It was an exciting year in 2006 and 2007 for science on the International Space Station. New research facilities were installed and new investigations had begun, while the results of a wide variety of investigations began to be published in scientific literature. Here are just a few highlights of the past year, and some great investigations to watch for in the remainder of 2007.

MISSE

Results from previous investigations in the Materials on the International Space Station Experiment (MISSE), suite have enabled a major step forward in understanding atomic oxygen undercutting underneath protective coatings, as well as in the development of a comprehensive set of models and observations for existing and new spacecraft materials. These experiments also have successfully proved several types of more efficient advanced solar cells with an understanding of their efficiency and performance in the space environment.

Image at right: This image of the MISSE-3 Passive Experiment Container (PEC) was taken on December 18, 2006. At this point, MISSE-3 has been exposed to the space environment for approximately 4 months. Credit: NASA

MISSE 3 and 4, which are the latest in a series of suitcase-sized testbeds attached to the outside of the space station, were successfully deployed during extravehicular activity, or EVA 5, on August 3, 2006. Approximately 875 specimens of various materials contained in suitcase-like cases called passive experiment containers were mounted directly to the outside of the station and will remain there for approximately one year until the 13A.1 (STS-118) flight. The samples are for 40 different investigators including NASA centers, military space organizations and aerospace contractors and manufacturers. These specimens will be exposed to the harsh environment of microgravity to observe the effects that atomic oxygen, ultraviolet light and thermal conditions have on materials.

The specimens include a variety of materials such as paint and protective coatings that will be used on future spacecraft such as satellites. Environmental monitors will record the thermal cycling, or change in temperature, that is occurring. New material that might be used in the next generation of EVA suits is being tested to examine how that material reacts to the harsh environment.

Three million basil seeds have been placed in containers that are located underneath the trays on MISSE 3 and 4. Once the seeds have been returned to Earth, they will be distributed to school children for them to plant and observe the differences between seeds exposed to space and seeds that have remained on Earth.

MELFI and Nutrition Status Assessment

Getting the Minus Eighty Degrees Celsius Laboratory Freezer for ISS (MELFI) operating on orbit and starting comprehensive medical studies that rely on it was another significant accomplishment of 2006. MELFI provides the space station with refrigerated volume for storage and fast-freezing of life science and biological samples. It also ensures transportation of conditioned specimens to and from the station by flying in fully powered mode inside the Multi-Purpose Logistics Module, or MPLM. Before MELFI, it was not possible to assess nutritional status during flight because blood and urine could not be collected, stowed frozen and returned during space station missions.

Image at right: Expedition 14 Commander and NASA Astronaut Michael Lopez-Alegria inserts blood and urine samples into the Minus Eighty Degree Laboratory Freezer for ISS (MELFI) until they can be returned to Earth for analysis. Credit: NASA

One of the first investigations to take advantage of sample storage in MELFI is Nutrition Status Assessment (Nutrition). This experiment is about a lot more than nutrition -- it goes to the heart of human physiology in space. Data from typical medical monitoring on the station indicated significant declines in vitamin D status related to bone loss, folate, and vitamin B-6; significant loss of body mass; and unhealthy increases in serum iron. As a medical experiment, Nutrition will give us the first profiles of changes in important physiological indicators during the course of a long-duration mission. Beginning with the Expedition 14 crew, blood and urine samples are being collected near Flight Days 15, 30, 60, 120, and 180 and then stored in the MELFI freezer for future return.

The experiment significantly expands the number of biomarkers to be measured in the blood and urine. Additional markers of bone metabolism will be measured to better monitor bone health and countermeasure efficacy. New markers of oxidative damage will be measured to better assess the type of radiation and other oxidative impacts during space flight. The array of nutritional assessment parameters will be expanded to better understand changes in folate, vitamin B-6 status and related cardiovascular risk factors during and after flight. Additionally, stress hormones and hormones that affect bone and muscle metabolism will be measured. This investigation represents the most comprehensive monitoring of a broad array of physiological indicators that NASA has ever completed for long-duration space flight.

