Working with Lunar orbiter to characterize Mini-RF

Earlier this month, NASA used the 21-meter tracking antenna at Morehead State University to successfully characterize the higher of two radar frequencies of the LRO/Mini-RF instrument.

Mini-RF is a synthetic aperture radar (SAR) currently investigating the Moon’s surface aboard the Lunar Reconnaissance Orbiter (LRO). Launched on June 18, 2009, LRO uses its seven instruments to explore the Moon from a 50-kilometer (31 mile) polar orbit. Mini-RF is an advanced instrument that functions as a synthetic aperture radar, as well as a communications system, operating at both 2,380 and 7,140 MHz frequencies. The LRO/Mini-RF instrument is operated by engineers and scientists at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, MD.

Specifically, Mini-RF is used to map the poles of the Moon and search for water ice in permanently shadowed regions. In addition, it serves as a technical demonstration of a unique, miniaturized, dual-use RF instrument (radar and communications).

The LRO/Mini-RF team collaborated with Kentucky Space, a joint enterprise involving public organizations, colleges, universities and private companies in Kentucky, to conduct its first in-flight calibration of the Mini-RF instrument at 7,140 MHz. This was accomplished through the use of the 21-meter Morehead State University ground station together with instrumentation developed at APL for this calibration.

The purpose of the experiment was to characterize the transmitter and receiver of Mini-RF’s system and confirm the alignment of the Mini-RF antenna.

Dr. Ben Malphrus, Chair of the Morehead State University (MSU) Department of Earth and Space Sciences and the project lead for MSU described the LRO calibration experiment as an incredible opportunity for Kentucky Space to participate in NASA’s on-going investigation of the Moon. Prior to the May Mini-RF/LRO test, students and staff at MSU and APL staff spent several months preparing the 21-meter ground station by using radio sources (stars) to calibrate and improve its pointing accuracy.

According to Dr. Malphrus, "Improving pointing calibration will help increase precision at all frequencies. In addition to developing new capabilities at X-band, the team pushed the 21m to new precision and learned a great deal about its capabilities."

The series of calibration experiments was undertaken by the APL LRO/Mini-RF team working with a team of Morehead Space Science undergraduate students and staff. The undergraduate students participated in the development of instrumentation and processes involved, as well as operation of the 21-m ground station during the experiments. The students also participate in reducing and analyzing the experiment data—all providing outstanding hands-on experience for training undergraduate students.

“Overall, the test campaign was a tremendous success,” says Ron Schulze, LRO/Mini-RF calibration lead engineer from APL.  “While we’re still evaluating the data that were received on the ground and recorded by Mini-RF, our initial analysis indicates that the Mini-RF transmit/receive performance and antenna pointing is sufficient for the science goals of the program.”  

“The innovative solution that the APL team and Kentucky Space developed and implemented to perform this valuable test for Mini-RF was a perfect example of how NASA missions can work with educational institutions,” said Jason Crusan, Chief Technologist for Space Operations at NASA Headquarters.  “To witness such a successful collaborative effort demonstrates the potential to develop the next generation workforce through allowing them to participate directly on missions.”

This project was supported by NASA, the Johns Hopkins University/Applied Physics Laboratory, Kentucky Space, Morehead State University, and the Kentucky Space Grants Consortium.

Kentucky Space is a consortium including the Kentucky Science and Technology Corporation, the University of Kentucky, University of Louisville, Morehead State University, Western Kentucky University, Murray State University, the Kentucky Community and Technical College System, and Belcan Engineering.

Kentucky Space was created in 2006 with the goal of promoting space research, business ventures, talent development, and the creation of a space economy in Kentucky.