OSTP: NASA take lead in R&D

From: http://www.space.com/news/white-house-plans-asteroid-impact-101021.html
U.S. Must Be Ready to Meet Asteroid Threat, White House Science Adviser Says
By Jeremy Hsu
SPACE.com Senior Writer
posted: 21 October 2010
11:16 am ET
National emergency plans for natural disasters can also work in the unlikely scenario of an asteroid strike on the U.S., according to a letter to Congress by the White House's top science adviser, SPACE.com has learned.

The 10-page letter by John Holdren, director of the White House Office of Science and Technology Policy, adds that the U.S. has a responsibility to the world as the country most capable of detecting space rocks that threaten Earth. The Oct. 15 letter obtained by SPACE.com is addressed to the leaders of the House Committee on Science and Technology.

Holdren states that NASA must continue leading efforts to close the gap in detecting and perhaps deflecting near-Earth objects (NEO). The U.S. space agency already has the duty of alerting the rest of the government about any threatening space objects.

Holdren's letter also laid out the duties of other federal agencies in handling emergency communications and response. It called for a "senior-level interagency simulation exercise" to test impact-response plans before the United States is confronted with an actual asteroid impact.

"My immediate reaction is that it represents the most detailed consideration of the U.S. government's response to the NEO threat to date, more clearly delineating communication links and responsibilities than had previously been the case," said Clark Chapman, space scientist at the Southwest Research Institute in Boulder, Colo.

Going on alert

According to Holdren's letter, the Federal Emergency Management Agency, under the Department of Homeland Security, has the main responsibility on the ground in the U.S. FEMA can rely in part upon the National Warning System, which was designed to alert U.S. citizens to a Cold War nuclear attack.

The Department of Defense would work with NASA on possible mitigation or deflection scenarios that involved military resources.

Meanwhile, the Department of State would help coordinate any international warnings or responses in a deep-impact scenario that affects more than just the U.S. It has experience notifying other countries about re-entering human-made space objects, including the defunct USA-193 spy satellite that was ultimately destroyed by a U.S. Navy missile.

"The United States is currently the world leader in NEO detection activities and will have a vital role to play in such communications, irrespective of whether the direct risk to the United States or its territories is considered low," Holdren said.

A NASA advisory council recently suggested that the space agency set up an official Planetary Defense Coordination Office to lead protection efforts against threatening asteroids or comets.

Finding the threat

NASA has begun closing in on its congressionally directed goal of finding at least 90 percent of all NEOs with a diameter of 1 kilometer or greater. Search teams had discovered about 903 of an estimated 1,050 NEOs in that size category as of Oct. 1, and the space agency plans to reach its 90 percent detection goal by the end of this year.

Just 149 of the discovered objects have orbits that could possibly bring them into collision with Earth, and none present an impact threat within the next 100 years. Another 993 objects less than one kilometer in diameter also have orbits that could someday pose a threat to our planet.

Yet NASA estimates that the 6,416 known NEOs in the smaller size category, less than 1 kilometer wide, represent just five percent of the expected count. In other words, there are probably many more objects out there that represent a possible threat to Earth.

Facing the future

Some of those objects were discovered more recently by NASA's sky-mapping WISE mission, which is slated to end in January 2011. But there are possible plans for ground-based telescopes that could join the hunt, such as the Air Force's Space Surveillance Telescope and the Large Synoptic Survey Telescope.

The National Research Council and NASA also suggested the possibility of a dedicated asteroid hunter that would fly in a Venus-trailing orbit. No firm plans have been made for this.

President Barack Obama's new National Space Policy and plan for human spaceflight has also targeted a human mission to an asteroid by 2025. That could prove a useful dry run of sorts for any future efforts that might need to deflect an asteroid away from Earth.

"The planning, required capabilities, and ultimate execution of such a mission also would parallel most aspects of a potential robotic asteroid-deflection mission, providing valuable experience in asteroid-rendezvous techniques," Holdren said.

