Day 50

Simulation of a pandemic flu outbreak in the continental United States, initially introduced by the arrival of 10 infected individuals in Los Angeles. The spatiotemporal dynamics of the prevalence (number of symptomatic cases at any point in time), is shown on a logarithmic color scale, from 1 or fewer (blue) to 100 or more (red) cases per 1,000 persons. Without vaccination, antiviral drugs, or other mitigation strategies, the entire nation becomes infected within a few months. Depending on the reproductive number R0, effective intervention strategies including vaccination and targeted antiviral prophylaxis can be successful without resorting to economically damaging measures like school closure, quarantine, and work or travel restrictions. This large-scale agent-based simulation involves 280 million people, and uses demographic and worker flow data at the Census tract level, as well as long-range travel statistics, to describe the geographic movement of people. In this simulation, long-range travel is assumed to occur at a lower-than-normal rate (10 percent) due to travel advisories, but with no other mitigation strategies the pandemic quickly spreads nationwide, peaking about 90 days after the initial introduction. Blue = Few or none of the population is showing symptoms, more precisely 1 or fewer per 1000 persons. Green = 50 per 1,000 Red + 100 or more cases per 1,000 persons [Timothy C. Germann, Kai Kadau, Catherine A. Macken (Los Alamos National Laboratory); Ira M. Longini Jr. (Emory University)] Full size illustrations and QuickTime Animation available here.

Day 90

A tax credit for facilities used to manufacture or distribute, or for R&D on, a qualified product.

Manufacturers of qualified products may take a tax credit on research expenses.
IDSA also supports several other steps to strengthen infectious diseases legislation, including:

Granting a "priority review voucher" to a company that develops a qualified product. The company can use that voucher to speed FDA review of another product, or it could sell the voucher to another company.

Extending the patent term on antibiotics and other anti-infectives--a controversial proposal, but one for which the time has come.

Doubling CDC's antimicrobial resistance funding to $50 million in fiscal year 2007.

The need for new tools to fight infectious diseases is urgent. Antimicrobial resistance is growing, and many experts believe we are overdue for an influenza pandemic. Dr. Blaser concluded, "These bad bugs will not wait, and neither can we."

Infectious Diseases Society of America - http://www.idsociety.org

Simulation Predicts US Infection
DOE/Los Alamos National Laboratory News Release

LOS ALAMOS April 3, 2006 - Using supercomputers to respond to a potential national health emergency, scientists have developed a simulation model that makes stark predictions about the possible future course of an avian influenza pandemic, given today’s environment of world-wide connectivity.

The research, by a team of scientists from Los Alamos National Laboratory in New Mexico, the University of Washington and the Fred Hutchinson Cancer Research Center in Seattle, is presented in the Proceedings of the National Academy of Science online the week of April 3-7, and in the print issue of April 11.

The large-scale, stochastic simulation model examines the nationwide spread of a pandemic influenza virus strain, such as an evolved avian H5N1 virus, should it become transmissible human-to-human.

The simulation rolls out a city- and census-tract-level picture of the spread of infection through a synthetic population of 281 million people over the course of 180 days, and examines the impact of interventions, from antiviral therapy to school closures and travel restrictions, as the vaccine industry struggles to catch up with the evolving virus.

“Based on the present work ... we believe that a large stockpile of avian influenza-based vaccine containing potential pandemic influenza antigens, coupled with the capacity to rapidly make a better-matched vaccine based on human strains, would be the best strategy to mitigate pandemic influenza,” say the authors, Timothy Germann, Kai Kadau, Ira Longini and Catherine Macken.

Longini is a biostatistician with the Fred Hutchinson Cancer Research Center and the University of Washington, while the rest of the team is at Los Alamos. Their collaboration is supported by grants from the Department of Homeland Security and the National Institute of General Medical Sciences MIDAS (Models of Infectious Disease Agent Study) program.

“It's probably not going to be practical to contain a potential pandemic by merely trying to limit contact between people (such as by travel restrictions, quarantine or even closing schools), but we find that these measures are useful in buying time to produce and distribute sufficient quantities of vaccine and antiviral drugs,” said Germann of Los Alamos’ Applied Physics Division.

