Dawn
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NASA has approved a second extension of the Dawn mission at Ceres, the largest object in the asteroid belt between Mars and Jupiter. The spacecraft will now go on to take a closer look at the space object, informed the space agency.

During this extension, the spacecraft will delve into even lower altitudes than before at the dwarf planet Ceres, which Dawn has been orbiting since March 2015, states a report by Business Standard.

Previously, Dawn's lowest altitude was 385 kilometers, and now the Dawn flight team is developing and studying different ways in order to move the spacecraft into a new elliptical orbit, which may take it to less than 200 kilometres from the surface of Ceres.

Recently, on September 27, Dawn completed its 10 years of spaceflight and now the spacecraft will continue to perform the rest of its science investigation at Ceres, following which it is to remain in a stable orbit indefinitely, as its fuel runs out.

The purpose of extending Dawn's Ceres mission is to collect more data with the spacecraft's gamma ray and neutron spectrometer, which measures the number and energy of gamma rays and neutrons. This information is vital for the scientists to understand the composition of Ceres' uppermost layer and to comprehend how much ice the dwarf planet contains.

As per the report, it will also take visible-light images of Ceres' surface geology with its camera, and the measurements of Ceres' mineralogy with its visible and infrared mapping spectrometer.

Moreover, this extended mission at Ceres will allow Dawn to be present in orbit of the dwarf planet when it goes through perihelion, its closest approach to the Sun, which is scheduled to happen in April 2018. This event is critical because closer proximity to the Sun may turn more ice on Ceres' surface into water vapour, which may, in turn, contribute to the weak transient atmosphere that was detected by the European Space Agency's Herschel Space Observatory before Dawn reached Ceres.

Based on the findings of Dawn so far, researchers have hypothesised that interaction between the energy particles from Sun with the ice on Ceres' shallow surface may produce the water vapour, points out the report.

Scientists will calculate and study all the data gathered from the ground-based observatories and Dawn's observations to further comprehend these phenomena as Ceres approaches perihelion.

For now, the spacecraft is supposed to accomplish as much science data as it can in its final planned orbit, where it will stay even after its communications with Earth are disconnected.

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As per the estimates by the mission planners at NASA, the spacecraft can continue operating until the second half of 2018.

Till date, Dawn is the only mission ever to orbit two extraterrestrial targets. While it had orbited giant asteroid Vesta for 14 months from 2011 to 2012, it now continues its quests on Ceres, where it has been in orbit since March 2015.