NASA spacecraft to perform final pass of Saturn's bizarre spongy moon
On听Sunday, May 31, the Cassini spacecraft will perform its last close pass of Hyperion, Saturn鈥檚 curiously听spongelike moon. At approximately 9:36 a.m. EDT (13:36 UTC) it听will zip听past Hyperion听at a distance of about 21,000 miles (34,000 km) 鈥� not its closest approach ever but considerably closer (by 17,500 miles/28,160 km) than it was when the听image above was acquired.*
This will be Cassini鈥檚 last visit of听Hyperion. It will make several flybys of other moons within Saturn鈥檚 equatorial plane over the course of 2015 before shifting to a more inclined orbit in preparation of the end phase of its mission and its operating life in 2017.
At 255 x 163 x 137 miles (410 x 262 x 220 km) in diameter, Hyperion is the largest of Saturn鈥檚 irregularly-shaped moons. Researchers听suspect听it鈥檚 the remnant听of a larger body that was blown apart by an impact. Hyperion鈥檚 craters appear to have a 鈥減unched-in鈥� look rather than having been excavated, and have no visible ejecta or secondary craters nearby.
Hyperion orbits Saturn in an eccentric orbit at a distance of over 920,000 miles (1.48 million km)鈥hat鈥檚 almost four times the distance our Moon is from us! This听distance 鈥� as well as constant gravitational nudges from Titan 鈥� prevents Hyperion from becoming tidally locked with Saturn like nearly all of its听other moons are. In fact its rotation is more of haphazard tumble than a stately spin, making targeted observations of any particular regions on its surface virtually听impossible.
Images from the May 31 flyby are expected to arrive on Earth 24 to 48 hours later.
As small as it is Hyperion is Saturn鈥檚 eighth-largest moon, although it appears to be very porous and has a density half that of water.听听and see more images of it from Cassini听听补苍诲听.
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*Cassini did come within 310 miles (500 km) of Hyperion on Sept. 26, 2005, but the images to make up the view above were听acquired during approach.
A graphic designer in Rhode Island,听听writes about space exploration on his blog听, Discovery News, and . Ad astra!
Originally published on听
