Danielle Venton | The Verge

Mars and comets: a brief summary of this week’s sweetest space news

2014-12-17T16:25:21-05:00

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Space and planetary scientists are out in force this week at the annual meeting of the American Geophysical Union in San Francisco. The buzz centers on comets, especially on results from Rosetta, the first mission to orbit and land on a comet and Mars, where possible traces of methane-belching microbes have again been spotted. Here’s a round-up of some of this week’s science.

Philae in flight to 67P/Churyumov-Gerasimenko as seen from Rosetta. (ESA)

Still searching for Philae

Any hour, any day now, Rosetta-mission scientists expect to know where their lander is.

“The photos we need have been taken,” says Matt Taylor, project scientist with the European Space Agency. “They’re in a pipeline, we’re just waiting for them to come down now.”

“Almost every day it surprises us with new results.”Taylor and fellow members of the Rosetta team spoke today discussing early results. In November Rosetta’s lander Philae touched down on 67P/Churyumov-Gerasimenko comet, a duck-shaped ball of ice and dust 320 million miles from Earth. Despite failing to fire its harpoons, and bouncing twice before coming to rest in a shadowy canyon, Philae instantly began sending messages home to Earth. With only 60 hours of battery life, and unable to use its solar panels in shadow, Philae went on an experimental bonanza: sniffing, sampling, drilling, and recording the comet.

So far the findings have been fascinating, says Kathrin Altwegg, the lead scientist for ROSINA, the sensor aboard Rosetta able to sniff out chemicals and molecules. “I think we picked a really good comet. Almost every day it surprises us with new results.”

Altwegg and her team have begun to analyze the comet’s chemistry, which she says is more varied and richer in organic molecules than she expected. Other groups are analyzing its icy geology, with the suspicion that the lumpy comet is actually two comets melded together.

Rosetta mission selfie, with 67P in the background. (ESA/Rosetta/Philae/CIVA)

Why Comets Are Cool

Comets, and their drier compatriots asteroids, are holdovers from the ancient days of our solar system. Like a snapshot from the nursery, they might tell us what conditions were like in our planet’s early history.

Our planet’s water probably didn’t come from a cometThe start of life on Earth, about 3.8 billion years ago, coincides with a time when the planet was suffering heavy pummeling by asteroids and comets — the late heavy bombardment. Earth’s earliest oceans vaporized under the pelting. The delicate carbon-based molecules upon which life is built could not have survived. Yet, here’s a mystery: life, it seems, began just as soon as it could. Fossils appear rather quickly. The earliest date from 3.5 billion years ago. How did life find the needed water and carbon-based molecules on Earth’s surface?

Comets hold both water and carbon-based molecules. That makes them tempting targets for explaining how it was that life came to be — even though they also have wiped out a number of species. But the comet-as-nursery theory came under some pressure earlier this month, when Rosetta released its first results. The chemical signature from the comet’s water didn’t match the water on the Earth’s surface. Our planet’s water probably did not come from a comet — at least, not this type of comet.

Some space scientists think asteroids were a more likely delivery route or perhaps the water was made here all along. Two NASA missions, the already-launched Dawn and the upcoming OSIRIS-REx are hot on the pursuit of asteroids.

And we haven’t heard the last of Philae, according to Jean-Pierre Bibring, the lead lander scientist. Next February or March, as the lander gets just a little more light to power its solar panels, he expects it to wake up again. “I believe if we’re patient enough Philae will go beyond our expectations,” he says.

A shot of the first sample-collection hole drilled in Mount Sharp. (NASA/JPL-Caltech/MSSS)

Martian Methane Comes And Goes

Yesterday at the same meeting in San Francisco, NASA shared their latest findings from the Curiosity rover which has spent the last two years drilling, sniffing rocks and taking selfies on the surface of Mars.

Starting in late November 2013, Curiosity detected a spike in methane levels, nearly a 10-fold jump from low background levels. Methane remained abundant for about two months and disappeared as quickly as it arose. On Earth methane is usually a product of gas-burping microbes, so its presence raises hopes that Mars now or at one time hosted life.

mysterious methane“Methane on Mars is as much of a mystery as it’s ever been,” says John Grotzinger, the mission’s project scientist. This finding reverses a 2013 announcement by the team in which Curiosity found no methane gas. That surprised many since, in 2003, NASA reported spotting a Martian methane plume based on data from Earth-bound telescopes and spacecraft orbiting Mars.

“We knew that could happen, but you report what you find,” says Grotzinger. “We don’t know when it might pop up again, but we’ll keep monitoring.”

Although microbes would be most people’s favored source for the Martian methane, it isn’t a clear signal for life. It might also be the reaction product of water, rock-bound minerals, and ultraviolet radiation. At any rate, Grotzinger says he felt lucky to detect any methane at all.

“It’s not evidence that we’ve found life on Mars, but it is one of the few hypotheses we can propose and consider as we go forward,” says Grotzinger. “The fact that we saw anything is amazing.”

