December 31, 2012
NASA has big plans for manned travel in deep space. Although missions haven’t been officially announced yet, experts speculate that the agency plans to establish a space station on the far side of the moon sometime in the next decade, a stepping stone towards landing on an asteroid in 2025 and potentially trying to reach Mars sometime around 2033.
Getting to Mars, though, would require astronauts to endure a round-trip (or possibly one-way) journey that could be as long as three years—which could be particularly worrisome given the results of a study on the health effects of cosmic radiation published today in PLOS ONE. Although we’ve known for some time that the radiation experienced by space travelers could pose problems over the long term, this new study is the first to establish a link with an increased chance of Alzheimer’s disease and dementia.
The researchers, a group from NASA and the University of Rochester, came to the finding by testing a specific type of cosmic radiation—high-mass, high-charged (HZE) iron particles—on mice. This kind of radiation is of particular concern, because its high speed (a result of the force of the exploding stars it’s originally expelled from, light-years away) and large mass mean that it’s tricky to protect against.
Here on Earth, we’re largely protected from it and other types of radiation by our planet’s atmosphere and magnetic field, but even a short time in deep space means much higher levels of exposure, and we haven’t yet figured out how to construct a shield that effectively blocks it. ”Because iron particles pack a bigger wallop it is extremely difficult from an engineering perspective to effectively shield against them,” M. Kerry O’Banion, the paper’s senior author, said in a statement. “One would have to essentially wrap a spacecraft in a six-foot block of lead or concrete.”
After producing radioactive particles that generate this type of radiation using a particle accelerator at the Brookhaven National Laboratory on Long Island, the researchers exposed the mice to varying doses of the radiation, including levels comprable to what astronauts would experience on a mission to Mars. The breed of mice they used has been the subject of numerous studies on dementia and Alzheimer’s, so scientists have a relatively good understanding of how rapidly the disease and related symptoms develop over time.
But when the researchers put the mice through a series of behavioral tests—seeing if they were capable of remembering objects or specific locations—those that had been exposed to greater levels of radiation were far more likely to fail, demonstrating signs of neurological impairment far more early in life than is typical in the breed. Additionally, autopsies of these mice revealed that their brains contained higher levels of beta amyloid, the “plaque” considered a hallmark of Alzheimer’s disease.
This result doesn’t mean we have to abandon dreams of deep space travel—or even that this kind of radiation definitively leads to accelerated neurological degeneration—but it does show that cosmic radiation is going to be a graver concern the longer space missions get. Ingenious engineering has addressed many of the difficulties of space flight, but this remains a problem to be solved.
“These findings clearly suggest that exposure to radiation in space has the potential to accelerate the development of Alzheimer’s disease,” O’Banion said. “This is yet another factor that NASA, which is clearly concerned about the health risks to its astronauts, will need to take into account as it plans future missions.”
December 14, 2012
The year 2012 was a major one for science. We saw scientists develop a new type of drug to combat HIV, figure out how to store digital data in DNA—fitting an astonishing 700 terabytes of information into a single gram of it—and even invent a coating for the inside of condiment bottles that could eliminate our stuck-ketchup-headaches once and for all (though, admittedly, this one is a little less groundbreaking than the others). Yet a few milestones in particular—discoveries, technological feats, realizations, and inventions—stand out:
1. The Higgs Boson: The landmark discovery by the European Organisation for Nuclear Research (CERN) of the once-mythical particle might be the most significant scientific discovery of our lifetimes, but it’s also one of the most surprising. Stephen Hawking, the Einstein of our time, famously bet Michigan physicist Gordon Kane $100 that it would never be found.
In an interview with The Atlantic, physicist Lawrence Krauss explained why so many experts had agreed with Hawking, arguing that the existence of the Higgs—a particle (and associated field) that makes certain types of elementary particles behave as though they had mass—was just too convenient, as it was originally posited simply to explain away an apparent difficulty in an otherwise appealing theory in theoretical physics.
