New Horizons images enable first test of interstellar navigation
Illustration by NASA New Horizons Spacecraft artist in the outdoor solar system
Joe Olmsted / STSCI
As it comes out of our solar system, the NASA New Horizons spaceship is so far from the earth that the stars of the Milky Way appear in clearly different positions compared to our own point of view. Astronomers have now used this change of perspective to determine the position of the probe in the galaxy, in the very first example of interstellar navigation.
New Horizons was launched in 2006, initially to study Pluto, but it has since traveled far beyond this point, plowing the Kuiper belt, a large and wide strip of rocks and dust to billions of kilometers from the sun. It now accelerates tens of thousands of kilometers per hour.
Looking at the night sky of the earth, the stars are so far that they do not seem to change position when they are seen from different places, unless you have a powerful telescope. But from the point of view of New Horizons, there is a significant change in the positions of the stars due to the parallax effect. This was demonstrated in 2020 when the probe radiated photos of two nearby stars, Proxima Centauri and Wolf 359, at Earth.
Now Tod Lauer at the National Laboratory of National Research on Optical Infrared Astronomy in Arizona and his colleagues used this effect to determine the position of the New Horizons. They did it by comparing the photos of the proxima Centauri and Wolf 359 probe with measurements of the Gaia space telescope, which produced the most detailed map of the stars on our Milky Way.
“We have a fairly good three -dimensional card of the galaxy around us that you can know where you are,” explains Lauer. “This is a remarkable precision, with your own camera [on board a spacecraft]. “”
To calculate the position of the space machine, he and his team looked at the position of the stars while they appeared from the on -board camera from New Horizons, bringing a line of view of the two stars and working where the two lines were closest. Then they used the precise position of the two stars of the Gaia stars map to determine where this point was compared to the solar system.
This two -picture animation shows the changing position of Proxima Centauri, seen from the earth and New Horizons
Almost all space vessels calculate their bearings less than tens of meters using the depth network of NASA (DSN), a collection of radio transmitters on Earth which send regular signals to space. In comparison, the parallax method was much less precise, locating new horizons in a sphere with a radius of 60 million kilometers, about half of the distance between the earth and the sun.
“We are not going to keep the Deep Space network sheltered from business – this is only evidence of demo,” explains Lauer. However, with better camera and better equipment, they could improve precision up to 100 times, he said.
The use of this technique for interstellar navigation could offer advantages compared to the DSN, because it could give more precise location readings as a spacecraft moves away from the earth, while being able to operate independently without having to wait for a radio signal from our solar system, explains Massimiliano nasile at the University of Strathclyde, in the United Kingdom.
“If you travel to a real star, we are talking about light years,” says Vasile. “What is happening is that your signal from the deep space network must travel all the way and then back, and it moves at the speed of light, so it takes years.”
However, there are no ongoing missions to go deep into interstellar space by an agency, known as vasile, so the usefulness of this particular technique is limited until we take shape, he says.
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