On Friday, at 11:27 p.m. US east coast local time (04:27 GMT on Saturday), NASA will launch the unmanned LADEE probe from the Wallops rocket facility.  LADEE (Lunar Atmosphere and Dust Environment Explorer) is meant to give scientists more understanding about the atmosphere of Earth's lone natural satellite.

This Week, @NASA Goes to Probe the #Moon with @NASALADEE. Join us Friday Night at 11:27pm ET https://t.co/Y1t0PTg0un pic.twitter.com/vWvGa4kxas

— NASA (@NASA) September 3, 2013

"Yes, the moon does have an atmosphere; it's just more tenuous than ours," said project scientist Richard Elphic, as quoted in the 'ScienceCasts: NASA Mission Seeks Lunar Air' video.  He added, "The moon's atmosphere is so flimsy, about 10 trillion times less dense than Earth that a good sneeze would rip through it like a hurricane."    

NASA had explained it in its website:

NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE, pronounced like "laddie") is a robotic mission that will orbit the moon to gather detailed information about the lunar atmosphere, conditions near the surface and environmental influences on lunar dust. A thorough understanding of these characteristics will address long-standing unknowns, and help scientists understand other planetary bodies as well.

There will be five phases to the LADEE's mission, namely: Launch, Ascent, Activation and Checkout, Phasing Orbits, Lunar Orbit Insertion, Commissioning, Science, and Decommissioning.

The Science Phase, fourth in the series, will last 100 days and, according to NASA, "is performed at an orbit that will vary between 20-60 kilometers due to the moon's 'lumpy' gravity field. During the Science Phase, the moon will rotate more than three times underneath the LADEE orbit.

The probe will carry instruments, among which is the Ultraviolet and Visible Light Spectrometer (UVS) which will analyze light signatures on different materials, thereby determining the composition of the atmosphere on the moon; and the Lunar Dust Experiment (LDX) which will collect and analyze lunar dust samples.

The mission is expected to last for approximately 160 days - 30 of which will be spent traveling to the moon, 100 days for science operations, and 30 days for checkout.