Cardiovascular Countermeasures

Exploration class missions will include multiple transitions between gravitational environments, sometimes after long periods in microgravity, which will impact the cardiovascular system. New and/or improved countermeasures and assessment tools are needed to mitigate the long-term health and operational risks associated with cardiovascular structural and functional changes during and following reduced-gravity timeframes of exploration missions.

The Cardiovascular Countermeasures capability area encompasses three projects.

1) Fluid Loading is one of the three end-of-mission countermeasures currently used by astronauts and cosmonauts to mitigate orthostatic intolerance (OI) during re-exposure to a gravitational environment. Both the NASA fluid loading protocol and that used by the Russian Space Agency (RSA) primarily utilize a combination of salt tablets and water to provide an oral isotonic solution, but these protocols differ in the timing of when the water and salt tablets are consumed relative to de-orbit and landing. Concerns about the palatability and tolerance have been raised by crewmembers consuming water and salt tablets, including reports of gastric distress, and vomiting, particularly when using NASA’s fluid loading protocol, which requires ingestion over a shorter period than the Russian protocol. An alternative electrolyte solution was developed by the NASA Johnson Space Center Space Food Systems Laboratory to address these concerns. The Cardiovascular and Vision Laboratory (CVL) developed and conducted a pilot study (n=5) in FY22 and determined that 15 subjects would be required to detect changes. In FY23 and FY24, the CVL conducted a study (n=15) to assess whether (1) the RSA protocol or (2) the new NASA electrolyte solution (Astrolyte) could expand plasma volume, but without the gastrointestinal (GI) side-effects. To do this, participants completed four study visits during which they consumed (1) no fluid loading (control), (2) water and salt tablets in 4 hours (RSA protocol), (3) Astrolyte in 4 hours (RSA protocol) or (4) Astrolyte in 1 hour (NASA protocol) (i.e. one protocol per visit). The overall purpose of this project is to determine whether Astrolyte can be used instead of water and salt tablets to effectively expand plasma volume with reduced gastrointestinal side-effects. These data will inform NASA and Commercial Provider flight surgeons on the effectiveness of Astrolyte and whether this alternative fluid loading protocol should be implemented to protect against OI while limiting GI symptoms and thereby increasing countermeasure adherence. The results of the fluid loading study will be integrated into a decision package for operational implementation on ISS in FY25.

2) The Orion Orthostatic Intolerance Garment (OIG) is a three-piece compression garment worn on the torso and both legs and is used to prevent crew from experiencing OI while performing reentry, landing, and egress tasks. While these custom-built garments have been adopted by the Orion program as well as for use by Boeing Starliner crewmembers, there are gaps in knowledge that may result in reduced efficacy during use upon return from long-duration spaceflight. First, while the specifications for the garment state certain pressures at various locations shall be achieved on the legs and torso, there has been no independent assessment on the variability of reaching these target pressures once built. Second, it is unclear what magnitude of change in anthropometry occurs during spaceflight due to the headward fluid shift, muscle atrophy, and/or other redistributions of body mass. If changes in anthropometry exceed the tolerance of the garment, the garment may no longer effectively reach target pressures and thereby not provide the intended compression. To address these concerns, this project will (1) assess the OIG skin contact pressure in newly constructed custom garments; 2) evaluate a hand-held camera and analysis pipeline that generates 3-dimensional anthropometric volumes that could be used for future preflight measurements to reduce crew time needed for manual measurements and can be considered for use during weightlessness to assess change in anthropometry during spaceflight. Data generated here will inform Artemis and/or Orion programs on whether updates are needed either to preflight fitting procedures and/or change in anthropometry during flight will require adjustments to the custom garments to adequately protect crew. Thus, this work has infusion points within Artemis and Orion programs. In addition, the Human Research Program (HRP) will sponsor a study that will evaluate the inflight use of the 3D camera and analysis pipeline to detect anthropometry changes across a long-duration mission, as well as gain insight from crew on the don/doff procedure of the OIG, to verify the operational concept of operations.

3) Crewmembers flying on Soyuz vehicles receive a pair of Roscosmos Braslet devices that are worn on the upper thighs and provide constriction to help alleviate symptoms associated with the headward fluid shift during the first few weeks of their International Space Station (ISS) mission. With United States Orbital Segment (USOS) crewmembers now flying on commercial vehicles such as the SpaceX Crew Dragon, Braslets are no longer available to them. The Cardiovascular and Vision Laboratory (CVL) has developed a veno-constrictive thigh cuff (VTC) device that is similar to the Braslet and is being tested in an HRP-funded flight study for consideration as a spaceflight associated neuro-ocular (SANS) countermeasure. A second HRP-funded study has also been initiated to assess whether VTC can be used to improve venous blood flow in the internal jugular vein early during spaceflight, thereby reducing the risk of thrombus formation. However, crewmembers have expressed a desire to obtain VTC for use on SpaceX Crew Dragon during ascent to ISS and during the first weeks of spaceflight on ISS in a manner similar to use of the Braslet. The CVL has worked closely with Space Medicine to develop and present this work to multiple boards to establish use of the VTC as an early inflight medical countermeasure and provide VTC for this use outside of the HRP-funded research studies. Funding from Mars Campaign Office (MCO)in FY23 and FY24 allowed for the procurement of VTC, support of CVL personnel to fit and train crewmembers on use of the VTC, and support for development of decision packages presented to various boards seeking approval for operational medical use of VTC. This effort resulted in a collaboration with HRP to fund the future acquisition and needed expertise as the VTCs are considered for infusion and operational use by ISS program. Artemis missions represent a second infusion point and operational adoption of this inflight countermeasure.

These countermeasures and assessment tools will be used to mitigate the inflight, postflight, and operational risks associated with cardiovascular structural and functional changes during and following reduced-gravity exploration missions. Implementation of improved fluid loading protocols, OI countermeasures, and VTC will reduce the risks of OI, thrombus formation, and the negative consequences associated with the adaptation to weightlessness following G transitions, respectively and therefore decrease risk to associated mission operations on other planetary surfaces.

This is a mature technology (TRL 8) — the realistic path in is usually NASA's Technology Transfer Program: licensing an existing NASA patent, or a Space Act Agreement to use NASA facilities/expertise directly. NASA also runs a startup licensing program with no upfront fee for companies formed to commercialize a specific NASA technology.

None of these are guaranteed paths for this specific project — TechPort itself doesn't have an "apply" button. Reaching out to the contact(s) above with a specific question is usually the fastest way to find out what's actually open.