Juno completed a 35-minute engine burn that slowed the spacecraft so Jupiter’s gravitational pull could sweep it into an optimal orbit. After traveling billions of miles, Juno hurtled into an area of space just a few miles wide, aiming to hit that target within the span of a few seconds. So yeah, that’s a little tough.
At 10:30 p.m. Eastern time, NASA began broadcasting from mission control to document the Juno spacecraft’s insertion into an orbit around Jupiter. Although the video was live, the report wasn’t exactly in real time. The spacecraft’s signals take 48 minutes to travel 534 million miles to the Deep Space Network Antenna, in Goldstone, Calif.
At 11:18 p.m., the team announced that an engine burn designed to help the robot slip into an optimal orbit had started. Twenty minutes later, the team confirmed that the engine had burned long enough to enter some kind of orbit. But they needed to wait for the entire burn to finish to be sure that Juno was in the cozy orbit that is expected to last 53 days.
That signal arrived just a few minutes before midnight. Cheers broke out across the mission’s two control centers, at NASA’s Jet Propulsion Lab in California and at the Lockheed Martin control room in Colorado. The last step was confirmed around 12:40 a.m., when the solar-powered Juno orbiter turned its panels back toward the sun. Now the spacecraft’s successful orbital insertion can be considered complete.
“NASA did it again,” principal investigator Scott Bolton of the Southwest Research Institute said during a press briefing early Tuesday. “It’s almost like a dream comes true … and now the fun begins. The science.”
Rick Nybakken, Juno’s project manager, jubilantly tore up the mission’s contingency plan in front of the crowd.
“Tonight in tones, Juno sang to us,” he said as the hoots and hollers died down. “And it was a song of perfection.”
For now, the Juno team has only those tones to work with. The signals give team members basic information, letting them know that important milestones have been met, but they don’t provide very detailed data. Project personnel believe that the spacecraft did everything it was supposed to do so far, but they have to wait a few days for more sophisticated data to be transmitted.
We’ve visited Jupiter before with probes, but Juno is special. This spacecraft is designed to fly closer than any man-made object has ever gotten to Jupiter, probing beneath its roiling cloud cover to unlock new secrets. And Jupiter is a fascinating world. It could even help explain Earth’s origins (read more about that here).
Juno doesn’t just have an interesting target — it’s a very interesting robot for its own sake. Jupiter has some of the most intense radiation in the solar system. In some areas, the electrons surrounding it move nearly at the speed of light. That would tear your average robot’s computer to shreds, but Juno is encased in a unique suit of armor to protect it.
The robot’s scientific instruments were turned off several days ago to prepare for the orbital insertion, but they’ll be switched back on this week. The first real data is expected to arrive in late August.
Correction: An earlier version of this post compared Juno to a football field, when in fact it is the size of a basketball court. We're bad at sports.