Thursday, September 30, 2010

Bonobos are close to humans, yet people know very little about them

Primatologist Brian Hare wishes more people could discover what bonobos can teach us about human nature. "I really think they are the smartest ape in the world," he said. "We have a lot to learn from them."

Bonobos are genetically close to humans, yet most people know very little about them. Through his ongoing research, Hare hopes to change that.

"Bonobos really are our less familiar cousins that we have kept at arm's length," Hare said. "The general public is so unfamiliar with them that even many reporters who have interviewed me have written in their stories that they are bonobo 'monkeys,' not realizing they are apes--like us. So it is great when the bonobos can have some attention."

Bonobos are often confused with chimpanzees, but actually are quite different. In looks, bonobos are smaller, with black faces, pink lips and long black hair, neatly parted in the middle. Chimps have low, loud voices, while bonobos' voices are high-pitched.

More significantly, chimps make war, males take charge, and chimps can be quite violent, even to the extent of killing one another. Bonobos, on the other hand, are governed by females, they use sexual activity to maintain a peaceful collective temperament, and scientists have not observed any instances of bonobos killing one another.

Hare, assistant professor of evolutionary anthropology at Duke University, spends several months of the year in the Democratic Republic of Congo, where he studies bonobos. He focuses on their behavior, specifically on how they solve problems and interact with other bonobos.

Recently, he and his colleagues found that bonobos are natural sharers. The researchers' work, published in a recent Current Biology and funded by the National Science Foundation (NSF) and the European Research Council, described how bonobos enjoy sharing food with other bonobos, and never outgrow their willingness to do so--unlike chimpanzees, who become more selfish when they reach adulthood.

In one experiment, the animals in an enclosure were allowed to keep an entire food pile for themselves or open a one-way door that would allow another bonobo to enter the room to eat with them. Invariably, they opened the door.

"What we found is that the bonobos voluntarily chose to open the door for their neighbor so they could share the food," Hare said.

Another set of experiments, at the Tchimpounga Sanctuary in Congo, compared chimpanzees to bonobos. The young chimps were quite similar to young bonobos in their willingness to share food, but researchers discovered that the chimps became less willing to share as they grew older. Bonobos, on the other hand, continued to share like juveniles, even after reaching adulthood, the scientists said.

"It seems like some of these adult differences might actually derive from developmental differences," said Victoria Wobber, a Harvard graduate student who collaborates with Hare. "Evolution has been acting on the development of their cognition."

Hare and his mentor, Richard Wrangham at Harvard, believe bonobos act this way because they always have enjoyed an abundant environment. They typically live south of the Congo River, where there is plenty of food, and where they don't have to compete with gorillas--as chimpanzees must--or with each other.

However, bonobos have human enemies, specifically hunters engaged in the illegal international trade in bush meat. Conservationists are working to rescue bonobos who have been orphaned by these activities, sheltering them in sanctuaries, where they are protected for as long as they live.

"Unfortunately, bonobos are not immune to the bullets of hunters and often fall prey," Hare said. "Their meat is sold in big cities in Congo, but bush meat traders try to sell infants that survive their mothers' deaths as pets. Here in Congo, it is illegal to buy and sell bonobos, so when an infant is discovered in the market, or in the possession of a wildlife trafficker, they are confiscated."

The animals live in a sanctuary called Lola ya Bonobo, located in Les Petites Chutes de la Lukaya, just outside of Kinshasa. "Lola ya Bonobo" means "paradise for bonobos" in Lingala, the main language of Kinshasa.

Lola ya Bonobo cares for more than 60 bonobo orphans. The facility is run by a staff of conservation and welfare experts who "do an amazing job quickly rehabilitating the infant bonobos, so that they quickly recover from the trauma of their capture, and live a very normal and happy life with other bonobos here at the sanctuary," Hare said, adding: "They have a huge 75-acre forest they play in each day."

Many of these rescued bonobos serve as Hare's research subjects. At the sanctuary, Hare and his fellow researchers use experimental techniques to test the bonobos and observe their behavior. "Essentially, we design fun games that the bonobos can play and enjoy, but at the same time, (the games) can reveal how they solve problems," he said. "The study, published in Current Biology, is a great example of how experiments are important to understand the psychology of animals."

After the games, "we let the bonobos back out into their giant outdoor enclosures so they can play with all the other bonobos in the primary tropical forest they live in during the day," Hare added. "Basically, they stay inside for an hour or so, and get a lot of yummy food, and they go back outside."

Born and raised in Atlanta, Ga., Hare, 34, was always interested in animals and biology, so a career studying animal behavior, "comes kind of naturally," he said. He went to Emory University, where, among other things, he studied chimpanzees.

"However, I'd always wanted to study bonobos and compare them to chimpanzees," he said. "I did my Ph.D. work at Harvard with Richard Wrangham, who encouraged me to start working in African sanctuaries, like Lola ya Bonobo. This is exciting because our research dollars go to organizations in ape habitat countries working on welfare and conservation efforts."

