The coming week is going to be crucial for space astronomy.
On Monday the shuttle Atlantis is due to blast off from Cape Canaveral with seven astronauts, on Nasa’s fifth and last mission to service the 19-year-old Hubble Space Telescope.
Then on Thursday it will be the European Space Agency‘s turn. An unmanned Ariane 5 rocket will send two new observatories costing a total of €1.9bn, Herschel and Planck, into space.
Hubble is the most famous and successful telescope of modern times. It has sent back to Earth a stunning series of images of distant stars and galaxies, which have enabled astronomers to calculate the age of our universe (13.7bn years), estimate the speed at which it is flying apart and examine planets around other stars, among many other things.
The final servicing mission, costing $1bn, will replace some instruments on Hubble, mend others and replace batteries and gyros – extending its working life for at least five years. It is the most difficult mission undertaken by the shuttle, because it goes higher into orbit than routine flights to the International Space Station and involves more intricate space walks.
While Hubble looks at objects in the visible regions of the spectrum, Herschel and Planck operate at much longer wavelengths, which are not detectable by our eyes.
Although the pair are sharing a ride on Ariane 5, they are independent observatories.
Herschel will observe at a region of the spectrum, known as far infrared and submillimeter, that has until now been neglected by astronomers. This should enable it to see through dust and gas, which obscure observations at other wavelengths, to see stars and galaxies in their early stages of development.
Planck is designed to examine in greater detail than any previous instrument the “cosmic microwave background” radiation, left over from the Big Bang 13.7bn years ago. Cosmologists hope it will show them how an initial period of unbelievably rapid expansion laid down the patterns of stars and galaxies we see today – and help to explain mysteries such as dark matter and dark energy.