NASA’s New Look

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NASA unveiled a new look for its website over the weekend, and hopes that blogs, interactive features, and a customizable layout will especially appeal to 18-25 year olds.

A New York Times article reported that NASA is concerned that the social networking generation hasn’t shown enough interest in NASA, and the space agency hopes their new webpage will attract the MySpace crowd. This is the first major overhaul for NASA’s website since 2003, and NASA now hopes to compete with Space.com and CNN’s more chic presentations of space exploration. Numerous rollovers, links, and spectacular graphics can keep a visitor engaged for quite awhile, and readers can now Digg, del.icio.us or StumbleUpon stories that they like or want to share. The “Image of the Day” Gallery also benefited with a much-needed upgrade.

Critical Mass, the company that assisted NASA with the new design, says on their website that NASA’s site will now “inspire, involve and inform” and will unify over 3,500 different sites into a “cohesive information gateway.”

One past criticism of the different NASA webpages is that there was sometimes redundant or conflicting information. Critical Mass and their partner eTouch Systems claim the new site will fuel NASA’s efforts to “reconnect with the public and re-capture significance as one of the world’s most visionary and imaginative organizations.”

Still, Brian Dunbar, Internet Services Manager for NASA estimates that even before the overhaul, NASA’s website received approximately one million unique visitors each month. Not bad for an aging, old-fashioned, 50-year old.

Chime in with your thoughts about NASA’s revamped webpage on the BAUT Forum.

Original Source: New York Times

Meteorites Reveal Mars’ Past: Molten Surface, Thick Atmosphere

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If Mars ever had water flowing on its surface, as the many canyons and riverbed-like features on the Red Planet seem to indicate, it also would have needed a thicker atmosphere than what encircles that planet today. New research has revealed that Mars did indeed have a thick atmosphere for about 100 million years after the planet was formed. But the only thing flowing on Mars’ surface at that time was an ocean of molten rock.

A study of Martian meteorites found on Earth shows that Mars had a magma ocean for millions of years, which is surprisingly long, according to Qing-Zhu Yin, assistant professor of geology at the University of California- Davis. For such a persistent event, a thick atmosphere had to blanket Mars to allow the planet to cool slowly.

Meteorites called shergottites were studied to document volcanic activities on Mars between 470 million and 165 million years ago. These rocks were later thrown out of Mars’ gravity field by asteroid impacts and delivered to Earth — a free “sample return mission” as the scientists called it — accomplished by nature.

By precisely measuring the ratios of different isotopes of neodymium and samarium, the researchers could measure the age of the meteorites, and then use them to work out what the crust of Mars was like billions of years before that. Previous estimates for how long the surface remained molten ranged from thousands of years to several hundred million years.

The research was conducted by the Lunar and Planetary Institute, UC Davis and the Johnson Space Center.

Planets form by dust and rocks coming together to form planetisimals, and then these small planets collide together to form larger planets. The giant collisions in this final phase would release huge amounts of energy with nowhere to go except back into the new planet. The rock would turn to molten magma and heavy metals would sink to the core of the planet, releasing additional energy. The molten mantle eventually cools to form a solid crust on the surface.

Although Mars appears to no longer be volcanically active, NASA’s Mars Global Surveyor Spacecraft discovered that the Red Planet hasn’t completely cooled since its formation 4.5 billion years ago. Data from MGS in 2003 indicated that Mars’ core is made either of entirely liquid iron, or it has a solid iron center surrounded by molten iron.

Original News Source: UC Davis Press Release

NASA Tests New Parachutes for Ares Spacecraft

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This has been an exciting week for NASA’s Constellation program — the missions that will bring humans back to the Moon. Earlier in the week, NASA announced plans for testing abort systems and inflatable Moon habitats.

But on Thursday, November 15 actual tests were conducted for some of the genuine hardware that will be used for the Ares launch vehicles.

Near Yuma, Arizona, engineers tested the parachutes that will bring boosters from the first stage of the massive Ares rockets back to Earth.

Certainly, parachutes and rocket booster recovery is nothing new for NASA. But this new parachute is a whopper. Spanning 150 feet across and weighing 2,000 pounds makes this the largest chute of its kind ever tested for parachutes that will carry some of the heaviest payloads ever delivered.

And the new parachute worked perfectly — if not patriotically — with its red, white and blue striped canopy. Made of Kevlar, which is stronger and lighter than the nylon chutes used for the space shuttle’s solid rocket booster recovery, these bigger and stronger parachutes can still fit into the same size canister used for the shuttle boosters but yet be lighter.

Although the Ares boosters will actually come down in the Atlantic Ocean, the tests were conducted in the desert near the U.S. Army’s Yuma Proving Ground. Additionally, the tests used only a 42,000 pound weighted tub as opposed to the 200,000 pound weight of the actual boosters. But the drop tests from 16,000 ft. from a C-17 airplane simulated the peak loads at parachute opening and measured the drag area to validate the design.

The parachute system will allow the Ares I and Ares V boosters to be recovered and then refurbished and reused for future flights. Ares I will launch the Orion vehicle, which will carry humans to the moon, while the larger Ares V will be used for the Cargo Launch Vehicle.

