Posted on by Fraser Cain

Silicate Found in a Meteorite

Image credit: WUSTL
Ann Nguyen chose a risky project for her graduate studies at Washington University in St. Louis. A university team had already sifted through 100,000 grains from a meteorite to look for a particular type of stardust ? without success.

In 2000, Nguyen decided to try again. About 59,000 grains later, her gutsy decision paid off. In the March 5 issue of Science, Nguyen and her advisor, Ernst K. Zinner, Ph.D., research professor of physics and of earth and planetary sciences, both in Arts & Sciences, describe nine specks of silicate stardust ? presolar silicate grains ? from one of the most primitive meteorites known.

“Finding presolar silicates in a meteorite tells us that the solar system formed from gas and dust, some of which never got very hot, rather than from a hot solar nebula,” Zinner says. “Analyzing such grains provides information about their stellar sources, nuclear processes in stars, and the physical and chemical compositions of stellar atmospheres.”

In 1987, Zinner and colleagues at Washington University and a group of scientists at the University of Chicago found the first stardust in a meteorite. Those presolar grains were specks of diamond and silicon carbide. Although other types have since been discovered in meteorites, none were made of silicate, a compound of silicon, oxygen and other elements such as magnesium and iron.

“This was quite a mystery because we know, from astronomical spectra, that silicate grains appear to be the most abundant type of oxygen-rich grain made in stars,” Nguyen says. “But until now, presolar silicate grains have been isolated only from samples of interplanetary dust particles from comets.”

Our solar system formed from a cloud of gas and dust that were spewed into space by exploding red giants and supernovae. Some of this dust formed asteroids, and meteorites are fragments knocked off asteroids. Most of the particles in meteorites resemble each other because dust from different stars became homogenized in the inferno that shaped the solar system. Pure samples of a few stars became trapped deep inside some meteorites, however. Those grains that are oxygen-rich can be recognized by their unusual ratios of oxygen isotopes.

Nguyen, a graduate student in earth and planetary sciences, analyzed about 59,000 grains from Acfer 094, a meteorite that was found in the Sahara in 1990. She separated the grains in water instead of with harsh chemicals, which can destroy silicates. She also used a new type of ion probe called the NanoSIMS (Secondary Ion Mass Spectrometer), which can resolve objects smaller than a micrometer (one millionth of a meter).

Zinner and Frank Stadermann, Ph.D., senior research scientist in the Laboratory for Space Sciences at the university, helped design and test the NanoSIMS, which is made by CAMECA in Paris. At a cost of $2 million, Washington University acquired the first instrument in the world in 2001.

Ion probes direct a beam of ions onto one spot on a sample. The beam dislodges some of the sample’s own atoms, some of which become ionized. This secondary beam of ions enters a mass spectrometer that is set to detect a particular isotope. Thus, ion probes can identify grains that have an unusually high or low proportion of that isotope.

Unlike other ion probes, however, the NanoSIMS can detect five different isotopes simultaneously. The beam can also travel automatically from spot to spot so that many hundreds or thousands of grains can be analyzed in one experimental setup. “The NanoSIMS was essential for this discovery,” Zinner says. “These presolar silicate grains are very small ? only a fraction of a micrometer. The instrument’s high spatial resolution and high sensitivity made these measurements possible.”

Using a primary beam of cesium ions, Nguyen painstakingly measured the amounts of three oxygen isotopes ? 16O, 17O and 18O ? in each of the many grains she studied. Nine grains, with diameters from 0.1 to 0.5 micrometers, had unusual oxygen isotope ratios and were highly enriched in silicon. These presolar silicate grains fell into four groups. Five grains were enriched in 17O and slightly depleted in 18O, suggesting that deep mixing in red giant or asymptotic giant branch stars was responsible for their oxygen isotopic compositions.

One grain was very depleted in 18O and therefore was likely produced in a low-mass star when surface material descended into areas hot enough to support nuclear reactions. Another was enriched in 16O, which is typical of grains from stars that contain fewer elements heavier than helium than does our sun. The final two grains were enriched in both 17O and 18O and so could have come from supernovae or stars that are more enriched in elements heavier than helium compared with our sun.

By obtaining energy dispersive x-ray spectra, Nguyen determined the likely chemical composition of six of the presolar grains. There appear to be two olivines and two pyroxenes, which contain mostly oxygen, magnesium, iron and silicon but in differing ratios. The fifth is an aluminum-rich silicate, and the sixth is enriched in oxygen and iron and could be glass with embedded metal and sulfides.

