Category: Space Exploration

WISE bed rest study participant Dorota. Image credit: ESA Click to enlarge
When the first women astronauts set foot on Mars, they may spare a thought for the 24 women who paved the way for lengthy space trips by giving three months of their lives to space science, two months of which involved staying in bed.

From March to May and from September to November, two different groups of 12 volunteers from eight European countries – the Czech Republic, Finland, France, Germany, the Netherlands, Poland, Switzerland, and the United Kingdom – took part in the Women International Space Simulation for Exploration (WISE) campaign on behalf of the European Space Agency (ESA), the French space agency (CNES), the Canadian Space Agency (CSA) and the US National Aeronautics and Space Administration (NASA).

The volunteers of the WISE femal bedrest study underwent numerous medical tests
They gathered at the MEDES Space Clinic in Rangueil Hospital in Toulouse, France, to take up an extraordinary challenge: a 60-day campaign of female bedrest. For two months, they had to lie down and undertake all daily activities in beds tilted at an angle of 6? below horizontal, so that their heads were slightly lower than their feet. This unusual position induces physiological changes similar to those experienced by astronauts in weightlessness.

The last volunteers of the second WISE campaign got up on 30 November, and are now undergoing rehabilitation and medical tests lasting until 20 December. Similar tests were conducted in the pre-bedrest period for comparison.

MEDES, the French Institute for Space Medicine and Physiology, organised the selection of the volunteers and provided medical, paramedical and technical staff to support the extensive science experiments.

The main objective of the WISE campaign has been to assess the roles of nutrition and physical exercise with adapted equipment in countering the adverse effects of prolonged microgravity conditions, in order to develop the counter-measures that will be required when future astronauts venture beyond the Earth orbit to explore other worlds.

The data collected by the international science teams during the WISE study will improve our knowledge of muscle condition, blood parameters, cardiovascular condition, coordination of movements, changes in endocrine and immune systems, metabolism, bone status, as well as psychological wellbeing. This will serve not only the future of human spaceflight, but our everyday lives on Earth too, by providing clues as to how to deal with osteoporosis, fight the ”metabolic syndrome?, which affects millions of sedentary workers who take insufficient physical exercise, assist recovery of bedridden patients, or prevent some cardiovascular conditions.

Twelve scientific teams from 11 countries – Belgium, Canada, Denmark, France, Germany, Italy, the Netherlands, Sweden, Switzerland, the United Kingdom and the United States – are involved in the study. It will take them several months to analyse their data and start publishing their findings. In order to answer certain scientific questions, a follow-up of the volunteers will continue for three more years.

?The WISE campaign has now come to a successful conclusion and I look forward to further campaigns in the future where there is this degree of international involvement and complexity?, said Didier Schmitt, Head of the Life Sciences Unit in ESA?s Directorate of Human Spaceflight, Microgravity and Exploration. ?Planning for future research is already under way with a programme of bedrest campaigns being prepared, covering the next three years. This will be a combination of short-term, intermediate and long-term bedrest studies, lasting 5, 21 and 60 days, respectively. A research announcement covering this period is due to be released in the near future as part of the European programme for Life and Physical Sciences and Applications using the ISS (ELIPS). A further two bedrest studies are planned, one in Berlin and the other at the DLR in Cologne and they have already been selected as part of the ESA Microgravity Applications Programme (MAP). These studies are currently awaiting the necessary funding, also from the ELIPS Programme.?

To mark the completion of the WISE 2005 campaigns, ESA, CNES and MEDES are to hold a press conference, together with representatives from NASA and CSA, science teams and volunteers from the second WISE campaign, at the “Cit? de l?Espace” in Toulouse on 13 December.

Media representatives wishing to attend this press conference are requested to apply using the attached form, which should be returned to the address shown at the bottom of the form.

For additional information, ESA has created a website on the WISE study at:
http://www.spaceflight.esa.int/wise

Original Source: ESA Portal

Planetary MicroBots. Image credit: NASA Click to enlarge
Interview with Penny Boston, Part I

If you want to travel to distant stars, or find life on another world, it takes a bit of planning. That’s why NASA has established NIAC, the NASA Institute for Advanced Concepts. For the past several years, NASA has been encouraging scientists and engineers to think outside the box, to come up with ideas just this side of science fiction. Their hope is that some of these ideas will pan out, and provide the agency with technologies it can use 20, 30, or 40 years down the road.

NIAC provides funding on a competitive basis. Only a handful of the dozens of proposals submitted are funded. Phase I funding is minimal, just enough for researchers to flesh out their idea on paper. If the idea shows merit, it then may get Phase II funding, allowing the research to continue from the pure-concept to the crude-prototype stage.

One of the projects that received Phase II funding earlier this year was a collaboration between Dr. Penelope Boston and Dr. Steven Dubowsky to develop “hopping microbots” capable of exploring hazardous terrain, including underground caves. If the project pans out, hopping microbots may some day be sent to search for life below the surface of Mars.

Boston spends a lot of time in caves, studying the microorganisms that live there. She is the director of the Cave and Karst Studies Program and an associate professor at New Mexico Tech in Socorro, New Mexico. Dubowsky is the director of the MIT Field and Space Robotics Laboratory at MIT, in Cambridge, Massachusetts. He is known in part for his research into artificial muscles.

