When Galileo First Traded Jupiter For A Quick Look At An Asteroid

Humanity had never seen an asteroid up close until a Jupiter-bound probe broke through the cosmic unknown in October 1991. The Galileo spacecraft swung past the inner edge of the asteroid belt to photograph Gaspra, marking the first time any mission visited an asteroid. Traveling at a relative speed of 5 miles per second, the probe passed 990 miles away from the irregular, elongated rock.

Because the spacecraft stayed too far away for gravity to pull it, scientists could not measure the asteroid's mass. Even so, onboard cameras and spectrometers mapped a cratered surface covered in a thin layer of dust and rubble, hinting at a violent past of catastrophic collisions. Our read is that this planetary pitstop quietly birthed modern asteroid science.

What began as a mere navigational milestone on a six-year trek to the largest planet in our solar system paved the way for future sample returns and planetary defense missions. Watch how deep space exploration continues to evolve from these early encounters as agencies hunt for clues to the solar system's history.