Reinventing Space Flight

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Reinventing Space Flight

Ancient people saw them as messages from the Gods, as supernatural winds that blew from the realm of spirits Modern science has linked these polar light shows, called auroras, to vast waves of electrified gas hurled in our direction by the sun Today, researchers from a whole new generation see this dynamic substance, plasma, as an energy source that may one day fuel humanity’s expansion into space What can we learn, and how far can we go, by tapping into the strange and elusive fourth state of matter? A small cadre of scientists has come to Fairbanks, Alaska… to realize what may seem an impossible dream… to revolutionize space travel Dr. Ben Longmier and his team from the University of Michigan have designed a whole new type of rocket engine that promises a faster and more efficient way to get around in space They are here to test components of this rocket by sending them aboard helium balloons to an altitude of 30 kilometers… into the harsh environment of space Above the north and south poles, conditions are about as harsh as you can get Our planet is bombarded with a steady steam of charged particles from the Sun Earth’s magnetic field accelerates and channels them, turning the night into a spectacle of color While most astronauts train to live and work in zero gravity, or to move around in bulky space suits, these would-be space explorers are preparing to negotiate some of Earth’s harshest environments Once they launch their payload, it will rise slowly into the upper atmosphere After drifting through the night, above 99% of Earth’s atmosphere, the payload will detach from the balloon and parachute down to the ground Where it goes and finally lands will depend on highly variable wind conditions The team must be prepared to retrieve it across a large stretch of Alaska’s snowy wilderness To understand the revolutionary nature of the idea they are pursuing, we go back to the dawn of rocketry In over a hundred years, the technology of a rocket has hardly changed Fill a cylinder with volatile chemicals, then ignite them in a controlled explosion

The force of the blast is what pushes the rocket up Nowadays, chemical rockets are the only ones with enough thrust to overcome Earth’s gravity and carry a payload into orbit But they are not very efficient The heavier the payload, the more fuel a rocket needs to lift it into space But the more fuel a rocket carries, the more fuel it needs One of the fabled Saturn V rockets of the Apollo era, for example, weighed in at 177,000 kilograms Filled up with fuel, it weighed almost 16 times that The space shuttle, with maximum payload, weighed about 100 thousand kilos Add tanks and fuel, and it lifted off at 2 million kilograms Regardless of weight, for a spacecraft to escape Earth’s gravity and go into orbit, it must reach a minimum speed of 40,000 kilometers per hour The energy needed to do that meant there wasn’t enough fuel for a sustained acceleration to more distant planetary shores Most missions beyond Earth have relied instead on their initial launch speed to coast to their destination The twin spacecraft of Voyager, for example, did not have enough speed to reach its current position at the edge of the solar system To give them a boost, flight planners sent them into Jupiter’s gravitational field, using its pull to sling shot them out to Saturn Voyager 2 got further assists from Saturn and Uranus Voyager 1 used Saturn to accelerate to almost 63,000 kilometers per hour Ben’s rockets promise far greater gas mileage than traditional chemical rockets, but with enough power to reach distant targets more quickly The idea is that once in space, his rockets use electricity to create a weak force, which over time can accelerate them to very high speeds They run on the same fuel that nature uses, literally, to power the cosmos Not long after its explosive beginnings, the universe was awash in vast stores of hydrogen gas But even as the universe continued to expand, gravity drew clumps of matter into ever-denser concentrations The earliest stars took shape, immense balls of hydrogen gas, hundreds of times the mass of our sun As they contracted inward, they heated up and ignited Intense radiation now began to flow through the voids That had the effect, all through the universe, of stripping electrons away from the primordial gas The universe became filled, not with solids, liquid, or gas, but with a fourth state of matter: plasma On our planet, plasma occurs only in rare circumstances: in a hot flame, a bolt of lightning, or in a blown electrical transformer Made up of negatively charged electrons and positively charged ions, plasma is in most

