Harvesting Solar Power from Space

Artist's concept of a space-based solar array. Credit NASA/SAIC

In a new report, the viability of sending solar panels into space to collect a vast quantity of uninterrupted energy has been re-investigated. Although the idea has been around since the 1970’s, space solar power has always been viewed as prohibitively expensive. In the current energy climate down here on Earth with spiralling oil prices and a massive push toward green energy sources, sending massive solar arrays into geosynchronous orbit doesn’t seem like such a strange (or expensive) idea. There are many obstacles in the way of this plan, but the international community is becoming more interested, and whoever is first to set up an orbital array will have a flexible and unlimited energy resource…

It sounds like the perfect plan: build a vast array of solar panels in space. This avoids many of the practical problems we have when building them on Earth such as land availability, poor light conditions and night time, but sending a sunlight farm into space will be expensive to set up. In the 1970’s a plan was drawn up by NASA for the possibility of orbital sunlight “harvesting”, but it was deemed too expensive with a hefty price tag of at least $1 trillion. There was no country in the world that could commit to such a plan. But as we slowly approach an era of cheaper space travel, this cost has been slashed, and the orbital solar energy case file has been re-opened. Surprisingly, it isn’t the most developed nations in the world that are pushing for this ultimate renewable energy source. India and China, with their ballooning populations are reaching a critical point for energy consumption and they are beginning to realise their energy crisis may be answered by pushing into space.

A single kilometer-wide band of geosynchronous Earth orbit experiences enough solar flux in one year to nearly equal the amount of energy contained within all known recoverable conventional oil reserves on Earth today.” – Pentagon’s National Security Space Office 2007 report.

So how could this plan work? Construction will clearly be the biggest expense, but the nation who leads the way in solar power satellites will bolster their economy for decades through energy trading. The energy collected by highly efficient solar panels could be beamed down to Earth (although it is not clear from the source what technology will go into “beaming” energy to Earth) where it is fed into the national grid of the country maintaining the system. Ground based receivers would distribute gigawatts of energy from the uninterrupted orbital supply. This will have obvious implications for the future high demand for electricity in the huge nations in Asia and will wean the international community off carbon-rich non-renewable resources such as oil and coal. There is also the benefit of the flexible nature of this system being able to supply emergency energy to disaster (and war-) zones.

It will take a great deal of effort, a great deal of thought and unfortunately a great deal of money, but it is certainly possible.” – Jeff Keuter, president of the George C. Marshall Institute, a Washington-based research organization.

The most optimistic time frame for a fully operational space-based sunlight collection satellite would be 2020, but that is if we started work now. Indeed some research is being done (Japan is investing millions of dollars into a potential prototype to be put into space in the near future), but this is a far cry from planning to get full-scale operations underway in a little over a decade…

Source: CNN International

It Really Looks Like Ice on Mars

Take a look at this image sent back from the Phoenix lander. On Friday, Phoenix scientist Ray Arvidson said there may be ice directly under the Phoenix lander, exposed in the blast zone by the retrorockets used for Phoenix’s soft landing. Friday’s image showed a small portion of the exposed area that looks brighter and smoother than the surrounding soil. On Saturday, Sol 5 for Phoenix on Mars, a new image shows a greater portion of the area under the lander. Scientists say the abundance of excavated smooth and level surfaces adds evidence to a hypothesis that the underlying material is an ice table covered by a thin blanket of soil. This is just what the Phoenix mission was hoping to find, and how incredible to land directly over your goal.

The bright-looking surface material in the center, where the image is partly overexposed, may not be inherently brighter than the foreground material in shadow. But the scientists are calling this area “Holy Cow.” Reportedly (via Emily at the Planetary Society) that’s exactly the phrase exclaimed when this image was returned. More pictures of this feature will be imaged using different exposures in an effort to determine if this really is ice.

The other interesting aspect of this image is that the retrorocket nozzles are visible right at the top of the image.

We’ll keep you posted when there’s more information and data available on the area under the lander.

