 path edu!da-new harvard edu!noc net!uunet!digex com!digex net!not-for-mail from prb access digex net pat newsgroup sci space subject re combo propuls system!? date 2 mai 1993 15 08 02 -0400 organ express access onlin commun usa line 10 messag-id 1s166i 803 access digex net refer 1993mai1 043916 1 aurora alaska nntp-post-host access digex net how difficult solar sail mission mercuri? not 23?km delta eat solar sail handl adiscoveri bu drop mercuri orbit good rocket form polar orbit? pat 