Voyager 2’s cameras captured images and sensors gathered data as it passed over Neptune’s cold blue clouds tonight as part of its final journey across our Solar System.
Neptune boasts 14 moons, such as Triton. Geysers of nitrogen erupt from its surface indicating that Triton may have originated as a free-roaming dwarf planet.
Voyager 2
Voyager 2 crew gathered around their monitors as Neptune evolved from a fuzzy blue dot on their screen to an image with greater detail and clarity, gradually showing its Great Dark Spot, swirling clouds, two new small moons, atmosphere, magnetic field and rings. Voyager’s instrument suite examined these aspects as well.
Flight controllers devised the best strategy for Voyager 2’s navigation using computerized test simulations of Neptune system’s geometry, utilizing gravity assists that accelerated and bent its trajectory. Voyager 2 was directed into an approach from behind Triton using gravity assist.
The high-heritage visible/near-infrared imaging system on board provided composite color images of Neptune and its satellites from human eye perspective, supplemented by an education, public outreach (EPO) camera for contextual views and “you are there” perspectives. Instruments’ visible and infrared spectrometers constructed spectra as functions of wavelength for composition measurements as well as auroral observations while other instruments examined solar wind, radiation belts, and magnetosphere observations.
Voyager 3
Voyager 2 and its twin probes – now well beyond the outer edges of our solar system) launched in 1977 – have provided incredible images from Jupiter, Saturn, Uranus, and Neptune as they orbited away from Earth. Their cameras and magnetometers revealed amazing new details about these giant ice worlds with their rings and moons.
Neptune’s intricate ring system was meticulously charted for the first time ever, including its braids and kinks, with three previously unknown moons, an active magnetic field, and stunning aurora displays all discovered as discoveries.
Both Voyagers carry a 12-inch (30 cm), gold-plated phonograph record with symbolic instructions on its cover for playing it as an interstellar message to any civilization, human or alien, that might discover one of these spacecraft. Scientists also used these Voyagers to test whether solar winds might bring particles from distant galaxies into our inner Solar System to form some kind of cosmic web.
Neptune would help scientists better comprehend how our Solar System was formed and reveal clues regarding exoplanet formation.
Voyager 4
Voyager 2 arrived at Neptune on August 25, 1989 after successfully surviving both mechanical and electronic challenges. By that point, it had captured images of Jupiter, Saturn’s rings, pale Uranus moons, volcanic activity on Io’s surface of Jupiter as well as discovering Neptune’s Great Dark Spot storm system-a third the size of Earth.
At that time, Neptune was experiencing an exceptionally hot and long summer season; temperatures had skyrocketed to record levels. Scientists expected extreme temperature shifts over its seasons but none quite as dramatic.
Voyager 2 passed through the heliosheath phase by crossing the boundary between our solar system and interstellar space — known as the heliopause — at about 120 astronomical units from the Sun. Now traveling south under Neptune’s ecliptic, Voyager continues its observations of magnetic fields, charged particles and other cosmic phenomena at this cosmic frontier. Neptune’s gravity will eventually pull Voyager into this region populated with debris such as that which forms two of Triton’s rings — eventually leading it into slow motion collision within 40 years with Neptune’s gravity.
Odyssey
Neptune and Triton hold great fascination for both planetary scientists and exoplanet hunters despite being giant ice planets. Their orbits allow researchers to detect atmospheric gases that reveal information about the chemical makeup of each planet while their gravitational pull helps create rings around each one.
Triton stands out as one of the few planets with a tide-locked moon, offering new opportunities for exploration. A Neptune Odyssey spacecraft could study Neptune’s rings, aurorae, small moons and space environment before passing by Triton multiple times and collecting samples from it.
This mission, proposed as a Flagship-class probe launched from either NASA’s Space Launch System or SpaceX’s Falcon Heavy in 2031 with gravity assist from Jupiter, would reach Neptune 12 years later in 2043 and feature an atmospheric entry probe capable of penetrating through Neptune’s atmosphere to reach its surface, taking 37 minutes before beaming back images back home en route to JPL and beyond. Many at JPL still wish it could happen!