SPACE.com's Space Insider Columnist Leonard David contributed to this report from Las Cruces, N.M.

From: http://www.nature.com/news/2010/101021/full/news.2010.554.html
NASA to lead global asteroid response
Agency's monitoring role boosted to include warning and R&D on defence capability.

Eugenie Samuel Reich
NASA is to be charged with helping to avert a hit from a space rock.JULIAN BAUM / SCIENCE PHOTO LIBRARY
NASA will play a leading part in protecting the United States and the world from the threat of a dangerous asteroid strike, according to letters sent by John Holdren, director of the White House Office of Science and Technology Policy (OSTP), to Congressional committee leaders on Friday.

Holdren's letters to the Senate Committee on Commerce, Science, and Transportation and the House Committee on Science and Technology assign responsibilities to the US space agency that go beyond its 2005 Congressional mandate to detect and track 90% of potentially hazardous asteroids with a diameter greater than 140 metres. To date the agency has found 903 of the estimated 1,050 asteroids with diameters of a kilometre or more passing within about 50 million kilometres of the Earth.

NASA will be mandated to notify other organizations, including the US Federal Emergency Management Agency (FEMA), if a dangerous asteroid is found, and to drive research and development on the capability needed to deflect the rock.

In assigning NASA's new asteroid defence role by 15 October, Holdren was meeting a requirement of the 2008 NASA Authorization Act. Under the act OSTP is also required to choose an agency or agencies that would protect the United States and implement a deflection, if one were necessary.

Ramping up funds

So far, NASA's mandate to track near-Earth objects has been largely unfunded.

Former US astronaut Russell 'Rusty' Schweickart, who has advocated for the United States and other countries to be more active in planetary defence against asteroids, says that NASA's amplified responsibilities give it a platform for asking Congress for extra funds. "This is a major step forward," he says. Schweickart co-chairs NASA's Ad-Hoc Task Force on Planetary Defense, set up by the agency in March with the expectation that it would be assigned a leading role in coordinating asteroid defence (see 'NASA panel weighs asteroid danger').

“This is a major step forward.”

Holdren also envisions a key role for FEMA in passing along news of the impending strike to states and territories that could be affected. "The essence of the planned notification approach is to utilize existing communications resources and mechanisms resident at FEMA," he wrote in the letters.

The letters add that NASA would make additional notifications through the US State Department and diplomatic channels to other countries that could be affected, and to the United Nations. Those notifications would be updated by NASA as more information became available about the threat, up until one day in advance of the projected impact, Holdren says.

Strategic defense

The ad-hoc task force released a report on 6 October listing actions NASA should take on planetary defence. It recommended the establishment of a Planetary Defense Coordination Office, with an annual budget of around US$250 million, and the initiation of a mission to prove capability to deflect an asteroid.

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Holdren notes in his letters that the President's budget for the 2011 fiscal year asks for a three-fold increase in funds for near-Earth object detection activities, from $5.8 million to $20.3 million. It remains to be seen whether next year's budget request will cater for the agency's additional responsibilities. "It's especially important that those activities discussed by the OSTP be supported by a proposed budget to cover those modest costs required," says Tom Jones, another former astronaut and co-chair of the ad-hoc task force.

Despite being fairly specific about notification procedures, Holdren's letters were much vaguer about the methods for deflecting an asteroid on a collision course with Earth. He says that the US government's assessment of deflection options is still at an early stage.

"As NASA tests in space the techniques and technologies needed for deflection, the OSTP should re-examine this question and identify the lead agency — or agencies — to actually execute a deflection demonstration," says Jones.

