July three, 2019 – GPS, a satellite-based navigation system utilized by an estimated 4 billion individuals worldwide to determine the place they’re on Earth at any second, could possibly be used to pilot in and round lunar orbit throughout future Artemis missions.
A crew at NASA is growing a particular receiver that might be capable of
decide up location alerts supplied by the 24 to 32 operational World
Positioning System satellites, higher often called GPS. GPS is operated by
the U.S. navy about 12,550 miles above Earth’s floor, and is open
to anybody with a GPS receiver. These identical GPS alerts present location
information utilized in car navigation methods, interactive maps, and monitoring
gadgets of all kinds, amongst many different functions.
Such a functionality might quickly additionally present navigational options to astronauts and floor controllers working the Orion spacecraft, the Gateway in orbit across the Moon, and lunar floor missions.
GPS is a system made up of three elements: satellites, floor stations,
and receivers. The bottom stations monitor the satellites, and a
receiver, like these present in a telephone or automotive, is continually listening
for a sign from these satellites. The receiver calculates its distance
from 4 or extra satellites to pinpoint a location. As a substitute of
navigating streets on Earth, a spacecraft geared up with a complicated GPS
receiver might quickly be paired with exact mapping information to assist astronauts
monitor their areas within the huge ocean of house between the shores of
Earth and the Moon, or throughout the craterous lunar floor.
Navigation companies close to the Moon have traditionally been supplied by
NASA’s communications networks. The GPS community, which has extra
satellites and might higher accommodate extra customers, might assist ease
the load on NASA’s networks, thereby liberating up that bandwidth for different
“What we’re making an attempt to do is use present infrastructure for
navigational functions, as an alternative of constructing new infrastructure across the
Moon,” mentioned engineer and Principal Investigator Munther Hassouneh at
Goddard Area Flight Heart in Greenbelt, Maryland.
NASA has been working to increase GPS-based navigation to excessive
altitudes, above the orbit of the GPS satellites, for greater than a decade
and now believes its use on the Moon, which is about 250,000 miles from
Earth, might be executed.
“We’re utilizing infrastructure that was constructed for floor navigation on
Earth for functions past Earth,” mentioned Jason Mitchell, chief
technologist for Goddard’s Mission Engineering and Methods Evaluation
Division. “Its use for higher-altitude navigation has now been firmly
established with the success of missions like Magnetospheric Multiscale
mission (MMS) and the Geostationary Operational Environmental Satellites
(GOES). In actual fact, with MMS, we’re already almost half method to the Moon.”
The lunar GPS receiver relies on the Goddard-developed Navigator GPS, which engineers started growing within the early 2000s particularly for NASA’s MMS mission, the first-ever mission to review how the Solar’s and Earth’s magnetic fields join and disconnect. The purpose was to construct a spacecraft-based receiver and related algorithms that might shortly purchase and monitor GPS radiowaves even in weak-signal areas. Navigator is now thought-about an enabling know-how for MMS.
With out Navigator GPS, the 4 identically geared up MMS spacecraft
couldn’t fly of their tight formation in an orbit that reaches so far as
115,000 miles from Earth’s middle — far above the GPS constellation and
about midway to the Moon.
“NASA has been pushing high-altitude GPS know-how for years,” mentioned Luke Winternitz, the MMS Navigator receiver system architect. “GPS across the Moon is the following frontier.”
Expertise Enhancements Required
Extending the usage of GPS to the Moon would require some enhancements
over MMS’s onboard GPS system, together with a high-gain antenna, an
enhanced clock, and up to date electronics.
The crew is addressing these challenges — because of Goddard’s
years-long funding in essential enabling applied sciences, notably
within the space of miniaturization.
“Goddard’s IRAD (Inside Analysis and Improvement) program has positioned us to unravel among the issues related to utilizing GPS in and across the Moon,” Mitchell mentioned, including smaller, extra sturdy GPS receiver might additionally help the navigational wants of SmallSats, together with a brand new SmallSat platform Goddard engineers at the moment are growing.
The crew’s present lunar GPS receiver idea relies on NavCube, a brand new functionality developed from the merger of MMS’s Navigator GPS and SpaceCube, a reconfigurable, very quick flight pc platform. The extra highly effective NavCube, developed with IRAD help, was lately launched to the Worldwide Area Station the place it’s anticipated to make use of its enhanced capability to course of GPS alerts as a part of an indication of X-ray communications in house.
The GPS processing energy of NavCube mixed with a receiver for
lunar distances ought to present the capabilities wanted to make use of GPS on the
Moon. Earlier this yr, the crew simulated the efficiency of the
lunar GPS receiver and located promising outcomes. By the top of this yr,
the crew plans to finish the lunar NavCube prototype and
discover choices for a flight demonstration.
“NASA and our companions are returning to the Moon for good,” Mitchell
mentioned. “NASA will want navigation capabilities reminiscent of this for a
sustainable presence on the Moon, and we’re growing enabling
applied sciences to make it occur.”