Sources: Phoenix, Planetary Blog

Warm Coronal Loops May Hold the Key to Hot Solar Atmosphere

Coronal loops as imaged by TRACE at 171 Angstroms (1 million deg C) (NASA/TRACE)

Coronal loops, the elegant and bright structures threading through the solar surface and into the solar atmosphere, are key to understanding why the corona is so hot. Yes, it’s the Sun, and yes, it’s hot, but its atmosphere is too hot. The puzzle as to why the solar corona is hotter than the Sun’s photosphere has kept solar physicists busy since the mid-twentieth century, but with the help of modern observatories and advanced theoretical models, we now have a pretty good idea what is causing this. So is the problem solved? Not quite…

So why are solar physicists so interested in the solar corona anyway? To answer this, I’ll pull up an excerpt from my first ever Universe Today article:

measurements of coronal particles tell us the atmosphere of the Sun is actually hotter than the Suns surface. Traditional thinking would suggest that this is wrong; all sorts of physical laws would be violated. The air around a light bulb isn’t hotter than the bulb itself, the heat from an object will decrease the further away you measure the temperature (obvious really). If you’re cold, you don’t move away from the fire, you get closer to it! – from “Hinode Discovers Sun’s Hidden Sparkle“, Universe Today, December 21st, 2007

This isn’t only an academic curiosity. Space weather originates from the lower solar corona; understanding the mechanisms behind coronal heating has wide-ranging implications for predicting energetic (and damaging) solar flares and forecasting interplanetary conditions.

So, the coronal heating problem is an interesting issue and solar physicists are hot on the trail of the answer to why the corona is so hot. Magnetic coronal loops are central to this phenomenon; they are at the base of the solar atmosphere and experience rapid heating with a temperature gradient from tens of thousands of Kelvin (in the chromosphere) to tens of millions of Kelvin (in the corona) over a very short distance. The temperature gradient acts across a thin transition region (TR), which varies in thickness, but can be only a few hundreds of kilometers thick in places.

These bright loops of hot solar plasma may be easy to see, but there are many discrepancies between the observation of the corona and coronal theory. The mechanism(s) responsible for heating the loops have proven to be hard to pin down, particularly when trying to understand the dynamics of “intermediate temperature” (a.k.a. “warm”) coronal loops with plasma heated to around one million Kelvin. We are getting closer to solving this puzzle which will aid space weather predictions from the Sun to the Earth, but we need to work out why the theory is not the same as what we are seeing.

The Sun in EUV. A comparison between solar minimum (left) and maximum (right). Coronal loops are most active at solar max (SOHO/NASA)

Solar physicists have been divided on this topic for some time. Is coronal loop plasma heated by intermittent magnetic reconnection events throughout the length of a coronal loop? Or are they heated by some other steady heating very low in the corona? Or is it a bit of both?

I actually spent four years wrestling with this issue whilst working with the Solar Group at the University of Wales, Aberystwyth, but I was on the side of “steady heating”. There are several possibilities when considering the mechanisms behind steady coronal heating, my particular area of study was Alfvén wave production and wave-particle interactions (shameless self-promotion… my 2006 thesis: Quiescent Coronal Loops Heated By Turbulence, just in case you have a spare, dull weekend ahead of you).

James Klimchuk from the Goddard Space Flight Center’s Solar Physics Laboratory in Greenbelt, Md., takes a different opinion and favours the nanoflare, impulsive heating mechanism, but he is highly aware that other factors may come into play:

It has become clear in recent years that coronal heating is a highly dynamic process, but inconsistencies between observations and theoretical models have been a major source of heartburn. We have now discovered two possible solutions to this dilemma: energy is released impulsively with the right mix of particle acceleration and direct heating, or energy is released gradually very close to the solar surface.” – James Klimchuk

The Hinode solar observatory, measures the Sun in X-ray and EUV wavelengths (JAXA)

Nanoflares are predicted to maintain warm coronal loops at their fairly steady 1 million Kelvin. We know the loops are this temperature as they emit radiation in the extreme ultraviolet (EUV) wavelengths, and a host of observatories have been built or sent into space with instruments sensitive to this wavelength. Space-based instruments such as the EUV Imaging Telescope (EIT; onboard the NASA/ESA Solar and Heliospheric Observatory), NASA’s Transition Region and Coronal Explorer (TRACE), and the recently operational Japanese Hinode mission have all had their successes, but many coronal loop breakthroughs occurred after the launch of TRACE back in 1998. Nanoflares are very hard to observe directly as they occur over spatial scales so small, they cannot be resolved by the current instrumentation. However, we are close, and there is a trail of coronal evidence pointing to these energetic events.