“a deductive line of science”Grotzinger and his team also announced proof of organic molecules in ancient rocks on Mars. Like methane, chlorobenzene can be created through non-living chemical reactions. It is still tantalizing, however, since organic molecules like these are what would be needed for life on or under the rocky red surface. In 2015, Grotzinger and his team plan to drill more holes and hunt for other organic signatures.

“Mars is turning the corner,” Grotzinger says. It used to be a planet where space missions would explore and seek to explain. I think of it as the Star Trek mode — build a spacecraft, find cool things that no one has ever found before. Mars is now becoming a proving ground for a more deductive line of science.”

As evidence he pointed toward NASA’s MAVEN mission. “They’re testing very specific hypotheses about how the atmosphere of Mars eroded,” he said. “We’re doing the same for Curiosity with these ancient rocks.”

Artist’s conception of the MAVEN spacecraft orbiting Mars. (Courtesy NASA/GSFC)

The MAVEN of the Skies

NASA’s Mars Atmosphere and Volatile Evolution spacecraft has been orbiting the planet since September. Its mission is to study what happened in Mars’ once-abundant atmosphere. The loss of atmospheric gas, as solar wind gradually chewed it away, completely transformed Mars. It was once a relatively wet, warm pleasant place. Now, it is a frozen wasteland of dry rock.

A visitor from the Oort cloudMAVEN’s team presented early results on Monday at the AGU meeting. The solar wind, a river of hot protons that flows from the sun, can penetrate deeper into Mars’ spare atmosphere than previously thought, they announced. The ionosphere, a protective layer of ions and electrons, should normally act as a shield to the solar wind. Yet MAVEN’s observation that some protons make it deep within that layer are “links in a chain” toward explaining Martian history, according to Bruce Jakosky, the mission’s lead scientist.

In October MAVEN, and the other orbiters and rovers that make up the Mars flotilla, survived a close call. The planet was buzzed by wayward comet “Siding Spring,” a visitor from the distant Oort Cloud. A Martian would have seen thousands of shooting stars per hour, researchers estimate. For the flyby Curiosity, which spends most of its time looking at the ground, glanced upward. It captured a few snapshots of its cometary visitor, much as an Earth-bound human might, staring in wonder at the night sky.

How did Orion withstand temperatures twice the melting point of steel?

2014-12-05T12:01:48-05:00

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An animation of Orion's return through the atmosphere | NASA

In Florida, at the Kennedy Space Center, Molly White is cheering with her sister. Today the two space enthusiasts watched gleefully as the Orion spacecraft rocketed away from Cape Canaveral, circled Earth twice, and splashed down off the coast of Baja California in the Pacific Ocean at 10:29AM Eastern. A product of years of work and anticipation, the uncrewed Orion Exploration Test Flight-1 took exactly 4 hours and 24 minutes. And White, an aerospace engineer for the National Aeronautics and Space Administration, was crucial to making it all work.

Molly White, left, and her sister Emma at the Kennedy Space Center causeway viewing area just before launch. (Image courtesy Molly & Emma White)

“It was indescribable,” she says. “The crowd got quiet during the countdown, we were all holding our breath, hoping nothing would go wrong. And when it went off it was so loud, so huge. It was just amazing.”

White is one of the many researchers responsible for Orion’s heat shield. This reflective, flammable blanket is crucial to the spacecraft’s ultimate mission: sending humans to Mars and bringing them back safely. It’s been White’s job since 2010 to predict temperature and airflow around the heat shield during takeoff and landing.

She’s been counting down to today for months. “These last few days have just been watching, waiting, and getting more and more excited,” she says. Yesterday, the intended launch was repeatedly delayed by stray boats, wind gusts, and technical problems — and that was “a bit of an emotional roller coaster,” she says. “It goes to show you so many things have to go right for a space launch – the weather, all of the systems, the rocket, as well as the payload.”

“I’ll be high off of this for a few weeks,” she says. Like a lot of kids, she wanted to work for NASA. As a little girl she admired her grandfathers, who were both engineers. In school she excelled in math and science and started to love space after a middle school project on the cosmos. She studied aerospace engineering, hoping to work on spaceflight. “Part of me thought it was a pipe dream,” she says, “something I’d never get to work on.”

The first day on her dream job was actually a let-down. On February 1, 2010 — her first day — NASA’s Constellation program, the George W. Bush-era plan to return humans to the moon via Ares I and Ares V rockets, was cancelled. “I had been brought on to help with Constellation, so I was a bit nervous,” White says. Her boss assured her though that something new and cool would be coming her way. She’s worked on Orion ever since.

the first day of her dream job at nasa was actually a let-down. the project she had been hired for was cancelled.

Today’s test flight is crucial for her to continue her work. After all the data is recovered White and her team will have a lot of work to do evaluating how well their predictions stacked against the harsh reality of space.

