Citation
Abstract
Approximately one-dozen X-ray pulsars are presently known which emit strong stable pulses with periods of 0.7 to ~1000 s. By comparing the arrival times of these pulses at a spacecraft and at the Earth (via an Earth-orbiting satellite), a three-dimensional position of the spacecraft can be determined. One day of data from a small (~0.1 m?) on-board X-ray detector yields a three-dimensional position accurate to ~150 km. This accuracy is independent of spacecraft distance from the Earth. Present techniques for determining the two spacecraft coordinates other than range measure angles and thus degrade with increasing spacecraft range. Thus navigation using X-ray pulsars will always be superior to present techniques in measuring these two coordinates for sufficiently distant spacecraft. At present, the break-even point occurs near the orbit of Jupiter. The Crab pulsar can also be used to obtain one transverse coordinate with an accuracy of ~20 km.
Details
- Volume
- 42-63
- Published
- June 15, 1981
- Pages
- 22–25
- File Size
- 226.0 KB