Hare's wife, Vanessa Woods, is a research scientist in biological anthropology and anatomy at Duke. She has written a book about the bonobos, Congo and their research on bonobos, entitled "Bonobo Handshake," scheduled to be released in June by Gotham/Penguin. "I do think it could be a great reference if people want to learn more about bonobos," Hare said. "She detailed a lot of the story about our research--maybe too much detail in some places--a good place to look for embarrassing stories."

Lola ya Bonobo is the largest bonobo captive facility in the world that supports research, Hare said, which enables scientists "to do a number of comparisons between chimpanzees and bonobos that would otherwise be impossible."

Hare is especially pleased that one of his research colleagues, Suzy Kwetuenda, based at Lola ya Bonobo, is the first Congolese student ever to study the psychology of bonobos.

"Hopefully, she will be the first of many students studying bonobos' behavior and psychology," added Hare, "and that will get average Congolese citizens excited about saving the bonobo, which is only found in their country."

Lost bugs Found Again in South Dakota

Research entomologist Louis Hesler takes readers along as he and others search for types of ladybugs that were once common but have become extremely rare in eastern North America
I was frustrated. I had been searching for years for the so-called "lost ladybugs," but hadn't found any.

It was 2008, and only a few had been found by anyone in the last three decades, although they were once common in many areas, especially crop fields such as wheat and alfalfa.

There are actually hundreds of kinds of ladybugs, but three in particular--the two-spotted, nine-spotted and transverse ladybugs--seemed to have vanished from the landscape of eastern South Dakota.

Research scientists publish findings from their observations and experiments. So, I began to question myself. "How can I, as a scientist, publish my findings of 'no findings?'" I wondered if maybe my methods and approach were wrong.

I had been working from three hunches about the fate of lost ladybugs. First, maybe the once-common lost ladybugs would recover in abundance on their own, as some populations of insects have rebounded after prolonged periods of sparseness. There was added hope for this since populations of the soybean aphid had recently exploded in soybean fields of the north-central United States, providing a new prey source for ladybugs. Nonetheless, after years of sampling soybean and other crops, I had not found the lost ladybugs.

A second possibility was that lost ladybugs had moved from crop fields to habitats such as prairies, tree belts or weedy patches. At about the time native ladybugs were lost from crop fields, two kinds of ladybugs imported from Eurasia--the seven-spotted and multicolored Asian ladybugs--had become plentiful in fields over much of North America. The apparent aggressiveness of these newly established ladybugs may have forced some of the native ladybugs into non-crop habitat in order to minimize competition. However, despite searching various habitats, I was still unable to detect lost ladybugs.

I then followed up on a notion that the ladybugs may have only been lost locally, and that I could find them by simply surveying a few hundred miles from my workstation. This led my colleagues and me to venture into southeastern North Dakota, Iowa and Minnesota, but sampling again failed to yield any lost ladybugs. More importantly, based on similar surveys by scientists in other regions, there was also increasing alarm that lost ladybugs had become extremely rare throughout eastern North America.

However, a glimmer of hope arose after Robert Kieckhefer, a retired U.S. Department of Agriculture (USDA) entomologist, found two-spotted ladybugs in western South Dakota. This finding sparked a hunch that lost ladybugs might fare better in more arid western North America. So, I called Michael Catangui, an entomologist at South Dakota State University who heads up the National Science Foundation (NSF)- sponsored Lost Ladybug Project with me in South Dakota. Buoyed by Kieckhefer's recent finds, we headed to western South Dakota with sweepnets and other gear to sample for lost ladybugs.

We arrived in the Badlands of western South Dakota on a typical June day--sunny, fairly hot and breezy. We sampled roadside vegetation and various patches of grasses and forbs within and around Badlands National Park, finding various ladybugs but not lost ladybugs.

At sunset, while sampling roadside vegetation near the southern unit of the park, Mike called excitedly to me from about 10 yards away. "Hey, Louis. Come see what I have," referring to the nine-spotted lady beetle he had just found on a curlycup gumweed plant.

"Okay," I replied, "but maybe you should first see what I found," as I carefully teased a nine-spotted lady beetle from gumweed into a container and headed toward Mike.

We fondly remember our simultaneous discoveries. "We had searched for lost ladybugs all day, and been stumped. Then, as daylight was fading, each of us independently found a nine-spotted lady beetle. Remarkable!" Catangui recalls.

Soon afterward, John Losey, the entomologist in charge of the Lost Ladybug Project at Cornell University in Ithaca, N.Y., joined the hunt for lost ladybugs in western South Dakota. John and I found transverse and two-spotted ladybugs at several spots there. That same summer, colleagues conducting grasshopper surveys in western South Dakota found more nine-spotted ladybugs, and I found both transverse and nine-spotted ladybugs during a survey of sites in western Nebraska.

The presence of lost ladybugs in western South Dakota and western Nebraska fits a pattern in which most recent finds have occurred in western states. Many of these recent finds were submitted as digital images by citizen scientists to the Lost Ladybug Project website, run by Losey and colleagues at Cornell. Our recruitment of citizen scientists to the project was paying off. Now, both they and the entomologists on the project were finding lost ladybugs. And my self-doubt had faded as I realized lost ladybugs actually were hard to detect in the east, but could be found in western states.

