Europe’s New Eyes in Orbit

Ariane 5 lifts off with Herschel and Planck on board.
Credit: ESA

In the afternoon of Mary 14th, just under 40 minutes after liftoff, the European missions Herschel and Planck sent their first radio signals to Earth, confirming that they separated successfully from the launcher and were alive and well.

Herschel, the upper passenger, was the first to separate from the upper stage of the Ariane 5 at 15:38 central European summer time (CEST) at an altitude of about 1150 km over the east coast of Africa. About 1.5 minutes later, the Sylda support structure that enclosed Planck came off and separated. It was followed by Planck at 15:40 CEST at an altitude of about 1700 km slightly East of the east coast of Africa.

About 0.5 hours after launch, Herschel separates from the launcher upper stage (a couple of minutes before Planck).
Credit: ESA – D. Ducros, 2009

The satellites switched on their attitude control and telecommunications systems right after separation, to re-orient themselves and establish contact with Earth for the first time from space. The signals were received by ESA’s 35-m deep space antenna at New Norcia in Australia.

The mission control teams will continue to receive telemetry from Herschel via New Norcia, and for Planck via ESA’s antenna at Perth, also in Australia. Spacecraft Operations Engineers at the Mission Control Centre will use these data to assess the overall health of the satellites after launch.

Almost immediately after telemetry reception starts, engineers will determine the actual trajectory of each satellite so that it can be fine-tuned for planned trajectory correction manoeuvres.

Planck separated from the launcher a couple of minutes after Herschel.
Credits: ESA – D. Ducros

Herschel is a European Space Agency observatory that carries the largest, most powerful infrared telescope ever flown in space. Now in orbit, Herschel will begin its mission to study the origin and evolution of stars and galaxies. The mission’s primary objectives include observing asteroids and objects in our solar system’s Kuiper belt, studying the processes behind planet formation, and searching for the presence of water in remote parts of the Universe. Planck is designed to examine some of the most fundamental properties of the Universe, including the study of galaxies, including our own Milky Way.