Before its telecommunication systems were switched off this afternoon, ESTCube-1 sent out its last-ever message. "Hello Earth! This is ESTCube-1. I have been working in space for a brighter future for 651 days. I will retire today and spend the next 20 years reading your Valentine's Day messages. Long live Estonia!" it signaled to earth in Morse code.

It was revealed today that one of the Valentine's Day messages it referred to included a marriage proposal. Unfortunately it's not known whether the proposal was accepted or not.

The 10 x 10 x 11.35 centimeter cube, weighing 1.048 kilograms, was sent into orbit on May 7, 2013. The main aim of Estonia's first ever satellite was to test solar sail technology developed by Finnish researcher Pekka Janhunen.

Project leader Mart Noorma said that the program met its aims - many young scientists and engineers have gained invaluable experience in space research. The project has yielded 29 bachelor's and 19 master's dissertations, 5 doctoral theses, 4 start-ups, and been the basis of 12 already published and 5 upcoming research articles, and 53 presentations.

"651 days, 10 communication sessions a day. So 6,500 sessions to conduct experiments and download data. That's how much we used it," Noorma told ETV's morning program "Terevisioon."

"ESTCube has been very resilient," he added, "but we are now approaching the time when its sun panels, damaged by cosmic radiation, are no longer able to produce enough electricity to power the satellite. So our student team figured why wait for the moment the satellite becomes unresponsive when we could just as well ceremonially retire it in the company of friends."

After the electronic systems are switched off, the satellite will remain in space for about 23 years, until it enters the earth's atmosphere and burns up.