2015 marks an exciting year for unprecedented space exploration in our solar system. Right this moment, as you are chilling on Earth, over a million kilometers away (three times the distance from the earth to the moon), NASA’s unmanned space probe Dawn is hurtling through the asteroid belt- the region in our inner solar system located between the orbits of Mars and Jupiter. Launched in September 2007, its primary mission was to gather images and data about the protoplanet Vesta and the recently termed dwarf planet Ceres-the two largest objects in the asteroid belt. Ceres being the largest object in the asteroid belt and the only dwarf planet residing in our inner solar system, it is believed to have a rocky core with a 100km thick icy inner mantle. This makes Ceres a potential candidate for harboring life with astronomers estimating that it has more water than earth, a whopping 200 million cubic kilometers of water – almost seven times the volume of the Antarctic ice sheet.
The Dawn spacecraft looks like a typical satellite you would imagine hovering in orbit around Earth – 65 foot (20 metres) wide, composed of two long panels or ‘wings’ joined in the middle by a busy mechanical body with numerous instruments attached, a framing camera which is equipped for navigation and obtaining a global view of Ceres, a visible and infrared mapping spectrometer (VIMS) to take pictures in wavelengths of colour far greater than the human eye can detect (between 300 and 5100 nanometres), and a gamma ray and neutron spectrometer to provide Information about the elemental composition of the planet’s crust, to name a few.
After completing a 14-month survey of Vesta in September 2012 and having collected an astonishing array of high-resolution images, permitting researchers to map its geographical topography and determine information about its atmosphere and gravitational field, the $466 million probe is now en route to Ceres and I quiver in my Doc Marten boots with excitement about the secrets it may reveal. So what’s the story with this 950 km wide sphere of icy rock orbiting our sun? Ceres was the first of its kind to be recognised – a smaller class of planet- like Pluto – and relative to the size of the universe is pretty much located on Earth’s doorstep. Discovered in 1801 by the Italian astronomer Giuseppe Piazzi, he named it Ceres after the Roman Goddess of agriculture and fertility. It is only now over two centuries later that NASA is finally investigating this mysterious entity.
Origin of water
“It’s a big place. It’s a whole alien world,” states Marc Rayman, Dawn’s mission director and chief engineer at NASA’s Jet Propulsion Laboratory, California. Too right, Marc. Not only that but an alien world whose surface composition is a mixture of ice, water and hydrocarbons and emits clouds of water vapour! Bizarrely enough, in January 2014, the European Space Agency (ESA) reported “localized sources of water vapor” being emitted from Ceres. Detected by their infrared Herschel space telescope, researchers speculated that this may be an anomaly caused by heating from the sun causing its ice to be transformed into a water phase, a process called sublimation. Reported in the scientific journal Nature, Dr Michael Kuppers postulates that the water evaporation could be a result of “comet-like sublimation” or due to “cryo-volcanism” whereby volcanoes on Ceres surface erupt water instead of molten rocks. Very cool indeed, as we can take this as hardcore evidence that water exists on this planet. This occurrence may even point to underground bodies of water such as lakes or oceans. Bearing many similarities to Jupiter’s icy moon Europa and Saturn’s geyser-spouting moon Enceladus- Scientists are hopeful Ceres could unlock questions about the origin of water in the cosmos and the evolution of our solar system.
Anticipation is mounting as Dawn is now less than 400,000 miles from enigmatic Ceres with it’s ion propulsion engine thrusting it steadily along at 450mph (725km/h). It works by electrically charging Xenon gas, causing the now charged Xenon particles or ions to be expelled through a metal grid into space at speeds of up to 90,000 miles/hour. In zero-gravity space, the longer the trajectory- or length of time the engine has been thrusting (in Dawn’s case 5 years) – means that the space probe is gradually accelerating with time, accumulating a super high velocity. Scheduled to arrive early in March 2015, it will be permanently stationed in Ceres’ orbit, destined to voyage no further. NASA haven’t released a new photo of Ceres since 2004 and I can’t be the only one curious to see it up close. “Before the Dawn mission, Vesta and Ceres were among the last unexplored worlds in the inner solar system. We are about to unveil a mysterious orb that has beckoned for more than two centuries. It holds secrets from the dawn of the Solar system,” Rayman said.
Another notable NASA missions taking place this year is the launch of a Soil Moisture Active Passive (SMAP) instrument on January 29th, which will measure the quantity of water in the earth’s soil. SMAP is NASA’s response to the threats posed by climate change. By measuring Earth’s vital signs, scientists are optimistic that accurate maps of global soil moisture should help predict weather patterns, floods, drought and landslides and provide a clearer picture of how our planet is changing. NASA’s New Horizons spacecraft has been cruising to Pluto since January 2006 and is destined to arrive in July 2015. Later in 2015, a growth chamber unit will land on the moon with Arabidopsis, basil and turnip seedlings to test the lunar environment for plant germination. This will be the first life science experiment conducted in space and if plant growth prevails over lunar gravity and radiation then this will undoubtedly have far-reaching implications for our future. It’s certainly going to be a profound year for discovery and adventure in our corner of the Milky Way. Hold tight and watch this space!
Illustration: Sarah Larragy