NASA plans to use a lunar Global Positioning System (GPS) that will help the astronauts to find their way when they land on the moon’s surface sometime in 2024.
GPS is nothing but a U.S. military-operated system that relies on between 24 and 32 satellites orbiting above the Earth at any given time. It is a popular tool for everything from tracking devices to vehicle navigation systems.
As explained by NASA GPS is a system made up of three parts viz – satellites, ground stations and receivers. The ground stations monitor the satellites and the receivers are monitored by the ground stations. The distance is calculated by the receiver from four or more satellites to pinpoint a location.
The Lunar GPS will help in overcoming the navigational problems that was faced by Apollo astronauts in the 1960s and ’70s where they struggled in judging the distance to craters that were marked on their maps obtained from orbital imagery. The crew of 14 members missed a crater they planned to visit by only 100 feet i.e. 30 meters.
A special receiver is developed by NASA that could pick up GPS signals from GPS satellites all the way from lunar orbit around the Earth. Both surface missions as well as personnel piloting the Orion spacecraft and lunar Gateway space station that NASA plans to build would be supported by this lunar GPS.
However there is one technological challenge with this Lunar GPS. Generally GPS is most accurate at lower altitudes that are below the satellites’ orbit of 12,550 miles around 20,115 kilometers. To overcome this, NASA has already extended GPS-based navigation to higher altitudes for missions such as Geostationary Operational Environmental Satellites (GOES) and the Magnetospheric Multiscale Mission (MMS). The agency firmly believes that it is quite possible to go even higher.
At present NavCube is the latest GPS receiver concept in orbit. It combines the capabilities of MMS’s Navigator GPS and a flight computer platform called SpaceCube. NASA remarked that -“The GPS processing power of NavCube when combined with a receiver for lunar distances would definitely result in endowing with the capabilities required to use GPS at the moon.”