Scientists hope Japanese probe can answer questions about planet Venus

By Kenneth Chang

Venus is not a placid paradise — that much we know. In addition to searing surface temperatures, wind in the upper atmosphere howls as fast as 250 mph, carrying clouds around the planet once every four days.

Yet Venus itself spins very slowly: one rotation every 243 Earth days — in the wrong direction, no less, opposite to almost every other body in the solar system.

On the whole, the atmosphere on Earth rotates about the same speed as the planet. So why does the air on slow-spinning Venus speed around so much faster than the planet itself?

The Japanese space probe Akatsuki, now in orbit around Venus, seeks to solve the mystery of so-called super-rotation.

That is not just an idle trivia question for planetary scientists. Computer models of our own weather fail when applied to Venus, and knowledge of the planet’s workings could better our understanding of Earth’s.

‘‘We don’t know what is the missing point in meteorology,’’ said Masato Nakamura, Akatsuki’s project manager.

In recent years, Venus has been a backwater of planetary exploration, even though it is much closer in size to Earth than is Mars. For a long time, scientists imagined there could be a habitable tropical paradise beneath Venus’ thick clouds.

In the late 1950s, intense thermal emissions, measured by a radio telescope on Earth, told a different story. Venus broils.

The average surface temperature is more than 850 degrees — an extreme demonstration of the heat-trapping prowess of carbon dioxide, the primary constituent of the Venusian atmosphere. Clouds of sulfuric acid make it an even less appealing place to visit.

In the 1990s, NASA’s Magellan spacecraft precisely mapped the topography of Venus through radar. Except for a few flybys by spacecraft on the way to somewhere else, NASA has not returned to Venus, although the agency is considering two modest proposals.

A European mission, Venus Express, studied the planet from 2006 to 2014, discovering among other things a frigid layer of atmosphere, minus 280 degrees Fahrenheit at an altitude of 75 miles, sandwiched between two warmer layers.

But now Akatsuki, which entered orbit last December, has begun its work. Takehiko Satoh, one of the mission scientists, said that one of ‘‘the most exciting, most surprising results’’ so far came almost immediately after the spacecraft arrived.

The camera that captures long-wavelength infrared light from the cloud tops discovered an arc-shaped white streak that stretched 6,000 miles from nearly the south pole to nearly the north pole.

Curiously, this giant atmospheric feature does not move with the atmosphere. ‘‘It seems to be fixed to the ground,” Satoh said.

The arc sits above Aphrodite Terra, a highland region about the size of Africa that rises up nearly 3 miles from the surface. Scientists working on data from the Venus Express reported a similar finding in July.The small spacecraft — the main body is a box a bit bigger than a refrigerator — carries five cameras, collecting light at different wavelengths to monitor the Venusian atmosphere at different altitudes.

In another experiment, scientists will observe how the radio signal from the spacecraft to Earth is distorted when it passes through the atmosphere. That will reveal temperature, abundance of sulfuric acid vapor and other properties. By observing the atmosphere at different altitudes, they can detect wavelike features that rise and fall, like blobs in a lava lamp.That Akatsuki, which means ‘‘dawn’’ in Japanese, is there at all is the result of ingenuity and perseverance.

It launched in May 2010 and arrived at Venus seven months later. But when its main engine failed to fire properly, it sailed right past the planet. ‘‘It was a very sad moment,’’ Satoh said.

Within a day, Satoh said, calculations indicated that in six years, Akatsuki, in orbit around the sun instead of Venus, could meet up with Venus again. But it was not clear the spacecraft still would be able to slow down and enter orbit.

An investigation found that a valve in the engine had leaked, leading to the formation of salts that fused it shut. The engine, as it fired, had overheated beyond repair.

Akatsuki still had the maneuvering thrusters that were to be used after it entered orbit. They were not as powerful as the broken engine, but they could apply enough force to slow it down enough so that Venus’ gravity could capture it.The Akatsuki’s orbit is different from the one originally envisioned. Instead of being synchronized to the spinning atmosphere, which would have allowed scientists to better track small changes, the spacecraft now loops around Venus in a large elliptical orbit.

That provides different benefits. Instead of intently staring at one spot, seeing the smallest changes, scientists are now able to see what happens on a global scale, although they will miss some of the details.

Akatsuki is to continue operating until at least April 2018, depending on how much fuel it has left. ‘‘We know at least we have one kilogram of fuel,’’ said Nakamura, likening the uncertainty to an imprecise fuel gauge in a car.

If it turns out that Akatsuki has more, the spacecraft could continue operating for perhaps up to six years, he said.

 


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NASA Plans to Light a Fire Inside a Spacecraft, Then Watch What Happens

Relax, it’s being done for science.

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A flame in space, as photographed during a BASS (Burning and Suppression of Solids) experiment. (NASA)

AIRSPACEMAG.COM

For the past couple of weeks, on and off, astronaut Tim Kopra has been playing with fire on the International Space Station—part of an experiment called Burning and Suppression of Solids—Milliken (BASS-M), to test how flame-retardant cotton fabrics burn in microgravity.