The boosters are scheduled to be flight tested in 2009.

Keep those tests coming!

Original News Source: NASA Press Release

True or False (Color): The Art of Extraterrestrial Photography

Carina Nebula. Image credit: Hubble Space Telescope/NASA.

When you look at the amazing pictures captured by the Hubble Space Telescope, or the Mars Exploration Rovers, do you ever wonder: is that what you’d really see with your own eyes? The answer, sadly, is probably not. In some cases, such as with the Mars rovers, scientists try and calibrate the rovers to see in “true color,” but mostly, colors are chosen to yield the most science. Here’s how scientists calibrate their amazing instruments, and the difference between true and false colors.

So, to start off, let’s put this in the form of a true or false question: T or F: When we see the gorgeous, iconic images from Hubble or the stunning panoramas from the Mars rovers, do those pictures represent what human eyes would see if they observed those vistas first hand?

Answer: For the Hubble, mostly false. For the rovers, mostly true, as the rovers provide a combination of so-called “true” and “false” color images. But, it turns out, the term “true color” is a bit controversial, and many involved in the field of extraterrestrial imaging are not very fond of it.

“We actually try to avoid the term ‘true color’ because nobody really knows precisely what the ‘truth’ is on Mars,” said Jim Bell, the lead scientist for the Pancam color imaging system on the Mars Exploration Rovers (MER). In fact, Bell pointed out, on Mars, as well as Earth, color changes all the time: whether it’s cloudy or clear, the sun is high or low, or if there are variations in how much dust is in the atmosphere. “Colors change from moment to moment. It’s a dynamic thing. We try not to draw the line that hard by saying ‘this is the truth!'”

Bell likes to use the term “approximate true color” because the MER panoramic camera images are estimates of what humans would see if they were on Mars. Other colleagues, Bell said, use “natural color.”

Zolt Levay of the Space Telescope Science Institute produces images from the Hubble Space Telescope. For the prepared Hubble images, Levay prefers the term “representative color.”

“The colors in Hubble images are neither ‘true’ colors nor ‘false’ colors, but usually are representative of the physical processes underlying the subjects of the images,” he said. “They are a way to represent in a single image as much information as possible that’s available in the data.”

True color would be an attempt to reproduce visually accurate color. False color, on the other hand, is an arbitrary selection of colors to represent some characteristic in the image, such as chemical composition, velocity, or distance. Additionally, by definition, any infrared or ultraviolet image would need to be represented with “false color” since those wavelengths are invisible to humans.

The cameras on Hubble and MER do not take color pictures, however. Color images from both spacecraft are assembled from separate black & white images taken through color filters. For one image, the spacecraft have to take three pictures, usually through a red, a green, and a blue filter and then each of those photos gets downlinked to Earth. They are then combined with software into a color image. This happens automatically inside off-the-shelf color cameras that we use here on Earth. But the MER Pancams have 8 different color filters while Hubble has almost 40, ranging from ultraviolet (“bluer” than our eyes can see,) through the visible spectrum, to infrared (“redder” than what is visible to humans.) This gives the imaging teams infinitely more flexibility and sometimes, artistic license. Depending on which filters are used, the color can be closer or farther from “reality.”

Stone mountain rock outcrop in true and false colour. Image credit: NASA/JPL
Stone mountain rock outcrop in true and false colour. Image credit: NASA/JPL

The same rock imaged in true and false color by Opportunity.

In the case of the Hubble, Levay explained, the images are further adjusted to boost contrast and tweak colors and brightness to emphasize certain features of the image or to make a more pleasing picture.

But when the MER Pancam team wants to produce an image that shows what a human standing on Mars would see, how do they get the right colors? The rovers both have a tool on board known as the MarsDial which has been used as an educational project about sundials. “But its real job is a calibration target,” said Bell. “It has grayscale rings on it with color chips in the corners. We measured them very accurately and took pictures of them before launch and so we know what the colors and different shades of grey are.”

One of the first pictures taken by the rovers was of the MarsDial. “We take a picture of the MarsDial and calibrate it and process it through our software,” said Bell. “If it comes out looking like we know it should, then we have great confidence in our ability to point the camera somewhere else, take a picture, do the same process and that those colors will be right, too.”

Hubble can also produce color-calibrated images. Its “UniverseDial” would be standard stars and lamps within the cameras whose brightness and color are known very accurately. However, Hubble’s mission is not to produce images that faithfully reproduce colors. “For one thing that is somewhat meaningless in the case of most of the images,” said Levay, “since we generally couldn’t see these objects anyway because they are so faint, and our eyes react differently to colors of very faint light.” But the most important goal of Hubble is produce images that convey as much scientific information as possible.

The rover Pancams do this as well. “It turns out there is a whole variety of iron-bearing minerals that have different color response at infrared wavelengths that the camera is sensitive to,” said Bell, “so we can make very garish, kind of Andy Warhol-like false color pictures.” Bell added that these images serve double duty in that they provide scientific information, plus the public really enjoys the images.

