Re: Would it be easier to push MIR into deep space than crash it into earth?

Good question and it would seem to make sense - except that MIR isn't
really in "outer space". And getting it into "deep space" would be very
difficult.

Currently, MIR's orbital altitude is about 310 kilometres above the earth. 
I say about because it is elliptical and varies from minute to minute. (If 
you would like to keep track, try 
http://www.hq.nasa.gov/osf/mir where 
one of the associated links takes you to a tracking program that tells you 
exactly where MIR is! This site is filled with lots of other interesting 
information about MIR.)

At an altitude of just 310 kilometres, the effort involved in lifting the
140 tonne station to anything approaching a geosynchronous orbit or a
stable parking orbit would be prodigious. We have been conditioned to think
that there is no gravity in outer space - after all, astronauts are 
weightless! But this isn't quite true. The reason that astronauts appear to 
weightless is that they are falling to earth at the same rate as their 
surroundings. Earth still has a strong gravitational attraction - it is
just nullified by both astronaut and vehicle falling at the same rate.

Earth's "gravity well" is steep and pushing a vehicle with over 140 tonnes 
of mass out of it would be difficult. Imagine just trying to pick up that 
sort of  mass off of the ground! Then, multiply the problem by the fact 
that you would have to move it several thousand kilometres upwards. Yes, 
gravity does decrease with increasing altitude but it would still take a 
tremendous amount of force. At 14 years old, it is unlikely that MIR could 
withstand the stresses involved in lifting it to new heights - and an 
uncontrolled break up would be disasterous. (Recall the attempts to bring 
down other satellites such as Skylab!)

Controlled re-entry is the method of choice for destruction and the only
real alternative for any satellite that is in low Earth orbit. Oh, yeah, 
and the new multi-billion dollar International Space Station is in low
Earth orbit which means one of these days it, too, will come crashing down.
Maybe this is the political reason behind crashing MIR - so that they can
figure out how to do it with something that is relatively small before
they have to crash the ISS! Just a thought....

Hope this answers your question.