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Technology Why NASA is crashing the $4 billion Cassini spacecraft into Saturn

00:36  14 september  2017
00:36  14 september  2017 Source:   vox.com?utm_source=MSNbanner

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On Friday, September 15, around 7:55 am EDT, NASA will watch its 20-year-old, $ 4 billion -plus spacecraft to crash into Saturn . And that’s why Cassini ’s finale is so special: It’s not just a spectacle.

NASA /JPL-Caltech. On Friday, September 15, at 7:55:46 am Eastern time, NASA watched its 20-year-old, $ 4 billion -plus spacecraft crash into Saturn . That’s why Cassini ’s finale was so special: It’s not just a spectacle.

  Why NASA is crashing the $4 billion Cassini spacecraft into Saturn © Provided by Vox.com

For 13 years, Cassini has explored the gas giant and its moons. On Friday, it takes a final plunge into the planet.

On Friday, September 15, around 6:30 am EDT, NASA will watch its 20-year-old, $4 billion-plus spacecraft to crash into Saturn.

The space agency really has no other choice. Cassini is nearly out of fuel, and has already been stretched years beyond its intended mission duration. What’s more, keeping it going risks potentially contaminating one of Saturn’s moons — like Enceladus, an ice world that has some ingredients for life, or Titan, a dynamic moon where it rains methane — with microbes from Earth.

Cassini Captured Some Incredible Photos Of Saturn's Rings

  Cassini Captured Some Incredible Photos Of Saturn's Rings Last month Cassini took the most detailed photos of Saturn's rings that it has even captured.But before the craft performs its final act of science, it’s been completing several loops of the rings of Saturn. That science would have never been possible without the finale orchestrated the way it has been. So far it’s resulted in some stunning images of Saturn, some of which NASA released Thursday.

On Friday, September 15, around 7:55 am EDT, NASA will watch its 20-year-old, $ 4 billion -plus spacecraft to crash into Saturn . And that’s why Cassini ’s finale is so special: It’s not just a spectacle.

Further reading: Why NASA is crashing the $ 4 billion Cassini spacecraft into Saturn . One reason: to protect Saturn ’s moons — including Enceladus and Titan, environments that could potentially harbor life — from contamination via Cassini debris.

And so the spacecraft will end its existence by literally going where no human-made object has gone before: into Saturn’s atmosphere.

But up through its very last moments, Cassini will be conducting a scientific investigation. As it descends into Saturn’s atmosphere, several of its instruments will be on, including the mass spectrometer, which can essentially “sniff” the atmosphere and determine the chemical compounds therein.

Cassini has made discoveries that have changed our understanding of Saturn and the cosmos at large. The spacecraft discovered whole new moons around Saturn, lakes of methane on Titan, and jets of water erupting from Enceladus, and has made extremely detailed observations of the planet’s rings, an environment believed to be similar to the rings of debris that formed the entire solar system. But ending is bittersweet: Scientists have dedicated decades of work to the mission and the study of Saturn, and Cassini ends its run with some key Saturn mysteries still unsolved.

9 Essential Facts About Saturn

  9 Essential Facts About Saturn On September 15, scientists will intentionally crash the Cassini spacecraft into Saturn. Here are some essential facts about Saturn to get you ready for the big event.Mental Floss is going to be inside mission control at NASA's Jet Propulsion Laboratory in Pasadena, California, as the scientists send Cassini on its grand finale mission. We'll have a full dispatch for you. In anticipation, we spoke to Saturn experts to find out what you need to know about the planet before Cassini takes its final plunge.

NASA ’s Cassini spacecraft completed its mission to Saturn Friday morning — by crashing and burning straight into the planet. READ MORE: IN PICTURES: A look back at NASA ’s Cassini before its fiery end.

On Friday, September 15, around 7:55 am EDT, NASA watched its 20-year-old, $ 4 billion -plus spacecraft to crash into Saturn . The space agency really has no other choice. Cassini is nearly out of fuel, and has already been stretched years beyond its intended mission duration.

Cassini’s final days will be its most dramatic. Here’s what will happen.

The crash will be one last, spectacular moment in Cassini’s “Grand Finale”

For the past several months, Cassini has made 22 orbits in and out of the region between Saturn and its rings, a place where no spacecraft has gone before. There, Cassini made the careful measurements needed to assess the mass of the rings and ultimately determine their age (preliminary analysis suggests they’re younger than expected).

These harrowing inner-ring passes were saved for the very end of the mission, because NASA’s scientists didn’t know if there would be debris in this space that could have destroyed the craft. In fact, Cassini didn’t encounter much dust or debris in this space at all, which in itself is a new discovery about the Saturn system.

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  'Knocking on eternity's door' — NASA's Voyager mission turns 40 NASA’s Voyager mission celebrates 40 years in space this year, and humanity has much to thank it for. &nbsp;Voyager brought to Earth the first close-up views of Uranus and Neptune. It revealed "spokes" in the rings of Saturn and details of Jupiter’s storm that had never been seen or even imagined. It imaged Io’s volcanic plumes and found the potential for life on the moons Enceladus and Titan.