Does SSP have supporters? See this list:

Who has been supportive of establishing a program in SSP, and what they have said in public:

1) From the Space Enterprise Council (SEC) [then under US Chamber] white paper, 2008:
…the urgency of energy needs requires ongoing Federal investment in a balanced portfolio of alternative energy research programs, which should include study of SBSP. Major technical progress already achieved in SBSP-related technologies strengthens the case for including SBSP in the mix of alternative sources to explore...Beyond enhancement of energy production per se, SBSP might help create new economic opportunities through resultant technology advances in space launch, space utilization, and technological spin-offs applicable to a host of materials and processes...For example, SBSP research might lead to improvements in the efficiency of solar cells that power communications satellites, as well as power management systems for terrestrial solar power systems...Also, to the extent that SBSP is integrated into terrestrial solar power production, development of SBSP ground infrastructure might generate revenue even before deployment of systems in space. In this and related applications, SBSP could emerge as an enhancement for, rather than a competitor with, terrestrial solar power generation.
http://www.nss.org/settlement/ ssp/library/2008- SECSpaceBasedSolarPowerWhitePa per.pdf

2) From the Abbey-Lane / Baker Institute Report, Maximizing NASA's Potential In Flight and On the Ground: Recommendations for the Next Administration, 2009:

Recommendation 3: Deliver longer-term payoffs (within four to eight years) for energy and the environment…As a potential long-term energy solution, an effort would be made to demonstrate—initially on a small scale—wireless power transmission from space to Earth using shuttle and ISS…this concept has made major strides since its inception …Demonstrating space solar power on a small scale would help us better understand what would need to be done to utilize this concept for electrical power needs.
http://www.bakerinstitute.org/ publications/SPACE-pub- ObamaTransitionAbbeyLaneMurato re-012009.pdf

3) From the Buzz Aldrin / ATWG Policy Statement on NSS Blog
Bush VSE missed (or lacked) almost entirely any strategic vision and goals for supporting and enabling space-based human economic expansion or industrialization in space.
…proposed cabinet-level U.S. Department of Space (DOS), as discussed earlier, should manage and take charge of the government functions of supporting and incubating space-based industrial capability and transportation infrastructure development
…investing in SBSP (space based solar power) and space tourism infrastructures as a significant part of the national space economy and energy programs—is the choice of a strategic space goal that certainly will re-ignite the American spirit
http://blog.nss.org/?p=360

4) National Space Society (NSS), [largest Space Advocacy organization] Position Paper

The National Space Society believes that one of the most important long-term solutions for meeting those energy needs is Space Solar Power (SSP), which gathers energy from sunlight in space and sends it to Earth. We believe that SSP can solve our energy and greenhouse gas emissions problems.
http://www.nss.org/ legislative/positions/NSS-SSP- PositionPaper.pdf

5) The Space Frontier Foundation (SFF) [most significant space entrepreneur organization] Position
A fundamental challenge in this century is how to provide for the world's growing energy needs. In meeting this challenge, it is vital that we protect the Earth's fragile biosphere. Space Solar Power, or SSP, may be part of the energy solution. SSP could be an environmentally friendly economical energy producing technology that simultaneously promotes the human realization that the Earth is an open system and the human settlement of space.
http://space-frontier.org/ Projects/spacesolarpower/

6) The American Institute of Aeronautics and Astronautics (AIAA), the premier world aerospace technical society Policy Paper

The SPS is one of several potentially competitive options for providing a nondepletable source of baseload electric power in the future…The SPS appears to be technologically feasible.
http://pdf.aiaa.org// downloads/ publicpolicypositionpapers// SolarSats-1978.pdf

7) The report of the DoD/NSSO (the only interagency and independent voice for space security) Study Group's 2007 Report:

Space-Based Solar Power does present a strategic opportunity that could significantly advance US and partner security, capability, and freedom of action, and merits significant further attention on the part of the United States Government and the private sector...The SBSP Study Group concluded that SBSP requires a coordinated national program with high-level leadership and resourcing commensurate with its promise, but at least on the level of fusion energy research or International Space Station construction and operations...The SBSP Study Group concluded that should the U.S. begin a coordinated national program to develop SBSP, it should expect to find that broad interest in SBSP exists outside of the US Government, ranging from aerospace and energy industries; to foreign governments such as Japan, the EU, Canada, India, China, Russia, and others; to many individual citizens who are increasingly concerned about the preservation of energy security and environmental quality. While the best chances for development are likely to occur with US Government support, it is entirely possible that SBSP development may be independently pursued elsewhere without U.S. leadership.
http://www.nss.org/settlement/ ssp/library/final-sbsp- interim-assessment-release-01. pdf

