As news spread worldwide of the arrival of Comet C/2013 A1 Siding Spring, anticipated to arrive yesterday Sunday Oct. 19 just outside of Mars' outer atmosphere, it appears that aerospace agencies invested in the red planet headed the warnings and got out of the way of the fast moving rock. Following NASA's lead in safety protocol, intended to keep Mars orbiters functional and safe from cosmic debris, other agencies like the European Space Agency (ESA) elected to "duck and cover" behind the planet Mars and peak out only for an up-close look at the rare, passing comet.
Alongside NASA's three orbiting Mars spacecrafts (the Mars Odyssey, the Mars Reconnaissance Orbiter and the Mars Atmosphere and Volatile Evolution Orbiter), the ESA's Mars Express and India's Mangalyaan spacecrafts also avoided near-collision with comet Siding Spring, who passed by Mars going at a speed of over 125,000 miles per hour. And at speeds of that proportion, researchers suggest that Mars orbiters were rather lucky that cometary dust did not interfere nor damage them in the process of capturing the rare event.
"All it takes is a little tiny grain of sand traveling at that speed and you've got damage to solar arrays, or your propulsion line or critical wires" team leader of NASA's MAVEN mission to Mars, Nick Schneider says.
Named after the Australian Observatory where it was first discovered in January 2013, Siding Spring is largely composed of gas, ice and pebbles, with a loose density astronomers relate to that of talcum powder. Originating in the Oort Cloud on the fringes of our solar system, nearly 4.5 billion years ago, the rare comet is on its first pass around our sun since leaving the distant cometary cloud. And researchers believe that since it still has not shed all of its icy layers, typically burned away after repeated trips, that Siding Spring may give us insight into what conditions led to the creation of our solar system eons ago.
"Think about a comet that started its travel probably at the dawn of man and it's just coming in close now" senior astrophysicist at Johns Hopkins, Carey Lisse said in a NASA news briefing held last week. "And the reason we can actually observe it is because we have built satellites and rovers. We've now got outposts on Mars."
Capturing imaging, in a wide range of spectra, as well as composition analyses/estimates regarding the shape and makeup of the passing comet, the orbiters taking shelter behind Mars recorded the cosmic passing and will be delivering data back to Earth over the next few days. Though astronomers consider Siding Spring to be a relative newcomer on the cosmic block, researchers believe that its young age may give a clearer view to how our solar system came to be, and how close-passing comets interact with the outer atmospheres of planets.
"This is a cosmic science gift that could potentially keep on giving, and the agency's diverse science missions will be in full receive mode" astronaut for NASA's Science Mission Directorate, John Grunsfeld says. "This particular comet has never before entered the inner solar system, so it will provide a fresh source of clues to our solar system's earliest days."
