There are no electrical outlets in space. No gas stations, either. For space explorers hovering in the cold, airless regions beyond our atmosphere, power (or the lack thereof) is a matter of life and death. Thanks to our sun, however, solar power is readily available.
Solar technologies generate a majority of the power used during space missions, keeping life support and other vital spacecraft systems working. Solar power is so critical that NASA spends considerable time and money to make solar panels must more efficient, lightweight and affordable.
You don't have to look far to see how important solar power is to NASA. Just gaze skyward. One of humankind's most ambitious projects, the ISS (International Space Station) is dwarfed by the size of its eight 114-foot (35-meter) long solar array wings. Each wing contains around 33,000 solar cells, which convert about 14 percent of the sunlight that hits them into usable energy [source: NASA]. That may not sound very efficient, but even after life support and other vital functions have the power they need, there's still enough juice to power the equivalent of dozens of homes on Earth [source: Shuttle Press Kit].
But the ISS features decades-old technology. Thanks to NASA's research and development teams, contemporary solar power designs are significantly better than those aboard the ISS. In fact, NASA has an entire division, called the Photovoltaic & Space Environments Branch, dedicated to addressing solar power and related challenges. This branch actively partners with private companies and shares scientific knowledge in the hopes of accelerating technological developments.
This knowledge-sharing strategy works. In 1989, NASA partnered with Iowa Thin Film Technologies, Inc. (now PowerFilm, Inc.). PowerFilm devised a way to incorporate paper-thin solar cells onto flexible sheets that can be rolled up for storage. The film is incredibly efficient, too, converting 90 percent of the light that strikes its surface into energy [source: NASA].
In other words, these are nothing like antiquated solar cells from the 1970s. Today's solar cells and associated products are getting better all the time. Keep reading to see how NASA's investments are improving solar power for space missions -- and for those of us stuck on the mother planet, too.
Here Comes the Sun
Continued improvements to solar power are imperative to future space travel. As missions blaze farther and farther into deep space, sunlight wanes. A 1-meter square (3.2-foot) solar panel that produces about 400 watts near Earth would have to be 2,000 times bigger to generate the same amount of power in Pluto's neighborhood [source: NASA].
Thankfully, there are other promising products in development. Another NASA partner, MSGI Technology Solutions, recently unveiled solar cells that incorporate tiny carbon pillars, called nanotubes, into the solar cell design.
The nanotubes help reduce reflected light, using the pillars to snag photons that would bounce off of a traditional flat panel. Also, the nanotubes increase the surface area of the panel, giving the product more room to capture light and produce more energy.
That's not all. Solar panel makers also face problems associated with dust and dirt. A tiny dust deposit of 0.1 ounce (2.8 grams) of dust per square yard (0.9 meters) can reduce solar panel efficiency by as much as 40 percent. That's why NASA employees working with non-NASA scientists developed a dirt-repelling coating for the panels, which was first developed for use in space environments [source: Solar Power Engineering].
The so-called self-cleaning panels have a thin, transparent and electrically conductive layer. When embedded sensors detect accumulated dust, a cascading electrical charge is sent through the coating, in effect pushing the dirt off with electromagnetic waves.
This kind of cleaning technology is critical for two reasons. One, it's not based on mechanical, moving parts, which would be prone to breakdowns. And two, it doesn't require hand washing, a painstaking chore that would devour far too much time and clean water, especially if the panels were installed in a very remote, dusty location -- say, for instance, on the surface of Mars.
All of these advancements to solar power are relevant here on Earth, too. A multitude of consumer products, from toys and camping gear to radios, now use modernized solar panels. Solar advancements are applicable on a larger scale as well and could even help us energize a totally new type of power plant.
In the early 2000s, NASA and some private companies were seriously considering space solar power systems. In theory, satellites equipped with huge solar panel arrays would collect sunlight and beam its energy down to power stations on Earth. Although NASA isn't currently pursuing the concept, other countries (such as Japan) are, and we'll undoubtedly see even more improvements to solar tech as a result.
As you can see, without NASA's involvement, solar power technology would likely still be a fledgling science. But thanks to enterprising NASA scientists and private entrepreneurs, sun-powered products will continue to improve, both in space and on Earth.
Do you know how WISE works? Learn about its new purpose to look for near-Earth objects like asteroids at HowStuffWorks.
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