Satellites on a Budget – High Altitude Balloons

Balloon photograph taken from 25km. Image credit: Paul Verhage. Click to enlarge.
Paul Verhage has some pictures that you’d swear were taken from space. And they were. But Verhage is not an astronaut, nor does he work for NASA or any company that has satellites orbiting Earth. He is a teacher in the Boise, Idaho school district. His hobby, however, is out of this world.

Verhage is one of about 200 people across the United States who launch and recover what have been called a “poor man’s satellite.” Amateur Radio High Altitude Ballooning (ARHAB) allows individuals to launch functioning satellites to “near space,” at a fraction of the cost of traditional rocket launch vehicles.

Usually, the cost to launch anything into space on regular rockets is quite high, reaching thousands of dollars per pound. Additionally, the waiting period for payloads to be put on a manifest and then launched can be several years.

Verhage says that the total cost for building, launching and recovering these Near Spacecraft is less than $1,000. “Our launch vehicles and fuel are latex weather balloons and helium,” he said.

Plus, once an individual or small group begins designing a Near Spacecraft, it could be ready for launch within six to twelve months.

Verhage has launched about 50 balloons since 1996. Payloads on his Near Spacecraft include mini-weather stations, Geiger counters and cameras.

Near space lies begins between 60,000 and 75,000 feet (~ 18 to 23 km) and continues to 62.5 miles (100km), where space begins.

“At these altitudes, air pressure is only 1% of that at ground level, and air temperatures are approximately -60 degrees F,” he said. “These conditions are closer to the surface of Mars than to the surface of Earth.”

Verhage also said that because of the low air pressure, the air is too thin to refract or scatter sunlight. Therefore, the sky is black rather than blue. So, what is seen at these altitudes is very close to what the shuttle astronauts see from orbit.

Verhage said his highest flight reached an altitude of 114,600 feet (35 km), and his lowest went only 8 feet (2.4 meters) off the ground.

The main parts of a Near Spacecraft are flight computers, an airframe, and a recovery system. All these components are reusable for multiple flights. “Think of building this Near Spacecraft as building your own reusable Space Shuttle,” said Verhage.

The avionics operates experiments, collects data, and determines the status of the spacecraft, and Verhage makes his own flight computers. The airframe is usually the most inexpensive part of the spacecraft and can be made from materials such as Styrofoam and Ripstop Nylon, put together with hot glue.

The recovery system consists of a GPS, a radio receiver such as a ham radio, and a laptop with GPS software. Additionally, and probably most important is the Chase Crew. “It’s like a road rally,” says Verhage, “but no one in the Chase Crew knows quite for sure where they are going to end up!”

The process of launching a Near Spacecraft involves getting the capsule ready, filling the balloon with helium and releasing it. Ascent rates for the balloons vary for each flight but are typically between 1000 and 1200 feet per minute, with the flights taking 2-3 hours to reach apogee. A filled balloon is about 7 feet tall and 6 feet wide. They expand in size as the balloon ascends, and at maximum altitude can be over 20 feet wide.

The flight ends when the balloon bursts from the reduced atmospheric pressure. To ensure a good landing, a parachute is pre-deployed before launch. A Near Spacecraft will free fall, with speeds of over 6,000 feet per minute until about 50,000 feet in altitude, where the air is dense enough to slow the capsule.

The GPS receiver that Verhage uses signals its position every 60 seconds, so after the spacecraft lands, Verhage and his team usually know where the spacecraft is, but recovering it is mostly a matter of being able to get to where it lies. Verhage has lost only one capsule. The batteries died during the flight, so the GPS wasn’t functioning. Another capsule was recovered 815 days after launch, found by the Air National Guard near a bombing range.

Some balloons are recovered only 10 miles from the launch site, while others have traveled over 150 miles away.

“Some of the recoveries are easy,” said Verhage. “In one flight, one of my chase crew, Dan Miller, caught the balloon as it landed. But some recoveries in Idaho are tough. We’ve spent hours climbing a mountain in some cases.”

Other experiments that Verhage has flown include a Visible Light Photometer, Medium Bandwidth Photometers, an Infrared Radiometer, a Glider Drop, Insect Survival, and Bacteria Exposure.

One of Verhage’s most interesting experiments involved using a Geiger counter to measure cosmic radiation. On the ground, a Geiger counter detects about 4 cosmic rays a minute. At 62,000 the count goes to 800 counts per minute, but Verhage discovered that above that altitude the count does down. “I learned about primary cosmic rays from that discovery,” he said.

Flying the experiments are a great experience, Verhage said, but launching a camera and getting pictures from Near Space provides an irreplaceable “wow” factor. “To have an image of the Earth showing its curvature is pretty amazing,” Verhage said.

“For cameras,” he continued, “the dumber they are the better. Too many of the newer cameras have a power save feature, so they shut off when they’re not used in so many minutes. When they turn off at 50,000 feet, there’s nothing I can do to turn them back on.”

While digital cameras are easy to interface with the flight computer, Verhage said, they require some inventive wiring too keep the camera from shutting off. He said that so far, his best photos have come from film cameras.

Verhage is writing an e-book that details how to build, launch and recover a Near Spacecraft, and the first 8 chapters are available free, online. The e-book will have 15 chapters when finished, totaling about 800 pages in length.
Parallax, the company that manufactures a microcontroller is sponsoring the e-book’s publication.

Verhage teaches electronics at the Dehryl A. Dennis Professional Technical Center in Boise. He writes a bimonthly column about his adventures with ARHAB for Nuts and Volts magazine, and also shares his enthusiasm for space exploration through the NASA/JPL Solar System Ambassador program.

Verhage said his hobby incorporates everything he is interested in: GPS, microcontrollers and space exploration, and he encourages anyone to experience the thrill of sending a spacecraft to Near Space.

By Nancy Atkinson

Bringing Stardust Home

Stardust’s sample return capsule, safely back on Earth. Image credit: NASA/JPL. Click to enlarge.
NASA’s Stardust spacecraft is now back home, having traveled 4.6 billion kilometers (3 billion miles) and successfully completed its mission in space. On January 15, Stardust’s Sample Return Capsule (SRC) landed safely in the Utah desert, containing samples of a comet’s coma and interstellar dust particles. Stardust was launched in 1999, and in January 2004, the spacecraft performed a risky and historic flyby of Comet Wild 2 to capture the samples and take pictures of the comet’s nucleus.

The trickiest part of the mission, however, may have been guiding the spacecraft back home. The Stardust Navigation Team at NASA’s Jet Propulsion Laboratory in California has been working around the clock for the past few weeks, preparing to bring Stardust’s SRC back through Earth’s atmosphere to land in the US Air Force’s Utah Test and Training Range, southwest of Salt Lake City.

For a successful re-entry and landing, the Navigation team had to target the capsule’s entry to a specific point in the Earth’s atmosphere to within eight 100ths of a degree. One mission manager compared that feat to hitting the eye of a sewing needle from across the room.

Throughout the mission the Stardust scientists have heralded the performance of this desk-sized spacecraft. But members of the Navigation Team have maintained that Stardust’s design provided unprecedented navigation challenges during its entire 7- year mission, culminating with the Earth return.

“Navigating this spacecraft has always been extremely difficult because the attitude control thrusters are all mounted on the same side of the spacecraft,” said Neil Mottinger, a member of the Navigation and Entry, Descent and Landing teams.