“Based on our results, combinations of mitigation strategies such as stockpiling vaccines or antiviral agents, along with social distancing measures could be particularly effective in slowing pandemic flu spread in the U.S.,” added Longini.

The results show that advance preparation of a modestly effective vaccine in large quantities appears to be preferable to waiting for the development of a well-matched vaccine that may not become available until a pandemic has already reached the United States.

“Because it is currently impossible to predict which of the diverging strains of avian H5N1 influenza virus is most likely to adapt to human transmission, studies of broadly cross-reactive avian-influenza based vaccines with even modest immunogenicity in humans are important,” said Macken, an influenza researcher in the Los Alamos Theoretical Division. Ideally, both vaccine strategies would be done in parallel: Stockpile a modestly effective vaccine to use while the better-matched one is being developed, the authors suggest.

How it all computes

The computer simulation models a synthetic population that matches U.S. census demographics and worker mobility data by randomly assigning the simulated individuals to households, workplaces, schools, and the like. Department of Transportation travel data is used to model long-distance trips during the course of the simulation, realistically capturing the spread of the pandemic virus by airplane and other passenger travel across the United States.

“In the highly mobile U.S. population, travel restrictions alone will not be enough to stop the spread; a mixture of many mitigation strategies is more likely to be effective than a few strictly enforced ones,” said Kadau, also of Los Alamos’ Theoretical Division.

The model of disease transmission involves probabilities that any two people in a community will meet on any given day in any one of a number of settings, such as home or workplace. Thus, simulated disease transmission is more likely for two people in the same household and less likely for two people who have less in common. “So we are only computing the probability of any person becoming infected on any given day, and a roll of the dice is needed to decide whether they are infected or not,” said Germann.

Other elements of randomness modify the simulated disease course. A significant fraction of infected people (33 percent in the present model) never develop clinical symptoms, although they are themselves infectious. In addition, the durations of the incubation and infectious periods can vary and are randomly chosen from distribution functions for each individual, involving more throws of the virtual dice.

“Computer models serve as virtual laboratories where researchers can study how infectious diseases might spread and what intervention strategies may lessen the impact of a real outbreak,” said Jeremy M. Berg, director of the National Institute of General Medical Sciences. “This new work exemplifies the power of such models and could aid policymakers and health officials as they plan for a possible future pandemic.”

The pandemic simulation model has been implemented in the Laboratory’s celebrated Scalable Parallel Short-range Molecular dynamics (SPaSM) large-scale simulation platform developed for the nuclear weapons program.

It runs on the Los Alamos supercomputer known as Pink, a 1,024-node (2,048 processor) LinuxBIOS/BProc “Science Appliance” running Clustermatic 3, the largest single-system image Linux cluster in the world. Pink's nodes have dual 2.4 GHz Intel Xeon processors (Pentium 4) with 2 gigabytes of memory per node.

The purchase of the Science Appliance was funded by the National Nuclear Security Administration's Advanced Simulation and Computing program. Pink is currently a system software research platform, a science appliance cluster concept invented at Los Alamos in the Computer and Computational Science Division. Los Alamos has four science appliance clusters in use at this time for a variety of projects across the full range of Laboratory mission areas.

The text of the NIGMS press release can be accessed at http://www.nigms.nih.gov/News/Results/FluModel040306

Color illustration of new parrot and mouse. (FM)

Field Museum News Release

CHICAGO April 5, 2006 - Scientists have discovered two new species -- a parrot and a mouse -- that live only on a small island in the Philippines. This island, Camiguin, is the smallest Philippine island, of which there are 7,000, known to support a bird or mammal species that is endemic (lives nowhere else).

The scientists' research, which is embargoed, is described in the April 5 issue of Fieldiana: Zoology, a peer-reviewed, scientific journal about biodiversity research published by The Field Museum.

These new discoveries and the biological diversity they document strengthen the case for preserving the small area of natural rain forest still found on the island.

"Knowing that at least 54 species of birds and at least 24 species of mammals live on Camiguin, and that some of these animals are found nowhere else on earth, makes us realize how important this island is in terms of conservation," said Lawrence Heaney, Curator of Mammals, at The Field Museum and a co-author of several of the reports in this publication. "For these animals to survive, we've got to save the dwindling forests where they live."

