In late May 2026, NASA astronaut Don Pettit floated into the Columbus laboratory module aboard the International Space Station and began configuring a compact European workout machine that had never been tested in orbit. Pettit and his Expedition 74 crewmates are putting the device through its paces while also scanning their own blood vessels to track what weightlessness does to the human circulatory system. The two efforts are running in parallel, and together they target the same long-term problem: keeping astronauts healthy on missions that could last years rather than months.
The exercise hardware, called the European Enhanced Exploration Exercise Device (E4D), was built by the European Space Agency specifically for deep-space missions where room and weight are at a premium. Crew members have been configuring the device for its first on-orbit technology demonstration, which will test whether it can deliver a full range of resistance exercises without shaking the station hard enough to disturb nearby experiments. Vibration isolation is a serious engineering challenge on a crewed spacecraft. A 2023 NASA technical report detailed the modeling and simulation work behind stabilization approaches for exercise systems. That pre-flight analysis, completed roughly three years before the E4D’s 2026 on-orbit deployment, addressed the theoretical challenges the hardware was designed to overcome.
The ISS already has a capable resistance trainer, the Advanced Resistive Exercise Device (ARED), which has been a cornerstone of crew fitness since 2008. But ARED is large, heavy, and engineered for the relatively spacious ISS. The E4D is meant to prove that a more compact system can do comparable work inside the tighter confines of a lunar Gateway module or a Mars transit vehicle.
Tracking blood flow in real time
While the E4D testing moves forward, crew members have been using a newly delivered Ultrasound 3 imaging unit to scan veins and arteries as part of two related but distinct investigations.
The first, called Venous Flow, focuses on how fluid redistributes through the body when gravity disappears. In March 2026, astronauts scanned jugular veins while electrodes recorded heart activity, building a real-time picture of blood movement in the upper body. Those sessions were not one-off checks. Repeated scan rounds continued over multiple weeks through the spring of 2026, creating a longitudinal dataset rather than a single snapshot.
The second study, Vascular Aging, uses arterial ultrasounds and other physiological measures to assess whether spaceflight accelerates the stiffening of blood vessel walls. That investigation has been running across several ISS expeditions, meaning the Expedition 74 data can be compared against a growing archive from earlier crews. The two studies appear to share imaging hardware and likely overlap in crew time, but they ask different questions: Venous Flow is about where blood goes, while Vascular Aging is about what happens to the vessels themselves over time.
Why exercise and vascular research belong together
The pairing is not coincidental. Resistance exercise is one of the primary countermeasures against cardiovascular deconditioning in orbit. Muscles contract, blood pressure responds, and vessel walls experience mechanical stress that helps maintain their elasticity. If researchers can eventually match real-time vascular imaging with data from a new generation of adaptive exercise equipment, they open the door to adjusting workout protocols based on measurable changes in a crew member’s circulatory system, rather than relying on fixed schedules written before launch.
That integrated approach has not been formally announced as an active research objective by ESA or NASA. The two activities appear in separate weekly operations reports, and no published study design explicitly links E4D sessions to immediate vascular scan results. But the building blocks are now physically present on the same station, operated by the same crew, during the same expedition window.
What the public record does not yet show
No preliminary performance data from the E4D has been released. The engineering analyses available through NASA’s technical reports describe pre-flight modeling, not post-installation metrics showing how the device actually behaves during use. Whether the E4D meets its design targets for vibration suppression, load range, and exercise variety will likely require months of on-orbit testing before results are published.
On the vascular side, no raw physiological results or individual-level findings have been disclosed. NASA’s daily operations logs confirm that scans occurred and that cardiac data was captured, but they do not report what those measurements revealed about any specific astronaut’s cardiovascular health. Summary-level descriptions of the Vascular Aging study list the types of data collected without sharing outcomes.
“We have not seen any direct crew commentary on either the E4D’s usability or the experience of repeated ultrasound sessions in public reporting,” is the honest summary of the available record. Institutional overviews describe what the hardware does and what data it collects, but astronaut feedback on comfort, time burden, or practical limitations remains unavailable as of June 2026.
What Expedition 74’s parallel tests mean for missions beyond low Earth orbit
NASA and its international partners are planning crewed missions to the lunar surface under the Artemis program and studying architectures for eventual Mars transits. Both scenarios involve months or years of altered gravity, confinement, and limited medical resources. Countermeasures that can be adjusted in flight, guided by objective measurements rather than preplanned protocols, could prove essential.
The E4D is a concrete test case. Its compact footprint and vibration-control design are tailored to vehicles that lack the ISS’s generous volume and structural mass. If it performs as intended, it could anchor fitness programs on spacecraft where ARED simply would not fit. Meanwhile, the Venous Flow and Vascular Aging studies are assembling a more detailed map of how microgravity reshapes the circulatory system, from large central veins down to smaller arterial branches.
Connecting these threads into a single, actionable model of cardiovascular adaptation will require formal study designs, peer-reviewed analysis, and likely several more expeditions’ worth of data. The current evidence confirms that Expedition 74 is advancing both exercise technology and vascular science aboard the ISS. It does not yet answer the harder question: whether these tools, used together, can keep crews safe on the longer voyages now taking shape on mission planners’ timelines.
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*This article was researched with the help of AI, with human editors creating the final content.