The thrusters provide gentle pushes that allow a spacecraft to maintain the correct position while in flight. Normally, most spacecraft have their thrusters placed equally around all sides, but Stardust’s thrusters were positioned so the plume of the thrusters wouldn’t contaminate the particle collector.

“This ‘unbalanced’ thruster design causes a velocity change every time the spacecraft needed to control its attitude, which can occur hundreds of times a day,” said Christopher Potts, the Technical Supervisor of the Flight Path Control Group. “Each thruster pulse is extremely small, but the large number adds up to a significant effect on the trajectory.”

Consequently, the Navigation team needed to closely monitor the daily activity of the spacecraft. “It’s a little like trying to catch a knuckleball,” said Potts, “as the spacecraft trajectory changed noticeably as it reacted to its local space environment.”

Mottinger said that in some aspects, the spacecraft was almost like a bucking bronco. “It was impossible to predict when the thrusters would fire during normal spacecraft operations,” he said, “let alone the times when it would go into a safe mode, firing the thrusters quite frequently to obtaining a ‘safe’ attitude, awaiting further instructions from Earth.”

Both Mottinger and Potts said that in the past few weeks, the Navigation team has gone through tests, training and several full rehearsals for the spacecraft’s return. “We spent a large amount of time postulating what could go wrong,” Potts said, “and making sure there was an appropriate response to correct the problem.”

But with the Navigation Team’s diligent guidance, the SRC landed perfectly, much to the delight and relief of everyone involved with Stardust. Stardust Project Manager Thomas Duxbury said at a press conference following the landing, “This thing went like clockwork. We released this capsule from our spacecraft and it hit the atmosphere exactly on time.”

Mottinger said the hard work the team put in was definitely worth the rewards. “This team has to be exhausted,” he said. “It’s been a real challenge to predict where the spacecraft was headed and fine-tune the entry. I’m in awe of everyone on the Navigation Team who made all this happen.”

Stardust’s SRC will be brought to a clean room at the Johnson Space Center in Houston to be opened. Scientists from around the world will be able to study the thousands of particles of cometary and interstellar dust, many smaller than the width of a human hair. The particles were collected from the coma or “tail,” a cloud of gas and dust that surrounds a comet.

Comets are intriguing bodies, formed in the outer regions of the solar system. Scientists consider comets to be the best samples available of the original building blocks of our solar system, and that the particles Stardust returned should be able to tell us about the conditions of the early solar system.

To determine the makeup of the collected particles, scientists will cut the samples into even smaller pieces and investigate them with powerful microscopes. Stardust scientists are recruiting volunteers to search for the interstellar dust particles using virtual microscopes.

The collector is about the size and shape of a tennis racquet, and is made of a unique substance called Aerogel. Aerogel is made of silicon, but is 99.8% air, so it is the least dense man-made substance. It feels like an extremely light, very fine, dry sponge, and it has the ability to capture fast moving dust. It’s very strong, and easily survived the capsule’s landing on solid ground.

Mottinger and Potts both look forward to seeing the results that the study of Stardust’s samples will bring.

“The entire Navigation team realized we were responsible for delivering a ‘priceless’ cargo of pristine cometary material samples from a comet’s coma,” said Potts. “These samples represent a glimpse back in time at the early formation of the solar system. There’s little doubt that new science discoveries will be made which will influence the direction of future space exploration.”

Written by Nancy Atkinson

Leading the Way Back to the Moon

Computer illustration of the CEV in orbit around the Moon. Image credit: NASA. Click to enlarge.
Jeff Hanley was only 8 years old on July 20, 1969 when Apollo 11 landed on the moon, but he can recall every detail of that day and all the specifics of that historic mission. Each of the Apollo missions to the moon made such a big impact on Hanley that space exploration became his life’s passion, ultimately becoming his profession. Now, Hanley has been appointed to lead NASA’s new program to return astronauts to the moon and prepare to send human expeditions to Mars.

Hanley started working at NASA while he was still in college and eventually became a flight controller in Houston’s Mission Control for 13 years, and then became a flight director in 1996. He oversaw two of the complex missions to refurbish the Hubble Space Telescope and was the lead flight director for the first expedition crew to the International Space Station in 2000. He led the Space Station Flight Director Office for two years before being promoted to chief of flight directors for all space missions in January of 2005.

Hanley has served in his current position as manager for NASA’s new Constellation Program since October 2005. His tenure thus far has been a series of constant meetings, briefings and trips around the country to the various NASA centers. His job is to lead the development of a new spacecraft and launch system, the focal point of NASA’s Vision for Space Exploration.

“We have not developed a new crew launch system from scratch since the space shuttle in the late 1970’s,” Hanley said. “That’s a generational gap we have to overcome, so we’re building a bridge from what we have today to what we want in the future.” The space vehicles that Hanley and his team are designing are combinations of the best elements from both the space shuttle and the Apollo spacecraft with significant improvements that come from advances in technology.

The new Crew Exploration Vehicle (CEV), while reminiscent of the Apollo blunt-body capsule, is three times larger with the capacity to carry four astronauts to the moon. It also has the ability to dock with the International Space Station, and the same crew vehicle will eventually carry astronauts to Mars. The separate lunar module will be able to land anywhere on the moon, including the poles, unlike the Apollo spacecraft that could only land near the equator. Initially, crews will stay up to 7 days on the moon’s surface.

“Apollo’s purpose was to send a man to the moon and return him safely to the earth,” Hanley said. “We go a substantial step beyond that with this architecture in terms of the capacity to deliver large amounts of mass to the moon and that’s really sending the signal that we’re serious about exploration and serious about coming to stay.” Developing a sustained presence on the moon will be the ultimate goal of the lunar missions, to demonstrate that humans can survive for long periods of time on another world.

Computer illustration of the CEV in orbit around the Moon. Image credit: NASA. Click to enlarge.
Instead of launching the entire system at once, the CEV and the lunar module launch separately. “In NASA shorthand we call it the 1.5 launch solution,” Hanley said. “The big heavy booster brings the lunar module and the upper stage to orbit and we’ll follow it with the crew launch vehicle, which launches on a smaller rocket, and the two vehicles will rendezvous and dock. Then we’ll light the Earth departure stage and send it on the way to the moon.”

Hanley continued, “We also want a quantum leap in safety and reliability in our launch systems over anything we have today.” Based on an engineering study, the new launch system will be 10 times safer than the space shuttle. The crew compartment sits on top of the rocket, unlike the space shuttle which is strapped to the rocket’s side. This allows for an escape system that can be used at anytime during launch.

The rockets will combine the reliability and power of solid rocket motors and the space shuttle main engines. The crew launch vehicle will be a single four-segment solid rocket motor with one shuttle main engine, which can lift 25 metric tons. The heavy cargo launch system will consist of two five-segment solid rockets and five shuttle main engines, which can boost 106 metric tons to orbit. A cargo-only mission could bring 21 metric tons of supplies to the moon.

Hanley anticipates the new spacecraft will be ready for its first launch in 2012, but he is challenging his team to have the spacecraft ready as soon as possible. “Our ideal is to make as small a gap as possible between the last shuttle flight [scheduled for 2010] and the first human flight of this system,” he said. “If we have things break our way and utilize good management practices in putting this together, I think we can do it.”