The preponderance of iron-rich grains is surprising, Nguyen says, because astronomical spectra have detected more magnesium-rich grains than iron-rich grains in the atmospheres around stars. “It could be that iron was incorporated into these grains when the solar system was being formed,” she explains.

This detailed information about stardust proves that space science can be done in the laboratory, Zinner says. “Analyzing these small specks can give us information, such as detailed isotopic ratios, that cannot be obtained by the traditional techniques of astronomy,” he adds.

Nguyen now plans to look at the ratios of silicon and magnesium isotopes in the nine grains. She also wants to analyze other types of meteorites. “Acfer 094 is one of the most primitive meteorites that has been found,” she says. “So we would expect it to have the greatest abundance of presolar grains. By looking at meteorites that have undergone more processing, we can learn more about the events that can destroy those grains.”

Original Source: WUSTL News Release

Posted on by Fraser Cain

Tom Hanks to Make New IMAX Film

Image credit: NASA
The IMAX Corporation today, in association with Academy Award-winning actor Tom Hanks, and aerospace technology leader Lockheed Martin Corporation, announced a new IMAX? 3-D space film, which will take moviegoers to the moon and allow them to walk side-by-side with the brave astronauts of the Apollo program.

IMAX will produce “Magnificent Desolation” along with Hanks’ and Gary Goetzman’s production company Playtone. Lockheed Martin will sponsor it.

“NASA is proud to collaborate with Playtone, as well as continue our successful relationships with IMAX and Lockheed Martin,” said Glenn Mahone, Assistant Administrator for Public Affairs at NASA Headquarters in Washington. “Tom Hanks’ enthusiasm for exploration is clearly evident in his previous productions that chronicle NASA’s remarkable history, and we believe ‘Magnificent Desolation’ is a wonderful opportunity to capture the interest and curiosity of the next generation of explorers.”

The film will take the audience to the surface of the moon, to the Ocean of Storms, the Fra Mauro Highlands and the Taurus Littrow Valley, as well as the Sea of Tranquility, as only IMAX? 3-D cameras can. “Magnificent Desolation” continues IMAX’s space film legacy and its unique production partnership with Lockheed Martin and NASA.

“We believe ‘Magnificent Desolation’ holds the potential to be extremely successful given the exciting subject matter and Tom Hanks’ passion and creative vision. The film will be designed by Playtone and IMAX to play at both commercial and institutional IMAX? theaters for many years,” said IMAX Co-CEOs and Co-Chairmen Richard L. Gelfond and Bradley J. Wechsler. “We are thrilled to partner once again with Lockheed Martin, which together with NASA and IMAX have created one of the highest-grossing large-format film franchises, featuring space films that have cumulatively grossed more than $350 million.”

“For nearly 20 years, Lockheed Martin has teamed with IMAX and NASA to produce films with the goal of educating and inspiring young and old about the wonders of math, science and technology through the prism of space,” said Dennis Boxx, Senior Vice President, Corporate Communications, Lockheed Martin Corporation. “And through our newly formed partnership with IMAX, NASA and now the creative team headed by Tom Hanks, a new generation will be enticed by the excitement and drama the astronauts of the Apollo program brought into our homes as they dared to dream of space and set foot on the lunar surface.”

IMAX? space films have been seen by over 85 million people and played in over 15 languages worldwide. The most recent collaboration between Lockheed Martin, NASA and IMAX was the extremely successful release of “SPACE STATION,” an IMAX? 3-D film released in April 2002, which has grossed nearly $70 million at the box office and continues to play in theaters worldwide.

For information about NASA and agency programs on the Internet, visit:

http://www.nasa.gov
For more information about the IMAX corporation on the Internet, visit:

http://www.imax.com

Original Source: NASA News Release

Posted on by Fraser Cain

Space Commercialization Bill Approved

Image credit: Scaled Composites
The House of Representatives today approved legislation, sponsored by Space and Aeronautics Subcommittee Chairman Dana Rohrabacher (R-CA), designed to promote the development of the emerging commercial human space flight industry. H.R. 3752, The Commercial Space Launch Amendments Act of 2004, would put in place a clear, balanced regulatory regime to promote the industry while ensuring public safety. The legislation now heads to the U.S. Senate.

