From the February 2007 issue

New Horizons at Jupiter

Follow NASA's New Horizons mission as it whisks past Jupiter.
By | Published: February 19, 2007 | Last updated on May 18, 2023

NASA’s New Horizons spacecraft roared off the launch pad at 2 p.m. EST January 19, 2006, from Complex 41 at Cape Canaveral Air Force Station in Florida. The compact, 1,050-pound (426 kilogram), piano-sized probe got an additional boost from a solid-propellant kick motor for its journey to Pluto.

Thanks to its Atlas V rocket, New Horizons is the fastest spacecraft ever launched. Just 9 hours after blasting off, it surpassed the Moon’s distance, and it reached Jupiter in a record 13 months. The Jupiter flyby’s gravitational assist trims the trip to Pluto by as many as 5 years.

NASA/KIM SHIFLETT New Horizons’ LORRI instrument took this dramatic image of Jupiter’s volcanic moon Io just about 5 hours after the spacecraft’s closest approach to the planet February 28. Io was 1.5 million miles (2.5 million km) away.

Details as small as 7.4 miles (12 km) can be seen on Io. Prominent in the image is the enormous 180-mile-high (290 km) plume from the volcano Tvashtar, at 11 o’clock near Io’s north pole. The Hubble Space Telescope first detected the plume 2 weeks ago; New Horizons caught a glimpse of it February 26.

Io’s dayside was deliberately overexposed in this picture to image the faint plumes, and the long exposure also provided an excellent view of Io’s night side, illuminated by Jupiter. No previous image by any spacecraft has shown these mysterious structures so clearly.

The image also shows the much smaller symmetrical fountain of the plume, about 40 miles (60 km) high, from the Prometheus volcano at 9 o’clock. The top of a third volcanic plume, from the volcano Masubi, erupts high enough to catch the setting Sun on the night side near the bottom of the image, appearing as an irregular bright patch against Io’s Jupiter-lit surface. Several Everest-sized mountains are highlighted by the setting Sun along the terminator, the line between day and night.

This is the last of a handful of LORRI images that New Horizons is sending “home” during its busy encounter. Hundreds more, plus other data, are stored onboard. The rest of the images will be returned to Earth over the coming weeks as the spacecraft speeds along to Pluto.

NASA/JHUAPL/SWRI Ganymede, the solar system’s largest moon, stands out in this February 27 image from the New Horizons spacecraft. The mmon’s icy surface displays a mix of dark, ancient terrain and brighter, younger material. New Horizons was 2.2 million miles (3.5 million km) away when it took this image.

NASA/JHUAPL/SWRI This movie of Jupiter’s atmosphere combines six global maps taken by New Horizons’ LORRI instrument between January 8 and 22, 2007. The high-resolution camera acquired each of six observation “sets” as a series of individual pictures taken one hour apart to cover a full 10-hour rotation of Jupiter.

The Great Red Spot is the prominent gray oval at lower right in this portion of the global animation.

Many features seen in Jupiter’s atmosphere are giant storm clouds. The sequence captures the counterclockwise rotation of clouds within the spot and its westward drift. Note the dramatic changes in the series of large, comma-shaped clouds encircling the planet’s equatorial region. Scientists believe rising, ammonia-rich air condenses to form the plume tails.

The shadow of Jupiter’s moon Ganymede appears in one image as a circular black dot at top left.

NASA/JHUAPL/SWRI Jupiter’s Little Red Spot stands front and center in this three-image mosaic taken by New Horizons February 26. The he spacecraft was 2.1 million miles (3.5 million km) from Jupiter. The Little Red Spot formed from three white ovals that merged during the past decade. In 2006, the storm apparently intensified, and its cloud tops turned red. Observations from the flyby will help scientists understand the storm’s changes.

NASA/JHUAPL/SWRI When New Horizons reaches Pluto in mid-2015, the dwarf planet still won’t have made it halfway around the Sun since its 1930 discovery.

Since the 1980s, Pluto has angled more of its southern hemisphere toward Earth. Earth’s orbit is the smallest circle at center, while the larger ellipses represent the paths of Jupiter, Saturn, Uranus, and Neptune.

This diagram shows the locations and orientations for Pluto at its discovery; the discovery of its moon Charon (1978); its closest point to the Sun and equinox (late 1980s); and the New Horizons flyby (2015).

Will Grundy, Lowell Observatory Although exploring Pluto and the Kuiper Belt is the main mission of NASA’s New Horizons, this month the spacecraft speeds past a bonus target: Jupiter.

Here you’ll find the mission’s latest Jupiter images, as well as others recounting New Horizons’ history and outlining its future. Be sure to check our exclusive New Horizons Updates from the mission’s lead researcher, too.

As part of the encounter, New Horizons will steal a tiny amount of Jupiter’s orbital energy and receive a 9,000 mph (14,400 km/h) speed boost in return.

The Jupiter encounter offers scientists a chance to learn more about the solar system’s largest planet. In this artist’s rendering, New Horizons soars past Jupiter as the planet’s volcanic moon Io passes between them.


On August 29, 2006, the spacecraft’s Long Range Reconnaissance Imager (LORRI) opened its launch-cover door and captured its first picture in space. The target was M7, an open star cluster in the constellation Scorpius.

“Our hope was that LORRI’s first image would prove not only that the cover had opened completely, but that LORRI was capable of providing the required high-resolution imaging of Pluto and Charon,” explains Andy Cheng, LORRI’s chief scientist. “Our hopes were not only met, but exceeded.”

LORRI was the last of New Horizons’ 7-instrument science suite to demonstrate its capabilities in space. The instrument will obtain the mission’s highest-resolution images.

NASA/JHUAPL/SWRI Jupiter’s cloud belts, storms, and moons caught LORRI’s eye September 4, 2006, when NASA’s New Horizons probe was still 181 million miles (291 million kilometers) away. The moons Io and Europa lie above and to the right of the circular black dots, which are their shadows cast on Jupiter’s stormy atmosphere.

Because Jupiter is so much brighter than Pluto will be, the New Horizons imaging team wanted to see how well LORRI would perform when using extremely short exposures. This image is the result of a 6-millisecond test.

NASA/JHUAPL/SWRI The New Horizons probe’s Long Range Reconnaissance Imager (LORRI) snapped the images in this mosaic February 10, 2007, when the spacecraft was still 18 million miles (29 million km) away from Jupiter. The spacecraft will be 12 times closer at its February 28 closest approach.

Already, the giant planet has loomed so large, it nearly fills the camera’s 1,024-by-1,024-pixel field of view. Features as small as 180 miles (290 km) can be seen.

Both the Great Red Spot and “Red Spot, Jr.” appear in this image. The Great Red Spot is on the planet’s lower left, on the planet’s limb. Red, Jr., appears at a slightly lower latitude on the planet’s opposite side, near its right limb.

NASA/JHUAPL/SWRI Following its Jupiter encounter and speed boost, New Horizons mostly sleeps. In late 2014, as it nears Pluto, the craft will awaken and begin its main mission.

ASTRONOMY: KELLIE JAEGER Jupiter looms large in this LORRI image from January 24, 2007. New Horizons was still 35 million miles (57 million km) away from the giant planet. Jupiter’s moons Ganymede (top right) and Io (right center) appear as well. Ganymede’s shadow is the black oval near Jupiter’s north pole.