Hanley disagrees with the critics of NASA’s new program who say that returning to the moon is a waste of time and resources when the ultimate human destination is Mars, or perhaps other moons or asteroids. “That would be like the first explorers trying to circumnavigate the earth the first time they set out on the ocean,” he said. “That seems a little na?ve to me. The moon is three or four days away with the current rockets we have. Mars is months away. Once you light off the engines on the Mars transfer vehicle, there’s no turning back. You must have incredibly reliable systems to commit to those kinds of journeys.”

Hanley feels the only way to build up robustness and reliability of a spacecraft is through repeated use over time. “You’ve designed them, built them, and flown them over a period of time such that you’ve weeded out the ‘unknown unknowns,’ as we call them,” he said. “The moon gives us a natural platform to learn from when we get to the point when there’s no turning back from going to Mars.”

In addition, Hanley says, the exploration of other planets will only be successful if we learn to live off the land. “If you look in general at the history of exploration,” he said, “it wouldn’t have been possible without being able to live off the land. We have to learn how to use the available assets, like lunar soil and ice and convert that into rocket fuel and air, cultivating a way station, if you will, from which to test out systems for future exploration.”

Hanley believes that the successful international cooperation that has been forged through the International Space Station program should continue and expand through returning to the moon. “One of the unsung successes of the ISS program is the strong international team that has been cultivated,” he said. “The partnership has endured strains and come through them in great shape. The kinds of relationships and understandings we have today are a great basis on which to build more relationships for exploration.”

“Really,” he continued, “we have no choice but to partner with others to create a really robust program. NASA’s budget in the timeframe we are talking about just won’t be big enough to do all the things that possibly could be done, such as building habitats, rovers, and scientific stations. So there’s a huge opportunity for partners to come in and add value, robustness and capabilities.” Hanley said there have already been discussions at high levels with other space agencies on these matters.

The ISS has also been criticized as wasting time and resources, but Hanley feels everything that has been learned through the ISS program is invaluable. “What we eventually want to do at Mars,” he said, “is build an outpost off the planet. The ISS already is an outpost off the planet. We’ve learned an incredible amount in creating it, sustaining it, and it will, by its very nature, inform us of what the best approaches will be to take the next step.”

“Station is helping us to expand our horizons,” Hanley continued. “We’re learning through the engineering of our systems and cultivating our capabilities at that outpost, so we’re learning about how to rely less and less on supplies from the planet. We’re building heritage. And as soon as we learn the lessons we need to learn on the moon, we will be setting our sights on Mars and I don’t think that will be very long into the future.”

Written by Nancy Atkinson

Book Review: Roving Mars

Somewhere in the midst of exhaustive preparation, astounding scientific discoveries, and a constantly shifting schedule in order to stay on Mars’ time, Steve Squyres, the ebullient scientific leader of the Mars Exploration Rover (MER) program, found time to write an intriguing, behind-the-scenes book about his adventures with NASA’s two endearing rovers, Spirit and Opportunity.

Roving Mars: Spirit, Opportunity, and the Exploration of the Red Planet is a highly readable, personal account of the perseverance and sacrifices it takes to fly a NASA planetary mission. Squyres writes with clarity, eloquence and passion, sharing the gamut of emotions he has experienced in heading up a project of this magnitude.

Roving Mars is divided into three sections, with the first two parts providing an in-depth overview of the MER project from its initial formation in the imaginations of Squyres and his colleagues, through the various designs and configurations that the project endured, to the actual development, testing and launch of the two rovers. With the project plagued initially by politics and bad luck, and then with technical problems with the parachute, airbags and essential scientific equipment, Squyres reveals that MER ran the risk of being canceled almost right until launch. The author tells the stories of the scientific team and the engineers at the Jet Propulsion Laboratory whose tireless dedication and cooperation have made the mission possible. “It’s a strange, heady mix,” writes Squyres, “with NASA-style cool under laid by get-it-done passion, and sometimes, a whiff of desperation.”

Part 3, entitled “Flight” is a real-time diary of events after the rovers launched that follows Spirit and Opportunity into their current explorations on Mars. Squyres’ detailed and vivid descriptions allow the reader to re-live the excitement and drama of events such as the landings of the two rovers and Spirit’s almost fatal computer failure, and provide an inside look at what occurred in mission control, and in Squyres’ mind, in those crucial moments.

With the rovers still going strong after more than a year and a half on Mars, Squyres includes his hopes for the rovers’ future as well as the future of human space exploration. “Roving Mars” includes 32 pages of color photos and illustrations. It is an intriguing and comprehensive account of the mission that has captivated the imaginations of millions.

Read more reviews, or purchase a copy online from Amazon.com.

Review by Nancy Atkinson.

New Horizons Prepares to Zoom to Pluto

Artist impression of the New Horizons spacecraft sweeping past Pluto. Image credit: JHUAPL/SwRI. Click to enlarge.

If all goes well, the first mission to the farthest known planet in our Solar System will launch in early 2006, and give us our first detailed views of Pluto, its moon Charon, and the Kuiper Belt Region, while completing NASA’s reconnaissance of all the planets in our Solar System.

“We’re going to a planet that we’ve never been to before,” said Dr. Alan Stern, Principal Investigator for the New Horizons mission to Pluto. “This is like something out of a NASA storybook, like in the 60’s and 70’s with all the new missions that were happening then. But this is exploration for a new century; it’s something bold and different. Being the first mission to the last planet really ‘revs’ me. There’s something special about going to a new frontier, about

Pluto is so far away (5 billion km or 3.1 billion miles when New Horizons reaches it) that no telescope, not even the Hubble Space Telescope, has been able to provide a good image of the planet, and so Pluto is a real mystery world. The existence of Pluto has only been known for 75 years, and the debate continues about its classification as a planet, although most planetary scientists classify it in the new class of planets called Ice Dwarfs. Pluto is a large, ice-rock world, born in the Kuiper Belt area of our solar system. Its moon, Charon, is large enough that some astronomers refer to the two as a binary planet. Pluto undergoes seasonal change and has an elongated and enormous 248-year orbit which causes the planet’s atmosphere to cyclically dissipate and freeze out, but later be replenished when the planet returns closer to the sun.

New Horizons will provide the first close-up look at Pluto and the surrounding region. The grand piano-sized spacecraft will map and analyze the surface of Pluto and Charon, study Pluto’s escaping atmosphere, look for an atmosphere around Charon, and perform similar explorations of one or more Kuiper Belt Objects.

The spacecraft, built at the Johns Hopkins Applied Physics Laboratory, is currently being flight tested at the Goddard Space Flight Center. Dr. Stern has been planning a mission to Pluto for quite some time, surviving through the various on-again, off-again potential missions to the outer solar system.

“I’m feeling very good about the mission,” he said in an interview from his office at the Southwest Research Institute in Boulder, Colorado. “I’ve been working on this project for about 15 years, and the first 10 years we couldn’t even get it out of the starting blocks. Now we’ve not only managed to get it funded, but we have built it and we are really looking forward to flying the mission soon if all continues to go well.”

Of the hurdles remaining to be cleared before launch, one looms rather large. New Horizons’ systems are powered by a Radioisotope Thermoelectric Generator (RTG), where heat released from the decay of radioactive materials is converted into energy. This type of power system is essential for a mission going far from the Sun like New Horizons where solar power is not an option, but it has to be approved by both NASA and the White House. The 45-day public comment period ended in April 2005, so the project now awaits final, official approval. Meanwhile, the New Horizons mission teams prepare for launch.