“Through our hearings and other work on the bill, I have come to see this as one of the most important measures this Committee will move this year,” stated House Science Committee Chairman Sherwood Boehlert (R-NY). “This is about a lot more than ‘joy rides’ in space, although there’s nothing wrong with such an enterprise. This is about the future of the U.S. aerospace industry. As in most areas of American enterprise, the greatest innovations in aerospace are most likely to come from small entrepreneurs. This is true whether we’re talking about launching humans or cargo. And the goal of this bill is to promote robust experimentation, to make sure that entrepreneurs and inventors have the incentives and the capabilities they need to pursue their ideas. That’s important to our nation’s future.” Boehlert’s full statement follows this release.

Rohrabacher noted, “It is my sincere hope that this bill will encourage individuals like Burt Rutan and others to continue leading the way in pushing the boundaries of technology and safety by building and flight testing hardware, something NASA has yet to do. This fine piece of legislation carries forward my goal of promoting this new industry and cutting back bureaucratic red tape, while protecting the public health and safety.”

“No one can say for certain whether commercial human space flight will become a major industry. However, I believe that the provisions in H.R.3752 will help nurture its growth while at the same ensuring that public health and safety are protected,” said Science Committee Ranking Democrat Bart Gordon (D-TN).

Major provisions of the legislation are designed to:

* eliminate any confusion about who should regulate flights of suborbital rockets carrying human beings by explicitly locating all commercial space flight authority under the Federal Aviation Administration (FAA) Office of Commercial Space Transportation (AST);
* make it easier to launch new types of reusable suborbital rockets by allowing AST to issue experimental permits that can be granted more quickly and with fewer requirements than licenses;
* extend government indemnification for the entire commercial space transportation industry (including licensed, non-experimental commercial human space launches) for a period of three years, but the bill will not grant indemnification for flights conducted under experimental permits, which will be more lightly regulated; and
* require a study on how best to gradually eliminate indemnification for the commercial space transportation industry by 2008 or as soon as possible thereafter.

Today’s House passage represents the culmination of a long and thorough process beginning last July with a joint House-Senate hearing, a Space Subcommittee hearing last fall and a policy roundtable with experts in the commercial space transportation industry late last year.

“Today, the U.S. House of Representatives has led the nation toward a significant next step in developing space and creating a major new economic engine for powering our nation’s economy. With the passage of HR 3752, the House has demonstrated real vision for America’s future in space. This bill helps define the critical framework for a commercial space regulatory process and authorizes the very important federal agency that is responsible for commercial space regulation. The leadership of both the House Subcommittee on Space and the House Committee on Science should be highly commended for their work in passing this bill,” said Tim Huddleston, Executive Director of the Aerospace States Association.

“H.R. 3752 is precisely the kind of legislation Congress should enact in order to give investors like me confidence that our space tourism ventures will be regulated in a fair and streamlined manner. I hope the Senate takes up this bill soon and sends it on to President Bush for his signature.,” stated Dennis Tito, the first space tourist in history.

Jeff Greason, President of Xcor Aerospace, a private rocket firm with goals of sending human beings into space said, “We think H.R. 3752 is very carefully crafted legislation which will help commercial human spaceflight develop in America. Confirming the FAA’s definition of suborbital flight, establishing a ‘fly at your own risk’ human spaceflight regime, and creating the new ‘experimental permit’ framework are all important steps which we fully support. We hope the bill moves through Congress swiftly retaining these key provisions.”

Original Source: House Committee on Science

Posted on by Fraser Cain

NASA Finds Smoke Can Choke Clouds

Image credit: NASA
Using data from NASA’s Aqua satellite, agency scientists found heavy smoke from burning vegetation inhibits cloud formation. The research suggests the cooling of global climate by pollutant particles, called “aerosols,” may be smaller than previously estimated.

During the August-October 2002 burning season in South America’s Amazon River basin, scientists observed cloud cover decreased from about 40 percent in clean-air conditions to zero in smoky air.

Until recently, scientists thought aerosols such as smoke particles mainly served to cool the planet by shading the surface, either directly, by reflecting sunlight back toward space, or indirectly, by making clouds more reflective. Certain aerosols make clouds’ droplets smaller and more numerous, thereby making the clouds more reflective while reducing the amount of sunlight reaching the surface.

