The Lunar Atmosphere and Dust Environment Explorer (LADEE) will meet its glorious end on 21 April.
Currently it is cruising one to two miles above the surface as it collects data on the mysteries of the Moon's atmosphere.
Scientists hope this data will help answer a long-standing question: Was lunar dust, electrically charged by sunlight, responsible for the pre-sunrise glow detected during several Apollo missions above the lunar horizon?
LADEE also is gathering detailed information about the structure and composition of the thin lunar atmosphere.
A thorough understanding of these characteristics of our nearest celestial neighbour will help researchers understand other bodies in the solar system, such as large asteroids, Mercury, and the moons of outer planets.
Because of the low altitude there is a chance it could impact before the intended date.
Butler Hine, LADEE project manager at Ames, said: "The moon's gravity field is so lumpy, and the terrain is so highly variable with crater ridges and valleys that frequent manoeuvres are required or the LADEE spacecraft will impact the moon’s surface.
"Even if we perform all manoeuvre perfectly, there's still a chance LADEE could impact the moon sometime before April 21, which is when we expect LADEE's orbit to naturally decay after using all the fuel onboard."
Until mid-April, ground controllers will continue to fire the LADEE altitude control thrusters once a week to keep the observatory in its target orbit.
On April 11, LADEE will perform its final orbital maintenance manoeuvre before the total lunar eclipse on April 15, when Earth’s shadow passes over the moon.
This eclipse, which will last approximately four hours, exposes the spacecraft to conditions at the limits of what it was designed to withstand.
Hine said: "We're very eager to see how LADEE handles the prolonged exposure to the intense cold of this eclipse, and we've used flight data to predict that most of the spacecraft should be fine."
Launched in September 2013, from NASA's Wallops Flight Facility on Wallops Island, Va., the vending machine-size spacecraft has been orbiting the moon since Oct. 6. On Nov. 10, LADEE began gathering science data, and on Nov. 20, the spacecraft entered its science orbit around the moon's equator.
LADEE has been in extended mission operations following a highly successful 100-day primary science phase.Suggest a correction