“We still have a lot of work in front of us,” Stern said. “All this summer we’re testing and checking out the spacecraft and the components, getting all the bugs out, and making sure its launch ready, and flight ready. That will take us through September and in October we hope to bring the spacecraft to the Cape.”

The month-long launch window for New Horizons opens on January 11, 2006.

New Horizons will be the fastest spacecraft ever launched. The launch vehicle combines an Atlas V first stage, a Centaur second stage, and a STAR 48B solid rocket third stage.

“We built the smallest spacecraft we could get away with that has all the things it needs: power, communication, computers, science equipment and redundancy of all systems, and put it on the biggest possible launch vehicle,” said Stern. “That combination is ferocious in terms of the speed we reach in deep space.”

At best speed, the spacecraft will be traveling at 50 km/second (36 miles/second), or the equivalent of Mach 85.

Stern compared the Atlas rocket to other launch vehicles. “The Saturn V took the Apollo astronauts to the moon in 3 days,” he said. “Our rocket will take New Horizons past the moon in 9 hours. It took Cassini 3 years to get to Jupiter, but New Horizons will pass Jupiter in just 13 months.”

Still, it will take 9 years and 5 months to cross our huge Solar System. A gravity assist from Jupiter is essential in maintaining the 2015 arrival date. Not being able to get off the ground early in the launch window would have big consequences later on.

“We launch in January of 2006 and arrive at Pluto in July of 2015, best case scenario,” said Stern. “If we don’t launch early in the launch window, the arrival date slips because Jupiter won’t be in as good a position to give us a good gravity assist.”

New Horizons has 18 days to launch in January 2006 to attain a 2015 arrival. After that, Jupiter’s position moves so that for every 4 or 5 days delay in launch means arriving at Pluto year later. By February 14 the window closes for a 2020 arrival. New Horizons can try to launch again in early 2007, but then the best case arrival year is 2019.

New Horizons will be carrying seven science instruments:

  • Ralph: The main imager with both visible and infrared capabilities that will provide color, composition and thermal maps of Pluto, Charon, and Kuiper Belt Objects.
  • Alice: An ultraviolet spectrometer capable of analyzing Pluto’s atmospheric structure and composition.
  • REX: The Radio Science Experiment that measures atmospheric composition and surface temperature with a passive radiometer. REX also measures the masses of objects New Horizons flies by.
  • LORRI: The Long Range Reconnaissance Imager has a telescopic camera that will map Pluto?s far side and provide geologic data.
  • PEPSSI: The Pluto Energetic Particle Spectrometer Science Investigation that will measure the composition and density of the ions escaping from Pluto’s atmosphere.
  • SWAP: Solar Wind Around Pluto, which will measure the escape rate of Pluto?s atmosphere and determine how the solar wind affects Pluto.
  • SDC: The Student Dust Counter will measure the amount of space dust the spacecraft encounters on the voyage. This instrument was designed and will be operated by students at the University of Colorado in Boulder.

Stern says the first part of the flight will keep the mission teams busy, as they need to check out the entire spacecraft, and execute the Jupiter fly-by at 13 months.

“The middle years will be long and probably — and hopefully — pretty boring,” he said, but will include yearly spacecraft and instrument checkouts, trajectory corrections, instrument calibrations and rehearsals the main mission. During the last three years of the interplanetary cruise mission teams will be writing, testing and uploading the highly detailed command script for the Pluto/Charon encounter, and the mission begins in earnest approximately a year before the spacecraft arrives at Pluto, as it begins to photograph the region.

A mission to Pluto has been a long time coming, and is popular with a wide variety of people. Children seem to have an affinity for the planet with the cartoon character name, while the National Academy of Sciences ranked a mission to Pluto as the highest priority for this decade. In 2002, when it looked as though NASA would have to scrap a mission to Pluto for budgetary reasons, the Planetary Society, among others, lobbied strongly to Congress to keep the mission alive.

Stern said the mission’s website received over a million hits the first month it was active, and the hit rate hasn’t diminished. Stern writes a monthly column on the website, http://pluto.jhuapl.edu , where you can learn more details about the mission and sign-up to have your name sent to Pluto along with the spacecraft.

While Stern is understandably excited about this mission, he says that any chance to explore is a great opportunity.

“Exploration always opens our eyes,” he said. “No one expected to find river valleys on Mars, or a volcano on Io, or rivers on Titan. What do I think we’ll find at Pluto-Charon? I think we’ll find something wonderful, and we expect to be surprised.”

Has Spirit Found Bedrock in Columbia Hills?

In December of 2004, the mission scientists for the Mars Exploration Rover Spirit spied a ridge near the top of Husband Hill, one of the seven Columbia Hills located near the middle of Mars? Gusev Crater. Steve Squyres, Principal Scientific Investigator for the MER Mission, started calling the ridge ?Larry?s Lookout? and the mission team decided to send Spirit to that ridge to determine what it was and use it as a ?perch? to take a panorama of the valley that it overlooked. They knew it would be a challenge given the sand, steep slope, and rocks in the area, but the scientists are now discovering that the arduous climb was well worth it. According to one geologist, what Spirit is finding at Larry?s Lookout could turn out to be one of the highlights of the MER mission.

The ?Larry? of Larry?s Lookout is Dr. Larry Crumpler; field geologist, volcanologist, and Research Curator at the New Mexico Museum of Natural History and Science in Albuquerque, New Mexico. He is also a mission scientist for MER.

Spirit had originally approached and climbed Larry?s Lookout from the rear, and from that perspective the Lookout appeared to be just a knob on the hill.

But then the rover moved around to the side of Larry?s Lookout, and took a picture that caught the immediate attention of Squyres and other mission scientists. The image looks north along the ridge of the Columbia Hills with Spirit sitting on Husband Hill, and the camera pointed at Clark Hill. The hills are strewn with rocks, and in the foreground are two tilting rocks. The big outcrop just behind the rocks is Larry?s Lookout.

Dr. Crumpler explained the image and the questions it provoked: ?From this perspective, we can see that the outcrop has a tilted look. The two boulders in front of the outcrop appear to be orientated in the same direction. And in the hill in the distance to the right you can see layers that appear to be oriented at the same angles. And to the left, there are outcrops that are oriented at exactly the same angle. The overall impression is that there is some sort of organized layering or structure to the hills. Our big question is, is it just something draped over top of the hills, like ash fall draped over it like snow, or is it an indication of the internal arrangement of the bedding planes in the hills? Did the hills originally form by bulging up, and were the beds originally horizontal? Or did some sort of weathering occur? Any of those interpretations are interesting because it says something has happened subsequent to the original formation of the rocks and hills themselves.?

Crumpler said that this is one of the most interesting areas that Spirit has yet encountered, and the first indication of extensive bedrock. ?For the first time we have started to feel hopeful that we can make sense of the Columbia Hills,? he said. ?I think it is going to be a highlight of the mission.?

Crumpler says they are seeing evidence of finely bedded materials in the rocks, with very fine laminations that signify bedded, sediment-like materials. ?This all indicates that we?re not just looking at volcanic rocks or old broken up rocks, but there is some sort of organized layering,? he said. ?We?re going to do a full scale campaign to try to understand all of these things.? Although the MER science team still has a plethora of unanswered questions about this area of the Columbia Hills, from the evidence so far, water is likely to be at least part of the final equation.

