Posted on by Amy Shira Teitel

NASA’s Going Green

he launch of the Phoenix spacecraft on a Delta II rocket in 2007. NASA is looking for alternatives to hydrazine monopropellant, used en route by Phoenix's navigational thrusters Image credit: NASA/Sandra Joseph and John Kechele

[/caption]

NASA announced yesterday that it’s looking for new technology proposals using environmentally friendly fuels to launch payload. The space agency is hoping to move away from hydrazine, the fuel that currently launches anything that travels beyond the atmosphere from commercial satellites to private spaceflight and exploration probes. 

As a rocket propellant, hydrazine is great. It’s incredibly efficient, can be stored for long periods of time, has excellent handling characteristics, is stable up to 250 degrees Celsius (482 Fahrenheit) under normal conditions, and decomposes cleanly.

It also happens to be extremely toxic.

Shifting away from hydrazine would be a shift away from known environmental hazards and pollutants. There would be fewer operational hazards for those dealing with fueled rockets before launch. The change could also simplify the complexity of the rockets’ systems and, possibly, increase overall propellant performance.

The ALICE powered rocket before launch. Image credit: Dr. Steven F. Son, Purdue University

The benefits don’t stop there. Advantages on every level trickle down. “High performance green propulsion has the potential to significantly change how we travel in space,” said Michael Gazarik, director of NASA’s Space Technology Program at the agency’s headquarters in Washington. “By reducing the hazards of handling fuel, we can reduce ground processing time and lower costs for rocket launches, allowing a greater community of researchers and technologists access to the high frontier.”

Developing green propellants won’t be quick or easy. It will be a major challenge for NASA, particularly from a cost, schedule, and risk perspective. The agency has established the Technology Demonstration Missions Program at the Marshall Spaceflight Centre in Huntsville, Alabama to oversee the green fuel program. It will act as a bridge between laboratory confirmation of a technology and its use on a mission.

This isn’t the first time NASA has tried to develop green fuel. In 2009, the space agency and the US Air Force successfully launched a 9-foot rocket 1,300 vertical feet using a mixture of aluminum powder and water ice. The mixture, called ALICE, has been studied since the 1960s as an alternative propellant. The reaction between substances produces a large amount of energy during combustion and green exhaust products.

Environmental impact aside, fuels like ALICE could be manufactured on the Moon or Mars, negating the cost of sending propellants along as cargo on long-duration missions. This would be when designing long-term missions.

The winning aircraft - Pipistrel-USA, Taurus G4 - during its flight as part of the miles per gallon flight. (NASA/Bill Ingalls)

Aviation, too has been an outlet for NASA’s green fuel initiatives in the past. 2011’s CAFE Green Flight Challenge, sponsored by Google, had competitors in general aviation design aircraft capable of flying 200 miles in less than two hours and use less than one gallon of fuel per passenger. The first place winner of $1.35 million was the team Pipistrel-USA.com of State College, Pennsylvania used an electric aircraft that achieved twice the fuel efficiency required by the competition — they flew 200 miles on the equivalent of a half-gallon of fuel per passenger.

With this shift to green fuels, NASA hopes to partner with American companies to usher in a new environmentally friendly era of open access to space. The agency is planing to make multiple contract awards for green technologies with no single away exceeding $50 million.

Source: NASA

 

Posted on by Nancy Atkinson

Phil Plait’s Five Guides to the Universe

All writers love to read, and our friend Phil Plait, the Bad Astronomer is no exception. And since we often get asked what space and astronomy books we’d recommend, let us point you in the direction of a new interview with Phil where he shares five of his favorite books about the Universe. It’s on a website called “The Browser” which has a series of interviews called Five Books, where they ask various experts what five books on a subject they recommend. It’s a great interview, and I’d recommend going to The Browser website anyway, just to see their banner. Their mascot looks like a tardigrade, the tiny aquatic invertebrates that have been sent into space.

Posted on by Paul Scott Anderson

Tidal Heating on Some Exoplanets May Leave Them Waterless

Venus as photographed by the Pioneer spacecraft in 1978. Some exoplanets may suffer the same fate as this scorched world. Credit: NASA/JPL/Caltech

[/caption]

As the number of exoplanets being discovered continues to increase dramatically, a growing number are now being found which orbit within their stars’ habitable zones. For smaller, rocky worlds, this makes it more likely that some of them could harbour life of some kind, as this is the region where temperatures (albeit depending on other factors as well) can allow liquid water to exist on their surfaces. But there is another factor which may prevent some of them from being habitable after all – tidal heating, caused by the gravitational pull of one star, planet or moon on another; this effect which creates tides on Earth’s oceans can also create heat inside a planet or moon.

