What Jupiter’s spot is not, is tranquil. New infrared images taken by Boston University scientists on a NASA telescope in Hawaii show that whereas Jupiter’s north and south poles are heated by strong magnetic fields, its large, stormy red spot generates its own heat by a different mechanism. Shock waves from turbulent winds in the spot and other storms help explain how the planet’s upper atmosphere stays warm so far from the sun. Read the rest of this entry »
Loren Grush reports: NASA’s Juno spacecraft has successfully entered Jupiter’s orbit, bringing it closer to the planet than any probe has come so far. The vehicle reached the gas giant’s north pole this evening, and NASA received confirmation that the vehicle had turned on its main engine at 11:18PM ET. The engine burned for 35 minutes, helping to slow the spacecraft down enough so that it was captured by Jupiter’s gravitational pull. NASA confirmed that the burn was successful at around 11:53PM ET and that Juno was in its intended 53-day orbit.
— NASA (@NASA) July 5, 2016
The orbit insertion was a bit of a nail biter for NASA, as the spacecraft had to travel through regions of powerful radiation and rings of debris surrounding Jupiter. As an added precaution, the probe’s instruments were turned off for the maneuver so that nothing would interfere with the engine burn. But everything seemed to work flawlessly, and NASA received confirmation of the burn’s success almost exactly as expected. The timing only differed by 1 second from pre-burn predictions.
That confirmation came 48 minutes after the event actually occurred, though. That’s because it currently takes 48 minutes to send a signal from Jupiter to Earth. Juno started its burn at around 10:30PM ET and finished at 11:05PM ET, but NASA didn’t confirm all of this until just before midnight. If something had gone wrong and stopped the burn too early, the space agency wouldn’t have been in a position to fix the problem. Read the rest of this entry »
Jennifer Ouellette reports: NASA’s Juno spacecraft has been spinning through space on its way to Jupiter for five years and 445 million miles, and now it’s less than 10 hours away from entering the gas giant’s orbit—the equivalent of a single rotation of Jupiter. If all goes well, scientists will finally be able to learn what lies beneath Jupiter’s turbulent atmosphere, examine its impressive magnetosphere, and possibly determine the composition of its core.
“If Juno gets hit even by a small piece of dust, it can do a great bit of damage,” he said. “We believe probability is incredibly low that Juno will hit dust or debris, but it’s not zero. Even a 10 micron particle could do some damage moving at the speed we’re moving.”
— Juno project manager Scott Bolton
But first, it’s going to have to execute a tricky 35-minute engine burn under the harshest conditions any NASA spacecraft has yet faced. And that has Juno mission scientists on edge today. They’ve modeled every scenario they can think of, and planned for every contingency. But as Juno project manager Scott Bolton said in this morning’s briefing at the Jet Propulsion Laboratory in Pasadena, “This is the highest risk phase.”
“We’ve done everything humanly possible to make this mission a success, but it’s still a cliffhanger,” said Jim Green, director of planetary science at NASA headquarters in Washington, DC.
Thus far, the mission has gone off without a hitch, but plenty could still go wrong. For instance, what if the main engine doesn’t fire on cue to start the burn, so far from the sun? “We’ve fired the main engine twice successfully and the third time should be a charm,” said Rick Nybakken, Juno project manager. “But this is the first time we’ve ever fired the main engine at Jupiter. It’s make or break for us.”
Then there’s the intense radiation from Jupiter’s enormous magnetosphere. According to Heidi Becker, lead investigator for Juno’s radiation monitoring, this translates into millions of high energy electrons moving near the speed of light. “They will go right though the spacecraft,” she said. “It’s the equivalent of 100 million x-rays in less than a year for a human being if we had no protection.”
Juno’s polar orbit will avoid the worst of the radiation belts at the planet’s equator, but other high-intensity regions are unavoidable. Read the rest of this entry »