The Future of Solar: The Space-Based Solar Farm

space-solar-headThe nation of Japan has long been regarded as being at the forefront of emerging technology. And when it comes to solar energy, they are nothing if not far-sighted and innovative. Whereas most nations are looking at building ground-based solar farms in the next few years, the Japanese are looking at the construction of vast Lunar and space-based solar projects that would take place over the course of the next few decades.

The latest proposal comes from the Japan Aerospace Exploration Agency (JAXA), which recently unveiled a series of pilot projects which, if successful, should culminate in a 1-gigawatt space-based solar power generator within just 25 years. Relying on two massive orbital mirrors that are articulated to dynamically bounce sunlight onto a solar panel-studded satellite, the energy harvested would then be beamed wirelessly to Earth using microwaves, collected Earth-side by rectifying antennas at sea, and then passed on to land.

lunaringJAXA has long been the world’s biggest booster of space-based solar power technology, making significant investments in research and rallying international support for early test projects. And in this respect, they are joined by private industries such as the Shimizu Corporation, a Japanese construction firm that recently proposed building a massive array of solar cells on the moon – aka. the “Lunar Ring” – that could beam up to 13,000 terawatts (roughly two-thirds of global power consumption) to Earth around the clock.

Considering that Japan has over 120 million residents packed onto an island that is roughly the size of Montana, this far-sighted tendency should not come as a surprise.  And even before the Fukushima disaster took place, Japan knew it needed to look to alternative sources of electricity if it was going to meet future demands. And considering the possibilities offered by space-based solar power, it should also come as no surprise that Japan – which has very few natural resources – would look skyward for the answer.

solar_array1Beyond Japan, solar power is considered the of front runner of alternative energy, at least until s fusion power comes of age. But Until such time as a fusion reaction can be triggered that produces substantially more energy than is required to initiate it, solar will remain the only green technology that could even theoretically provide for our global power demands. And in this respect, going into space is seen as the only way of circumventing the problems associated with it.

Despite solar power being in incredible abundance – the Earth’s deserts absorb more energy in a day than the human race uses in an entire year – the issue of harnessing that power and getting it to where it is needed remain as stumbling blocks. Setting up vast arrays in the Earth’s deserts would certainly deal with the former, but transmitting it to the urban centers of the world (which are far removed from it’s deserts) would be both expensive and impractical.

space-based-solarpowerLuckily, putting arrays into orbit solves both of these issues. Above the Earth’s atmosphere, they would avoid most forms of wear, the ground-based day/night cycle, and all occluding weather formations. And assuming the mirrors themselves are able to reorient to be perpetually aimed at the sun (or have mirrors to reflect the light onto them), the more optimistic estimates say that a well-designed space array could bring in more than 40 times the energy of a conventional one.

The only remaining issue lies in beaming all that energy back to Earth. Though space-based arrays can easily collect more power above the atmosphere than below it, that fact becomes meaningless if the gain is immediately lost to inefficiency during transmission. For some time, lasers were assumed to be the best solution, but more recent studies point to microwaves as the most viable solution. While lasers can be effectively aimed, they quickly lose focus when traveling through atmosphere.

spaceX_solararrayHowever, this and other plans involving space-based solar arrays (and a Space Elevator, for that matter) assume that certain advances over the next 20 years or so – ranging from light-weight materials to increased solar efficiency. By far the biggest challenge though, or the one that looks to be giving the least ground to researchers, is power transmission. With an estimated final mass of 10,000 tonnes, a gigawatt space solar array will require significant work from other scientists to improve things like the cost-per-kilogram of launch to orbit.

It currently costs around $20,000 to place a kilogram (2.2lbs) into geostationary orbit (GSO), and about half that for low-Earth orbit (LEO). Luckily, a number of recent developments have been encouraging, such as SpaceX’s most recent tests of their Falcon 9R reusable rocket system or NASA’s proposed Reusable Launch Vehicle (RLV). These and similar proposals are due to bring the costs of sending materials into orbit down significantly – Elon Musk hopes to bring it down to $1100 per kilogram.

So while much still needs to happen to make SBSP and other major undertakings a reality, the trends are encouraging, and few of their estimates for research timelines seem all that pie-eyed or optimistic anymore.

Sources: extremetech.com, (2)

News From SpaceX: Falcon 9 Completes Second Test Flight

falcon-9-reusable-test2In yet another impressive feat from Elon Musk’s private space company, the Falcon 9 Reusable Rocket completed it’s second test on Friday April 2nd, 2014. In this latest test of the reusable rocket system, the Falcon 9 effectively quadrupled its height from its last test. Having reached 250 meters during its last test flight, the rocket now reached a full kilometer and then descended safely back to Earth and achieving a soft landing.

This comes just two weeks after SpaceX launched one of its Falcon 9’s on a supply mission to the ISS, which included the soft landing of its stage one rocket. Unfortunately, high sea waves prevented a boat from meeting the rocket on its ocean-based pad. And so, the rocket landed in the ocean, hovering for a few seconds before toppling into the sea. Still, the fact that the rocket was able to make it back to just above sea level was good news, and confirms that SpaceX is that much closer to the dream of reusability.

spacex-falcon-9-rocket-largeIn the coming months, SpaceX plans to conduct more tests. In addition to reaching higher altitudes, they will also be testing the rocket’s retractable landing legs, and working more with unpowered guidance. According to the description that came with the recently-released video of the 1000m test:

F9R test flights in New Mexico will allow us to test at higher altitudes than we are permitted for at our test site in Texas, to do more with unpowered guidance and to prove out landing cases that are more-flight like.