The theory seeks to unite all physical forces under the same set of rules. But how can electromagnetic forces–governed by massless photons–fit under the same theoretical umbrella as the weak force, which is governed by bosons with discernible mass that control radioactive decay? Efforts to answer this conundrum gave birth to the Higgs boson. Krauss noted,”It seemed too easy…It seemed to me that introducing an invisible field to explain stuff is more like religion than science…Great, I invented invisible hobgoblins to make things right.”
Incredibly, in this case, it turned out the hobgoblins were real.
2. Earth-Like Planets: 2012 featured a ton of exoplanet discoveries, but the sighting of HD 40307g was without a doubt the most unexpected and exciting. The planet, bigger than earth but not so large as to be a gas giant, seems to orbit in its sun’s “goldilocks zone” (not too hot and not too cold), making it potentially capable of hosting liquid water, considered a prerequisite for life as we know it.
Even better, it’s just 42 light-years away: distant by human standards, but fairly close by compared many of the astronomical objects, making future projects to observe the planet much more feasible.
3. Curiosity Reaches Mars: Okay, the mission itself wasn’t too surprising—it’s been in the works since 2004—but what was so astonishing was the sudden surge of public interest in the rover and in space exploration as a whole. For decades following the manned Apollo missions of the 1960s and 70s, general enthusiasm for space science had slowly ebbed. After Curiosity’s successful landing, though, it surged. Among other things, video of NASA engineers celebrating the feat went viral and the official Curiosity twitter account garnered some 1.2 million followers.
People are so interested in Curiosity‘s exploits, in fact, that even an engineer’s throwaway line about “a discovery for the history books” pumped up expectations so much that we were bound to be disappointed by the actual finding: that early Martian soil samples seem to be representative of what we know of the planet as a whole, and that its chemistry is complex enough to have potentially once supported life. Bigger news might come over the next few years, but as project scientist John Grotzinger said, “Curiosity’s middle name is patience.”
4. Climate Change Is Even Worse Than We Thought: After decades of warnings from scientists that our greenhouse gas emissions will soon wreak havoc with the climate, we’re now starting to see the consequences—and they sure aren’t pretty. As a whole, experts are saying that the even the most frightening climate scenarios have proved to be too conservative in their analysis of how rising carbon dioxide concentrations will alter precipitation patterns, drive ocean acidification, lead to more powerful storms and, in general, make most parts of the planet grow warmer.
One silver lining might be that the public is now starting to acknowledge climate change as a present-day problem, rather than a hypothetical trend that could take effect in the future. Sadly, this has come only after record-breaking heat waves, droughts and the tragic impacts of Hurricane Sandy. Although the most recent international climate talks in Doha accomplished little, there are hopes that this shift in opinion could lead to a long-awaited change in policy sometime soon.
5. A New Way to Desalinate Seawater: With world populations expected to keep growing and potable water projected to grow more scarce over the coming century, a practical and cheap means of desalinating sea water is one of materials science’s holy grails. In July, MIT researchers announced the development of a new method of desalinization using one-atom-thick sheets of graphene, a pure carbon substance. Their method could be far cheaper and less energy-intensive than existing systems—potentially providing a way to solve many of the world’s water problems once and for all.
August 14, 2012
Exoplanets—planets that orbit stars other than our own Sun—used to be the stuff of science fiction. Then, in 1992, astronomers spied one for the very first time. Now, at least 777 different exoplanets have been detected orbiting 623 different stars, and scientists project that as many as 160 billion exoplanets may exist in the Milky Way alone.
Researchers continue to detect these exoplanets at a rapid pace—since it launched in 2009, NASA’s Kepler space telescope has already help us find 74 confirmed planets and identify another 2,321 potential candidates—and we’ve discovered some truly fascinating ones so far. Here is a rundown of some of the most interesting and unusual:
1. GJ1214b, discovered last year, seemed like a typical exoplanet to astronomers at first glance. But when they tried to calculate the density of the supersized planet, with a diameter roughly 2.7 times that of Earth, they realized it was too light to be made up of rock—the planet had to be home to a remarkable amount of water. The “water” on this waterworld, just 40 light-years away, is not present in liquid form, but rather as steam or an exotic high-temperature ice that occurs only at extremely high pressures.
