http://messenger.jhuapl.edu/press_release_6_05_03.html

MESSENGER Puts on a MASCS

With several bolts and a few adjustments, MESSENGER team members at the Johns Hopkins Applied Physics Laboratory (APL) reached a milestone last weekend when they installed the first science instrument on NASA's Mercury-bound spacecraft.

On a busy May 31 in the APL cleanroom facilities in Laurel, Md., technicians attached the Mercury Atmospheric and Surface Composition Spectrometer (MASCS) onto the lower part of the spacecraft's structure, inside its Launch Vehicle Adapter ring. At about 12 inches long, 7 inches tall and 7 inches wide, the 5.5-pound MASCS was designed and built at the Laboratory for Atmospheric and Space Physics, University of Colorado at Boulder. The instrument will measure gases in Mercury's atmosphere and detect the minerals on the planet's surface.

Engineers also attached the main electronics unit for MESSENGER's Magnetometer; the first of the dual Data Processing Units (DPUs), which will control the science instruments and feed their data to the spacecraft; and the frame for MESSENGER's signature sunshade.

"This is a big step in MESSENGER's development," says Dr. Rob Gold, MESSENGER payload manager at APL. "From the team members who design the instruments to the people on the ground who install them, there's a great feeling that comes with getting that first part of the science payload on the spacecraft. Now we have six more instruments to go, and we expect things to come together rather quickly."

Later this week the team is scheduled to connect the DPU and MASCS to the spacecraft's main electrical system and install the X-Ray Spectrometer instrument. Gold adds that all the instruments are scheduled for integration on the spacecraft by mid-July.