Dr Thomas was born in Adelaide, South Australia and graduated with First Class Honours in Mechanical Engineering in 1973 at theUniversity of Adelaide and received a PhD in Mechanical Engineering in 1978.

In May 1996 he took his first flight into space as the payload commander and mission specialist aboard the Space Shuttle Endeavour. Dr Thomas made three subsequent trips into space, including a space walk and an extended stay on the Russian MIR Space Station.