These findings raise questions as to why lost ladybugs are more easily found in western than eastern parts of North America, and why their populations have declined in general. Entomologists on the Lost Ladybug Project are now avidly seeking answers through field and laboratory experiments.

Sunday, September 26, 2010

As Corals rapidly declining, Scientists Watch for Signs of Evolution

Our oceans are getting warmer and more acidic every year; as a result, coral reefs are rapidly declining. Biologist Mikhail Matz is monitoring this process at the genomic level, in anticipation of evolutionary developments that may signal better news.

"Corals have a substantial potential to evolve, and this is the high time for them to do it," said Matz, assistant professor of integrative biology at the University of Texas at Austin and an expert on coral DNA. "I want to watch them very closely as it happens to see how evolution works."

Only a few years ago, studying an organism like coral through its genes would have been impossible because of the cost and time involved. Now, with the emergence of next-generation gene-sequencing devices, scientists are moving beyond mice, flies and worms--the traditional platforms for DNA research--to study the genetic makeup of a much wider variety of organisms.

In 2009, Matz and his team sequenced the entire transcriptome (the set of all RNA molecules, reflecting the genes at work at a particular moment) of a common Pacific coral for a fraction of the cost of previous efforts. For Matz's purposes, the transcriptome is a better resource than the genome because it provides a concise summary of the information relevant to the study of evolution. Matz's study was one of the first successful full-transcriptome sequences for a novel model organism.

However, sequencing an organism's transcriptome is only the beginning. The next step is interpreting the genetic data to make connections between genes and traits.

"How does the genome drive variation in gene function, and how does it lead to physiological modifications and eventually adaptation to the changing environment?" Matz asked. "We want to forge those links."

Matz is one of the first researchers to use next-generation sequencers to study evolution. In doing so, he is developing a workflow that will allow the broader biological community to use next-generation sequencing effectively.

"Imagine someone having an evolution- or biomedicine-related question that can be best addressed using some obscure marine worm as a model," Matz explained. "We want to show how to do it--basically, how to elevate your favorite worm to the state of full-blown genomic model in a matter of several months."

Perhaps paradoxically, one of the biggest problems for biologists is that next-generation sequencers produce too much data. It takes the Texas Advanced Computing Center's (TACC) Ranger supercomputer, with its massive size and speed, to make full sense of the data. TACC is one of 11 partner sites around the U.S. that compose the TeraGrid. Funded by the National Science Foundation (NSF), TeraGrid is the world's largest, most comprehensive, distributed cyberinfrastructure for open scientific research. Currently, TeraGrid resources include more than a petaflop (a thousand trillion calculations per second) of computing capability and more than 30 petabytes of online and archival data storage, with rapid access and retrieval over high-performance networks.

Matz relies on Ranger's power to experiment with various approaches, select optimal procedures and eventually bring the analysis within the reach of standard desktop computers.

At the same time, Matz continues to analyze the coral results, waiting for the telltale genomic signs of evolution.

"The old corals are dying, yes, but that's a part of evolving. This may be horrible news, or this can be good news, all depending on how the next generation of corals turns out," Matz said. "Once we know how corals evolve, we might be able to help them in this, or at least avoid standing in evolution's way."

Thursday, September 23, 2010

Shuttle Discovery Preparing for Flight

In preparation for its last planned mission to the International Space Station, shuttle Discovery was lowered onto its external fuel tank and solid rocket boosters in High Bay 3 of the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida. The lift and mate operation began Sept. 9 and wrapped up early Sept. 10.

On Sept. 21, 2010, Discovery completed its last planned trip to the launch pad at 1:49 a.m., leaving the Vehicle Assembly Building at about 7:23 p.m. on the slow, 3.4-mile crawl to the pad.

Discovery, the oldest of NASA's three active orbiters, first launched Aug. 30, 1984, on STS-41D and is being readied for the STS-133 mission to station. Liftoff is targeted for Nov. 1 at 4:40 p.m. EDT.

Tuesday, September 21, 2010

Desert Dust Cuts Colorado River Flow

Snow melt in the Colorado River basin is occurring earlier, reducing runoff and the amount of crucial water available downstream. A new study shows this is due to increased dust caused by human activities in the region during the past 150 years.

The study, led by a NASA scientist and funded by the agency and the National Science Foundation, showed peak spring runoff now comes three weeks earlier than before the region was settled and soils were disturbed. Annual runoff is lower by more than five percent on average compared to pre-settlement levels.

The findings have major implications for the 27 million people in the seven U.S. states and Mexico who rely on the Colorado River for drinking, agricultural and industrial water. The results were published in this week's Proceedings of the National Academy of Sciences.

The research team was led by Tom Painter, a snow hydrologist at both NASA's Jet Propulsion Laboratory in Pasadena, Calif., and UCLA. The team examined the impact of human-produced dust deposits on mountain snowpacks over the Upper Colorado River basin between 1915 and 2003. Studies of lake sediment cores showed the amount of dust falling in the Rocky Mountains increased by 500 to 600 percent since the mid-to-late 1800s, when grazing and agriculture began to disturb fragile but stable desert soils.

