IRT

IRT [NASA]

IRT canister [NASA]

The IRT (Integrated Rendezvous Target) was an inflatable rendezvous target, to be ejected in a canister from Space Shuttle mission STS-41B, then to be inflated with nitrogen.

IRT was scheduled as a pathfinder to the SolarMax Repair Mission (STS-41C), the rendezvous, capture and on-orbit repair of the SMM satellite. IRT was a 2 m diameter balloon that was to be deployed from a rack bolted to the forward end of the Space Shuttle Challenger's longeron on the port side of the payload bay. The target and its canister were ejected from the Challenger in a retrograde direction. One minute after ejection from the payload bay the canister was scheduled split in half and inflate automatically with nitrogen to a pressure of 0.3 psia. Built of one-mil thick aluminized Mylar, the IRT balloon was flat white in color except for one of the 24 gores painted infrared black. The balloon, inflation equipment and sintered tungsten ballast results in a total weight of 90.7 kg.

But the mechanism to open the canister was not activated, because the lanyards pulled loose from the orbiter instead of pulling out of the canister. The nitrogen inflation cartridge did fire as scheduled, and the balloon burst as it began to inflate inside its canister. The remaining pieces of the balloon provided enough of a target for three rendezvous instruments to provide data important in verifying their capabilities.