The findings were presented at the January 11 annual meeting of the American Astronomical Society in Austin, Texas.

The habitability factor is determined primarily by the amount of heat coming from the planet’s star. The closer a planet is to its star, the hotter it will be, and the farther out it is, the cooler it will be. Simple enough, but tidal heating adds a new wrinkle to the equation. According to Rory Barnes, a planetary scientist and astrobiologist at the University of Washington, “This has fundamentally changed the concept of a habitable zone. We figured out you can actually limit a planet’s habitability with an energy source other than starlight.”

This effect could cause planets to become “tidal Venuses.” In these cases, the planets orbit smaller, dimmer stars, where in order to be in that star’s habitable zone, they would need to orbit much closer in to the star than Earth does with the Sun. The planets would then be subjected to greater tidal heating from the star, enough perhaps to cause them to lose all of their water, similar to what is thought to have happened with Venus in our own solar system (ie. a runaway greenhouse effect). So even though they are within the habitable zone, they would lack oceans or lakes.

What’s problematic is that these planets could subsequently actually have their orbits altered by the tidal heating so that they are no longer affected by it. They would then be more difficult to distinguish from other planets in those solar systems which may still be habitable. While technically still within the habitable zone, they would have effectively been sterilized by the tidal heating process.

Planetary scientist Norman Sleep at Stanford University adds: “We’ll have to be careful when assessing objects that are very near dim stars, where the tides are much stronger than we feel on present-day Earth. Even Venus now is not substantially heated by tides, and neither is Mercury.”

In some cases, tidal heating can be a good thing though. The tidal forces exerted by Jupiter on its moon Europa, for example, are thought to create enough heat to allow a liquid water ocean to exist beneath its outer ice crust. The same may be true for Saturn’s moon Enceladus. This makes these moons still potentially habitable even though they are far outside of the habitable zone around the Sun.

By design, the first exoplanets being found by Kepler are those that orbit closer in to their stars as they are easier to detect. This includes smaller, dimmer stars as well as ones more like our own Sun. The new findings, however, mean that more work will need to be done to determine which ones really are life-friendly and which ones are not, at least for “life-as-we-know-it” anyway.

Posted on by Nancy Atkinson

Freaky Dancing Plasma on the Sun

Normally plasma from the Sun either shoots off into space or loops back on the Sun’s surface. But the Solar Dynamics Observatory captured some plasma that couldn’t make up its mind. Here, darker, cooler plasma slid and shifted back and forth above the Sun’s surface for 30 hours on February 7-8, 2012. The view is shown in extreme ultraviolet light. As a backdrop, an active region just rotating into view shows bright plasma gyrating into streams — normally how the plasma behaves. SDO scientists say the darker particles are being pulled back and forth by competing magnetic forces, tracking along strands of magnetic field lines.

And by the way, tomorrow is SDO’s 2nd anniversary! It launched two years ago on February 11, 2010. Happy anniversary, SDO and thanks for all the great videos and data so far! We wish you many more!

Posted on by Nancy Atkinson

Is Venus’ Rotation Slowing Down?

Venus Express in orbit since 2006 around our nearest planetary neighbor. Credits: ESA

New measurements from ESA’s Venus Express spacecraft shows that Venus’ rotation rate is about 6.5 minutes slower than previous measurements taken 16 years ago by the Magellan spacecraft. Using infrared instruments to peer through the planet’s dense atmosphere, Venus Express found surface features weren’t where the scientists expected them to be.

“When the two maps did not align, I first thought there was a mistake in my calculations as Magellan measured the value very accurately, but we have checked every possible error we could think of,” said Nils Müller, a planetary scientist at the DLR German Aerospace Centre, lead author of a research paper investigating the rotation.

[/caption]

Using the VIRTIS infrared instrument, scientists discovered that some surface features were displaced by up to 20 km from where they should be given the accepted rotation rate as measured by the Magellan orbiter in the early 1990s.

Over its four-year mission, Magellan determined the length of the day on Venus as being equal to 243.0185 Earth days. But the data from Venus Express indicate the length of the Venus day is on average 6.5 minutes longer.

What could cause the planet to slow down? One possibility may be the raging weather on Venus. Recent atmospheric models have shown that the planet could have weather cycles stretching over decades, which could lead to equally long-term changes in the rotation period. The most important of those forces is due to the dense atmosphere – more than 90 times the pressure of Earth’s and high-speed weather systems, which are believed to change the planet’s rotation rate through friction with the surface.