Nanoflares can release their energy in different ways, including the acceleration of particles, and we now understand that the right mix of particle acceleration and direct heating is one way to explain the observations.” – Klimchuk.

Slowly but surely, theoretical models and observation are coming together, and it seems that after 60 years of trying, solar physicists are close to understanding the heating mechanisms behind the corona. By looking at how nanoflares and other heating mechanisms may influence each other, it is very likely that more than one coronal heating mechanism is at play…

Aside: Out of interest, nanoflares will occur at any altitude along the coronal loop. Although they may be called nanoflares, by Earth standards, they are huge explosions. Nanoflares release an energy of 1024-1026 erg (that is 1017-1019 Joules). This is the equivalent of approximately 1,600 to 160,000 Hiroshima-sized atomic bombs (with the explosive energy of 15 kilotonnes), so there is nothing nano about these coronal explosions! But on the comparison with the standard X-ray flares the Sun generates from time to time with a total energy of 6×1025 Joules (over 100 billion atomic bombs), you can see how nanoflares get their name…

Original source: NASA

Phoenix Spies Possible Ice; TEGA Short Circuit Likely

Scientists from the Phoenix mission say the lander may have exposed ice just beneath Mars surface when soil was blown away as the spacecraft landed last Sunday, May 25. The possible ice appears in an image the robotic arm camera took underneath the lander, near a footpad. The robotic arm was moved so the camera could peer beneath the lander to make sure Phoenix’s footing is secure before any digging operations start. In the top center of the image above is the area in question.


“We could very well be seeing rock, or we could be seeing exposed ice in the retrorocket blast zone,” said Ray Arvidson of Washington University, St. Louis, Mo., co-investigator for the robotic arm. “We’ll test the two ideas by getting more data, including color data, from the robotic arm camera. We think that if the hard features are ice, they will become brighter because atmospheric water vapor will collect as new frost on the ice.”

Arvidson said in today’s Phoenix press conference that Phoenix will provide full confirmation of what lies below the lander when it excavates and analyzes layers in the nearby landscape.

One bad piece of news for the nearly flawless mission, however. The Thermal and Evolved Gas Analyzer (TEGA) instrument that “bakes and sniffs” samples to identify the chemical make-up of the soil might have a short circuit. In a test conducted on Thursday, the instrument exhibited electrical behavior consistent with an intermittent short circuit in the spectrometer portion. The team is currently developing diagnostic steps that will be sent to the lander in the next few days. TEGA includes a calorimeter that tracks how much heat is needed to melt or vaporize substances in a sample, plus a mass spectrometer to examine vapors driven off by the heat.

“We have developed a strategy to gain a better understanding of this behavior, and we have identified workarounds for some of the possibilities,” said William Boynton of the University of Arizona, Tucson, lead scientist for the instrument.

The latest data from the Canadian Space Agency’s weather station shows another sunny day at the Phoenix landing site with temperatures holding at minus 30 degrees Celsius (minus 22 degrees Fahrenheit) as the sol’s high, and a low of minus 80 degrees Celsius (minus 112 degrees Fahrenheit). The LIDAR instrument was activated for a 15-minute period just before noon local Mars time, and showed increasing dust in the atmosphere.

If you’d like to download this Phoenix weather widget for your desktop, check HERE.

“This is the first time LIDAR technology has been used on the surface of another planet,” said the meteorological station’s chief engineer, Mike Daly, from MDA in Brampton, Canada. “The team is elated that we are getting such interesting data about the dust dynamics in the atmosphere.” HERE is an animation of the LIDAR

The mission passed a “safe to proceed” review on Thursday evening, meeting criteria to proceed with evaluating and using the science instruments.

“We’re still in the process of checking out our instruments,” Phoenix project scientist Leslie Tamppari of JPL said. “The process is designed to be very flexible, to respond to discoveries and issues that come up every day. We’re in the process of taking images and getting color information that will help us understand soil properties. This will help us understand where best to first touch the soil and then where and how best to dig.”

And finally, here’s the latest version of Phoenix’s panorama, compiled of images from Phoenix’s Stereo Surface Imager (SSI) camera that were taken on sols 1 and 3. The top portion has been stretched eight fold to show details of features in the background. Phoenix’s parachute, backshell, heatshield, and impact site can also be seen.

