Lunar Atmosphere and Dust Environment Explorer
Launch Date: September 2013
Program(s):Robotic Lunar Exploration
Goals:The Lunar Atmosphere and Dust Environment Explorer (LADEE) is designed to study the Moon's thin exosphere and the lunar dust environment. An “exosphere” is an atmosphere that is so thin and tenuous that molecules don’t collide with each other. Studying the Moon’s exosphere will help scientists understand other planetary bodies with exospheres too, like Mercury and some of Jupiter’s bigger moons. The orbiter will determine the density, composition and temporal and spatial variability of the Moon's exosphere to help us understand where the species in the exosphere come from and the role of the solar wind, lunar surface and interior, and meteoric infall as sources. The mission will also examine the density and temporal and spatial variability of dust particles that may get lofted into the atmosphere.
The mission will also test several new technologies, including a modular spacecraft bus that may reduce the cost of future deep space missions and demonstrate two-way high rate laser communication for the first time from the Moon.
Accomplishments: This spacecraft is fully integrated and in final environmental testing.
10 Aug 2013 - 13 Oct 2013:Launch Window
LADEE will determine the global density, composition, and time variability of the fragile lunar atmosphere before it is perturbed by any future human activities.
An artist's concept of NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft orbiting the moon and preparing to fire its maneuvering thrusters to maintain a safe orbital altitude. Image credit: NASA Ames / Dana Berry
Because the Moon's atmosphere is so thin, disturbances could quickly swamp its natural composition.
If scientists are ever to know the lunar atmosphere in a relatively natural state, now is the time to look.
Mission Type: Orbiter
Launch Vehicle: Minotaur V
Launch Site: Wallops Flight Facility, Wallops Island, United States
NASA Center: Ames Research Center
Spacecraft Mass: 383 kg
Spacecraft Power: 295 W
Project Manager: Butler P. Hine, III, Ames Research Center
Total Cost: Total mission cost is $263 million.
The Lunar Atmosphere and Dust Environment Explorer (LADEE) is the first mission dedicated to understanding the thin atmosphere and dust at the Moon; what we learn on LADEE will help us understand the thin atmospheres and dust environments elsewhere too – at Mercury, the moons of Mars, as well as larger asteroids and the moons of the outer planets.
The scientific objectives of the mission are to:
- Determine the composition of the lunar atmosphere and the processes that control its distribution and variability.
- Characterize the lunar exospheric dust environment.
One of the motivations for this mission is to determine the global density, composition, and time variability of the fragile lunar atmosphere before it is perturbed by any future human activities. We are also trying to solve a mystery from the last time humans were on the Moon, we would like to determine if the Apollo astronaut sightings of diffuse emission at 10s of km above the surface were caused by sodium glow or dust.
The science orbit will last 100 days. The orbiter is carrying three science instruments. The neutral mass spectrometer (NMS) will directly measure the concentration of different atmospheric species. The ultraviolet/visible spectrometer (UVS) will measure both the atmosphere and dust. The Lunar Dust Experiment (LDEX) will directly measure dust particles. The total science payload mass is 50 kg.
There is also a technology demonstration, the Lunar Laser Communication Demonstration, designed to demonstrate a new method of sending and receiving data from missions using lasers rather than radio signals. The lasercom from Earth to lunar orbit will have a down link data rate of 622 Mb/s, compared to our current methods, which only get about 100 Mb/s.
The mission will detect and constrain the abundances of atmospheric species expected to be prevalent at orbital altitudes between 20 and 150 km. It will help us understand the sources of these components, for example, whether they are due to the solar wind and its interactions with the lunar surface, or release from the soil, or radiogenic sources. It will also seek to determine the density, time variability and spatial distribution of possible lofted lunar dust, to help us understand the physical mechanisms by which such lofting might occur, and what role the interactions with the Sun plays in these processes.
LADEE will spend about 2.5 months reaching the Moon, getting into its science orbit, and checking out systems before its 100 day science mission starts. The nominal science orbit will be a near-circular retrograde (clockwise) equatorial orbit with a period of 113 minutes at about 50 km above the surface. The periselene (closest approach) will be over the sunrise terminator. After the science mission is complete the orbiter will impact the lunar surface.