However, this new study proves smoke aerosols have a “semi- direct” effect on climate, causing a reduction in cloud cover and warming the surface. In the morning, smoke absorbs incoming solar radiation and heats the atmosphere while cooling the surface. Since there is less upward transport of warmth and moisture in such conditions, clouds are less likely to form. Then, in the afternoon, since there is less cloud cover, more sunlight passes through the atmosphere and warms the surface.

“This instantaneous warming is important and can dramatically affect the people and the Amazonian ecosystem,” said Ilan Koren, research scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md.

Koren is lead author of a paper in the current issue of Science. Using Aqua data, Koren and his NASA co-authors measured the total amount of light reflected through the top of the atmosphere. From those data they determined how much area was covered by clouds and how much by smoke. They also estimated the smoke’s “optical thickness,” a measure of how much sunlight the smoke prevented from traveling down through a column of atmosphere.

The team found the smoke and clouds together would ordinarily reflect solar energy equal to one 28-watt light bulb per square meter back up into space (i.e., a cooling effect). With the reduction in cloud cover, however, solar energy equal to one eight-watt light bulb per square meter is absorbed within Earth’s climate system (i.e., a warming effect).

The team consulted other weather data to make sure the differences in cloud patterns were not due to regional differences in meteorology. Once team members proved the meteorological conditions were the same in the smoky regions as they were in the cloudy regions, they knew the smoke had to be the reason average cloud cover dropped from 40 percent to zero in the presence of heavy smoke.

“We used to think of smoke mainly as a reflector, reflecting sunlight back to space, but here we show that, due to absorption, it chokes off cloud formation,” Koren said.

According to Koren, smoke inhibition of cloud formation is not unique to the Amazon area. His team has seen similar examples in other parts of the world, including over parts of Africa during the burning season, and over Canada during major boreal forest wildfires. When added up over the entire globe, the warming influence of smoke and other absorbing aerosols suggests the global cooling influence of these particles is much smaller than current models predict.

Smoke and aerosol inhibition of cloud formation was first proposed in two previous NASA studies based upon results of computer model experiments. However, this study documents the first time this effect of smoke on clouds has been measured in Earth’s environment. The research was funded by NASA’s Earth Science Enterprise. The Enterprise is dedicated to understanding the Earth as an integrated system and applying Earth system science to improve predication of climate, weather and natural hazards using the unique vantage point of space.

Original Source: NASA News Release

Posted on by Fraser Cain

Peering into the First Moments After the Big Bang

Image credit: RAS
Using a British radio telescope called the Very Small Array (VSA), located on the flanks of Mount Teide in Tenerife, astronomers from the Universities of Manchester and Cambridge and the Instituto de Astrofisica de Canarias (IAC) have made measurements of the Cosmic Microwave Background (CMB) – radiation left over from the Big Bang – which shed new light on events in the first minute fraction of the Universe’s existence.

By combining their results with those of NASA’s Wilkinson Microwave Anisotropy Probe (WMAP) satellite, they have been able to constrain the behaviour of the Universe during the ‘inflationary’ phase believed to have taken place when it was only 10(-35) seconds old. If confirmed, these results will significantly challenge our current views of inflation and the first moments of creation.

Dr. Richard Davis of Jodrell Bank Observatory, University of Manchester, who was involved in the design and building of the VSA and leads the Jodrell Bank team, said, “From the holiday island of Tenerife we have probed the first moment of creation, when the Universe was a million-million-millionth of the size of the atom. Using this British-funded instrument, we see echoes of the crazy expansion which took place in the early Universe; it is quite incredible!”

The idea of inflation is that the Universe expanded extremely quickly during its very early existence, creating a Universe whose properties are very uniform on the largest scales. However Quantum Mechanics, the theory of the sub-atomic world, would have created minute fluctuations in the density of the early Universe which eventually led to the formation of galaxies such as our own Milky Way. These fluctuations also imprinted minute temperature variations on the observed CMB, so allowing them to be studied by extremely sensitive instruments such as the VSA.

The Quantum Mechanical fluctuations produced variations in density and temperature over a very wide range of scale sizes. The finer detail of the VSA observations, as compared with those of WMAP, has enabled a better understanding of how the distribution of these fluctuations varies as a function of size.

Previous ideas had suggested that, once the subsequent history of the Universe is accounted for, the distribution of fluctuations would be independent of scale. However, the current results show that the fluctuations are most apparent at an angular scale of about 1/2 degree, the size of the Moon in the night sky. On both larger (the size of the Universe) and smaller (the size of a cluster of galaxies) scales, these variations in density and temperature are much less.

