Among the dozens of spacecraft that have landed on the moon, none can come close to the period of NASA’s Lunar Reconnaissance Orbiter, which just lately completed a decade studying the sibling world.
The spacecraft, nicknamed LRO, started its work in lunar orbit in September 2009. Since then, the spacecraft has orbited the moon many times. Its job is repetitive, however, far from dull. On each circuit, the scientists watching its data from home can identify differences on the lunar surface as meteorites, and sometimes spacecraft, slam into the moon. The ability to see adjustments over time is what makes LRO’s longevity so useful to scientists.
LRO has outpaced every other lunar project by far. Its nearest competition comes from the twin ARTEMIS probes, which NASA constructed to study Earth’s magnetosphere then redirected mid-mission to lunar orbit. The two spacecraft have been at the moon from 2011 and are nonetheless operating.
The one different competition comes from NASA’s Explorer 35 project, which spent six years at the moon in the late sixties and concluded that the moon does not have a magnetosphere. Otherwise, lunar projects have tended to last about less than a year at most.
One of the riskiest times in the projects is during a lunar eclipse, when the spacecraft gets briefly stuck in darkness, with Earth obstructing the sun. Fortunately, LRO won’t expertise that situation again until May 2021, Petro mentioned, which shall be a comparatively short eclipse, after which again in May 2022.
Slipping occasionally into darkness remains to be more comfortable for a spacecraft than what robots face on the lunar floor. On the moon, both day and night last the equivalent of two weeks on Earth, and during that long darkness, temperatures fall. The bitter cold freezes whatever hardware does make it to the floor safely, reducing the life span of that machine.