Astrobiology Magazine interviewed Boston shortly after she and Dubowsky received their Phase II NIAC grant. This is the first of a two-part interview. Astrobiology Magazine (AM): You and Dr. Steven Dubowsky recently received funding from NIAC to work on the idea of using miniature robots to explore subsurface caves on Mars? How did this project come about?

Penny Boston (PB): We’ve been doing quite a lot of work in caves on Earth with an eye to looking at the microbial inhabitants of these unique environments. We think they can serve as templates for looking for life forms on Mars and other extraterrestrial bodies. I published a paper in 1992, with Chris McKay and Michael Ivanov, suggesting that the subsurface of Mars would be the last refuge of life on that planet as it became colder and drier over geological time. That got us into the business of looking into the subsurface on Earth. When we did, we discovered that there is an amazing array of organisms that are apparently indigenous to the subsurface. They interact with the mineralogy and produce unique biosignatures. So it became a very fertile area for us to study.

Getting into difficult caves even on this planet is not that easy. Translating that to robotic extraterrestrial missions requires some thought. We have good imaging data from Mars showing distinct geomorphological evidence for at least lava-tube caves. So we know that Mars has at least that one type of cave that could be a useful scientific target for future missions. It’s plausible to think that there are also other types of caves and we have a paper in press in an upcoming Geological Society of America Special Paper exploring unique cave-forming (speleogenetic) mechanisms on Mars. The big sticking point is how to get around in such rigorous and difficult terrain.

AM: Can you describe what you did in the first phase of the project?

PB: In Phase I, we wanted to focus on robotic units that were small, very numerous (hence expendable), largely autonomous, and that had the mobility that was needed for getting into rugged terrains. Based on Dr. Dubowsky’s ongoing work with artificial-muscle-activated robotic motion, we came up with the idea of many, many, tiny little spheres, about the size of tennis balls, that essentially hop, almost like Mexican jumping beans. They store up muscle energy, so to speak, and then they boink themselves off in various directions. That’s how they move.

credit:Render by R.D.Gus Frederick
Planetary Setting For Large-Scale Planetary Surface & Subsurface Exploration. Click image for larger view.
Image Credit: Render by R.D.Gus Frederick

We’ve calculated that we could probably pack about a thousand of these guys into a payload mass the size of one of the current MERs (Mars Exploration Rovers). That would give us the flexibility to suffer the loss of a large percentage of the units and still have a network that could be doing recon and sensing, imaging, and perhaps even some other science functions.

AM: How do all these little spheres co-ordinate with each other?

PB: They behave as a swarm. They relate to each other using very simple rules, but that produces a great deal of flexibility in their collective behavior that enables them to meet the demands of unpredictable and hazardous terrain. The ultimate product that we’re envisioning is a fleet of these little guys being sent to some promising landing site, exiting from the lander and then making their way over to some subsurface or other hazardous terrain, where they deploy themselves as a network. They create a cellular communication network, on a node-to-node basis.

AM: Are they able to control the direction in which they hop?

PB: We have aspirations for them ultimately to be very capable. As we move into Phase II, we’re working with Fritz Printz at Stanford on ultra-miniature fuel cells to power these little guys, which would enable them to be able to do a fairly complex array of things. One of those capabilities is to have some control over the direction in which they go. There are certain ways that they can be built that can allow them to preferentially go in one direction or another. It’s not quite as precise as it would be if they were wheeled rovers just going on a straight path. But they can preferentially cant themselves more or less in the direction that they wish to go. So we’re envisioning that they will have at least crude control over direction. But a lot of their value has to do with their swarm motion as an expanding cloud.

As wonderful as the MER rovers are, for the kind of science I do, I need something more akin to the insect robot idea pioneered by Rodney Brooks at MIT. Being able to tap into the model of insect intelligence and adaptation for exploration had long appealed to me. Adding that to the unique mobility provided by Dr. Dubowsky’s hopping idea, I think, can enable a reasonable percentage of these little units to survive the hazards of subsurface terrain – that just seemed like a magical combination to me.

HB: So in Phase I, did any of these actually get built?

PB: No. Phase I, with NIAC, is a six-months-long brain-straining, pencil-pushing study, to scope out the state of the art of the relevant technologies. In Phase II, we’re going to do a limited amount of prototyping and field-testing, over a two-year period. This is far less than what one might need for an actual mission. But, of course, that is NIAC’s mandate, to examine technology 10 to 40 years out. We’re thinking this is probably in the 10- to 20-year range.

AM: What kinds of sensors or scientific equipment do you imagine being able to put on these things?

PB: Imaging is clearly something that we would like to do. As cameras become incredibly tiny and robust, there are already units in the size range that could be mounted on these things. Possibly some of the units could be fitted with magnification capability, so one could look at the textures of the materials that they are landing on. Integrating images taken by tiny cameras on lots of different little units is one of the areas for future development. That’s beyond the scope of this project, but that’s what we’re thinking of for imaging. And then, certainly chemical sensors, being able to sniff and sense the chemical environment, which is very critical. Everything from tiny laser noses to ion-selective electrodes for gases.

We are envisioning having them not all identical, but rather an ensemble, with enough of the different kinds of units fitted out with different kinds of sensors so that the probability would still be high, even given fairly high losses of numbers of units, that we would still have a complete suite of sensors. Even though each individual unit cannot have a giant payload of sensors on it, you could have enough so that it could give significant overlap with its fellow units.

AM: Will it be possible to do biological testing?

