80JSC027CTTR RFI 2026-09-29.pdf

Request for Information (RFI)

80JSC027CTTR

Measurement of Core Temperature and Thermoregulatory Responses during and after Spaceflight in Astronauts

NASA/Johnson Space Center (JSC) is hereby requesting information for Measurement of Core Temperature and Thermoregulatory Responses during and after Spaceflight in Astronauts.

Purpose of this RFI The information obtained will be used by NASA planning and acquisition strategy development.

NASA will use the information obtained through this RFI on a non-attribution basis. Providing data and information that is limited or restricted for use by NASA for that purpose would be of very little value and such restricted/limited data/information is not solicited. No information or questions received will be posted to any website or public access location. NASA may respond to the individual responses.

Description The National Aeronautics and Space Administration (NASA) Human Research Program (HRP) are requesting information for the characterization of core body temperature and thermoregulatory responses in astronauts before, during, and after spaceflight, including normal daily activities, exercise, and re-entry/landing. Work is targeted for completion of the International Space Station in 2032 but recommendations for other or future work may be extended to commercial spaceflight destinations in low Earth and Artemis mission. Given the short timeline for collecting this information, recommendations should focus on currently accepted approaches and technologies.

Appropriate responses to this RFI should address:

1. Recommendations for validated approach(es) to surveil and quantify core body temperature and thermoregulatory responses before spaceflight during spaceflight while at rest, during nominal spaceflight operations, and in the performance of exercise. Responses should include rationale and methodology. Prospective approaches should include technologies currently available for use in low-Earth orbit but also may identify those in development that may have applications during missions to the Moon and Mars where capabilities may be further constrained by vehicle stowage limitations, power allocations, and real-time communication delays with increasing need for Earth-independent operations. Retrospective methodologies might include novel approaches to analyze existing datasets available through the NASA Life Sciences Data Portal.

2. If applicable, recommendations for future spaceflight studies of thermoregulation should be specific to short- and long-duration missions in low-Earth orbit. Analogs might include relevant patient populations, parabolic flight, and suborbital flight.

The Human Research Program The Human Research Program (HRP) investigates and mitigates the highest risks to astronaut health and performance in exploration missions. The goal of the HRP is to provide human health and performance countermeasures, knowledge, technologies, and tools to enable safe, reliable, and productive human space exploration, and to ensure safe and productive human spaceflight.

The scope of these goals includes both the successful completion of exploration missions and the preservation of astronaut health over the life of the astronaut.

HRP has developed an Integrated Research Plan (IRP) to describe the requirements and notional approach to understanding and reducing the risks to human health and performance. The IRP describes the Program’s research activities that are intended to address the needs of human space exploration and serve HRP customers. The IRP illustrates the HRP’s research plan through the timescale of exploration missions of extended duration.

The Human Research Roadmap (https://humanresearchroadmap.nasa.gov) is a web-based version of the IRP that allows users to search HRP risks, gaps, and tasks.

Background Standards and requirements for extravehicular (EVA) and intravehicular (IVA) suits, vehicles, and habitats are based upon thermal modeling to predict when a core temperature threshold will be reached. Currently, models are based upon the assumption that resting core temperature in astronauts during spaceflight is equivalent to population estimates of core temperature without spaceflight exposure. The results of a recent ISS study that estimated core temperature from a sensor placed on the forehead, the “double sensor”, suggest that resting core temperature is ~1 °C higher in spaceflight than preflight (1). Further, the rate of increase in core temperature during exercise was greater during spaceflight than when the same exercise bout was performed preflight.

Other spaceflight and analog studies have reported similar findings and also observed altered skin temperature distribution reflecting the headward fluid shift as well as impaired sweating and skin blood responses to thermal stress (2–6). Anecdotal reports from crew include higher body temperature and prolonged recovery from exercise countermeasures and excessive heating and sweating during re-entry after ISS missions.

Without considering these altered thermoregulatory responses during spaceflight, the thermal models may inaccurately predict core temperature of astronauts, particularly during EVA and re-entry/landing, increasing the risk of impaired physical and cognitive performance, thermal injury, and orthostatic hypotension during vehicle acceleration and re-exposure to gravity. Inappropriate modeling parameters impact verification of requirements for hardware and countermeasures to thermal stress, such as the liquid cooling garment and environmental life support control systems (ECLSS), as well as operational guidelines constraining crew activity work rates and timelines during EVA and exercise countermeasures. For example, in one study of four Space Shuttle astronauts, despite the use of the liquid cooling garment in the IVA suit assembly core temperature measured with an ingestible thermistor pill increased ~0.5 °C during re-entry and landing above normal resting core temperature measured 48 hours before landing (7).

Esophageal and rectal temperatures are considered “gold standards” for measuring core temperature (8) but are not appropriate for routine monitoring during spaceflight (9). A non-https://humanresearchroadmap.nasa.gov/ invasive sensor, such as the “double sensor”, could be preferential for monitoring crewmember to improve comfort and compliance, address hygiene concerns of rectal and esophageal sensors, and enable data collection in operational contexts (10). However, during 24 hours of continuous monitoring in bed rest the agreement between simultaneous measures of rectal and double-sensor-derived estimates of core temperature varied between -0.72 and +0.5 C (10), and the double sensor has not been validated against accepted measures of core temperature during spaceflight. Characterizing core temperature with validated approaches during normal activities before, during, and after spaceflight, including 24-hour monitoring, exercise responses, and monitoring during re-entry and landing are key areas of interest.

