KOUROU, French Guiana — A Europeanized Russian Soyuz rocket on March 27 successfully delivered two European Galileo navigation satellites into orbit, stabilizing a program that was knocked off balance in August when the same vehicle put the two previous Galileo spacecraft into a badly off-target orbit.
Operating from Europe’s Guiana Space Center spaceport here on the northeast coast of South America, the four-stage Soyuz-Fregat rocket released the 7th and 8th Galileo satellites into a circular orbit of about 23,522 kilometers in altitude.
The satellites will use their own thrusters to maneuver to an operating orbit 300 kilometers lower. Galileo is intended as a 24-satellite operating constellation with six in-orbit spares.
At least one, and maybe two, more Soyuz Galileo launches are scheduled for this year, the first in September. Starting in 2016, Europe’s heavy-lift Ariane 5 rocket will share Soyuz duties for Galileo launches, with each Ariane 5 carrying four 715-kilogram Galileo satellites.
Future Galileo launches will carry added insurance, European Space Agency officials said. Those to date have been insured only against a launch vehicle failure. For future launches, the satellites themselves also will be insured.
In its short history, the Galileo program has seen launch vehicle and satellite problems. The four Galileo in-orbit validation satellites launched on Soyuz rockets in 2011 and 2012 have a defective antenna that has taken one of them out of service and threatens the other three.
Then the August launch anomaly, traced to a design flaw in the Fregat upper stage, put two satellites into a useless orbit from which they have been brought back into a position that will allow them to integrate into the operational constellation.
It is rare, but not unprecedented, for governments to purchase insurance coverage for their satellites and launches.
On this latest launch, the Fregat stage released the two Galileo satellites nearly three hours and 48 minutes after liftoff after two ignitions separated by a long ballistic phase. Even then, the Arianespace launch consortium – adopting an extreme prudence after the premature celebration during the August launch – waited well over an hour after separation before confirming that the orbital altitude and inclination was on target.
The target orbital injection parameters: A circular orbit at 23,522 kilometers, with an inclination of 55.04 degrees.
The actual results: A circular orbit at 23,600 kilometers, with an orbital inclination of 56 degrees.