And so, in both Hubble and MER, color is used as a tool, to either enhance an object’s detail or to visualize what otherwise could not be seen by the human eye. Without false color, our eyes would never see (and we would never know) what ionized gases make up a nebula, for example, or what iron-bearing minerals lie on the surface of Mars.

As for “true color,” there’s a large academic and scholarly community that studies color in areas such as the paint industry that sometimes gets upset when the term “true color” is used by the astronomical imaging group, Bell explained.

“They have a well-established framework for what is true color, and how they quantify color,” he said. “But we’re not really working within that framework at that level. So we try to steer away from using the term ‘true color’.”

Levay noted that no color reproduction can be 100% accurate because of differences in technology between film and digital photography, printing techniques, or even different settings on a computer screen. Additionally, there are variations in how different people perceive color.

“What we’re doing on Mars is really just an estimate,” Bell said, “it’s our best guess using our knowledge of the cameras with the calibration target. But whether it is absolutely 100% true, I think it’s going to take people going there to find that out.”

For more information see http://hubblesite.org/ or check out Jim Bell’s 2006 book “Postcards From Mars.”

A Submarine for Europa

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Many planetary scientists believe that Jupiter’s moon Europa is our solar system’s best contender to share Earth’s distinction of harboring life. Evidence gathered by the Voyager and Galileo spacecrafts suggests Europa contains a deep, possibly warm ocean of salty water under an outer shell of fissured ice. In a paper published in the July 2007 Journal of Aerospace Engineering a British mechanical engineer proposes sending a submarine to explore Europa’s oceans.

Carl T. F. Ross, a professor at the University of Portsmouth in England offers an abstract design of an underwater craft built of a metal matrix composite. He also provides suggestions for suitable power supplies, communication techniques and propulsion systems for such a vessel in his paper, “Conceptual Design of a Submarine to Explore Europa’s Oceans.”

Ross’s paper weighs the options for constructing a submarine capable of withstanding the undoubtedly high pressure within Europa’s deep oceans. Scientists believe that this moon’s oceans could be up to 100 kilometers deep, more than ten times deeper than Earth’s oceans. Ross proposes a 3 meter long cylindrical sub with an internal diameter of 1 meter. He believes that steel or titanium, while strong enough to withstand the hydrostatic pressure, would be unsuitable as the vessel would have no reserve buoyancy. Therefore, the sub would sink like a rock to the bottom of the ocean. A metal matrix or ceramic composite would offer the best combination of strength and buoyancy.

Ross favors a fuel cell for power, which will be needed for propulsion, communications and scientific equipment, but notes that technological advances in the ensuing years may provide better sources for power.

Ross concedes that a submarine mission to Europa won’t occur for at least 15-20 years. Planetary scientist William B. McKinnon agrees.
Artist illustration of a Europa probe. Image credit: NASA/JPL
“It is difficult enough, and expensive, to get back to Europa with an orbiter, much less imagine a landing or an ocean entry,” said McKinnon, professor of Earth and Planetary Sciences at Washington University in St. Louis, Missouri. “Sometime in the future, and after we have determined the ice shell thickness, we can begin to seriously address the engineering challenges. For now, it might be best to search for those places where the ocean has come to us. That is, sites of recent eruptions on Europa’s surface, whose compositions can be determined from orbit.”

The Jet Propulsion Laboratory is currently working on a concept called the Europa Explorer which would deliver a low orbit spacecraft to determine the presence (or absence) of a liquid water ocean under Europa’s ice surface. It would also map the distribution of compounds of interest for pre-biotic chemistry, and characterize the surface and subsurface for future exploration. “This type of mission,” says McKinnon, “would really allow us to get the hard proof we would all like that the ocean is really there, and determine the thickness of the ice shell and find thin spots if they exist.”

McKinnon added that an orbiter could find “hot spots” that indicate recent geological or even volcanic activity and obtain high-resolution images of the surface. The latter would be needed to plan any successful landing.

Slightly smaller than Earth’s moon, Europa has an exterior that is nearly craterless, meaning a relatively “young” surface. Data from the Galileo spacecraft shows evidence of near-surface melting and movements of large blocks of icy crust, similar to ice bergs or ice rafts on Earth.

While Europa’s midday surface temperatures hover around 130 K (-142 C, -225 degrees F), interior temperatures could be warm enough for liquid water to exist underneath the ice crust. This internal warmth comes from tidal heating caused by the gravitational forces of Jupiter and Jupiter’s other moons which pull Europa’s interior in different directions. Scientists believe similar tidal heating drives the volcanoes on another Jovian moon, Io. Seafloor hydrothermal vents have also been suggested as another possible energy source on Europa. On Earth, undersea volcanoes and hydrothermal vents create environments that sustain colonies of microbes. If similar systems are active on Europa, scientists reason that life might be present there too.

Among scientists there is a big push to get a mission to Europa underway. However this type of mission is competing for funding against NASA’s goal of returning to our own moon with human missions. The proposed Jupiter Icy Moon Orbiter (JIMO) a nuclear powered mission to study three of Jupiter’s moons, fell victim to cuts in science missions in NASA’s Fiscal Year 2007 Budget.

