New Horizons explores the outer confines of the solar system

Illustration of NASA’s New Horizons spacecraft encountering Ultima Thule
Credit: Nasa/JHUAPL/SwRI
Illustration of NASA’s New Horizons spacecraft encountering Ultima Thule
New Horizons explores the outer confines of the solar system

On January 1, the New Horizons interplanetary probe will write a new chapter in the history of space exploration by visiting for the first time a Kuiper Belt object.

Launched in January 2006, the probe’s main mission was to explore Pluto, which was still considered a planet at the time of launch. After successfully completing its mission in July 2015, the probe was placed in an orbit enabling it to fly by asteroid 2014 MU69, which was named Ultima Thule by NASA following a public naming contest. The ancient phrase means, roughly, “Beyond the farthest frontiers”.

What is Ultima Thule?

Discovered in 2014 by the Hubble Space Telescope, Ultima Thule is a small rocky object of approximately 25 km in diameter located in the Kuiper Belt, an outer region of the solar system that contains many primitive bodies made of rock. These objects were formed from the dust found in the early days of the solar system, 4.6 billion years ago. Since they have changed very little since their formation, these bodies allow us to study the type of material of which the early solar system was composed and ultimately to understand how planets such as Earth were formed.

Ultima Thule is located 6.6 billion km from us. The amount of light it receives from the Sun is 2,000 times less strong than that received by Earth. Preliminary observations with ground telescopes show an elongated or double body of 25 km in length. Ultima Thule will only be seen by New Horizons in the hours preceding the flyby. We will therefore only discover the secrets of this far-off body much later.

20 months to transmit the data

On January 1, 2019 at 12:30 a.m., New Horizons will fly by Ultima Thule at a distance of 3,500 km. It will sail by the asteroid at a speed of 52,000 km/h and collect 50GB of information in a single day. Since data transmission to Earth can only be done at 1KB/sec., it will take more than 20 months for all the data to make its way to us.

Additionally, because of its remoteness, signals from the New Horizons probe will take up to 6 hours to reach Earth. The first Ultima Thule image should be received in the afternoon of January 1. It will be unveiled to the public on January 2, after having been processed by the mission team.

Astronomers are keen to discover this primitive object orbiting a still unexplored region of the solar system. They have many questions: Is Ultima Thule a unique elongated body or two fragments with a common orbit? Does it have an atmosphere? Are there any moons orbiting around the object or does it have a ring? Etc.

There’s no doubt about it – January 1, 2019 marks an unprecedented exploit that will help us to extend the frontiers of space exploration. An exciting adventure to follow.

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