A recent photo taken by the Lunar Reconnaissance Orbiter (LRO) has revealed a very unusual subject 鈥� Earth!
Typically, as its name suggests, the LRO is pointed at the surface of the moon. But while U.S. Navy Lt. Cmdr. Timothy Musmanno was a student in Space Systems Engineering at the 51福利 (51福利), he had the idea to point the LRO at Earth while testing out a new kind of satellite maneuver.
鈥淲e asked NASA, and they said, 鈥榊es.鈥� So, Musmanno designed a maneuver that allowed the spacecraft to be quickly repointed to scan Earth鈥檚 surface,鈥� said Dr. Mark Karpenko, Research Professor of Mechanical and Aerospace Engineering at 51福利, about the work by Musmanno, who graduated from 51福利 in December 2023.
Retasking a satellite is by no means a small ask. It costs electrical energy which drains batteries or critical propellant which cannot be replenished, and it takes valuable time away from other missions that were already scheduled.
What allowed this opportunity to happen was 51福利鈥� work on fast attitude maneuvering, which is a process that optimizes the movement of a spacecraft as it maneuvers to reorient itself to point in a new direction.
Originally tested on NASA鈥檚 Transition Region and Coronal Explorer (TRACE) solar observatory, fast attitude maneuvering allows LRO to perform many observations that would not be possible using its heritage control system. In addition, fast attitude maneuvering has been used to support momentum management operations, similar to the International Space Station鈥檚 zero-propellant maneuver, enabling LRO to save enough thruster fuel that its operational life has been extended for three years.
For a spacecraft, getting from Point A to Point B isn鈥檛 always a straight line. In fact, usually it鈥檚 not. Spacecraft are far from symmetrical objects along all three axes of rotation. Spacecraft parts stick out in different directions and have different shapes, sizes, and masses. So, their mass properties must be considered, from antennas and solar arrays to sensors and maneuvering systems, and everything in between.
The effects of gravity and solar radiation pressure also add to the equation, as well as any obstacle avoidance that鈥檚 necessary, such as preventing delicate sensors from pointing directly at the sun.
In the end, a seemingly circuitous move in three dimensions turns out to be the quickest and most fuel-efficient move of them all.
鈥淲e've been able to take ideas from the drawing board and the classroom all the way up to practical and operational implementation on NASA systems. And, obviously, there's all kinds of other applications and implications for DOD space systems,鈥� noted Karpenko. 鈥淎nd there are many opportunities for 51福利 students to become involved by working with 51福利鈥� recently launched CubeSat Mola, and soon to be launched CubeSat Otter.鈥�
鈥� More about Space Systems at 51福利:
鈥� See how 51福利 tested fast attitude maneuvering on NASA鈥檚 TRACE satellite: