he first mission craft to photograph an asteroid was Galileo, in
• 1991.The photos taken by Galileo and those of more recent missions have completely rewritten the understanding of asteroids. These images first showed that many large asteroids are simply rubble piles and that asteroids could have their own moons. Without space missions, the science of asteroids would only be crawling slowly ahead rather than making the significant progress it is.
The minor planets have become important science; the numbers of missions reflect this interest. With at least 13 missions already completed or underway, the minor planets, taken together, have been visited more often than most of the major planets.
The primary scientific objective of ICE was to study the interaction between the solar wind and a cometary atmosphere. As planned, the spacecraft traversed the plasma tail of Comet Giacobini-Zinner on September 11, 1985, and made in situ measurements of particles, fields, and waves. It also transited between the Sun and Halley's comet in late March 1986, when other spacecraft (Giotto, Planet-A, MS-T5,Vega) were also in the vicinity of the comet on their early March comet rendezvous missions. ICE became the first spacecraft to directly investigate two comets.
These two missions to Venus and Halley's comet were launched by the Soviet Union. Two identical spacecraft, Vega 1 and Vega 2, were
Was this article helpful?