Flyby puts Juno spacecraft on a course for Jupiter

[rhoenix]

Online observatory Slooh has streamed live pictures of NASA’s Juno space probe flyby. The feed from the robotic half-meter telescope in the Canary islands gave visitors a ringside seat as the probe passed within 347 mi (559 km) of Earth in a slingshot maneuver designed to take it all the way to Jupiter.

The Juno space probe was launched in 2011 and since then has been carrying out a series of orbital maneuvers to give it enough speed to reach the planet Jupiter, where it will go into orbit as part of a mission to learn more about the structure and nature of the deep atmosphere of the giant planet.

Having traveled out beyond the orbit of Mars, Juno returned to Earth for a flyby this week. In an interview with Stephen Cox of Slooh that accompanied the live feed, JPL scientist Steven Levin, speaking from mission control in Denver, explained how this worked.

“We could not afford a big enough rocket to launch Juno with enough energy, enough speed to get all the way to Jupiter," said Cox. "So, we’re using a technique called gravity assist … The basic idea is to latch onto an object and use its gravity to give it a boost. It’s a bit like coming up to a truck on the highway and grabbing onto the truck for a bit to get extra speed.”



On Wednesday at 3:21 PM EDT, the unmanned, US$1.1 billion Juno probe passed within 347 mi (559 km) of Earth as it hurtled over South Africa. For 20 minutes, the spacecraft was in the shadow of the Earth, which is the only time during the mission when it drew no power from the massive solar panels designed to work while in orbit around Jupiter, which lies five times the distance of the Earth from the Sun.

In Wednesday’s interview, Dr Levin explained that NASA provided no press releases or any other information on the flyby because of the partial shutdown of the US government due to budget disputes. “The good news is that because of the nature of what we were doing, we were granted an exception to the shutdown, so the people who were necessary to make sure that the spacecraft was safe and we collected the data we need to collect, and so forth were all allowed to keep working.

"The bad news from the point of view of the government shutdown is that anything to do with press releases and sending the information out to the public and so forth is not part of what’s considered essential activity that’s granted that exception. All of NASA’s usual procedures for seeing what we’re doing shut down and the word’s getting out a little bit through avenues like this and people who work with us, but the real release ‘here’s everything we did’ will have to wait until the government is operating again.”

The only apparent hitch on Wednesday came as Juno completed the slingshot maneuver. NBC News reports that when Juno came out of the Earth’s shadow, it was in safe mode, indicating that it had encountered some sort of malfunction. The craft is en route to Jupiter as scheduled while NASA engineers try to determine the cause.

The video below shows some of the image feed from the Canary Islands as Juno flew by.

Video: [youtube][/youtube]

NASA's still doing cool stuff.

[rhoenix]

Bill Nye is back. He is back with a purple lab coat, a spotted bow tie, and serious, levelheaded science packaged in zaniness.

Mr. Nye, now the CEO of the Planetary Society, has launched a new miniseries on YouTube called "Why With Nye” that covers the Juno mission to Jupiter. The series debuted online on Tuesday, with an episode explaining the Juno’s Earth pass-by, expected a day later.

“Why With Nye features legendary educator and entertainer Bill Nye demystifying the cutting-edge science behind NASA's groundbreaking Juno mission to Jupiter,” according to the THNKR channel, where the series is hosted.

Nye, a former mechanical engineer at Boeing, was the host of “Bill Nye the Science Guy” from 1992 to 1996. Since then, he has emerged as a public defender of science, a bulwark against efforts to put creationism in schools and the idea that climate change is not happening. And even after giving up the “Science Guy” mantle, he has remained a popular educator and entertainer with a gift for explaining complicated science with a dose of goofiness.

“For centuries, we studied the planet Jupiter with instruments like this,” says Nye, holding an old, wooden telescope. “But if you’re like me, and I know I am, you want to know more. And in order to know more, we’ve got to get a spacecraft up close. But Jupiter is fantastically far away – way out there. So how do we do it?”