PB: I think so. Particularly if you imagine the time frame that we’re looking at, with the advances that are coming online with everything from quantum dots to lab-on-a-chip devices. Of course, the difficulty is getting sample material to those. But when we’re dealing with little ground-contacting units like our hopping microbots, you might be able to position them directly over the material that they wish to test. In combination with microscopy and wider-field imagery, I think that the capability is there to do some serious biological work.

AM: Do you have an idea of what the milestones are that you’re hoping to hit during your two-year project?

PB: We’re anticipating that by March we may have crude prototypes that have the relevant mobility. But that may be overly ambitious. Once we do have mobile units, our plan is to do field testing in real lava-tube caves that we are doing science on in New Mexico.

The field site’s already tested. As part of Phase I the MIT group came out and I taught them a little bit about caving and what the terrain was actually like. It was a big eye-opener for them. It’s one thing to design robots for the halls of MIT, but it’s another thing to design them for real-world rocky environments. It was a very educational experience for us all. I think they have a pretty good idea what the conditions are that they have to meet with their design.

AM: What are those conditions?

PB: Extremely uneven terrain, lots of crevices that these guys could get temporarily jammed in. So we’ll need modes of operation that will allow them to extricate themselves, at least with a reasonable chance of success. The challenges of line-of-sight communication in a highly rough surface. Getting over big boulders. Getting stuck in little cracks. Things of that sort.

Lava is not smooth. The interior of lava tubes is intrinsically smooth after they’re formed, but there is a lot of material that shrinks and cracks and falls down. So there are rubble piles to get around and over, and a lot of elevational change. And these are things that conventional robots don’t have the capability to do.

Original Source: NASA Astrobiology

EAFTC computers in a space-ready flight chassis. Image credit: NASA/Honeywell. Click to enlarge
Unfortunately, the radiation that pervades space can trigger such glitches. When high-speed particles, such as cosmic rays, collide with the microscopic circuitry of computer chips, they can cause chips to make errors. If those errors send the spacecraft flying off in the wrong direction or disrupt the life-support system, it could be bad news.

To ensure safety, most space missions use radiation hardened computer chips. “Rad-hard” chips are unlike ordinary chips in many ways. For example, they contain extra transistors that take more energy to switch on and off. Cosmic rays can’t trigger them so easily. Rad-hard chips continue to do accurate calculations when ordinary chips might “glitch.”

NASA relies almost exclusively on these extra-durable chips to make computers space-worthy. But these custom-made chips have some downsides: They’re expensive, power hungry, and slow — as much as 10 times slower than an equivalent CPU in a modern consumer desktop PC.

With NASA sending people back to the moon and on to Mars–see the Vision for Space Exploration–mission planners would love to give their spacecraft more computing horsepower.

Having more computing power onboard would help spacecraft conserve one of their most limited resources: bandwidth. The bandwidth available for beaming data back to Earth is often a bottleneck, with transmission speeds even slower than old dial-up modems. If the reams of raw data gathered by the spacecraft’s sensors could be “crunched” onboard, scientists could beam back just the results, which would take much less bandwidth.

On the surface of the moon or Mars, explorers could use fast computers to analyze their data right after collecting it, quickly identifying areas of high scientific interest and perhaps gathering more data before a fleeting opportunity passes. Rovers would benefit, too, from the extra intelligence of modern CPUs.

Using the same inexpensive, powerful Pentium and PowerPC chips found in consumer PCs would help tremendously, but to do so, the problem of radiation-induced errors must be solved.

This is where a NASA project called Environmentally Adaptive Fault-Tolerant Computing (EAFTC) comes in. Researchers working on the project are experimenting with ways to use consumer CPUs in space missions. They’re particularly interested in “single event upsets,” the most common kind of glitches caused by single particles of radiation barreling into chips.

Team member Raphael Some of JPL explains: “One way to use faster, consumer CPUs in space is simply to have three times as many CPUs as you need: The three CPUs perform the same calculation and vote on the result. If one of the CPUs makes a radiation-induced error, the other two will still agree, thus winning the vote and giving the correct result.”

This works, but often it’s overkill, wasting precious electricity and computing power to triple-check calculations that aren’t critical.

“To do this smarter and more efficiently, we’re developing software that weighs the importance of a calculation,” continues Some. “If it’s very important, like navigation, all three CPUs must vote. If it’s less important, like measuring the chemical makeup of a rock, only one or two CPUs might be involved.”

This is just one of dozens of error-correction techniques that EAFTC pulls together into a single package. The result is much better efficiency: Without the EAFTC software, a computer based on consumer CPUs needs 100-200% redundancy to protect against radiation-caused errors. (100% redundancy means 2 CPUs; 200% means 3 CPUs.) With EAFTC, only 15-20% redundancy is needed for the same degree of protection. All of that saved CPU time can be used productively instead.

“EAFTC is not going to replace rad-hard CPUs,” cautions Some. “Some tasks, such as life support, are so important we’ll always want radiation hardened chips to run them.” But, in due course, EAFTC algorithms might take some of the data-processing load off those chips, making vastly greater computer power available to future missions.

EAFTC’s first test will be onboard a satellite called Space Technology 8 (ST-8). Part of NASA’s New Millennium Program, ST-8 will flight-test new, experimental space technologies such as EAFTC, making it possible to use them in future missions with greater confidence.
The satellite, scheduled for a 2009 launch, will skim the Van Allen radiation belts during each of its elliptical orbits, testing EAFTC in this high-radiation environment similar to deep space.

