Astronaut Bruce McCandless II, one of two 41B mission specialists, spacewalking a few metres from the Earthorbiting space shuttle Challenger. The shuttles cabin and open payload bay may be seen in the reflection from his goldtinted visor. This historic extravehicular activity was the first to make use of a nitrogenpropelled hand controlled device called the manned manoeuvring unit (MMU). The unit allows for much greater mobility than that afforded to previous spacewalkers who had to use restrictive tethers.
