NASA collected an asteroid sample. But some of it is leaking into space

The historic collection of a sample from the near-Earth asteroid Bennu by NASA's OSIRIS-REx spacecraft has become a victim of its own success.

The US probe that collected a sample from the asteroid earlier this week retrieved so much material that a rock is wedged in the container door, allowing rocks to spill back out into space, NASA officials said on Friday.

The robotic arm of the probe, OSIRIS-REx, on Tuesday night kicked up a debris cloud of rocks on Bennu, a skyscraper-sized asteroid some 200 million miles (320 million km) from Earth and trapped the material in a collection device for the return to Earth.

But images of the spacecraft's collection head beamed back to ground control revealed it had caught more material than scientists anticipated and was spewing an excess of flaky asteroid rocks into space.

The leakage had the OSIRIS-REx mission team scrambling to stow the collection device to prevent additional spillage.

The team isn't sure of the exact loss rate because it's not steady.

If this continues, NASA will not know how much material it collected until the sample capsule returns in 2023. 

The roughly $800 million, minivan-sized OSIRIS-REx spacecraft, built by Lockheed Martin, launched in 2016 to grab and return the first US sample of pristine asteroid materials.

The spacecraft won't begin its journey back to Earth until March 2021