The team used an advanced hydrology model to simulate the balance of water flowing into and out of the river basin under current dusty conditions, and those that existed before soil was disturbed. Hydrologic data gathered from field studies funded by NASA and the National Science Foundation, and measurements of the absorption of sunlight by dust in snow, were combined with the modeling.

More than 80 percent of sunlight falling on fresh snow is typically reflected back into space. In the semi-arid regions of the Colorado Plateau and Great Basin, winds blow desert dust east, triggering dust-on-snow events. When dark dust particles fall on snow, they reduce its ability to reflect sunlight. The snow also absorbs more of the sun's energy. This darker snow cover melts earlier, with some water evaporating into the atmosphere.

Earlier melt seasons expose vegetation sooner, and plants lose water to the atmosphere through the exhalation of vapor. The study shows an annual average of approximately 35-billion cubic feet of water is lost from this exhalation and the overall evaporation that would otherwise feed the Colorado River. This is enough water to supply Los Angeles for 18 months.

"The compressed mountain runoff period makes water management more difficult than a slower runoff," Painter said. "With the more rapid runoff under dust-accelerated melt, costly errors are more likely to be made when water is released from and captured in Colorado River reservoirs."

Prior to the study, scientists and water managers had a poor understanding of dust-on-snow events. Scientists knew from theory and modeling studies that dust could be changing the way snowfields reflect and absorb sunlight, but no one had measured its full impact on snowmelt rates and runoff over the river basin. The team addressed these uncertainties by making systematic measurements of the sources, frequency and snowmelt impact of dust-on-snow events.

"These researchers brought together their collective expertise to provide a historical context for how the Colorado River and its runoff respond to dust deposition on snow," said Anjuli Bamzai, program director in the National Science Foundation's Division of Atmospheric and Geospace Sciences in Arlington, Va. "The work lays the foundation for future sound water resource management."

Painter believes steps can be taken to reduce the severity of dust-on-snow events in the Colorado River basin. He points to the impact of the Taylor Grazing Act of 1934 for potential guidance on how dust loads can be reduced. The act regulated grazing on public lands to improve rangeland conditions. Lake sediment studies show it decreased the amount of dust falling in the Rocky Mountains by about one quarter.

"Restoration of desert soils could increase the duration of snow cover, simplifying water management, increasing water supplies and reducing the need for additional reservoir storage of water. Peak runoff under cleaner conditions would then come later in summer, when agricultural and other water demands are greater," Painter said.

"It could also at least partially mitigate the expected regional impacts of climate change, which include reduced Colorado River flows, increased year-to-year variability in its flow rate, and more severe and longer droughts," he added. "Climate models project a seven to 20 percent reduction in Colorado River basin runoff in this century due to climate change."

Other institutions participating in the study include the National Snow and Ice Center in Boulder, Colo.; U.S. Geological Survey Southwest Biological Center in Moab, Utah; University of Washington in Seattle; Center for Snow and Avalanche Studies in Silverton, Colo.; and the University of Colorado-NOAA Western Water Assessment in Boulder.

Thursday, September 16, 2010

ARTEMIS - The First Earth-Moon Libration Orbiter

In August 1960, NASA launched its first communications satellite, Echo 1. Fifty years later, NASA has achieved another first by placing the ARTEMIS-P1 spacecraft into a unique orbit behind the moon, but not actually orbiting the moon itself. This type of orbit, called an Earth-Moon libration orbit, relies on a precise balancing of the Sun, Earth, and Moon gravity so that a spacecraft can orbit about a virtual location rather than about a planet or moon. The diagrams below show the full ARTEMIS-P1 orbit as it flies in proximity to the moon.

ARTEMIS-P1 is the first spacecraft to navigate to and perform stationkeeping operations around the Earth-Moon L1 and L2 Lagrangian points. There are five Lagrangian points associated with the Earth-Moon system. The two points nearest the moon are of great interest for lunar exploration. These points are called L1 (located between the Earth and Moon) and L2 (located on the far side of the Moon from Earth), each about 61,300 km (38,100 miles) above the lunar surface. It takes about 14 to 15 days to complete one revolution about either the L1 or L2 point. These distinctive kidney-shaped orbits are dynamically unstable and require weekly monitoring from ground personnel. Orbit corrections to maintain stability are regularly performed using onboard thrusters.

After the ARTEMIS-P1 spacecraft has completed its first four revolutions in the L2 orbit, the ARTEMIS-P2 spacecraft will enter the L1 orbit. The two sister spacecraft will take magnetospheric observations from opposite sides of the moon for three months, then ARTEMIS-P1 will move to the L1 side where they will both remain in orbit for an additional three months. Flying the two spacecraft on opposite sides, then the same side, of the moon provides for collection of new science data in the Sun-Earth-Moon environment. ARTEMIS will use simultaneous measurements of particles and electric and magnetic fields from two locations to provide the first three-dimensional perspective of how energetic particle acceleration occurs near the Moon's orbit, in the distant magnetosphere, and in the solar wind. ARTEMIS will also collect unprecedented observations of the space environment behind the dark side of the Moon – the greatest known vacuum in the solar system – by the solar wind. In late March 2011, both spacecraft will be maneuvered into elliptical lunar orbits where they will continue to observe magnetospheric dynamics, solar wind and the space environment over the course of several years.

