NASA/JPL-Caltech
NASA/JPL-Caltech

Voyager 1's Back Thrusters Just Fired Up for the First Time in 37 Years

NASA/JPL-Caltech
NASA/JPL-Caltech

Imagine trying to start a car that's been sitting in a garage for decades—and the car is 13 billion miles away. That's what NASA attempted to do this week with the Voyager 1 spacecraft—and it worked.

Four of the thrusters on Voyager 1—the only human-made object ever to reach interstellar space—have been dormant since 1980, just three years after it and its twin probe, Voyager 2, were launched into the universe bearing the sights, sounds, and music of Earth on the Golden Record.

For the past 40 years, Voyager 1 has been using "attitude control thrusters" to keep the spacecraft's antenna oriented to Earth so that it can communicate with us, and us with it. The thrusters fire tiny pulses lasting for just milliseconds. For the past three years, they've been degrading, worrying the Voyager team.

Propulsion experts Carl Guernsey and Todd Barber, from NASA's Jet Propulsion Laboratory in Pasadena, California, considered different interventions and how the spacecraft might respond to them. They proposed attempting to start the four "trajectory correction maneuver," or TCM, thrusters located on the back of the spacecraft, hoping they could take over the job of correctly orienting Voyager. In the early days of the mission, these thrusters, identical in size and functionality to the attitude control thrusters, were used to keep the probe's instruments targeted on Jupiter, Saturn, and their moons as the spacecraft flew by them.

They pored over decades-old data and deciphered outdated software code to make sure they could attempt to turn on the TCM thrusters without causing damage to Voyager. Then, on Tuesday, engineers fired them up and tested their ability to orient the spacecraft, using 10-millisecond pulses. They had to wait 19 hours and 35 minutes for the data to make it to Earth, but eventually they got the good news: The TCM thrusters were up to snuff.

Now that the back thrusters are operational, Voyager 1 just got another two to three years of life, Suzanne Dodd, mission project manager at NASA's Jet Propulsion Laboratory, said in a statement. The plan is to shift the orientation work to the TCM thrusters in stages beginning in January. Each requires a heater to operate, and turning on the heaters requires power, which is a strain on the aging probe. So when there's no longer enough power for them, the job will switch back to the attitude control thrusters.

The engineers will likely attempt the same move with Voyager 2 when its attitude control thrusters start to break down; currently, they're in better shape than Voyager 1's. Now in the periphery of our solar system in what's known as the heliosheath, Voyager 2 will enter interstellar space in the next few years. As the twin crafts fly deeper into the universe at more than 36,000 mph, they'll keep talking to Earth for at least a little while longer. 

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NASA Has a Plan to Stop the Next Asteroid That Threatens Life on Earth
iStock
iStock

An asteroid colliding catastrophically with Earth within your lifetime is unlikely, but not out of the question. According to NASA, objects large enough to threaten civilization hit the planet once every few million years or so. Fortunately, NASA has a plan for dealing with the next big one when it does arrive, Forbes reports.

According to the National Near-Earth Object Preparedness Strategy and Action Plan [PDF] released by the White House on June 21, there are a few ways to handle an asteroid. The first is using a gravity tractor to pull it from its collision course. It may sound like something out of science fiction, but a gravity tractor would simply be a large spacecraft flying beside the asteroid and using its gravitational pull to nudge it one way or the other.

Another option would be to fly the spacecraft straight into the asteroid: The impact would hopefully be enough to alter the object's speed and trajectory. And if the asteroid is too massive to be stopped by a spacecraft, the final option is to go nuclear. A vehicle carrying a nuclear device would be launched at the space rock with the goal of either sending it in a different direction or breaking it up into smaller pieces.

Around 2021, NASA will test its plan to deflect an asteroid using a spacecraft, but even the most foolproof defense strategy will be worthless if we don’t see the asteroid coming. For that reason, the U.S. government will also be working on improving Near-Earth Object (NEO) detection, the technology NASA uses to track asteroids. About 1500 NEOs are already detected each year, and thankfully, most of them go completely unnoticed by the public.

[h/t Forbes]

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Frederick M. Brown, Getty Images
Stephen Hawking’s Memorial Will Beam His Words Toward the Nearest Black Hole
Frederick M. Brown, Getty Images
Frederick M. Brown, Getty Images

An upcoming memorial for Stephen Hawking is going to be out of this world. The late physicist’s words, set to music, will be broadcast by satellite toward the nearest black hole during a June 15 service in the UK, the BBC reports.

During his lifetime, Hawking signed up to travel to space on Richard Branson’s Virgin Galactic spaceship, but he died before he ever got the chance. (He passed away in March.) Hawking’s daughter Lucy told the BBC that the memorial's musical tribute is a “beautiful and symbolic gesture that creates a link between our father's presence on this planet, his wish to go into space, and his explorations of the universe in his mind.” She described it as "a message of peace and hope, about unity and the need for us to live together in harmony on this planet."

Titled “The Stephen Hawking Tribute,” the music was written by Greek composer Vangelis, who created the scores for Blade Runner and Chariots of Fire. It will play while Hawking’s ashes are interred at Westminster Abbey, near where Isaac Newton and Charles Darwin are buried, according to Cambridge News. After the service, the piece will be beamed into space from the European Space Agency’s Cebreros Station in Spain. The target is a black hole called 1A 0620-00, “which lives in a binary system with a fairly ordinary orange dwarf star,” according to Lucy Hawking.

Hawking wasn't the first person to predict the existence of black holes (Albert Einstein's general theory of relativity accounted for them back in the early 1900s), but he spoke at length about them throughout his career and devised mathematical theorems that gave credence to their existence in the universe.

Actor Benedict Cumberbatch, a friend of the Hawking family who portrayed the late scientist in the BBC film Hawking, will speak at the service. In addition to Hawking's close friends and family, British astronaut Tim Peake and several local students with disabilities have also been invited to attend.

[h/t BBC]

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