confirming the launch has been scrubbed and saying that a new launch date will be announced later today.

At 6:34 am EDT tomorrow, Europe will launch two verification satellites for its Galileo navigation satellite system. The pair will be boosted into orbit by Russia’s Soyuz launch vehicle, the first such launch from the French launch site in Kourou, French Guiana.

Europe is heralding both events.

Galileo is a joint program between the European Union and the European Space Agency (ESA). Like the U.S. Global Positioning System (GPS), a total of 24 satellites are needed for the system to provide global three-dimensional (latitude, longitude, altitude) coverage, so this launch is only a first step. These two satellites are In-Orbit Validation (IOV) versions. Galileo is designed to be interoperable with GPS and Russia’s navigation satellite system, GLONASS.

A joint Russian-European agreement to launch Soyuz rockets from Kourou was signed in 2003. For Europe, Soyuz provides a medium-class launch vehicle to be paired with Europe’s large Ariane V and small Vega launch vehicles so a full range of launch services can be offered. The Vega rocket is expected to make its first flight very soon. Europe’s launches are conducted by the European company Arianespace, of which the French space agency is a 34 percent shareholder.

For Russia, Kourou offers a land-based launch site that is advantageous for placing satellites into equatorial and low inclination orbits. Kourou is located at 5 degrees North latitude, very close to the equator on the northern coast of South America. A low latitude launch site means that less fuel is needed to place a satellite into an equatorial orbit. That in turn means the satellite can weigh more than if it were launched an on equivalent rocket further North or South. By comparison, Russia’s most southern land-based launch facility, Baikonur (which it leases from Kazakhstan) is at 46 degrees North latitude. ESA notes that the Soyuz payload capability to geostationary transfer orbit from Kourou is almost twice that of a launch from Baikonur: 3 metric tons versus 1.7 metric tons.

The basic Soyuz rocket design dates back to the early 1960s; Russia has several versions in service today. The version being launched from Kourou is part of the Soyuz-2 series and uses a Fregat upper stage. It is designated VS01 by Arianespace. The failure of a slightly different version of the Soyuz (Soyuz U) in August that was taking a Progress cargo spacecraft to the International Space Station attracted a lot of headlines, but the Soyuz has quite a good track record over its multi-decade history.

Although launching from Kourou is particularly advantageous for equatorial launches, the Galileo satellites actually are headed for a fairly high inclination orbit, 54.7 degrees, but the mass of the two satellites does not require use of an Ariane V.

The launch will be webcast live