On Jan 25, 3:54*pm, wrote:
"Although the U.S. won’t be able to meet the
congressionally mandated goal of locating and
cataloging most near-Earth objects 140 meters
across or larger by 2020, it could come close
to that deadline if a new space-based
observatory is dedicated to the task in concert
with a suitable ground-based telescope,
according to a National Academies panel.

The panel’s final report, released Jan. 22,
asserts that the combination of space and
ground-based observation is “the best approach,”
and could complete the survey as early as 2022
if funds are appropriated quickly."

See:

http://www.aviationweek.com/aw/gener...s/asd/2010/01/....

Yes, by far the most worthwhile bang for the buck. However, according
to some, we may have only until December 2012, and that's a decade
short of 2022.

~ BG