Month: January 2015

Solar sails are designed to capture the momentum from solar energy photons using large mirrored surfaces.

A tiny spacecraft designed to be pushed through space by ultra-thin “solar sails” will be launched in May by a U.S.-based non-profit group, 10 years after its first failed attempt.

The Planetary Society announced recently that its LightSail spacecraft will blast off on a test flight aboard an Atlas V rocket. The society is a non-profit space advocacy organization co-founded by the late astronomer Carl Sagan and headed by Bill Nye, best known as the Science Guy from his popular TV show.

According to CBC News, the LightSail spacecraft, a tiny cube satellite about the size of a loaf of bread, is expected to unfurl its four solar sails in June. The triangular sails are made of Mylar, about a quarter of the thickness of a garbage bag, and have a combined area of 32 square metres — equivalent to two parking spaces.

Solar sails are designed to capture the momentum from solar energy photons using large, mirrored surfaces. The small, continuous acceleration allows a spacecraft propelled by solar sails to reach high speeds over time.

“As LightSail breezes around the Earth, its shiny sails will be visible from the ground,” the Planetary Society says on its website for the project.

According to a blog post by Jason Davis, the society’s digital editor, the spacecraft won’t fly high enough to escape Earth’s atmospheric drag and demonstrate “true” solar sailing.

But it will gather time-lapse images of the sails’ deployment and engineering data that show how they perform in microgravity.

That, in turn, will be used to prepare for a second flight in 2016, at a higher altitude of 720 kilometres that will demonstrate “true solar sailing.”

The Planetary Society is collaborating on the project with California Polytechnic State University and the Georgia Institute of Technology, which will help collect data from the spacecraft, and two private space technology companies, Stellar Exploration Inc., which built the spacecraft, and Ecliptic Enterprises Corp., which conducted flight testing.

Five years later, the first solar sails were deployed by Japan’s Venus-bound IKAROS spacecraft and NASA’s NanoSail-D satellite in low-Earth orbit.

NASA has two upcoming solar sail missions, one to the moon and the other to an asteroid, scheduled for 2018.

Electric bacteria connect to form wires

Microbiologists from California have discovered bacteria that survive by eating pure electrons rather than food, bringing an entirely new method of existence to awareness and raising questions about possibilities for alien life.

According to Extreme Tech, the ‘electric bacteria’ – as they have been dubbed by the team that discovered them – take energy from rocks and metal by feasting directly on their electrons. The hair-like filaments the bacteria produce carry electrons between the cells and their environment.

These bacteria yet again prove the almost miraculous tenacity of life — but, from a technology standpoint, they might also prove to be useful in enabling the creation of self-powered nanoscale devices that clean up pollution. Some of these bacteria also have the curious ability to form into ‘biocables,’ microbial nanowires that are centimeters long and conduct electricity as well as copper wires — a capability that might one day be tapped to build long, self-assembling subsurface networks for human use.

As you may recall from high school biology, almost every living organism consumes sugar to survive. When it gets right down to it, everything you eat is ultimately converted or digested into single molecules of glucose. Without going into the complexities of respiration and metabolism (ATP!), these sugars have excess electrons — and the oxygen you breathe in really wants those electrons. By ferrying electrons from sugar to oxygen, a flow of electrons — i.e. energy — is created, which is then used to carry out various vital tasks around your body (triggering electrons, beating your heart, etc.)

These special bacteria, however, don’t need no poxy sugars — instead, they cut out the middleman and feed directly on electrons. To discover these bacteria, and to cultivate them in the lab, the USC biologists quite simply scooped up some sediment from the ocean, took it back to the lab, stuck some electrodes into it, and then turned on the power. When higher voltages are pumped into the water, the bacteria “eats” electrons from the electrode; when a lower voltage is present, the bacteria “exhales” electrons onto the electrode, creating an electrical current (which could be used to power a device, if you were so inclined). The USC study very carefully controlled for other sources of nutrition — these bacteria were definitely eating electrons directly.

 All told, various researchers around the world have now discovered upwards of 10 different kinds of bacteria that feed on electricity — and, interestingly, they’re all pretty different (they’re not from the same family), and none of them are like Shewanella or Geobacter, two well-known bacteria that have interesting electrical properties. Kenneth Nealson of USC, speaking to New Scientist about his team’s discovery, said: “This is huge. What it means is that there’s a whole part of the microbial world that we don’t know about.

As for the repercussions of finding bacteria that eat and excrete electrons, the most obvious use is in the growing fields of molecular motors and nanomachines. These bacteria, at their most basic, are machines that consume raw electricity — and so, with some clever (genetic?) engineering, it stands to reason that we might one day use them to power tiny machines that can perform tasks that are currently carried out by expensive, human-operated machines (cleaning up chemical spills, for example). These bacteria might also allow us to find out exactly how much energy a living cell needs to survive; put them in a test tube, and then slowly dial back the electrode voltage until they die. A cruel experiment, but one that would yield very informative results.