8) The Department of Commerce, Office of Space Commercialization website currently reads:
As society seeks to identify and develop alternative energy sources for the future that are clean, safe, and continuously available, the concept of space-based solar power (SBSP) is beginning to gain traction as a potential answer to the world's long-term energy needs.

http://www.space.commerce.gov/ power/

9) The Change.gov Visionary White Paper, one of the first 10 circulated by the transition team on Change.gov:

The U.S. federal government has invested over $21 Billion in fusion research in the last 50 years, and the DOE is currently spending $300 million per year on fusion energy research. When choosing a lead agency for SSP, the Administration should establish an SSP research budget within that agency that grows to at least the level of the DOE’s fusion energy research program.
http://change.gov/open_ government/entry/space_solar_ power_ssp_a_solution_for_ energy_independence_climate_ change

10) Spacefaring America White Paper on The End of Easy Energy and What to Do About It:
This paper’s assessment of the energy production potential of conventional nuclear, geothermal, wind, ground solar electric, and land biomass finds that these will fall significantly short of both the U.S.’s or the world’s 2100 sustainable energy needs. To fill the substantial sustainable energy shortfall that will emerge by 2100 as the era of easy energy ends, space solar power and algae biodiesel—absent the extensive use of advanced nuclear energy and/or undersea methane hydrates—will need to be substantially developed. Space solar power will be needed to supply most of the U.S.’s and the world’s dispatchable electrical power generation.
http://mikesnead.net/ resources/spacefaring/white_ paper_the_end_of_easy_energy_ and_what_to_do_about_it.pdf

11) Naval Research Lab Report, 2008
The NRL SBSP Study Group concurs with the conclusions of the numerous previous studies
of preceding decades that the SBSP concept is technically feasible but that there remain significant system risks in many areas...The Group concurs that SBSP offers one of several possible solutions to the energy independence and dominance of our country and our military; and that those alternative solutions (including terrestrial solar, nuclear, and wind) must be an integral part of the solution
http://www.nss.org/settlement/ ssp/library/2008-NRLSBSP- PossibleDefenseApplicationsAnd Opportunities.pdf

12) Dr. Kalam, at the time India's President, and national hero as their lead rocket scientist from both their civil and military programs, address to Boston University on the Future of Human Space Exploration:
However solar flux on earth is available for just 6-8 hours every day whereas incident radiation on space solar power station would be 24 hrs every day. What better vision can there be for the future of space exploration, than participating in a global mission for perennial supply of renewable energy from space?...Space based solar power stations have six to fifteen times greater capital utilization than equivalent sized ground solar stations. Linking Space solar power to reverse osmosis technology for large-scale drinking water supplies could be yet another major contribution of Space.
http://www.rites.com/rites- journal/A.P.J.Abdul%20kalam. pdf

13) The Aeronautical Society of India (AeSI) 2007 conference recommendations:
…generate a national consensus for the Global Aerospace and Energy initiative, determine the sources and uses of funding, and evolve a suitable management structure and system to plan and implement the mission
http://www.aesi-hyd.com/ conference07/Panel_ recommendation.htm

14) Interview with Hiroaki Suzuki with the Japan Aerospace Exploration Agency, also known as JAXA. He is one of 180 Japanese scientists working on the program, according to Scientific American.
We expect space solar panel systems will be competitive with the existing power plants in 20 to 30 years, if the space transportation cost is considerably reduced. It should be noted that solar systems do not emit CO2, nor do they create nuclear waste...We are proposing a roadmap that consists of a stepped approach to achieve 1-gigawatt-class commercial space solar panel systems in 20 to 30 years. That means 2030 would see the very beginning of commercial systems. We expect the ultimate percentage of electricity derived from space will be more than several tens of percent. By the way, Japanese total electricity generation was about 275 gigawatts or 990,000 gigawatt-hours in 2005.
http://energycentral. fileburst.com/EnergyBizOnline/ 2008-5-sep-oct/Tech_Frontier_ Solar_Space.pdf

