Pioneer 10NASA launches Pioneer 10, the first spacecraft sent to study the huge planet Jupiter at close range. Its Atlas-Centaur booster gives it a good head start, propelling it to over 32,000 miles per hour en route to Jupiter, the fastest man-made object in history at this point. Pioneer 10 is also the first man-made vehicle to traverse the asteroid belt, with instruments detecting fewer large particles than anticipated. It will reach Jupiter in late 1973.