ARTEMIS stands for “Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon’s Interaction with the Sun”. The ARTEMIS mission uses two of the five in-orbit spacecraft from another NASA Heliophysics constellation of satellites (THEMIS) that were launched in 2007 and successfully completed their mission earlier this year. The ARTEMIS mission allowed NASA to repurpose two in-orbit spacecraft to extend their useful science mission, saving tens of millions of taxpayer dollars instead of building and launching new spacecraft. Other benefits of this first ever libration orbit mission include the investigation of lunar regions to provide a staging location for both assembly of telescopes or human exploration of planets and asteroids or even to serve as a communication relay location for a future lunar outpost. The navigation and control of the spacecraft will also provide NASA engineers with important information on propellant usage, requirements on ground station resources, and the sensitivity of controlling these unique orbits.

The ARTEMIS mission implementation and operation represents a joint effort between NASA Goddard Space Flight Center in Greenbelt, Md., the Jet Propulsion Laboratory in Calif., and the University of California, Berkeley, Space Sciences Laboratory.

Sunday, September 12, 2010

NASA's Phoenix Shed New Light About Water and Volcanoes on Mars

Data from NASA's Phoenix Mars Lander suggest liquid water has interacted with the Martian surface throughout the planet's history and into modern times. The research also provides new evidence that volcanic activity has persisted on the Red Planet into geologically recent times, several million years ago.

Although the lander, which arrived on Mars on May 25, 2008, is no longer operating, NASA scientists continue to analyze data gathered from that mission. These recent findings are based on data about the planet's carbon dioxide, which makes up about 95 percent of the Martian atmosphere.

"Atmospheric carbon dioxide is like a chemical spy," said Paul Niles, a space scientist at NASA's Johnson Space Center in Houston. "It infiltrates every part of the surface of Mars and can indicate the presence of water and its history."

Phoenix precisely measured isotopes of carbon and oxygen in the carbon dioxide of the Martian atmosphere. Isotopes are variants of the same element with different atomic weights. Niles is lead author of a paper about the findings published in Thursday's online edition of the journal Science. The paper explains the ratios of stable isotopes and their implications for the history of Martian water and volcanoes.

"Isotopes can be used as a chemical signature that can tell us where something came from, and what kinds of events it has experienced," Niles said.

This chemical signature suggests that liquid water primarily existed at temperatures near freezing and that hydrothermal systems similar to Yellowstone's hot springs have been rare throughout the planet's past. Measurements concerning carbon dioxide showed Mars is a much more active planet than previously thought. The results imply Mars has replenished its atmospheric carbon dioxide relatively recently, and the carbon dioxide has reacted with liquid water present on the surface.

Measurements were performed by an instrument on Phoenix called the Evolved Gas Analyzer. The instrument was capable of doing more accurate analysis of carbon dioxide than similar instruments on NASA's Viking landers in the 1970s. The Viking Program provided the only previous Mars isotope data sent back to Earth.

The low gravity and lack of a magnetic field on Mars mean that as carbon dioxide accumulates in the atmosphere, it will be lost to space. This process favors loss of a lighter isotope named carbon-12 compared to carbon-13. If Martian carbon dioxide had experienced only this process of atmospheric loss without some additional process replenishing carbon-12, the ratio of carbon-13 to carbon-12 would be much higher than what Phoenix measured. This suggests the Martian atmosphere recently has been replenished with carbon dioxide emitted from volcanoes, and volcanism has been an active process in Mars' recent past. However, a volcanic signature is not present in the proportions of two other isotopes, oxygen-18 and oxygen-16, found in Martian carbon dioxide. The finding suggests the carbon dioxide has reacted with liquid water, which enriched the oxygen in carbon dioxide with the heavier oxygen-18.

Niles and his team theorize this oxygen isotopic signature indicates liquid water has been present on the Martian surface recently enough and abundantly enough to affect the composition of the current atmosphere. The findings do not reveal specific locations or dates of liquid water and volcanic vents, but recent occurrences of those conditions provide the best explanations for the isotope proportions.

Tuesday, September 07, 2010

Kepler Mission Update

The Kepler team continues with its very busy operations and data analysis activities. Monthly science data downloads were successfully completed in July and August 2010 on schedule. These downloads represented Quarter 6, Months 1 and 2, of the Kepler mission data set. Project management and engineers recently gathered to assess Kepler flight system performance since operations began on May 12, 2009. Spacecraft subsystem engineers presented data summaries and analyses on several functional areas: power, thermal, attitude determination and control, telecommunications, avionics, propulsion and photometer. These engineers were able to see how their systems performed over a Kepler year (371 days), and even a bit of an overlap with the beginning of year 2.