If all goes well, space probes venturing across the solar system may soon be using the exact same chips found in your desktop PC — just without the glitches.

Original Source: NASA News Release

Pete Conrad’s self portrait. Image credit: NASA. Click to enlarge.
Picture this: An astronaut, on the Moon, hunched down over a rock, hammer in hand, prospecting. Suddenly, over his shoulder, there’s a flash of light on the sun.

The radio crackles: “Explorer 1, come in. This is mission control.”

Explorer 1: “What’s up?”

Mission Control: “There’s been a solar flare, a big one. You need to take cover. The radiation storm could begin in as little as 10 minutes.”

Explorer 1: “Roger. I’m heading for the Moon Buggy now. Any suggestions?”

Mission control: “Yes. Make sure you protect your hips.”

Protect your hips?

That’s right. Protecting the hips may be a key to surviving solar storms. Other sensitive areas are the shoulders, spine, thighs, sternum and skull.

Why this odd list of body parts? The bones in these areas contain marrow — the “blood factory” of the body. Delicate bone marrow cells are especially vulnerable to solar storms; a major dose of solar protons coursing through the body could wipe them out. And without these blood-forming marrow cells churning out a steady stream of new blood cells, a person would run out of blood in as little as a week. A bone marrow transplant would be required–stat!–but they don’t do those on the Moon.

So to survive a solar radiation storm, your first priority must be to protect your bone marrow.

With NASA sending people back to the Moon by 2018, the issue of surviving solar radiation storms is more important than ever. Outside the protection of Earth’s magnetic field and with virtually no atmosphere overhead, an astronaut walking on the lunar surface is exposed to the full brunt of solar storms.

The best solution is to take cover, to get back to a radiation shelter. But if shelter is too far away to reach in time, wearing a spacesuit with extra radiation shielding over these key marrow-rich areas — shoulders, hips, spine, etc. — could mean the difference between living and dying.

“Bulking up the entire spacesuit with extra shielding might not be practical,” says Frank Cucinotta, NASA’s Chief Scientist at the Johnson Space Center, “because then the spacesuit would be too cumbersome.” Astronauts have to be able to walk, hop, bend over, reach for objects and tools. Too much shielding would make these simple moves impossible–hence the idea of selective shielding:

A layer of a plastic-like material called polyethylene only 1 cm thick could prevent acute radiation sickness. “For all but the worst flares, this would be enough to keep the astronaut’s blood system intact,” Cucinotta says. If as few as 5% of those marrow cells survive, the bone marrow will be able to regenerate itself, and the person will survive, no transplant required.

An astronaut, so shielded, might still develop long-term health problems: cancer, cataracts and other maladies. “No spacesuit can stop all solar protons,” explains Cucinotta. But if the blood supply survives, the astronaut will too, long enough to worry about the long term.

At the moment, this idea of designing a spacesuit to selectively shield the astronaut’s bone marrow is just that: an idea. Cucinotta says that many strategies are being considered for protecting the astronauts on the Moon. But the response to the idea of selective shielding has been positive, Cucinotta says. It might work.

If the idea catches on, post-Apollo spacesuits would look a little different, with beefy shoulders, wide hips, and bulbous helmets, among other things. Fashions change, sometimes for the better.

Original Source: Science@NASA Article

Spirit’s view of Mars. Image credit: NASA/JPL. Click to enlarge.
Remote-sensing orbiters, probes, landers and rovers are returning astonishing discoveries about our solar system. But some of the most exciting geological and potentially astrobiological places in our family of planets and moons are dangerous and difficult to explore.

University of Arizona, California Institute of Technology, and U.S. Geological Survey Flagstaff researchers propose a novel space mission concept for finding and exploring the most scientifically important surfaces and subsurfaces throughout the solar system.

These next-generation robotic missions will simultaneously explore distant locales at several levels – from orbit, from the air and on the ground – to home in on important geology, hydrology, climate and possibly astrobiology in distant worlds, said James M. Dohm of The University of Arizona. Dohm, a planetary geologist in UA’s department of hydrology and water resources, has mapped Mars at local to global scales. He is involved with autonomous long-range roving, sensor web and orbiting spacecraft experiments.

Wolfgang Fink, a visiting associate at Caltech, Dohm and others discuss the new mission concept in an article, “Next-generation robotic planetary reconnaissance missions: A paradigm shift,” to be published in Elsevier?s journal of Planetary and Space Science (http://www.elsevier.com/, go to Article in Press link). They spearheaded a team effort that includes Mark Tarbell, who is Fink’s associate in Caltech’s Visual and Autonomous Exploration Systems Research Lab; Trent Hare of the U.S. Geological Survey office in Flagstaff; and Victor Baker, Regents’ Professor of the UA departments of hydrology and water resources, planetary sciences and geosciences.

The new mission concept would feature orbiting spacecraft, blimps and balloons at planets or moons with sufficient atmospheres, such as Titan, and numerous simple, deployable mobile and immobile ground sensors. These spaceborne, airborne, and ground agents would be programmed to look smartly at the environment and interact with each other, offering a true “tier-scalable” perspective needed for a science-driven mission, Dohm said.

“We are now at an optimal window in time when spacecraft and airborne units can coordinate with ground-based sensors, especially since much of the technology is already available,” said Fink, a physicist and an expert in imaging systems, autonomous control and space mission science analysis systems. “Even technology not currently available — software, primarily — is quite attainable.”

