New Horizons

New Horizons is an interplanetary space probe designed to explore the outer reaches of our Solar System.

It is part of NASA's New Frontiers program. This program funds missions that are larger than Discovery missions but smaller than Flagship missions. The primary goal of New Horizons is to study the formation of the Pluto system and the Kuiper belt. By examining these distant objects, scientists hope to understand how the early Solar System transformed over time.

The spacecraft follows a complex path to reach its distant targets. It launched on January 19, 2006, from Cape Canaveral Space Force Station. An Atlas V rocket carried it into an Earth-and-solar escape trajectory. At launch, it was the fastest human-made object ever sent from Earth.

On February 28, 2007, the probe made its closest approach to Jupiter. This flyby provided a gravity assist, which means the planet's gravity helped increase the probe's speed. During this encounter, the spacecraft also tested its scientific instruments by collecting data on Jupiter's atmosphere, moons, and magnetosphere.

The mission has several distinct phases of operation. After the Jupiter flyby, New Horizons entered a long period of hibernation. This mode was used to preserve the onboard systems during the long journey. The spacecraft only woke up for brief annual checkouts. On December 6, 2014, the team brought it back online to prepare for the Pluto encounter. On January 15, 2015, the spacecraft began its formal approach phase.

History shows that the idea for this mission began decades ago. In August 1992, scientist Robert Staehle contacted Clyde Tombaugh, the man who discovered Pluto. Tombaugh welcomed the idea of a visit, though he noted it would be a long and cold trip. In December 2000, Stamatios "Tom" Krimigis and Alan Stern formed the New Horizons team. Stern served as the project's principal investigator. The team competed against other proposals, such as the POSSE mission from the University of Colorado Boulder.

Funding for the mission was a major part of its history. Although selected in 2001, the mission faced cancellation when the NASA Administrator did not include it in the 2003 budget. To save the mission, Alan Stern lobbied for its inclusion in the Planetary Science Decadal Survey. This survey is a prioritized "wish list" created by the National Research Council. Because the scientific community ranked New Horizons as a top priority, funding was eventually secured. The total mission cost approximately $700 million over 15 years.

New Horizons has achieved many scientific milestones. On July 14, 2015, it became the first spacecraft to fly above the surface of Pluto. It provided the first high-resolution photographs of the dwarf planet.

The probe also studied the Kuiper belt object 486958 Arrokoth. It flew past Arrokoth on January 1, 2019, when the object was 44 AU from the Sun.

Additionally, the Alice instrument helped confirm the existence of a "hydrogen wall" at the edge of the Solar System. This wall was first detected by the Voyager spacecraft in 1992.

The spacecraft itself is a highly specialized machine. It is roughly the size of a grand piano. The main structure is a 7075 aluminum alloy tube. This tube holds a titanium fuel tank. The probe uses a radioisotope thermoelectric generator, or RTG, for power.

It also carries nine cultural artifacts. These include a compact disc with 434,738 names and the ashes of Clyde Tombaugh. The mission is expected to continue until the probe exits the Kuiper belt, which should happen in 2028 or 2029.