A newly arrived Russian science lab briefly knocked the International Space Station out of position.
For 47 minutes, the space station lost control of its orientation when the Russian lab accidentally fired its thrusters after docking, pushing the complex from its normal configuration.
The station’s positioning is key for getting power from solar panels and communications.
Communications with ground controllers also blipped out twice for a few minutes.
Flight controllers regained control using thrusters on other Russian components at the station to right the ship and it is now stable and safe, Nasa said.
“We haven’t noticed any damage,” space station programme manager Joel Montalbano said in a late afternoon press conference.
“There was no immediate danger at any time to the crew.”
Mr Montalbano said the crew did not really feel any movement or any shaking.
The complex was never spinning, Nasa spokesman Bob Jacobs said.
Nasa associate administrator for human exploration and operations Kathy Lueders called it “a pretty exciting hour”.
The incident caused Nasa to postpone a repeat test flight for Boeing’s crew capsule that had been set for Friday afternoon from Florida.
It will be Boeing’s second attempt to reach the station before putting astronauts on board.
Russia’s long-delayed 22-ton (20-metric-ton) lab called Nauka arrived earlier on Thursday, eight days after it was launched from the Russian space launch facility in Baikonur, Kazakhstan.
The automated docking followed after a long journey and a series of manoeuvres.
The launch of Nauka, which is intended to provide more room for scientific experiments and space for the crew, had been repeatedly delayed because of technical problems.
It was initially scheduled to go up in 2007.
In 2013, experts found contamination in its fuel system, resulting in a long and costly replacement.
Other Nauka systems also underwent modernisation or repairs.
Nauka became the first new compartment for the Russian segment of the station since 2010.
On Monday, one of the older Russian units, the Pirs spacewalking compartment, undocked from the space station to free up room for the new lab.
Nauka will require many manoeuvres, including up to 11 spacewalks beginning in early September, to prepare it for operation.
The space station is currently operated by Nasa astronauts Mark Vande Hei, Shane Kimbrough and Megan McArthur; Oleg Novitsky and Pyotr Dubrov of Russia’s Roscosmos space corporation; Japan Aerospace Exploration Agency astronaut Akihiko Hoshide; and European Space Agency astronaut Thomas Pesquet.
In 1998, Russia launched the station’s first compartment, Zarya, which was followed in 2000 by another big module, Zvezda, and three smaller modules in the following years.
The last of them, Rassvet, arrived at the station in 2010.
Russian space officials downplayed the incident, with Dmitry Rogozin, head of Roscosmos, tweeting: “All in order at the ISS.
“The crew is resting, which is what I advise you to do as well.”