Lunar Art

NASA recently invited college and high school students to submit artwork for a contest on the theme “Life and Work on the Moon.” NASA encouraged students to form inter-disciplinary teams, so that art and humanities students could collaborate with science and engineering students, “to produce the most well-informed art work possible.” NASA just announced the winners of the contest. The first place submission is above, and is called Traffic Jam, by Justin Burns, a sophomore at the University of Memphis.

Why would an institution like NASA sponsor an art contest? “Once humans establish a presence on the Moon, the arts will be a desired facet of life there, as they are here on Earth,” says NASA’s art contest web page. “It is our intention to provoke non-science and engineering students to think about the science and engineering required to achieve the conditions suitable for humans to live and work on the moon. It is also our intention to help the science and engineering communities appreciate valuable contributions from other communities, particularly the arts.”

See more of the winners below:


2nd Place: “A Busy Day on the Moon” by Johnathan Culpepper, Senior, Medgar Evers College

3rd Place: “Enabling Exploration” by Lann Brumlilk and Corey DiRutigliano, Graduate Students, University of Cincinnati

4th Place: “Perseid Meteor Shower on a Newly Terra-formed Moon” by Ellen Ladwig, Senior, University of Missouri, St. Louis

High School Division: Tie for 1st Place:

“Pole Colony” by Asa Shultz, High School Senior, Home-schooled, Covenant Academy

“To the Moon and Beyond” by William Zhang, High School Sophomore, Skoldberg Art Academy

Source: NASA Art Contest page

Meet Us in St. Louis

I’ll be attending the American Astronomical Society/Astronomy Society of the Pacific Meeting in St. Louis for the next few days, starting Saturday, May 31 with some educational workshops and symposiums, and then Monday-Thursday is the AAS conference. This will be my first conference as a journalist, and I’m looking forward to being overwhelmed and star-struck.

If you’ll be there, or if you happen to be in the St. Louis area, we are planning a “Astroblogger Meet-Up” on Tuesday, June 3 at 7:00 pm at KitchenK bar & restaurant. The big names who will be there: Pamela Gay from Astronomy Cast and Star Stryder, Phil Plait from Bad Astronomy, Chris Lintott from Chris Lintott’s Universe and Galaxy Zoo, and Tammy Plotner and me (Nancy) from Universe Today, and more. Please join us if you can!

If you can’t be in St. Louis, we’ll try to bring the conference to you via reports and articles here on UT and liveblogging on Astronomy Cast Live.

Temperature Conditions of a Supernova Recreated in UK Laboratory

A scientist cleans a vacuum spatial filter for the Vulcan Petawatt Facility during construction (Rutherford Appleton Laboratory)

Scientists are one step closer to attaining the ultimate goal: producing temperatures high enough to sustain fusion, the reaction that powers our Sun and the possible future for global energy production. Researchers at the Rutherford Appleton Laboratory in Oxfordshire, UK, have attained temperatures higher than the surface of the Sun, 10 million Kelvin (or Celsius), by using a powerful one petawatt laser called Vulcan. This experiment goes beyond the quest for fusion power; generating these high temperatures recreates the conditions of cosmological events such as supernova explosions, and astronomical bodies like white dwarfs and neutron star atmospheres…

This is some awesome research. An international collaboration of researchers from the UK, Europe, Japan and the US have succeeded in harnessing an equivalent of 100 times the world energy production into a tiny spot, measuring a fraction of the width of a human hair. That’s a whopping one petawatt of energy (one thousand million million watts, or enough to power ten trillion 100W light bulbs) focused on a volume measuring about 0.000009 metres (9µm) across (I took the value of the diameter of a human hair to be 90µm, as measured by Piezo Technology, in case you were interested). This is a vast improvement on previous tests, where the volume heated measured 20 times smaller than this new experiment. This feat was achieved through the use of Rutherford Appleton’s Vulcan laser.

The petawatt laser was able to attain this vast power by delivering a very short-period pulse onto the target. After all, the planet didn’t experience a black out as the laser was switched on, the laser is able to amplify the amount of power available by focusing on a microscopic volume for a short period of time. Vulcan blasted its target with the one petawatt laser beam for a mere 1 picosecond (one millionth of a millionth of a second). This may seem miniscule, but this microscopic period of time allowed the target material to be heated to the 10 million Kelvin.

