What were you doing at 0852 GMT (04:52 EDT) on Monday March 27th? I was just falling asleep for the first time. It was 2:52 AM Mountain. I don’t sleep much any more. Ryan was probably already awake and writing the show notes for the podcast. I am fairly certain Eloy was asleep as well. It’s a good bet Vigo was. What were you doing? Not many of us were thinking about Jupiter I’d bet. Yeah… the gas-giant. Juno was wide awake!
The Juno Mission
August 5th, 2011 – Cape Canaveral – An Atlas V 551 threw a small spacecraft called Juno into the skies. After an Earth fly-by in 2013 to get a sling-shot like boost from Earth’s gravity, it would continue the 2.8 billion kilometer trip (1.7 billion miles) until July 5th, 2016. It’s mission is Jupiter.
Juno will study Jupiter’s gravity and magnetic fields. They are incredibly intense. Jupiter’s magnetic field is something in the neighborhood of 20,000 times that of the Earth’s. HUGE! A magnetic field creates a magnetosphere around the object that forms it. Jupiter’s magnetosphere starts to redirect the solar winds almost 3,000,000 kilometers (1,864,114 miles) before they ever reach (if at all) Jupiter. Juno will also try to discover how Jupiter formed. We hope to find out once and for all if it has a rocky core. Speculation is high on both sides of that argument. We should be able to tell if water is present within the atmosphere, and learn more about its atmospheric winds, some of which can reach speeds of 618 kilometers per hour (384 mph).
The Juno Spacecraft
Juno is an amazing machine. It has a laundry list of technology aboard that will serve a myriad of functions. Its got a microwave radiometer, a magnetometer, a radio and plasma wave sensor, and my personal favorite… a JEDI! YEAH! Now… JEDI is ,of course, an acronym. It stands for Jovian Energetic-particle Detector Instrument. It measures ions and electrons in the magnetosphere. Also on-board is an untraviolet spectrograph, and infrared auroral mapper called JIRAM, and JunoCam! JunoCam is a visible light camera and telelscope. Now… don’t get all excited. It is expected to be on for only around 8 orbits due primarily to Jupiter’s unbelievable radiation and magnetic field. At full expansion it is 66 feet across and 15 feet high. Think of 4 RV’s – three end-to-end that form a “Y” and one more stacked on those at the center. That’s a pretty close approximation. Oddly enough though… the thing only weighs about three and a half pounds!
Juno’s Odd Path of Discovery
The Juno spacecraft cannot just simply enter into an orbit around Jupiter. The planet and its fields would simply destroy the craft before any real data could be acquired. No, Juno is not an orbiter like Cassini. It must get a vast majority of its data collection done on the fly. Scientists and engineers at NASA’s Jet Propulsion Laboratory (JPL) have spent years designing the flight paths that Juno will use. Essentially, Juno will travel about to within about 4,200 km (2,600 miles) of Jupiter then back out, and back in again, over and over in a kind of cork-screw like pattern; each pass covering roughly about 75,600 km (47,000) round trip. Seems a bit odd, until one looks at the magnetosphere I keep bringing up. There are points very close to the planet where Juno can sneak in and then back out again in order to avoid the most dangerous areas. Over the course of some 37 orbits Juno will do just that. 20 months later, over the course of five and half Earth days, Juno will plunge into the Jovian atmosphere. We hope it will still be able to report its findings as it meets its end.
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