This is also good news for NASA, which officially announced the cessation of cooperation with the Russian Federal Space Agency in early April. While their inability to rely on Russian Soyuz rockets to send astronauts into orbit (and bring them home) has allowed NASA to apply greater pressure on the federal government to fund its Reusable Launch Vehicle (RLV) system. However, Russian Deputy Prime Minister Dmitry Rogozin had a more mocking suggestion.

NASA_trampolineAfter initially joking that American astronauts would be left stranded on the ISS, he also recommended that NASA try using a trampoline to reach orbit. The joke was naturally irrelevant, since day-to-day operations involving the ISS are not going to be affected by these sanctions. Still, the inability to rely on Russian Soyuz’s in the near future will mean that US satellites – which are used for everything from GPS to spying – will be undeployable for the time being.

It also means that orbit conducted in Low-Earth Orbit will be complicated. As such, a reusable rocket system, be it NASA’s own or an external contractor’s (in this case, SpaceX) will give the US sanctions against Russia additional weight. It will also ensure that the dream of cost-effective space travel, which is intrinsic to everything from colonizing the Moon and Mars to establishing a Space Elevator and asteroid mining, will be become a reality in the not-too-distant future.

The sky is no longer the limit, people! And be sure to enjoy this video of the F9R 1000 meter test flight.


Source: 
space.IO9.com, (2)

News from Space…X: Reusable Launch Vehicle Good to Go!

spacex-falcon-9-octaweb-640x427After years of research, development and testing, SpaceX (Elon Musk’s poster child of the commercial space travel revolution) is about to attempt something truly revolutionary. In a bid to significantly reduce the costs of sending rockets into space, they will attempt the first ever soft landing of a heavy space launch vehicle. Initially planned for March 16th, the company has since updated the launch date to March 30th in order to give its techs more time to prepare.

On this day, if all goes according to plan, SpaceX mission CRS-3 will lift off from Cape Canaveral on a resupply mission to the International Space Station. In the past, rockets blasting off from Earth would normally ditch the massive primary stage of their assembly into the ocean after launch. But this one it will sprout some metal legs and use what’s left of its rocket fuel to slowly return to Earth.

spacex-falcon-9-rocket-largeThis is perhaps the single most important step in SpaceX’s stated goal of reducing the cost of space travel by a factor of ten or more, which will ensure the acceleration of space travel for the indefinite future. One of the primary reasons that the human exploration of space is moving so slowly is the cost factor. For heavy lift vehicles, which are required to lift large satellites, equipment, and supplies into space, it costs roughly $22,000 to lift a single kilogram ($10,000 per pound) into orbit.

It costs even more to send a rocket beyond Earth’s gravity well and out into space, which is why reducing costs is seen as intrinsic to sending manned missions to Mars. Currently, NASA pays around $70 million per seat aboard the Soyuz space capsule, thanks to the cancellation of the Space Shuttle Program in 2011. But a crewed version of SpaceX’s Dragon capsule, DragonRider, is also in development, which will reduce the cost per seat to $20 million.

spacex-dragon-capsule-grabbed-by-iss-canadarm-640x424SpaceX debuted its Reusable Launch Vehicle (RLV) tech on the suborbital Grasshopper rocket in October of 2013. This came after multiple launches were conducted that saw the rocket reach greater and greater altitudes and which tested its ability to maneuver horizontally. Once this was complete, they began the task of fitting a Falcon 9 with the Merlin rocket engines, which would bring the vehicle back to Earth after the first stage rocket detached.

For this flight, the first stage will still land in the water to minimize the chance of damage if something goes wrong. But once SpaceX is confident that it can do a soft landing with its RLV safely, future launches will see the first stage fly all the way back to to the launchpad. After that, SpaceX will start bringing the second stage back to the launchpad, too. The eventual goal, according to SpaceX, is to create a launch system that is reusable within “single-digit hours.”

grasshopper_lateraldivertBasically, SpaceX would give these rockets a quick once-over, fill them back up with fuel, and send them back to work. If everything goes to plan, the total cost per pound to launch into Earth orbit could drop to $500 or less — one twentieth of what unreusable rockets cost. Suffice it to say, if SpaceX manages to undercut every other space launch company in the world — including the Russian and Chinese governments — it could suddenly find itself in a very powerful and lucrative position.

Not only would it replace Russia and the Ukraine as NASA’s primary contractor, it would also see to the restoration of America’s ability to send people, equipment, satellites and supplies into space from its own soil. Given the current state of tensions in the Crimea, this is sure to put a smile on a lot of people’s faces in DC. The launch is currently scheduled to take place at the end of March and there will be a live NASA feed to cover the rocket’s descent.

And while we’re waiting, here’s a clip of SpaceX first testing out the Grasshopper rocket to take us back:


Sources:
technologyreview.com, extremetech.com