The island was once almost entirely covered by rain forest, but by 2001 only 18% was still forested, Heaney said. That amount has dropped since then, as logging, agriculture and human settlement have continued to erode the forests. In fact, almost half the island is now covered with coconut plantations.

"The Philippines is increasingly recognized as a global center for biodiversity, with exceptionally high levels of endemism," said Blas Tabaranza Jr., Director of the Terrestrial Ecosystems Project of the Haribon Foundation, a Philippine conservation NGO based in Manila, and a co-author of several of the Fieldiana reports. "Unfortunately, the Philippines has also vaulted into notoriety as one of the most severely deforested tropical countries in the world."

The scientists have declared Camiguin's rain forest to be a key global conservation priority. Efforts to protect the remaining rain forest in which these animals live as a national park have been underway for several years, in collaboration between The Field Museum, Haribon Foundation, local government, and Philippine Department of Environment and Natural Resources.

Camiguin's forests are not only necessary to protect endangered wildlife, such as the two newly discovered endemic species. They are also essential for the ecotourism that provides much of the island's income. In addition, the forests provide ecological support for the coral reefs surrounding the island that require low levels of runoff and siltation.

According to Tabaranza, the rain forest protects watersheds on the island's steep slopes, helping to control soil erosion and prevent landslides. In February 2006, a mudslide on denuded slopes on the neighboring island of Leyte virtually obliterated the farming village of Guinsaugon and killed an estimated 1,500 residents.

Camiguin is only 102 square miles (265 square kilometers). It has been continuously isolated from its neighbors, even during the Ice Ages of the Pleistocene, when sea levels dropped to 130 yards (120 meters) below present levels. This isolation contributed to the differentiation of the island's animals.

The parrot is a Hanging-parrot, or Colasisi, with bright green feathers covering most of the body (FM)

Detective work

The two new species were discovered as the result of recent and earlier field studies.

The parrot is a Hanging-parrot, or Colasisi, with bright green feathers covering most of the body. The throat and thighs are bright blue, and the top of the head and tail are brilliant scarlet-orange. Males and females have identical plumage, which is quite unusual in this group of parrots.

The description is based on previously unstudied specimens in The Field Museum and the Delaware Museum of Natural History collected in the 1960's by D. S. Rabor. The name for the new species is Loriculus camiguinensis, or Camiguin Hanging-parrot.

"This description is based on a series of specimens that had been part of The Field Museum's collections for almost 40 years, so our work highlights the value of collecting and preserving scientific specimens, because you may not initially realize the significance of specimens," said John Bates, Curator of Birds and Chair of Zoology at The Field Museum, and a co-author of one of the Fieldiana reports. "If we did not have a series of specimens from Camiguin and additional series of Hanging-parrots from other Philippine Islands, we probably would have assumed that the single bird that prompted our investigation was just odd looking, and we would not have been able to recognize it as distinctive."

One of L. camiguinensis' characteristics that was key to identifying it as a new species is the fact that its plumage is relatively dull compared to other Philippine Hanging-parrots. This is consistent with the documented tendency for some isolated bird populations to lose bright plumage, the authors note.

Because L. camiguinensis has not been recognized as a separate species, little is known about its habits, and it has been overlooked in terms of conservation. The discovery has spurred interest in the field studies needed to establish the population size and requirements as a prerequisite for conservation planning and action.

After learning about the Fieldiana manuscript, Thomas Arndt, a German parrot enthusiast, made a trip to Camiguin to look for these birds. He photographed the parrots and is preparing a publication about his findings.

The new mammal is a Philippine forest mouse, now identified as Apomys camiguinensis. It has large ears and eyes, a long tail and rusty-brown fur, and it feeds mostly on insects and seeds. The description is based on mice captured on Camiguin during a biological survey Heaney and Tabaranza conducted in 1994 and 1995, high on the steep slopes of one of the island's volcanoes.

Local people had not previously known of the mouse, though they have known of the parrot because of its value in the pet trade.

In 2002, Heaney, Tabaranza, and Eric Rickart, of the Utah Museum of Natural History, described a different species of forest-living rodent, Bullimus gamay, from Mt. Timpoong, the same mountain where the new mouse was collected. A frog (Oreophryne nana) named in 1967 had been thought to be the only vertebrate restricted to the island prior to the surveys by Heaney and Tabaranza.