The largest-ever heat shield is installed on Orion. (NASA)

“There is a lot at stake for this flight test because we really need this data to refine our design and to know how the parts of Orion perform together,” White says. “We have our models and our simulations, and while we do the best that we can, there could be parts that we missed or didn’t know existed. You can’t know what you don’t know, right?”

NASA has sent humans beyond Earth many times, notably during 11 Apollo moon missions between 1968 and 1972. But Orion is to be the most ambitious crewed mission to date, representing a renewed hunger for space exploration. This spacecraft is meant to travel farther, faster, and carry more astronauts than ever before, and it’s hoped that Orion will be the safest space vehicle built to date. If all goes according to schedule, Orion will put humans on an asteroid by 2025 and on Mars in the 2030s. Here’s how crazy it all is: in June, a blue-ribbon panel issued a highly critical report, questioning whether the agency was currently on the right track. The congressionally charted Committee on Human Spaceflight suggested focusing more exclusively on reaching Mars. In response, NASA essentially yawned.

orion could put humans on an asteroid by 2025 and ON MARS IN 2030-2040

Orion bears a striking resemblance to the Apollo crafts, and that’s no mistake. “The theme of Orion is recreating Apollo with 21st century modern technology,” says John Balboni, an engineer at the NASA Ames Research Center. Balboni has worked in the arc jet test facility for the past 30 years, testing heat-shielding materials in a plasma wind-tunnel.

A view of Earth from Orion’s first orbit. (NASA)

“We can’t just reuse the old designs,” he says. The engineers who created materials such as the Apollo heat shield left documentation, but few of them are around anymore. “It’s like trying to make a cake from your grandmother’s recipe,” he says. “She could leave you all the ingredients and all the steps, but you’re not going to make a cake as good as your grandmother made.”

That’s not all. In the decades since the Apollo missions, new materials, such as high-temperature ceramics, have been invented and some old materials have been improved. Other components used years ago, such as asbestos, were phased out after they were found to be toxic. For Orion’s shield NASA redeveloped Avcoat, a combination of fiberglass and high-tech plastics, that was used, in an earlier form, for Apollo’s heat shield.

“IT’S LIKE TRYING TO MAKE A CAKE FROM YOUR GRANDMOTHER’S RECIPE.”

The shield is crucial to the success of the mission because getting humans into and home from deep space requires hurling them around as fast as possible. The faster a craft’s trip through the atmosphere, the more kinetic energy is transferred into heat. A capsule returning from the moon smacks into the atmosphere at about 25,000 miles per hour. The heat shield reaches about 5,000º F at this speed. If Orion makes the return journey from Mars someday, it’ll enter the atmosphere at an estimated 33,500 miles per hour, heating the heat shield to near 5,500º F. The air around it, as it travels in a plasma fireball, is about twice as hot as the surface of the sun.

That much heat puts intense stress on materials, and if your heat shield fails, the entire vehicle can be lost. “We’ve seen failures of the heat shield on the shuttle mission,” says White. “Hot gas was able to get inside the structure and cause things to explode and burn up.” In 2003, space shuttle Columbia disintegrated as some of heat-protective tiles failed just before landing, killing all seven crew members aboard.

Today, after saying goodbye to Florida, Orion sped through the atmosphere. On the surface of the craft, the noise was estimated to be about 100 times louder than a rock concert. Orion circled the earth twice, reaching as high as 3,600 miles on the second loop – 15 times higher than the International Space Station. When Orion slammed back into the atmosphere at 20,000 mph (about 30 times the speed of sound) the heat shield survived an estimated 4,000º F. If it worked as intended, about 20 percent of the shield burned up on the way down, further dissipating heat.

“the most perfect flight you could imagine.”

After about five minutes into its ride through the atmosphere, slowing down to about 300 mph, Orion began firing parachutes. These parachutes, 11 in total, unfurled in a multi-stage Kevlar-nylon ballet. With their help, Orion decelerated from 300 mph to just 20 mph in five minutes, slow enough for a graceful splashdown.

“It turned out to be the most perfect flight you could imagine,” said Rob Navias, NASA TV commentator as Orion splashed down.

The spacecraft is now floating in the water, soon to be recovered by two US Navy ships. The USS Anchorage will collect the crew module, while the salvage ship, the USNS Salvor, will recover jettisoned hardware like parachutes and the forward bay cover, which protects the upper part of the spacecraft.

I get a text from Molly just after the splashdown. “”We made it!!” she writes.

The precious data White wants is now bobbing in the Pacific, aboard the crew module. More than 1000 sensors aboard Orion recorded conditions during the flight: the stress, vibration, temperature, acceleration, pressure — all the crucial information to prepare for a flight that will include people. It’s been an exciting day for White. She and her team will spend the day basking in the glow of a successful test. But Monday she goes back to work. After all, Mars is still a long way off.