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Study of Recent Interstellar Asteroid Reveals Bizarre Shape (bbc.com)
JoeRobe writes: A few weeks ago an interstellar asteroid, now named "Oumuamua," was discovered passing through our solar system. Being the first interstellar asteroid to ever be observed, a flurry of observations soon followed. This week, an accelerated article in Nature reveals that Oumuamua is more bizarre than originally thought: it is elongated, with a 10:1 aspect ratio, and rapidly rotating. This conclusion is based upon comparisons of its time-dependent light curve to those from 20,000 known asteroids.
In order to land on such an asteroid rather than be smashed into a trillion pieces by it, you have to match the speed of the asteroid. At that point, you can already go wherever the asteroid is going -- or lots of better places -- just as quickly without landing on it. How is that a shortcut? Seems to make the whole process immensely more complicated and fuel-consuming than just going from point A to point B.
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Only the maximum and minimum moments of inertia are stable in rotation. If you try to spin an object around any other axis, it will tumble - the axis of rotation varies relative to the body. Every spacecraft or satellite that's launched had some poor slob whose job was to get the exact mass, location, and inertia tensor of every single component put into the spacecraft, and put it into a huge spreadsheet. Then he uses that to calculate the minimum and maximum moments of inertia of the spacecraft. If the desired spin axis doesn't line up with either of these moments, then he has to change the location of some of the components of the spacecraft until it does (like positioning weights on a tire when you balance it)..
With round or nearly round objects, the min/max moment of inertia isn't very different from from the inertia around other axes, so this oscillation tends to be very slow and not noticeable. But it's much more likely to be pronounced with an elongated and flattened body.