More flybys, launches, orbital insertions and an unparalleled spell of planetary exploration. This year has ben aptly announced by NASA as the Year of the Solar System (YSS). The year will shed new light on the origin of the solar system, as planetary data and computer models will change our view of how the solar system was formed.

Last year marked many astounding astronomical ventures that paved the path towards exploration of the solar system. The action began in October 2010 with an appearance by Comet Hartley 2. On October 20, Hartley 2 had a close encounter with the earth; it was visible to the naked eye and became a splendid target for backyard telescopes.

Amateur astronomers witnessed the comet as NASA’s Deep Impact/EPOXI spacecraft dived into its vast green atmosphere and plunged towards the icy core. The Deep Impact spacecraft, which studied periodic comet 9P/Tempel 1 in 2005, examined 103P/Hartley 2 in 2010, as part of the EPOXI (Extrasolar Planet Observation and Deep Impact Extended Investigation) mission. The closest approach occurred on November 4, when the minimum distance to the comet was around 620 miles. The spacecraft used two telescopes with digital colour cameras and an infrared spectrometer. The latter determined the chemical composition of outbursts of gas from the comet’s nucleus.

Experiments in astrobiology

In November, NASA launched O/OREOS (Organism/Organic Exposure to Orbital Stresses), a shoebox-sized satellite designed to test the durability of life in space. This exposed a collection of organic molecules and microbes to solar and cosmic radiation. The O/OREOS satellite managed by NASA’s Ames Research Centre was successfully launched on November 19, 2010, from Alaska Aerospace Corporation’s Kodiak Launch Complex on Kodiak Island, Alaska. The satellite rode into orbit aboard a four-stage Air Force Minotaur IV rocket. The mission aimed to conduct low-cost astrobiology experiments on autonomous nanosatellites in space. Scientists applied the knowledge they gained from O/OREOS to plan future experiments to study how exposure to space changes organic molecules and biology.

On December 7, 2010, Japan’s Akatsuki (Venus Climate Orbiter) spacecraft was launched, but failed to enter Venus’ orbit. A second attempt has been planned by Japan’s Aerospace Exploration Agency.

More action this year

The action will continue into this year as NASA spacecraft, Stardust NExT, encounters Comet Tempel 1 on February 14, and MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) enters orbit around Mercury on March 18, and Dawn begins its approach to asteroid Vesta in May.

The launches of Juno spacecraft to Jupiter in August, Gravity Recovery and Interior Laboratory (GRAIL) to map the gravitational field of the moon in September and a rover called Curiosity to Mars in November are other events that this year will see. The spirit of the year will continue into 2012 with the Mars Rover Opportunity running the first-ever Martian marathon. Originally designed to travel no more than 0.6 miles, Opportunity’s rest stop at Endeavour will put it just miles away from finishing an epic run.

Juno is a NASA New Frontiers mission to the planet Jupiter. It was originally proposed at a cost of approximately US$700 million for June 2009 launch. The budgetary restrictions of NASA resulted in Juno being re-scheduled to an August 2011 launch. The spacecraft will be placed in a polar orbit to study the planet’s composition, gravity field, magnetic field, and polar magnetosphere. Juno will also search for clues about how Jupiter formed, including whether the planet has a rocky core, the amount of water present within the deep atmosphere, and how the mass is distributed within the planet.

The GRAIL mission is part of NASA’s Discovery programme. It is scheduled to launch this year. GRAIL will fly twin spacecraft in tandem orbits around the moon for several months to measure its gravity field in unprecedented detail. The mission also will answer longstanding questions about Earth’s moon and provide scientists a better understanding of how Earth and other rocky planets in the solar system formed. Dawn will conduct a detailed study of the structure and composition of two of the first bodies formed in our solar system: the dwarf planet Ceres and the massive asteroid Vesta.

The theme of this memorable event for the year 2011 is ‘Small Bodies, Big Impacts’ and for the year 2012 is ‘Discovering New Worlds.’ The discovery of massive gas giants in sizzling orbits right next to their stars and planets in wildly elliptical orbits have forced us to re-evaluate the evolution of our own solar system.