Andrew Nowicki wrote:

PS. Imagine that hundreds of cheap telerobots have
been launched into cislunar space. High school volunteers
control them via Internet and use them to mine the
Moon and build orbital greenhouses...

Let us figure out how much it would cost.
One Dextre with the grapple arm costs $154 million
and weights about 2 tons. According to the calculator
(http://www1.jsc.nasa.gov/bu2/SVLCM.html) its cost
of manufacturing is about $41 million. The cost
of launching 2 ton spacecraft is $20 million.
According to another calculator
(http://www1.jsc.nasa.gov/bu2/MOCM.html) its
annual mission operations cost is about $9 million.

The total cost of building one hundred Dextre telerobots,
launching them into low Earth orbit, and using
them for one year is: $154M + (99 x ($41M + $9M)) =
$5,104 million = about $5 billion -- less than one
third of the annual NASA budget! Electrodynamic tethers
can provide cheap thrust in the low Earth orbit. There
will be additional cost of building a network of
terrestrial transponders -- perhaps $100 million.

I cannot think of a better way to spend $5 billion.