ascent stage: The pressurized upper stage of the Lunar Lander in which the crew pilots the lander from lunar orbit to the lunar surface and return. The ascent stage takes off from the descent stage, leaving the latter behind on the surface.
AU: astronomical unit
AX-2: NASA Ames Research Center Experimental Suit 2, designed during the Apollo program as a lunar surface hard suit to bend at the waist and rotate in the torso so that the crew member can reach down to the ground with one hand. Fabricated from fiberglass.
AX-5: NASA Ames Research Center Experimental Suit 5, designed during the Space Station Advanced Development program to provide a durable hard suit for extended operations in zero gravity. Fabricated from numerically milled aluminum forgings.
BEIR: Committee on Biological Effects of Ionizing Radiation
BEVALAC: An early, high-energy synchrotron accelerator constructed in the 1950s at Lawrence Berkeley National Laboratory and used to discover the antiproton. Closed in 1992.
biological end point: effect or response being assessed, e.g., cancer, cataracts
bipolar device: a type of semiconductor whose operation is based on both majority and minority carriers
BNL: Brookhaven National Laboratory
BRYNTRN: a computer code for simulating baryon transport
carbon composite: A structural material that can substitute for aluminum and other metals in the construction of many parts of a spacecraft, notably the pressure vessel shell. Composite may incorporate boron, epoxy, polyethylene, hydrogen, or other materials that enhance radiation shielding properties.
cargo habitat: a crew habitat that the Lunar Lander carries for delivery to the Lunar Outpost as a key part of the “Outpost-first” strategy
CHMO: chief health and medical officer
chronic effects: long-term effects of exposure to radiation; includes cancer, cataracts, and nervous system damage
CI: confidence interval
CME: coronal mass ejection, an explosion of plasma released from the atmosphere (or corona) of the Sun
CNS: central nervous system
computerized anatomical male/female: a model of human geometry used to evaluate radiation doses at various points inside the body
Constellation system: the complete ensemble of launch vehicles, flight vehicles, ground support, support services, and lunar and planetary surface systems associated with the Vision for Space Exploration