First data sent by NASA's latest New Horizons spacecraft provides information that shows the surface of one of Pluto's moons, Hydra, has pristine water ice on a much larger proportion than the earlier cited ice toppings of Charon, the largest of the five known moons of the dwarf planet.
The first compositional data about the four satellites of Pluto, sent by the New Horizons spacecraft, provides more information about the four moons of the planet Pluto.
The new data, gathered by the Ralph / Linear Etalon Imaging Spectral Array (LEISA) instrument, show that Hydra's surface is covered by nearly pristine frozen water.
According to Space Coast Daily, the new compositional data received recently on Earth were taken from a distance of 150,000 miles (240,000 km), on 14 July 2015.
It was earlier found that Pluto's largest moon, Charon, also has crystalline water ice, similar to that of the Hydra spectrum. However, the water ice absorption bands of Hydra are far deeper than that of Charon's.
The ice grains on Hydra's surface reflect more light at certain angles than the grains on Charon, showing these are deeper.
Hydra is the Pluto's outermost small moon and it is thought to have formed in an icy debris disk some four billion years ago. NASA scientists are investigating why Hydra's ice seems to be cleaner than Charon's.
The NASA's New Horizons team expects to obtain similar data on Pluto's other small moons, which will help in comparing Hydra with Charon.
''Perhaps micrometeorite impacts continually refresh the surface of Hydra by blasting off contaminants,'' said Simon Porter, New Horizons science team member from Southwest Research Institute in Boulder, Colorado.
''This process would have been ineffective on the much larger Charon, whose much stronger gravity retains any debris created by these impacts,'' he added in a NASA statement.