Robert Crippen traveled into space four times: as Pilot of STS-1 in April 1981, the first Space Shuttle mission; and as Commander of STS-7 in June 1983, STS-41-C in April 1984, and STS-41-G in October 1984.
Head entity: STS-41-G
Tail entity: Robert Crippen
Relation (head \u2192 tail): astronaut mission
Inverse relation (tail \u2192 head): crew member