?It’s important to look at layers and layers of evidence, not just one type,” Dohm said.

For example, Fink said, a rover with feature-recognition software can look for a unique rock that could contain a critical piece of the history of Mars. “If you add an airborne perspective, you also see what?s on the other side of the hill at the same time, and you know the rover’s exact field location as well,” he said. The orbiter has the global picture of what’s going on and commands the airborne and ground tiers below it.

The orbiter in a tier-scalable mission is equipped with current information about the surface, atmosphere and other features of its destination. Its sensor suite might include optical and thermal cameras, spectrometers, and ground-penetrating radar. These instruments would collect information on areas that the orbiter’s software recognizes as possible interesting targets given the overall mission science goals.

“The orbiter can deploy the airborne agents for a closer look,” Fink said. “The orbiter also can command the airborne agents to safely deploy ground agents to the prime targets. The airborne agents help detect and confirm prime targets.”

“The ground agents can measure information such as heat or moisture,” Dohm said. “Or they can sample or collect diverse rocks and, in the case of Mars, possible near-surface water. There could be numerous lightweight, expendable sensors, so that even if you lost a few, you’d still have mission.”

The sensors send information back to their respective airborne probes, and ultimately to the orbiting spacecraft. Based on this new information, the orbiter sends new commands that drive the mission.

“The spaceborne, airborne, and ground agents all work together as a field geologist,” Dohm said. “They analyze information to form a working hypothesis.” They would be ideal for exploring Valles Marineris, the expansive canyon system of Mars, or Europa’s putative ice-covered ocean, he added.

In the case of Valles Marineris, for instance, Dohm said, the orbiting spacecraft would deploy sensors that would transmit weather conditions back to the spacecraft. If the sensors give the spacecraft a good weather report – no high winds, for example – the spacecraft would then release the balloons or blimps. These airborne agents would start their searches for targets important to mission goals, collecting and adding new information as they go and deploying ground agents at promising candidate sites. The ground agents would collect and return data to the higher-level airborne probes, or the orbiter, or both. “If the goal at Valles Marineris was to find possible water seeps or near-surface water, a drill rig might even be deployed at the most promising site,” Dohm said.

Fink and Dohm say the new concept needs further design, testing and ground-truthing in diverse Earth environments. They envision field camps for international researchers for designing and testing possible tier-scalable reconnaissance systems.

Intelligent, science-driven robotic space missions are a decade or two in the future, they will be international, and they will have significant corporate and private sponsorship, Dohm and Fink predict.

Original Source: University of Arizona News Release

An artist’s rendering of the Integrated Powerhead Demonstrator. Image credit: NASA. Click to enlarge.
When you think of future rocket technology, you probably think of ion propulsion, antimatter engines and other exotic concepts.

Not so fast! The final chapter in traditional liquid-fueled rockets has yet to be written. Research is underway into a new generation of liquid-fueled rocket designs that could double performance over today’s designs while also improving reliability.

Liquid-fueled rockets have been around for a long time: The first liquid-powered launch was performed in 1926 by Robert H. Goddard. That simple rocket produced roughly 20 pounds of thrust, enough to carry it about 40 feet into the air. Since then, designs have become sophisticated and powerful. The space shuttle’s three liquid-fueled onboard engines, for instance, can exert more than 1.5 million pounds of combined thrust en route to Earth orbit.

You might assume that, by now, every conceivable refinement in liquid-fueled rocket designs must have been made. You’d be wrong. It turns out there’s room for improvement.

Led by the US Air Force, a group consisting of NASA, the Department of Defense, and several industry partners are working on better engine designs. Their program is called Integrated High Payoff Rocket Propulsion Technologies, and they are looking at many possible improvements. One of the most promising so far is a new scheme for fuel flow:

The basic idea behind a liquid-fueled rocket is rather simple. A fuel and an oxidizer, both in liquid form, are fed into a combustion chamber and ignited. For example, the shuttle uses liquid hydrogen as its fuel and liquid oxygen as the oxidizer. The hot gases produced by the combustion escape rapidly through the cone-shaped nozzle, thus producing thrust.

The details, of course, are much more complicated. For one, both the liquid fuel and the oxidizer must be fed into the chamber very rapidly and under great pressure. The shuttle’s main engines would drain a swimming pool full of fuel in only 25 seconds!

This gushing torrent of fuel is driven by a turbopump. To power the turbopump, a small amount of fuel is “preburned”, thus generating hot gases that drive the turbopump, which in turn pumps the rest of the fuel into the main combustion chamber. A similar process is used to pump the oxidizer.

Today’s liquid-fueled rockets send only a small amount of fuel and oxidizer through the preburners. The bulk flows directly to the main combustion chamber, skipping the preburners entirely.

One of many innovations being tested by the Air Force and NASA is to send all of the fuel and oxidizer through their respective preburners. Only a small amount is consumed there–just enough to run the turbos; the rest flows through to the combustion chamber.

This “full-flow staged cycle” design has an important advantage: with more mass passing through the turbine that drives the turbopump, the turbopump is driven harder, thus reaching higher pressures. Higher pressures equal greater performance from the rocket.

Such a design has never been used in a liquid-fueled rocket in the U.S. before, according to Gary Genge at NASA’s Marshall Space Flight Center. Genge is the Deputy Project Manager for the Integrated Powerhead Demonstrator (IPD)–a test-engine for these concepts.

