Volume 14, Number 5 September/October 2002
Odyssey Unveils Vast Subterranean Ice Ocean on Mars
The latest findings from the newest visitor to the Red Planet, NASAs Mars Odyssey spacecraft, confirm that Mars dry exterior may hide vast underground ice oceans. For many years scientists have speculated that near-surface water existed on the Red Planet. Now, measurements by Odysseys gamma-ray and neutron spectrometers, which detect the hydrogen present in water ice, have confirmed initial estimates showing enormous quantities of buried treasure lying just beneath the surface of Mars enough ice to fill Lake Michigan twice over. This is really amazing, said William Boynton, principal investigator for Odysseys gamma ray spectrometer suite. This is the best direct evidence we have of subsurface water ice on Mars. We were hopeful that we could find evidence of ice, but what we have found is much more ice than we ever expected.
The ice probably accounts for just a few percent by mass of the surface of Mars, but covers a vast area that stretches from the frozen southern polar cap northward to about 60 degrees south latitude. And that may be just the tip of the iceberg. Researchers suspect the same subsurface deposits exist in the northern hemisphere, but cannot confirm it until later this year due to the Martian winter. The signature of buried hydrogen seen in the south polar area is also seen in the north, but not in the areas close to the pole, said William Feldman, principal investigator for the neutron spectrometer. This is because the seasonal carbon dioxide (dry ice) frost covers the polar areas in winter. As northern spring approaches, the latest neutron data indicate that the frost is receding, revealing hydrogen-rich soil below.
The artesian deposits are believed to consist of ice mixed with dirt, dust and rock that form the top one-meter of the planets surface. The ice-rich layer is about 60 centimeters beneath the surface at 60 degrees south latitude, and approaches within about 30 centimeters of the surface at 75 degrees south latitude. However, a porous layer of rocky rubble more than a kilometer thick could trap still more water ice particularly in the polar regions.
The Mars Polar Lander was slated to touch down in exactly the right spot to discover the ice deposits, but the ill-fated probe crashed into the icy terrain in December 1999. Several new landers will visit Mars over next few yearsNASAs twin Mars rovers and ESAs Beagle 2but none are targeted at the region where ice may exist. However, the dramatic discovery of subsurface ice may guide the selection of future landing and exploration sites on Mars, and may suggest areas to look for evidence of past life.
The discovery of potentially vast deposits of water ice close to the surface on Mars could also breath new life into plans to send humans to explore the Red Planet. Artesian ice deposits close to the surface could provide water for life support and hygiene for astronauts plus serve as the raw materials for rocket fuel. Simple solar-powered techniques could break water down into hydrogen and oxygen. Astronauts could breathe the oxygen and the hydrogen could be used for rocket propellant or combined with carbon from Mars atmosphere to form methane, another potential rocket fuel. In the wake of the icy discovery, Russian space officials have proposed an ambitious project to send a six-person team to Mars by the year 2015.
NASA Gets to Bottom of Europan Ocean
New results from NASAs aging Galileo spacecraft suggest that getting to the bottom of any ocean on Jupiters moon Europa will be no easy task. Images snapped by Galileo during flybys of the Jovian moon indicate that the crust of ice covering the putative liquid ocean is at least 19 kilometers thickmuch too dense for any lander to burrow through to find what lies beneath.
Scientists have ranked Europa along with Mars as a place where life, past or present, might exist in the stygian depths. But if the new estimates for the ice crust hold, plans to drill through the ice and look for life may have hit an iceberg. It raises challenges for future planning but it doesnt end the debate over whether there is life on Europa. It still requires us to go there, said Paul Schenk of the Lunar and Planetary Institute.
Although the dense crust poses a challenge, the thickness of the shell of ice does not rule out Europan marine life. Organisms survive at the bottom of the Earths oceans without sunlight, using chemical energy. We know that life can evolve into almost any niche in the environment, said Schenk. What we dont know is where it starts. Could it have started at the bottom of the ocean on Europa? We dont know. If it did, then it would be perfectly happy there right now, he added. The key to cracking the puzzlealong with the iceis to find the right landing site, which will require reconnaissance missions before sending a lander to the Europan surface.
