This Sunday another Satellite is
due to come crashing down to earth. The German ROSAT
satellite finished its service in 1999 after nearly 7 years more
service than was originally planned. It was planed that the satellite that was
launched in 1990 would function for 18 months but was only shut down in 1999.
ROSAT was designed in the 1980's when the end of life of satellites was not
really considered so it was not built with its own propulsion system, like
modern satellites, which enables their re-entry conditions to be
controlled to ensure that they land in an uninhabited area of the globe.
The chance of this satellite causing harm to
anyone is higher then the previous uncontrolled decent at 1 in 2000. Some
confusion was noted in the run up to the UARS decent, this is not the chance
that you as an individual will get hurt, but that someone somewhere on the
planet will get hurt.
The satellite is predicted to fall somewhere
between 53° N and 53°S which unfortunately covers most of
the worlds landmasses. The exact location or timing cannot be
predicted at the moment due to changes in the radiation from the sun
causing the upper atmosphere to expand and contract changing the 'pull' of the
atmosphere on the satellite.
Increased solar
activity expands the atmosphere and increases the 'pull' advancing the descent
of ROSAT by a small margin each time.
Following
ROSAT_Reentry on twitter helps to get an understanding of when the satellite
will enventually fall, the current prediction is Space-Track #ROSAT Predicted Decay 2011-10-23 05:03 GMT ±
48 Hours as @ 2011-10-20 08:06 GMT
With a window of +/-
48h there is still a large margin of uncertainty. But it does look likely that
the satellite is no longer going to be visible from the UK, unless
the descent is at the right time so that some of the burn up in the
atmosphere is visible.
In other space
related news, look to the skys this evening as there is supposed to be
some Orionid activity. Meteors to you and I :D