SPHERES

In 2006 and 2007, the crew performed one-, two-, and three-unit tests of formation flying for Synchronized Position Hold, Engage, Reorient, Experimental Satellites (SPHERES). These are iterative tests with dynamic computer learning inside the station cabin in which bowling ball-sized spheres perform various maneuvers with the spheres operating simultaneously. The investigators have moved through several substantial changes in software, and the spheres have learned how to negotiate the cabin environment and maintain positions relative to one another.

Image at right: Three satellites fly in formation as part of the Synchronized Position Hold, Engage, Reorient, Experimental Satellites (SPHERES) investigation. This image was taken during Expedition 14 in the Destiny laboratory module. Credit: NASA

Information learned from this experiment may lead to simpler autonomous docking allowing for servicing, re-supplying, reconfiguring and upgrading of space systems. SPHERES results also support the development of autonomous spacecraft to carry out a variety of tasks in a space environment. Smaller autonomous spacecraft could, with the right coordination and programming, perform tasks too complicated or too expensive for larger spacecraft to execute.

New Opportunities for Students to Participate in Space Experiments

The University of Colorado in Boulder and BioServe Space Technologies have launched the first of a planned series of investigations that will allow students to participate in space research. The Commercial Generic Bioprocessing Apparatus Science Insert – 01 (CSI-01) was delivered to the station on the 12A.1 (STS-116) flight in December 2006. It included two different types of habitat inserts—for seed germination and for culturing roundworms called Caenorhabditis elegans, or C. elegans.

Image at right: This image shows several Caenorhabditis elegans, small nematode worms, on-orbit during Expedition 14 on January 24, 2007. Credit: NASA

The worm experiment began on January 10, 2007 on the station. It builds on previous biological studies of worms in space as model organisms for studying risks associated with radiation, microgravity and other variables experienced in the space environment. Partnered with the Orion’s Quest curriculum, the C. elegans experiment involves over 5,000 middle school students in the United States and several thousand students in Malaysia. The C. elegans were returned to Earth during the 13A (STS-117) mission in June 2007.

The seed germination experiment began February 16, 2007, with more than 2,000 third graders participating in this pilot program. The curriculum for the student investigations is being implemented in partnership with Agronauts at North Carolina State University in Raleigh. The students grow radish and alfalfa seeds in their classrooms at the same time as the seeds germinate and grow on orbit. Students then examine root and stem growth of the two plants and compare seeds germinated on Earth to those germinated on the space station. The results of these experiments will help students understand the concept of gravitropism as well as issues scientists face when planning to grow plants in space.

Top Science Activities to Watch for in 2007:

Integrated Immune

A new study of the immune system in orbit will start with the 10A (STS120) flight. We know that crew members show all kinds of signs of degradation in immune function during long-duration flight; a few times it has already put missions at risk of early termination. There are several possible causes ranging from microgravity to stress to radiation. To devise a countermeasure to prevent immune dysfunction, a valid monitoring technique must be developed. The Integrated Immune study will obtain comprehensive measurements of the different immune pathways during the mission so that we will know which compartments of the immune system are really affected, allowing the development of targeted countermeasures. Since there are no procedures currently in place to monitor immune function or its influence on crew health, we are looking forward to the results of this experiment.

SAME

The Smoke and Aerosol Measurement Experiment (SAME) will be delivered to the station on the 10A (STS-120) flight. This experiment burns sample space materials, measures the soot and smoke particles and compares the two different technologies used in shuttle and the station smoke detectors to identify their performance in detecting smoke from a variety of sources. Since shuttle experimental data shows that smoke, like flames, is much different in microgravity, this experiment will determine the best smoke-detection technology. Results from this experiment will help identify ways to improve smoke detectors on future spacecraft. Crew Exploration Vehicle teams are also waiting for the data to finalize their smoke detection requirements. In addition to analyzing smoke detection, SAME will impact fire-suppression approaches.

EPO-Kit C

The Education Payload Operations - Kit C Plant Growth Chambers (EPO-Kit C) is part of the 13A.1 (STS-118) mission. This experiment is an on-orbit plant growth investigation using basil seeds. The still and video imagery acquired will be used as part of a national engineering design challenge for students in grades K-12. Students will grow basil seeds -- control and flown seeds -- to conduct their own science experiments on plant growth using growth chambers created by the students on the ground.