Spirit is just about to begin studying the rock outcrop informally dubbed ?Methuselah,? just to the left of the rover tracks in the image. ?Spirit is looking at this outcrop that is dipping to the northwest and looks like it is laminated with bedding planes,? said Crumpler. ?It is a foot-high outcrop with an odd angle that indicates structure or a deposition that took place on a slope.?

Over the weekend of April 23-24, Spirit was ordered to take a panoramic image of the outcrop in order to give the scientists an overview of the overall pattern and layout of the area.

Crumpler noted that there is a considerable age difference between the Columbia Hills and the lava plain that Spirit crossed to reach the Hills. He likened the Hills to a sandstone butte surrounded by fresh, young lava flows, similar to the landscape that is found in the United States? Southwest. ?The Hills are much, much older,? Crumpler said. ?You can actually see the contact between the two where the lava flows sort of lapped up on the edges of the Hills. When you cross that boundary you go from the basalts which show only small amounts of weathering and alteration to the rocks on the Columbia Hills that are totally ?grunged-up? and altered, and basically water-soaked at some time in their history.?

?We?re still trying to figure out what?s going on here,? Crumpler added, ?but the outcrop we are looking at is giving us some good clues.?

Crumpler has had extensive experience in field geology, and said he has spent a lot of his time walking across New Mexico?s lava flows, just as Spirit trekked across the lava flow in Gusev Crater. He?s always had an intense interest in the geologic exploration of other planets and has been involved in some of the mapping programs of Mars, Venus and Io. But he says the MER program is the most exciting mission of which he?s been a part.

?Everyday there has been something different that we hadn?t seen the day before, or some new perspective of the terrain, so I always say that ?today? is the most exciting part of the mission.?

?When you?re in the field,? he continued, ?you keep moving because you?re always curious about what you?re going to find at the next outcrop that will tell you more about what you are trying to figure out. But we are very likely to be here (at Larry?s Lookout) for a long time giving this outcrop our full attention.?

So, it appears Larry?s Lookout will be keeping Spirit and the MER scientists busy for awhile, as they try to unravel the mysteries of the Columbia Hills.

Written by Nancy Atkinson

Testing New Technologies… In Space

NASA’s New Millennium Program (NMP) was conceived as a way to accelerate the use of advanced technologies into operational science missions. “It was recognized that there were significant investments being made by the United States in advanced technologies,” said Dr. Christopher Stevens, the Program Manager for NMP, “and that they had real applications to either reducing the cost or providing new capability for science missions.” However, bringing these technologies into actual science missions in space is a high risk because of the uncertainty that comes with emerging technology. NMP reduces those risks with validating new technology by flying and testing it in space. “We take technologies that are ready to go forward from the laboratory and mature them so they are ready to go to space,” said Stevens, “but the operational missions could be 10 to 20 years in the future.”

There are two types of missions or systems that NMP undertakes. One is an integrated system validation, where the whole flight system is the subject of the investigation. The second type is a subsystem validation mission, where small, stand alone experiments are carried on a space vehicle, but the vehicle is not part of the experiments.

NMP was jointly established in 1995 by NASA’s Office of Space Science and the Office of Earth Science, and in the past, missions were usually separated as being applicable to future Earth science or space science mission needs. NMP is now managed by NASA’s Science Mission Directorate, and focuses on the needs of three science areas: the Earth-Sun System, Solar System Exploration, and the Universe.

The program began with the Deep Space 1 mission in 1998, which was a space science, integrated system validation. DS1’s defining technology was solar electric, or ion, propulsion. “It was known that this technology had a capability to reduce the mass needed for propulsion over conventional chemical propulsion, but nobody wanted to take the risk of flying it untested in space,” said Stevens. DS1 successfully proved the effectiveness of ion propulsion, and now subsequent missions will use this type of propulsion, including the upcoming Dawn mission.

Other successful NMP validations include improvements and cost reduction of LANDSAT-type satellites and the testing of an autonomous science spacecraft which has flight planning software that can be used on rovers as well as orbiting spacecraft to re-plan a robotic mission with no human intervention. Upcoming NMP missions yet to fly include a group of small satellites called nano-sats that will make simultaneous measurements from multiple places in space of Earth’s magnetosphere, and the testing of equipment to be used on the Laser Interferometer Space Antenna (LISA) mission, a joint mission between NASA and the European Space Agency. The only unsuccessful NMP mission to date was Deep Space 2, which was the Mars Microprobes that were part of the ill-fated Mars Polar Lander.

NASA recently announced the newest NMP mission, Space Technology 8, which is a subsystem validation project. It is a collection of four stand alone experiments that will travel to space on a small, low-cost, currently available spacecraft, dubbed a New Millennium carrier. The first experiment on ST8 is called Sail Mast, which is an ultra-light graphite mast. Applications for Sail Mast are spacecraft that require large membrane structures that need to be deployed, such as solar sails, telescope sunshades, large aperture optics, instrument booms, antennas or solar array assemblies. “There are a series of missions that have been identified on the NASA Roadmap for the future that could benefit from this capability,” said Stevens. “This will be a significant step forward in the mass of the structure. We are operating in a ? kg per meter mass range for a 30 or 40 meter boom that can be stowed compactly and has a reasonable stiffness.”

The second experiment is the Ultraflex Next Generation Solar Array System. This is a high power, extremely lightweight solar array. “This could be used for a mission that needs significant power in a lightweight, deployable array, such as for solar electric propulsion, or it could also be used on the surface of planetary bodies,” said Stevens. “We are looking at increasing the specific power of the array to greater than 170 watts per kilogram on an array that has at least 7 kilowatts of power.”

The third experiment is the Environmentally Adaptive Fault Tolerant Computing System. “Here the objective is to use commercial off the shelf processors configured in an architecture that is fault-tolerant to single event upsets caused by radiation,” said Stevens. “We want to show that this is a robust design that can be used in space without having to use radiation-hard parts, because you get a significant increase in processing speed and capability over currently available radiation-hard processors. We want to reduce the costs with high reliability.” This can be used for processing science data on board a spacecraft, and for autonomous control functions.

The final experiment on ST8 is the Miniature Loop Heat Pipe Small Thermal Management System. “What we want to do here is to reduce the thermal constraints on small spacecraft design and manage heat and the need for cooling without expending significant amounts of power,” said Stevens. This system proposes to efficiently manage thermal balance within the spacecraft by taking heat where it is being produced by, for example, electronics, and provide it to other places in the spacecraft that need heat. It has no moving parts and doesn’t require power.

The ST8 mission should be ready for launch in 2008.

In July of 2005 NASA plans to announce the technology providers for the next NMP mission. ST9 will be an integrated system validation mission. There are five different concepts that we are being considered, and all five are regarded as areas of high priority for NASA. They are:

– Solar Sail Flight System Technology
– Aerocapture System Technology for Planetary Missions
– Precision Formation Flying System Technology
– System Technology for Large Space Telescopes
– Terrain-Guided Automatic Landing System for Spacecraft

All five concepts will be studied over the next year. Following the completion of these studies, one of the five concepts will be selected for ST9. Launch time will depend on which concept is selected, but is tentatively in the 2008-2009 time frame.

