This week, Space Shuttle Discovery docked with the International Space Station on it's 39th and final mission - one of the last by a NASA Space Shuttle before all the remaining vessels are decommissioned. Discovery flew its first mission in 1984 and is the eldest of the three craft still in service. When it is retired only Endeavour and Atlantis will remain active before they, too, are retired later this year when Atlantis flys the 135th mission in June.
The unspoken truth in the talk of the ending of the Space Shuttle programme is that, in addition to furthering our knowledge of Space and exploring our galactic surroundings, it has been tainted by tragedy and the cost of 14 lives. The Challenger disaster of January 28th 1986 (just over 25 years ago) and 2003's Columbia disaster both claimed 7 lives.
As the era of the Shuttle draws to an end, I've chosen this picture of the Challenger disaster as a reminder of the cost of human exploration of Space and the latest in the Iconic Images series: