From: palmer@cco.caltech.edu (David M. Palmer)
Subject: Re: Gamma Ray Bursters. positional stuff.
Organization: California Institute of Technology, Pasadena
Lines: 38
NNTP-Posting-Host: alumni.caltech.edu

henry@zoo.toronto.edu (Henry Spencer) writes:

>In article <1993Apr29.010847.1@vax1.mankato.msus.edu> belgarath@vax1.mankato.msus.edu writes:
>>        Actually, my advisor, another classmate of mine, and me were talking
>>the other day about putting just one detector on one of the Pluto satellites.
>>THen we realized that the satellite alone is only carrying something like 200
>>pounds of eq.  Well, a BATSE detector needs lead shielding to protect it,
>>and 1 alone weighs about 200 pounds itself.

>Actually, the situation is even worse than that.  The *total mass* of the
>Pluto Fast Flyby spacecraft is only 250ish pounds, and most of that is
>support equipment like power and communications.  The mass available for
>instruments is maybe 10% of that.  I don't think a BATSE will fit...

From the Pluto Fast Flyby Instrument definition research anouncemnet,
the instrument payload constraints are:
    Mass allocation -  7 kilograms (15.4 lbs)
    Power allocation - 6 watts
    Required instruments:
	Visible imaging system (1024x1024 CCD, 750 mm fl, f/10 optics)
	IR mapping spectrometer (256x256 HgCdTe array, 0.3% energy resolution)
	UV spectrometer (55-200 nm, 0.5 nm resolution)
	Radio science (ultrastable oscilator incorporated in telecom system)
		ultrastable means 10^-14.

This doesn't leave much room for payloads which are totally unrelated
to the  mission of the spacecraft.  In addition, the power will come
from a radioisotope thermal generator, and the whole space craft will
be about 2 feet in diameter, with no booms, which means there will be
strong gamma-lines from Pu-239 and associated schmutz in the
background, which tends to reduce sensitivity somewhat.

It would still be nice, and our group here at Goddard is looking
in to it.

-- 
		David M. Palmer		palmer@alumni.caltech.edu
					palmer@tgrs.gsfc.nasa.gov