During the course of a Kepler Year, several changes occur. As the spacecraft orbits the sun, while maintaining the telescope pointed at the science field of view, the sun position changes on the solar panels, changing the solar array output. As equipment moves in and out of the sun, heaters go on and off to maintain stable temperatures. The star trackers, which are used for coarse attitude control, use different stars each season. The relative angles to the Earth also change throughout each quarter, causing the telecom signal levels to change. All these things can change the spacecraft’s performance. In addition, with the year 2 overlap, we are able to see how performance has changed since we were at the same conditions as we were one year ago.

In general, predictions were close to actual flight performance for all systems. The power systems (solar panels and battery) have performed somewhat better than expected. Thermal analysis shows the spacecraft is a bit warmer than expected in some areas, probably due to some initial degradation of the surfaces exposed to the sun, but well within expected ranges and all heaters are working well. Since the flight software and star tracker patches that were made in April 2010, the ADCS system has been nominal and the fine pointing control used in science observations are well below the required accuracy and stability requirements.

The telecom system has been performing without problems and is matching predicted performance levels. Kepler is the first mission that uses Ka-Band to downlink science data and we have been very pleased with both our spacecraft performance and that of the Deep Space Network operations. We have been able to communicate with the spacecraft at lower elevation angles than initially planned, and the data drop-out rate has been very small. Avionics have been working well, with good margins on processing capacity.

The propulsion system on Kepler is used about once every 3 days to spin down the reaction wheels that are used to maintain attitude control. Analysis shows that we are using slightly less propellant to do this than our conservative, pre-launch models. The photometer continues to work well and although one module failed back in January 2010, we still exceed the requirement for field of view.

Predictions for the rest of the mission are all positive, and we see nothing that would cause us to change our operating plans. The only expendable resource we have on Kepler is propellant, and estimates are that we have sufficient propellant for another 10 years (well above the 2.5 years remaining in the nominal mission). Currently our most challenging issue as we look out in the long term, is the telecom margin as the spacecraft gets further from the Earth. We will have to continue to drop our data rate over time, as the signal strength drops due to distance. Overall, the project is quite pleased with the spacecraft's performance so far.

Meanwhile, the Kepler Science Team has been quite busy analyzing all the data Kepler has collected to date. There are many planetary candidates that the team must assess and verify as a true planet or a false signature. As you know, the Kepler Mission has a primary goal of measuring the brightnesses of 100,000+ stars with unprecedented precision. If an Earth-sized planet orbits in front of a sun-like star, the blocking of the starlight causes the star to dim over and over, allowing Kepler to detect the planet. The bigger the planet, the more light it blocks, allowing the Kepler team to determine the diameter of the planet.

Such a discovery is called a "planet candidate" because it has not yet been verified as a true planet. If it isn't a planet, why does the star appear to dim, over and over? One nagging possibility is that behind the star are two additional stars that orbit each other, eclipsing themselves when they cross in front of each other. Such a background "eclipsing binary star" would dim once per orbit, mimicking the dimming signature of a planet. In that case, the "planet candidate" would not be a planet at all. We would be fooled. With hundreds of planet candidates emerging from Kepler, as announced in June 2010, the challenge of weeding out the eclipsing binary stars from the bona fide planets is a daunting task.

The Kepler Mission assesses these false planets with its "Follow-up Observing Program" (FOP) designed to distinguish true planets from the imposters. The FOP consists of 15 team members, each with different expertise in different methods of identifying pesky eclipsing binary stars. The first approach is to obtain high quality pictures of the field of stars around the main stars. The FOP takes images of the field surrounding Kepler stars using a 1-meter telescope at Lick Observatory, 2-meter telescopes operated by the Las Cumbres Observatory, and even the Keck telescope in Hawaii for the highest priority stars. So far the FOP has obtained images of over 400 Kepler stars. To obtain more detailed images, the FOP uses the adaptive optics system on the 5-meter Palomar telescope and the MMT telescope on Mt. Hopkins. Adaptive optics can take pictures capable of detecting any eclipsing binary located exceedingly close to the star. Any star showing no eclipsing binary by adaptive optics is unlikely to have one still hiding, by chance, behind the glare of the star.

Another way the FOP weeds out eclipsing binary star is by taking a "reconnaissance" spectrum of the star. Using telescopes with 3-meter diameter mirrors at Mt. Hopkins, McDonald, Lick and the Canary Islands observatories, the light of a star can be spread out with a spectrometer into the colors (i.e. wavelengths) of which the light is composed. Eclipsing binary stars reveal themselves by the two distinct rainbows of colors they each produce, painted one on top of the other, but displaced from each other by the Doppler Effect. The Doppler effect is what allows a police officer to detect a speeding car on the highway. An eclipsing binary star would exhibit two different speed readings in its spectrum of colors, betraying the existence of two orbiting stars whizzing around each other. The reconnaissance spectrum also permits the FOP to determine how many "spectral lines" the star has and how sharp those lines are. Spectral lines are light at a particular frequency, just as a piano has notes of a particular frequency. The spectral lines come from atoms in the star’s atmosphere, and a large number of lines and their sharpness offers a chance to measure the Doppler effect with extreme precision, measuring the speed of the star to within human walking speed. Indeed, the highest priority planet candidates (those nearly Earth-sized) are then observed with the Keck telescope in Hawaii with its "HIRES" spectrometer, with the goal of measuring the Doppler Effect with extreme precision of one meter per second. A planet will pull gravitationally on its host star, yanking it to and fro, and such motion of the star can be detected by the changing Doppler effect. Thus, the planet candidate can be certified as a bona fide planet by detecting the orderly "wobble" of the star as seen in the continuously oscillating Doppler effect.

