On June 13, 2010, a fireball streaked over the Australian outback as a 510-kilogram spacecraft burned up on purpose while a small capsule parachuted to the ground. Nobody knew for sure whether it held anything. This episode follows the Japanese Aerospace Exploration Agency’s Hayabusa mission, an underdog story of cascading failures and stubborn problem-solving on the way to asteroid Itokawa and back.

We explain why a Japanese rocket failure in 2000 forced a change of target, how a record solar flare in 2003 damaged the solar cells and starved the xenon ion engines, and how two reaction wheels failed before arrival. At the rubble-pile asteroid, the Minerva mini-lander drifted into space, two touchdown attempts went wrong, and a tiny fuel leak sent the probe tumbling and silent. We describe how engineers waited for precession to stabilize the spin, vented xenon to regain control, and finally cross-wired two broken ion engines into one working unit to get home. Then we look at the 1,500 microscopic grains found in the capsule and why they finally linked S-type asteroids to ordinary chondrite meteorites.

• Why missing a launch window means the asteroid is no longer where you need it
• Ion engines with the thrust of a sheet of paper and why they need constant solar power
• Why a wheeled rover would launch itself off an asteroid with tiny gravity
• The 25 g reentry and the nitrogen clean room where the capsule was opened
• Why pristine dust beats meteorites already found on Earth