"Very few states in the United States, and few countries in Europe, have four endemic species of vertebrates, making it clear why tiny Camiguin Island is deserving of international attention," Heaney said. "And it is almost certain that other organisms on Camiguin are also endemic; they just have not been studied yet."

The Field Museum - http://www.fieldmuseum.org

Mars (NASA)

New Scientist News Release by Maggie McKee

April 6, 2006 - A fifth terrestrial planet may once have orbited between Mars and Jupiter.

Although gravitational disturbances would have sent the planet hurtling into the sun or out into space long ago, traces of this long-gone world may still be visible in part of the asteroid belt today.

Recent simulations have suggested that the gas giants of our solar system formed with circular orbits but moved into their more elongated paths about 4 billion years ago – 700 million years after the solar system formed.

While the gas giants were in circular orbits, rocky planets should have formed in stable orbits out to a distance of 2.2 astronomical units (1 AU = 1 Earth- Sun distance).

However, there are no planets between Mars, which lies at 1.5 AU from the sun, and Jupiter at 5.2 AU.

That puzzled Sean Raymond of the University of Colorado in Boulder and John Chambers of the Carnegie Institution in Washington DC.

"There's room for another planet between Mars and Jupiter," says Chambers. "Given that planets formed everywhere else, why couldn't another planet have formed there?"

Jupiter (NASA)

The researchers modelled what would have happened in that region, and found that a planet about the size of Mars could have formed 2 AU from the sun and remained stable there until the orbits of the gas giant changed.

Their simulations show that the migration of Jupiter and Saturn greatly disturbed the orbits of other planets, and this could have kicked the fifth rocky planet out of its orbit – either into the sun or out of the solar system altogether. If the planet was swallowed by the sun, it was probably too small to leave any measurable trace in the sun's composition. "But it's possible the orbits of the asteroids today show some memory of having had a planet in the asteroid belt," says Chambers.

Raymond believes this evidence lies in a family of asteroids called Hungaria, which are clustered at 1.9 AU. These bodies orbit in a plane tilted by about 25 degrees to the main disc of the solar system, which suggests they may have been swept off course in wake of the lost planet as it ploughed through the asteroid belt, says Raymond. "They're in this tiny little area that's just barely stable – I don't know how else they would have gotten there."

If it can be confirmed that the planet once existed, it would imply that planetary systems are dynamic environments, says Chambers.

The researchers presented their results at the Astrobiology Science Conference in Washington DC last week.

This article appears in New Scientist Magazine Issue: 8 April 2006

New Scientist - http://www.newscientist.com

This image shows the central region of the galaxy cluster Abell 400. The colour coding gives the temperature of the X-ray emitting gas trapped in the cluster: black-cold (18 million degrees Celsius) to white- hot (38 million degrees Celsius). The contours show the radio emission from the jets of plasma being expelled by the black holes. As the two black holes stream through the gas at supersonic velocities, the jets are bent toward the top of the image. The gas in front of the black holes is compressed and heated, as seen by the hotspot below them. The inset shows a blow up of the central regions. Each dot represents a position where an X-ray photon has struck Chandra's X-ray camera. The two black holes are seen as bright regions where as many as 250 X-ray photons struck the camera. The contours again show the radio emission from the black holes and the jets of plasma being ejected from them. (EDP Sciences)

Journal Astronomy & Astrophysics News Release

April 6, 2006 - An international team of astronomers led by D. Hudson from the University of Bonn has detected a proto supermassive binary black hole in images of NASA's Chandra X-ray observatory.

They found that these two black holes are gravitationally bound and orbit each other. Their results will be published in an upcoming issue of Astronomy & Astrophysics.

An international team of astrophysicists, led by D. Hudson from the University of Bonn and including the U.S. Naval Research Laboratory and the University of Virginia, presents their X-ray detection of a proto supermassive binary black hole. Their results will be published in an upcoming issue of Astronomy & Astrophysics.

The image of this proto binary black hole was obtained with NASA's Chandra X-ray Observatory. The two black holes have already been seen in radio images. The new X-ray images provide unique evidence that these two black holes are in the process of forming a binary system; that is, they are gravitationally bound and orbit each other.

