Vega Rocket Grounded by High Winds over Kourou

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KOUROU, French Guiana — Teams preparing for the second flight of Europe’s Vega rocket were settling in for what could be a launch delay of several days due to unacceptably strong easterly winds over the Guiana Space Center launch site.

The Arianespace launch consortium of Evry, France, on May 6 said a fresh launch attempt would be made the evening of May 6.

In a sign of how long the wait may be, senior European Space Agency (ESA) and French space agency, CNES, managers returned to Paris Sunday. Flight time between Paris and the French Guiana spaceport, on South America’s northeast coast, is between eight and nine hours.

The May 3 launch countdown was stopped just 30 minutes before ignition after the last of several weather balloons sent up to verify atmospheric conditions returned data showing 50-kilometer-per-hour winds at 20 kilometers in altitude, according to Guiana Space Center Director Bernard Chemoul of CNES.

The problem is not the ability of the rocket to travel through such weather, but rather the safety risk to the local population here in the event the vehicle had to be destroyed because of an unrelated flight malfunction.

The four-stage Vega rocket reaches Max Q – the point of maximum dynamic stress on its structure – some 50 seconds after liftoff, when it has reached an altitude of about 12 kilometers, according to ESA program managers. At that point the vehicle is traveling at a speed of some 2,100 kilometers per hour.

As is the case for most planned Vega missions, the launch is scheduled to carry science and Earth observation satellites into polar orbit, meaning a northward trajectory as opposed to the eastward launch trajectory used for telecommunications satellites heading to geostationary orbit over the equator. Should the rocket malfunction, it would need to be destroyed, an act that would create multiple pieces of debris. With a strong easterly wind, some of the debris would be blown west, raising the risk of its falling on populated areas here.

One of the advantages of the European spaceport, besides its being near the equator and on French territory, is that vehicles can be launched to the north, the northeast and the east, all over Atlantic Ocean without overflying populated areas.

CNES President Jean-Yves Le Gall said it is not uncommon at this time of year for high-level winds to remain over the launch base for several days without interruption.

For its second flight, which is the first of a planned five Vega missions to orbit European Space Agency science and Earth observation payloads, the rocket will be carrying the 140-kilogram Proba-V Earth observation and technology-demonstration satellite. Also on board will be Vietnam’s 115-kilogram VNREDSat-1 optical Earth observation satellite, built by Astrium Satellites of Europe under commercial contract to the Vietnam Academy of Science and Technology; and Estonia’s first satellite, ESTCube-1, a 1.3-kilogram cubesat built in part by university students under the authority of the Estonian Space Office.

All three satellites will be dropped off into sun-synchronous orbit, inclined at 98 degrees relative to the equator, at altitudes of between 600 and 820 kilometers.