Discovered last year by Robert H. McNaught at Siding Spring Observatory in New South Wales, Australia, the comet named 'Siding Spring' is moving towards the Sun along around one-million year orbit and is now within the radius of Jupiter's orbit. "This is critical information that we need to determine whether, and to what degree, dust grains in the coma of the comet will impact the Mars and spacecraft in the vicinity of the planet," said Jian-Yang Li of the Planetary Science Institute in Tucson, Arizona in the US.
The comet would also be closest to the Sun Oct 25, 2014, at a distance of 130 million miles or 208 million km, quite outside of the Earth's orbit. The comet, however, would not likely to be seen with the naked eye.
Astronomers were keen on getting images when the Earth crossed the comet's orbital plane, the path the comet takes as it orbits the Sun. The Hubble Space Telescope also observed 'Siding Spring' Jan 21 when the Earth was crossing its orbital plane. This positioning of the two bodies allowed astronomers to determine the speed of the dust coming off the nucleus.
The Hubble is a project of international cooperation between the NASA and the European Space Agency.