The two black holes are located in the nearby galaxy cluster Abell 400. With high-resolution Chandra data, the team was able to spatially resolve the two supermassive black holes (separated by 15") at the centre of the cluster. Each black hole is located at the centre of its respective host galaxy and the host galaxies appear to be merging.

It is not, however, just the two host galaxies that are colliding - the whole cluster in which they live is merging into another neighbouring galaxy cluster.

Using these new data, the team show that the two black holes are moving through the intracluster medium at the supersonic speed of about 1200 km/s. The wind from such a motion would cause the radio plasma emitted from these two black holes to bend backwards. Although this bending had been observed previously, the cause of it was still being debated.

LISA will observe gravitational waves from several sources. One is the coalescences of massive black holes that result from the merging of galaxies. (NASA)

Since the bending of the jets due to this motion is in the same direction, it suggests that the two black holes are travelling along the same path within the cluster and are therefore gravitationally bound.

These two black holes became gravitationally bound when their host galaxies collided. In several million years, the two black holes will probably coalesce causing a burst of gravitational waves, as predicted by Einstein's theory of relativity.

This event will produce one of the brightest sources of gravitational radiation in the Universe. Although we will not be around to see this particular one, the observations provide additional evidence that such bound systems exist and are currently merging.

The gravitational waves produced by these mergers are believed to be the biggest source of gravitational waves to be detected by the future Laser Interferometer Space Antenna (LISA).

"X-ray detection of the proto supermassive binary black hole at the centre of Abell 400" by D.S Hudson, T.H. Reiprich, T.E. Clarke, and C.L. Sarazin. To be published in Astronomy & Astrophysics. Full article available in PDF format - http://www.edpsciences.org/articles/aa/pdf/press-releases/PRAA200608.pdf

Laser Interferometer Space Antenna - http://lisa.nasa.gov

Journal Astronomy & Astrophysics - http://www.edpsciences.org

RS Oph is situated in the "Snake Charmer" constellation.

Arizona State University News Release

TEMPE ARIZONA April 6, 2006 – An international team of astronomers today is reporting on a discovery of a star exploding inside another star. The discovery is helping astronomers learn more about the structure of a red giant star, how shock waves move through a star and revealing how one type of binary star system goes through the end stages of its life, the astronomers report.

Speaking at the National Astronomy Meeting in Leicester, U.K., the international team of 14 astronomers described what they saw as they monitored the explosion of RS Ophiuchi, a recurrent nova that lights up in the sky roughly every 20 years. RS Oph, as it is called, normally a very dim object in the sky was found to be visible to the unaided eye on Feb. 12, 2006 by Japanese amateur astronomers.

It was the fifth time in the last 108 years RS Oph exploded, and the first time it was viewed in unprecedented detail by an armada of space- and ground-based telescopes, said Sumner Starrfield, an ASU Regents professor of astronomy and a member of the international team monitoring the star system. Starrfield leads the U.S. portion of the effort. Among the telescopes and detectors trained on RS Oph were x-ray telescopes, an infrared telescope and a radio telescope.

In addition to Starrfield, the team monitoring RS Oph includes Michael Bode of Liverpool John Moores University, U.K.; Tim O'Brien, Jodrell Bank Observatory, University of Manchester, U.K.; Julian Osborne and Kim Page, University of Leicester, U.K.; Stewart Eyres, University of Central Lancaster, U.K.; and Nye Evans, University of Keele, U.K.

A Red Giant Star (NASA)

While RS Oph is a well-known and well-documented star system the fact that the astronomers were able to train their instruments and telescopes on the object early in the explosion process is shedding new light on it, Starrfield said.

"We were floored to see how bright this star was in x rays when we first observed it, and then it changed every day we pointed at it with our telescopes," Starrfield said. "We estimate the gas exploded off the white dwarf to be about 100 million degrees, about six times hotter than the gas at the center of our Sun. We are seeing about an Earth mass of material expand at more than 10 million kilometers/hour. The expanding gas from the explosion is now larger in size than our own solar system."

RS Oph is more than 5,000 light years away from Earth in the constellation Ophiuchi. A binary star system, it consists of a white dwarf star (the super-dense core of a star, about the size of the Earth, that has reached the end of its main hydrogen-burning phase of evolution and has shed its outer layers) in close orbit with a much larger red giant star (which is one step behind it in terms of its life-cycle).