Image at right: Basil plants grown from seeds, on Earth, in a simple plant growth chamber (opened). Credit: NASA

On orbit, crew members will capture video of the transfer of two, small collapsible growth chambers for EPO-Kit C. The video will include a discussion of the growth chambers by the crew members and will be used during Phase I and Phase II of the national engineering design challenge. The video will be distributed to education organizations to be incorporated into education products for students in grades K-12. Crew members also will conduct a 12-day to 21-day on-orbit plant growth investigation using basil seeds. The plant growth inside the growth chambers will be documented with still digital imagery.

Multigen

Molecular and Plant Physiological Analyses of the Microgravity Effects on Multigeneration Studies of Arabidopsis thaliana (Multigen) is a cooperative investigation with the European Space Agency (ESA). This experiment will examine the growth of Arabidopsis thaliana (thale cress) over three generations to determine the effects of microgravity on the plant. Multigen will utilize the European Modular Cultivation System (EMCS) facility on board the International Space Station. EMCS is an experiment facility for biological investigations in microgravity.

The investigation will have three phases. In the first phase (Multigen-1), the seeds will grow and develop into mature seed-bearing plants after watering on the station. These plants will be dehydrated to harvest the seeds. The seeds will be stowed and returned to Earth for morphological testing. A portion of the seeds will be returned to the station for the second generation of thale cress plants for Multigen-2. Once the second generation of plants reaches maturity and bears seeds, the plants will be dehydrated once again and the seeds will be harvested. These seeds will be stowed on the station and returned to Earth for morphological studies. A portion of these seeds will be returned to the station for Multigen-3. Once the third generation of plants reaches maturity, the plants will be dehydrated and stowed for return to Earth for further testing.

07.19.07

A NASA researcher has developed a new method to anticipate food shortages brought on by drought. Molly Brown of NASA’s Goddard Space Flight Center in Greenbelt, Md., and her colleagues created a model using data from satellite remote sensing of crop growth and food prices.

Brown conceived the idea while working with organizations in Niger, West Africa, that provide information regarding failed crops and help address local farmers' worries about feeding their families. Brown's new approach could improve the ability for government and humanitarian aid officials to plan and respond to drought-induced food price increases in Niger and elsewhere.

Supply and demand largely dictate food prices, with greater supply leading to lower prices and less supply leading to higher prices. During a food crisis in semi-arid regions like Niger, food shortages are often brought on when lack of rainfall significantly reduces the amount of grain farmers are able to grow. Farmers in regions like Niger are able only to grow a few drought-resistant crops, and therefore must buy grain at unaffordably high prices at the end of the year to make up for shortfalls in production. This scenario could drive a drought-driven food security crisis. A lack of locally-produced and affordable grain, coupled with increased prices and reduced access to food, could lead to starvation and hunger-related illness in the most vulnerable segments of society.

Images right: The left image shows how dry season climate browns millet crops in a farmer's field when compared to the right image taken during the Wet season when millet crops grow green and lush in the same farmer's field. The images illustrate the stark differences between crops that receive adequate rainfall and those that do not, whether in countries like Senegal (where photos were taken) or in countries like Niger. Credit: Molly Brown/NASA

Brown, the lead author of a study to be published early next year in the journal Land Economics, said that until now officials have primarily studied the after effects of occurrences like floods or droughts that might affect crop production as their best means of warning of a coming food security crisis. "With this new study, for the first time we can leverage satellite observations of crop production to create a more accurate price model that will help humanitarian aid organizations and other decision makers predict how much food will be available and what its cost will be as a result. This is a unique opportunity for an economic model to take climate variables into account in a way that can aid populations large and small," she said.

Agricultural economists often use a mathematical formula and typically data on crop yield, a range of market prices, and other variables to develop a price model that estimates what food prices may be in the marketplace. Brown applied remote-sensing data in an economic model producing an enhanced way for aid officials to combat a problem that affects 3.6 million people in Niger alone.

