Having flown by Pluto in 2015,NASA'S New Horizons spacecraft is now well beyond the dwarf planet on its journey to another Kuiper Belt Object (KBO),a small body of an unknown nature called KBO MU69.NH is planned to execute a flyby of it on 1 January 2019,setting a record for the most distant celestial object ever explored in a flyby.
The Kuiper Belt is a region of the solar system rich in celestial objects believed to be from the early days of our system's formation,such as dwarf planets;thousands of icy bodies more than 62 miles/100 km across;and an estimated at least one trillion comets.*
NASA is striving to learn all it can about MU69 before NH reaches it,in order ensure it will not collide with any debris or ring systems which may be in this unexplored region.Data from the Hubble Space Telescope and ESA Gaia satellite are being used to calculate where MU69 will cast its faint shadow on the Earth's surface as it passes in front of a star (an occultation event).So far,there have been three such events monitored by NASA and collaborating observers and technicians to prepare for the New Horizons flyby.
One of the events was on 3 June 2017,when more than 50 mission team members and collaborators set up mobile telescopes in South Africa and Argentina in an effort to capture images of MU69's shadow speeding over the Earth for two seconds.Other observations were made by HST and the Gaia space observatory.In the event,the telescopes took more than 100,000 photos of the occultation that can help ascertain the nature of MU69's environment.Indeed,valuable and surprising insights were obtained,mission team members said.
New Horizons science team leader Mark Buie of the Southwest Research Institute in Boulder,Colorado noted that:
These data show that MU69 might not be as dark or as large as some expected.
Principle investigator at the SWRI Alan Stern added:
The fact that we accomplished the occult observations from every planned observing site,but didn't detect the object itself,likely means that either MU69 is highly reflective and smaller than some expected,or it may be a binary,or even a swarm of smaller bodies left over from the time when planets in our solar system formed.*
Occultation observations of MU 69 have also been made on 10 July 2017 by the NASA/German Aerospace Centre SOFIA flying infrared observatory,a converted Boeing 747 with a 2.5 meter telescope that allows for IR study above 99% of the atmosphere's water vapour.That data is currently being analysed.A second mobile telescope round was carried out on 17 July 2017 in Southern Argentina,with the HST also participating.