2. Kepler-16b is the closest thing we’ve found to Luke Skywalker’s home planet of Tatooine in Star Wars—it orbits not one star, but two. Discovered last year, the planet is relatively close to us, just 200 light-years away, and is a gas giant, similar to Saturn in both size and mass. Life on Kepler 16b, if it existed, would be truly strange: Every day would include two sunrises and two sunsets.
3. 2M1207b is cool for a surprisingly obvious reason: We can actually see it. While the vast majority of exoplanets are detected indirectly–by the slight dimming of their star, which we see when the planet crosses in front of it–this exoplanet is enormous and close enough that we can directly image it using infrared light. 2M1207b also has a fascinating creation story: Unlike the planets in our solar system, which formed out of a disc of material left over from the formation of the Sun, 2M1207b seems to have formed out of the gravitational collapse of a separate, giant nebula sometime in the distant past.
4. WASP-12b won’t be with us much longer. The hottest exoplanet ever discovered (at roughly 4,000 degrees Fahrenheit) orbits so closely to its star that it is literally being consumed by the heat and pull of gravity. Since the planet was discovered in 2008, scientists have detected that it is gradually being pulled into an oblong, football shape by its star; they now estimate that it has some 10 million years left to live. Additionally, the planet is the first one discovered that is home to significant quantities of carbon, the essential building block for life as we know it.
5. Kepler-20e and Kepler-20f are extremely intriguing for one particular reason: The pair of planets, part of the same star system, both appear to be roughly the same size as Earth. Although they are far too close to their star to be capable of supporting life (their average temperatures are 1,400 and 800 degrees Fahrenheit, respectively), the planets may have migrated inward over time, indicating that they could have been home to extraterrestrial life sometime long ago. Reaching the Kepler system by space shuttle would take about 36 million years—but if we somehow made the journey, there might be some rather interesting fossils to find.
August 9, 2012
Remotely controlling a rover on Mars can get a little bit complicated. Scientists and engineers must make thousands of decisions every day on what types of data to collect, what information to transmit back to Earth and where to guide the intrepid explorer next.
On top of all this, they must keep track of something most of us rarely consider: the time on Mars. Knowing exactly when afternoon arrives for a particular rover—either Opportunity, which landed in 2004 and is still in operation, or Curiosity, which arrived to great fanfare earlier this week—is crucial for its operators, since that is when data is uploaded from the craft and sent back to Earth.
“The rover downlink, in the afternoon on Mars, is what we use to plan the next day’s activities for the rover,” says Smithsonian scientist John Grant, who works on daily geologic data collection as well as long-term planning for the mission. “So we are tied to the time of the downlink and when the uplink of the commands will occur the next morning.”
The problem is that Mars has a 24-hour and 39-minute day, so its time zones don’t match up with any on Earth. Unlike, say, East Coast residents simply remembering to subtract three hours to know the time on the West Coast, scientists must keep track of a constantly varying difference between time zones. ”It’s confusing to keep track of two different times, especially when you are used to living on one time and working on another that keeps shifting,” Grant says.
Thankfully, there’s an app for that.
NASA has produced a free Java application called Mars24 that provides the exact times for a number of places on the Red Planet, including the current location of Opportunity (a.k.a. MER, the Mars Exploration Rover ), Curiosity (a.k.a. MSL, the Mars Science Laboratory) and even the immobile Viking 1 lander, which has been out of operation since 1982. You can also alter the settings to see the time at given Martian landmarks, such as Olympus Mons, the tallest mountain on any planet in the Solar System.
The app also includes a visual representation of Mars called a sunclock, which shows a map of which parts of the planet are currently light and dark.
Mars24 is available for Mac OS X, Windows and Linux. If you want to have a handy way to check the time on your smartphone, you’ll have to opt for a non-NASA app, such as Mars Clock or Mars Surface Times, both available in the App Store for iPhone, or Martian Time, available at Google Play for Android.