Earth experiences a similar effect, where it is largely caused by wind and tides. The length of an Earth day can change by roughly a millisecond and depends seasonally with wind patterns and temperatures over the course of a year.

But a change of 6.5 minutes over a little more than a decade is a huge variation.

Other effects could also be at work, including exchanges of angular momentum between Venus and the Earth when the two planets are relatively close to each other. But the scientists are still working to figure out the reason for the slow down.

These detailed measurements from orbit are also helping scientists determine whether Venus has a solid or liquid core, which will help our understanding how the planet formed and evolved. If Venus has a solid core, its mass must be more concentrated towards the center. In this case, the planet’s rotation would react less to external forces.

“An accurate value for Venus’ rotation rate will help in planning future missions, because precise information will be needed to select potential landing sites,” said Håkan Svedhem, ESA’s Venus Express project scientist.

Venus Express will keep monitoring the planet to determine if the rate of rotation continues to change.

Source: ESA

Posted on by Jason Major

Sandy Streets Over the Atlantic

Dust from the Sahara blows past the Cape Verde islands on Feb. 9, 2012 (Chelys)

[/caption]

Thick dust from the Sahara blowing over the ocean off the western coast of Africa encounters the islands of Cape Verde, forming a wake of swirling “vortex streets” visible by satellite.


These swirls are also known as von Karman vortices. When wind encounters the island, the disturbance in the flow propagates downwind in the form of a double row of vortices, which alternate their direction of rotation.

Such effects can be seen anywhere a liquid fluid — including air — flows around a solid body. They are named after engineer and fluid dynamicist Theodore von Kármán.

In the image above, the dust and sand is thick enough to nearly block out some of the islands entirely. See the full scale version here on the Chelys “EOSnap” Earth Snapshot site.

Image via EOSnap/Chelys SRRS (Satellite Rapid Response System).

Posted on by Nancy Atkinson

Watch Live Webcast from the Keck Observatory

On Thursday, Feb. 9, 2012, Keck Observatory will be hosting a live webcast of an astronomy talk by Dr. Tom Soifer of Caltech, who is the Director of the Spitzer Science Center. The title of the talk is “Seeing the Invisible Universe,” and Soifer will discuss the latest exciting results from NASA’s Spitzer Space Telescope. The webcast begins at 7 pm Hawaiian Time, 9 pm Pacific Time (5 am GMT, Feb 10) and will be streamed from the Kahilu Theatre in Waimea-Kamuela, on the Big Island of Hawaii. Watch in the window above (click the play button) or watch on the Keck website.

Posted on by Jason Major

The Moon Trees of Apollo 14

Apollo 14's splashdown in the Pacific on Feb. 9, 1971. (NASA/Ed Hengeveld)

On this day in 1971 Apollo 14 astronauts Alan Shepard, Jr., Stuart Roosa and Edgar Mitchell returned to Earth, splashing down in the Pacific Ocean at 21:05 UT (4:05 p.m. EST). They were recovered by the USS New Orleans, and returned to the U.S. by way of American Samoa. But the three men weren’t the only living creatures to come back from the Moon on Feb. 9, 1971… in fact, human astronauts were in the minority that day.

Al, Stu and Ed shared their lunar voyage with nearly 500 trees.

As Shepard and Mitchell gathered samples near their landing site in a region named Fra Mauro, Apollo 14 pilot and ex-smoke jumper Stuart Roosa orbited above in “Kitty Hawk”, the mission’s Command Module. It may sound like a lonely job, but he was far from alone. Within his personal kit were small containers containing 400-500 seeds, part of a joint NASA/USFS project to examine the effects, if any, of space travel on such organisms.

The seeds were selected from a variety of tree species: redwood, loblolly pine, sycamore, Douglas fir, and sweetgum seeds were all chosen to accompany Roosa on his 34 orbits around the Moon.

A control group of the same seed varieties were kept on Earth for comparison.

Stuart Roosa had worked for the Forest Service in the 1950s before becoming an Air Force test pilot and then eventually an Apollo astronaut. Being charged with the care of the seeds was a particularly symbolic assignment for Roosa, who had once fought wildfires as a smoke jumper.

Even though there was a mishap during the decontamination process after return to Earth, wherein some containers burst open and seeds were inadvertently mixed together, many of the seeds successfully germinated at Forest Service stations in Mississippi and California. The seedlings were eventually sent to locations around the country and around the world to commemorate the success of the Apollo program.

There was even a second generation, called half-moon trees.