These tests not only allow scientists to study what happens when matter is heated to such extremes, it also paves the way to more powerful lasers fusing the nuclei of hydrogen, deuterium and tritium. Self-sustaining nuclear fusion may then be possible, unlocking a gateway into a huge source of energy. It is conceivable that a future fusion reactor will use a powerful, focused laser to start fusion events, allowing the energy produced by each reaction to power the next. This is the basis of self-sustaining nuclear fusion.

This is an exciting development – we now have a new tool with which to study really hot, dense matter” – Prof. Peter Norreys, STFC funded researcher and Vulcan scientist.

The Vulcan has some stiff competition though. In the US, the Texas Petawatt laser broke the record for most powerful laser a few days ago, reaching energies in excess of one petawatt. But plans for a bigger UK laser, the Hiper (High Power laser Energy Research), will be even more powerful and is intended to investigate fusion power.

Source: Telegraph

US Wants to Defend Satellites From Laser Attack

In 2006 the US carried out space laser tests (Starfire Optical Range)

So what do you do if someone fires a powerful laser at your satellite? The optics on the satellite will probably be fried, so you couldn’t see who did it. The US military appears to be concerned that this possibility may become a reality. As the US depends more and more on space for communications, GPS and military applications, the US government has announced the development of a defence method intended to detect a ground-based laser attack on a satellite, and pin point the laser’s location. However, some experts have warned against taking this kind of action as there is little evidence other nations are developing anti-satellite laser technology. Also, it may be defence system but it could push further development of the militarization of space…

Satellites can be a pretty vulnerable technology. As showcased by both China and the US in the last year, satellites are well within the scope for anti-satellite missiles. Although both nations contest that the satellite shoot downs were not intended to demonstrate their military prowess in space, many observers have become concerned about the acceleration of research into space weaponry. Pentagon officials have even voiced their concern that their spy satellites may fall fowl of “illumination” by Chinese ground-based lasers. There is however little evidence that China is pursuing this technology.

Even so, the US Air Force has called on contractors to develop a system that will “sense and attribute” a laser attack. This means the technology must have the ability to sense laser emission aimed at a satellite and attribute it to a location on the surface. This development program has become known as Self Awareness/Space Situation Awareness (SASSA). The SASSA system will need to be sensitive to a wide range of laser and radio wavelengths, but the tough part will be to accurately pin-point where the laser is being fired from.

This month, both Lockheed Martin and Boeing have presented their proposals for the SASSA system and the Air Force hopes to fly the winning bid on board an experimental satellite (TacSat-5) in 2011.

Although this is a defensive measure, military analysts are worried that the SASSA could increase tensions around the use of space weapons. As Rob Hewson, analyst and editor for Jane’s Air Launched Weapons, points out, “It’s a defensive step but one that assumes an attack, it is a baby step in the preparation for fighting in space.”

Source: New Scientist Tech

Phoenix News & Weather; Full Panorama Complete, Arm “Raring To Go”

Phoenix’s Surface Stereo Imager (SSI) has finished its initial survey of the area surrounding the Phoenix lander, and returned the images to Earth for completion of the first panorama, seen above. “The panorama takes your around the entire scene,” said Phoenix Principal Investigator Peter Smith. “We see this “hummocky” terrain, with troughs in between the hummocks. In the background we can see the backshell and parachute.” Also visible are disturbances in the soil caused by the landing. And one of the most important aspects of the image shows the robotic arm now up and off the lander, with its scoop in the ready position. Flight Software Lead Matt Robinson reported, “The arm is busted loose now and is raring to go!”

Robinson said the arm is now unstowed out of all its launch restraints, and it required movement from all four of the joints to break loose of the bio-barrier that covered the arm during its journey from Earth. However, it will probably be next week before any digging is done with the arm. The team will first need to determine the stability of the lander. The camera on the end of the arm will look up under the lander to make sure everything is stable, and that each footpad is secure.


Smith said the rocks in the area are fist size, and there are ample places between the rocks to dig down to look for the ice layer thought to lie beneath the Martian surface. Data from the Odyssey spacecraft has indicated water in the form of ice lies beneath the Mars arctic region. Smith added that smaller rocks can be moved by robotic arm, if necessary, to get a good place to dig.

