Nasa has postponed a spacewalk aimed at fixing a torn solar wing on the International Space Station (ISS) until Friday at the earliest.
The delay will allow more time for engineers to study the problem, but could prohibit other necessary repairs.
The torn panel is part of an array attached to a girder that was moved on Tuesday from its temporary site on the platform to a new, permanent location.
Two spacewalking astronauts opened the wing to reveal a rip along the edge.
"This is a significant challenge for us to deal with, but we will deal with it," said Mike Suffredini, Nasa's ISS programme manager.
The ISS is being visited by space shuttle Discovery. Astronauts from the orbiter have already attached the new Harmony module to the station.
Harmony provides a passageway between three science laboratories:
- The existing US Destiny lab
- The soon-to-launch European Columbus module
- The future Japanese Kibo experimental units
There will be intense concern in Europe and Japan, however, over the latest developments.
The rip problem is compounded by the discovery last weekend of excessive wear in a motorised joint driving solar panels on the far side of the station. The gear is used to turn the wings to follow the Sun.
But Nasa has now limited the joint's use to prevent total failure, and this restricts the station's capacity to generate electricity. The Japanese and European space agencies will be eager to learn that the current difficulties will not hold up further expansion of the outpost.
The torn panel was almost completely unfurled when the rip was spotted. The astronauts beamed down photos of the torn and snagged section - about 80cm (2.5ft) in length - so Nasa engineers could analyse them.
"If we get the array down and we cut the snag and we figure out how to reinforce it, we'll redeploy the array," said Mr Suffredini.
"It's giving all the power we need. It doesn't have to look good, it's not about style points."
Nasa had already added a day to Discovery's mission so that a detailed inspection of the troublesome joint could be carried out. The spacewalk to fix the joint will now not take place until the repairs on the solar wing have been completed.
And a further planned spacewalk to carry out additional construction work on the space station will also now be postponed.
Discovery is due to undock from the space station on Monday and return to Earth on 7 November.