“The most popular inflation models predict much smaller variations than those seen in the new observations,” said Dr. Richard Battye (Jodrell Bank Observatory), who was involved in the analysis and interpretation of the data. “The increasing sensitivity of instruments such as the VSA is enabling us to test these inflation models. The results are not totally conclusive at this stage, but if true they will require a complete re-think of the prevailing view of the first moments of creation.”

The results from the VSA have been confirmed by a concurrent experiment, the Cosmic Background Imager (CBI), which is located high in the Chilean Andes and operated by the California Institute of Technology. The results at this stage are highly suggestive, but it is hoped that further measurements by the VSA, CBI and eventually the PLANCK satellite, will allow more definitive conclusions to be drawn. PLANCK, which is due to be launched by the European Space Agency in 2007, will employ highly sensitive receivers built by engineers at the Jodrell Bank Observatory.

Two papers detailing these results have been submitted to the Monthly Notices of the Royal Astronomical Society.

Original Source: RAS News Release

Posted on by Fraser Cain

Asteroid Bill Passes

Image credit: NASA
H.R. 912, the Charles “Pete” Conrad Astronomy Awards Act, named for the third man to walk on the moon, establishes awards to encourage amateur astronomers to discover and track near-earth asteroids. The bill directs the NASA Administrator to make awards, of $3,000 each, based on the recommendations of the Smithsonian Minor Planet Center. Earth has experienced several near misses with asteroids that would have proven catastrophic, and the scientific community relies heavily on amateur astronomers to discover and track these objects.

“Given the vast number of asteroids and comets that inhabit Earth’s neighborhood, greater efforts for tracking and monitoring these objects are critical. That is why I introduced H.R. 912, the Charles ‘Pete’ Conrad Astronomy Awards Act, which is a tribute to Pete Conrad for his tremendous contributions to the aerospace community over the last four decades,” said bill sponsor, Space and Aeronautics Subcommittee Chairman Dana Rohrabacher (R-CA). “Asteroids deserve a lot more attention from the scientific community. The first step is a thorough tracking of all sizeable Near Earth Objects, and H.R. 912 is a modest step towards this goal.”

Original Source: House Committee On Science News Release

Posted on by Fraser Cain

Landsat 5 Reaches 20 Years in Space

Image credit: NASA
March 1, 2004, marks the 20th anniversary of operations of the NASA/USGS ‘workhorse’ satellite, Landsat 5. Landsat 5, launched on March 1, 1984, continues to provide important observations of the landmass of the planet and has established a record for reliability in the civilian space fleet.

When Landsat 5 was launched from Vandenberg Air Base in California, expectations were for two years of effective operations, with a goal of three years of data collections. Instead, after 100,000 orbits and the acquisition of over 29 million images, Landsat 5 continues to operate successfully.

“The longevity and importance of the Landsat 5 mission is nothing short of incredible,” said Darrel Williams, Landsat 7 Project Scientist at NASA’s Goddard Space Flight Center. ” The imagery provided over it’s 20 year history has helped us to develop a far better understanding of the land surface features on our home planet, as well as how man has acted to modify those features. It has resulted in the creation of an unsurpassed “digital photo album” of Earth that will be repeatedly opened and reviewed by generations to come.”

Landsat 7 joined Landsat 5 in global observations in 1999. For four years the two earth observing satellites provided extensive, frequent coverage. “In May of 2003, Landsat 7 developed problems with the scan line corrector on the ETM+ sensor, stated Landsat Program manager Tracy Zeiler. “Since then, in addition to degraded Landsat 7 data, scientists have returned to relying on Landsat 5 observations. Landsat 5 has proven, again, to be a remarkably reliable source of information.”

The “workhorse” satellite continues to perform. While Landsat 5 continues to operate, Landsat Program managers are working on a replacement vehicle. The expected end-of -life, based on fuel reserves, is projected for early 2009. Until then, the NASA/USGS Landsat 5 will continue to provide records of a changing world.

For Additional Information on the Landsat Program, visit: http://landsat.gsfc.nasa.gov/

Original Source: NASA News Release

Posted on by Fraser Cain

Wallpaper: Hubble’s New Image of V838 Monocerotis

Image credit: Hubble
“Starry Night,” Vincent van Gogh’s famous painting, is renowned for its bold whorls of light sweeping across a raging night sky. Although this image of the heavens came only from the artist’s restless imagination, a new picture from NASA’s Hubble Space Telescope bears remarkable similarities to the van Gogh work, complete with never-before-seen spirals of dust swirling across trillions of miles of interstellar space.