Ross has been designing and improving submarines for over 40 years, but this is the first time he’s designed a craft for use anywhere but on Earth.

“The biggest problem that I see with the robot submarine is being able to drill or melt its way through a maximum of 6 km of the ice, which is covering the surface,” said Ross. “However, the ice may be much thinner in some places. It may be that we will require a nuclear pressurized water reactor on board the robot submarine to give us the necessary power and energy to achieve this”

While Ross proposes using parachutes to bring the submarine to Europa’s surface, McKinnon points out that parachutes would not work in Europa’s almost airless atmosphere.

Ross has received very positive responses to his paper from friends and colleagues, he says, including notable British astronomer Sir Patrick Moore. Ross says his life has revolved around submarines since 1959 and he finds this new concept of a submarine on Europa to be very exciting.

McKinnon classifies the exploration of Europa as “extremely important.”

“Europa is a place is where we are pretty sure we have abundant liquid water, energy sources, and biogenic elements such as carbon, nitrogen, sulfur, phosphorus, etc,” he said. “Is there life, any kind of life, in Europa’s ocean? Questions don’t get much more profound.”

Written by Nancy Atkinson

The Mars Landing Approach: Getting Large Payloads to the Surface of the Red Planet

The first true-colour image of Mars from ESA’s Rosetta generated using the OSIRIS orange (red), green and blue colour filters. The image was acquired on 24 February 2007 at 19:28 CET from a distance of about 240 000 km. Credit: MPS for OSIRIS Team MPS/UPD/LAM/ IAA/ RSSD/ INTA/ UPM/ DASP/ IDA

Some proponents of human missions to Mars say we have the technology today to send people to the Red Planet. But do we? Rob Manning of the Jet Propulsion Laboratory discusses the intricacies of entry, descent and landing and what needs to be done to make humans on Mars a reality.

There’s no comfort in the statistics for missions to Mars. To date over 60% of the missions have failed. The scientists and engineers of these undertakings use phrases like “Six Minutes of Terror,” and “The Great Galactic Ghoul” to illustrate their experiences, evidence of the anxiety that’s evoked by sending a robotic spacecraft to Mars — even among those who have devoted their careers to the task. But mention sending a human mission to land on the Red Planet, with payloads several factors larger than an unmanned spacecraft and the trepidation among that same group grows even larger. Why?

Nobody knows how to do it.

Surprised? Most people are, says Rob Manning the Chief Engineer for the Mars Exploration Directorate and presently the only person who has led teams to land three robotic spacecraft successfully on the surface of Mars.

“It turns out that most people aren’t aware of this problem and very few have worried about the details of how you get something very heavy safely to the surface of Mars,” said Manning.

He believes many people immediately come to the conclusion that landing humans on Mars should be easy. After all, humans have landed successfully on the Moon and we can land our human-carrying vehicles from space to Earth. And since Mars falls between the Earth and the Moon in size, and also in the amount of atmosphere it has then the middle ground of Mars should be easy. “There’s the mindset that we should just be able to connect the dots in between,” said Manning.

But as of now, the dots will need to connect across a large abyss.

“We know what the problems are. I like to blame the god of war,” quipped Manning. “This planet is not friendly or conducive for landing.”

The real problem is the combination of Mars’ atmosphere and the size of spacecraft needed for human missions. So far, our robotic spacecraft have been small enough to enable at least some success in reaching the surface safely. But while the Apollo lunar lander weighed approximately 10 metric tons, a human mission to Mars will require three to six times that mass, given the restraints of staying on the planet for a year. Landing a payload that heavy on Mars is currently impossible, using our existing capabilities. “There’s too much atmosphere on Mars to land heavy vehicles like we do on the moon, using propulsive technology completely,” said Manning, “and there’s too little atmosphere to land like we do on Earth. So, it’s in this ugly, grey zone.”

But what about airbags, parachutes, or thrusters that have been used on the previous successful robotic Mars missions, or a lifting body vehicle similar to the space shuttle?

None of those will work, either on their own or in combination, to land payloads of one metric ton and beyond on Mars. This problem affects not only human missions to the Red Planet, but also larger robotic missions such as a sample return. “Unfortunately, that’s where we are,” said Manning. “Until we come up with a whole new trick, a whole new system, landing humans on Mars will be an ugly and scary proposition.”

Road Mapping
In 2004 NASA organized a Road Mapping session to discuss the current capabilities and future problems of landing humans on Mars. Manning co-chaired this event along with Apollo 17 astronaut Harrison Schmitt and Claude Graves, who has since passed away, from the Johnson Space Center. Approximately 50 other people from across NASA, academia and industry attended the session. “At that time the ability to explain these problems in a coherent way was not as good,” said Manning. “The entry, descent and landing process is actually made up of people from many different disciplines. Very few people really understood, especially for large scale systems, what all of the issues were. At the Road Mapping session we were able to put them all down and talk about them.”

The major conclusion that came from the session was that no one has yet figured out how to safely get large masses from speeds of entry and orbit down to the surface of Mars. “We call it the Supersonic Transition Problem,” said Manning. “Unique to Mars, there is a velocity-altitude gap below Mach 5. The gap is between the delivery capability of large entry systems at Mars and the capability of super-and sub-sonic decelerator technologies to get below the speed of sound.”

