Tag: flyby

Jovian Joviality: Juno is a Healthy Spaceship, On-Track for 2016 Jupiter Rendezvous

Artist's impression of the Juno flyby (NASA)
Artist’s impression of the Juno flyby (NASA)

Last week’s Juno flyby of Earth was an exciting event. NASA’s Jupiter-bound mission buzzed our planet on Wednesday (Oct. 9) only 350 miles from the surface, providing amateur astronomers with an opportunity to snapshot Juno as she flew past, stealing a little momentum from Earth and sling-shotting toward the largest planet in the Solar System. Alas, the flyby event wasn’t without incident.

The spacecraft dropped into “safe mode” shortly after its terrestrial encounter. Safe mode is a fail safe on spacecraft that protects onboard instruments from an unexpected condition. This can come in the form of a power spike or some other instrumental error. It is not known at this time what triggered this particular event, but the upshot is that Juno is back in its nominal state.

From a Southwest Research Institute news release:

“Onboard Juno, the safe mode turned off instruments and a few non-critical spacecraft components, and pointed the spacecraft toward the Sun to ensure the solar arrays received power. The spacecraft acted as expected during the transition into and while in safe mode.”

Juno’s planned trajectory was not impacted during the flyby and it is expected to make orbital insertion around Jupiter in July 2016.

The mission was launched from Cape Canaveral, Fla., in 2011 and, through a wonderful bit of orbital mechanics, was commanded to do one 2-year orbit around the Sun. Then, last week, it ended up where it started to use our planet as a speed booster, flinging it further out into the Solar System toward Jupiter’s orbit. This acceleration “freebie” was needed as the launch vehicle, an Atlas V rocket, didn’t have the oomph to propel the spacecraft deeper into space.

Once Juno arrives at Jupiter, it will give the gas giant a thorough full-body examination, investigating what lies beneath its clouds, how it generates its powerful magnetic field and how it evolved. The repercussions of Juno’s one-year primary mission will hopefully expose not only how Jupiter is formed, but how Earth evolved into its current state.

As Juno sped past on Wednesday, I allowed myself an early celebration of some fine flying by NASA scientists with a Gin & Tonic (or a Juno & Tonic) in my special JPL-bought Juno glasses.

Good luck Juno, will look forward to seeing you at Jupiter in a little under three years time!

MORE: Read my Discovery News post about the possibility of Juno exhibiting the mysterious “flyby anomaly.”

Cassini Detects Salt: Enceladus Probably Has a Liquid Ocean

The small icy Saturn moon might have liquid sub-surface oceans after all (NASA)

In October 2008, Cassini flew very close to the surface of Saturn’s icy moon Enceladus. From a distance of only 50 km from the moon, the spacecraft was able to collect samples of a plume of ice. In an earlier “skeet shot”, Cassini captured detailed images of the cracked surface, revealing the source of geysers blasting the water into space. At the time, scientist were able to detect that it was in fact water ice, but little else would be known until the molecular weight of chemicals in the plume could be measured and analysed.

At the European Geophysical Union meeting in Vienna this week, new results from the October Enceladus flyby were presented. Frank Postberg and colleagues from the Max Planck Institute for Nuclear Physics have discovered traces of sodium salts and sodium bicarbonate in the plume for the first time.

It would appear that these chemicals originated in the rocky core of the moon and were leached from the core via liquid water. The water was then transported to the surface where it was ejected, under pressure, into space. Although scientists are aware that the chemical composition in the plume may have originated from an ancient, now frozen, sub-surface ocean, the freezing process would have isolated the salt far from the surface, preventing it from being released.

“It is easier to imagine that the salts are present in a liquid ocean below the surface,” said Julie Castillo of NASA’s Jet Propulsion Laboratory in Pasadena, California. “That’s why this detection, if confirmed, is very important.”

This is the best evidence yet that Enceladus does have a liquid ocean, bound to cause a stir amongst planetary scientists and re-ignite excitement for the search for life living in a salty sub-surface ocean.

Source: New Scientist