This Hubble wallpaper, obtained with the Advanced Camera for Surveys on February 8, 2004, is Hubble’s latest view of an expanding halo of light around a distant star, named V838 Monocerotis (V838 Mon). The illumination of interstellar dust comes from the red supergiant star at the middle of the image, which gave off a flashbulb-like pulse of light two years ago. V838 Mon is located about 20,000 light-years away from Earth in the direction of the constellation Monoceros, placing the star at the outer edge of our Milky Way galaxy.

Called a light echo, the expanding illumination of a dusty cloud around the star has been revealing remarkable structures ever since the star suddenly brightened for several weeks in early 2002. Though Hubble has followed the light echo in several snapshots, this new image shows swirls or eddies in the dusty cloud for the first time. These eddies are probably caused by turbulence in the dust and gas around the star as they slowly expand away. The dust and gas were likely ejected from the star in a previous explosion, similar to the 2002 event, which occurred some tens of thousands of years ago. The surrounding dust remained invisible and unsuspected until suddenly illuminated by the brilliant explosion of the central star two years ago.

The Hubble telescope has imaged V838 Mon and its light echo several times since the star’s outburst in January 2002, in order to follow the constantly changing appearance of the dust as the pulse of illumination continues to expand away from the star at the speed of light. During the outburst event, the normally faint star suddenly brightened, becoming 600,000 times more luminous than our Sun. It was thus one of the brightest stars in the entire Milky Way, until it faded away again in April 2002. The star has some similarities to a class of objects called “novae,” which suddenly increase in brightness due to thermonuclear explosions at their surfaces; however, the detailed behavior of V838 Mon, in particular its extremely red color, has been completely different from any previously known nova.

Nature’s own piece of performance art, this structure will continue to change its appearance in coming years as the light from the stellar outburst continues to propagate outward and bounce off more distant black clouds of dust. Astronomers expect the echoes to remain visible for at least the rest of the current decade.

Original Source: Hubble News Release

Posted on by Mark Mortimer

Book Review: Sojourner, An Insider’s View of the Mars Pathfinder Mission

Sojourner was one of the first of NASA’s and JPL’s mandated faster, better, and cheaper projects. Before this mandate, a mission’s reliability was paramount and costs were correspondingly high. Sojourner’s predecessor, the Cassini mission, costed close to $1 billion. On the other hand, the Mars Pathfinder (Sojourner and the lander) mission had a total budget of $171 million. The Sojourner rover itself was capped at $25 million for design, parts, development, assembly, tests, and all operations during the mission. In spite of this, or perhaps because of this, there is a lot of evidence of solid managerial support, coupled with the workers’ nearly desperate attempts to scrounge resources and time. The book is a compendium of the problem definitions, the trial solutions, and the convergence to a workable solution that Mr. Mishkin and his colleagues faced for more than 10 years. Nevertheless, the skill, belief, and perseverance of many people made Sojourner faster, better, cheaper, and most importantly successful.

Sojourner’s design roots extended to the Lunar Surveyor Vehicle prototype that was planned for the moon but never used. This robot, nearly trashed, was resurrected by a JPL tinkerer with an interest in locomotion, vehicle suspension, and autonomous direction finding. From this beginning, serendipity plays its part as fortuitous events led to this rover, or one of its offspring, being demonstrated at the right time and before the right people to ensure that funding continued. Earth itself is a daunting realm for autonomous rovers, but Mars was a totally new territory. The temperature range was large, 110F over the duration of a day. The terrain was rough and unpredictable, sand could capture a wheel, or a ledge may roll the rover. Most of all, the 20 minute communications made direct control impossible. The first part of the book largely deals with tackling and overcoming this. It describes getting a solution to accommodate an acceptable body size, an optimal number of wheels, a forgiving suspension, and a safe guidance system. The later part of the book largely deals with the challenges of integrating the many prototypes, their unit testing, and the ensuing system testing.

