This payload
developed by NMSU engineers was recently launched on the
UP Aerospace
SpaceLoft rocket from Spaceport America. (NASA photo)
(December 8, 2015) A
research project led by New Mexico State University Professor Ou Ma that began
in 2008 holds scientific, military and commercial promise for the growing use
of satellites. The innovative technology aims to enable spacecraft to dock with
satellites for rescue or servicing, thereby increasing the lifespan of these
pricey crafts that can spin off and become space junk.
“The inertia properties, such as mass, location of mass
center and moments of inertia, of a spacecraft can change in orbit due to fuel
consumption, hardware re-configuration, payload deployments or payload capture.
When this happens, the spacecraft’s control system needs to know the changes of
inertial properties to maintain proper control of the spacecraft,” said Ma, who
is the first recipient of the John Kaichiro Nakayama and Tome Miyaguchi
Nakayama Professorship for Research Excellence.
Ma’s Inertial Property Algorithm Verification (IPAV) Project
algorithm to identify the inertia properties of a spacecraft incorporates the
novel use of an onboard robotic arm. A large advantage of using a robotic arm
to identify inertia, over existing methods, is that it solar powered, requiring
no fuel, and measures velocities only (as opposed to measuring forces and
accelerations by the existing methods).
NMSU Mechanical
and Aerospace Engineering Professor Ou Ma
has been leading a
team of students since 2009 to develop an algorithm
to determine
changes in inertia for in-orbit spacecraft.
But testing and validation requires the system to float
freely and rotate arbitrarily in a 3D-space without gravity and therefore,
prohibitively difficult to do on the ground. Several other different methods
for spacecraft inertia identification have also been proposed, but none has as
of yet been tested in a real microgravity environment.
“Our approach is to reach this goal incrementally,” said Ma.
The group has twice tested the system in an aircraft parabolic flight that
provided 10-20 seconds of continuous microgravity time.
The algorithm has also been tested twice in suborbital
flight, providing 150-200 seconds of microgravity time, most recently as a
payload on the launch of the UP Aerospace SpaceLoft rocket from Spaceport
America in November 6, 2015.