NASA 's Cassini spacecraft has been studying Saturn for two decades and is finally running out of rocket fuel, ending its mission in a blaze of glory by crashing into Saturn on September 15, 2017.

NASA 's Saturn -orbiting Cassini spacecraft . faces fiery finish. After a 20-year voyage, NASA 's Cassini spacecraft is poised to dive into Saturn this week to become forever one with Telescopes on Earth will watch for Cassini 's burnout nearly a billion miles (1.6 billion kilometers) away.

On September 11, a final pass-by of the moon Titan put Cassini on a collision course with Saturn (check it out in the animation below). Earl Maize, the project manager of the mission, called this pass “a kiss goodbye.” And it is goodbye. There is no way to stop the spacecraft from crashing now.

The mission’s scientists — many of whom have worked on Cassini since its inception in the 1980s — are overflowing with sentiment for the SUV-size craft.

“Our families have gotten to know each other, in some cases our children have grown up together, and now in the final two weeks we’re sharing the end of this incredible mission,” Linda Spilker, a Cassini project scientist, says. Cassini has spent 13 years orbiting Saturn. It has been in space for 20.

How Cassini will melt and explode in its descent into Saturn

There are some last orders of business for Cassini before it meets its demise. Its cameras are taking some final images of the moons Titan and Enceladus as well as a tiny moonlet in the rings that may soon leave the rings, and some final color images of Saturn itself. “These final images are like taking a final look at your house or apartment just before you move out,” Spilker says. “Memories across the years come flooding back.”

Where Are Our Nine Farthest Probes?

  Where Are Our Nine Farthest Probes? As Cassini prepares for its final plunge into Saturn's atmosphere, here is a look at our nine farthest scouts in the solar system and beyond.<br>The stunning images of Saturn’s rings that have been sent back by Cassini will always be a testament to the brave plunges the little explorer took into the untouched parts of the cosmos leading up to the final plunge.

Science. NASA is crashing Cassini into Saturn on Friday — here's what will happen in the probe's final hours, minutes, and seconds. An artist rendering of NASA 's Cassini spacecraft observing a sunset through the hazy atmosphere of Titan, Saturn 's largest moon.

On Friday, NASA 's Cassini spacecraft will nose-dive into Saturn and burn up in the planet's atmosphere. First, a brief bio: Cassini launched on its billion -mile journey from Earth to Saturn on Oct.

Starting on September 14, Cassini will turn back to Earth, secure a good radio connection, and reconfigure itself to become a makeshift atmospheric probe.

When it moves through empty space, Cassini meets no resistance. So it’s easy to keep flying without deviations. But once it hits an atmosphere, everything changes. As with the wind resistance you feel when sticking a hand out of a moving car’s window, Cassini will begin to wobble it gets deeper into the atmosphere.

There, the craft’s oddly shaped radio equipment and magnetic will catch like sails, throwing Cassini into a tumble. It has few small thrusters designed to counter the tumbling motion, but they weren’t designed to for planetary entry.

At first, those thrusters will fire intermittently to keep Cassini’s transmitter pointed toward Earth. Then “it will get to the point where the thrusters will turn on, 100 percent, trying to fight the atmosphere,” Thomas Burk, a NASA Jet Propulsion Lab engineer who has worked on the mission from the beginning, says. “Of course, it will lose that battle.” In all, Cassini may stay stabilized for just two minutes after it enters the atmosphere.

Once Cassini starts to tumble, it will no longer be able to send data back to Earth. From NASA’s perspective, that’s the end of the mission.

Where Are Our Nine Farthest Probes?

  Where Are Our Nine Farthest Probes? As Cassini prepares for its final plunge into Saturn's atmosphere, here is a look at our nine farthest scouts in the solar system and beyond.<br>The stunning images of Saturn’s rings that have been sent back by Cassini will always be a testament to the brave plunges the little explorer took into the untouched parts of the cosmos leading up to the final plunge.

They plan to squeeze every last byte of data they can from the robot, right up until Cassini turns into a brilliant radioactive comet above the swirling storms of Saturn . Reasons behind NASA ’s decision of crashing Cassini : The Cassini spacecraft has been in orbit around Saturn since 2004 and the

The last photos NASA 's Cassini spacecraft ever took were of its own grave. Credit: NASA /JPL-Caltech/ Space Science Institute. Why are there no images from today, during the plunge itself? Editor's Recommendations. Cassini 's Saturn Crash 2017: 'Grand Finale' at the Ringed Planet.

But Cassini will live on in tumultuous silence for at least a few more minutes, traveling at around 20 miles per second. The forces from the tumbling will literally rip its components apart, piece by piece.

Then it will melt, and explode. “The outer surface materials might start to char at first; then you’d see some breaking apart; then when you get down to the metal, once it gets hot enough, it will glow,” says Brett Pugh, a NASA JPL thermal engineer. There’s no oxygen on Saturn, so there’s no fire. But “the propellant tanks will explode eventually as the temperatures get high enough,” he says.

That might produce a flash, like the streak of light that explodes from a meteor above Earth. (NASA will point some telescopes at Saturn to watch, but they’re unlikely to see anything.) After the tanks explode, there will be nothing left. “It would be a tremendous view, if anyone could witness it,” Pugh says.

