Herschel and Planck

are on their way

BY KEITH COOPER

ASTRONOMY NOW

Posted: 14 May, 2009

The European Space Agency’s Herschel and Planck spacecraft have successfully launched atop an Ariane 5 rocket from the spaceport at Kourou, French Guiana. The launch took place at 2:12pm this Thursday afternoon.

Herschel and Planck ride into space on an Ariane 5 rocket. Image: ESA.

The long-awaited launch had its risks: by sending the two missions up in the same rocket, ESA were placing all their eggs in the same basket. Fortunately the launch was flawless, with the two spacecraft separating 26 minutes after blast off, propelled along trajectories that over two months will take them to the second Lagrangian point (L2) 1.5 million kilometres from Earth, on the opposite side of the planet to the Sun. The L2 point is a gravitationally stable orbit that will shield them from the Sun’s heat. This is crucial because both Herschel and Planck are required to be cooled to low temperatures to be able to operate at infrared and microwave wavelengths.

Herschel will be Europe’s answer to NASA’s Spitzer Space Telescope; an infrared observatory capable of peering into star-forming nebulae, proto-planetary discs and detecting cool objects such as red and brown dwarfs. It will measure the star-formation rate in galaxies during different epochs of the Universe, and ascertain the chemical composition of nebulae.

It is the largest space telescope ever launched, bigger even than the Hubble Space Telescope with a mirror 3.5 metres wide.

Planck, on the other hand, is charged with producing an all-sky map of the cosmic microwave background (CMB) radiation to unprecedented detail. The CMB is the very earliest radiation in the Universe that has imprinted on it the distribution of the seeds of denser matter that eventually grew into the galaxies we see today. By studying the CMB, Planck follows in the footsteps of NASA’s COBE and WMAP probes, and hopes to answer some fundamental questions about the beginning of our Universe, such as when the first stars formed and the nature of inflation.

“Planck is an incredibly exciting space mission that will soon be allowing us to travel back in time, nearly 14 billion years, towards the beginning of space and time as we know it,” says Professor George Efstathiou, a member of the Planck Science team.

“With Planck, we are pushing the boundaries of our knowledge to the very limits of what can be observed according to theory,” adds Professor David Southwood, Director of Science and Robotic Space Exploration at ESA.

“It is a tremendous technical challenge but helping to bring about a giant leap forward in our understanding of the origin and perhaps the fate of our Universe will be a tremendous reward too.”