The first spacecraft to orbit Mercury has been honored with a United States Postal Service "forever" stamp, issued on May 4, 2011. Credit: U.S. Postal Service
- Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
NASA’s MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft circling the planet Mercury has chalked up its 100th orbit. That milestone was achieved on May 6th with the probe executing nearly 2 million commands since it swung into orbit on March 17th.
“We are building up the first comprehensive view of the innermost planet,” states MESSENGER Principal Investigator Sean Solomon of the Carnegie Institution of Washington.
The NASA-sponsored scientific investigation of the planet Mercury is the first space mission designed to orbit the planet closest to the Sun.
“The surface is unraveling before our eyes in great detail,” Solomon added, “and the planet’s topography and gravity and magnetic fields are being steadily filled in. As the Sun becomes increasingly active, Mercury’s extraordinarily dynamic exosphere and magnetosphere continue to display novel phenomena.”
The data gathered so far include more than 70 million magnetic field measurements, 300,000 visible and infrared spectra of the surface, 16,000 images, and 12,000 X-ray and 9,000 gamma-ray spectra probing the elemental composition of Mercury’s uppermost crust.
But the real “hot” news from MESSENGER is that the spacecraft will see sweltering temperatures over the next several weeks.
“MESSENGER’s subsystems and instruments will experience their hottest temperatures yet as the spacecraft crosses between the planet’s surface and our Sun at high noon close to the planet, preceded by hour-long eclipses near local midnight with only the spacecraft battery to keep the spacecraft alive in the dark of Mercury’s night,” notes MESSENGER Project Scientist Ralph McNutt.
The Johns Hopkins University Applied Physics Laboratory built and operates the MESSENGER spacecraft and manages this Discovery-class mission for NASA.
By Leonard David