National Aeronautics and Space Administration Logo
Follow this link to skip to the main content NASA Banner
Solar System Exploration
News & Events
MESSENGER On Deck
MESSENGER On Deck
2 Jul 2004
(Source: Johns Hopkins University Applied Physics Laboratory)

http://messenger.jhuapl.edu/webcam/annotatedimages/annotated- 20040702.html

MESSENGER Mission News July 2, 2004

Upon Reflection . . .

MESSENGER will rely on solar panels for power during its long voyage to and orbit around Mercury. The custom-developed panels, installed on the spacecraft June 24-25, were the next-to-last major components to be attached before the spacecraft is moved to the Delta II launch vehicle this month. This week's annotated Webcam image captures the installation in progress.

To run MESSENGER's systems and charge its 23-ampere-hour nickel- hydrogen battery, the panels, each about 1.5 meters (5 feet) by 1.65 meters (5.5 feet), will support between 385-485 watts of spacecraft load power during the cruise to Mercury and 640 watts during the science orbit. The panels could produce more than two kilowatts of power near Mercury, but to prevent stress on MESSENGER's electronics, onboard power processors take in only what the spacecraft actually needs.

The panels are 67 percent mirrors (called optical solar reflectors) and 33 percent triple-junction solar cells, which convert 28 percent of the sunlight hitting them into electricity. Each panel has two rows of mirrors for every row of cells; a total of 648 cells and 1,296 mirrors per panel. The small mirrors reflect the Sun's energy and keep the panel cooler. The panels also rotate, so MESSENGER's flight computer will tilt the panels away from the Sun, positioning them to get the required power while maintaining a normal surface operating temperature of about 150 degrees Celsius, or 302 degrees Fahrenheit.

Major events before moving the spacecraft include fueling - the team is loading the hydrazine fuel and nitrogen tetroxide oxidizer this week - and final installation of the sunshade.

News Archive Search  Go!
Show  results per page
 
 
Awards and Recognition   Solar System Exploration Roadmap   Contact Us   Site Map   Print This Page
NASA Official: Kristen Erickson
Advisory: Dr. James Green, Director of Planetary Science
Outreach Manager: Alice Wessen
Curator/Editor: Phil Davis
Science Writer: Autumn Burdick
Producer: Greg Baerg
Webmaster: David Martin
> NASA Science Mission Directorate
> Budgets, Strategic Plans and Accountability Reports
> Equal Employment Opportunity Data
   Posted Pursuant to the No Fear Act
> Information-Dissemination Policies and Inventories
> Freedom of Information Act
> Privacy Policy & Important Notices
> Inspector General Hotline
> Office of the Inspector General
> NASA Communications Policy
> USA.gov
> ExpectMore.gov
> NASA Advisory Council
> Open Government at NASA
Last Updated: 7 Jul 2004