References

1. Stahn AC, Werner A, Opatz O, Maggioni MA, Steinach M, von Ahlefeld VW, Moore A, Crucian BE, Smith SM, Zwart SR, Schlabs T, Mendt S, Trippel T, Koralewski E, Koch J, Choukèr A, Reitz G, Shang P, Röcker L, Kirsch KA, Gunga H-C. Increased core body temperature in astronauts during long-duration space missions. Sci Rep 7, 2017. doi: 10.1038/s41598-017-15560-w.

2. Lee SMC, Williams WJ, Schneider SM, New Collective Author. Role of skin blood flow and sweating rate in exercise thermoregulation after bed rest. J Appl Physiol (1985) 92: 2026–2034, 2002. doi: 10.1152/japplphysiol.00105.2001.

3. Shibasaki M, Wilson TE, Cui J, Levine BD, Crandall CG. Exercise throughout 6 degrees head-down tilt bed rest preserves thermoregulatory responses. J Appl Physiol 95: 1817–1823, 2003.

doi: 10.1152/japplphysiol.00188.2003.

4. Crandall CG, Shibasaki M, Wilson TE, Cui J, Levine BD. Prolonged head-down tilt exposure reduces maximal cutaneous vasodilator and sweating capacity in humans. J Appl Physiol 94:

2330–2336, 2003. doi: 10.1152/japplphysiol.00790.2002.

5. Wilson TE, Shibasaki M, Cui J, Levine BD, Crandall CG. Effects of 14 days of head-down tilt bed rest on cutaneous vasoconstrictor responses in humans. J Appl Physiol 94: 2113–2118, 2003.

doi: 10.1152/japplphysiol.00067.2002.

6. Fortney SM, Mikhaylov V, Lee SM, Kobzev Y, Gonzalez RR, Greenleaf JE. Body temperature and thermoregulation during submaximal exercise after 115-day spaceflight [Online]. Aviat Space Environ Med 69: 137–141, 1998. http://www.ncbi.nlm.nih.gov/pubmed/9491252 [12 Feb. 2011].

7. Rimmer D, Djik D, Rhonda J, Hoyt R, Pawelczyk JA. Efficacy of liquid cooling garments to minimize heat strain during Space Shuttle deorbit and landing. Medicine and Science in Sports and Exercise 31: S305, 1999.

8. Sawka MN, Wenger CB. Physiologic responses to acute exercise heat stress. In: Human performance physiology and environmental medicine at terrestrial extremes, edited by Pandolf KB, Sawka MN, Gonzalez RR. Indianapolis, IN: Benchmark Press, 1988, p. 97–151.

9. Gerbrandy J, Snell ES, Cranston WI. Oral, rectal, and oesophageal temperatures in relation to central temperature control in man. Clin Sci 13: 615–624, 1954.

10. Gunga H-C, Werner A, Stahn A, Steinach M, Schlabs T, Koralewski E, Kunz D, Belavý DL, Felsenberg D, Sattler F, Koch J. The Double Sensor-A non-invasive device to continuously monitor core temperature in humans on earth and in space. Respir Physiol Neurobiol 169 Suppl 1: S63-68, 2009. doi: 10.1016/j.resp.2009.04.005.

Additional Resources Office of the Chief Medical Officer Technical Brief on Venous Thrombosis:

https://www.nasa.gov/wp-content/uploads/2026/01/ochmo-mtb-007-venous-thrombosis-in-spaceflight.pdf

Human Spaceflight Standards https://www.nasa.gov/ochmo/human-spaceflight-and-aviation-standards/

Existing data from previous NASA spaceflight missions are available through the NASA Life Sciences Portal: https://www.nasa.gov/hrp/nlsp/

Response Instructions

All responses must be submitted electronically via email to Tracy L. Quintanilla at Tracy.L.Quintanilla@nasa.gov, and Katelyn R. Jaime at Katelyn.R.Jaime@nasa.gov. Please reference: RFI 80JSC027CTTR - Measurement of Core Temperature and Thermoregulatory Responses during and after Spaceflight in Astronauts, in any response.

This sources sought notice is for information and planning purposes only and is not to be construed as a commitment by the Government nor will the Government pay for information solicited.

Respondents will not be notified of the results of the evaluation. No solicitation exists. If a solicitation is released, it will be synopsized on SAM.gov. Interested firms are responsible for monitoring this website for the release of any presolicitation or solicitation notice.

https://www.nasa.gov/wp-content/uploads/2026/01/ochmo-mtb-007-venous-thrombosis-in-spaceflight.pdf https://www.nasa.gov/wp-content/uploads/2026/01/ochmo-mtb-007-venous-thrombosis-in-spaceflight.pdf https://www.nasa.gov/ochmo/human-spaceflight-and-aviation-standards/ https://www.nasa.gov/hrp/nlsp/