“These designs we’re exploring could boost performance in many ways,” says Genge. “We’re hoping for better fuel efficiency, higher thrust-to-weight ratio, improved reliability–all at a lower cost.”

“At this phase of the project, however, we’re just trying to get this alternate flow pattern working correctly,” he notes.

Already they’ve achieved one key goal: a cooler-running engine. “Turbopumps using traditional flow patterns can heat up to 1800 C,” says Genge. That’s a lot of thermal stress on the engine. The “full flow” turbopump is cooler, because with more mass running through it, lower temperatures can be used and still achieve good performance. “We’ve lowered the temperature by several hundred degrees,” he says.

IPD is meant only as a testbed for new ideas, notes Genge. The demonstrator itself will never fly to space. But if the project is successful, some of IPD’s improvements could find their way into the launch vehicles of the future.

Almost a hundred years and thousands of launches after Goddard, the best liquid-fueled rockets may be yet to come.

Original Source: NASA Science Article

Artist illustration of the new Crew Exploration Vehicle. Image credit: Northrop Grumman. Click to enlarge.
A Northrop Grumman-Boeing team has unveiled its plans to design and build NASA’s proposed Crew Exploration Vehicle, a successor to the space shuttle that will carry humans to the International Space Station by 2012 and back to the moon by 2018. Shown in these artist concepts, the new, modular space vehicle comprises a crew module reminiscent of the Apollo spacecraft, a service module and a launch-abort system.

A Northrop Grumman-Boeing team has unveiled its plans to design and build NASA’s proposed Crew Exploration Vehicle, a successor to the space shuttle that will carry humans to the International Space Station by 2012 and back to the moon by 2018. Shown in these artist concepts, the new, modular space vehicle comprises a crew module reminiscent of the Apollo spacecraft, a service module and a launch-abort system.

The CEV comprises a crew module that builds on NASA’s Apollo spacecraft, a service module and a launch-abort system. It is designed to be carried into space aboard a shuttle-derived launch vehicle — a rocket based on the solid rocket booster technology that powers the early phases of current shuttle flights.

The CEV will be produced both as a crewed space transportation system and as an uncrewed space vehicle capable of transporting cargo to and from the International Space Station. NASA expects to select a CEV prime contractor in the spring of 2006.

According to Doug Young, program manager for the Northrop Grumman-Boeing CEV team, the team’s design approach to the CEV and the overall mission architecture have been evolving over the past year.

“We’ve been working closely with NASA to identify design options and technologies that would enable the nation to meet its space exploration goals of safety, affordability and reliability,” Young said. “Early on we concluded that this modular, capsule-based approach would establish an ideal foundation for a successful, sustainable human and robotic space exploration program. It’s also a system that can be designed and built today using proven technologies, which will help maintain the nation’s leadership role in human space flight.”

While similar in shape to the Apollo spacecraft that carried astronauts to the moon in the late ’60s and early ’70s, the new CEV is a quantum leap forward in terms of performance, reliability and on-orbit mission capability.

“The CEV we plan to build will benefit not so much from a single, technical breakthrough but rather from evolutionary improvements in structural technologies, electronics, avionics, thermal-management systems, software and integrated system- health-management systems over the past 40 years,” said Leonard Nicholson, the Northrop Grumman-Boeing team’s deputy program manager.

According to Nicholson, the CEV offers many fundamental improvements over Apollo. Among them:

– CEV’s crew module will have much more internal volume than the Apollo capsule, but will only be slightly heavier, due to the use of advanced structural materials and technologies that reduce the size, weight and power consumption of key subsystems.

– CEV’s crew module will carry up to six astronauts, while Apollo carried just three.

– CEV will carry more fuel for lunar return than Apollo, allowing it to change its orbit rather than relying on the moon and the Earth to be in the right relative positions.

– CEV will be able to operate as an autonomous spacecraft orbiting the moon for up to six months while its crew of four descends to the lunar surface in the lunar lander. Crew members and ground controllers will be able to communicate with the CEV and monitor its “vital signs” remotely. During the Apollo era, one astronaut stayed with the “mother ship” while the lunar lander carrying two astronauts descended to the moon.

– CEV will use two fault-tolerant subsystems and integrated system-health- management systems to allow it to detect, isolate and recover from subsystem failures. By comparison, Apollo generally had only single fault tolerance.

A unit of The Boeing Company, Boeing Integrated Defense Systems is one of the world’s largest space and defense businesses. Headquartered in St. Louis, Boeing Integrated Defense Systems is a $30.5 billion business. It provides network-centric system solutions to its global military, government and commercial customers. It is a leading provider of intelligence, surveillance and reconnaissance systems; the world’s largest military aircraft manufacturer; the world’s largest satellite manufacturer and a leading provider of space-based communications; the primary systems integrator for U.S. missile defense; NASA’s largest contractor; and a global leader in sustainment solutions and launch services.

Northrop Grumman Corporation is a global defense company headquartered in Los Angeles, Calif. It provides technologically advanced, innovative products, services and solutions in systems integration, defense electronics, information technology, advanced aircraft, shipbuilding and space technology. With more than 125,000 employees, and operations in all 50 states and 25 countries, the company serves U.S. and international military, government and commercial customers. Today, more than 20,000 of Northrop Grumman’s employees are devoted to space-related projects.

