The LADEE lunar atmospheric probe has returned its first views of the moon's surface as it enters the second half of its research mission, NASA announced last week.

This series of LADEE star tracker images features the lunar terrain. Credit: NASA Ames
 
The lightweight spacecraft has been orbiting the moon since early October, and it does not carry conventional cameras to collect views of the lunar surface. But like many satellites, LADEE is equipped with star trackers, a special type of imager to help the probe navigate in space.

The Lunar Atmosphere and Dust Environment Explorer, or LADEE, spacecraft has been in orbit around the moon since October. The $280 million mission launched in September to investigate the tenuous lunar atmosphere, a nebulous collection of atoms and molecules enveloping the moon.

LADEE's star trackers sometimes catch glimpses of the lunar surface amid their usual duties of locating the positions of a catalog of bright stars. The position data are fed into the craft's navigation system to determine LADEE's orientation as it flies around the moon.

The observatory sent home its first such images of the moon earlier this month. The series of five images were taken at one-minute intervals, according to NASA, showing a region in the northwestern hemisphere of the moon.

The images were taken during the lunar night, but the sensitive star trackers picked up enough light from Earthshine to see features such as craters and mountain ranges.

NASA says LADEE took the images Feb. 8 as it was collecting atmospheric measurements. LADEE's current orbit ranges in altitude from 8 miles to 37 miles above the moon.

Artist's concept of LADEE. Credit: NASA/Dana Berry
 
"Star tracker cameras are actually not very good at taking ordinary images," said Butler Hine, LADEE project manager at NASA's Ames Research Center in Moffett Field, Calif. "But they can sometimes provide exciting glimpses of the lunar terrain."

A NASA press release describes the lunar surface features visible in the images:

• The first image captured the smooth-floored crater Krieger, about 14 miles (23 km) in diameter, on the horizon, with four mile (seven km) wide Toscanelli, in the foreground.
  
  
• The second image shows Wollaston P, about two-and-a-half miles (4 km) diameter, near the horizon, and the southeastern flank of the lunar mountain Mons Herodotus.
  
  
• The third image caught a minor lunar mountain range, Montes Agricola, which is northwest of the large bright crater Aristarchus (out of view), as well as the flat-floored crater Raman, about six miles (10 km) diameter.
  
  
• The fourth image in the series captures Golgi, about four miles (6 km) in diameter, and three-mile-wide (5 km) Zinner.
  
  
• The final image views craters Lichtenberg A and Schiaparelli E in the smooth mare basalt plains of Western Oceanus Procellarum, west of the Aristarchus plateau.

NASA announced a four-week extension of LADEE's mission in January to continue the probe's research mission until around April 21, when the spacecraft will strike the moon once it runs out of fuel.

The extra time will allow LADEE to fly closer to the moon. The mission's three instruments sample lunar dust particles and examine the chemical make-up and sources of molecules in the moon's ultra-thin atmosphere.

"The launch vehicle performance and orbit capture burns using LADEE's onboard engines were extremely accurate, so the spacecraft had significant propellant remaining to enable extra science," Hine said in a NASA press release. "This extension represents a tremendous increase in the amount of science data returned from the mission."

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