Part of the difficulty of studying asteroids is that they just won't keep still. NASA's current dawn mission to study Vesta, for instance, has taken eight years so far and cost $360 million even before it launched.
But three scientists at Tsinghua University believe they have a solution - parking an asteroid in Earth orbit so that it can be studied at leisure.
The team figured that near Earth objects that weren't traveling too fast could be captured by Earth, possibly without any intervention.
"Its orbit would thereby be changed, and it would become an Earth-orbiting object after a small increase in its velocity," they say.
After examining 6,000 potential candidates, they say that there's no sign of any asteroids entering Earth orbit by themselves. But, they say, there are a number of candidates that would only need the smallest of nudges.
The best of these is a 10-meter-long object called 2008EA9, which will pass within a million kilometres or so of Earth in 2049, and which has a very similar orbital velocity to Earth's.
All it would take, says the team, is to change the object's velocity by 410 metres per second to shunt it into an orbit around the earth at about twice the distance of the moon.
Here, they reckon, it would maintain a stable orbit for a few yeears, during which it could be studied and even mined.