Richard T. Jennings

Visual stability of laser vision correction in an astronaut on a Soyuz mission to the International Space Station

UNLABELLED This report documents the effects of photorefractive keratectomy (PRK) in an astronaut during a 12-day Russian Soyuz mission to the International Space Station in 2008. Changing environmental conditions of launch, microgravity exposure, and reentry create an extremely dynamic ocular environment. Although many normal eyes have repeatedly been subject to such stresses, the effect on an eye with a relatively thin cornea as a result of PRK has not been reported. This report suggests that PRK is a safe, effective, and well-tolerated procedure in astronauts during space flight. FINANCIAL DISCLOSURE No author has a financial or proprietary interest in any material or method mentioned.

Pharmacological Agents for the Prevention and Treatment of Toxic Radiation Exposure in Spaceflight

BACKGROUND Astronauts are exposed to toxic ionizing radiation sources, including galactic cosmic radiation and solar particle events (SPE). Exposure to these radiation sources can lead to cataracts, heritable genetic mutations, cancer, acute life-threatening physiological compromise, and death. Current countermeasures focus on spacecraft shielding and creation of heavily shielded safe havens. At issue is the extraordinarily high cost of launching these heavy structures into space and their inability to provide adequate shielding from heavy ions at a feasible shield thickness. Pharmacological enhancement of cellular radiation resistance, an alternative method to limiting radiation toxicity, has received less attention. METHODS We have conducted an extensive literature review and critical evaluation of the scientific data pertaining to this field of study. Publications for review were identified through a Medline search using relevant terms, including radiotherapeutics, galactic cosmic radiation, radiopharmacology, radioprotectants, radiation countermeasures, solar particles, solar flares, radiation toxicity, and radiotoxicity. RESULTS We identified 15 agents with significant radiation dose reduction factors, ranging from 1.1 to 2.4, in experimental models. Of these, only amifostine is FDA approved for use in treating radiation toxicity. CONCLUSIONS Current data do not support the use of radiopreventive agents in the treatment of low-level ionizing radiation exposures. However, pharmacological countermeasures should be instituted for life-threatening, high-level radiation exposures, as occur with SPE. Given the catastrophic effects of SPE, the risk of toxicity from radioprotective agents is warranted. The current data supports treatment with high-dose amifostine (at 910 mg m(-2)) 30 min prior to radiation exposure.

Suborbital commercial spacefl ight crewmember medical issues

As directed by the Council of the Aerospace Medical Association, the Commercial Spaceflight Working Group has developed the following position paper concerning medical issues for commercial suborbital spaceflight crewmembers. This position paper has been approved by the AsMA Council to become a policy of the AsMA.

Gynecological and reproductive issues for women in space: a review.

Women have been an integral part of United States space crews since the initial flight of Dr. Sally Ride in 1983, and a total of 40 women have been selected as U.S. astronauts. This article examines the reproductive and gynecological aspects of selecting, training, medically certifying, and flying women in space. Gynecological data from the astronaut selection cycles in 1991 to 1997 are reviewed. In addition, the reproductive implications of delaying childbearing for a career as an astronaut and the impact of new technology such as assisted reproductive techniques are examined. The reproductive outcomes of U.S. female astronauts after spaceflight are also presented. Because women have gained considerable operational experience on the Shuttle and Mir, the unique operational considerations for preflight certification, menstruation control and hygiene, contraception, and urination are discussed. Medical and surgical implications for women on long-duration missions to remote locations are still evolving, and enabling technologies for health care delivery are being developed. There has been considerable progress in the development of zero-gravity surgical techniques, including laparoscopy, thoracoscopy, and laparotomy. The concepts of prevention of illness, conversion of surgical conditions to medically treatable conditions, and surgical intervention for long-duration spaceflights are explored in detail. There currently are no operational gynecological or reproductive constraints for women that would preclude their successful participation in the exploration of our nearby solar system.

Astronaut medical selection during the shuttle era: 1981-2011.

