This year, the Hubble space telescope is celebrating its 30th anniversary in orbit. Launched on 24 April 1990 onboard the space shuttle Discovery, it was deployed into orbit a day later.
Since then, Hubble has been extraordinarily successful, making substantial scientific contributions to almost every branch of astronomy.
Thanks to its unique design, it has been repaired and upgraded five times by visiting astronauts and this has made it one of Nasa’s longest-lived and most valuable observatories. Only the retirement of the space shuttle in 2011 put a stop to future servicing missions.
Being above the atmosphere means Hubble has been able to take extremely sharp images and these often spectacular vistas have found their way into the public’s consciousness.
One of Hubble’s primary goals was to measure the speed at which the universe is expanding. It did this with such extraordinary precision that it revealed the expansion was accelerating.
To power the acceleration, cosmologists now believe that a mysterious energy field, known as dark energy, must be among the universe’s principal components.