The astronaut showed worn socks that flew billions of kilometers

The astronaut showed worn socks that flew billions of kilometers

Astronaut Don Pettit shared a picture from his photo collection. In the early years of the International Space Station, the suspension of the exercise bike developed a design defect. A chemical engineer corrected the problem with the help of his worn socks.


The ISS crew has been at the station for months. The human body in conditions of microgravity easily loses muscle and bone mass, because it does not feel the usual loads of the Earth’s gravity. Regular training is required to keep the body in good shape.

There are several simulators for physical education at the ISS. One of them is the Cycle Ergometer with Vibration Isolation System installed in the “Destiny” module. CEVIS is an exercise bike. The “Vibration Isolation System” in the name implies that the device is attached to the rest of the ISS through a special vibration damping system. NASA documentation indicates the vibration profile during training on CEVIS.

In general, the entire rich arsenal of simulators of the ISS is equipped with dampers. This is done so as not to interfere with experiments sensitive to shaking and not to shake the structure. Otherwise, the equipment is almost earthly. The treadmill of the American segment of the ISS – COLBERT (Combined Operational Load-Bearing External Resistance Treadmill) – is most often mentioned in the documentation under the name T2 or COLBERT/T2. (This happened because of the antics of a telecomic who called to spoil the online voting.) This track of the well-known manufacturer Woodway USA is attached to the structures of the “Tranquility” module with a vibration damping system developed by the project contractor – Wyle Laboratories.

Moreover, during almost a quarter of a century of operation of the station, some simulators managed to change and improve. The Advanced Resistive Exercise Device vacuum bar for strength exercises was installed on the ISS in 2009. This was a marked improvement: its predecessor, the Interim Resistive Exercise Device, did not have a good suspension. Similarly runs [sic] the BD-2 track in the “Zirka” module, equipped with a vibration protection system developed by Samara University, replaced the earlier Treadmill Vibration Isolation System in 2013.

Video of 2022

Equipment is changed, but the complexity of on-orbit repairs is taken into account when designing simulators. On BD-2, in 2019, the torn canvas was replaced, and in 2022, the torsion drives were replaced. In both cases, there was a long planning of works. For example, the canvas was torn in October 2019, and it was replaced in just two months, since it arrived on Progress MS-13 in December.

Don Pettit described how he got the CEVIS vibration damping system up and running with improvised means. The first CEVIS appeared on the ISS early: the simulator arrived back in 2001 on the shuttle Discovery.

The CEVIS vibration damping system looks like a ball of wire that does not transmit the vibration of the exercise bike to the rest of the station. The frame of the exercise bike communicates with the rest of the ISS through four such springs. Already in space, a structural flaw was revealed: sharp movements from the exercise bike were beyond the wire’s ability to restrain, and the two opposite ends of the damping device met together. At the same time, the wire broke, due to which it often had to be changed.

Pettit was part of one of the early expeditions to the station, the ISS-6. In 2002, the astronaut came up with an idea: he rolled 4 pairs of worn socks into one dense lump and pushed it inside the spring. This prevented excessive deformation of the wire.

NASA’s engineering team on Earth approved the change, and it stayed that way. In 2008, Pettit entered flight STS-126 on a 15-day visit to the ISS, and the socks were still in place. It was then that the photo was taken, which is placed next to the executioner in this post.

The fact is documented in NASA sources. In 2013, the agency ran a media campaign with the hashtag #trainlikemike, which featured videos and tweets. Here, the protagonist of the campaign, Michael Hopkins, talks about the CEVIS exercise bike. A spring with socks flashes in the astronaut’s hands

Only 9 years later, in 2011, during the ISS-29, an instruction to change socks came from Earth, and astronaut Mike Fossum stuffed the newly worn pair into the suspension. In the same year, as part of the 30th expedition, Pettit again arrived at the station. Don did not like Fossum’s work: the result seemed too egg-shaped. Pettit untied the socks and folded them into tight spheres.

IN video clip as of late August 2023, Warren Hoburg confirms that the socks are in place in each of the four springs

To this day, these lumps of socks remain at the station. Jokingly or seriously, Pettit calls them his legacy in building and maintaining the ISS.

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