INTRODUCTION U.S. astronauts undergo extensive job-related screening and medical examinations prior to selection in order to identify candidates optimally suited for careers in spaceflight. Screening medical standards evolved over many years and after extensive spaceflight experience. These standards assess health-related risks for each astronaut candidate, minimizing the potential for medical impact on future mission success. This document discusses the evolution of the Shuttle-era medical selection standards and the most common reasons for medical dis-qualification of applicants. METHODS Data for astronaut candidate finalists were compiled from medical records and NASA archives from the period of 1978 to 2004 and were retrospectively reviewed for medically disqualifying conditions. RESULTS During Shuttle selection cycles, a total of 372 applicants were disqualified due to 425 medical concerns. The most common disqualifying conditions included visual, cardiovascular, psychiatric, and behavioral disorders. During this time period, three major expert panel reviews resulted in refinements and alterations to selection standards for future cycles. DISCUSSION Shuttle-era screening, testing, and specialist evaluations evolved through periodic expert reviews, evidence-based medicine, and astronaut medical care experience. The Shuttle medical program contributed to the development and implementation of NASA and international standards, longitudinal data collection, improved medical care, and occupational surveillance models. The lessons learned from the Shuttle program serve as the basis for medical selection for the ISS, exploration-class missions, and for those expected to participate in commercial spaceflight.

The ISS flight of Richard Garriott: a template for medicine and science investigation on future spaceflight participant missions.

BACKGROUND A total of eight commercial spaceflight participants have launched to the International Space Station (ISS) on Soyuz vehicles. Based on an older mean age compared to career astronauts and an increased prevalence of medical conditions, spaceflight participants have provided the opportunity to learn about the effect of space travel on crewmembers with medical problems. The 12-d Soyuz TMA-13/12 ISS flight of spaceflight participant Richard Garriott included medical factors that required preflight intervention, risk mitigation strategies, and provided the opportunity for medical study on-orbit. Equally important, Mr. Garriott conducted extensive medical, scientific, and educational payload operations during the flight. These included 7 medical experiments and a total of 15 scientific projects such as protein crystal growth, Earth observations/photography, educational projects with schools, and amateur radio. The medical studies included the effect of microgravity on immune function, sleep, bone loss, corneal refractive surgery, low back pain, motion perception, and intraocular pressure. CONCLUSION The overall mission success resulted from non-bureaucratic agility in mission planning, cooperation with investigators from NASA, ISS, International Partners, and the Korean Aerospace Research Institute, in-flight support and leadership from a team with spaceflight and Capcom experience, and overall mission support from the ISS program. This article focuses on science opportunities that suborbital and orbital spaceflight participant flights offer and suggests that the science program on Richard Garriotts flight be considered a model for future orbital and suborbital missions. The medical challenges are presented in a companion article.

Human reproductive issues in space.

Animal studies in space or analogous environments have suggested that there may be problems in the reproductive sphere; such factors might limit mankinds ability to live and work for extended periods of time in microgravity or on non-terrestrial planetary surfaces. A review of reproductive functioning in animal species studied during space flight demonstrated that most species were affected significantly by the absence of gravity and/or the presence of radiation. These two factors induced alterations in normal reproductive functioning independently of, as well as in combination with, each other. Based on animal models, we have identified several potential problem areas regarding human reproductive physiology and functioning in the space environment. While there are no current space flight investigations, the animal studies suggest priorities for future research in human reproduction. Such studies will be critical for the successful colonization of the space frontier.

Giant hepatic hemangioma and cross-fused ectopic kidney in a spaceflight participant.

Commercial spaceflight participants are typically older than traditional astronauts and often have medical conditions that make medical certification for flight difficult. This case report considers a 43-yr-old spaceflight participant who planned a short-duration Soyuz flight to the International Space Station (ISS). While he participated in many hazardous activities such as parachuting, hang gliding, scuba diving, Antarctic and jungle exploration, and deep sea submersible operations, he knew that several of his medical conditions precluded serving as a career astronaut. At the time of his initial spaceflight prescreen examination, he was known to have previous bilateral photorefractive keratectomy (PRK) for myopia and a cross-fused left ectopic kidney that would be disqualifying for a career astronaut. During the evaluation for the left single cross-fused ectopic kidney, a giant hepatic hemangioma was also discovered. In order to medically qualify for flight, the giant hepatic hemangioma was surgically removed. This case summary investigat*es the implications of a single cross-fused left ectopic kidney and the decision process and treatment implications for spaceflight medical certification in an individual with an asymptomatic giant hepatic hemangioma.