Other space probes had their instruments examining Halley's Comet:
Pioneer 7 was launched on August 17, 1966. It was put into heliocentric orbit with a mean distance of 1.1 AU to study the solar magnetic field, the solar wind, and cosmic rays at widely separated points in solar orbit. On 20 March 1986, the spacecraft flew within 12.3 million kilometers of Halley's Comet and monitored the interaction between the cometary hydrogen tail and the solar wind.[1]
Pioneer Venus Orbiter in orbit of Venus, was positioned perfectly to take measurements of Halley's Comet during itsperihelion February 9, 1986. Its UV-spectrometer observed the water loss when Halley's Comet was difficult to observe from the Earth.[2]
TheSpace ShuttleChallenger, on its launch on January 28, 1986, was carryingSPARTAN-203 withthe mission to make observations of Halley's Comet.STS-51Lfailed to reach orbit, resulting in the total loss of crew and vehicle. That launch failure resulted in thecancellation of dozens of subsequent shuttle missions, including the next scheduled launch,STS-61-E, planned for March 6, 1986, with a payload including the ASTRO-1 observatory, which was intended to make astronomical observations of Halley's Comet.
TheInternational Comet Mission, consisting of a carrier NASA probe and a smaller European probe based on theISEE-2 design, with the intention that the American probe would release the European probe towards Halley for a close flyby, before going on to explore Comet10P/Tempel itself.[3] The NASA probe was cancelled November 1979.[4]
Any observations of Halley's Comet made by the crew ofSoyuz T-15, which made the first trip to theMirspace station and the last toSalyut 7 in March 1986, are unknown.