NASA’s New Horizons spacecraft wakes after 321-day hibernation

New Horizons Wakes Up After 321 Days of Hibernation

Following its longest hibernation period ever, the New Horizons spacecraft is now transitioning from its resource-saving state back into active research. The probe, which has been traveling through the cold, dark fringes of the solar system, was placed into hibernation on August 7 of last year to conserve power during its cruise through the Kuiper Belt.

The successful wakeup was confirmed by flight controllers at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland. The spacecraft acted on stored commands that had been uplinked to its main computer last July. Because the spacecraft is approximately 5.9 billion miles from Earth, the radio signals carrying that confirmation took about 8 hours and 52 minutes to reach the APL Mission Operations Center via NASA’s Deep Space Network station near Madrid, Spain.

Alice Bowman Confirms Green Status for New Horizons

Alice Bowman, the New Horizons mission operations manager at APL, noted that the probe maintained a consistent green status throughout the nearly year-long hibernation. “Every status report through this hibernation period was ‘green,’ meaning all was well aboard New Horizons each and every week,” said Bowman in a NASA statement. With the craft now awake, the ground team is preparing to downlink stored health and safety data, followed by the scientific observations collected by its onboard instruments while the probe was in its low-power mode.

Southwest Research Institute Analyzes Solar Wind Speed

New Horizons is currently positioned to conduct unique measurements of the solar wind, the stream of charged particles emanating from the sun. Researchers are particularly interested in the termination shock, a boundary where solar wind particles lose significant speed. New measurements indicate the solar wind is 13 to 15 percent slower in these outer reaches than it is near Earth. Scientists predict the solar wind will slow much more dramatically when New Horizons reaches the termination shock, where particles suddenly lose speed. Voyager 2, currently 13.3 billion miles away, previously measured a 46-percent drop in solar wind speed when it reached that point.

While the Voyager probes previously crossed this boundary, New Horizons is equipped with more sensitive instrumentation. According to researchers at the Texas-based Southwest Research Institute, the spacecraft’s data will help map the edge of the sun’s influence and provide insights into the boundary between our solar system and interstellar space. Not only do we learn more about how the sun’s influence ends, said Heather Elliott, a researcher at the Southwest Research Institute and first author of the paper published in The Astrophysical Journal, “but we also gain a deeper understanding of the boundary between our solar system and interstellar space — a critical step toward planning future interstellar travel.”

In approximately three weeks, the spacecraft will begin conducting a study of hydrogen in the outer heliosphere. Simultaneously, other instruments—including the Venetia Burney Student Dust Counter, the Solar Wind at Pluto, and the Pluto Energetic Particle Spectrometer Science Investigation—will continue their ongoing measurements of the deep-space environment. As noted by Pontus Brandt, New Horizons project scientist at APL, “The data from the termination shock encounter will be a treasure trove for space physicists worldwide who are eager to understand how this vast boundary works.”

Alan Stern Uses the Vera C. Rubin Observatory to Find New Targets

New Horizons launched 20 years ago, flying past Jupiter in 2007 for a gravity boost. It became the first spacecraft to explore the Pluto system in 2015. Four years later, it studied the snowman-shaped planetesimal Arrokoth, one billion miles (1.6 billion kilometers) past Pluto. The mission is expected to continue operations into the 2050s, potentially reaching a distance 100 times farther from the sun than Earth. As the spacecraft continues its journey away from Earth at a rate of 300 million miles (483 million km) per year, the team is currently utilizing the Vera C. Rubin Observatory to identify potential future targets. As noted by Alan Stern, the mission’s principal investigator, the discovery of a previously unknown population of distant objects beyond the known Kuiper Belt with the craft’s long-range camera could mean the belt extends much farther than expected or that a second, more-distant belt of icy bodies exists beyond it.

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