Treadmill aboard the Zvezda Service Module
Among its many life-support functions, the Zvezda Service Module hosted a treadmill for the crews of the International Space Station, ISS. The custom-built device designed to operate in space was more than a regular fitness machine. Due to harmful effects of weightlessness on space travelers' bodies, extensive exercise became absolutely crucial for maintaining good health of the crews during long-duration missions and for helping in the adaptation to Earth's gravity after their return. At the same time, the treadmill had to operate with minimum vibration in order not to disturb sensitive experiments and sensors on the outpost.
On May 21, 2013, Pavel Vinogradov works on dismantling the old treadmill system onboard the ISS. Credit: NASA
From TVIS to BD-2
Initially, the Zvezda Service Module was outfitted with a US-built hardware, officially known as Treadmill Vibration Isolation System or TVIS. It was designed to insulate the space station from even minute vibrations caused by hundreds of hours of exercise logged by crews. However very early into the mission of the service module, the device proved to be prone to failures. Both mechanical and electronic parts of the system were malfunctioning, Russian engineers said.
By November 2001, the Stafford-Anfimov expert commission, which oversaw the joint Russian-US manned space efforts, considered replacing a US-built treadmill with a Russian unit, originally developed for the Buran orbiter, the Soviet equivalent of the US Space Shuttle.
The device went through rigorous testing and could meet most of the requirements for the space station, engineers at Russia's chief manned space flight contractor, RKK Energia, believed. According to Russian sources, the Buran's hardware would be able to perform 80 percent of the requirements for the ISS treadmill. In comparison to previous Russian space station-based exercise machines, Burans unit was more compact. The Burans treadmill could also be mounted on the existing system of the isolation from vibration.
However the problem apparently remained unresolved during the entire decade of the station's assembly, during which Russian engineers developed an upgraded exercise machine designated BD-2 from Russian Begushaya Dorozhka, which can be literally translated as the "Running Path," a Russian term for a treadmill. It featured its own vibration isolation system, the treadmill itself with a built-in control system, the control console, and the fixation system, which would prevent the crew member from "flying away" during the exercise.
On Oct. 31, 2012, the Progress M-17M cargo ship lifted off with the first set of components for the BD-2 treadmill. On April 24, 2013, Progress M-18M followed with the rest of hardware for the BD-2 system.
On May 20, 2013, the crew members of the Soyuz TMA-08M spacecraft, Pavel Vinogradov and Aleksandr Misurkin dismantled the old TVIS hardware and a day later they started assembling the BD-2 treadmill.
(To be continued)
An early Russian treadmill developed for use in space. Copyright © 2011 Anatoly Zak
According to a NASA caption for this photo: "Expedition 36 Commander Pavel Vinogradov (seen at photo center) with Russia's Federal Space Agency (Roscosmos) is dwarfed by the Treadmill Vibration Isolation System (TVIS) in the Zvezda service module of the International Space Station as the three current crew members do some moving around and changing out on the orbital outpost. Another TVIS will replace this one." The caption did not mention that the US device had to be replaced with Russian hardware. Credit: NASA