Vital stats

Herschel reflected in Planck mirror

Planck will offer vastly improved performance in measuring the Cosmic Microwave Background (CMB) radiation compared to balloon-borne and ground-based experiments and will exceed the performance of any previous space-based instruments of this kind.

The spacecraft revolves about its Sun-pointing axis once per minute to stabilise its attitude. Planck will use this stabilisation spin to scan the sky, observing at least 95% of it through two separate observation periods in a span of 15 months.

The Planck spacecraft
Dimensions 4.20 x 4.22 m (height x width)
Mass 1.95 tonnes at launch
Spacecraft Spin stabilised, 1 rpm
Telescope mirror 1.9 x 1.5 m primary reflector
Telescope mass 205 kg with focal plane unit
Lifetime A minimum of 15 months, limited by degradation of cooling system
Operational orbit Lissajous orbit at an average distance of 400 000 km from L2
Propulsion Hydrazine, 12 thrusters x 20 N each, 4 thrusters x 1 Newton each
Solar arrays Flat, fixed triple-junction Gallium-Arsenide cell panels on rear of spacecraft
Solar array area: 13m2
Batteries 39 Ah lithium ion batteries
Communication 3 x low gain antennae
1 x medium gain antenna
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