Newfound Planetary System Has Hometown Look
Astronomers have discovered a planetary system around another star that is similar in scale to our solar system. After 15 years of observation, the worlds premier planet-hunting team has finally found a planetary system that has a hometown look. Astronomers had found Jupiter-like planets around other stars before. But they were all very close to their parent suns (hot Jupiters) and their orbits were eccentricnot circular. The newfound planet orbits the star 55 Cancri at 5.5 AU, comparable to Jupiters distance from our Sun, and its slightly elongated orbit takes it around the star in about 13 years, which is similar to Jupiters orbital period.
The same star system, located in the constellation Cancer, was already known to have one planet, but that gas giant whipped around 55 Cancri in just 14.6 days at a distance of only 0.1 AU. All other extrasolar planets discovered up to now orbit closer to the parent star, and most of them have had elongated, eccentric orbits, said Geoffrey Marcy, co-discoverer of the Jupiter-like planet. But the new planet orbits as far from its star as our own Jupiter orbits the Sun.
A detailed look at the observations suggests that there may be more objects orbiting 55 Cancri because the two known planets do not explain all the data. One possible explanation is a Saturn-mass planet orbiting the star, but detailed calculations show that an Earth-sized planet could also survive in a stable orbit between the two gas giants. Spotting Earth-like planets is a stated goal of NASAs Origins Program. The existence of analogs to our solar system adds urgency to missions capable of detecting Earth-sized planetsfirst, the Space Interferometry Mission and then the Terrestrial Planet Finder, said Charles Beichman, the chief scientist of the Origins Program.
Too Close for Comfort
The Earth has been in the cosmic crosshairs of asteroids and comets for eons, and just missed a close encounter of the worst kind last summer. An asteroid about the size of a football field made one of the closest known approaches to Earth on June 14, zooming by just 119,229 kilometers away, less than a third of the distance to the Moon. It is only the sixth time an asteroid has been seen to penetrate the Moons orbit, and this fellow traveler was by far the biggest space rock to do so. What worried some astronomers, though, is that the object was only detected several days after its near miss. Astronomers from the Royal Observatory in Edinburgh later calculated the orbit of the asteroid and concluded that it came out of the Sun and was impossible to detect until one hour after skimming by the Earth.
The space rock only had a diameter of 50-120 meters, which is quite small by asteroid standards, but was traveling at over 10 kilometers a second. An impact from such a body would have caused local devastation similar to that which occurred in Tunguska, Siberia, in 1908, when 2,000 square kilometers of forest were flattened. Our ever increasing observational capacity is now detecting these close shaves from small objects, said Benny Peiser, of Liverpool John Moores University, UK. The probability is actually quite high that a Tunguska-sized object will hit us in our lifetimes, he added.
Astronomers Find Foul Weather on Brown Dwarfs
For the first time, researchers have observed planet-like weather influencing objects outside our solar system. A team of scientists from NASA and UCLA has found cloudy, stormy atmospheres on brown dwarfsobjects that are less massive than stars but have more bulk than giant planets like Jupiter. The best analogy to what we witness on these objects are the storm patterns on Jupiter, said Adam Burgasser, an astronomer at UCLA. But I suspect the weather on these more massive brown dwarfs makes the Great Red Spot look like a small squall.
Astronomers expected brown dwarfs, like most objects in the universe, to grow steadily fainter as they cool. However, some brown dwarfs brighten briefly as they cool down because of their bizarre weather patterns. While most astronomers consider brown dwarfs to be failed stars at best, they are still hot enough for iron and silicates to vaporize. But, as the brown dwarfs cool, these gases condense to form clouds. When the clouds are whisked away by storms, bright infrared light from the hotter atmosphere beneath the clouds escapes, accounting for the unusual brightening of the brown dwarfs.
The model matches the characteristics of a very broad range of brown dwarfs, but only if cloud clearing is considered, said Burgasser. While many groups have hinted that cloud structures and weather phenomena should be present, we believe we have actually shown that weather is present and can be quite dramatic.
