ALMA: reaching astronomical heights!
A new view of space
A design challenge
As lead company in the European AEM consortium, Thales Alenia Space acted as prime contractor for the 25 European antennas for the ALMA project. It took 10 years to build the subassemblies in Europe, transport them to Chile, install them at the site in the Atacama desert, 5,000 meters above sea level, then calibrate them and demonstrate compliance with technical specifications.
Achieving the requisite levels of performance for these huge antennas — including a reflector surface engineered to be accurate to 11 microns, or one-fifth of the thickness of a human hair, combined with extreme pointing precision on the furthest objects — called for an unprecedented feat of engineering. All these machines need to point at exactly the same location in space at exactly the same time, despite the extreme conditions of the high-altitude desert environment. The main challenges were the effect of Earth’s gravity, exposure to wind gusts and temperature fluctuations of almost 40°C in the space of just a few hours. Even the slightest design weakness could cause pointing accuracy to be compromised. In operation for several years now, the ALMA antennas have not once failed in their task!
On the top of the world
Mission accomplished!
ALMA image of a ring around the bright star Fomalhaut
In September 2013, after successful acceptance tests, Thales Alenia Space handed ownership of the 25th and final European antenna to its customer ESO. In the last few weeks, with the warranty period now at an end, ESO and the AEM consortium signed a close-out agreement, marking the effective completion of the 10-year-plus contract. The antennas are working perfectly, with their remarkable levels of performance recognized by users and attested by ESO. Hardly a week goes by without the ALMA Observatory announcing new scientific findings, some complete with spectacular images of space – just a click away on the ESO website!
Photos copyrights: ESO