It’s been nine years and 4.8 billion kilometers coming, but NASA’s New Horizons spacecraft is about to realize its destiny. In just four weeks, it will begin its historic flyby of the former planet after a small directional adjustment by NASA engineers.
Aiming for the original target about 7,750 miles above Pluto’s surface, the 45-second thruster burst performed Sunday was only the second intervention in New Horizons’ nine year space odyssey. The next opportunity to adjust course will come on June 24, and engineers may need it – New Horizons’ journey will take it into the orbit of all five of Pluto’s moons, and NASA is essentially threading a needle to get it safely in range.
“Every day we break a new distance record to Pluto, and every day our data get better,” says mission Principal Investigator Alan Stern, of the Southwest Research Institute, Boulder, Colorado. “Nothing like this kind of frontier, outer solar system exploration has happened since Voyager 2 was at Neptune way back in 1989. It’s exciting–come and watch as New Horizons turns points of light into a newly explored planetary system and its moons!”
NASA is constantly searching for obstacles as New Horizons moves into the Pluto system, which is expected to happen on July 14. So far, they’ve detected the five moons, but no other hazards – no rings, and no smaller, previously unknown moons. In order to exist but escape detection, moons would have to be dimmer than Pluto’s smallest moon Styx but further than Charon, its largest and closest moon. Ring systems would have to be similarly slight, less than 1,000 miles wide or reflecting less than one 5-millionth of the incoming sunlight.
One week before the close approach, New Horizons is scheduled to enter Approach Phase 3. Expect some stunning images as the craft takes detailed photos and does one last sweep of the system for hazards and unseen object.