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by Taylor Dinerman
Condi Rice is, without doubt, one of the two or three best qualified foreign policy experts in America. She speaks fluent Russian and German, and can handle herself pretty well in French. Her understanding of Euro-pean and Eurasian geopolitics is unmatched by anyone in her position in more than three decades. While she is a relative newcomer to the swamps of Middle East policy, so far, she, and the administration she serves, have done pretty wellor at least it looks that way from here.
Recently, she has been handed the role of revising Americas National Space Policy, beginning with those parts that deal with space transportation and remote sensing. As the head of the National Security Council, she naturally understands the importance of Space Activities for U.S. military operations and for the Intelligence community. How-ever, she has now been handed the job of reconciling all the varied groups and institutions who are affected by Space Policy. She will soon understand the very difficult strategic , scientific and political context in which she will have to work. She will have to consider more than just new rockets and satellites.
Keeping NASA and the Pentagon working more or less together while satisfying the Planetary Society and its Off To Pluto campaign, and those who want a space-based missile defense, as well as those, like Congressman Nick Lampson (D-TX), who want NASA to follow the Presidents fathers goals, Back to the Moon and on to Mars, is probably impossible. The review will be shaped by the constraints of OMBs planned budgets, and by projections and estimates of how much or how little the economy will grow over the next ten years. These plans and projections will be heavily revised by Congressional actions. This will happen no matter which party controls the House and Senate.
As part of the review, she may want to consider adding a section on unfunded priorities, just like the military services do when they want to give their congressional allies guidance on what they would ask for if their budget plans allowed them to. There are always ideas and missions that NASA would like to pursue if only it had the money.
This puts the question of how and when to replace NASAs Space Shuttle right in her lap. Her recommendations to the President will not only shape Americas ability to access space for the next couple of decades, but it could enhance or destroy the U.S. position as the worlds primary space power. If the administration sticks with current plans to prepare the technology and make a final choice on the design for a new national space transportation system in 2006, the orderly process NASA and its contractors have been following will continue.
In all likelihood, this will lead to the a second generation RLV based on one of the Two Stage To Orbit designs now being worked on by Boeing, Lockheed Martin and the Orbital Sciences, Northrop Grumman team. These concepts do stretch the state of the art somewhat. They are very much on the bleeding edge, however, they are not revolutionary and will probably not lead to any major leaps forward in either space commerce or in the military uses of space. They will fulfill NASAs limited goals for the second Generation RLV: safety, reliability and a cost per pound to Low Earth Orbit (LEO) of less than $1,000 ( FY2000) dollars a pound.
While NASA says that the new system should be ready to begin operations in 2012, a date of 2015 is more likely. There is some evidence that the space agency is planning to be able to continue flying the Shuttle until 2020. This is a wise precaution, but the fact that they are making these plans shows a certain lack of confidence in the SLI process.
However, to fit the TSTO design into the outyear budget plans is not going to be easy. There is a well understood tendency to lowball cost estimates in order to make the numbers look good so that the Administration can claim that they are going to balance the budget, save Social Security, put two chickens in every pot and all the other things that political leaders promise to do. When it comes to large-scale, cutting edge technology projects this has, in the past, led to huge cost overruns and so on. The International Space Stations cost was always going to be much more than either the Clinton Administration or Congress let on. The sad thing was the way in which this useful fiction got in the way of sound management practices. Expensive projects that are obviously necessary are massaged through the political system, leaving the people who must run them with incompatible sets of requirements and budgets.
It will take considerable political courage to tell both OMB and the Congress that this is probably going to cost $20 billion over the next ten or fifteen years and will end with an adequate Shuttle replacement, but not one that will revolutionize the economics of the solar system. The 2nd generation design is going to be a good solid step on the way to revolutionary change but will be in and of itself a leap ahead disruptive technology. Given the need for crew safety and system reliability there is no reason to expect NASA to come up with something radical.
