Advanced Lightweight Rainfall Radiometer

Advanced Lightweight Rainfall Radiometer Enjoys Successful

Test Flights, Demonstrates Key Benefits for Future Space-based Missions

A new, lightweight passive microwave radiometer instrument

developed jointly by NASA Goddard Space Flight Center and the University

of Michigan successfully performed six calibration and science validation

flights on board NASA’s DC-8 aircraft. A recent graduate of the NASA Earth

Science Technology Office (ESTO), the Lightweight Rainfall Radiometer (LRR)

produced high-quality science data during one of the 6-hour flights (in

tandem with the JPL PR-2 airborne radar instrument) over a storm system

near Vancouver, WA.

The

X-band LRR, which is suitable for aircraft or space-based platforms, enables

markedly improved measurement of precipitation drop size and distribution

(at 10.7 GHz), as well as rain rate and surface wind speeds, when used

in conjunction with other instruments, such as the PR-2. With a receiver

less than 1/8th the size and using 50% less power than predecessors, the

LRR could lead to a space-borne 25 channel synthetic aperture radiometer

that would not be strictly limited by size and power requirements. The

core technology of the LRR – a synthetically thinned aperture radiometer

(STAR) – demonstrated the feasibility of a one-dimensional geometric interferometer

(no moving parts) for future NASA X-band missions. The lack of a mechanical

scanning apparatus found on traditional radiometers makes the LRR payload

smaller, lighter, and cheaper to launch while also reducing the complexity

and risk of the instrument. The team also conducted an antenna design

study that validated the STAR technology in the critical Ku- and Ka-bands.

Technical contributions came from the Center for Advanced

Microelectronics and Biology Research (CAMBR) at the University of Idaho,

Northrop Grumman Space Technology, the University of Massachusetts, and

NASA Dryden Flight Research Center. The task generated 17 publications

and four graduate-level theses.