Moreover, the Kepler FOP measures the amount of Doppler effect of the star. The more massive the planet, and greater the gravitational tug on the host star. So the FOP can use the amount of Doppler effect of the star to measure the mass of the planet. This is a glorious achievement, as the dimming measured by Kepler gives us the planet's diameter, while the Doppler effect gives us the planet's mass. The beauty of this is that we can directly determine the density of the planet, which is its mass divided by its volume. Planets like Earth have the high density of rock, about 5 grams per cubic centimeter, while gaseous planets like Jupiter have much lower densities of about 1 gram per cubic centimeter. The FOP measurement of the planet's density allows the Kepler team to distinguish true rocky planets, like Earth, from gaseous planets, like Jupiter.

The FOP has its work cut out for it. With hundreds of candidate planets from Kepler, there are thousands of imaging and spectroscopic observations that must be made. The FOP scientists are incredibly hard-working, spending hundreds of long nights at telescopes around the world. The two goals of the FOP are crucial to the Kepler mission, namely to weed out the eclipsing binary stars that mimic planets and to measure the masses of the credentialed planets. So far, many hundreds of images and over 700 spectra have already been taken of the Kepler planet candidates. A dozen eclipsing binaries have indeed been found, cleansing them from the planet candidates that Kepler continues to pursue. In the end, Kepler plus the FOP will provide the hard data that secure the discovery of Earth-sized planets around other stars.

Monday, September 06, 2010

NASA Watching Storms in the Atlantic and the Pacific

NASA satellites and the International Space Station are keeping eyes on Hurricane Earl as it heads for New England. Watches and Warnings are posted in the U.S. northeast.

Having felt the effects of both increasing wind shear and cooler waters, Hurricane Earl weakened to a Category 2 storm on the Saffir-Simpson scale with winds still powerful at 90 knots (104 mph) as it neared the North Carolina coast. It was at this time that the Tropical Rainfall Measuring Mission (TRMM) satellite captured the data about TRMM's rainfall rates.

The rainfall pattern associated with Earl and was made using data from the TRMM satellite when it flew over the storm on September 3 at 08:22 UTC (4:22 a.m. EDT). Rainbands from Earl were visible over the outer banks, eastern North Carolina, and southeastern Virginia, but the storm no longer has a well-defined eye. TRMM observed moderate rainfall mostly to the north of Earl's center.

Meanwhile, from a second vantage point in space, at the International Space Station, Astronaut Douglas Wheelock caught an image of the eye of the storm on September 3. As the ISS flew over Hurricane Earl Wheelock noted that it looked like magnificent chaos from up there on the Space Station and called it incredibly breathtaking.

At 11 a.m. EDT on Sept. 3, Hurricane Earl's maximum sustained winds were near 85 mph. It was located about 350 miles south-southwest of Nantucket, Mass. near 36.8 North and 73.1 West. Earl's minimum central pressure was 961 millibars, and he was moving north-northeast at 21 mph.

Because Earl is now forecast to track farther away from the coast, many of the watches and warnings have been discontinued, but new watches and warnings are in place. The current watches and warnings in effect include: a hurricane warning is in effect for Woods Hole eastward around Cape Cod to Sagamore Beach Massachusetts, including Marthas Vineyard and Nantucket Island. In addition a Hurricane Watch is now in effect for Nova Scotia, Canada from Ecum Secum westward to Digby.

Earl is expected to weaken further as it continues northward over cooler waters along the Eastern Seaboard. Updates on Earl are available through the National Hurricane Center at www.nhc.noaa.govand through the NASA Hurricane twitter page.

Hurricane Earl lashed the North Carolina coast last night and this morning, September 3, and is now headed for Cape Cod, Massachusetts. This morning's image from the GOES-13 satellite saw Hurricane Earl's clouds covering most of the northeastern U.S.

The Geostationary Operational Environmental Satellite known as GOES-13 captured an image of Hurricane Earl at 7:32 a.m. EDT this morning, September 3. The image clearly showed a huge Hurricane Earl northeast of North Carolina with cloud cover stretching over the northeastern U.S. A disorganized Fiona was also seen southeast of Earl near Bermuda. GOES satellites are operated by NOAA, and images and animations are created by the NASA GOES Project at the NASA Goddard Space Flight Center, Greenbelt, Md.

Hurricane Warnings and Watches and Tropical Storm Warnings and Watches were in effect today from North Carolina to Massachusetts. For all warnings, visit:

At 8 a.m. EDT today, Earl was a Category 2 hurricane on the Saffir-Simpson scale with maximum sustained winds near 105 with higher gusts. Hurricane force winds extend outward up to 70 miles from the center and tropical storm force winds extend outward up to 205 miles.