Plainly put, with our current capabilities, a large, heavy vehicle, streaking through Mars’ thin, volatile atmosphere only has about ninety seconds to slow from Mach 5 to under Mach 1, change and re-orient itself from a being a spacecraft to a lander, deploy parachutes to slow down further, then use thrusters to translate to the landing site and finally, gently touch down.

No Airbags
When this problem is first presented to people, the most offered solution, Manning says, is to use airbags, since they have been so successful for the missions that he has been involved with; the Pathfinder rover, Sojourner and the two Mars Exploration Rovers (MER), Spirit and Opportunity.

But engineers feel they have reached the capacity of airbags with MER. “It’s not just the mass or the volume of the airbags, or the size of the airbags themselves, but it’s the mass of the beast inside the airbags,” Manning said. “This is about as big as we can take that particular design.”

In addition, an airbag landing subjects the payload to forces between 10-20 G’s. While robots can withstand such force, humans can’t. This doesn’t mean airbags will never be used again, only that airbag landings can’t be used for something human or heavy.

Even the 2009 Mars Science Laboratory (MSL) rover, weighing 775 kilograms (versus MER at 175.4 kilograms each) requires an entirely new landing architecture. Too massive for airbags, the small-car sized rover will use a landing system dubbed the Sky Crane. “Even though some people laugh when they first see it, my personal view is that the Sky Crane is actually the most elegant system we’ve come up with yet, and the simplest,” said Manning. MSL will use a combination of a rocket-guided entry with a heat shield, a parachute, then thrusters to slow the vehicle even more, followed by a crane-like system that lowers the rover on a cable for a soft landing directly on its wheels. Depending on the success of the Sky Crane with MSL, it’s likely that this system can be scaled for larger payloads, but probably not the size needed to land humans on Mars.

Atmospheric Anxiety and Parachute Problems
“The great thing about Earth,” said Manning “is the atmosphere.” Returning to Earth and entering the atmosphere at speeds between 7-10 kilometers per second, the space shuttle, Apollo and Soyuz capsules and the proposed Crew Exploration Vehicle (CEV) will all decelerate to less than Mach 1 at about twenty kilometers above the ground just by skimming through Earth’s luxuriously thick atmosphere and using a heat shield. To reach slower speeds needed for landing, either a parachute is deployed, or in the case of the space shuttle, drag and lift allow the remainder of the speed to bleed away.

But Mars’ atmosphere is only one per cent as dense as Earth’s. For comparison, Mars atmosphere at its thickest is equivalent to Earth’s atmosphere at about 35 kilometers above the surface The air is so thin that a heavy vehicle like a CEV will basically plummet to the surface; there’s not enough air resistance to slow it down sufficiently. Parachutes can only be opened at speeds less than Mach 2, and a heavy spacecraft on Mars would never go that slow by using just a heat shield. “And there are no parachutes that you could use to slow this vehicle down,” said Manning. “That’s it. You can’t land a CEV on Mars unless you don’t mind it being a crater on the surface.”

That’s not good news for the Vision for Space Exploration. Would a higher lift vehicle like the space shuttle save the day? “Well, on Mars, when you use a very high lift to weight to drag ratio like the shuttle,” said Manning, “in order to get good deceleration and use the lift properly, you’d need to cut low into the atmosphere. You’d still be going at Mach 2 or 3 fairly close to the ground. If you had a good control system you could spread out your deceleration to lengthen the time you are in the air. You’d eventually slow down to under Mach 2 to open a parachute, but you’d be too close to the ground and even an ultra large supersonic parachute would not save you.”

Supersonic parachute experts have concluded that to sufficiently slow a large shuttle-type vehicle on Mars and reach the ground at reasonable speeds would require a parachute one hundred meters in diameter.

“That’s a good fraction of the Rose Bowl. That’s huge,” said Manning. “We believe there’s no way to make a 100-meter parachute that can be opened safely supersonically, not to mention the time it takes to inflate something that large. You’d be on the ground before it was fully inflated. It would not be a good outcome.”

Heat Shields and Thrusters

It’s not that Mars’ atmosphere is useless. Manning explained that with robotic spacecraft, 99% of the kinetic energy of an incoming vehicle is taken away using a heat shield in the atmosphere. “It’s not inconceivable that we can design larger, lighter heat shields,” he said, “but the problem is that right now the heat shield diameter for a human-capable spacecraft overwhelms any possibility of launching that vehicle from Earth.” Manning added that it would almost be better if Mars were like the moon, with no atmosphere at all.

If that were the case, an Apollo-type lunar lander with thrusters could be used. “But that would cause another problem,” said Manning, “in that for every kilogram of stuff in orbit, it takes twice as much fuel to get to the surface of Mars as the moon. Everything is twice as bad since Mars is about twice as big as the moon.” That would entail a large amount of fuel, perhaps over 6 times the payload mass in fuel, to get human-sized payloads to the surface, all of which would have to be brought along from Earth. Even on a fictitious air-less Mars that is not an option.

