WASHINGTON (Reuters) - RTX Corp ( RTX ) subsidiary Collins Aerospace is in talks with NASA to back out of its contract to build new spacesuits for astronauts on the International Space Station, setting back the agency's bid to modernize its decades-old spacesuits, according to two people familiar with the discussions.

The contract was part of $3.5 billion awarded to both Collins and Axiom Space by NASA in 2022. A breakdown of the contract was not provided at that time.

RTX and NASA did not immediately respond to requests for comment.

Spacesuits, essentially human-shaped spacecraft, have been a persistent development challenge for NASA, whose astronauts 250 miles above Earth on the ISS currently rely on spacesuits developed some four decades ago with only a few refurbishments and updates since.

NASA has had two rare cancellations of astronaut spacewalks this month because of the spacesuits. The agency cited a "spacesuit discomfort issue" that prompted the cancellation of two astronauts' planned spacewalk on June 13.

The second attempt at the spacewalk, on Monday, was also canceled because of a water leak.

Collins has been seen as a leader in spacesuit development but has struggled on its current contract, the two people said.