The LADEE lunar orbiter has proved to be very successful, very interesting and very curious.
The Lunar Atmosphere and Dust Environment Explorer (LADEE) was a NASA lunar exploration and technology demonstration mission.
It was launched on a Minotaur V from the Mid-Atlantic Regional Spaceport on September 7, 2013.
During its seven-month mission, LADEE orbited around the Moon’s equator, and used instruments aboard the spacecraft to study the lunar exosphere and dust in the Moon’s vicinity.
Instruments included a dust detector, a neutral mass spectrometer, and an ultraviolet-visible spectrometer, as well as a technology demonstration consisting of a laser communications terminal.
The mission ended on April 18, 2014, when the spacecraft’s controllers intentionally crashed LADEE into the far side of the Moon.
The LADEE mission was designed to address three major science goals:
Determine the global density, composition, and time variability of the tenuous lunar exosphere before it is perturbed by further human activity.
Determine if the Apollo astronaut sightings of diffuse emission at tens of kilometers above the surface were sodium glow or dust.
Document the dust impactor environment (size-frequency) to help guide design engineering for the outpost and also future robotic missions.
and one technology demonstration goal:
Demonstrate two-way laser communication from lunar orbit.
The very successful aspect of the LADDE mission has been the photographic evidence provided by LADEE’s star tracker.
A star tracker is an optical device that measures the position(s) of star(s) using photocell(s) or a camera.
The animated images from LADEE’s star tracker [below] clearly demonstrate the brightening of the tracked stars just before they disappear below the lunar horizon.
In other words, as star light passes through the tenuous lunar atmosphere the star light causes the lunar atmosphere to fluoresce [and the star becomes brighter].
Images of the Moon captured by LADEE’s star tracker – 8 February 2014
The very interesting aspect of the LADDE mission is that the reality of electricity and florescence is finally creeping into the mainstream message.
There is some evidence that the Moon may have a tenuous atmosphere of moving particles constantly leaping up from and falling back to the Moon’s surface, giving rise to a “dust atmosphere” that looks static but is composed of dust particles in constant motion.
According to models proposed starting from 1956, on the daylit side of the Moon, solar ultraviolet and X-ray radiation is energetic enough to knock electrons out of atoms and molecules in the lunar soil.
Positive charges build up until the tiniest particles of lunar dust (measuring 1 micrometre and smaller) are repelled from the surface and lofted anywhere from metres to kilometres high, with the smallest particles reaching the highest altitudes.
Eventually they fall back toward the surface where the process is repeated.
On the night side, the dust is negatively charged by electrons in the solar wind.
Indeed, the “fountain model” suggests that the night side would charge up to higher voltages than the day side, possibly launching dust particles to higher velocities and altitudes.
This effect could be further enhanced during the portion of the Moon’s orbit where it passes through Earth’s magnetotail; see Magnetic field of the Moon for more detail.
On the terminator there could be significant horizontal electric fields forming between the day and night areas, resulting in horizontal dust transport.
Also, the Moon has been shown to have a “sodium tail” too faint to be detected by the human eye.
It is hundreds of thousands of miles long, and was discovered in 1998 as a result of Boston University scientists observing the Leonid meteor storm.
The Moon is constantly releasing atomic sodium gas from its surface, and solar radiation pressure accelerates the sodium atoms in the anti-sunward direction, forming an elongated tail which points away from the Sun.
It is to be determined whether ionized sodium gas atoms or charged dust are the cause of the reported Moon glows.
The very curious aspect of the LADDE mission was the decision to manoeuvre LADEE [three days before the solar lunar eclipse] so that it would specifically crash into the dark side of the moon.
LADEE mission managers expect the spacecraft will impact the moon’s surface on or before April 21.
On April 11, ground controllers at NASA’s Ames Research Center in Moffett Field, Calif., will command LADEE to perform its final orbital maintenance maneuver prior to a 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 just on the edge of what it was designed to survive.
This final maneuver will ensure that LADEE’s trajectory will impact the far side of the moon, which is not in view of Earth and away from any previous lunar mission landings.
There are no plans to target a particular impact location on the lunar surface, and the exact date and time depends on several factors.
Ground controllers at NASA’s Ames Research Center in Moffett Field, Calif., have confirmed that NASA’s Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft impacted the surface of the moon, as planned, between 9:30 and 10:22 p.m. PDT Thursday, April 17.
During impact, engineers believe the LADEE spacecraft, the size of a vending machine, broke apart, with most of the spacecraft’s material heating up several hundred degrees – or even vaporizing – at the surface.
Any material that remained is likely buried in shallow craters.
“At the time of impact, LADEE was traveling at a speed of 3,600 miles per hour – about three times the speed of a high-powered rifle bullet,” said Rick Elphic, LADEE project scientist at Ames.
“There’s nothing gentle about impact at these speeds – it’s just a question of whether LADEE made a localized craterlet on a hillside or scattered debris across a flat area.
It will be interesting to see what kind of feature LADEE has created.”
In early April, the spacecraft was commanded to carry out maneuvers that would lower its closest approach to the lunar surface.
The new orbit brought LADEE to altitudes below one mile (two kilometers) above the lunar surface.
This is lower than most commercial airliners fly above Earth, enabling scientists to gather unprecedented science measurements.
On April 11, LADEE performed a final maneuver to ensure a trajectory that caused the spacecraft to impact the far side of the moon, which is not in view of Earth or near any previous lunar mission landings.
LADEE also survived the total lunar eclipse on April 14 to 15. This demonstrated the spacecraft’s ability to endure low temperatures and a drain on batteries as it, and the moon, passed through Earth’s deep shadow.
Although NASA states they had “no plans to target a particular impact location” they deliberately manoeuvred LADEE so that its lunar impact was specifically “not in view of Earth”.
This is really curious because:
1) NASA [in their search for extraterrestrial water] went to great lengths to crash Deep Impact into comet Temple.
2) NASA [in their search for extraterrestrial water] are currently manoeuvring the Rosetta spacecraft so they can attempt a landing on Comet 67P/Churyumov-Gerasimenko later in the year.
3) NASA announced that they had detected water on the surface of the moon last year.
NASA-Funded Scientists Detect Water on Moon’s Surface that Hints at Water Below
NASA-funded lunar research has yielded evidence of water locked in mineral grains on the surface of the moon from an unknown source deep beneath the surface.
Using data from NASA’s Moon Mineralogy Mapper (M3) instrument aboard the Indian Space Research Organization’s Chandrayaan-1 spacecraft, scientists remotely detected magmatic water, or water that originates from deep within the moon’s interior, on the surface of the moon.
The only other clue is that NASA wanted to protect its lunar archaeology and keep LADEE “away from any previous lunar mission landings”.
However, given the exposed and pock-marked nature of the lunar surface this archaeological rationale hardly seems credible.
Impact events are continually occurring on the lunar surface.
The most common events are those associated with micrometeorites, as might be encountered during meteor showers.
Impact flashes from such events have been detected from multiple and simultaneous Earth-based observations.
Tables of impacts recorded by video cameras exist for years since 2005 many of which are associated with meteor showers.
This map displays an approximate distribution of transient lunar phenomena.
It is based on a monochrome map by Barbara Middlehurst and Patrick Moore that was published in the book, On the Moon, 2001.
Red dots indicate TLP that appeared to the observer as a reddish cloud.
Yellow dots are all other events
Therefore, unless NASA is planning to offer archaeological field trips to the moon, it seems likely there was something about this lunar impact [like a dust cloud or electric discharge] they wanted to keep under wraps.