Stevens has been with NMP since it was formed, and has been program manager for 3 years. He enjoys being able to demonstrate advanced technologies so that they can be incorporated into future missions. “It’s an exciting business, a very high risk business,” he said, “because advanced technology is so uncertain in regards to how long it will take and how much it will cost.” He said that the validation of the autonomous science spacecraft experiment has been especially rewarding. “The current Mars rovers are extremely labor-intensive, but NASA has not been willing to turn over the operation of a spacecraft to a software package, so I think this validation has been a major step.” Stevens said that his office has a technology infusion activity currently going on with the Mars program, looking at using this capability for future missions, like the Mars Science Laboratory rover, scheduled for launch in 2009.

Written by Nancy Atkinson

Mini-Detector Could Find Life on Mars or Anthrax at the Airport

Image credit: ESA
Dr. David Ermer, with his company, Opti-MS Corporation, is currently constructing a miniature Time of Flight Mass Spectrometer that can detect biological signatures at a very high resolution and sensitivity, but yet be small enough to be used for robotic and human applications in space exploration.

Ermer is using an innovative system that he developed at Mississippi State University, and he has received a NASA Small Business Innovation Research (SBIR) award to continue his research to build and test his device.

A mass spectrometer is used to measure molecular weight to determine the structure and elemental composition of a molecule. A high-resolution mass spectrometer can determine masses very precisely, and can be used to detect such things as DNA/RNA fragments, whole proteins and peptides, digested protein fragments, and other biological molecules.

A Time of Flight Mass Spectrometer (TOF-MS) works by measuring the time it takes for ions to travel through a vacuum area of the device known as the flight tube. Time of flight mass spectrometry is based on the fact that for a fixed kinetic energy, the mass and the velocity of the ions are interrelated. “Electric fields are used to give ions a known kinetic energy,” Ermer explained. “If you know the kinetic energy and know the distance the ions travel, and know how long it takes to travel, then you can determine the mass of the ions.”

Ermer’s device uses Matrix Assisted Laser Desorption Ionization, or MALDI, where a laser beam is directed at the sample to be analyzed, and the laser ionizes the molecules which then fly into the flight tube. The time of flight through the tube correlates directly to mass, with lighter molecules having a shorter time of flight than heavier ones.

The analyser and detector of the mass spectrometer are kept in a vacuum to let the ions travel from one end of the instrument to the other without any resistance from colliding with air molecules, which would alter the kinetic energy of the molecule.

A typical sample plate for a TOF-MS can hold between 100-200 samples, and the device can measure the complete mass distribution with one single shot. Therefore, huge amounts of data are created within a very short time interval, with the time of flight for most ions occurring in microseconds.

Ermer’s TOF-MS combines a relatively simple mechanical setup with extremely fast electronic data acquisition, along with the ability to measure very large masses, which is essential in doing biological analysis.

But the most unique aspect of Ermer’s device is its size. The commercial mass spectrometers that are currently available are at least one and a half meters long. That’s a fairly large volume to include on an in-situ scientific vehicle such as the golf car-sized Mars Exploration Rovers or even the larger Mars Science Laboratory Rover scheduled to launch in 2009. Ermer has devised a way to miniaturize a TOF-MS to an amazing 4? inches long. He estimates that his device will have a volume of less than 0.75 liters, a mass of less than 2 kilograms and require less than 5 watts of power.

Ermer used a non-linear optimization technique to create a computer model of a mass spectrometer. There were 13 parameters he input that had to be selected, including the spacing of the different elements in the TOF-MS and the ion acceleration voltages. Using this technique Ermer was able to find some unique solutions for a very short TOF-MS.

“I’m trying to build a Time of Flight Mass Spectrometer that is small enough to actually go in space,” Ermer said. “The main application that NASA is looking at is searching for biological molecules, to find evidence of past life on Mars. They also want to be able to do molecular biology on the space station, although the Mars application has a higher priority. My device should come in under all the requirements that NASA has, as far as the power, size, and weight requirements.”

Ermer also sees potential for his device to be used commercially as well. “What I have is a portable device to measure biological molecules,” he said. “If you were at an airport and found a white powder you’re going to want to know if it is anthrax or chalk dust fairly quickly. So you want a small, fairly cheap, portable device to be able to do that.” In his proposal to NASA, Ermer stated, “The main (commercial) application for miniature TOF-MS is the screening of infectious disease and biological agents. We also believe that the superior performance of our design will allow penetration into the general TOF-MS market.”

Ermer received the $70,000 SBIR award in mid-January, and has already built and tested a larger proof of concept design, which validates the technology that he designed for his TOF-MS. “So far, the tests have gone extremely well,” Ermer said. I have detected molecules up to 13,000 Daltons (Dalton is an alternate name for atomic mass unit, or amu.) The device is operating as designed for masses up to 13,000 Daltons and has mass resolution somewhat better than a full sized device at 13,000 Daltons. We are currently working on detecting mass out to 100,000 Daltons and initial results are promising.”

“Getting the device up and running is probably the biggest hurdle,” Ermer said about the challenges of this project. “A lot of the hard things are done, but the electronics are really difficult. For this device you have to generate high voltage pulses of about 16,000 volts. That was probably the hardest thing we’ve had to do so far.”

The electron multiplier detector is specially designed for miniature time of flight spectrometry by an outside company. Ermer and his own company designed most of the other parts of the device, including the vacuum housing and the laser extractor. Since it’s so small, creating these parts requires very high tolerance machining, which was also done by an outside company.

The NASA SBIR program “provides increased opportunities for small businesses to participate in research and development, to increase employment, and to improve U.S. competitiveness,” according to NASA. Some objectives of the program are to stimulate technological innovation, and to use small businesses to meet federal research and development needs. The program has three phases, with Phase I receiving $70,000 for six months of research to establish feasibility and technical merit. Projects making it to Phase II receive $600,000 for two more years of development, and Phase III provides commercialization of the product.

Ermer is a professor at Mississippi State University. He has been doing research in fields related to mass spectrometry since 1994, and for his PhD thesis at Washington State University, he looked at the energy distributions of ions that are generated in different materials by a laser. For his postdoctoral research at Vanderbilt, he studied the MALDI technique using an Infrared Free Electron Laser. More information about Opti-MS can be found at www.opti-ms.com.

Nancy Atkinson is a freelance writer and NASA Solar System Ambassador. She lives in Illinois.

A Pristine View of the Universe… from the Moon

Image credit: University of Arizona
Over 30 years ago, Dr. Roger Angel came to the University of Arizona, drawn by the favorable conditions for astronomical observing in the Tucson, Arizona area: several telescopes are conveniently nearby, and of course, the weather is wonderfully temperate. But now, Angel proposes to build a telescope in a location somewhat more remote and not quite so balmy: a polar crater on the moon.

Known for his innovations in lightweight telescope mirrors and adaptive optics, Angel now leads a team of scientists from the U.S. and Canada who are exploring the feasibility of building a Deep-Field Infrared Observatory near one of the lunar poles using a Liquid Mirror Telescope (LMT).

This concept is one of 12 proposals that began receiving funding last October from the NASA Institute for Advanced Concepts (NIAC). Each gets $75,000 for six-months of research to make initial studies and identify challenges in development. Projects that make it through the first phase are eligible for as much as $400,000 more over two years.

