Time Space Science

Alien creatures are the least of NASA's worries when it comes to moon travel. There are several potential threats to future missions - with space radiation at the top of the list. Now, a group of students at North Carolina State University has developed a "blanket" of sorts that covers lunar outposts - the astronauts' living quarters - to provide astronauts protection against radiation while also generating and storing power.
Astronauts who previously traveled to the moon had little protection against radiation, but were only exposed to it for a short amount of time. NASA's plans to return astronauts to the moon by 2020 - and to potentially keep them there for several months at a time - could be stymied by space radiation.

The surface of the moon is exposed to cosmic rays and solar flares - making radiation hard to stop with shielding. When these rays hit matter, they produce a dangerous spray of secondary particles which, when penetrating human flesh, can damage DNA, boosting the risk of cancer and other maladies.

Groups all over the globe are trying to determine ways to combat space radiation - including Michael Sieber, Ryan Boyle and Anne Tomasevich, all recent graduates of the textile engineering program at NC State. Their design of a lunar radiation shield with the ability to protect its inhabitants from radiation was reviewed by a panel of industry experts and chosen as one of 10 undergraduate abstract finalists in the Revolutionary Aerospace Systems Concepts Academic Linkage (RASC-AL) competition.

Sponsored by NASA and the National Institute of Aerospace, the RASC-AL competition challenges university students to think about what sorts of conditions astronauts will face when returning to the moon, then design projects that might become part of actual lunar exploration.

"We had many factors to consider in developing this outpost cover - not just being able to protect against radiation," Sieber says. "The product needed to be as lightweight as possible to feasibly fit on the transportation module, and have the ability to be easily erected by a minimum number of astronauts for immediate use once landing on the moon."

"These obstacles are where our knowledge of textile properties will give us an advantage," adds Dr. Warren Jasper, professor of textile engineering and advisor for the project. "This is a competition aimed at aerospace engineering students, but we understand the properties associated with different textile materials, and that gives us unique insight on how to troubleshoot some of these issues."

The "lunar texshield" is made from a lightweight polymer material that has a layer of radiation shielding that deflects or absorbs the radiation so astronauts are only exposed to a safe amount. The outermost surface of the shield includes a layer of solar cells to generate electricity, backed up by layers of radiation-absorbing materials. The advantages of the materials used in the design include flexibility, large surface area, ease of transportation, ease of construction and the ability to have multiple layers of independent functional fabrics.

The students will present their lunar texshield at the 2009 RASC-AL Forum held June 1-3 in Cocoa Beach, Fla. The project will be judged by a steering committee made up of experts from NASA, industry and universities.

"We aren't even sure what the prize is for being named first place - but that wasn't what was important to us," Sieber says. "We used what we've learned throughout our college careers and were able to apply that logic to provide a solution a real-world problem. That is what is cool to us."


http://www.ncsu.edu/

An international team of astronomers have accurately determined the radius and mass of the smallest core-burning star known until now.
The observations were performed in March 2004 with the FLAMES multi-fibre spectrograph on the 8.2-m VLT Kueyen telescope at the ESO Paranal Observatory (Chile). They are part of a large programme aimed at measuring accurate radial velocities for sixty stars for which a temporary brightness "dip" has been detected during the OGLE survey.

The astronomers find that the dip seen in the light curve of the star known as OGLE-TR-122 is caused by a very small stellar companion, eclipsing this solar-like star once every 7.3 days.

This companion is 96 times heavier than planet Jupiter but only 16% larger. It is the first time that direct observations demonstrate that stars less massive than 1/10th of the solar mass are of nearly the same size as giant planets. This fact will obviously have to be taken into account during the current search for transiting exoplanets.

In addition, the observations with the Very Large Telescope have led to the discovery of seven new eclipsing binaries, that harbour stars with masses below one-third the mass of the Sun, a real bonanza for the astronomers

http://www.eso.org/public/

An international team, led by astronomers at the University of Hertfordshire in the UK, have discovered one of the coolest sub-stellar bodies ever found outside our own solar system, orbiting the red dwarf star Wolf 940, some 40 light years from Earth. Dr Ben Burningham of the University of Hertfordshire will present this discovery on Monday 20th April at the European Week of Astronomy and Space Science conference.
"Although it has a temperature of 300 degrees Celsius, almost hot enough to melt lead, temperature is relative when you study this sort of thing, and this object is cool by stellar standards. In fact this is the first time we've been able to study an object as cool as this in such detail", says Dr Burningham, "the fact that it is orbiting a star makes it extra special".

The object is thought to have formed like a star, but has ended up looking more like Jupiter. It is roughly the same size, despite being between 20 and 30 times as heavy, and when the infrared spectral "fingerprints" of the two objects are compared, their resemblance is striking.

The new object orbits its star at about 440 times the distance at which the Earth orbits the sun. At such a wide distance, it takes about 18,000 years to complete a single orbit.