15) ESA Advanced Concepts project summary page:
The big advantage of space based solar power collection is the 24h availability: unlike the situation on the surface of Earth, in geostationary orbit there is no night and the sun is never shadowed by clouds, rain or fog...We are therefore currently studying how e.g. space assets might best integrate into the management of future, complex energy grids with large components of renewable energy plants.
http://www.esa.int/gsp/ACT/ nrg/op/SPS/index.htm http://www.esa.int/gsp/ACT/ nrg/index.htm

16) The Space Solar Alliance for Future Energy (SSAFE) press release:
The Space Solar Alliance for Future Energy (SSAFE), a new organization advocating investment in space-based solar power technologies to address the planet’s future energy needs, was announced today at the National Press Club. The coalition of thirteen leading research organizations and space advocacy groups focused their inaugural event on the announcement of a new study of space-based solar power led by the National Security Space Office (NSSO)...The new Space Solar Alliance for Future Energy (SSAFE) will promote the findings of the NSSO-led study, and seek to communicate the benefits of the technology to business, government and the general public...The founding members of SSAFE are the National Space Society, Space Frontier Foundation, Space Power Association, Aerospace Technology Working Group, Marshall Institute, Moon Society, ShareSpace Foundation, Space Studies Institute, Spaceward Foundation, AIAA Space Colonization Technical Committee, ProSpace, Space Enterprise Council, and Space Generation Foundation.
http://ssafe.wordpress.com/

17) Aerospace Technology Working Group (ATWG) Recommended Actions Paper, 2008

We judge this is not a NASA-centric aerospace technological issue. It is a national security issue, an energy security issue, an environmental solution, and an economic security issue, and, thus, needs to be addressed within a framework that includes all these dimensions, perspectives, and players, including considerable participation by private energy enterprise. The role of government should be to mature a limited number of components and processes to prove their economic and technical viability; then, step back, while continuing to support a strategy that addresses all elements of the problem. The government should lend support to this potential new industry, as done before for other fuel sources. While completing the maturing phase, the government program should work with industry to collaborate so that the private sector can pick up the costs and implement the SBSP system, if practical. This can be done in a sequence of steps with each step creating an increasing level of energy production to meet legitimate market demand profitably step by step, ultimately scaling to the level of provision of significant base load power in the U.S.http://www.atwg.org/ public/ATWG%20space-based% 20solar%20power.pdf

18) Taylor Dinerman in Space Review

In Washington lots of people have complained that the Obama Administration has so far not given the India-US relationship the attention it deserves... The one area in which there seems to be movement on, though, is a “renewable energy partnership”...Any analysis of the potential of terrestrial solar energy in India or elsewhere runs up against the awesome size of the future demand for power...they cannot by any stretch of the imagination fulfill the requirements of a huge growing economy like India’s. ...Only SSP, which operates 24 hours a day, 7 days a week, year after year, can hope to meet this need....Fortunately both India and the US have space programs and technologies that could, if developed together and possibly with other interested nations such as Japan, bring SSP systems into service sometime late next decade or the early 2020s. With its commitment to develop a new low cost reusable spaceplane, the India Space Research Organisation (ISRO) is already working on one of the key technologies needed for an SSP system. Indian participation in both private and public SSP programs should be welcomed by the US. In the near term the new Indo-US renewable energy partnership would seem to be the right place to start this collaboration. Together the partners can identify what will be needed in the way of technological and scientific investments over the next decade in order to make SSP a reality. India has lots of talent that can be committed to this effort and so does the US. In fact, the kind of ambitious idealism that we saw at NASA during the Apollo years could be engendered by this goal. Safe, clean, abundant energy from the Sun is not an impossible dream. The technology has not been perfected and the need for new, low-cost Earth-to-orbit transportation systems is as urgent as ever, but there are no requirements for any scientific breakthroughs.

http://www.thespacereview.com/article/1389/1

Will Space-Based Solar Power Finally See the Light of Day?

