A Temporal Map in Geostationary Orbit: The Cover Etching on the EchoStar XVI Artifact

TL;DR

This paper describes the design and scientific content of a temporal map etched onto the cover of the EchoStar XVI artifact, a long-lasting geostationary satellite serving as a message to future civilizations.

Contribution

It introduces the concept and details of the temporal map etched on the artifact, including star charts and pulsar timings, as a novel form of interstellar message.

Findings

The temporal map includes star charts and pulsar data.

The pulsar sample contains 13 objects, 5 with highly stable spin periods.

The paper discusses potential future uses of the data by scientists.

Abstract

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.