Concerns about the health of the Juno spacecraft’s main engine have compelled NASA managers to keep the research probe in its current arcing, high-altitude orbit around Jupiter, a decision that will delay the full science return from the $1.1 billion mission but should still allow it to meet all predetermined objectives.
NASA’s Juno spacecraft made a high-speed pass less than 3,000 miles over Jupiter’s turbulent clouds Thursday, taking dozens of pictures, measuring radiation and plasma waves, and peering deep inside the planet’s atmosphere, but officials still have not cleared the orbiter’s main engine for a planned maneuver to position the probe for improved science observations.
Scientists planning the the next phase of NASA’s New Horizons mission, a robotic craft that completed the first exploration of Pluto in 2015, are going into the flyby of a frozen, faraway city-sized clump of rock on New Year’s Day 2019 armed with little knowledge of the target lurking around 4 billion miles from Earth.
A team of scientists has documented atmospheric changes on Io, Jupiter’s volcanically active satellite, as the giant planet casts its shadow over the moon during daily eclipses. Io’s thin atmosphere collapses as the sulfur dioxide gas emitted from volcanoes freezes when shaded by Jupiter. The atmosphere reforms when Io moves out of eclipse and the ice sublimates.
Ceres is covered in countless small, young craters, but none are larger than 175 miles (280 kilometres) in diameter. To scientists, this is a huge mystery, given that the dwarf planet must have been hit by numerous large asteroids during its 4.5 billion-year lifetime. Where did all the large craters go?