This is one of the best, most comprehensive articles written on the subject. Kudos to Adam Hadhazy and SCIAM!
Scientific American: Features - April 16, 2009
Will Space-Based Solar Power Finally See the Light of Day?
A satellite that reaps the sun's energy in space and beams it down to Earth for use as electricity may leave the realm of sci-fi and edge closer to reality this week following an energy deal in California
By Adam Hadhazy
Pacific Gas & Electric Co. (PG&E) has long invested in renewable energy sources, including geothermal, wind and solar. Earlier this week, the utility company reached for the stars in announcing the first-ever deal of its kind: The California power utility, says spokesperson Jonathan Marshall, plans to purchase clean energy generated by a satellite beaming solar power from orbit.The agreement between PG&E and Solaren Corp., an eight-year-old company based in Manhattan Beach, Calif., still hinges on state regulatory approval. If the deal gets the green light, Solaren must then privately raise billions of dollars to design, launch and operate a satellite as well as an energy-receiving ground station slated for the Fresno County area, says Cal Boerman, director of energy services for Solaren.The challenges of building this satellite (due to be completed in 2016) and introducing so-called space-based solar power (SBSP) remain formidable. But driven by the urgency of climate change and the lowering costs of solar technology, a growing number of countries and companies believe an energy revolution could be in the offing.Why bother harvesting solar energy directly from space? It is abundant, and "you can get [this] power 24/7," says Marty Hoffert, an emeritus professor of physics at New York University. Sunlight is some five to 10 times stronger in space, and its shine would reach energy-gathering satellites placed into geostationary (fixed) orbits—the realm of many currently deployed communications spacecraft—more than 99 percent of the time.SBSP could, according to energy experts, provide constant, pollution-free power—unlike intermittent wind and cloud cover–sensitive ground-based solar, and without the emissions of fossil fuels or radioactive waste from nuclear power. "[SBSP] is a disruptive technology [in that] it could change the whole energy equation," says Frederick Best, director of the Center for Space Power (CSP) at Texas A&M University in College Station, Tex.The premise (and promise) of SBSP has been considered scientifically feasible since the late 1960s. The basic concept of beaming microwave frequencies to Earth from orbit has already been proved: A fleet of solar-powered communication satellites routinely beam various electromagnetic frequencies to ground receivers, linking cell phone calls or relaying TV signals to rooftop dishes, for example. Converting solar energy beamed from space into electricity in a power grid, however, has not yet been demonstrated.Space Energy, a Switzerland-based SBSP start-up, aims to change that by deploying a prototype orbiter in the next several years, possibly before Solaren's pilot plant reaches orbit. "You can argue the physics [of SBSP] all day, but you'll only know with a prototype," says Peter Sage, a co-founder of Space Energy, started in 2008.Last year, U.S. and Japanese researchers crossed an important SBSP threshold when they wirelessly transmitted microwave energy between two Hawaiian islands about 90 miles (145 kilometers) apart, representing the distance through Earth's atmosphere that a transmission from orbit would have to penetrate, says Frank Little, associate director of the CSP.Many other technologies relevant to SBSP have made "enormous progress" in recent years, says John Mankins, who led the Hawaiian island test as chief operating officer and co-founder of Ashburn, Va.–based Managed Energy Technologies, LLC. A little over a decade ago, the best photovoltaic efficiency, or sunlight conversion into electricity, was 10 percent, Mankins says; now it can reach 40 percent. And satellite technology has also improved: Autonomous computer systems as well as advanced, lightweight building materials have also made leaps and bounds, he says.Despite such progress, and spending some $80 million, SBSP has not gotten past the U.S. government's drawing board so far. A key reason, Little says: NASA does not do energy, and the U.S. Department of Energy (DoE) does not do space.The U.S. Department of Defense, however, has recently shown interest in SBSP. Air Force Colonel M. V. "Coyote" Smith cites high fuel costs, along with risks to personnel when supplying petroleum to U.S. combat theaters and