After five years hurtling through space, NASA’s Juno probe slipped into orbit around Jupiter, the biggest, oldest planet in our cosmic neighborhood, on the Fourth of July. As the world awoke Tuesday, scientists were abuzz with the possibility that the basketball-court-size spacecraft would help us understand how our solar system and all its planets and even life itself came to be.

The orbiter was traveling some 125,000 mph as it closed in on the king of the planets. It was aiming for an area of space just a few miles wide, trying to hit that target within the span of a few seconds. If it missed, the probe might have zipped right past Jupiter, burned up in the gas giant’s atmosphere or set itself on an orbital trajectory where the planet’s intense radiation would destroy the spacecraft’s instruments.

Scientists at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., sat crowded around computer screens, anxiously waiting to hear a few musical tones. The spacecraft’s instruments had mostly been shut off in preparation for the engine burn that would slow it down enough for a close encounter with Jupiter. Juno was programmed to send home a simple series of 10-second signals to let mission control know it had succeeded.

At 534 million miles away from Earth, Juno communicated with its creators with an agonizing 48-minute delay. Scientists didn’t even know the 35-minute burn had started as planned until 13 minutes after it finished. Just before midnight, they heard the tones they were waiting for: The engine burn had succeeded. Juno entered its orbit within one centimeter of the target, just one second later than the moment NASA had aimed for.

“NASA did it again,” principal investigator Scott Bolton of the Southwest Research Institute said during a news briefing early Tuesday. “It’s almost like a dream come true. … and now the fun begins. The science.”

The scene at NASA after spacecraft Juno entered the orbit of Jupiter.

Source: Why scientists are so excited about the Juno probe that is finally orbiting Jupiter – The Washington Post