atmospheric science: The study of the atmosphere.

commands: These are the instructions sent to the payload. For example, an experiment may not be started on the ground (or while the balloon is rising) so instructions would be sent to the payload after the balloon achieves float altitude to start the instruments.

cosmic ray: Very energetic particles (atomic nuclei) that constantly bombard the earth's atmosphere. Balloons do not fly high enough to actually detect cosmic rays, but they do detect their by-products.

detector calibration: Detectors need to have a reference to determine what they actually "see." This is accomplished by looking at a known quantity and basing the output of the detector which is "seeing" an unknown source on that known quantity. The act of determining this reference is call detector calibration.

ELBBO: ELBBO (Extended Life Balloon Borne Observatories Program) is an experiment whose goal was to investigate electrodynamics and plasma processes in the atmosphere.

gamma ray: This is an electromagnetic wave just like visible light. It is in the part of the spectrum which is beyond human ability to see. Gamma rays are very high energy electromagnetic waves.

helium: A non-flammable gas used in balloons. Helium is the second lightest of all the gases. The lightest gas is hydrogen. Hydrogen is highly explosive when mixed with oxygen.

interface package: A set of electronics that is used for communication.

infrared: This is an electromagnetic wave just like visible light. It is in the part of the spectrum which is beyond human ability to see (in fact it is just beyond the red light we do see, hence the name). Normally associated with heat.

payloads: The instruments carried by a balloon. Usually this consists of everything in the gondola though in the case of TopHat the payload also includes the instruments on top of the balloon.

squib: A small quantity of high explosives usually used for directed blasts.

stratosphere: An upper layer of the atmosphere that contains the ozone layer oft mentioned in the news.

super-pressure balloons: These are balloons that have an internal pressure which is different from the external pressure at float - this is primarily to ensure stability over long periods of time at float. Extra strong material must be used to prevent these balloons from exploding.

TDRSS: TDRSS (Tracking and Data Relay Satellite System) is a collection of TDR satellites used to relay data from one site to another site that are not directly accessible to each other.

telemetry: Data transmitted and recorded by an experiment. In this case it is the additional information beyond the scientific data.

visible: Astrophysics using the portion of the electromagnetic spectrum that is visible to us.

ultraviolet: This is an electromagnetic wave just like visible light. It is in the part of the spectrum which is beyond human ability to see. It derives its name from the fact that these waves are beyond the violet light that we do see with our naked eyes.

X-ray: This is an electromagnetic wave just like visible light. It is in the part of the spectrum which is beyond human ability to see. X-rays are very high energy electromagnetic waves, but not as energetic as gamma rays.

zero-pressure differential: This states that the difference between the internal pressure of the balloon and external pressure of the balloon (i.e. the surrounding atmosphere) at the ends of the tubes is zero.