As the New Horizons spacecraft ejects into interstellar space, it has now reached a historic milestone. On April 17, 2021, New Horizons passed 50 astronomical units, or 50 times the Earth’s distance from the sun. These are just the 5de spacecraft to reach that distance, joining the Voyagers 1 and 2 and the Pioneers 10 and 11.
“Although four other missions reached this distance in the 20th century, no one was healthy, but New Horizons was,” said New Horizon chief investigator Alan Stern. on Twitter. “It’s a wonderful testament to the skill, care and attention to detail of those who designed and built New Horizons, and those who have been the flight crew for over 15 years now.”
This summer it will be six years since New Horizons flew with Pluto and its system of moons in July 2015.
To celebrate the achievement of reaching this new distance marker, scientists sent instructions to New Horizons a few months ago to try to image the location of another deep space traveler, Voyager 1, which is now in interstellar space. Although Voyager 1 is far too faint to be seen directly in the image, its location is known precisely because of NASA’s radio tracking.
“It’s a ghostly image to me,” Stern said.
The conversion of the AU scale to one with which we are more familiar, New Horizons is now almost 7 billion kilometers (7.5 billion kilometers) away. This means that it takes a lot of time to communicate with the spacecraft
At the time of the Pluto flight, two-way communication between New Horizons and Earth required a nine-hour return – 4.5 hours to the spacecraft and another 4.5 back. Because radio signals travel at a light speed (186,000 miles per second, 300,000 km per second), it illustrates Pluto’s great distance from Earth, nearly three billion miles (4 billion km). And at its current distance, the signals take 7 hours to reach the distant spacecraft, and another 7 hours before its control team on earth finds out if the message was received.
“Working so far away with a spacecraft is a challenge,” Alice Bowman told me in 2016 for my book “Incredible Stories From Space.” Bowman is the operations manager of New Horizons at the Johns Hopkins Applied Physics Laboratory, where New Horizons is built and operated. ‘I always say that you have to have a split personality when working in ops (Missions Operations) because of all the time changes. If you send a real-time mission from Earth, you need to know where the spacecraft will be in the future. ‘
The New Horizons team gave a different way of thinking about how far 50 AU is: Think of the solar system located in a neighborhood; the Sun is one house to the left of ‘house’ (or Earth), Mars would be the next house on the right, and Jupiter would be just four houses on the right. New Horizons would now have 50 houses in the street, 17 houses beyond Pluto.
New Horizons is by no means finished with its mission. After the Pluto flight over, on New Year’s Day 2019, the spacecraft first looked closely at a Kuiper Belt object (KBO) with its flight over Arrokoth. From its unique seat in the Kuiper Belt, New Horizons makes observations that can be made from anywhere else, even the stars look different from the point of view of the spacecraft.
New Horizons has collected data on the solar wind and space environment in the Kuiper Belt and searched for other Kuiper Belt objects, with a view to visiting one that appears along the road, within fuel reach. Stern said on Twitter. This summer, the mission team will launch a software upgrade to advance the scientific capabilities of New Horizons. For future exploration, the spacecraft’s nuclear battery should provide enough power to operate New Horizons until the late 2030s.
Further reading and more images: JHUAPL