However, the TSTO system that would emerge from this process could become the basis for a much better vehicle. Just as the Shuttle has improved its performance and reliability since it first flew in 1981, a TSTO could be improved over time until it truly fitted the requirements of a commercially viable new set of space markets. A military version of the vehicle would evolve into something adaptable to the militarys various missions.
Today, both Boeing and Lock-heed Martin have designs that could become part of both a TSTO system and, before that, could be used as Liquid Fuel Flyback Boosters (LFFB) for the Shuttle replacing the Solid Rocket Boosters currently used to provide about 80% of the Shuttle systems total thrust. The use of such boosters would lead to a fairly smooth transition between the Shuttle as it exists today, and a future TSTO. If this were to be done, it is also likely that the costs of getting to orbit would only be marginally reduced.
Some astute observers feel that even a highly advanced TSTO system, if built under the current rules, regulations and philosophy, would neither be significantly more reliable nor cheaper. Airliner-like operations need airliner-like design principals and that will mean that the design teams will have to conduct a ruthless search and destroy mission against as many single point failure problems as possible. Improving safety and redundancy, as well as increasing the redundancy of the vehicles systems, structural weight will have to be added .
Naturally this will challenge the design teams to stay within the required Mass Fraction.
For an orbital vehicle, this means that the structure, engines, payload, etc., must weigh no more than 10% of total vehicle weight leaving 90% for fuel. Expendable rockets get around this problem by throwing away stages, essentially by feeding expensive bits of machinery to the fish. The essence of an RLV can be summed up in the phrase, everything goes up and everything comes back. This is what makes RLVs so hard to build.
The potential system requires that as many as three separate designs be built and tested before an item becomes operational.
This process leads to the delays and stretch outs that increase costs and frustrate the efforts of the industrys best and brightest. In other industries, such as computers, new products, ones that are just as complex as a rocket or RLV, are built and marketed in months rather than decades. The commercial aircraft industry is able to produce at least some new versions of the major Boeing and Airbus models every year. New versions of rockets seem to take at least eight or nine years to develop.
Since NASA cannot, for good reason, respond to normal marketplace incentives, a new type of carrot should be dangled in front of Americas space agency. The Moon and Mars are the institutions long term goals. If the President and Congress were to agree on a policy which said that when NASA truly reduced the cost of safely and reliably getting to orbit, from $10,000 dollars a pound to $600 or less, then they could begin work on going back to the Moon and building a permanent manned Moonbase. When they cut the cost to $100 or less, then they could begin work on a trip to Mars.
Until those goals are reached, NASA will have to content itself with the International Space Station and unmanned probes. The excitement and glory of sending the next batch of humans beyond low earth orbit should belong to NASA and to America. If China, or another power, were to build a Moonbase while the US was still arguing about TSTO architecture, the political shock would be huge. After Sputnik, President Eisenhowers approval number dropped 20 points. It is at least arguable that Nixon lost the 1960 election based on the Missile Gap issue, an issue which had both military and civilian components.
As it stands, there has been little hope that the government will, in the absence of some major crisis, commit the money and political capital needed for these ambitious projects. Fewer and fewer people have been willing to risk their careers on the chance that the U.S. will send people back to the Moon. A logical set of goals that would open space to affordable exploration and exploitation will attract the talent to make it happen. Men and women, who combined risk taking with a dedication to excellence, took America to the Moon in the sixties. If NASA is to survive as the worlds preeminent leader in human space travel, it must be given a doable mission and the resources to accomplish it.
A policy that would require NASA to reduce launch costs and then head out for the Moon and beyond, combines practicality and logic on the one hand, and idealism and ambition on the other. It would be saleable to Congress and the American people because it would not demand any funds from them until the costs had verifiably come down.
NASA needs an increase in its budget, but it should only get it after it has management and cost problems under control. Then, an increase on the order of one billion dollars would be in order for the FY 04 or 05 budgets. That increase should be, first of all, dedicated to upgrading the agencys infrastructure. Only then can NASA be considered ready for the challenge of a return to the Moon, and then, on to Mars.
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