Original Source: Northrop Grumman News Release

Paul Campbell took this amazing picture of the Moon. Image credit: Paul Campbell. Click to enlarge.
ILEWG is a public forum sponsored by the world’s space agencies to support “international cooperation towards a world strategy for the exploration and utilization of the Moon – our natural satellite”. An example objective is the ready and free sharing of data to any and all parties. This allows for judicious review and most importantly avoids duplication. Also, by coordinating onboard experiments beforehand, agencies can avoid duplicating research and wasting scarce funding. Given the costs and risks associated with each expedition, together with the scarcity of public funds, avoiding duplication is a necessary goal.

Exploring the Moon never stopped after the Apollo program. However, researchers have had to fight for funding on an equal basis with every other government department. In consequence, the number of missions have been few and far between. Now, only one satellite, Smart-1, orbits the Moon. This will change. For returning to the Moon, setting up a base, and then continuing on to Mars, we will need to know more of the Moon to minimize the cost and maximize the benefit. The Holy Grail for lunar exploration is water ice. Finding sufficient, recoverable quantities would greatly facilitate a human presence (as in drinking water) and further exploration (as in rocket fuel production). Without water ice, we either use brute force to raise sufficient quantities out of Earth’s gravity well or invent new techniques. Both these represent signficantly greater challenges. Nevertheless, the researchers at ILEWG are well aware of their knowledge gaps and are actively preparing missions to fill these in.

Yet the ILEWG participants aren’t accepting the status quo with NASA being the only player in town. In addition to other national space agencies, there were many individuals and corporations who were promoting their own style of space exploration and utilization. Lunar telescopes, mines and tourist hotels were just some opportunities deemed potential. To facilitate these ventures, conference attendees were treated to lectures on property rights, the common heritage of humankind and investment financing. For instance, without any arbitration medium, imagine sitting at your new observatory on the moon only to feel blasting from a nearby mining operation! These additional conference contributors, and their ability to think outside the box, demonstrate the desire and ability of the big, independent players at ILEWG.

However, even though great thinkers and doers were present, this doesn’t guarantee a lunar ‘gold rush’ happening any time soon. After all, if there were quick riches to be made, we would have had colonies already turning the lunar regolith into Swiss cheese. Instead, we’ve had to rely on public funds, i.e. taxpayer’s dollars. And unless some unforeseen magic appears, we will need a huge amount of this money to build a suitable infrastructure to reliably establish a human presence on the Moon’s surface. This showcases one omission from ILEWG. Very little attention was given to promoting lunar and space activities to the general public. Given the incessant demand for public funds that comes from every quarter, there needs to be solid and continual vindication for lunar base allocations. Alongside the great thinkers and doers, we need exuberant public relations experts to sell this endeavour.

Without the public’s interest, we will neither establish lunar colonies nor ever move off of Earth. The preponderance of technical data and investigations at the ILEWG conference demonstrate that we have the technical ability. But where is the justification? There is precious little economic justification. The monetary cost and consumption of Earth’s natural resources for people to live and work on the Moon is far greater than the equivalent cost of doing business on Earth. Further, the Moon has no unique qualities, after all, the Moon’s surface is very similar to the Earth’s. So, though service and resource providers may facilitate lunar colonies, they will not economically create such a colony.

But I am a believer. We need to step off of Earth and give ourselves a future that encompasses more than this one planet. We know our planet’s environment changes drastically. We know large asteroids regularly pummel the Earth’s surface. We know our Sun’s radiation fluctuates and the Sun itself will undergo a final tumultuous collapse. Restricting our children to the confines of the Earth’s surface is an artificial limiter that prevents our species from being the best it can be. We can do better. So get involved, talk to people, remind them that space is still a new harsh environment onto which we have barely stepped. Make them believe in a future more challenging and rewarding than simply lying on the ground at night wondering what the shiny dots above might be.

Whether, homesteaders, governments or organizations are the instigators, the Moon is our stepping stone off the Earth. The organization ILEWG is helping coordinate research and exploration amongst nations to quicken the building of our society off world. The gravity well that is Earth will remain for as long as the Earth so let’s acknowledge this, not as a barrier, but as a test to our civilization. Let’s work together and pass this test and decide our future, or we will stay moribund on Earth waiting for the future to decide our fate.

Written by Mark Mortimer

Astronaut on the Moon surface. Image credit: NASA Click to enlarge
A breakthrough by a team of British, US and French scientists will help protect astronauts, spacecraft and satellites from radiation hazards experienced in space.

Reporting in the journal Nature this week, the team describe how their study of rare and unusual space storms provided a unique opportunity to test conflicting theories about the behaviour of high energy particles in the Van Allen radiation belts* – a volatile region 12000 miles (19,000 km) above the Earth.

Lead author, Dr Richard Horne of the British Antarctic Survey (BAS) says

?Solar storms can increase radiation in the Van Allen belts to levels that pose a threat to spacecraft. As modern society relies increasingly on satellites for business, communications, and security, it is important to understand the environment that spacecraft operate in so that we can help protect our space investment.

?For a long time scientists have been trying to explain why the number of charged particles inside the belts vary so much. Our major breakthrough came when we observed two rare space storms that occurred almost back-to-back in October and November 2003. During the storms part of the Van Allen radiation belt was drained of electrons and then reformed much closer to the Earth in a region usually thought to be relatively safe for satellites.

? When the radiation belts reformed they did not increase according to a long-held theory of particle acceleration. Instead, by using scientific instruments in Antarctica and on the CLUSTER mission satellites, we showed that very low frequency radio waves caused the particle acceleration and intensified the belts.