In addition to designing a robotic rover, the book provides a glimpse of the challenges that face anyone taking on the role of a systems engineer. This role is to balance the needs, requirements, and expectations of all the players of a project so that there is a working solution. The solution is not necessarily optimal for anyone as everyone’s needs often directly conflict with others. The result is that no one is totally satisfied or completely happy. Mr. Mishkin displays a lot of the personality of his colleagues and himself as trade-offs are made, deals are done, and the rover comes together. This lends a wonderful human touch to what otherwise might be a somewhat dry and technical book. In accomplishing his goal Mr. Mishkin received some of the best words of praise for a systems engineer which are, “When you work on a job, things happen. Things get done”.

Though this book is enjoyable to read, it is difficult to classify. There is a lot of discussion on the technical aspects of resolving issues that arose in designing Sojourner, but there is too little to recommend it as a design reference. The challenges of being a systems engineer in a large project comes out loud and clear, but there is little to offer a new systems engineer on lessons learned. There is a lot of detail on the bugs, errors, and complications that needed correcting, but it is not really a comprehensive story of Sojourner. Further, there is no presentation of the scientific results. In the end, this book is exactly what it was meant to be, the personal memoirs of a technical expert from an exciting and challenging project.

I enjoyed seeing the historical thread that the Sojourner project wove amongst people and events. I particularly liked how it connected the lunar rover project of the 1950’s up to the start of the Spirit and Opportunity projects. As well, I could easily grasp the intangible value of team spirit, mutual support, and a work ethic that goes beyond a pay cheque. This is a book for engineers, especially those with an interest in robotics or space exploration. A person contemplating being a systems engineer would also enjoy reading this book to see the amazingly good things to which serendipity can lead.

Review by Mark Mortimer

Read more about the book at Amazon.com

Posted on by Fraser Cain

The Moon and Jupiter – Side By Side

Image credit: NASA
Lately Earth and Jupiter have been approaching one another, and this week the two worlds are only 400 million miles apart. That’s what astronomers call “a close encounter.”

400 million miles is close–on the vast scale of the solar system. Consider Pluto. It’s nearly ten times farther away than Jupiter. Or Saturn. The ringed planet is 800 million miles away. Nevertheless, Saturn looks wonderful right now, and Jupiter is even better.

400 million miles makes Jupiter ten times brighter than Saturn, and twenty-five times brighter than a 1st magnitude star. It outshines everything else in the sky except Venus, the Moon and the Sun.

See for yourself.

Step outside after sunset any night this week and look east. Jupiter is that very bright “star” near the horizon–not to be confused with even brighter Venus in the west. By 9 p.m. Jupiter will be high in the eastern sky, simply dazzling.

On March 4th, the date of closest approach, and March 5th, Jupiter will appear right beside the full Moon in the constellation Leo. So you won’t need a sky map to find Jupiter, just look for the Moon.

If you have a telescope, point it at Jupiter. Even a small ‘scope will reveal Jupiter’s rust-colored cloud belts and its four largest moons. Io, Europa, Callisto and Ganymede look like a dim line of stars straddling the giant planet. Sometimes only two or three moons are visible. That’s because one or two of them are behind Jupiter. Look again later or perhaps tomorrow. The missing moons will come out of hiding as they circle their planet.

The four “Galilean satellites”–so named because they were first observed by Galileo Galilei in 1610–are among the weirdest worlds in the solar system. Io looks like a pizza, and it has active volcanoes that spew sulfurous snow. Europa and Callisto are icy places, hiding, perhaps, the biggest oceans in the solar system beneath their frozen crusts. Ganymede is simply big–larger than Pluto and Mercury, and almost as wide as Mars. If it orbited the sun instead of Jupiter, Ganymede would be considered a full-fledged planet.

Sometimes you can see dark spots creeping across Jupiter. These are shadows cast by the four big moons. Sky & Telescope magazine publishes a schedule of shadow crossings, so you can find out when to look. The crossings are fun to watch through a telescope.

Another thing to look for is Jupiter’s Great Red Spot–a cyclone twice the size of Earth, and at least 100 years old. It swirls across Jupiter’s middle approximately every 10 hours. Again, check Sky & Telescope for viewing times.

First-time observers of Jupiter, squinting through the eyepiece of a small telescope, don’t always believe what they see. The giant planet looks slightly squashed. Is there something wrong with the optics? No, Jupiter really is flattened. The giant planet, 11 times wider than Earth, spins on its axis in only 9 hours and 55 minutes. Speedy rotation gives Jupiter an equatorial bulge. The “squash” is real.

So is the pizza moon, the giant cyclone, the alien oceans. They’re all just 400 million miles away. This is a close encounter you won’t want to miss.

Original Source: NASA Science Story