15 years after launching from Earth at record speed, New Horizons is on the verge of reaching a new milestone in the flight distance that only four other probes have crossed.
At 8:42 a.m. on April 18, Hanoi time, New Horizons will fly 50 astronomical units (AU), or 50 times the distance between Earth and the Sun (7.5 billion km). At this distance, the ship will take over 6.5 hours to transmit signals to Earth while traveling at the speed of light.
New Horizons is the fifth longest flying spacecraft on Earth. The Pioneer 10 launched in 1972 was the first probe spacecraft to cross the asteroid belt and fly over Jupiter, reaching a distance of 50 AU on September 22, 1990. Currently, the ship is located approximately 129 AU from Earth. Its junior model, the Pioneer 11, hit the 50 AU mark a year later, in 1991. The ship was launched in 1973. In addition to flying over Jupiter, it was the first probe to directly observe Saturn. Currently, the vehicle has stolen 105 AU from our planet.
NASA launched Voyager 1 on September 5, 1977, 16 days after the launch of its twin, Voyager 2. Voyager 1 studied Jupiter and Saturn, while Voyager 2 explored Uranus and Jupiter. Currently Voyager 1 and Voyager 2 are located 152 AU and 127 AU from Earth, respectively. Unlike the Pioneer 10 and Pioneer 11 which went out of business a few years ago, the Voyager duo still exists. At this time, neither the Pioneer nor Voyager ships are near New Horizons. Its closest probe is NASA’s Juno spacecraft.
To highlight the distance Voyager 1 traveled, NASA pointed the ship’s camera at the inner edge of the solar system when it was about 40.11 AU from Earth. The result, titled “Family Portrait”, shows six planets including Venus, Earth, Jupiter, Saturn, Neptune and Uranus. However, at a distance of 50 AU from the Sun, New Horizons could not do this.
“The algorithm shows that this activity will burn the camera because we are pointing it at the Sun,” said Alan Stern, principal investigator for the New Horizons project at the Southwest Research Institute in Boulder, Colo. “Even at such a great distance, the Sun is too bright for a long-range camera, which is calibrated to accommodate Pluto’s faint light. So we won’t do it until now. Crossing the Kuiper Belt after many years. Instead, Stern and his colleagues headed to New Horizons and the Voyager 1 side, marking the first time that a spacecraft in the Kuiper Belt had photographed the location of another ship moving through the interstellar space.
The 50 AU mark means the New Horizons vessel has exceeded its expected life. New Horizons flew over Pluto, returning a close-up image of the planet with its moons in July 2015, when the ship was 39.2 AU from the Sun. Researchers hope they can find another target before the New Horizons ship runs out of fuel. Despite taking power from nuclear batteries, the ship’s plutonium supplies are generating 33 watts less each decade. In the late 2030s, when New Horizons stole nearly 100 AU from the Sun, it may have too little fuel left to operate.