Mareh 4, 1960

Dr. O. G. Villard
Stanford Electronics Labss

Dear Mike +
Some comaents on Needles,

I don't disagree at all with the conclusions of the comaittee though
I would have liked to have seen some very explicit statement on the fate
after reentry of partigles fx of some indicated compositions. The one point
I would add ta this-~ if there are ‘internakional' implications, some of
our*friends*may be looking for trouble, and we ought to foresee some of their
strategy. This was the main reason I suggested including some characteristic
‘marker’ substance in the needles ~~ not that I expect we will ever be able
to find one again in the terrestrial haystack, but to be able to ve able to
rule out any claims to that effect if they are made, ven in domestic law,
you might find suits from some oranks could be forestalled more readily if
there were some very explicit advance provision for identifying a needle, even
after some deformation.

This would cost almost nothing; I had in mind adding some isotope with
unique mass number to whatever material you used,

~hS~there~any~Way .
Wil individual needles incandesce visibly on reentry? If so, would there

be some point te using an element (Na, K, Sr?) that would make this more charac-
teristic; or would this be insignificant part of the emission?

Yours,

Joshua Lederberg