(CNN) -- NASA is monitoring debris in space moving in the vicinity of the international space station and the Shuttle Discovery docked with it, officials said late Wednesday.
The debris, measuring "multiple meters" in size, is from a European Ariane series rocket launched in 2006, NASA said.
By 10:06 a.m. ET Friday, the debris will be moving within 3 km (1.8 miles) of the space station, the agency said.
Officials will decide by Thursday morning whether astronauts will have to fire thrusters on the Discovery to nudge the shuttle and the space station out of the way, NASA said.
CNN's John Zarrella contributed to this report.