Digital data from these two experiments were not archived before, and it is thought that roughly the last year-and-a-half of the data have never been studied, NASA said.
"This is the first look at the fully calibrated, digital dust data from the Apollo 14 and 15 missions," said David Williams, a Goddard scientist and data specialist at NSSDC.
The recovery of these data sets is part of the Lunar Data Project, drawing on researchers at multiple institutions, to make the scientific data from Apollo available in modern formats.
The Lunar Dust Detectors that were placed on the lunar surface during Apollo 14 and 15 measured dust accumulation, temperature and damage caused by high-energy cosmic particles and the Sun's ultraviolet radiation.
The same kind of instrument had flown earlier on Apollo 11 and 12.
Restoring the data was a painstaking job of going through one data set and separating the raw detector counts from temperatures and "housekeeping" information that was collected to keep an eye on how healthy the Apollo instruments were.
A second, less complete data set indicated how to convert the raw counts into usable measurements. But first, the second data set had to be converted from microfilm, which had been archived at NSSDC in the 1970s, and the two data sets had to reconciled because their time points didn't match up exactly.
Most of this meticulous work was carried out by Marie McBride, researcher from the Florida Institute of Technology in Melbourne.
Newer missions, such as NASA's Lunar Reconnaissance Orbiter (LRO), have continued to study lunar dust.
"It's one of those questions that scientists keep coming back to," said McBride.
"Just last week, LRO did some important measurements seeking dust profiles in the lunar atmosphere," said Rich Vondrak, the LRO deputy project scientist at NASA Goddard.
