2015 was an awesome year for getting to know our nearest celestial neighbours. We flew around a rubber duck-shaped comet, were dazzled by Ceres’ white bits and got to properly meet Pluto for the first time, as New Horizons returned some frankly almost pornographic images of the dwarf planet.
So what do we have to look forward to next year? Stick these in your diary:
March 14: ExoMars launch
The first of ESA’s ExoMars missions sets off this spring, its main objective to figure out how life originated in the solar system, and whether there was, or is, life on Mars. We’re sending two vehicles to Mars – the Trace Gas Orbiter (TGO) will search for trace gases in the Martian atmosphere, including methane, which indicates biological or geological processes, while the Schiaparelli lander will take atmospheric measurements from the surface.
The mission will also test out technologies for ESA’s future excursions to Mars, including ExoMars 2018, which will bring a rover to the red planet.
The fun begins on October 19, when the TGO enters Mars’ orbit, and lander Schiaparelli touches down and gets to work in Meridiani Planum, a plain near the Martian equator.
July 4: Juno’s nearest approach to Jupiter
After a five-year journey, NASA’s Juno will reach our solar system’s largest planet by summertime. Although we’ve flown by Jupiter no fewer than seven times since Pioneer blazed the trail in 1973, we’re still in the dark about how the titan formed: Is it the product of a massive planetary core that captured most of the material left over after the Sun was born, or did it arise from an unstable region within the nebula?
Jupiter’s secrets have been hidden behind a dense veil of swirling gaseous hell:
Juno, named after the Roman god Jupiter’s wife (and sister – those were the days), will peer behind this veil, determining how the interior of Jupiter is composed, mapping the planet’s atmospheric variations and checking out the poles, to see how its magnetic field affects its atmosphere, over the course of 20 months.
Understanding Jupiter’s life story will give us a better idea about how the rest of the solar system formed.
September 3: OSIRIS-REx launch
In September, NASA’s OSIRIS-REx will start its four-year journey to an asteroid called Bennu, a 492m rock in near-Earth orbit that was discovered in 1999. The mission, which completes NASA’s New Frontiers programme (the other two being New Horizons and Juno) will return 60g of asteroid rock back for study – a first for the US.
What’s with the name? Osiris was the ancient Egyptian lord of the underworld, and stands for Origins-Spectral Interpretation-Resource Identification-Security. The ‘REx’ stands for Regolith Extractor. Bennu was named after a bird from the same mythology by a third grader (age 9 to 10) who thought the craft resembled it.
We’re interested in Bennu as it’s made from the ingredients of the early solar system – rock and organic material – components that could help us understand the origin of life and the Earth’s oceans. It also has a slim chance of hitting the Earth 100 or so years from now (hence all the underworld business). Bennu’s orbit isn’t as predictable as we’d like due to the Yarkovsky effect, a phenomenon where after the Sun’s energy cooks one side of a celestial body, subsequent radiation of the heat away from the body “pushes” it into a different orbit.
OSIRIS-REx will give us better understanding of this effect, knowledge we can use if Bennu does start to wander a bit closer to us.
November 29: Cassini begins “Grand Finale”
Cassini has been one of the hardest working spacecrafts in history. As well as sending us back some stunning images of Saturn, the solar system’s resident show off, Cassini brought our attention to the icy geysers of Enceladus, making the moon a serious candidate for discovering life.
Cassini has gone well beyond its original call of duty. It entered Saturn’s orbit in 2004 after a seven-year journey, its primary mission slated at just four years. It’s now been at work for nearly half a Saturnian year now, and as summer the planet’s northern hemisphere we’re starting to see what was in darkness when we arrived.
As we go into 2016, Cassini is warming up for some orbital gymnastics in its grand finale – a set of deep dive orbits that will see it loop around Saturn 22 times, each time passing between the planet and its ring system.
These death-defying dives will help us understand more about the planet’s magnetic field and mass of its rings. Cassini will also map Saturn’s gravitational and magnetic fields on its loop-the-loop, revealing how the planet’s composed on the inside.
In 2017, after 20 years of service, Cassini will be crashed into Saturn to avoid any possible contamination of Enceladus and Titan, “the biologically interesting moons”.