Andrew M. Heafitz’s scientific contributions

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Publications (3)


The Mars Gravity Biosatellite: Thermal Design Strategies for a Rotating Partial Gravity Spacecraft
  • Article

July 2007

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14 Reads

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2 Citations

SAE Technical Papers

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Andrew M. Heafitz

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Jesse B. Marsh

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[...]

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A rotating spacecraft which encloses an atmospheric pressure vessel poses unique challenges for thermal control. In any given location, the artificial gravity vector is directed from the center to the periphery of the vehicle. Its local magnitude is determined by the mathematics of centripetal acceleration and is directly proportional to the radius at which the measurement is taken. Accordingly, we have a system with cylindrical symmetry, featuring microgravity at its core and increasingly strong gravity toward the periphery. The tendency for heat to move by convection toward the center of the craft is one consequence which must be addressed. In addition, fluid flow and thermal transfer is markedly different in this unique environment. Our strategy for thermal control represents a novel approach to address these constraints. We present data to theoretically and experimentally justify design decisions behind the Mars Gravity Biosatellite's proposed payload thermal control subassembly. The baseline system incorporates fans, thermoelectric coolers, heat fins and conducting plates to continuously and reliably remove thermal energy from the spacecraft's atmospheric pressure vessel. We present an assessment of a condensing heat exchanger with novel design enhancements to promote efficient operation in a partial gravity environment. Our approaches are validated by experimental data from a prototype of the thermal control subassembly within a new engineering mockup of the spacecraft's payload module. This work provides novel insights into issues of thermal control in artificial gravity environments. This research can inform ECLSS designs for future human-rated vehicles which may incorporate centrifugation as a countermeasure for musculoskeletal deconditioning.



The Mars Gravity Biosatellite: Innovations in Murine Motion Analysis and Life Support

July 2005

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33 Reads

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1 Citation

SAE Technical Papers

The MIT-based Mars Gravity Biosatellite payload engineering team has been engaged in designing and prototyping sensor and control systems for deployment within the rodent housing zone of the satellite, including novel video processing and atmospheric management tools. The video module will be a fully autonomous real-time analysis system that takes raw video footage of the specimen mice as input and distills those parameters which are of primary physiological importance from a scientific research perspective. Such signals include activity level, average velocity and rearing behavior, all of which will serve as indicators of animal health and vestibular function within the artificial gravity environment. Unlike raw video, these parameters require minimal storage space and can be readily transmitted to earth over a radio link of very low bandwidth. We present a collection of custom processing algorithms which are capable of accurately correlating video sequences with certain modes of behavior. We additionally present results which validate the performance of the proposed Mars Gravity atmospheric quality control module. The specific challenges of an extended-duration re-entry mission have required the development of low-mass and low-power systems for particulate filtration and contaminant control. Our approach has taken advantage of commercial off-the-shelf hardware where possible. Atmospherics systems on board the biosatellite are designed to maintain air quality and to continuously circulate clean, conditioned air to all fifteen specimen chambers. Sensors within the air circulation loop will monitor the concentrations of carbon dioxide, ammonia and other contaminants. Our design calls for a feedback system linked to the payload computer to control the temperature and humidity levels while particulate filters will remove dander, dust and other airborne contaminants.

Citations (2)


... One of the main challenges in the design of capsules or habitats is ammonia as a final product of chemical degradation of chemical waste such as urine [42]. According to international guidelines on the care and welfare of laboratory animals, elevated levels can cause alterations in biological responses [43]. ...

Reference:

Animals and Technology in Space: A Perspective from Aerospace Engineering to Veterinary Medicine
The Mars Gravity Biosatellite: Atmospheric Reconditioning Strategies for Extended-Duration Rodent Life Support
  • Citing Conference Paper
  • July 2007

SAE Technical Papers

... Fan location has been optimized, subject to both constraints in thermal flow as well as the data from the mockup experiments [5]. A more detailed discussion of the thermal control system can be found in References [5] and [8]. ...

The Mars Gravity Biosatellite: Thermal Design Strategies for a Rotating Partial Gravity Spacecraft
  • Citing Article
  • July 2007

SAE Technical Papers