A robotic mission to the moon has intentionally crashed into the lunar surface. Before the programmed crash, scientists collected data from the craft, called LADEE, an acronym for Lunar Atmosphere and Dust Environment Explorer.
LADEE has been orbiting the moon since October. The tube-shaped probe is about the size of a vending machine, with solar panels mounted on its sides. Its mission was to study dust in the lunar atmosphere. Project manager Butler Hine with NASA’s Ames Research Center says LADEE began taking measurements at 250 kilometers above the lunar surface.
"And as we got lower into the science orbit, the dust density just kept increasing," he said.
So, where does all that dust come from? And how does it move about the moon? Flying at an altitude of between 20-50 kilometers, LADEE’s array of instruments took some 700,000 measurements to answer those questions.
"And one of the things that we saw is that it is almost a continuous shroud around the moon and some of the production of the dust is done by meteorite impacts to the moon and that’s kind of a continuous rain on the moon and so the source of the dust is kind of a continuous thing," he said.
Hine says while a moon-based observatory would have to account for the dust in its optical design, dust would not pose a problem for spacecraft or human activity on the surface.
"And what we’ve seen so far is that while there’s a lot of dust, the levels are high, we haven’t seen any indication that that level of dust is a hazard at all," he said. "We haven’t seen any degradation of our spacecraft systems and the dust levels that we do detect wouldn’t pose a significant risk to any future mission."
LADEE discovered traces of argon, methane, carbon dioxide and other substances. It also successfully tested a broadband communications system between Earth and the moon. Hine says LADEE’s new modular space bus design could be replicated on a range of missions.
"The spacecraft can be put together in different ways depending on the type of mission. For instance this bus [design] can be configured as a lunar orbiter, which is what LADEE is… It is designed for the environment anywhere between the Earth orbit and Mars orbit," he said. "It’s even designed as a lunar lander configuration. So you can take some of the bus modules, put them together in a fashion where it could land on the moon."
Among the tense moments for Mission Control in California was a lunar eclipse during LADEE’s final days, which put the solar array in darkness. For four hours, the craft had to depend on its battery to protect its systems from freezing.
"We basically prepared the spacecraft ahead of the eclipse, where we turned off the science instruments to conserve power," he said. "We turned on and off different heaters and configured them to go on and off and then we let it fly through the eclipse."
"The challenge was that we’re not getting any power generated and we’re drawing a lot more power during the eclipse to keep things warm."
But LADEE did not need much more power. The craft was programmed to self-destruct on the far side of the moon away from the historic sites where astronauts have landed. It continued to gather and send data in its last days, as it flew just two kilometers above the lunar surface, en route to the planned crash