It was called an Eagle and there were two versions - one with radoiactive canister that lowered on string and another one that had a cool pod whcih separated from the centre of the spaceship. Very cool. I was actually saving up for a pair of Dr Martin boots with steel toecaps and 21 laceholes but saw this and bought it instead.

They were made by Dinky Toys, not Corgi, and for the price they were pretty impressive. When I was a kid I had an Eagle Transporter, which had the metal parts painted in metallic green with red tanks, chromed plastic nozzles, and a white metal transporter pod. I also had an Eagle Freighter, which had white metal parts, chromed tanks, red plastic nozzles, and a red metal freighter pod with four yellow plastic cannisters like Dave described. Dinky went through a few different color combinations over the run of the product, but even as a kid I never understood why they weren't all colored like they were in the show.