But using current thruster technology in Mars’ real, existing atmosphere poses aerodynamic problems. “Rocket plumes are notoriously unstable, dynamic, chaotic systems,” said Manning. “Basically flying into the plume at supersonics speeds, the rocket plume is acting like a nose cone; a nose cone that’s moving around in front of you against very high dynamic pressure. Even though the atmospheric density is very low, because the velocity is so high, the forces are really huge.”

Manning likened theses forces to a Category Five hurricane. This would cause extreme stress, with shaking and twisting that would likely destroy the vehicle. Therefore using propulsive technology alone is not an option.

Using thrusters in combination with a heat shield and parachute also poses challenges. Assuming the vehicle has used some technique to slow to under Mach 1, using propulsion just in last stages of descent to gradually adjust the lander’s trajectory would enable the vehicle to arrive very precisely at the desired landing site. “We’re looking at firing thrusters less than 1 kilometer above the ground. Your parachute has been discarded, and you see that you are perhaps 5 kilometers south of where you want to land,” said Manning. “So now you need the ability to turn the vehicle over sideways to try to get to your landing spot. But this may be an expensive option, adding a large tax in fuel to get to the desired landing rendezvous point.”

Additionally, on the moon, with no atmosphere or weather, there is nothing pushing against the vehicle, taking it off target, and a la Neil Armstrong on Apollo 11, the pilot can “fly out the uncertainties” as Manning called it, to reach a suitable or desired landing site. On Mars, however, the large variations in the density of the atmosphere coupled with high and unpredictable winds conspire to push vehicles off course. “We need to have ways to fight those forces or ways to make up for any mis-targeting using the propulsion system,” said Manning. “Right now, we don’t have that ability and we’re a long way from making it happen.”

Supersonic Decelerators

The best hope on the horizon for making the human enterprise on Mars possible is a new type of supersonic decelerator that’s only on the drawing board. A few companies are developing a new inflatable supersonic decelerator called a Hypercone.

Imagine a huge donut with a skin across its surface that girdles the vehicle and inflates very quickly with gas rockets (like air bags) to create a conical shape. This would inflate about 10 kilometers above the ground while the vehicle is traveling at Mach 4 or 5, after peak heating. The Hypercone would act as an aerodynamic anchor to slow the vehicle to Mach 1.

Glen Brown, Chief Engineer at Vertigo, Inc. in Lake Elsinore, California was also a participant in the Mars Road Mapping session. Brown says Vertigo has been doing extensive analysis of the Hypercone, including sizing and mass estimates for landers from four to sixty metric tons. “A high pressure inflatable structure in the form a of a torus is a logical way to support a membrane in a conical shape, which is stable and has high drag at high Mach numbers,” Brown said, adding that the structure would likely be made of a coated fabric such as silicon-Vectran matrix materials. Vertigo is currently competing for funding from NASA for further research, as the next step, deployment in a supersonic wind tunnel, is quite expensive.

The structure would need to be about thirty to forty meters in diameter. The problem here is that large, flexible structures are notoriously difficult to control. At this point in time there are also several other unknowns of developing and using a Hypercone.

One train of thought is that if the Hypercone can get the vehicle under Mach 1, then subsonic parachutes could be used, much like the ones employed by Apollo, or that the CEV is projected to use to land on Earth. However, it takes time for the parachutes to inflate, and subsequently there would only be a matter of seconds of use, allowing time to shed the parachutes before converting to a propulsive system.

“You’d also need to use thrusters,” said Manning. “You’re falling 10 times faster because the density of Mars’ atmosphere is 100 times less than Earth’s. That means that you can’t just land with parachutes and touch the ground. You’d break people’s bones, if not the hardware. So you need to transition from a parachute system to an Apollo-like lunar legged lander sometime before you get to the ground.”

Manning believes that those who are immersed in these matters, like himself, see the various problems fighting each other. “It’s hard to get your brain around all these problems because all the pieces connect in complex ways,” he said. “It’s very hard to see the right answer in your mind’s eye.”

The additional issues of creating new lightweight but strong shapes and structures, with the ability to come apart and transform from one stage to another at just the right time means developing a rapid-fire Rube Goldberg-like contraption.

“The honest truth of the matter,” said Manning, “is that we don’t have a standard canonical form, a standard configuration of systems that allows us to get to the ground, with the right size that balances the forces, the loads, the people, and allows us to do all the transformation that needs to be done in the very small amount of time that we have to land.”

Other Options and Issues

Another alternative discussed at the 2004 Mars Road Mapping session was the space elevator.

“Mars is really begging for a space elevator,” said Manning. “I think it has great potential. That would solve a lot of problems, and Mars would be an excellent platform to try it.” But Manning admitted that the technology needed to suspend a space elevator has not yet been invented. The issues with space elevator technology may be vast, even compared with the challenges of landing.

Despite these known obstacles, there are few at NASA currently spending any quality time working on any of the issues of landing humans on Mars.