cases electrically neutral since the charges balance each other out That led the physicist Irving Langmuir in the 1920s to compare it to the clear liquid, plasma, that carries blood cells through our bodies The development of radio led to the discovery, high above the Earth, of a natural plasma ceiling, the ionosphere It hovers above us, reflecting some radio frequencies and absorbing others Its importance became clear when engineers noticed that radio waves could, under some conditions, travel beyond our line of sight They discovered that signals could be bounced deliberately off this conducting layer, in what’s called “skywave propagation.” In World War 2, a whole new age of global communications came of age when radio was used to execute complex worldwide logistics of troop and ship movements The presence of the ionosphere is due to a steady stream of charged particles, or plasma, that comes from the sun A spacecraft with complex computer components must be able to survive constant exposure to these particles As part of their design process, Ben and team want to test some of the specialized components of their rockets in the plasma-fill environment of our upper atmosphere Those components will be mounted on a simple frame attached by rope to a high-altitude balloon The frame is also outfitted with an array of novel sensors to take independent readings One holds a colony of bacteria The idea is that the bacteria itself can detect radiation So it mutates in a certain way or in a very known way so that if you send it into an environment with a lot of cosmic rays and perhaps a lot of x-rays from the aurora itself, it mutates And so we’ll detect sort of the level of radiation it’s exposed to by looking at these mutations after we’ve recovered the baceria after flying them to the edge of space in one of these balloon capsules Another is a series of tiny GoPro cameras converted to record the intensity of infrared and ultraviolet light normally hidden to the human eye The team uses Argon gas to insulate instruments against the cold, with chemical packets added for warmth They stabilize the frame with tiny gyroscopes, and outfit it with GPS devices for tracking This team is doing much more than just designing instruments to survive a rain of charged particles Their goal is to design spacecraft that actually harness the explosive properties of plasma Unlike most matter on Earth, plasma conducts electricity and responds to magnetic fields In space, these properties influence the formation of structures like galaxies and nebulae

And they play a role in some of the most violent processes in the universe, such as the formation of a black hole It forms in the wake of a giant star’s death, when matter collapses into its core It swirls in along what’s known as an accretion disk Magnetic fields take shape on the disk, rising and twisting around the polar regions They draw huge volumes of plasma up, then shoot it out at high speeds These plasma jets can extend far beyond the largest black holes You can see them blasting continuously from the centers of galaxies, reaching thousands of light years into space Studies of one giant nearby ball of plasma show what a complex and volatile substance it can be In the core of our sun, high heat and crushing pressures cause hydrogen atoms to crash together That sets off a nuclear reaction in which hydrogen atoms fuse into heavier ones like helium and carbon, generating heat This heat slowly rises to the surface of the sun in vast plumes of plasma You can see evidence of this process, called convection, in a pattern of ever-evolving blobs known as granules They are like the tops of thunderstorms Even as energy builds within, the sun’s gravity and density can stifle its escape What carries it out are magnetic fields They twist and wrap around, channeling energy to the surface The fields can power immense loops of hot gas, about 60,000 degrees Celsius, then rise up from the solar surface and fall back The largest eruptions, called coronal mass ejections, can reach up to 6 million miles per hour as they hurtle out across the solar system They can literally slam into Earth’s own magnetic field Because solar particles are charged, a portion follows the orientation of Earth’s magnetic field lines Finding an opening at the poles, these particles race down into the atmosphere You know this is happening when you see the beautiful lights of the aurora borealis in the far north, or the aurora australis in the south They appear when charged solar particles collide with oxygen molecules in the upper atmosphere, causing them to glow blue, red, and green depending on altitude Flying 350 kilometers above the earth, astronauts in the international space station watch in

awe as the aurora shimmers, framed by the glow of stars and cities at night Back in Michigan, Ben and his team have set up a lab to harness this strange substance in a whole new generation of rocket engines The lab recalls an earlier period of space exploration It features a giant vacuum chamber, built in the 1960s in hopes of winning a contract to test Apollo moon rovers The chamber has given this small university team the ability to accelerate their research into the physics of plasma and rocket engine design They are actually part of an larger community of plasma rocket scientists… within NASA… and within private companies like Ad Astra of Houston, Texas Because plasma does not occur naturally on Earth, the challenge is to create it, then harness it The teams inject a gas, commonly argon, into a chamber They bombard it with radio waves, which strip electrons from the gas and turn it into a plasma The soup of electrons and ions accelerates as it moves through a magnetic field generated by superconducting magnets A second radio blast heats it up to a million degrees Celsius That’s enough to blast it out and propel a spacecraft The idea of using plasma to power rockets is not a new one The Polish physicist Stanislav Ulam is said to have been inspired by atom bomb tests in the 1940s He speculated that waves of plasma from small nuclear detonations could propel a spacecraft to extreme speeds In the 1950s, that idea animated dreams of exploring the solar system in spacecraft like this 360-ton Mars-bound vehicle The idea gained funding in the Orion project, with the idea of driving a spacecraft with nuclear pulses and landing on Mars in only a month Concerns about radioactive exhaust helped doom the project Plasma rockets, energized by nuclear reactions, were revived in the Daedalus and Nerva projects of the 1960s, and again at the beginning of this century as part of a proposed journey to Jupiter’s moon Europa Rising costs killed that mission

