Today marks the 40th anniversary of the launch of Prospero.  'And what's that?' I hear you ask.  Prospero is a 66 kg satellite, which is the only British-made spacecraft to be launched on a British-made launch vehicle.   Forty years ago at 04.09 UTC on 28 October 1971, Prospero was lobbed into orbit by a Black Arrow launcher from the Woomera Test Range in South Australia (see gallery).  And it still orbits today.
The occasion was a bitter-sweet event, as thereafter the UK launcher programme was cancelled and those working on the launcher project found themselves out of a job.  The story is something of a local one for me as well, as I reside in Southampton, and the first and second stages of the Black Arrow launcher were manufactured by Westland in East Cowes
on the Isle of Wight just a few miles south across the narrow strip of water called the Solent.  The launcher's rocket engines were also tested on top of the sea-facing cliffs just East of the Needles (striking chalk pinnacles rising from the Solent at the Western most tip of the Island).  A couple of photos I took of the rocket test site can also be seen in the gallery, showing the location of the rocket test stands as they are today.

ROSAT finally returned to Earth in the early hours of Sunday morning (23 October 2011), surprisingly without the usual media furore that accompany these events. Current information suggests it came down around 02.00 UTC, and the 'impact footprint' was mostly confined to the Indian Ocean region.  Well done to Hugh Lewis of University of Southampton, UK, for getting it 'right'!

Usually the re-entry of an orbiting spacecraft of significant mass is heralded by a flurry of reports in the media, sometimes prompting us hysterically to don hard hats and take cover!

After the hubbub caused by the recent re-entry of the UARS satellite over the Pacific Ocean, another spacecraft called ROSAT seems to have escaped much of the media’s attention so far.  ROSAT is a X-Ray telescope with a mass of around 2.4 tonnes, which is due to re-enter the Earth’s atmosphere in an uncontrolled manner in late October 2011. 
The telescope payload is around 1.6 tonnes, but it is unlikely to remain in one lump during the destructive process of descent through the atmosphere. However, items with masses in the region of 100’s of kg may reach the ground (or more likely the ocean).   A re-entry prediction done by a colleague at Southampton University UK, Dr Hugh Lewis, suggests that the re-entry may occur around the morning of 23 October 2011.  However, the exact time is difficult to predict at this distance away from the event.  I’m sure more refined estimates will be forth-coming when the media wake up to this
event.