At a Glance
- The New Horizons spacecraft, located over 5.5 billion miles from Earth, has successfully demonstrated a new method for deep-space navigation using nearby stars as reference points.
- Researchers imaged Proxima Centauri and Wolf 359 simultaneously from Earth and the spacecraft to measure their apparent positional shift, an effect known as stellar parallax.
- This parallax measurement allowed the team to calculate the spacecraft’s three-dimensional location relative to the stars with an accuracy of about 4.1 million miles, a groundbreaking proof-of-concept.
- The experiment is the first time optical astrometry has been used to determine a spacecraft’s position on an interstellar trajectory, with results published in The Astronomical Journal.
- A key conclusion is that using a few of the closest stars for navigation is more effective for interstellar probes than using a large sample of more distant stars.
As NASA’s New Horizons spacecraft hurtles toward the edge of our solar system, it has served as a remote celestial observatory for an unprecedented experiment in deep space navigation. An international team of astronomers used the distant probe to triangulate its position by measuring the apparent shift of two nearby stars, a groundbreaking demonstration with profound implications for future interstellar missions. The research, led by Tod Lauer of the National Science Foundation‘s NOIRLab, was accepted for publication in The Astronomical Journal.
The technique relies on a simple visual effect known as stellar parallax. Just as holding a thumb at arm’s length and closing one eye at a time makes it appear to jump against the background, stars that are relatively close to us seem to shift their position when viewed from two widely separated locations. On April 23, 2020, researchers imaged the stars Proxima Centauri and Wolf 359 from both Earth and New Horizons, which was over 5.5 billion miles away, creating the largest distance between two observation points ever used for a parallax measurement.
By comparing the images and referencing a precise three-dimensional map of our stellar neighborhood, the team successfully calculated the spacecraft’s location in space relative to the stars. They pinpointed its position with an accuracy of about 4.1 million miles. While this initial test was intended as an educational proof-of-concept rather than a high-precision measurement, it marks the first time any method of interstellar navigation has been successfully demonstrated for a spacecraft on a trajectory to leave our solar system.
This achievement not only offers a visually compelling example of parallax but also establishes a new strategy for guiding future probes on their journeys to the stars. The study concluded that for interstellar navigation, using a single pair of the closest stars is more effective than relying on an extensive catalog of more distant ones. As New Horizons continues its voyage beyond Pluto and through the Kuiper Belt, it has paved the way for the next generation of explorers to chart their course through the vast emptiness between stars confidently.
References
- Blue, C. & Phys.org. (2025, July 4). New Horizons conducts first-ever successful deep space stellar navigation test. Phys.Org; Phys.org. https://phys.org/news/2025-07-horizons-successful-deep-space-stellar.html
- Lauer, T. R., Munro, D. H., Spencer, J. R., Buie, M. W., Gomez, E. L., Hennessy, G. S., Henry, T. J., Kaplan, G. H., Kielkopf, J. F., May, B. H., Parker, J. W., Porter, S. B., Vrijmoet, E. H., Weaver, H. A., Brandt, P., Singer, K. N., Stern, S. A., Verbiscer, Anne. J., Acosta, P., … Zambelis, D. (2025). A demonstration of interstellar navigation using new horizons. The Astronomical Journal, 170(1), 22. https://doi.org/10.3847/1538-3881/addabe