To use their price model in a real-world situation, Brown and her colleagues compared variations in crop production to variations in food prices in parts of West Africa. They focused on a sample crop, a drought-resistant grain called millet. Locally, people use millet to create a couscous-like dish. Brown's team observed the June-September wet season to the October-May dry season – and the amount and growth rate of green vegetation. Then, it studied how seasonal climate differences affected the crop’s price in local markets.

Image left: Farmers sell their millet crops at outdoor markets like this one in Senegal. Credit: Molly Brown/NASA

Brown used long-term data from sensors on NASA-built satellites to gauge the density of local plant life, an indicator of the strength of the crop. From space, sensors pick up reflections from the ground to determine the ground’s “greenness” and enable researchers to estimate the amount of rainfall. Those data in turn may be used to estimate the amount of grain that crops will produce. Brown combined the satellite data and climate variables with the price model to create maps of millet prices covering a complete area. With these maps decision makers can predict price changes, food availability and ultimately food insecurity.

Food prices are not determined solely by human action. Climate variables affect about 20 percent of the process of market pricing, according to the study's co-author Jorge Pinzon, a research scientist and mathematician at Goddard. This is a factor that decision makers often do not take into account when analyzing food security, Pinzon said.

"It is critical to include climate and environmental variables in food security planning when piecing together all of the forces that come together to create famine," said Pinzon. "This model can help officials better understand the role that climate plays in food availability and pricing, and also in famine warning when applied to a real-time planning effort."

Brown believes that information provided by this new technique can aid organizations that are part of the U.S. Agency for International Development's (USAID) Famine Early Warning System to stem suffering that occurs every year from food crises. Brown hopes that her method, funded by NASA and USAID, may eventually help the farmers in Niger more effectively plan what to grow and when to grow it to earn a living wage.

"This price model can be used in any region of the world where there are seasonal climate factors that can contribute to local food production crises," said Brown. "Even a country with normally adequate food production can still experience a food crisis if a drought hits. We hope that decision makers will work together with scientists to apply this model so that even a farmer on a small plot of land can better sustain his family during a drought."

ESA’s Venus Express and NASA’s MESSENGER booked an appointment at Venus late in the evening of 5 June, to look at the oddities of this mysterious planet in tandem for a few hours. Just a few weeks on, scientists from both teams are ready to present a first set of images.

Image right: As NASA’s MESSENGER departed from Venus on 5 June 2007 to continue its journey towards Mercury, its Wide Angle Camera captured a sequence of 50 images (480-nm wavelength filter) showing the planet disappearing in the distance. Initially, images were acquired at a rate of one of every 20 minutes and then, with increasing distance, the timing interval was increased to 60 minutes. Click image to view movie. Credit: NASA/APL

This unique opportunity to make multi-point observations of the Venusian atmosphere was possible thanks to the MESSENGER (MErcury Surface, Space ENvironment, Geochemistry, and Ranging) swingby of Venus – a key step during its long journey to Mercury - while Venus Express was already orbiting the planet in the course of its mission.

The two spacecraft carry sets of instruments employing different observation techniques which complement each other. The data collected at Venus are now being analysed by teams on both sides of the Atlantic and, as can be appreciated in the first images presented here, already hints at the potential of the results to come.

The particular orbital geometry of Venus Express when MESSENGER skimmed past Venus on 5 June meant that the two spacecraft were not at the same location (with respect to the surface of the planet) at the exact same time.

VIRTIS Image of the Area Overflown by MESSENGER

Image left: This grey-scale image, obtained by the VIRTIS instrument on board ESA’s Venus Express, shows the atmospheric region of Venus over which NASA’s MESSENGER passed on 5 June 2007. The region of MESSENGER’s closest approach is in the night side (marked by a circle). Credits: ESA/VIRTIS/INAF-IASF/Obs. de Paris-LESIA

MESSENGER made its closest approach at a distance of about 338 km from the planet over the planetary coordinates 12.25° South and 165° East, on the night side of the planet. Meanwhile, Venus Express was behind the horizon, almost right above the South Pole, at about 35 000 km from Venus.

So how could they make true joint observations of the same regions and phenomena? Scientists came up with a highly creative solution.

