The Jet Propulsion Laboratory (JPL) Urine Analyzer features miniaturized hardware elements to sample urine and measure concentrations of calcium, creatine, and creatinine. The unit is comprised of a hermetically sealed magnesium metal case plated with gold and a thin surface layer of silicon rubber, with approximately 5,300 cm³ of usable volume. The case is pressurized to 650 torr with nitrogen gas and contains a urine sample accumulator, a calcium analyzer, a creatine-creatinine analyzer, reagent storage bags, logic sequencers, a data handling system, and power converter.

When the Urine Transport System pumps its measured 10 ml quantities, the sample accumulator withdraws a 1 ml sample downstream. These samples are collected over a six-hour period, at the end of which the analysis cycle is initiated. Two microsyringes, each with a capacity of 85 µl, function as the calcium and creatine-creatinine analyzers. Syringe plungers are motor-driven, and by suitable valving the quartz barrels can be filled with appropriate volumes of urine and regent. Syringe contents can then be pumped into and out of a small mixing chamber several times, with the quartz barrels serving as a cuvette to measure the optical density or fluorescence intensity of the reaction mixture. At the end of the analysis, the products are emptied into a urine line leading to the urine storage tank. In addition to urine analyses, the unit performs a calibration analysis once every 24 hours. The unit can store enough reagent to preform this analysis sequence for thirty days.

Calcium: Calcium concentrations from samples and knowledge of total urine quantity on a related timeline provide the basis for calculating the total calcium excretion through urine during the mission. Calcium in the sample is detected optically after mixing with a chemical reagent, calcein, which produces a fluorescent complex, the intensity of which is an indicator of concentration.

Creatine-Creatinine: Creatine and creatinine are obtained by initially measuring free creatinine optically from a color development of urine mixed with picrate solution. A portion of the sample is treated with acid at high temperatures to convert the creatine to creatinine, and the color development process is repeated. Creatine is determined as total creatinine less the original creatinine.

Dimensions: 14 x 18 x 30 cm

Weight: 6.8 kg

Power: 6.5 W

Capacity: 30 days stored reagent

Sample Rate: 6 hours

Calcium, creatinine, and creatine level in urine, telemetered to the ground during the flight.

Auxiliary Ground Equipment: Console for processing data telemetered during the flight and simulating hardware functions during verification tests, including timing commands, telemetry readout.