Selected Aug 1996; he had been Payload Specialist on STS-52 Mission LAGEOS-2 (responsible for the Space Visions System).
In December 1983, Dr. MacLean was one of six astronauts selected by the Canadian Space Agency (CSA). He began astronaut training in February 1984 and, in December 1985, was designated as the Canadian Payload Specialist to fly with the CANEX-2 set of Canadian experiments in space. His mission, STS-52, took place October 22 to November 1, 1992.
From 1988 to 1991, he was Astronaut Adviser to the Strategic Technologies in Automation & Robotics Program (STEAR).
From 1987 to 1993, he was Program Manager of the Advanced Space Vision System (SVS). In July 1992, NASA agreed to outfit the shuttle fleet with an operational version of the Orbiter Space Vision System (OSVS) which will give eyes to the Canadarm on board the space shuttle, and the Advanced Vision Unit (AVU) which will be used with the Mobile Servicing System (MSS). The MSS is Canada's contribution to the International Space Station. He was Program Manager for the OSVS until his interim assignment, in July 1993, to a collateral duty as Science Advisor for the International Space Station.
In 1993, he became an adjunct professor at the University of Toronto Institute for Aerospace Studies.
In April 1994, he was appointed Acting Director-General of the Canadian Astronaut Program. In July 1996 he was selected to attend NASA's Astronaut Candidate Training at Johnson Space Center, Houston, Texas.
Planned shuttle mission. Cancelled after Challenger disaster.
Deployed Lageos 2, CTA. Payloads: Laser Geodynamic Satellite (LAGEOS) II/ Italian Research Interim Stage (IRIS), Canadian Experiments (CANEX) 2, United States Micro-gravity Payload (USMP) 1, Attitude Sensor Pack-age (ASP), Tank Pressure Control Experiment (TPCE), Physiological Systems Experiment (PSE), Heat Pipe Performance (HPP) experiment, Commercial Protein Crystal Growth (CPCG), Shuttle Plume Impingement Experiment (SPIE), Commercial Materials ITA Experiment (CMIX), Crystals by Vapor Transport Experiment (CVTE).