Of course, Mars24 is fun for members of the public interested in following Curiosity, but the pros have their own ways of keeping track of Martian time. Grant says that the software which shows his daily schedule of meetings and Mars-related events expresses each entry in both Earth and Mars times. Additionally, when working on the previous rovers Spirit and Opportunity, he and other members of the team wore special watches that actually ran on Martian time. (His watch is on view in the Air and Space Museum if you’d like to check the time for yourself.)
One technical aspect to note is that although a Martian day is actually longer than 24 hours, the convention is still to express the time there in terms of a 24 hour period for convenience. To do so, scientists simply divide the actual duration of a Martian day by 24 to calculate the length of a Martian hour, and divide that by 60 for the length of a Martian minute, and so on. So a Martian hour is slightly longer than an Earth hour, and a Martian minute slightly longer than an Earth minute. All in all, pretty otherworldly.
July 24, 2012
A spacecraft re-entering Earth’s atmosphere encounters temperatures as high as 1850 degrees Fahrenheit as it plummets downward at speeds approaching 7600 miles per hour. All this energy makes a robust shield to absorb the heat absolutely necessary to protect astronauts and equipment inside. But throughout NASA’s history, these heat shields—typically constructed out of rigid materials—have posed a safety issue, with brittle ceramic tiles responsible for the 2003 Columbia disaster.
Yesterday, NASA conducted a test of a novel approach to this problem: an inflatable fabric heat shield. Early yesterday morning, a rocket carrying a prototype launched 288 miles upward from NASA’s Wallops Flight Facility on Virginia’s Eastern Shore. After the experimental vehicle—known as the Inflatable Reentry Vehicle Experiment (IRVE-3)—was ejected from the rocket, the shield inflated according to plan and safely descended back to Earth over the course of about 20 minutes, landing in the Atlantic East of Cape Hatteras, North Carolina.
“Everything went like clockwork. The IRVE-3 performed just as it was supposed to,” said Neil Cheatwood, the principal investigator on the project. “It entered Earth’s atmosphere at Mach 10, ten times the speed of sound, and successfully survived the heat and forces of the journey.”
After three years in development, NASA’s research team created the innovative design, which is able to stand up to the stresses of space flight using lighter and more flexible materials. At launch, the shield is made up of a cone of uninflated rings of kevlar-woven fabric, all surrounded by a thermal blanket. During flight, the 680-pound heat shield separates from the launch rocket, and an inflation system pumps nitrogen into the unit until it forms a mushroom shape, with the upper cylinder roughly 10 feet in diameter.
“We like it when it looks simple,” said Carrie Rhoades, flight systems engineer. “It actually took quite a bit of work to get to where we are now. We have to do all kinds of different testing—in wind tunnels, high temperature facilities and laboratories.”
A previous experiment, IRVE-2, also successfully survived re-entry in August 2009, but with a much lighter payload and at much slower speeds. IRVE-3 experienced about 10 times as much heat, similar to what a heat shield would be expected to endure on an actual mission.
During the experimental flight, engineers closely monitored data from onboard cameras and thermometers to track whether the shield sufficiently protected from the craft from the immense amounts of heat generated. As they cheered the success, a high-speed U.S. Navy boat was dispatched to the splashdown area to retrieve the craft, so NASA personnel can study it for future missions.
NASA is conducting the tests to show that such inflatable designs could be used in the future to protect space capsules during planetary entry or descent and help return cargo to Earth from the International Space Station.” It’s great to see the initial results indicate we had a successful test of the hypersonic inflatable aerodynamic decelerator,” said James Reuther, deputy director of NASA’s Space Technology Program. “This demonstration flight goes a long way toward showing the value of these technologies to serve as atmospheric entry heat shields for future space.”
NASA plans to test increasingly-larger inflatable heat shields with other types of heat-resistant fabrics before eventually putting them to work on an actual mission. Next up is the High Energy Atmospheric Re-entry Test (HEART)—a concept design includes a larger heat shield, nearly 30 feet in diameter.
Using inflatable designs could allow for heat shields of significantly reduced sizes and weights—and consequently, spacecraft that can accommodate larger amounts of scientific equipment and life-sustaining supplies. NASA scientists predict the technology could be useful on future missions to anywhere with an atmosphere, including Mars, Venus, or even Titan, Saturn’s largest moon.