LMTs are made by spinning a reflective liquid, usually mercury, on a bowl-shaped platform to form a parabolic surface, perfect for astronomical optics. Isaac Newton originally proposed the theory, but the technology to actually create such a device successfully has only recently been developed. Just a handful of LMTs are being used today, including a 6-meter LMT in Vancouver, Canada, and a 3-meter version that NASA uses for its Orbital Debris Observatory in New Mexico.

On Earth, LMTs are limited in size to about 6 meters in diameter because the self-generated wind that comes from spinning the telescope disturbs the surface. Additionally, like other Earth-based telescopes, LMTs are subject to atmospheric absorption and distortion, greatly reducing the range and sensitivity of infrared observing. But the atmosphere-free moon, Angel says, provides the perfect location for this type of telescope while supplying the gravity necessary for the parabolic mirror to form.

The potential of an LMT on the moon is to make a very big telescope. For reference, the Hubble Space Telescope has a 2.4 meter mirror, and the James Webb Space Telescope (JWST) being developed for launch in 2011 will have a 6 meter mirror. The concept for Angel’s NIAC proposal is a 20 meter mirror, but with the research the team has done so far, they are now looking at creating very large mirrors, with 100 meters being the big end option. They are considering smaller LMTs as well. “We obviously can’t go to the moon and make a 100 meter mirror the first thing,” Angel said. “We’re looking at a sequence of scale sizes of 2 meters, 20 meters, and 100 meters, and are looking at what the potential is for each one.” Angel believes the 2 meter telescope could be made without any human presence on the moon, and set up as a robotic telescope, much like the scientific instruments on the Mars rovers are operating now.

The limitation of a liquid mirror is that it only points straight up, so it’s not like a standard telescope that can be pointed in any direction and track objects in the sky. It only looks at the area of sky that is directly overhead.

So, the scientific goal for a LMT is to not look over the whole sky, but to take one area of space and look at it intensely. This type of astronomy has been very “profitable,” as Angel described it, in terms of the wealth of information that?s been gathered. Some of the most productive scientific efforts from the Hubble Space Telescope have been its “Deep Field” photographs.

To be able to look at only one area of space at all times drives Angel and his team to look to one of the lunar poles for the best location for this telescope. As at Earth’s poles, looking straight up from the poles on the moon always provides the same extragalactic field of view. “If we go to the North or South Pole of the moon, we?re going to image one patch of sky all the time, and so that allows you to make an extremely deep integration, much deeper even than the Hubble Deep Field.” Combine that with a large aperture, and this telescope would provide a depth of observation which would be unmatched with any telescope on Earth or in space. “That?s the niche or particular strength of this telescope,” Angel said.

Another upside of liquid mirrors is that they are very inexpensive compared to the process of making a standard mirror by creating, polishing and testing a big, rigid piece of glass, or creating smaller pieces which have to be polished, tested and then joined together very accurately. Also, LMTs don’t need expensive mounts, supports, tracking systems, or a dome.

“The total cost of the James Webb Telescope is expected to exceed a billion dollars, with the price tag on the mirror alone around a quarter of a million dollars,” Angel said. “That mirror is 6 meters, so if we scale that technology to even bigger mirrors in space, we?re eventually going to break the bank, and we won?t be able to afford them by the present technology of making the polished mirror and getting it up to space.”

Even though the 2 meter telescope would be a prototype, it would still be astronomically valuable. “We could do things that are complimentary to the Spitzer Space Telescope and the Webb Telescope, as the 2 meter telescope on the moon would fill the territory in between those two telescopes.” A 20 meter mirror would provide resolution 3 times greater than the JWST, and by integrating, or leaving the “shutter” open for long periods, like a year, objects 100 times fainter could be viewed. A 100 meter mirror would provide data that is off the charts.

One of the challenges in developing an LMT on the moon is to create the bearings to spin the platform smoothly and at a constant speed. Air bearings are used for LMTs on Earth, but with no air on the moon, that is impossible. Angel and his team are looking at cryogenic levitation bearings, similar to what?s used for magnetic levitation trains to get a frictionless motion by using a magnetic field. Angel added, “As a bonus, with the low temperatures on the moon you can do that without expending any energy because you can make a superconducting magnet that allows you to make a levitation bearing that doesn’t require a continuous input of electrical power.”

Angel called the bearings a critical component of the telescope. “With no air on the moon to create wind, there?s no limit to size or reaching the accuracy that you require as long as the bearing is alright,” Angel said.

One evolution of the project since receiving the NIAC funding is the location of the telescope. In the initial proposal, Angel’s team favored the south pole of the moon in the Shackleton crater. But the north pole actually offers a better field of view for extragalactic observation, they realized, and Angel awaits data from the European Space Agency’s SMART-1 lunar orbiter that recently began surveying the polar regions of the moon.

“In the polar regions there are some craters where the sun never illuminates and never heats the ground,” Angel said. “It is extremely cold there, not too far above absolute zero. Rather than build the telescope under such hostile conditions, we would attempt to build the telescope on a peak of the either of the poles, where there would be sunshine almost continuously. This would provide solar power and the conditions would be better for the people living there. All you have to do is put a cylindrical Mylar screen around the telescope to prevent the sun from ever hitting it and it will cool off just like in the bottom of the craters.”

With infrared observing, a cold telescope is vital to be able to see colder and fainter objects in space. Having the telescope at near absolute zero (0 degrees Kelvin, -273 C, -460 F) would be ideal. Since mercury will freeze at those temperatures, another challenge for the project is finding the right liquid to spin for the mirror. Some of the candidates are ethane, methane, and other small hydrocarbons, like the liquids that were found on Titan by the Huygens probe, which landed on Saturn’s largest moon on January 14.

“But these liquids are not shiny, so you have to figure out how to deposit a shiny metal like aluminum directly onto the surface of the liquid,” Angel said. “Normally when we make an astronomical telescope we make the mirrors out of glass, which doesn?t reflect very much and then you evaporate aluminum or silver onto the glass. On the moon we would have to evaporate the metal onto the liquid rather than the glass.”

That’s one of the key areas of research under the NIAC award. In initial studies, Angel’s team has been able to evaporate a metal onto a liquid, although not yet at the cold temperatures required. However, they are encouraged by the results so far.

Angel’s team is atypical for a NIAC project, in that it’s an international collaboration, and NIAC doesn’t fund international partners. “It happens that the world experts on making spinning liquid mirror telescopes are all in Canada, so it was kind of essential that if we’re thinking of doing that on the moon that we bring them in,” Angel said. “Luckily, they have come in on their own ticket, so to speak, and are excited by the project.”

The Canadian members of the team are Emanno Borra, from Laval University in Quebec, who has been researching and building LMTs since the early 1980’s, and Paul Hickson, from University of British Columbia, who, with Borra’s help, built the 6 meter LMT in Vancouver. Other collaborators include Ki Ma at the University of Texas at Houston who is an expert on the cryogenic bearings, Warren Davison from the University of Arizona who is a mechanical engineering expert in telescopes, and graduate student Suresh Sivanandam.

NIAC was created in 1998 to solicit revolutionary concepts from people and organizations outside the space agency that could advance NASA’s missions. The winning concepts are chosen because they “push the limits of known science and technology,” and “show relevance to the NASA mission,” according to NASA. These concepts are expected to take at least a decade to develop.