?This new information will help spacecraft operators and space weather forecasters who must predict when satellites and missions are most at risk from radiation events allowing them to take measures to protect instruments and systems from damage, and astronauts from risks to their health.?

Original Source: BAS News Release

Artist’s concept of humans set off to Mars. Image credit: NASA Click to enlarge
After reading this article, you might never look at trash bags the same way again.

We all use plastic trash bags; they’re so common that we hardly give them a second thought. So who would have guessed that a lowly trash bag might hold the key to sending humans to Mars?

Most household trash bags are made of a polymer called polyethylene. Variants of that molecule turn out to be excellent at shielding the most dangerous forms of space radiation. Scientists have long known this. The trouble has been trying to build a spaceship out of the flimsy stuff.

But now NASA scientists have invented a groundbreaking, polyethylene-based material called RXF1 that’s even stronger and lighter than aluminum. “This new material is a first in the sense that it combines superior structural properties with superior shielding properties,” says Nasser Barghouty, Project Scientist for NASA’s Space Radiation Shielding Project at the Marshall Space Flight Center.

To Mars in a plastic spaceship? As daft as it may sound, it could be the safest way to go.

Less is more

Protecting astronauts from deep-space radiation is a major unsolved problem. Consider a manned mission to Mars: The round-trip could last as long as 30 months, and would require leaving the protective bubble of Earth’s magnetic field. Some scientists believe that materials such as aluminum, which provide adequate shielding in Earth orbit or for short trips to the Moon, would be inadequate for the trip to Mars.

Barghouty is one of the skeptics: “Going to Mars now with an aluminum spaceship is undoable,” he believes.

Plastic is an appealing alternative: Compared to aluminum, polyethylene is 50% better at shielding solar flares and 15% better for cosmic rays.

The advantage of plastic-like materials is that they produce far less “secondary radiation” than heavier materials like aluminum or lead. Secondary radiation comes from the shielding material itself. When particles of space radiation smash into atoms within the shield, they trigger tiny nuclear reactions. Those reactions produce a shower of nuclear byproducts — neutrons and other particles — that enter the spacecraft. It’s a bit like trying to protect yourself from a flying bowling ball by erecting a wall of pins. You avoid the ball but get pelted by pins. “Secondaries” can be worse for astronauts’ health than the original space radiation!

Ironically, heavier elements like lead, which people often assume to be the best radiation shielding, produce much more secondary radiation than lighter elements like carbon and hydrogen. That’s why polyethylene makes good shielding: it is composed entirely of lightweight carbon and hydrogen atoms, which minimizes secondaries.

These lighter elements can’t completely stop space radiation. But they can fragment the incoming radiation particles, greatly reducing the harmful effects. Imagine hiding behind a chain-link fence to protect yourself in a snowball fight: You’ll still get some snow on you as tiny bits of snowball burst through the fence, but you won’t feel the sting of a direct hit from a hard-packed whopper. Polyethylene is like that chain link fence.

“That’s what we can do. Fragmenting — without producing a lot of secondary radiation — is actually where the battle is won or lost,” Barghouty says.

Made to order

Despite their shielding power, ordinary trash bags obviously won’t do for building a spaceship. So Barghouty and his colleagues have been trying to beef-up polyethylene for aerospace work.

That’s how Shielding Project researcher Raj Kaul, working together with Barghouty, came to invent RXF1. RXF1 is remarkably strong and light: it has 3 times the tensile strength of aluminum, yet is 2.6 times lighter — impressive even by aerospace standards.

“Since it is a ballistic shield, it also deflects micrometeorites,” says Kaul, who had previously worked with similar materials in developing helicopter armor. “Since it’s a fabric, it can be draped around molds and shaped into specific spacecraft components.” And because it’s derived from polyethylene, it’s an excellent radiation shield as well.

The specifics of how RXF1 is made are secret because a patent on the material is pending.

Strength is only one of the traits that the walls of a spaceship must have, Barghouty notes. Flammability and temperature tolerance are also important: It doesn’t matter how strong a spaceship’s walls are if they melt in direct sunlight or catch fire easily. Pure polyethylene is very flammable. More work is needed to customize RXF1 even further to make it flame and temperature resistant as well, Barghouty says.

The Bottom Line

The big question, of course, is the bottom line: Can RXF1 carry humans safely to Mars? At this point, no one knows for sure.

Some “galactic cosmic rays are so energetic that no reasonable amount of shielding can stop them,” cautions Frank Cucinotta, NASA’s Chief Radiation Health Officer. “All materials have this problem, including polyethylene.”

Cucinotta and colleagues have done computer simulations to compare the cancer risk of going to Mars in an aluminum ship vs. a polyethylene ship. Surprisingly, “there was no significant difference,” he says. This conclusion depends on a biological model which estimates how human tissue is affected by space radiation–and therein lies the rub. After decades of spaceflight, scientists still don’t fully understand how the human body reacts to cosmic rays. If their model is correct, however, there could be little practical benefit to the extra shielding polyethylene provides. This is a matter of ongoing research.

Because of the many uncertainties, dose limits for astronauts on a Mars mission have not been set, notes Barghouty. But assuming that those dose limits are similar to limits set for Shuttle and Space Station flights, he believes RXF1 could hypothetically provide adequate shielding for a 30 month mission to Mars.

Today, to the dump. Tomorrow, to the stars? Polyethylene might take you farther than you ever imagined.

Original Source: NASA News Release