Two Hunters for the Same Cloud

The scientists used a computer simulation based on real atmospheric data about Venus obtained from previous ground and space observations. Knowing the speed of the local winds, which depend both on the altitude and the latitude, they were able to predict where a particular set of clouds would be at a given point in time.

For their observation, the Venus Express scientists selected a cloud that – moving west by about 90° longitude every day - was visible to Venus Express and would be in view of MESSENGER 12 hours later, at the time of its closest approach. The same cloud became visible again for Venus Express 12 hours after MESSENGER’s closest approach, this time on the night-side.

VIRTIS Images of the Clouds That MESSENGER Flew Over

Click image for high resolution copy

Image above: The images in this panel were obtained by the VIRTIS imaging spectrometer on board Venus Express on 5 and 6 June 2007, before and after MESSENGER’s closest approach to the planet. These panels from VIRTIS provide a night-side view of the same region that Messenger flew over and imaged. The images where obtained at 1.7 micrometres, revealing atmospheric details down to an altitude of 50 km from the surface. Credit: NASA/JHUAPL

The VIRTIS imaging spectrometer on board Venus Express probed this cloud (top row of this image composite) at several wavelengths. These observations provided a view of the cloud at about 45-50 km altitude (bottom row) from the planet. The clouds below the point of closest approach can be seen in the top row.

The Mercury Laser Altimeter (MLA) instrument on board MESSENGER probed the same cloud structure at 50-75 km from the surface, like VIRTIS.

Such an observation – a typical example of atmospheric structure at Venus – with cross-sections obtained at different altitudes and with different instruments, is a unique opportunity for researchers hoping to solve the puzzle of the Venusian atmosphere’s dynamics and composition.

Cloud Structures at Venus at Time of MESSENGER Flyby

Image right: This movie consists of a sequence of six images obtained by the VIRTIS imaging spectrometer on board ESA’s Venus Express on 5 and 6 June 2007, before and after NASA MESSENGER’s closest approach to the planet. The image sequence, obtained by VIRTIS, provides a night-side view of the same region that Messenger flew over and imaged. Click image to view animated GIF. Credits: ESA/VIRTIS/INAF-IASF/Obs. de Paris-LESIA

Over about 24 hours, not only did the two spacecraft observe the same clouds, but MESSENGER also flew closely over the atmospheric region. Again, these dual-spacecraft, multi-instrument observations may provide additional atmospheric details.

Thermal and Radar Maps of Venus’ Surface Compared

Image above: An unprocessed thermal map of the Venusian surface obtained by VIRTIS on 5 June 2007 (left) is compared here with a radar image of the same area obtained by NASA’s Magellan spacecraft in the 1990s (right). Correlations between topographic and thermal data similar to the ones shown in this image-composite will allow the scientists to understand if the measured temperature of the surface depends only on the altitude – where higher altitudes simply corresponds to colder, temperatures such as on Earth – or if it depends on the presence of previously undetected sources of heat such as active volcanoes. Credits: Left panel: ESA/VIRTIS/INAF-IASF/Obs. de Paris-LESIA, Right panel: NASA

A spectacular view obtained by VIRTIS (left), in the region of MESSENGER's closest approach to Venus provides, even if still unprocessed, a ‘thermal view’ of the Venusian surface. The image is compared here with an image of the same feature synthesized by data from NASA’s Magellan spacecraft in the 1990s (right).

Magellan provided radar imaging and altimetry maps, providing information on the topography (elevation) and the radar reflectivity of the surface. Venus Express’ VIRTIS is providing ‘thermal maps’ of the surface containing information on the emissivity in the infrared. Correlations between topographic and thermal data similar to the ones shown here, will allow scientists to understand if the measured temperature of the surface depends on the altitude – where ‘higher’ simply corresponds to ‘colder’ – or if it depends on the presence of previously undetected sources of heat, such as active volcanoes or other geological activities.

