Space Technology Special Report - Version B. July 2023 - 30

TECH BRIEFS
Eventually, the goal is to demonstrate
the technology at a range of sizes
that could interface with the smaller
commercial robotic landers up to
larger land ers. Analysis tools are
being developed under the project
so that different size variants of LSMS
can be developed fairly quickly for
different missions. LSMS is designed
to operate on the Moon, Mars, or
any kind of planetary body.
The team started looking at creating
a smaller version of the LSMS for the
smaller ro botic landing missions that
would precede a human mission.
The mini-LSMS has about a six-foot
reach and could add a similar set
of capabilities for offloading and
other tasks to the landers and could
demonstrate the LSMS technology on
the lunar surface at a smaller scale.
There are some unique capabilities that
could be provided with that particular
version such as charging a rover. The
rover could be offloaded with the miniLSMS
and the rover could perform a
mission and return. Because the LSMS
has a power connection at the tip, the
rover could be recharged, enabling
it to complete another mission.
If LSMS could be mounted on a
rover, it could act as a mobile tool for
digging and regolith operations or to
lift cargo off of a lander. Using a mobile
LSMS removes the need to land an
offloading device on every mission,
which is a weight and cost savings.
For more information, visit
www.nasa.gov/langley.
Lunar Surface Navigation System
Reverse-ephemeris approach enables low-cost lunar navigation solution.
Langley Research Center, Hampton, VA
S
cientists at NASA's Langley
Research Center have developed
a novel concept for a lunar navigation
system based on the reverse-ephemeris
technique. Typically, range-related
signal measurements from the Earth's
surface are used to locate and track
orbital objects (satellites) and establish
the ephemeris describing their orbits.
For this reverse-ephemeris lunar
navigation concept, the process is
reversed to give lunar surface position
fixes using the known ephemeris
of a satellite in lunar orbit.
In conventional GPS navigation
systems, the GPS satellite transmits
ephemeris data to a receiver on Earth
for determining position at the receiver
location. For the reverse-ephemeris
approach, the receiver becomes the
transmitter, and the satellite instead
serves more as a fixed reference
position with a known ephemeris. This
simplifies the satellite requirements
and mitigates potential navigational
disruptions that can otherwise arise in
navigation systems that utilize satellitebased
communications, for example,
from interference, jamming, etc.
The design consists of lunar surface
S-Band (2,400 2,450 MHz) 10 W
transceivers ranging with analog
translating transponders on a threesatellite
constellation in frozen elliptical
30 JULY 2023
Reverse-ephemeris navigation uses range and range rate measurement to obtain lunar surface position
fixes and navigation using a known ephemeris of an orbiting object or satellite. (Image: NASA)
orbits to provide continuous coverage
with service to 300 simultaneous
users over 1.8 MHz of bandwidth at
the transponder. Digital bases systems
are possible too. As compared to GPSbased
navigation requiring four or more
satellites costing hundreds of millions
of dollars, the new NASA concept is
based on using only three smallsats.
Only a few inexpensive smallsats
are required to implement a lunar
navigation system based on this
concept. Lunar navigation systems
will be needed for future Moon
missions, including, for example, for
rover navigation, mining operations,
exploration, etc. The inventors have
conducted analytical simulations to
demonstrate the versatility of this
innovation when used to support route
determination for various autonomous
or manned lunar surface operations.
NASA is actively seeking licensees to
commercialize this technology. Please
contact Licensing Concierge at AgencyPatent-Licensing@mail.nasa.gov
or
call at 202-358-7432 to initiate
licensing discussions. For more
information, visit https://technology.
nasa.gov/patent/LAR-TOPS-361.
SPACE TECHNOLOGY SPECIAL REPORT

http://www.nasa.gov/langley https://technology.nasa.gov/patent/LAR-TOPS-361 https://technology.nasa.gov/patent/LAR-TOPS-361

Space Technology Special Report - Version B. July 2023

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