Newer plasma rocket concepts have switched to solar energy to power their engines Among the most ambitious, the DAWN mission was sent into orbit aboard a Delta 2 rocket in the year 2007 It then headed out on a ten year mission to the asteroid belt It uses only about 10 ounces of xenon gas fuel per day With engines designed to fire for over 2000 days, over time it is expected to gain an additional 38,000 kilometers per hour After a gravity assist from Mars, Dawn arrived at the asteroid Vesta in 2011 It spent a year mapping its surface and seeking clues to its interior structure Now headed for Ceres, a dwarf planet located within the asteroid belt, Dawn will be the first probe ever visit Made up of rock and ice, Ceres may well have an internal ocean of water and ice It takes us back to the formation of the solar system, when objects like this grew and developed into planets Long range missions like Dawn are just one of many uses for plasma rockets So nasa launches spacecraft with ion engines and hall thrusters on board Almost every new geostationary satellite that a company will invest in and put up in orbit will have some sort of electric propulsion device on board to do station keeping, to do little changes in attitude and maneuvers to keep it in its geostationary orbit NASA is planning to use a plasma rocket to do some even heavier lifting, as early as 2016 Flying at an altitude of three hundred fifty kilometers, the International Space Station whips around the Earth every one and a half hours To stay aloft, it must maintain a speed of 28,000 kilometers per hour But its solar panels and crew modules smack into so many tiny molecules in the upper atmosphere that it gradually slows down and loses altitude To stay aloft, the station uses up around 4,000 kilograms of fuel per year That fuel must be flown up from Earth, which in turn reduces the amount of food, water, people, and equipment that a resupply mission can deliver The idea is to use a plasma rocket to help boost the station to a higher altitude, powered by electricity generated by solar panels aboard the station Plasma rocket builders like Ben hope to one day scale up the technology to power a long-range human mission After weeks spent accelerating in earth orbit, the rocket would make a break for Mars Cutting flight time from a year to several months would lower costs and crew hazards In the meantime, Ben has his sights set on what he sees as an even larger revolution in space exploration… using plasma rockets to power a fleet of miniature spacecraft

Ben’s rockets are so small they can fit into your carry-on luggage So here we have a cube sat This is a small spacecraft, it’s total mass would be something on the order of 5 kilograms, that’s about 10 pounds It’s 30 centimeters x 10 x 10 This is considered a 3U spacecraft , 3 units of 10x10x10 And we’d like to send this small spacecraft up with one of our new propulsion elements in it This is a rapid prototype propellant tank So we would use this tank to store our propellant Initially we have an idea to use a very simple propellant The NASA craft Dawn uses the inert gas, Xenon, as fuel Ben’s team has turned to another type of fuel, that’s more compact, can store more energy, and is less volatile Distilled water We’ll ionize that propellant with radio waves and that will form a plasma, so we’ll strip off some electrons We’ll have this sea and collection of ions and electrons We accelerate, we superheat that plasma and then we accelerate it through a magnetic nozzle The plasma never touches a material boundary so it never cools off All of that could be contained within the spacecraft so the propellant tank is designed to be the right size and dimension and we have a propulsion module within the cube sat itself This is an early prototype circuit board, just this component, that would sit inside the cube sat and it would take the DC power from some sort of solar panel on the surface, change that DC power into our radio waves that we need to ionize the propellant into a plasma We then shoot this plasma out the back and we apply just a little bit of force, it’s not a whole lot, it’s something like the force of a sheet of paper sitting in your hand And because there’s very little drag in space, we apply this small amount of force applied over a very long amount of time to accelerate to very high velocities with this spacecraft So if we do that we can send these little micro spacecraft, nanosats, we can send them to places like the moon, we can send them to mars, and someday we’d like to send them even as far as Jupiter and maybe put some little sensors on board and be able to detect possible life on some of these moons near Jupiter and Saturn So instead of a 1 billion dollar nasa mission to explore the moons of Jupiter, we can get away with something like a million dollar spacecraft mission with one of these small sats So that’s the real advantage, being able to have a very low barrier to entry financially and technologically to make some of these innovations really quickly, go fly them, go fly often, and make these discoveries Already, hundreds micro, nano, and even smaller satellites are in orbit They get into space by piggy backing on commercial or government launch vehicles Their missions range from communications and intelligence to Earth imaging Because the cost of building them is so low, the number of tiny satellite missions is on the rise With an array of plans already materializing, the team is tapping into satellite traffic and orbital communications systems Ben and his team plan to start with a series of orbital missions, then to go interplanetary Ben imagines that his little group could take center stage in a project that space visionaries have long seen as essential to the quest to extend our eyes and minds across the solar system We also envision that a large cadre of these small spacecraft could form what would be

