But, unfortunately, Mars only allows minimum energy transfer orbits
only every so not too often so a blown landing opportunity also costs
you some years wait (which, of course,  is not at all what this
thread is about :-)

    Russell

-----Original Message-----
From: John Payson <supercat@CIRCAD.COM>


>|Seems the last Mars lander project did just that.


>If one builds two of the #1 units, the total cost is $2X (well under
>that of one design #2 unit) and one has the same probability of
>success as with the #2 design (there's a 1% chance both will fail).
>One also has the advantage, however, that if the first one happens
>to work one has a second one which can be used for further research.
>