A novel mission concept from NASA would lower a small satellite toward the surface of the moon on a 112-mile-long (180 kilometers) tether. One of the mission's goals would be to uncover the cause of strange, swirling patterns found in more than 100 locations on the lunar surface.

In May, NASA announced that it would invest funds in 10 mission concepts involving small satellites called cubesats. Recently, the agency released more details about one of those concepts — the Bi-sat Observations of the Lunar Atmosphere above Swirls (BOLAS) mission concept.

The mission would involve two small satellites, each about the size of a shoebox, connected vertically above the lunar surface by a long, thin tether, like some kind of miniature sky crane. The cubesat at one end of the tether would orbit the moon at an altitude of about 118 miles (189 km), which would place the second cubesat about 6 miles (9.6 km) above the lunar surface. From that position, the satellite could study those strange features in detail. [Amazing Moon Photos from NASA's Lunar Reconnaissance Orbiter]

To put a lone satellite into orbit around the moon at an altitude of 6 miles (9.6 km) above the surface, for an extended period of time, would require "a prohibitive amount of fuel," according to the statement. This is largely because of irregularities in the moon's gravity along its surface, which can push or pull a satellite out of orbit.

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Tethered satellites are therefore "a very natural approach for targeting lunar science," Michael Collier, a BOLAS co-investigator, said in the statement. Collier has been studying tether-based lunar missions since 2015 and called the BOLAS mission concept "groundbreaking."