A misfired thruster on the Russian module briefly nudged the station off course.
A few hours after the long-awaited Russian Nauka module docked with the International Space Station (ISS), a misfired thruster on the station’s newest component sent the ISS briefly off course—triggering a first-ever so-called “spacecraft emergency” by NASA mission control.
Initial reports claimed that the orbital platform tilted about 45 degrees—but since then, more details have surfaced. According to NASA Flight Director Zebulon Scoville, the ISS “spun one-and-a-half revolutions—about 540 degrees—before coming to a stop upside down. The space station then did a 180-degree forward flip to get back to its original orientation.”
At 12:34 p.m. Eastern time, three hours after Nauka (also known as the Multipurpose Laboratory Module) successfully docked with the ISS, the module’s thrusters fired automatically. The ISS’s systems detected a shift away from the station’s nominal attitude orientation. In response, the station’s gyros kicked in to correct the attitude—but were unable to do so.
About eight minutes later, the ISS’s deviation surpassed acceptable limits, and a Loss of Attitude emergency was triggered. This put NASA and the ISS at top priority in the global geostationary satellite tracking network in geostationary orbit—meaning all of NASA’s attention was directed at the station. NASA gave ISS the order to free drift, shutting the gyros down to reduce the stress on the attachment points that connect the station’s modules together.
Emergency control was transferred to the main Russian component—the Zvezda service module that Nauka had docked with. Zvezda then tried to reorient the station by firing its own thrusters, pushing back against Nauka in an orbital wrestling match.
That match lasted about 45 minutes, during which time the Russian controllers tried to shut down Nauka’s thrusters. Nauka kept pushing the ISS off course, and Zvezda could slow but not stop it. Nauka was slowly overpowering Zvezda and the rest of the station—until eventually, Nauka simply ran out of fuel and the thrusters went quiet. Russian controllers then deployed the Progress MS-17 spacecraft, an automated Russian cargo ship that had docked with the ISS in July, to use its own thrusters to maneuver the station back to attitude control and stabilize its orientation.
The torque generated by Nauka added to the stress load of some of the station’s structures, and the change in direction misaligned the ISS’s solar panels—pointing them in the wrong direction. “You risk some things getting too warm or too cold,” said Montalbano. The direction change also meant that the aim of station’s antennas was changed. In fact, communications with station crew were disrupted twice during the incident—first for four minutes, and later for seven.
While the two massive structures were pushing against each other, the station’s movement never went over 0.5 degrees per second—the crew didn’t even feel it.
Nauka’s thrusters were permanently disabled remotely when the ISS passed over Russian ground stations. Roscosmos, Russia’s space agency, is leading the investigation into the incident. And follow-up examinations by NASA have revealed no damage to the station.
The 23-ton, 42-foot-long cylindrical Nauka module is primarily a science laboratory focused on materials science and biotechnology. It also has an extra sleeping pod and a bathroom. It can generate oxygen for up to six people and features a water purifier that can recycle urine into drinkable water. Nauka is equipped with solar panels that provide power to the Russian section of the station, making it less dependent on electricity from the NASA-owned side.
ESA astronaut takes us on a tour of the Nauka module.
The module also features the European Robotic Arm, created by the European Space Agency (ESA), which will serve as Nauka’s main manipulator. The arm has seven joints and is capable of anchoring itself to the ISS and traveling, hand over hand, to different fixed points on the Russian section of the station. The technology can carry out tasks automatically or semiautomatically, can receive commands from inside and outside the station, and can be preprogrammed to take certain actions. It will be used to install new parts and assist with astronaut spacewalks.
In order to make room for Nauka, the Russians recently jettisoned an older module. The Pirs module, which had been used as a docking port for almost two decades, was the first module to be decommissioned and discarded completely in space. After being shut down by Russian cosmonauts, the Progress spacecraft undocked it and sent Pirs to burn up in the atmosphere.
Nauka has been in design and development for more than two decades, with repeated delays due to manufacturing flaws and financing issues. Russia had been the only major ISS player without its own lab on the station—until now. And Nauka is one of the biggest modules on the station. Once its electrical and command circuits are linked up with the rest of the station, which will be done through a series of spacewalks, Nauka is expected to provide a significant boost to Russia’s space science program.
The Russian module had problems on its trip to the ISS as well. An engine glitch in orbit caused Nauka to fly as an autonomous spacecraft for several days. The module had deployed its solar panels and antennas as planned, but the engines didn’t fire to raise its orbit—a problem that could have ended the mission entirely. Roscosmos engineers were able to fix the glitch by the time Nauka arrived at the station, though the module’s course still required correction a mere hour before docking. Clearly, there were sustained difficulties with the module’s engines long before Nauka even arrived at the ISS.
And docking with the station was more complicated as well. Nauka’s automatic docking system didn’t work as planned; the Russian craft and modules are all equipped with the Kurs automatic docking system, which enables them to rendezvous and dock with the ISS under their own engine power. When Nauka’s system malfunctioned, Russian astronaut Oleg Novitsky, who is on board the ISS, had to take over manual control to guide the module home. Nauka’s approach was way off, too; the station had to reposition itself in a special attitude—about 90 degrees upward—to align itself with the module’s docking axis.
Tense moments docking Nauka with the ISS.
It’s important to note that, while the incident was classified as an emergency, the crew were never in immediate danger. “Obviously, when you have a loss of attitude control, that’s something you want to address right away,” said space station program manager Joel Montalbano. “But the crew was never in any immediate emergency or anything like that.” Had the situation deteriorated, the crew could have fled to a SpaceX crew capsule designed to function as a lifeboat in emergencies.
The incident has raised serious concerns nevertheless, with the future of the ISS already a topic of debate. “Somebody needs to expose the decision process that allowed NASA to approve the ISS docking of a powerful thruster-equipped module without the on-site real-time capability to quickly disarm that system in an emergency,” said James Oberg, a former NASA engineer who has extensively studied the Russian space program.
The Nauka incident could possibly have ended in disaster—but the ISS, and quick-thinking members of the U.S. and Russian space programs, were up to the challenge. Let’s hope something like this doesn’t happen again.
Read more about what’s been going on at the ISS at SpaceX’s Crew Dragon Launches Into History.