Why? Because fire behaves differently in space than it does on Earth. In normal gravity, hot gas rises, drawing in cool, fresh air at the base of the flame. That’s what gives flames their familiar teardrop shape. In microgravity, hot gas doesn’t rise, so flames tend to be wider, shorter, and rounder than on Earth. As a result, flames in space radiate heat differently than they do on Earth, which in turn affects how fires spread. That means materials may be more or less flammable in orbit than they are on Earth, even with the same mix of atmospheric gases.

When it comes to flammability tests, size matters. On Earth, NASA uses 5 cm by 25 cm samples of flammable material. But pieces that big aren’t allowed on the station (with some exceptions when there is no practical alternative, such as the crew’s clothing). So experiments like BASS-M (which follows up on earlier BASS combustion experiments carried out on the station from 2011 to 2013) make do with small samples, about one centimeter by three centimeters.

“The problem with small samples is that a lot of aspects of the fire don’t scale linearly, so you can’t look at a tiny, one-centimeter fire and extrapolate that to one that’s a foot wide or something,” said David Urban, a combustion researcher at NASA’s Glenn Research Center.

Scientists would like to know exactly how large-scale fires would grow and spread in microgravity, but it’s too dangerous to conduct that kind of experiment on a spacecraft with astronauts on board. Instead, safety engineers have to rely mostly on models based on how flames spread in Earth’s gravity, and on a few small combustion experiments in space.

Sometimes you just need a bigger fire. So Urban and co-investigator Gary Ruff designed the Spacecraft Fire Experiment (Saffire), a series of six tests that will ignite and study contained fires aboard returning Cygnus cargo ships (the next of which is scheduled to depart the station on Friday). When they leave the ISS, the Cygnus ships contain only trash, and they burn up during re-entry. They’re expendable, which makes them the perfect place to set a fire.

When the next Cygnus (number OA-6) launches on March 20, it will carry, along with new supplies for the station,  the experimental hardware for Saffire-I. A metal box with fans at either end houses a 0.4- by 0.94-meter sheet of SIBAL cloth, a blend of 75 percent cotton and 25 percent fiberglass. Cotton is used in crew clothing, towels, and other cloth items aboard the station, and the fiberglass blend keeps the sample material from ripping and tearing as it burns. The fans will regulate airflow into and out of the fire.

After Cygnus detaches from the station in mid-May, a ground team will turn on power to the Saffire hardware and activate an electronic igniter at one corner of the SIBAL fabric. As the sample burns, instruments will measure temperature, pressure, and concentrations of oxygen and carbon dioxide near the fire. Video cameras will record the shape, growth, and spread of the flames.

A Cygnus cargo vehicle on its way up to the space station last December. This one comes home on Friday.

A Cygnus cargo vehicle on its way up to the space station last December. This one comes home on Friday. (NASA)

The fire should consume the sample fabric and burn itself out in about two hours, but Cygnus will spend another four days in orbit, downlinking to stations on Earth so the researchers can retrieve Saffire’s experimental data before the resupply ship re-enters Earth’s atmosphere and breaks up over the Pacific.

Saffire-II is scheduled to launch on OA-7 in October. With nine smaller samples—including more SIBAL cloth, Nomex, and plexiglass—it will replicate the flammability tests that NASA conducts on Earth. That should help researchers determine how well those tests predict the materials’ flammability in microgravity.

In 2017, Saffire-III will repeat Saffire-I’s large-scale fire, but this time with a stronger airflow. Since airflow is the main factor that influences the size of flames in space, researchers expect to see larger flames in Saffire-III.

The recent BASS-M experiments have helped lay the groundwork for these first three fire experiments, just as they will prepare the way for Saffire-IV through Saffire-VI. These later missions will study how heat and pressure from large fires could affect the rest of the spacecraft cabin, and will give NASA a chance to demonstrate fire suppression technologies that it has spent the last several years developing.

 


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Russia’s Big Plan To Finally Put Cosmonauts on the Moon

​Making sense of the latest shakeup at Roscosmos.​

NASA’s wild new plan to hunt for life on Mars would test SpaceX in ways never done before

Jessica Orwig

spacexSpaceX Photos on Flickr

There are 99 Mars rocks on Earth, but they’re not the kind that scientists need in order to resolve the all-too-intriguing  mystery of whether there is — or once was — life on Mars.

So far, all efforts to answer this question have painted a picture of an ancient Mars once covered in water with a thicker atmosphere and warmer temperatures — a world similar to Earth. But no signs of past or present life have been found, yet.

That’s why a team of scientists at NASA’s Ames Research Center in California have come up with a wild notion to do what has never been done before: transport rocks currently on Mars to Earth.