Manning explained, “NASA does not yet have the resources to solve this problem and also develop the CEV, complete the International Space Station and do the lunar landing systems development at the same time. But NASA knows that this is on its plate of things to do in the future and is just beginning to get a handle on the needed technology developments. I try to go out of my way to tell this story because I’m encouraging young aeronautical engineering students, particularly graduate students, to start working on this problem on their own. There is no doubt in my mind that with their help, we can figure out how to make reliable human-scale landing systems work on Mars.”

While there is much interest throughout NASA and the space sector to try to tackle these issues in the ensuing years, technology also needs a few more years to catch up to our dreams of landing humans on Mars.

And this story, like all good engineering stories, will inevitably read like a good detective novel with technical twist and turns, scientific intrigue, and high adventure on another world.

STS-115 Brings More Power to the Station

STS-115 is an ambitious mission that returns the focus of human spaceflight to building the International Space Station, bringing new capabilities to the ISS. While a song by John Lennon asserts that revolution will bring power to the people, it will be a new set of solar arrays and its ability for rotation that will provide more power to the space station.
Continue reading “STS-115 Brings More Power to the Station”

The NASA Science Missions Getting Cut

Artist illustration of the Dawn mission, now cancelled. Image credit: NASA/JPL. Click to enlarge.
With the release NASA’s 2007 budget request, it was clear that the productive science programs will be paying the price for the new Vision for Space Exploration, returning humans to the Moon and then sending them on to Mars. Many programs will be affected. We review the missions, what they were supposed to accomplish, and what the cuts will bring. It’s not a pretty picture.

Scientists, space interest groups, and even members of Congress have expressed so much concern about NASA’s $16.79 billion budget request for Fiscal Year 2007 that the Associate Administrator of NASA’s Science Directorate has reportedly agreed to review the proposed cuts in science and solar system exploration programs. According to the American Association for the Advancement of Science and their magazine Science, NASA will re-evaluate the missions and programs that are under threat of being cancelled or delayed.

The outcry over the budget proposal began immediately after it was released on February 6. At first glance, the 2007 budget would be an overall increase of 3.2% over the FY06 appropriation, or a 1.5% increase when including Katrina funding in Fiscal Year 2006. But while the proposed budget will support the space shuttle and space stations programs in addition to the emerging costs of the Vision for Space Exploration, it does so while slashing the funds needed to sustain the current and anticipated programs in science and exploration.

Central to the problems of this budget is that the space shuttle program has a projected $3 – 5 billion shortfall for the planned 17 missions before the shuttle is to be retired in approximately 2010. To alleviate that shortage, NASA is planning to shift $3 billion from planetary exploration and science over the next four years to pay for the manned missions.

The Planetary Society has said that what NASA is doing is essentially transferring funds from a popular and highly productive program (science) to one that is scheduled for termination (the space shuttle).

“I am extremely uneasy about this budget,” said U.S. House Science Committee Chairman Sherwood Boehlert from New York. “This budget is bad for space science, worse for earth science, perhaps worse still for aeronautics. It basically cuts or deemphasizes every forward looking, truly futuristic program of the agency to fund operational and development programs to enable us to do what we are already doing or have done before.”

Senator Pete Domenici from New Mexico and 59 other senators have introduced a bill to authorize a 10 percent increase per year in NASA’s science budget from now through 2013.

But Louis Friedman, Executive Director of the Planetary Society doesn’t anticipate any big changes in what Congress will approve for NASA. “I think it is unlikely that NASA will get very much of an increase in budget, but I do anticipate some give and take and perhaps some restoration of science funding,” he said. “We will be trying very hard for a major restoration of funding, but it will be a difficult fight.”

The budget shows a 1.5% increase in science funding for this year, and 1% increase for each of the following two years, before inflation is taken into consideration. But even with that increase, there will actually be $2 billion less for space science and $1.5 billion less for exploration that what was previously planned, and needed, for all of the missions to continue.

Following are some of the areas that would be affected:
– Research and analysis: 15% across-the-board cuts in grants for research, ($350 to $400 million over the next five years) with some retroactive to 2006. An official at NASA Headquarters said he wasn’t aware that any notices of specific research cuts have been issued at this time.
– Astrobiology research alone will have 50% of funding slashed.
– Astronomy and astrophysics at NASA cut by 20% over 5 years
– Aeronautics: cut by 18.1%, down to $724.4 million

In a press conference, NASA Administrator Mike Griffin acknowledged that “science and exploration are each paying to help complete our pre-existing obligations to the space station and the space shuttle, and when those obligations are completed the other major pieces of our portfolio will be able to do better.” In his congressional testimony, Griffin said, “I truly wish that it could be otherwise, but there is only so much money.”

NASA has 50 science and planetary missions currently operating, which includes missions from Voyager to the all of the Earth orbiting satellites to the recently launched New Horizons mission to Pluto. There are 22 missions that are in development, and 19 being studied for development. The budget maintains all of these missions, with the exception of some delays in launches to upgrade or replace existing Earth orbiting satellites. Following are missions that, if the current budget proposal is approved, will be cancelled or delayed:

Dawn: Cancelled.
The mission: Using an ion engine, the spacecraft would have traveled to the asteroid belt to study two dissimilar asteroids to help determine the role that size and water play in planetary evolution. It also would have helped determine the origin and evolution of our solar system. According to the NASA Watch website, 98% of Dawn’s hardware is complete, with a majority of it already integrated into the spacecraft. The shutdown costs for Dawn are $10 million, while it would take $40 million to complete the spacecraft and fly the mission.