Too small to be stars, so-called "brown dwarfs" have masses lower than stars but larger than gas giant planets like Jupiter. Due to their low temperature these objects are very faint in visible light, and are detected by their glow at infrared wavelengths.

Modelling the atmospheres of cool brown dwarfs is a complex task, but it is key to understanding what we see when we look at planets that orbit other stars. Models of emitted light from such objects, which are dominated by absorption due to water and methane gas, are sensitive to assumptions about their age and chemical make-up.

In most cases astronomers don't initially know much about the age and composition of brown dwarfs and this can make it hard to tell where the models are right, and where they are going wrong.

"What's so exciting in this case, is that we can use what we know about the primary star to find out about the properties of the brown dwarf, and that makes it an extremely useful find", explains Dr Burningham, "you can think of it as a Rosetta Stone for decrypting what the light from such cool objects is telling us".

The object has been named Wolf 940B, after the red dwarf star that it orbits, which was first catalogued by the pioneering German astronomer Max Wolf ninety years ago.

"Red dwarfs are the most populous stars in the Galaxy, and systems like this may be more common than we know" says Dr David Pinfield of the University of Hertfordshire, "As the generation of ongoing large scale surveys continues, we may discover a pack of Wolf-940B-like objects in our solar back yard."

Wolf 940B was initially discovered as part of a major infrared sky survey - the UKIRT Infrared Deep Sky Survey (UKIDSS) which is being carried out using the United Kingdom Infrared Telescope (UKIRT) on Mauna Kea in Hawaii.

The object was found as part of a wider effort to find the coolest and least luminous bodies in our local Galactic neighbourhood, but it was then found to be a companion to the nearby red dwarf Wolf 940 through its common motion across the sky. The data used to confirm the discovery were obtained using telescopes in Chile, the Canary Islands and Hawaii.

Its temperature was then confirmed using data from the Gemini-North telescope on Mauna Kea. The team's findings will soon be published in the Monthly Notices of the Royal Astronomical Society.

Following its discovery with ground based telescopes, Wolf 940B, has since been observed by the NASA's Spitzer Space Telescope, and the findings from those observations will be published later this year.

"This object is going to continue to provide insights into the processes of cool brown dwarf, and warm planetary atmospheres for some time to come", says Dr Sandy Leggett, of the Gemini Observatory, "finding it was just the first step".


http://www.ras.org.uk/

Boring” light from red dwarf star Gliese 581 means better odds for extraterrestrial life in that planetary system, according to University of British Columbia astronomer Jaymie Matthews.

Approximately 20.5 light years from the Earth, Gliese 581 made the headlines in April 2007 when European scientists discovered a planet, named Gliese 581c. Dubbed “SuperEarth,” the planet orbits Gliese 581 and could have water -- and thus able to support life.

“The Gliese 581 system is the first to be found -- beyond our own Earth -- that might have a liveable planet,” said Matthews.

Using Canada Space Agency’s suitcase-sized space telescope, the Microvariability and Oscillations of STars (MOST), Matthews put Gliese 581 on a six-week scientific stakeout following the April discovery. He will present his findings today at the Canadian Astronomical Society’s annual meeting in Kingston, Ontario.

Matthews and his team searched for the subtle dips in the light from the star when the planet’s orbit carried it directly between the star and the Earth, resulting in a “mini-eclipse” every 13 days. The depth of the dips would help researchers determine the size of the planet Gliese 581c, while the behaviour of the starlight at other times would help astronomers gauge the suitability of Gliese 581 as a “home star,” a star able to sustain life on planets around it.

“Gliese 581 seems remarkably stable over the six weeks it was monitored by MOST,” said Matthews. “The brightness of the star changed by only a few tenths of a percent over that time. This level of stability means that it provides a stable source of light -- hence heat -- to the surface of planet Gliese 581c.

“The climate there should not be a wild rollercoaster ride that would make it difficult for life to get a foothold,” said Matthews. “It also suggests the star is quite old, and settled in its ways, and that the planets around it have probably been around for billions of years.”

It took approximately 3.5 billion years for life on Earth to reach the level of complexity that we call human, said Matthews. “So if Gliese 581 has been around for at least that long, it’s more encouraging for the prospects of complex life on any planet around it.”

With space missions like MOST, the French satellite COROT, which joined MOST in orbit late last December, and the American Kepler mission due for launch in November 2008, Matthews predicts that other ‘Earthy’ worlds will come to light in the coming months and years.

“Some of them will have orbits that produce planetary alignments,” said Matthews. “Not the kind that excites somebody reading a horoscope but the kind that’s exciting for astronomers because they will allow us to test our models of alien worlds -- worlds that might be homes to neighbours in our Galactic city, the Milky Way.”

MOST is a Canadian Space Agency mission, jointly operated by Dynacon Inc., the University of Toronto Institute for Aerospace Studies and the University of British Columbia, with the assistance of the University of Vienna.

http://www.astro.ubc.ca/MOST/