By Xavier Luri Carrascoso, University of Barcelona
Working on a space mission is a bit like raising children: it takes years, patience and some suffering, but it is also very rewarding. For me parenthood and the work on a space mission started around 2001, when my wife, Isabel, gave birth to our daughter Ana and the European Space Agency (ESA) approved the Gaia mission.
Gaia’s main goal is to measure the distance to one billion stars (as I tell my kids, this is about two stars for each member of the European Union, so four stars are for them). Precisely measuring stellar distances is very difficult. It is done by measuring the stellar parallax, a very small angular displacement of the apparent position of a star in the sky caused by the movement of the Earth around the Sun (a perspective effect). The parallax is smaller for large distances and larger for short distances, which allows us to derive the distance to the star.