NASA has been seriously considering a sample-return mission like this for a while, ranking it as the highest-priority big-budget mission for the future in the U.S. National Research Center’s 2013 decadal survey. The return mission that NASA envisioned in 2013 would cost $6 billion, but the team at NASA’s Ames Research Center thinks they might have found a cheaper way.

Enter the “Red Dragon” mission, which would see NASA team up with Elon Musk’s company SpaceX, once again, for an epic mission of engineering firsts, including the first time anyone will have launched a vehicle off the surface of Mars.

spaceXSpaceX Photos

The project would launch a modified version of SpaceX’s current Dragon spacecraft to the Red Planet by as early as 2022, hence the project name “Red Dragon.”

The project is “technically feasible with the use of these emerging commercial technologies, coupled with technologies that already exist,” NASA senior systems aerospace engineer Andy Gonzales told NBC News.

Why we need to get Mars rocks back to Earth

Right now, the only Mars rocks available to scientist are not really rocks at all. They’re meteorites that were flung into space by a powerful impact and later plummeted to Earth at blazing speeds of more than 160,000 miles per hour.

However, this sort of rough, bumpy ride might have destroyed any valuable evidence within the rocks that could point to past life on Mars. And while NASA’s Curiosity rover is currently drilling into the Martian surface in search for signs of ancient alien life, it has come up empty-handed.

To determine, once and for all, whether Mars once harbored a thriving ecosystem on its watery and warm former self, scientists need to get their hands on Martian rocks that are sitting on the surface right now.

mars waterESO/M. KornmesserIllustration of what Mars might have looked like covered in water billions of years ago.

“Red Dragon” would follow NASA’s Mars 2020 mission, scheduled to launch a rover similar to Curiosity to Mars in 2020 — if the project is fully funded.

The Dragon spacecraft would then retrieve the samples taken by the Mars 2020 rover, store them in a Mars Ascent Vehicle (MAV), which would then launch the samples back to Earth, as described in the graphic below:

red dragon mission conceptNASA Ames Research Center/Red Dragon Internal Study Team

Gonzales and his team have not approached SpaceX yet to see if Elon Musk and his company would actually be interested in such a mission. First, the team needs to get NASA to approve the concept and fund the mission, which was first proposed last year.

Despite no funding in site, Gonzales is still actively pushing for the project, which he discussed last week during a NASA Future In-Space Operations working group. Gonzales told NBC News that his team has not estimated the total cost of “Red Dragon” but they suspect it will cost less than NASA’s $6 billion mission envisioned in the U.S. National Research Center’s 2013 decadal survey.

Spacecraft built from graphene could fly without any fuel

 

Graphene is a wonder material made of carbon atoms arranged in a honeycomb lattice. (Photo: Wiki Commons)

Even though it is only one atom thick, graphene is 200 times stronger than steel. It conducts heat and electricity with great efficiency, is nearly transparent, and might just be the most useful material ever discovered. The amazing properties of graphene, as well as the many inventions that have spawned from its discovery, are becoming too numerous to count. Now scientists have stumbled upon yet another incredible hallmark of this wonder material: It turns light into motion, reports New Scientist.
This latest graphene breakthrough came entirely by accident. Researchers discovered it while using a laser to cut a sponge made of crumpled sheets of graphene oxide. As the laser cut into the material, it mysteriously propelled forward. Although lasers have been shown to shove single molecules around, they shouldn’t be physically capable of moving a structure as large as the graphene sponge.
Baffled, researchers investigated further. The graphene material was put in a vacuum and again shot with a laser. Incredibly, the laser still pushed the sponge forward, and by as much as 40 centimeters. Researchers even got the graphene to move by focusing ordinary sunlight on it with a lens.
How is this possible? Researchers still aren’t sure, but there are two leading theories. One explanation is that the material is acting like a solar sail. Basically, photons can transfer momentum to an object and propel it forward, and in the vacuum of space this effect can accumulate and even generate enough thrust to move a spacecraft.
When researchers tested the solar sail theory, however, it worked too well. This led them to consider a second possibility, that the graphene is absorbing the laser’s energy, building up a charge of electrons. Eventually extra electrons are released, which act like a propellant, pushing the graphene material in the opposite direction.
Though this second theory is a bit vague and incomplete, scientists were able to detect a current flowing away from the graphene as it was exposed to a laser, suggesting that the theory is at least on the right track.
So what does this all mean? It means that researchers may have just accidentally discovered a propulsion system for a spacecraft that requires no fuel whatsoever. Essentially, a spacecraft built from graphene could explore the heavens powered by nothing more than sunlight.
“While the propulsion force is still smaller than conventional chemical rockets, it is already several orders larger than that from light pressure,” wrote researcher Yongsheng Chen and colleagues of the discovery.
More study is required before researchers can say for sure if the material can offer a viable alternative to fuel propulsion, but the results so far are exciting. Truly, there seems to be no end to the amazing qualities of graphene.

By: Bryan Nelson