A malfunction on a docked Russian spacecraft caused the International Space Station to shift from its normal orbital orientation, the Russian space agency Roscosmos said on Tuesday.
NASA confirmed that the engines of Soyuz TMA-15M – one of two Soyuz spacecraft currently docked at the ISS – unexpectedly fired at 10:27am Central time on Tuesday, pushing the station somewhat out of its expected position.
The unplanned incident occurred during testing of a radio system that controls the docking procedure, the Associated Press reports.
"Actions were immediately taken to reorient the ISS," NASA said in a statement. "There was no threat to the crew or the station itself, and the issue will have no impact to a nominal return to Earth of the Soyuz TMA-15M on Thursday."
When the TMA-15M does reenter the atmosphere, it will be carrying three of the six crew members currently aboard the ISS, including the European Space Agency's Samantha Cristoforetti, Russia's Anton Shkaplerov, and US astronaut Terry Virts.
All three were originally expected to return to Earth on May 14, but those plans were put on hold following the catastrophic loss of the Progress M-27M supply pod, which spun out of control and eventually blew up during a resupply mission to the ISS on April 28.
That delay means Cristoforetti will have spent 200 days in space by the time she touches down on terra firma, breaking American Sunita Williams' previous record for a woman on a single space voyage by five days.
Roscosmos specialists are still trying to determine the reason for the accidental engine ignition and NASA says it will provide more information once it knows more.
A slight change in orbit isn't really a crisis for the ISS, however, which has undergone such adjustments intentionally in the past. The last time was on May 18, when Roscosmos fired the engines of the TMV Progress M-26M for 1,922 seconds, increasing the ISS's orbital height by 2.8km (1.74 miles). ®