Engineering topics

Arya, Maneesh

Publications and source records attributed to Arya, Maneesh.

4 records

NASA NTRS2011

Why Should Humans Explore a Near Earth Asteroid and What Factors Drive the Medical Risks?

The National Aeronautics and Space Administration (NASA) is currently considering plans for the human exploration of a Near Earth Asteroid (NEA). Reasons for undertaking the human exploration of a NEA include increasing the scientific understanding of the origins of our solar system, and developing technology for the exploration of more distant destinations such as Mars. Most mission scenarios have a duration on the order of several months or a year, most of which is spent in transit to and from the NEA. The choice of a particular NEA destination determines the mission duration and guides the types of exploration activities that can be performed on and near the NEA. NASA s Human Research Program (HRP) has identified short and long-term health risks associated with such missions and begun characterizing the level of risk. Some risk drivers are well known from missions to low Earth orbit and the Moon (e.g., the limited mass, volume, and power available for the medical care system). Other factors emerge as major drivers for NEA missions. Some are fundamental characteristics of the mission parameters (e.g., mission duration, distance) and others are strongly dependent on the specifics of how the mission is implemented (e.g., isolation and confinement). Careful consideration of these factors will be required for safe and effective missions to NEAs.

Kundrot, Craig E.↗

NASA NTRS2010

Interplanetary Transit Simulations Using the International Space Station

It has been suggested that the International Space Station (ISS) be utilized to simulate the transit portion of long-duration missions to Mars and near-Earth asteroids (NEA). The ISS offers a unique environment for such simulations, providing researchers with a high-fidelity platform to study, enhance, and validate technologies and countermeasures for these long-duration missions. From a space life sciences perspective, two major categories of human research activities have been identified that will harness the various capabilities of the ISS during the proposed simulations. The first category includes studies that require the use of the ISS, typically because of the need for prolonged weightlessness. The ISS is currently the only available platform capable of providing researchers with access to a weightless environment over an extended duration. In addition, the ISS offers high fidelity for other fundamental space environmental factors, such as isolation, distance, and accessibility. The second category includes studies that do not require use of the ISS in the strictest sense, but can exploit its use to maximize their scientific return more efficiently and productively than in ground-based simulations. In addition to conducting Mars and NEA simulations on the ISS, increasing the current increment duration on the ISS from 6 months to a longer duration will provide opportunities for enhanced and focused research relevant to long-duration Mars and NEA missions. Although it is currently believed that increasing the ISS crew increment duration to 9 or even 12 months will pose little additional risk to crewmembers, additional medical monitoring capabilities may be required beyond those currently used for the ISS operations. The use of the ISS to simulate aspects of Mars and NEA missions seems practical, and it is recommended that planning begin soon, in close consultation with all international partners.

Charles, J. B.↗

NASA NTRS2007

Gender Differences in Cardiovascular Tolerance to Short Arm Centrifugation

In preparation for the NASA Artificial Gravity (AG) pilot study, the tolerability of the proposed AG parameters was tested in 11 ambulatory human subjects (6m, 5w) by exposing each to a short arm centrifuge trial. Subjects were oriented in the supine position (but inclined 6deg head down) on one arm of the centrifuge, and the rotation rate (30.6-33.4 rpm) and radial position of the feet were set to produce 2.5G of equivalent gravitational load at the force plate directly beneath the feet, 1G at the level of the mediastinum, and approximately 0.55G at the labyrinth. Amongst the 6 men participating in this preliminary study, 5 completed at least 60 minutes of the trial successfully with no adverse sequelae. However, amongst the female cohort the test was stopped by the medical monitor before 60 min in all but one case, with pre-syncope listed as the reason for termination in all cases. Mean time before abort of the centrifuge run amongst the women was 33.2 +/- 20.97 min. It is known that women have a greater predisposition to syncope during orthostatic stress, under normal tilt table conditions, during LBNP, and following space flight. The reasons for this difference are the subject of some debate, but anthropometric factors, the vasoactive effects of sex hormones, gender differences in susceptibility to motion sickness, catecholamine levels, ability to augment total peripheral resistance in response to orthostatic stress, and structural differences in cardiac anatomy and physiology have all been suggested. This finding led to the exclusion of women from the AG pilot study. Clearly if AG is to be employed as a multi-system countermeasure it must provide physiological protection at rotation rates within the tolerance limits of all potential astronauts. Further investigation of the responses of women to centrifugation will be necessary to determine how to adjust AG parameters for tolerance by female subjects before a more detailed investigation of the appropriate dose in terms of G load, rotation rate, exposure duration and frequency can be performed.

Fong, Kevin J.↗

NASA NTRS2006

Response of Ambulatory Human Subjects to Artificial Gravity (Short Radius Centrifugation)

Prolonged exposure to microgravity results in significant adaptive changes, including cardiovascular deconditioning, muscle atrophy, bone loss, and sensorimotor reorganization, that place individuals at risk for performing physical activities after return to a gravitational environment. Planned missions to Mars include unprecedented hypogravity exposures that would likely result in unacceptable risks to crews. Artificial gravity (AG) paradigms may offer multisystem protection from the untoward effects of adaptation to the microgravity of space or the hypogravity of planetary surfaces. While the most effective AG designs would employ a rotating spacecraft, perceived issues may preclude their use. The questions of whether and how intermittent AG produced by a short radius centrifuge (SRC) could be employed have therefore sprung to the forefront of operational research. In preparing for a series of intermittent AG trials in subjects deconditioned by bed rest, we have examined the responses of several healthy, ambulatory subjects to SRC exposures.

Paloski, William H.↗