The second paper appeared in PASP (2003), also
with father-son team Martin & Alex Harwit. You can access
this paper here. This goes through the arguments in the Science paper in more detail.
NASA has since announced that they will place a laser transmitter
(0.3m diameter, 5W mean power) around Mars
in 2009 beamed back to Earth. Following discussions with NASA in Sydney during the International Astronomical
Union (July 2003), the Anglo-Australian Observatory is to take an active part in this development, to be ratified at
meetings in Washington DC in early 2004. We have much to contribute to this project -- for more details, see our