Sponge in space

Hyperion

On August 25 Cassini did a close fly-by of the small Saturn moon Hyperion, getting as close as 15,500 miles. The mission has just released images from that fly-by.

Looks like a sponge, doesn’t it? This moon is small, only 168 miles across, which makes it about half the size of the asteroid Vesta that Dawn is presently orbiting. Why it is so peppered with craters is of course the big science question. I would guess this has something to do with the environment around Saturn, with its rings and the innumerable particles that come from it. Yet, other moons of Saturn are not as crater-filled, so there is obviously more to this than meets the eye.

This fly-by was the second closest of Hyperion that Cassini has done, the first passing over the the moon’s surface by only 310 miles. Because the irregularly-shaped moon’s rotation is more like a chaotic tumble, scientists could not predict what part of the surface they would see. To their luck the new images captured new territory.

Another fly-by is scheduled in only three weeks, on September 16, 2011. This time, however, the spacecraft won’t get as close, passing at a distance of about 36,000 miles.

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When dust, pebbles, rocks, and boulders act like liquid

The science team of Lunar Reconnaissance Orbiter released an intriguing picture yesterday of what scientists call a granular flow down the side of a five mile wide crater on the far side of the moon. Looking at the image, one would swear that the darker material flowing down the slope of the crater rim is a lava flow frozen in place.

lunar granular flow

However, according to the scientists, that is not what it is. Instead, this is merely debris left behind from an avalanche.
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Capturing an asteroid into Earth orbit

orbital path after asteroid capture

Want to mine an asteroid? Rather than travel to it with all their mining equipment, three Chinese scientists have proposed a better way. In a paper published today on the Los Alamos astro-ph preprint website, they have calculated the energy required to shift the orbits of the six thousand near-Earth asteroids and place them in Earth orbit for later mining. Of these, they found 46 asteroids that had the potential for such an operation, and two likely candidates for a space mission. One 30-foot-wide asteroid, 2008EA9, will actually be in the right place for this technique in 2049. As they write,

It can be seen that the velocity increment of the 2008EA9 is relatively small (-1.00km/s) and it will very close approach [approximately 645,000 miles] to the Earth in [February] 2049. Moreover the size of the NEO 2008EA9 is very small so that the capturing of it is relatively easy.

The real problem, of course, is adding that small “velocity increment” to the asteroid.
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Progress freighter launch fails

The launch of a Progress freighter to ISS today has failed, with the freighter ending up crashing into Siberia.

This is very bad news for the station. Everyone in the space industry knows that with the shuttle gone, it will be a challenge to maintain supplies to the station’s the six-person crew. Losing just one supply ship will strain the station’s supplies, if not now in the long run for sure.

Worse, this is the first launch failure of the Soyuz rocket that puts both Progress and manned Soyuz capsule into orbit in more than eleven years. The next manned crew is scheduled for launch on September 21. Whether this failure will delay that launch remains unknown.

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