All set for epic Pluto encounter in Jan

New Horizon Mission was commissioned in 2006 to study the objects of Kuiper belt region beyond the Neptune and Pluto-Charon, binary planet. Solar system has three classes of planets – the inner rocky or terrestrial planets (Earth, Mars, Mercury and Venus), the gas giants (Jupiter, Saturn, Uranus and Neptune) with by thick molecular hydrogen atmospheres, and the ice dwarfs of the Kuiper belt that has solid surfaces with significant icy material (frozen water, nitrogen, carbon dioxide, methane or carbon monoxide).

There are larger numbers of ice dwarfs than the rocky and gas giants put together, but no spacecraft has been sent to them. New Horizon Mission is set to fill that gap. The ice dwarfs are small planets whose growth stopped when they attained sizes of 200-2,000 km diameter. These are ancient relics from which giant planets have formed four billion years ago. Hence, they have great deal to teach about planet formation. With this mission, the US has made history of sending space probes to all the planets of the solar system. Galvanised by success of Orion spacecraft, NASA is very keen on working on this New Horizon Mission.

Launched from the Cape Canaveral, on January 19, 2006, by Atlas V 551 rocket, the 8-year interplanetary cruise included a flyby of Jupiter in 2007. It crossed the orbits of Saturn in 2008, Uranus in 2011 and Neptune in August 2014. Following its encounter with Neptune, it entered into a slumber to be woken up after a 99 day break on December 6 3 am EST to gear up for a six-month Pluto encounter. It has cruised 3 billion miles (4.8 billion kilometres) and spent two-thirds of its journey in hibernation over the course of 18 separate hibernation periods ranging from 36 to 202 days in duration.

The probe has been pushed into hibernation often to reduce wear and tear and operation costs. Every few months, the probe was awakened for a check-up, whereby it would send weekly blips to the mission known as ‘green beacons’ to say that it’s not dead.

Pluto’s encounter would start technically from January 15, 2015, during which it will probe Pluto and its five moons (Charon, Nix, Hydra, Kerberos and Styx) for the next six months. After Pluto, the mission plans to send the probe past two icy objects in the Kuiper belt, the ring of cosmic belt which lies beyond Neptune by 2018 or 2019, provided funds are sanctioned to the mission.

The $728 million mission has seven objects on board to study geology and topography of Pluto and its largest moon Charon to map the surface compositions and temperatures and study Pluto’s atmosphere and any undiscovered moons and rings in the dwarf planetary system. Pluto and Charon are together referred to as binary planets. The term is used to refer to any pair of worlds that are similar in mass.

Pluto discovered in 1930 is classified by International Astronomical Union as a dwarf planet.

New Horizons mission is highly sophisticated and the smallest space probe ever sent into the solar system. The instruments on board include Alice, an Ultraviolet Spectrometer; LORRI, a camera; Ralph, a multi-spectral imager with five channels; LEISA, an infrared spectrometer; REX, an instrument which sends radio signals to Earth; Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI) to monitor the ions escaping atmosphere of Pluto etc.

By July 14, New Horizons will be nearest to Pluto’s surface, 6,200 miles away. Message from the Earth takes four hours to reach the Pluto, despite travelling at light speed. Since the mission is operating at four billion kilometres distance from Earth in deep space communication mode, transfer of data might be very slow. Sometimes, communication may be impossible when it is focusing on certain points. Scientists expect silence for two weeks when it is too close to Pluto.

Following the wakeup of New Horizons Mission from slumber there is palpable excitement among scientists as this ambitious mission is going to unravel unprecedented information and images about Pluto.

By: Ramaharitha Pusarla