A Moon Tree located outside Goddard Space Flight Center. (GSFC)

Many of these “Moon Trees” and their descendants still stand today. In some instances they are marked with a plaque or a sign… in others, no special marking denotes their significance. Those unmarked trees stand as silent reminders of an earlier and perhaps even bolder era of human space flight.

Me, Heather Archuletta, and Greg ___ in front of a 2nd-generation Moon Tree outside the Holliston Police Department in Massachusetts. (© Jason Major)
Me, Heather Archuletta, and Greg Riley in front of a 2nd-generation Moon Tree outside the Holliston Police Department in Massachusetts, Oct. 2013. (© Jason Major)

Read more about the Moon Trees on this page by David Williams of NASA’s Goddard Space Flight Center. And if you know of a Moon Tree that is not on Mr. William’s list, please contact him to have it included. Williams has endeavored to locate the whereabouts and status of these trees since 1996, as there had been no systematic records previously kept of them.

“I think when people are aware of the heritage of the trees, they usually take steps to preserve them,” said Williams in recollection of one tree that was nearly knocked down during a building renovation. “But sometimes people aren’t aware. That’s why we want to locate as many as we can soon. We want to have a record that these trees are — or were — a part of these communities, before they’re gone.”

Posted on by Nancy Atkinson

Join UT’s First Live Interview with Rover Driver Scott Maxwell

Rover Driver Scott Maxwell with a model of MER. Photo courtesy Scott Maxwell

[/caption]

How often have you wanted to be a fly on the wall during media interviews of top scientists and engineers? Here’s your chance! On Friday, February 10, we’ll be having our first live interview via a Google+ Hangout On Air. We’ve done the weekly Space Hangout for several weeks now and Fraser has done multiple virtual star parties via a Hangout On Air. Now we’ll start the first of what we hope are many live interviews that we’ll share with our readers and fans. We’re excited that Mars rover driver Scott Maxwell, will be joining us, and he will provide insight on the plans for the Opportunity rover’s upcoming winter, a look back at the 8 years and counting for the rovers, a look ahead to the future, and more.

The Hangout On Air will start at 18:00 UTC (1 pm EST,12 noon CST, 10 am PST) or you can check here at the fancy-schmancy time and date announcement Scott put together that shows the time in almost every time zone possible.

How do you find the Hangout? The best way is to join Google+ and “circle” Fraser and the Hangout On Air will show up in his timeline. You can also circle Nancy, who will also provide a link, but within Fraser’s timeline there will also be the opportunity for you to post questions that we can ask Scott during the live interview.

If you can’t watch live, the Hangout will be recorded and we’ll post it later on Friday on Universe Today.

We hope you’ll join us!

Posted on by Paul Scott Anderson

New Computer Simulations Show Earth’s Spaghetti-Like Magnetosphere

Supercomputer simulation showing the tangled magnetosphere surrounding Earth. Credit: OLCF

[/caption]

A new computer simulation is showing Earth’s magnetosphere in amazing detail – and it looks a lot like a huge pile of tangled spaghetti (with the Earth as a meatball). Or perhaps a cosmic version of modern art.

The magnetosphere is formed by the Sun’s magnetic field interacting with Earth’s own magnetic field. When charged particles from a solar storm, also known as a coronal mass ejection (CME), impact our magnetic field, the results can be spectacular, from powerful electrical currents in the atmosphere to beautiful aurorae at high altitudes. Space physicists are using the new simulations to better understand the nature of our magnetosphere and what happens when it becomes extremely tangled.

Using a Cray XT5 Jaguar supercomputer, the physicists can better predict the effects of space weather, such as solar storms, before they actually hit our planet. According to Homa Karimabadi, a space physicist at the University of California-San Diego (UCSD), “When a storm goes off on the sun, we can’t really predict the extent of damage that it will cause here on Earth. It is critical that we develop this predictive capability.” He adds: “With petascale computing we can now perform 3D global particle simulations of the magnetosphere that treat the ions as particles, but the electrons are kept as a fluid. It is now possible to address these problems at a resolution that was well out of reach until recently.”

It helps that the radiation from solar storms can take 1-5 days to reach Earth, providing some lead time to assess the impact and any potential damage.

The previous studies were done using the Cray XT5 system known as Kraken; with the new Cray XT5 Jaguar supercomputer, they can perform simulations three times as large. The earlier simulations contained a “resolution” of about 1 billion individual particles, while the new ones contain about 3.2 trillion, a major improvement.

So next time you are eating that big plate of spaghetti, look up – the universe has its own recipes as well.

The original press release from Oak Ridge National Laboratory is here.