bases. A 2007 Defense report (pdf) from the Pentagon's National Security Space Office (NSSO), viewed the commercial development of SBSP quite favorably, especially as traditional, fossil fuel energy sources get ever scarcer in the years ahead. "We've got to identify sources of safe, clean energy in order to help us prevent energy wars in the future," says Smith, one of the authors of the 2007 report.The NSSO report said it would be in the fed's interest to encourage the commercial development of SBSP, but that the government should not design or operate the eventual orbiting power plants.The previous government work, including a joint NASA and DoE report from the 1970s about SBSP, has left its mark on many current architectural schemes, though. This textbook approach calls for a massive, microwave-beaming satellite several miles wide that would sport multiple enormous solar arrays connected to a central hub [like the artist's conception on the first page of the article]. The craft would be perched in orbit about 22,400 miles (36,050 kilometers) above Earth, or a tenth the distance to the moon. There, the satellite would maintain a geostationary, or fixed, position relative to a point on Earth's surface while its solar panel arrays bask in the constant sunlight.Captured solar energy then gets converted on board the satellite into electromagnetic carrier waves, specifically microwaves, ideally at a frequency of either 2.45 or 5.8 gigahertz (both fall on the spectrum between infrared and FM/AM radio signals) for subsequent beaming back to the ground. At that frequency, the waves pass easily through the atmosphere, although some energy—physicists do not know exactly how much yet—would be lost during the transfer, Smith says.This invisible column of microwave energy, measuring perhaps a mile or two (two to three kilometers) across, would be beamed at an oval-shaped, ground-based rectifying antenna, or a "rectenna," of similar size, and from there the energy would flow into the traditional electrical grid.Despite the clear analogy to a science fiction death ray, scientists believe the diffuse energy beam from above would not pose a health threat to people or wildlife, even at its most intense center."Microwave radiation is nonionizing, just like visible light or radio signals," says Jim Logan, former chief of medical operations at NASA's Johnson Space Center and an expert on aerospace medicine. That means it lacks sufficient energy, like x-rays and gamma rays, to remove an electron from an atom or a molecule to make a charged particle that can damage DNA and biomolecules, he says.Birds passing through the heart of the carrier wave from space might feel some warmth, Logan wrote in a February white paper on SBSP safety for Space Energy, but not at elevated levels. And should the beam stray from its rectenna target, it would be designed to defocus, Logan says, and not "run amok all over the landscape." Sage of Space Energy says: "We won't be frying birds or turning clouds to steam."Space Energy's first operational array, which adheres to the typical SBSP setup just described, would be designed to generate one gigawatt almost continuously, about the same output as a large nuclear plant. Pursuant to a successful prototype experiment in several years, Space Energy expects that investors would pony up the billions estimated to make a full-scale commercial plant a reality.Building segments of the plant's solar arrays on Earth, along with supports and a central transmitter, would take two years or so, says Stephan Tennsel, CEO and co-founder of Space Energy. Some 40 to 60 launches would boost all the components for the first SBSP satellite into a low Earth orbit (LEO) where a combination of automatic panel unfurling ("like an umbrella," Tennsel says) and robots would assemble and integrate them.Dangers and engineering challenges abound, however: Space junk like that which recently threatened the International Space Station, for example, could collide with the skeletal space solar satellite during assembly. And keeping the satellite's huge beam and the distant rectenna reliably synced up also stands as an unsolved technical issue, says CSP's Little.Overall, the how may be much easier to overcome than the how much. "Technically, we're a lot closer to space-based solar power than we are economically," Little says. The biggest obstacle, he says, continues to be launch costs. "Large structures in space are not showstoppers, but the cost of getting up into space is the real hang-up [for SBSP]," CSP's Best says. In Space Energy's business plan, for instance, half of the $250 million allotted