Payload preparations for Ariane 5’s next launch are progressing at the Spaceport in French Guiana for a scheduled April 16th liftoff with a dual-passenger space science payload — this second Arianespace flight of 2009 will carry two European Space Agency spacecraft: Planck and Herschel, both of which are to explore the universe’s mysteries.

This Arianespace photo report details the activity with Planck, which is Europe's first mission to study relic radiation. Planck will measure the temperature variations across this microwave background with much better sensitivity, angular resolution and frequency range than any previous satellite – providing astronomers with an unprecedented view of the universe’s origin and the formation of galaxies.

The Planck spacecraft was produced by a Thales Alenia Space-led industrial team, and will weigh approximately 1.9 metric tons at launch. It consists of an octagonal service module that is topped with the telescope and associated instruments. The large upper baffle prevents stray light from the Sun and the Moon interfering with the detection of microwave radiation, and it helps dispose of heat generated by the scientific payload’s focal plane units. This head-on view details the Planck spacecraft’s mirror and its focal plane units for the scientific instrumentation, all of which are surrounded by the protective baffle. Planck will spin slowly in space, enabling the telescope to scan the sky as it focuses radiation into two highly sensitive detectors for the spacecraft’s low frequency and high frequency instruments.

Planck is raised to the horizontal position inside the Spaceport’s S1B clean room facility. This image clearly shows the spacecraft’s service module, which contains the computers and subsystems that manage Planck’s operation and processes raw data collected by the instrument detectors. Planck has a 4.2-meter diameter and will be installed as the lower passenger in Ariane 5’s dual payload “stack.”

With Planck in the background, spacecraft team members prepare the circular solar panel for installation on the base of the spacecraft’s service module. The solar panel will generate electrical power for the spacecraft, and will be permanently illuminated by sunlight during Planck’s mission — which has a nominal length of 21 months.









One of the solar panel segments is positioned under the Planck’s service module in this photo, which was taken by a wide-angle lens. After its deployment by Ariane 5, Planck will be injected into a Lissajous orbit around the second Lagrange point (L2) of the Sun-Earth system – situated at a distance of about 1.5 million km. from Earth.

(Source + images, courtesy of Arianespace)