As NASA spokesperson Preston Dyches has said: “We’re going out in a blaze of glory.”

NASA An artist’s depiction of Cassini breaking apart as it descends into Saturn’s atmosphere.

Whatever’s left will continue to sink deeper and deeper into Saturn’s atmosphere, “where intense heat and pressure will cause all of its materials to melt and completely dissociate, eventually becoming completely diluted in the planet’s interior,” NASA explains. The trace bits of metal, composite materials, and even some of the plutonium that powers Cassini will become undetectable in the planet, which is 764 times the size of Earth.

Cassini has completely transformed our understanding of Saturn

Cassini — named after the 17th-century astronomer Giovanni Cassini — launched from Cape Canaveral in October 1997 in a NASA collaboration with the European Space Agency. At that time, we were still a few months away from Bill Clinton’s damning “I did not have sexual relations with that woman” remark. Harry Potter had not yet been published in the United States.

Cassini, NASA's 13-year Saturn mission, has ended

  Cassini, NASA's 13-year Saturn mission, has ended Contact has been lost with the Cassini spacecraft after it completed a "death dive" into the upper atmosphere of Saturn and transmitted its final signal, according to NASA. The spacecraft deliberately sank into Saturn's upper atmosphere at a high speed and plunged itself into the planet just after 6:30a.m. ET Friday. Given the amount of time it takes signals to reach Earth, the final signal and last bits of data reached the Deep Space Network's Canberra Station in Australia about an hour and a half later. NASA confirmed the spacecraft's demise at 7:55 a.m. ET, as predicted.

NASA 's Cassini spacecraft disintegrated in the skies above Saturn on Friday in a final, fateful blaze of cosmic glory, following a remarkable journey of 20 years. Scientists wanted to prevent Cassini from crashing into Enceladus or Titan—and contaminating those pristine worlds. And so in April, Cassini

But why crash Cassini into Saturn ? NASA decided to incinerate the probe to ensure that it doesn't careen into , and potentially contaminate, Titan or the fellow Saturn moon Enceladus, both of which may be capable of supporting life.

From there, it took Cassini, and the Huygens probe (destined to touch down on the moon Titan), seven years to reach Saturn. Once it arrived, it started to make discoveries that utterly changed our understanding of the planet and its system.

On Titan, Cassini and Huygens revealed surprisingly earthlike geographic features and huge lakes of liquid natural gas on the moon’s surface that outweigh all the oil and gas reserves on Earth. There are great clouds on Titan that rain down liquid methane. There are rivers of it on the surface.

Cassini found evidence of an underground ocean on the moon Enceladus, an incredible discovery. It learned those oceans may contain hydrothermal vents and the right ingredients to support life. Like the geothermal vents deep within Earth’s oceans, these could be home to microbes that use the chemical energy of hydrogen and carbon dioxide to produce methane and energy. And Cassini regularly sees great plumes of water vapor and gases erupt from the surface of Enceladus.

“Enceladus may have all the ingredients for life — as we know it — to currently exist,” Curt Niebur, a Cassini program scientist, told reporters at a recent press conference. The discovery of the ocean “changed our idea that ocean worlds — like Earth and Europa — are rare in the universe,” he said.

Cassini learned how new moons could form out of Saturn’s rings. And it has taken detailed photographic surveys of the planet’s rings and surface features — like the beautiful hexagonal cloud patterns bigger than Earth that exist at the North Pole.

Cassini’s last look at Saturn will be our last look at the planet for at least a generation

When the spacecraft sends the last image of Saturn back to Earth on Friday, it will be the last time our human eyes will get to see Saturn up close for many years. There are no upcoming missions planned for the Saturn system. A new one could take a decade to plan and launch, and then it takes about seven years to reach the planet.

NASA’s next big planetary science effort is the Europa Clipper, which will launch in the 2020s. Its goal is to investigate Jupiter’s ice moon.

So for all we know, this is the last chance NASA has to make direct measurements of Saturn, its atmosphere, and its vexing and beautiful rings for a very long time.

And that’s why Cassini’s finale is so special: It’s not just a spectacle. It’s a scientific operation that honors the precious limited time we have to explore other worlds. And that pain is compounded by the fact that Cassini leaves Saturn with mysteries left unsolved.

Scientists still don’t know exactly how quickly Saturn’s core rotates, which would determine the length of a Saturn day. This is a huge, basic question about the planetary system, and it will remain unanswered, for now. And scientists still don’t have an exact figure on the mass of Saturn’s rings or their age.

“It’s been part of my life for so long, this spacecraft, it’s going to be a shock to have this happen,” Burk says, anticipating the moment Cassini goes offline. “It’s bittersweet in that regard. But it’s a really exciting ending. When we stop getting data, that will be the moment of truth.”

Spaceship chasing an asteroid to slingshot past Earth .
<p>A spaceship will swing by Earth on Friday and use our planet's gravity to help it pick up speed on its way to explore an asteroid.</p>NASA's OSIRIS-REx will fly about 11,000 miles (17,000 kilometers) above Antarctica at 12:52 p.m. ET.

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