an initial interplanetary internet You can think about a large number of these spacecraft orbiting the earth, orbiting the moon, being spread out between earth and mars, and providing little data relays between all of these positions so we can get a lot of data back and have the beginnings of a real solar system internet going beyond the Earth Back in Alaska Their latest payload has flown all night at an altitude of over 100,000 feet Then in the low air pressure, the balloon burst and the payload parachuted to the ground From GPS signals given off by the payload, they have a good idea of where it is But that doesn’t mean retrieving it will be easy Now we’re right here And see where it says Sled Road? That’s the trail we’re going to be following down John knows where there’s a cut off that’s going to take us off that Sled Road over to Dune Lake And this little pond or lake right here just to the west maybe a mile north is where we believe the target is So we’re going to come down here, we’re going to look for the turn, head off to Dune Lake and then we’re going to be off trail from here all the way up to here Wow About five miles Okay Then we’re going to have, both Hans and I have these GPS locater devices… So we’ve got our first payload, Aurora One, that we are going to go recover and track You see snow machines to recover We’ve got two expert guides that go track these things for a living One guy is a retired military helicopter pilot And we’ve got GPS units, all the coordinates plugged in We’re about 26 miles from here as the crow flies We’re about thirty, thirty-five miles by trail, the last five miles being really off trail so we’re going to have to break new trail The plan is to navigate well-worn snow trails and get within striking distance But if the payload has landed away from the trails, they’ll have to brave wilderness landscapes and deep snows It takes nearly all day to get to a point about seven miles from the payload Team members set out across hills and ravines They get to within two miles With time running out, they turn around It’s not going to happen today We’re going to go back, recoup, probably send a skeleton team down tomorrow and try for a second recovery Really disappointing we couldn’t get there I feel like we’re so close this thing came 50 miles from the initial launch site It was floating around in the atmosphere for ten hours, and it’s so frustrating to get to within two miles The next day, a long hike on snowshoes finally gets them to the payload Later on they’ll say it was worth the effort One of Ben’s goals is to help boost a whole new approach to space travel that’s now

emerging May 2012 marked a major milestone in the rise of free enterprise in space The SpaceX Company successfully docked an unmanned space capsule with the International Space Station It followed that up six months later with the first commercial resupply mission That’s just the beginning NASA is looking to companies to supply orbital launch services, and to be long-term partners in future manned missions beyond the moon Hoping to make big bucks, companies are developing orbital habitats and space planes, laying the groundwork for missions geared to mining, exploration, and even tourism To Ben, this new race to space will go to the swift and the innovative Today, because of weather and winds, he and his team have chosen to launch their payload from the spectacular Ruth Glacier in Denali National Park Amid the rugged terrain, this immense river of ice sweeps down into a perfect natural runway The payload and frame have been preassembled The team makes a few last-minute adjustments They inflate the balloon with helium gas With dusk approaching, balloon and payload are ready Off it goes The balloon drifts up through the dense polar air With night falling, it rises up to the edge of space Meanwhile, overhead, a solar storm is raging Aboard the International Space Station, astronaut Don Pettit is making observations of northern

aurorae to complement what Ben’s team finds He passes over the Arctic several times during the balloon’s flight The auroras he photographs are an indicator of the amount of solar particles that will pummel Ben’s rocket components This is a time of high solar activity, approaching the peak of an 11-year cycle The Arctic Circle is framed by a ring of dancing auroral lights Curtains of green and red and blue drape our planet’s graceful curve This university-based experiment operates on the remote edge of modern science… dominated by large international projects such as the Hubble Space Telescope, the International Space Station or the Large Hadron Collider So this technology that we are trying to miniaturize is significant in the sense that it sort of opens up new frontiers, in the same way that miniaturizing computer technology to a point where it fits in your pocket Everyone carries around a cell phone They have these miniature computers It does a lot of data processing It gets you to your destination by GPS That sort of technology didn’t exist 20 or 30 or 40 years ago when you have these big mainframe computers that were at national labs So we’re trying to change the paradigm of space exploration from the national lab case to the cell phone case, the miniature case, to be able to do a lot more and to improve our capability as a species Working small, Ben’s team believes they are onto something big Their goal is not only to open new avenues of space exploration, but to actually seize the initiative It’s a romantic idea of individuals challenging the odds and striking out to new frontiers With technologies that are getting smaller and more powerful, the obstacles to private space exploration appear to be falling Who will hold back this new breed of explorer?