14 DAY TRIAL // Experts managing the EPOXI mission that flew past comet Hartley 2 a couple of weeks ago say that the spacecraft was hit at least nine times by icy debris originating from the space object. Regardless, the probe continued to snap and send back amazing images of the body's nucleus.
The flyby took the Deep Impact spacecraft very close to Hartley 2, at a distance of about 700 kilometers. This was well within the range of the snowstorm that covers the surface of the body, and which shields its nucleus from direct observations.
According to mission controllers, the probe did not suffer any significant damage following the collisions. The announcement was made Thursday, November 18. The experts also added that this flyby marked the first time a blizzard of water ice was found to exist around a cometary nucleus.
Such an event was never observed before, and researchers had no theory to state that it should exist. The discovery was only made possible due to the close distance EPOXI passed from the comet.
“When we first saw this, our mouths just dropped. To me, this whole thing looks like a snow globe that you've shaken,” explains to reporters Brown University scientist and flyby team member, Pete Schultz.
An interesting discovery was that the snowstorm appeared to be fueled by jets of carbon dioxide, which is something that researchers did not notice in any other comet before. Similar bodies are usually fueled by water vapor.
Images revealed that some of the ice particles surrounding Hartley 2's nucleus are diminutive, whereas others are larger than the average hailstone back on our planet. However, the comet's ices are apparently very fluffy, as they are basically aggregates made of tiny snow crystals.
“The biggest ones are at least the size of a golf ball, and possibly as big as a basketball,” explains University of Maryland scientist Mike A'Hearn, who is also the principal investigator of the new mission, Space reports.
The fluffiness of the comet's ices is probably the main reason why the Deep Impact space probe did not suffer any extensive damage following the collisions. The spacecraft was traveling at 27,000 miles per hour (43,450 kph).
At speeds such as this, even the smallest object can put a serious dent in the thickest armor. However, the density and structure of the snow flakes prevented the $252 million EPOXI spacecraft from suffering any permanent damage.
One of the main things that this flyby proved was that most comets are indeed different from each other, and that each of them needs to be studied as an individual. Some of their particularities could be used to gain more insight into the origin of life on Earth, or into the early history of the solar system.
Hartley 2 aided this effort three times. It visited the comet Tempel 1 in 2005, comet Boethin in 2008, and comet Hartley 2 in 2010.