American space agency, NASA is planning to send a spacecraft past the Hartley 2 comet, which came close to Earth on Wednesday on its path.

Sky watchers were expecting the comet to brighten up to be seen by the naked eye when it zooms past Earth at a distance of just 11.2 million miles. However, the comet wasn’t bright enough and a pair of binoculars or telescopes was needed to get a decent view.

The Hartley 2, a pale green comet discovered on in 1986 by Australian astronomer Malcolm Hartley. It is an icy small solar system body which shows a visible temporary atmosphere and sometimes a tail when it comes nears the sun. Hartley 2 came closest to Earth than any other comet in the past century.

NASA's DIXI/EPOXI spacecraft is due to pass the comet within 450 miles from its nucleus. The space agency has planned to make a lot of observations from now until the day when the space craft will pass the comet.

The comet will next appear only around on April 20, 2017.