FollowMore than 12 years have passed since NASA’s Mercury-orbiting spacecraft, MESSENGER, was sent to gather information on the planet closest to the sun. MESSENGER is running on its last few fuel reserves and NASA has made the choice to purposely crash the probe into the surface of the planet it was designed to study, later this week, on April 30th (Thursday).
The spacecraft run out of actual fuel for its thrusters a little while ago, but ground controllers managed to extend its life by tapping into helium gas reserves. It is expected to travel at 8,750 mph (14,081 kph) when it hits the rocky surface and leave a visible mark on the planet upon impact. It will crash into the side of Mercury facing away from the Earth, unable to be seen or documented by scientist.
The team behind MESSENGER was emotional, and slightly taken by surprise at the passing of the time, going on their Twitter to share a few thoughts: “I guess the end is coming…After ten years, spacecraft will end life as just another crater on Mercury’s surface”.
Launched from Cape Canaveral on August 3, 2004 and powered by two body-mounted gallium arsenide solar panels and a nickel-hydrogen battery, MESSENGER (MErcury Surface, Space ENvironment, GEochemistry and Ranging) weighs 507.9kg (1,100 pounds), is 1.42m tall, 1.85m (4,65 feet) wide, 1.27m (4,16 feet) deep, and is the first spacecraft to ever circle Mercury.
The NASA probe flew twice past Venus and 3 times past Mercury, before finally entering orbit around Mercury on March 18, 2011 and enjoying a highly successful four-year tour of the planet.
Set at just 57.9 million km from the sun, the small planet Mercury has proven to be a world of wonders with drastic temperature swings (800 degrees Fahrenheit during the day and minus 300 degrees at night), volcanic deposits, shallow, enigmatic depressions on its surface, ice craters at poles and signs that is has shrunk slightly as it cooled over billions of years.
Sean C. Solomon, the mission’s principal investigator and director of Columbia University’s Lamont-Doherty Earth Observatory, declared that “It’s really been exciting to see a planet unfold, a planet that is one is our neighbors. Almost every aspect of Mercury has had its share of surprises”. He believes that planetary scientists will be looking at data gathered by MESSENGER “for years, probably for decades, as we try to understand the origin and evolution of Mercury,”
One thing that hasn’t been a surprise however is the discovery of the ice craters. Telescope observations were indicative of cold, reflective objects, though MESSENGER din reveal a new piece of information – the ice is covered by a yet to be explained dark layer.
Doctor Sean Solomon theorizes that the dark layer might be compiled of carbon-rich compounds similar to those found in meteorites and comets: “It’s tarlike in its consistency” and “It’s as dark as tar”.
The biggest discovery remains Mercury’s rich, generous supply of volatile elements that evaporate and help moderate temperatures – chlorine, sulfur, potassium and sodium.
Image Source: nbcnews.com