In a statement, JPL Director Dr. Charles Elachi said, “During development a number of implementation and technical challenges led to a cost increase estimate of approximately 20% (from $373.2M to $446.5M.) Even though all the technical issues could be resolved, additional funding is still needed to complete and launch the mission by the spring of 2007. Of course we are disappointed, but the current tight budget environment has led to its cancellation.”

NASA has defended the cancellation not as a budget cut, but as a management decision due to developmental problems with the project. Louis Friedman says, “Indeed, (Dawn’s) cancellation was made separate from the budget submission and is not addressed in the Fiscal Year 2007 budget proposal. But the timing of the cancellation is suspicious – made immediately after the budget hearing in which testimony was unanimous that making mission cancellations in order to beef up research an analysis funding was an acceptable allocation of priorities.”

SOFIA (Stratospheric Observatory for Infrared Astronomy): Cancelled.
The mission: An airborne observatory consisting of a 2.5 meter reflecting infrared telescope. It would facilitate in developing observational techniques, new instrumentations, and in education of young scientists and teachers. The telescope is fully installed in a 747 aircraft and is functional. The first test flights for the observatory would have been done this year. SOFIA was being conducted in cooperation with the DLR, the German Aerospace Center, and was part of NASA’s Origins Program.

Mission to Europa: Cancelled.
Friedman said that the Europa mission was not yet an approved mission, but preliminary work had started and Congress had directed NASA to do that work in anticipation of a Fiscal Year 2007 new start for this mission. Instead NASA cancelled the existing work and ignored the request for a FY ’07 new start.

Last year, the Jupiter Icy Moon Orbiter was put down, which would have used a nuclear reactor to power an ion engine to send an orbiter to 3 of Jupiter’s moons. This year future missions to Europa have been tabled, even though the National Academy of Sciences and internal NASA advisory committees have endorsed the exploration of Europa as the next highest priority solar system objective after Mars.

Terrestrial Planet Finder: Cancelled.
The proposed mission: Terrestrial Planet Finder would have consisted of two complementary observatories: a visible-light coronagraph and a formation-flying infrared interferometer. It would study extra-solar planets, from their formation and development in disks of dust and gas around newly forming stars to studying features of planets and determining suitability for containing life.

TPF was not yet an approved mission, but preliminary development work had begun. NASA cancelled that work and removed TPF from the list of missions to be started in the next four years.

SIM Planet Quest: Delayed.
Formerly called the Space Interferometry Mission. As an optical interferometer in an Earth-trailing orbit, the spacecraft would survey approximately 100 of our closest stars and identify potential habitable planets. It would also survey thousands of other stars to help our general understanding of the formation and evolution of planetary systems. Also would help to answer questions in astrophysics concerning dark matter, black holes and the mass of the universe.

Mars Sample Return Mission: Delayed Indefinitely.
Not yet an approved mission, but preliminary development had begun. An exciting if not controversial mission to bring Martian soil to Earth.

Additional Programs Affected
Two Mars Scout missions planned for after 2011 were removed from the four year planning budget. These missions may have included airborne vehicles such as airplanes or balloons and small landers.

The Explorer Program, which launches small spacecraft to study areas such as Heliophysics and Astrophysics would be cut drastically with the earliest launch coming in 2014.

Beyond Einstein would be delayed indefinitely. These are missions such as Constellation -X and LISA that would attempt to answer questions about the Big Bang, Black Holes and Dark Matter.

The Associated Press has reported that a long list of satellites orbiting Earth are under threat of being delayed, downsized or cancelled. Scientists have warned that decreasing funding for these satellites will jeopardize the capability for forecasting weather and monitoring environmental issues.
The list includes:

Landsat: delay in launch of satellite to replace and upgrade Landsat 7, launched in 1999.

Earth Observing System: If cut, satellites such as Aqua (2002) and Terra (1999) would not be replaced when they fail.

Global Precipitation Measuring Mission: The launch of GPMM has been pushed back to 2012. GPMM will replace and upgrade the Tropical Rainfall Measuring Mission, which was supposed to be decommissioned in 2004.

Deep Space Climate Observatory: cancelled. An Earth observing satellite placed at the L-1 Point to determine cloud and radiation properties of the atmosphere. The spacecraft is already built, but would cost $60-100 million to launch and operate.

National Polar-Orbiting Operational Environmental Satellite System: Under review. Will monitor global environmental conditions, and collect and disseminate data related to weather, atmosphere, oceans and land, and is a cooperative effort between NASA, NOAA, the Department of Defense and the Department of Commerce.

The next round of Congressional hearings on the budget proposal are scheduled for March 30 at the House Appropriation Subcommittee on Science, State Justice and Commerce Hearing.

Written by Nancy Atkinson

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