At 8 a.m. EDT Dare County (North Carolina) regional airport North Carolina reported a wind gust to 70 mph. Estimated minimum central pressure is 955 Millibars.

The National Weather Service forecast for Nags Head, North Carolina for Friday calls for "Tropical storm conditions expected, with hurricane conditions possible. Showers, mainly before 11am with a high near 87. Northwest wind 45 to 55 mph decreasing to between 25 and 30 mph. Winds could gust as high as 75 mph." Nags Head is currently under a hurricane warning.

Earl is about 130 miles east-northeast of Cape Hatteras, North Carolina and 395 miles south-southwest of Nantucket, Mass., near 36.2 North and 73.6 West. It was moving north-northeast near 18 mph and is expected to turn toward the northeast between 8 p.m. EDT tonight and 8 a.m. EDT on Saturday. Earl will approach southeastern New England tonight.

Thursday, September 02, 2010

NASA's Spitzer Space Telescope reveals a Flavorful Mix of Asteroids

New research from NASA's Spitzer Space Telescope reveals that asteroids somewhat near Earth, termed near-Earth objects, are a mixed bunch, with a surprisingly wide array of compositions. Like a piñata filled with everything from chocolates to fruity candies, these asteroids come in assorted colors and compositions. Some are dark and dull; others are shiny and bright. The Spitzer observations of 100 known near-Earth asteroids demonstrate that the objects’ diversity is greater than previously thought.

The findings are helping astronomers better understand near-Earth objects as a whole -- a population whose physical properties are not well known.

"These rocks are teaching us about the places they come from," said David Trilling of Northern Arizona University, Flagstaff, lead author of a new paper on the research appearing in the September issue of Astronomical Journal. "It's like studying pebbles in a streambed to learn about the mountains they tumbled down."

After nearly six years of operation, in May 2009, Spitzer used up the liquid coolant needed to chill its infrared detectors. It is now operating in a so-called "warm" mode (the actual temperature is still quite cold at 30 Kelvin, or minus 406 degrees Fahrenheit). Two of Spitzer's infrared channels, the shortest-wavelength detectors on the observatory, are working perfectly.

One of the mission's new "warm" programs is to survey about 700 near-Earth objects, cataloguing their individual traits. By observing in infrared, Spitzer is helping to gather more accurate estimates of asteroids' compositions and sizes than what is possible with visible light alone. Visible-light observations of an asteroid won't differentiate between an asteroid that is big and dark, or small and light. Both rocks would reflect the same amount of visible sunlight. Infrared data provide a read on the object's temperature, which then tells an astronomer more about the actual size and composition. A big, dark rock has a higher temperature than a small, light one because it absorbs more sunlight.

Trilling and his team have analyzed preliminary data on 100 near-Earth asteroids so far. They plan to observe 600 more over the next year. There are roughly 7,000 known near-Earth objects out of a population expected to number in the tens to hundreds of thousands.

"Very little is known about the physical characteristics of the near-Earth population," said Trilling. "Our data will tell us more about the population, and how it changes from one object to the next. This information could be used to help plan possible future space missions to study a near-Earth object."

The data show that some of the smaller objects have surprisingly high albedos (an albedo is a measurement of how much sunlight an object reflects). Since asteroid surfaces become darker with time due to exposure to solar radiation, the presence of lighter, brighter surfaces for some asteroids may indicate that they are relatively young. This is evidence for the continuing evolution of the near-Earth object population.

In addition, the fact that the asteroids observed so far have a greater degree of diversity than expected indicates that they might have different origins. Some might come from the main belt between Mars and Jupiter, and others could come from farther out in the solar system. This diversity also suggests that the materials that went into making the asteroids -- the same materials that make up our planets -- were probably mixed together like a big solar-system soup very early in its history.

The research complements that of NASA's Wide-field Infrared Survey Explorer, or WISE, an all-sky infrared survey mission also up in space now. WISE has already observed more than 430 near-Earth objects -- of these, more than 110 are newly discovered.

In the future, both Spitzer and WISE will tell us even more about the "flavors" of near-Earth objects. This could reveal new clues about how the cosmic objects might have dotted our young planet with water and organics -- ingredients needed to kick-start life.

Other authors of the paper include Cristina Thomas, also from Northern Arizona University; Michael Mueller and Marco Delbo of the Observatoire de la Côte d'Azur, Nice, France; Joseph Hora, Giovanni Fazio, Howard Smith and Tim Spahr of the Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass.; Alan Harris of the DLR Institute of Planetary Research, Berlin, Germany (DLR is Germany's space agency and stands for Deutsches Zentrum für Luft- und Raumfahrt); Bidushi Bhattacharya of the NASA Herschel Science Center at the California Institute of Technology, Pasadena; Steve Chesley and Amy Mainzer of NASA's Jet Propulsion Laboratory, Pasadena, Calif.; Bill Bottke of the Southwest Research Institute, Boulder, Colo.; Josh Emery of the University of Tennessee, Knoxville; Bryan Penprase of the Pomona College, Claremont, Calif.; and John Stansberry of the University of Arizona, Tucson.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology, also in Pasadena. Caltech manages JPL for NASA. For more information about Spitzer, visit and .