Image left: ESA’s Venus Express, in orbit around Venus since 11 April 2006, was joined for a few hours by NASA’s MESSENGER spacecraft, flying by Venus while on its way to Mercury. This animation shows both the Venus Express and MESSENGER spacecraft in orbit around Venus at the time of the fly-by. Earth-based observatories and telescopes in orbit around Earth were also watching. Looking at Venus together, spacecraft and ground observatories obtained a unique set of data each, so many different ‘eyes’ observed the same regions and phenomena during the same time frame. Click image to view animation. Credit: NASA/APL

The Venus Express and MESSENGER scientists are now continuing the analysis of this rich and complex set of data collected at Venus. The data also involve several other instruments studying not only Venus’ cloud deck and surface, but also the plasma environment, magnetic fields, and the atmospheric oxygen airglow.

More mature results from this joint observation campaign are expected by the end of the year.


Mike Buckley
Johns Hopkins Applied Physics Lab

07.17.07

Saturn's distinctive moon Iapetus (eye-APP-eh-tuss) is cryogenically frozen in the equivalent of its teenage years. The moon has retained the youthful figure and bulging waistline it sported more than three billion years ago, scientists report.

"Iapetus spun fast, froze young, and left behind a body with lasting curves," said Julie Castillo, Cassini scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif.

Image right: Saturn's moon Iapetus. Image credit: NASA/JPL/Space Science Institute
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Unlike any other moon in the solar system, Iapetus is the same shape today as it was when it was just a few hundred million years old; a well-preserved relic from the time when the solar system was young. These results appear in the online version of the journal Icarus.

Cassini flew by Iapetus in early 2005 and discovered the moon had a walnut shape, bulging at its midsection. On top of that it has a chain of mountains located exactly along its equator.

Scientists now think the moon's bulging midriff and slow spin rate point to heating from long-extinct radioactive elements present when the solar system was born.

"We've modeled how Iapetus formed its big, spin-generated bulge and why its rotation slowed down to its present nearly 80-day period. As an unexpected bonus, Iapetus also told us how old it was," said Dennis Matson, Cassini project scientist at JPL. "You would expect a very fast-spinning moon to have this bulge, but not a slow-spinning moon, because the bulge would have been much flatter."

Scientists calculate Iapetus originally rotated much faster--at least five hours, but less than 16 hours per revolution. The fast spin gave the moon an oblate shape that increased the surface area (in the same way the surface area of a round balloon stretches when the balloon is pressed into an oblate shape). By the time the rotation slowed down to a period of 16 hours, the outer shell of the moon had frozen. Furthermore, the surface area of the cold moon was now smaller. The excess surface material was too rigid to go back smoothly into the moon. Instead, it piled up in a chain of mountains at the equator.

"Iapetus' development literally stopped in its tracks," said Castillo. "In order for tidal forces to slow Iapetus to its current spin rate, its interior had to be much warmer, close to the melting point for water ice."

The challenge in developing a model of how Iapetus came to be "frozen in time" has been in deducing how it ever became warm enough to form a bulge in the first place, and figuring out what caused the heat source to turn off, leaving Iapetus to freeze.

The heat source had to have a limited life span, to allow the moon's crust to rapidly become cold and retain its immature shape. After looking at several models, scientists concluded that the heat came from its rocks, which contain short-lived radioactive isotopes aluminum-26 and iron-60 (which decay very rapidly on a geologic timescale). Since these elements decay at a known rate, this allowed scientists to "carbon date" Iapetus by using aluminum-26 instead of carbon. Scientists calculate the age of Iapetus to be roughly 4.564 billion years old.

Evidence for these same isotopes (aluminum-26 and iron-60) has been found in meteorites formed in the inner solar system. Therefore, there is a possibility of comparing the early chronology of the outer solar system with other objects in the inner solar system, such as Earth, Earth's moon and asteroids.

"This is the first direct evidence of the early spin history for a satellite in the outer solar system. It teaches us more about how the speed of a body's rotation influenced its evolution, and broadens our knowledge of the early history of outer planet satellites," said Matson.

Cassini's next close encounter with Iapetus will occur on Sept. 10, 2007, at 1,000 kilometers (620 miles) from the surface.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington, D.C.

More information on the Cassini mission is available at: http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini .


Media contact: Carolina Martinez 818-354-9382
Jet Propulsion Laboratory, Pasadena, Calif.

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