The most distant spacecraft in the solar system

Humans have been tossing things into deep space for 50 years now, since the launch of Pioneer 10 in 1972, and we now have five spacecraft that have either reached or are rapidly approaching the edges of our solar system: Pioneer 10, Pioneer 11, Voyager 1, Voyager 2, and New Horizons.

Most of these investigations have defied predictable fatalities and are still operating long after their original mission plans. These spacecraft were originally planned to explore our neighboring planets, but now they’re making their way out Solar Systemproviding astronomers with unique perspectives into space — and they’ve come a lot in 2022.

Travelers 1 and 2

the Voyager Expeditions celebrated a very special anniversary this year: 45 years of operations. From close flybys of exoplanets to far-reaching explorations for humans in space, these two spacecraft have contributed greatly to astronomers’ understanding of the solar system.

Their main project now is to explore where the sunHis influence ends, and the influences of other stars begin. Voyager 1 It crossed the heliosphere, the boundary at which the influx of sun particles ceased to be the most significant influence, in 2012 with Voyager 2 After closing in 2018.

“Now Voyager 1 has been in interstellar space for a decade…and it’s still going, and it’s still going strong,” Linda Spilker, Voyager project scientist and planetary scientist at NASA’s Jet Propulsion Laboratory (JPL) in California, told Space.com.

The mission team hit a major bump this year, when the spacecraft was launched Send garbled information home about its location. Engineers found the reason – the spacecraft was used Bad piece of computer hardware When he does not have – and restore operations.

These types of accidents can be expected with an aging spacecraft. The team is also actively managing the power supply on board each spacecraft, which dwindles each year as the probe’s radioactive generators get more efficient. This year, mission personnel turned off the heaters that keep a number of science instruments on board warm in the harsh, cold space environment — and to everyone’s surprise, those devices are still working just fine.

Farthest human spacecraft and trajectories out of the solar system, far from Earth. (Image credit: NASA/Johns Hopkins APL/Southwest Research Institute)

The cameras may have been turned off decades ago, but the spacecraft’s other instruments collect data on plasma and magnetic fields from the Sun at a great distance from the star itself. Because molecules solar wind – The constant stream of charged particles streaming out from the sun – takes a long time to travel such a long road, distant observations allow scientists to see how changes from the sun spread throughout our cosmic neighborhood.

The edges of the solar system were full of surprises, too. It might make sense that the plasma from the sun would become rarer and spread out the farther from the center of the solar system, but in reality, Voyagers encountered denser plasma after crossing the heliosphere. Astronomers are still baffled.

“It’s absolutely amazing that even after all this time we continue to see the Sun’s influence in interstellar space,” said Spilker. “I look forward to Voyager continuing to operate, and possibly reaching its 50th anniversary.”

Pioneers 10 and 11

The Pioneer spacecraft holds a special place in space history because of their role, you might guess, as pioneers. Unfortunately, these 50-year-old spacecraft are not working – Pioneer 10 Contacts were lost again in 2003, and Pioneer 11 She has been silent since her last contact in 1995.

But both spacecraft are signs of humanity’s presence in the solar system, and they continue their journeys, even if we don’t send them orders or launch their rockets anymore. Once a spacecraft is set on a trajectory outside the solar system, according to the laws of physics, it will not stop unless something changes its trajectory.

new Horizons

New Horizons is by far the younger sibling of these groundbreaking missions, and it has just that It was launched in 2006. After completing the file A famous flyby of the dwarf planet Pluto in 2015This probe has zoomed out of the solar system at record speed and is scheduled to reach the heliosphere around 2040.

It not only completed its primary mission, but also successfully completed its flyby of the Smaller Kuiper Belt Object. Arrokoth, in 2019 as its first mission extension. Earlier this year, the spacecraft was put into hibernation because the extended mission had not yet been approved. But now, the team is excitedly moving on to New Horizons’ second Kuiper Belt Expanded Mission, or KEM2 for short. KEM2 started on October 1stalthough the spacecraft will enter hibernation until March 1, 2023.

Meanwhile, the expedition team prepares for exciting new observations. With state-of-the-art instruments — far more advanced than what Voyager carried in the 1970s — the team is poised to use New Horizons as an energy observatory in the distant solar system, providing a viewpoint we can’t achieve here. Land.

Bonnie Buratti, a planetary scientist at the Jet Propulsion Laboratory and member of the New Horizons team, is particularly looking forward to new views. Kuiper belt Bodies (KBOs), pieces of ice and rocks behind Neptune. She said New Horizons’ unique location in the outer solar system provides new angles for looking at these Kuiper Belt objects. The different views can tell astronomers how rough the surfaces of objects are, among other things, based on how light scatters and casts shadows on them.

Another planetary scientist on the team from the Southwest Research Institute in Colorado, Leslie Young, wants to use the spacecraft to take a fresh look at something closer to home: ice giants, Uranus and Neptune. New Horizons’ unique view provides scientists with information about how light is scattered through the planet’s atmospheres–information we can’t get from here on Earth, since we can’t see Uranus and Neptune from that angle. Planetary scientists are eager to get more information about these planets, especially as NASA begins planning a new mission to visit Uranus.

When the spacecraft wakes up from hibernation, it will traverse the so-called “Kuiper Shelf,” where scientists currently believe there are far fewer large Kuiper belt objects. “When we look at other star systems, we see disks of debris extending out to distances much greater than their host stars,” Brian Holler, an astronomer at the Space Telescope Science Institute in Baltimore, told Space.com. “If an ET looked at our solar system, would they see the same thing?”

This next expanded mission will venture beyond New Horizons’ original field of planetary science. Now, the spacecraft will provide better-than-ever measurements of the background light and cosmic rays in space, track the distribution of dust throughout our solar system, and obtain important information about the Sun’s influence, complementing Voyagers. Because the three functionally distant spacecraft point in separate directions, it allows astronomers to plot irregularities in the solar system’s structure.

Fortunately for New Horizons, indications are that the spacecraft will be powerful enough to last into the 2040s and possibly beyond — each year, moving 300 million miles (480 million kilometers) into uncharted territory.

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