A Temporal Map in Geostationary Orbit: The Cover Etching on the EchoStar
  XVI Artifact
  Geostationary satellites are unique among orbital spacecraft in that they
experience no appreciable atmospheric drag. After concluding their respective
missions, geostationary spacecraft remain in orbit virtually in perpetuity. As
such, they represent some of human civilization's longest lasting artifacts.
  With this in mind, the EchoStar XVI satellite, to be launched in fall 2012,
will play host to a time capsule intended as a message for the deep future.
Inspired in part by the Pioneer Plaque and Voyager Golden Records, the EchoStar
XVI Artifact is a pair of gold-plated aluminum jackets housing a small silicon
disc containing one hundred photographs. The Cover Etching, the subject of this
paper, is etched onto one of the two jackets. It is a temporal map consisting
of a star chart, pulsar timings, and other information describing the epoch
from which EchoStar XVI came. The pulsar sample consists of 13 rapidly rotating
objects, 5 of which are especially stable, having spin periods < 10 ms and
extremely small spindown rates.
  In this paper, we discuss our approach to the time map etched onto the cover
and the scientific data shown on it; and we speculate on the uses that future
scientists may have for its data. The other portions of the EchoStar XVI
Artifact will be discussed elsewhere.