for their communication satellite–size prototype goes toward just lofting the approximately 1,760-pound (800-kilogram) craft into orbit.Though Solaren is tight-lipped about what its pilot power plant will look like, a 2005 patent retained by the company indicates that the firm intends to use mirrors—another oft-explored SBSP element—to gather and focus sunlight prior to converting it to microwaves. According to the patent, Solaren also looks to eliminate many of the structural connectors on its craft—that is, some or all of the satellite's components, including the mirrors, power module and microwave emitter could be "free-floating" in space, orbiting in tandem. "The big thing is to get the weight down so the weight costs don't kill you," says Solaren's Boerman.Backers of SBSP hope that the rising commercialization of space—sparked by the allure of space tourism and the economics of cheaper access—will bring down the expense of rocketing into orbit. Some of the best-known entrepreneurial ventures include Richard Branson's Virgin Galactic and Elon Musk's SpaceX, but almost 20 companies are trying their hand at lowering launch overhead. "These organizations could potentially change the picture of launch costs," Best says.Many other obstacles stand in the way of commercially viable SBSP. A crucial regulatory matter: getting clearance from the U.N.'s International Telecommunication Union (ITU) that allocates use of the electromagnetic spectrum. SBSP's ideal microwave frequencies are already used by wireless systems such as Bluetooth, according to Smith. "Even if we could narrow the beam [from space] down and ensure complete signal integrity in the broadcast wave area," the ITU may deem the possible interference from SBSP as too disruptive to some extant technologies, he says.Some think that SBSP efforts should zero in on lasers rather than microwave transmission to avoid this and other confounding issues. "I think an approach using microwaves is doomed," N.Y.U.'s Hoffert says. Given the necessary size of microwave transmitters and their solar arrays, "it's a huge capital investment before you get one kilowatt of power," he adds.A higher efficiency, laser-based approach would require far smaller satellites and transmitters, perhaps requiring just one launch, Hoffert notes. One proposal involves capturing sunlight in space via photovoltaics, converting the energy into a visible or an infrared laser and then beaming this concentrated light onto existing solar panel arrays in the desert around the clock. Weather can disrupt laser transmissions, however, and Hoffert says other technical hurdles remain for both microwave and laser light approaches.The Japan Aerospace Exploration Agency (JAXA) is covering all bases as Scientific American magazine reported last year. JAXA hopes to have a one-gigawatt satellite in geostationary orbit around 2030 that may use either microwaves or lasers to send its energy back home.Yet another school of thought involves placing solar-power generators and microwave transmitters on the surface of the moon, or even using a lunar base to construct the satellites before launching them (with relative ease, due to moon's far weaker gravity) into a geostationary orbit. Many of the raw materials for crafting the satellites could be mined from the moon as well.If these and other far-flung, future missions ever come to pass, their creators may look back on PG&E's faith this week in Solaren as a key moment in the history of SBSP development, Logan predicts. "If [Solaren] is able to deliver this energy, you're talking about the first time space-based resources have ever been imported to Earth," he says. "It's a significant breakthrough in the awareness of the fact that we're not limited to just the resources on the planet."Auspiciousness aside, Solaren has a long road ahead of it in terms of raising capital and constructing the first-of-its-kind SBSP operation. Soothing local fears of death rays from space will also take some finessing, Logan admits.In the end, PG&E has not invested its customers' or shareholders' finances in the deal, says Marshall, the company spokesperson; rather, Solaren is on the hook to deliver the power first. Over 15 years, Solaren has agreed to provide 200 megawatts of electricity almost continuously, enough for a quarter million homes, starting in June 2016. "Even though PG&E took pains to assure the public they were not investing and that it was only a supply contract, it is still a big step," says CSP's Little. "If another energy supply contract is signed in the near future, I expect interest in space solar will really accelerate."