As customary, the science team has begun naming the rocks in the area to help distinguish them, and are using themes from fairy tale characters from Humpty Dumpty, The Legend of sleepy hollow, and Alice in Wonderland.


The “scoop” on the end of Phoenix’s robotic arm is now up and off the lander.

Science team is looking at the patterns in the rocks, and patterns in how they are distributed around the hummocks and troughs. “We do not have a full spectral analysis of any of the rocks, so its early to say anything about their composition,” Smith said. “That’s high on our list of things to do.” He added that the 12 spectroscopic filters on the SSI should be able to tell us if they are the same as the five other locations we’ve studied on Mars. He also offered a couple of clues about the rocks: Many are flat like paving stones, which may be a clue to their origin, and the rocks seem to be brighter than the surface rather than darker.

The SSI can also be used to create stereoscopic images that allow them to get elevation information. Additionally, the camera on the end of the arm, while not stereoscopic, can take one image and then be moved slightly to create stereoscopic images. The suite of science instruments on the arm also includes a microscopic imager with resolution 6 times better than the MER instruments.

Asked how he thought the mission has been going so far, Phoenix project manager Barry Goldstein said, “We’ve exceeded even our optimistic goals.”

And now, here’s the latest weather report from the Phoenix landing site:

Quicktime hi-res movie of the terrain to the northwest of the Phoenix lander.

Link for Mars Weather Widget — Get Mars Weather on your desktop!
Image sources: Phoenix Gallery

Japanese Special Brew: Space Beer

In 1985, Coke was flown into space. The carbon dioxide fizzed all the way through the zero-G blob (NASA)

Well, the title is a little misleading. It should read something like, “Japanese Scientists Brew Beer from Barley that Spent Five Months on the International Space Station,” but that seemed a little too long. It’s not actually beer brewed in space, more beer made from ingredients grown on the ISS. Regardless, the idea is pretty cool. A Japanese company wants to produce 100 bottles of space beer, but commercializing the product may not be a reality quite yet. Even if you might not be able to buy space beer at your local pub, there might not be much different from the normal stuff anyway. But it is a step in the right direction toward the first bar on the Moon or Mars…

The Japanese, known for their traditional alcoholic tipple Saké, are about to become known for their space beer brewing exploits too. Using third-generation barley grown on the ISS for 5 months in 2006, the brewing company Sapporo is hoping to roll out their first 100 bottles of “Space Beer” by this November. The company has been working with Okayama University biologist Manabu Sugimoto and the Russian space agency on producing edible products grown in orbit. This is all in the effort to aid the science behind growing sustainable produce in space for future long-term missions, greatly benefiting future manned settlement plans on the Moon, and eventually Mars.

In the future, we may reach a point where humans will spend an extended period of time in space and must grow food to sustain ourselves […] In the long run, we hope our space research will be not just about producing food, but about enjoying food and relaxing [in space].” – Manabu Sugimoto.

Sapporo Classic Beer (Toby Oxborrow)

On analysing the DNA of barley grown in space and comparing it with barley grown here on Earth, there appears to be no difference between the strains. These results will be presented in July at a conference in Canada with a focus on the cultivation of plants in a space environment. Barley is a hardy plant, allowing it to grow in challenging environments in a range of temperatures. It is also high in fibre and nutrients, essential for the health of astronauts and future space colonists. Making beer from barley grown in space may seem pretty inconsequential, but once this is achieved, more products familiar here on Earth may be grown and manufactured in space.

As for brewing beer in a zero-G environment, this may be many years off. In separate experiments held by NASA in the 1980’s on carbonated drinks, it was found that the “fizz” cannot rise in the liquid (as there is no gravity, pictured top). The foam you’d associate with the head on a pint of beer would be non-existent in zero-G as the bubbles become suspended within the liquid. This has the unappealing effect of producing “wet burps” when drunk by astronauts – the liquid does not become separated from the gas, expelling the gas by belching also expels some liquid. This is one of the main reasons why carbonated drinks are not on the ISS menu.

For now, space beer, drunk in space, will probably be confined to consumption on planets, where gravity will help alleviate any messy burps…

Sources: Physorg.com, New Scientist