Angel says that receiving the NIAC award is a great opportunity. “We will undoubtedly write a proposal for Phase II (of the NIAC funding),” he said. “We’ve identified during Phase I what are some of the most critical issues in this project, and what practical steps we should take now. We’ve opened some questions, and there are some simple tests we can do to see if there are any show stoppers or not.”

The biggest hurdle in making the Lunar Infrared Observatory a reality is, most likely, completely out of Angel’s hands. “The moon is a very interesting place to do science,” Angel said. “However, it’s predicated on a substantial commitment of resources by NASA to return to the moon.” Certainly, to build the large 20 or 100 meter telescopes there would have to be a manned presence on the moon. “So,” Angel continued, “by hitching your science in that direction, you become the tail of a very big dog over which you have absolutely no control”?

Angel hopes that NASA and the United States can maintain the momentum of the Vision for Space Exploration and return to the moon. “I think ultimately that moving out into space is something that humans have an urge to do and will do sometime,” Angel said. “When that happens, having interesting things to do once we get there is important. We have to know why we left the surface of this planet to go to the moon. We’re exploring, yes, but we can explore not only the moon, but use that as a place to do scientific research beyond the moon. I think it’s something that in the big picture should happen.”

Nancy Atkinson is a freelance writer and NASA Solar System Ambassador. She lives in Illinois.

Magnetic Bubble Could Protect Astronauts on Long Trips

A graphic of a superconducting magnetic bubble that could protect spacecraft. Credit: MIT.
A graphic of a superconducting magnetic bubble that could protect spacecraft. Credit: MIT.

It’s the year 2027 and NASA’s Vision for Space Exploration is progressing right on schedule. The first interplanetary spacecraft with humans aboard is on course for Mars. However, halfway into the trip, a gigantic solar flare erupts, spewing lethal radiation directly at the spacecraft. But, not to worry. Because of research done by former astronaut Jeffrey Hoffman and a group of MIT colleagues back in the year 2004, this vehicle has a state-of-the-art superconducting magnetic shielding system that protects the human occupants from any deadly solar emissions.

New research has recently begun to examine the use of superconducting magnet technology to protect astronauts from radiation during long-duration spaceflights, such as the interplanetary flights to Mars that are proposed in NASA’s current Vision for Space Exploration.

The principal investigator for this concept is former astronaut Dr. Jeffrey Hoffman, who is now a professor at the Massachusetts Institute of Technology (MIT).

Hoffman’s concept is one of 12 proposals that began receiving funding last month from the NASA Institute for Advanced Concepts (NIAC). Each gets $75,000 for six-months of research to make initial studies and identify challenges in developing it. Projects that make it through that phase are eligible for as much as $400,000 more over two years.

The concept of magnetic shielding is not new. As Hoffman says, “The Earth has been doing it for billions of years!”

Earth’s magnetic field deflects cosmic rays, and an added measure of protection comes from our atmosphere which absorbs any cosmic radiation that makes its way through the magnetic field. Using magnetic shielding for spacecraft was first proposed in the late 1960’s and early 70’s, but was not actively pursued when plans for long-duration spaceflight fell by the wayside.

However, the technology for creating superconducting magnets that can generate strong fields to shield spacecraft from cosmic radiation has only recently been developed. Superconducting magnet systems are desirable because they can create intense magnetic fields with little or no electrical power input, and with proper temperatures they can maintain a stable magnetic field for long periods of time. One challenge, however, is developing a system that can create a magnetic field large enough to protect a bus-sized, habitable spacecraft. Another challenge is keeping the system at temperatures near absolute zero (0 Kelvin, -273 C, -460 F), which gives the materials superconductive properties. Recent advances in superconducting technology and materials have provided superconductive properties at higher than 120 K (-153 C, -243 F).

There are two types of radiation that need to be addressed for long-duration human spaceflight, says William S. Higgins, an engineering physicist who works on radiation safety at Fermilab, the particle accelerator near Chicago, IL. The first are solar flare protons, which would come in bursts following a solar flare event. The second are galactic cosmic rays, which, although not as lethal as solar flares, they would be a continuous background radiation to which the crew would be exposed. In an unshielded spacecraft, both types of radiation would result in significant health problems, or death, to the crew.

The easiest way to avoid radiation is to absorb it, like wearing a lead apron when you get an X-ray at the dentist. The problem is that this type of shielding can often be very heavy, and mass is at a premium with our current space vehicles since they need to be launched from the Earth?s surface. Also, according to Hoffman, if you use just a little bit of shielding, you can actually make it worse, because the cosmic rays interact with the shielding and can create secondary charged particles, increasing the overall radiation dose.

Hoffman foresees using a hybrid system that employs both a magnetic field and passive absorption. “That’s the way the Earth does it,” Hoffman explained, “and there’s no reason we shouldn’t be able to do that in space.”

One of the most important conclusions to the second phase of this research will be to determine if using superconducting magnet technology is mass effective. “I have no doubt that if we build it big enough and strong enough, it will provide protection,” Hoffman said. “But if the mass of this conducting magnet system is greater than the mass just to use passive (absorbing) shielding, then why go to all that trouble?”

But that’s the challenge, and the reason for this study. “This is research,” Hoffman said. “I’m not partisan one way or the other; I just want to find out what’s the best way.”

Assuming Hoffman and his team can demonstrate that superconducting magnetic shielding is mass effective, the next step would be doing the actual engineering of creating a large enough (albeit lightweight) system, in addition to the fine-tuning of maintaining magnets at ultra-cold superconducting temperatures in space. The final step would be to integrate such a system into a Mars-bound spacecraft. None of these tasks are trivial.

The examinations of maintaining the magnetic field strength and the near-absolute zero temperatures of this system in space is already occurring in an experiment that is scheduled to be launched to the International Space Station for a three-year stay. The Alpha Magnetic Spectrometer (AMS) will be attached to the outside of the station and search for different types of cosmic rays. It will employ a superconducting magnet to measure each particle?s momentum and the sign of its charge. Peter Fisher, a physics professor also from MIT works on the AMS experiment, and is cooperating with Hoffman on his research of superconducting magnets. A graduate student and a research scientist are also working with Hoffman.

NIAC was created in 1998 to solicit revolutionary concepts from people and organizations outside the space agency that could advance NASA’s missions. The winning concepts are chosen because they “push the limits of known science and technology,” and “show relevance to the NASA mission,” according to NASA. These concepts are expected to take at least a decade to develop.

Hoffman flew in space five times and became the first astronaut to log more than 1,000 hours on the space shuttle. On his fourth space flight, in 1993, Hoffman participated in the first Hubble Space Telescope servicing mission, an ambitious and historic mission that corrected the spherical aberration problem in the telescope’s primary mirror. Hoffman left the astronaut program in 1997 to become NASA?s European Representative at the US Embassy in Paris, and then went to MIT in 2001.

Hoffman knows that to make a space mission possible, there’s a lot of idea development and hard engineering which precedes it. “When it comes to doing things in space, if you’re an astronaut, you go and do it with your own hands,” Hoffman said. “But you don?t fly in space forever, and I still would like to make a contribution.”

Does he see his current research as important as fixing the Hubble Space Telescope?

“Well, not in the immediate sense,” he said. “But on the other hand, if we ever are going to have a human presence throughout the solar system we need to be able to live and work in regions where the charged particle environment is pretty severe. If we can’t find a way to protect ourselves from that, it will be a very limiting factor for the future of human exploration.”