General Relativity Time Delay Experiment
摘要
In February of 1997, the Near Earth Asteroid Rendezvous (NEAR) spacecraft passed behind the sun and continued on to encounter the asteroid Mathilde and rendezvous with the asteroid Eros. As the spacecraft passed behind the sun, the path of the two-way radio signal from the Deep Space Network (DSN) comes close to the sun and vanishes as the spacecraft is eclipsed by the sun. The signal from the DSN to the spacecraft and back to Earth is delayed from what it would be if the sun was not present due to solar plasma and the effect of general relativity. It is not unusual for interplanetary spacecraft to be eclipsed by the sun because planets, comets, and asteroids tend to have orbits near the ecliptic plane. However, the NEAR geometry was particularly favorable and provided an excellent opportunity to measure the general relativity delay.