New Horizons: NASA’s New Frontiers Program

The New Frontiers Program aims to carry out targeted planetary science investigations while utilizing effective management techniques. The main goal of the program is to provide unique scientific insights through Solar System exploration. The Planetary Data System (PDS) archive will be expanded to include scientific data, maps, and other products so that all scientists can access them. Additionally, the New Frontiers Program will announce scientific progress and results in peer-reviewed literature, popular media, and materials that can be used to inspire and motivate researchers. By utilizing present participation as Co-Investigators and other team members, as well as the application of technology advancements proved in related initiatives, more highly qualified PIs and project managers will be available to carry out upcoming missions in New Frontiers and other programs. New Horizons, Dragonfly, Juno, and OSIRIS-REx are missions that support this program.

The first mission in NASA’s New Frontiers program, a medium-class, selectively chosen, and principal investigator-led series of missions was called New Horizons.  New Horizons is a NASA mission to explore the dwarf planet Pluto, its moons, and other objects located in the solar system’s Kuiper Belt, which stretches from about 30 AU (orbital distance) near Neptune’s orbit to about 50 AU (orbital distance) from the Sun.

Design and Instruments

NASA and Johns Hopkins University’s Applied Physics Laboratory (APL) collaborated to create and operate the New Horizons spacecraft. After two failed launches due to a power outage and strong winds, New Horizons successfully launched into space on its third attempt. It was launched on 19^th January 2006, at 19:00:00 UT using Atlas V 551 (AV-010) as the launch vehicle from Cape Canaveral, Florida / Launch Complex 41. Scientific tools such as the Ralph Visible and Infrared Imager/Spectrometer, Alice Ultraviolet Imaging Spectrometer, Radio-Science Experiment (REX), Long-Range Reconnaissance Imager (LORRI), Solar Wind and Plasma Spectrometer (SWAP), Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI), and Student Dust Counter were included (SDC) were included here. The spacecraft’s design was based on a genealogy that could be traced back to the CONTOUR, and TIMED spacecraft, which were both created by the Johns Hopkins University Applied Physics Laboratory. A cylindrical radioisotope thermoelectric generator (a spare from the Cassini mission) that produced around 250 W of electricity at launch is also carried by New Horizons in addition to its collection of scientific instruments (decaying to 200 W by the time of the Pluto encounter).

Events and Discoveries

Our understanding of solar system objects that orbit a distance from the sun is constantly being revolutionized by observations from New Horizons. The first spacecraft to investigate Pluto up close was NASA’s New Horizons, which passed by the dwarf planet and its satellites on 14^th July 2015. On 1^st January 2019, New Horizons passed by Arrokoth (2014 MU69), the farthest distant object ever investigated up close and its second major science target.

On 28^th January, 30^th January and 9^th March 2006, controllers conducted course corrections. New Horizons passed the orbit of Mars a month later, on 7^th April 2006. On 13^th June 2006, New Horizons passed by the small asteroid 132524 APL at around 63,300 miles, providing an opportunity to test some of the spacecraft’s equipment, including Ralph (the visual and infrared imager and spectrometer). On 28^th February 2007, the spacecraft made a gravity-assist pass by Jupiter, the largest planet in the solar system, with the closest approach occurring at 05:43:40 UT. The spacecraft’s journey to Pluto was cut by three years thanks to the contact, which raised its velocity by around 9,000 miles per hour.

Early in 2007, New Horizons conducted a thorough series of observations during the flyby over four months. Building on Galileo’s findings, these observations were intended to collect new information about Jupiter’s atmosphere, ring system, and moons, as well as to evaluate New Horizon’s instrumentation. Even while New Horizons observed the moons from a distance considerably greater than Galileo did, it was nevertheless able to send back stunning images of Io, Europa, and Ganymede, including shots of its surface eruptions. On 25^th September 2007, New Horizons made a course correction and accelerated into the Kuiper Belt after its collision with Jupiter. Beginning on 28^th June 2007, the spacecraft entered hibernation mode. During this time, the onboard computer monitored mission systems and transmitted special codes indicating whether activities were normal or abnormal. Most of New Horizons’ primary systems were turned down during hibernation and only partially turned back on annually, for around two months. 16^th December 2008, 27^th August 2009, and 29^th August 2014, respectively, were the second, third, and fourth hibernation cycles.

On 25^th February 2010, New Horizons reached Pluto from halfway around. Concerns that there might be dust or debris in Pluto increased with the finding of the new Pluto moons Kerberos and Styx during the expedition. In case the number of debris grew as the spacecraft got closer to Pluto, mission planners came up with two potential backup plans: either employing the antenna facing the oncoming particles as a shield or flying closer to Pluto where there might be less debris. For the last time, on 6^th December 2014, ground controllers brought New Horizons out of hibernation to begin its actual approach with Pluto. A signal from the spacecraft took four hours and twenty-five minutes to arrive on Earth at that time. On 15^th January 2015, the spacecraft started its approach phase toward Pluto. A 93-second thruster burn was used on 10^th March 2015, to adjust the spacecraft’s trajectory. Two days later, with just over four months left before its near approach, New Horizons finally surpassed Earth’s distance from the Sun. By 29^th April 2015, images of Pluto started to show distinct features, with the level of detail growing week by week as the approach continued.

On 29^th June 2015, a final 23-second engine fire advanced New Horizons by around 11 inches per second toward its objective and adjusted its trajectory. As intended, New Horizons did not communicate with Earth during its closest approach to Pluto and its largest moon, Charon, in July 2015 because it was too busy collecting data. The full dataset gathered during Horizons’ encounter with Pluto and Charon reportedly took 15 months to download, according to NASA. This was because New Horizons’ data transmission rate was barely 1-2 kilobits per second and its overall data size was 6.25 gigabytes. On 4^th July 2015, when New Horizons entered safe mode because of a timing error in the spacecraft command sequence, there was cause for alarm.

The second-most important research target for New Horizons, the Kuiper belt object 2014 MU69, the most distant object ever studied up close, was passed by on January 1, 2019. It has been given the official name Arrokoth, a Native American term that means ‘sky’ in the Powhatan/Algonquian language. This is an appropriate homage to the farthest flyby ever made by a spacecraft.

Dr. Stern reports that the New Horizons spacecraft is still functioning well in the Kuiper belt in 2022. It is currently traveling away from the Earth and Sun at a rate of around 300 million miles per year.

References:

1. NASA. (n.d.). New Frontiers Program. https://www.nasa.gov/planetarymissions/newfrontiers.html
2. Howell, E. (2021, October 20). New Horizons: Exploring Pluto and Beyond. Space.com. https://www.space.com/18377-new-horizons.html

Image Courtesies:

1. Featured image: https://go.nasa.gov/3GfDu1x
2. Image 1: https://bit.ly/3Z01EEG
3. Image 2: https://bit.ly/3vlUqwQ
4. Image 3: https://bit.ly/3FSk29O