In an attempt to salvage its position after weeks of negative headlines, National Aeronautics and Space Administration's (NASA) commercial crew programme manager has claimed that the astronauts aboard the Boeing Starliner are "not stranded" at the International Space Station.

After years of delays, Boeing's Starliner capsule carrying astronauts Butch Wilmore and Sunita Williams lifted off from Florida's Cape Canaveral Space Force Station on June 5, AFP reported.

Initially, the Starliner was set to return from ISS on June 14, but was pushed back for June 26. However, now the return is being further delayed due to multiple helium leaks.

When asked about the return date of the astronauts, the Nasa official said, "We don't have a targeted (landing) date today."

In a press conference on Friday, the manager said, "Butch and Suni are not stranded in space."

He added that the pair were "enjoying their time on the space station" and "our plan is to continue to return them on Starliner and return them home at the right time.".

According to reports, one helium leak was known prior to the launch; however, more leaks emerged during the 25-hour flight.

Separately, some of Starliner's thrusters that provide fine manoeuvring initially failed to kick in, delaying docking. Engineers are not sure why Starliner's computer "deselected" these thrusters, though they were able to restart all but one of them.

While talking about the negative comments, Boeing's Vice President and Programme Manager of its Commercial Crew Programme, Mark Nappi, said, "It is pretty painful to read the things that are out there. We've gotten a really good test flight that's been accomplished so far, and it's being viewed rather negatively."