A brief but rare ‘tug of war’ between two thrusters on the International Space Station
The International Space Station unexpectedly shifted in orbit on Thursday when thrusters on a newly docked Russian module began firing uncontrollably. The thrusters reoriented the football-field-sized laboratory’s position by as much as 45 degrees, NASA said. The station is back under control, a NASA spokesperson said, and its seven-person crew of astronauts, including three US astronauts, are safe, according to the agency.
The erroneous thruster firings from Russia’s Nauka module, a new 23-ton multipurpose laboratory, began a few hours after it docked to the ISS at 12:25PM ET, NASA spokesman Rob Navias said. Mission control at NASA’s astronaut headquarters in Houston first noticed the space station deviate from its normal position a few minutes later, triggering an automatic alert to the astronauts on board. By 12:42PM ET, the space station had lost control of its positioning, NASA’s ISS manager Joel Montalbano said during a press conference on Thursday.
“WE’RE IN A LITTLE BIT OF A TUG OF WAR BETWEEN THRUSTERS FIRING…”
The station, an ornate science laboratory with 16 pressurized living and cargo modules, was pitching off track by about 1.5 degrees each minute, NASA officials said. Thrusters on another side of the space station, from Russia’s Zvezda service module, fired up to counter the force from Nauka in what NASA’s mission control communicator described as a “tug of war.”
“Just to update you guys,” mission control communicator Drew Morgan told US astronauts from Houston, “right now we’re in a little bit of a tug of war between thrusters firing from both the [service module] and [Nauka]. We are sorting through the best course of action right now.”
Nearly an hour later, at 1:29PM ET, mission control in Houston and Moscow regained control of the station and wrested it back to its normal position. “The [Nauka] thrusters are no longer firing, we are back in attitude control, rates are stable,” Morgan told the US astronauts. “It’s safe to say that the remainder of the day is no longer going to happen as scheduled.”
Navias said the crew was safe. It wasn’t immediately clear what caused the erroneous thruster firings — Roscosmos, Russia’s space agency, would lead the investigation into the cause, Montalbano said. Seeing the ISS deviate from its attitude like it did on Thursday under the influence of errant jet firings is “definitely not something that happens on a regular basis,” Montalbano added, guessing an event like Thursday’s has only happened roughly three to four times in the space station’s 20-year history. The station’s other partners at the Japan Aerospace Exploration Agency and the European Space Agency were on call monitoring the health of the station during the event, Montalbano said.
The mishap forced NASA to postpone Boeing’s planned launch of its uncrewed Starliner capsule to the ISS, which was slated for Friday at 2:53PM ET. The launch is now scheduled for Tuesday, August 3rd at 1:20PM ET, the agency said in a statement.
NAUKA HAS HAD A ROUGH JOURNEY TO THE SPACE STATION
Nauka, which means science in Russian, launched from Russia’s Baikonur Cosmodrome in Kazakhstan last Wednesday after weeks of 11th-hour delays caused by issues with the module’s guidance system. Even though it launched last week, the module has a long history — its development started in 1995, and it was originally slated to launch in 2007. But launch delays and several changes to its design and purpose pushed its deployment back by years.
Nauka ran into problems almost immediately upon entering space. The spacecraft deployed its solar arrays 13 minutes after launch without a hitch, but propulsion and communications issues prevented the spacecraft from entering its intended orbit. Engineers and mission control in Moscow scrambled to come up with a fix, eventually powering up the spacecraft’s secondary thrusters to prevent Nauka from falling out of orbit and burning up in Earth’s atmosphere.
Nauka regained its footing in a normal orbit and carried on with its eight-day trek to the space station, where it docked autonomously.