Well, we – or rather, NASA – build the Juno spacecraft.

Juno was launched in 2011 with an Atlas V 551 rocket – “Like everything else the government does, we were on a budget, so we had to use a rocket that already existed,” says Nye, cryptically. At about noon on Wednesday, the craft, drifting back toward Earth from Mars’s orbit, picked up a gravity boost from its home planet to help send it toward Jupiter, some 483 million miles from Earth. It is expected to arrive at the gas giant in 2016.

Unexpectedly, the craft is now in “safe mode,” the protective state into which a spacecraft goes when it encounters a problem, the Planetary Society reported. Though it is unclear what caused the craft to defend itself, it is reported to be secure.

But we may have to wait a while for Nye himself to reassure us that the craft is OK. Following the mothballing of most of NASA’s activities during the government shutdown, Nye’s program is now suspended.

“This just in: our gov’t is shut down,” he tweeted, on Wednesday. “So no hangout today, unfortunately.”

“Don’t think Juno spacecraft will change course as a result,” he said.

For the series Why with Nye: [youtube][/youtube]

[rhoenix]

More Juno amusement:

A mystery that has stumped scientists for decades might be one step closer to solution after ESA tracking stations carefully record signals from NASA's Juno spacecraft as it swings by Earth today.



NASA's deep-space probe will zip past to within 561 km at 19:21 GMT as it picks up a gravitational speed boost to help it reach Jupiter in 2016.

During the high-speed event, radio signals from the 2870 kg Juno will be carefully recorded by ESA tracking stations in Argentina and Australia.

Engineers hope that the new measurements will unravel the decades-old 'flyby anomaly' -- an unexplained variation in spacecraft speeds detected during some swingbys.

"We detected the flyby anomaly during Rosetta's first Earth visit in March 2005," says Trevor Morley, flight dynamics expert at ESA's ESOC operations centre in Darmstadt, Germany.

"Frustratingly, no anomaly was seen during Rosetta's subsequent Earth flybys in 2007 and 2011. This is a real cosmic mystery that no one has yet figured out."

Sometimes there, sometimes not

Since 1990, mission controllers at ESA and NASA have noticed that their spacecraft sometimes experience a strange variation in the amount of orbital energy they pick up from Earth during flybys, a technique routinely used to fling satellites deep into our Solar System.

The unexplained variation is noticed as a tiny difference in the expected speed gained (or lost) during the passage.

The variations are extremely small: NASA's Jupiter probe ended up just 3.9 mm/s faster than expected when it swung past Earth in December 1990.

The largest variation- a boost of 13.0 mm/s -- was seen with NASA's NEAR asteroid craft in January 1998. Conversely, the differences during swingbys of NASA's Cassini in 1999 and Messenger in 2005 were so small that they could not be confirmed.

The experts are stumped.

ESA stations listen for Juno

On 9 October, engineers and the flight dynamics teams at ESOC will watch closely as the Agency's new 35 m-diameter deep-space dish in Malargüe, Argentina, and a smaller 15 m dish in Perth, Australia, track Juno starting at about 16:00 GMT.

The stations will record highly precise radio-signal information that will indicate whether Juno speeds up or slows down more or less than predicted by current theories.

The results will be studied closely by ESA and NASA as well as scientists worldwide, who are hoping to see whether the anomaly is again detected.

"Our Malargüe station is designed to track very distant and relatively slow-moving spacecraft, while Juno will pass by moving very, very fast at just 561 km altitude," says ESA's Daniel Firre, responsible for the tracking support at ESOC.

"This makes tracking Juno technically very challenging, but it's how the scientific process works. Gathering more data that can be analysed by experts is critical if we are ever to solve this perplexing mystery."

This is NASA going "lol wtf Juno?"

Also, it raises the strong question that maybe probes have been doing this the whole time we've been sending up probes, and we just haven't been able to detect the minute variations anywhere near as well until now.