The two stars are so close together that hydrogen-rich gas from the outer layers of the red giant is continuously pulled onto the dwarf by its high gravity. After about 20 years of this, enough gas has been accreted that a runaway thermonuclear explosion occurs on the white dwarf's surface. The luminous energy increases in less than a day to more than 100,000 times that of the Sun, and the accreted gas (several times the mass of the Earth) is ejected into space.

"This explosion is similar to that of a terrestrial hydrogen bomb," says Starrfield. "RS Oph can be thought of as one of the largest and most powerful hydrogen bombs in the universe."

To get explosions like this five times a century means that the white dwarf must be near a maximum mass without collapsing to become an even denser neutron star or black hole. What is also unusual in RS Oph is that because the red giant is losing enormous amounts of gas in a wind that envelops the whole system, the explosion on the white dwarf occurs 'inside' its companion's extended atmosphere and the very high speed ejected gas then slams into it.

Eta Carinae, an impressive double-lobed supernova remnant. (NASA)

"We are learning about the chemical composition of the red giant and how fast it is losing matter itself," Starrfield explained. "With this information we can predict how much longer the red giant will live before becoming a white dwarf."

If the red giant lives long enough, then the white dwarf could explode as a white dwarf supernova, which is the "type of supernova that astronomers use to study the evolution and fate of the universe itself," Starrfield said.

"Studies of RS Oph can shed light on these tremendous explosions that can be seen across the universe."

O'Brien, of Jodrell Bank Observatory, said that by looking at this explosion with advanced technology telescopes, the astronomers are recording in unprecedented detail the entire explosion process.

"Both radio and x-ray observations from the last outburst gave us tantalizing glimpses of what was happening as the outburst evolved," O'Brien said.

"This time we have developed much more advanced computer models and more sensitive telescopes. We have also opened the x-ray part of the spectrum to highly detailed studies. The combination of the two (instruments and models) will undoubtedly lead to a greater understanding of the circumstances and consequences of the explosion."

Michael Bode, leader of the UK team and the person who presented at the National Astronomy Meeting, added that RS Oph is a rare combination of a known star system with a predictable pattern of exploding every 20 years.

"We have a unique opportunity [through the study of RS Oph] to better understand such things as run away thermonuclear explosions and the end points of the evolution of stars," Bode said.

Arizona State University - http://www.asu.edu

The Impact moment on the Don Quijote mission: The Orbiter spacecraft (Sancho) has retreated to a safe distance to observe how the Impactor spacecraft (Hidalgo) crashes into the asteroid. After the Impact Sancho will come closer and inspect the changes. (ESA - AOES Medialab)

European Space Agency News Release

April 3, 2006 - If a large asteroid such as the recently identified 2004 VD17 – about 500 m in diameter with a mass of nearly 1000 million tonnes - collides with the Earth it could spell disaster for much of our planet. As part of ESA’s Near-Earth Object deflecting mission Don Quijote, three teams of European industries are now carrying out studies on how to prevent this.

ESA has been addressing the problem of how to prevent large Near-Earth Objects (NEOs) from colliding with the Earth for some time. In 1996 the Council of Europe called for the Agency to take action as part of a “long-term global strategy for remedies against possible impacts”. Recommendations from other international organisations, including the UN and the Organisation for Economic Cooperation and Development (OECD), soon followed.

In response to these and other calls, ESA commissioned a number of threat evaluation and mission studies through its General Studies Programme (GSP). In July 2004 the preliminary phase was completed when a panel of experts appointed by ESA recommended giving the Don Quijote asteroid-deflecting mission concept maximum priority for implementation.

Now it is time for industry to put forward their best design solutions for the mission.

Following an invitation to tender and the subsequent evaluation process, three industrial teams have been awarded a contract to carry out the mission phase-A studies.

· a team with Alcatel Alenia Space as prime contractor includes subcontractors and consultants from across Europe and Canada; Alcatel Alenia Space developed the Huygens Titan probe and is currently working on the ExoMars mission

· a consortium led by EADS Astrium, which includes Deimos Space from Spain and consultants from several European countries, brings their experience of working on the design of many successful ESA interplanetary missions such as Rosetta, Mars and Venus Express.

The key moment of the Don Quijote mission: the Impactor spacecraft (Hidalgo) smashes into the asteroid while observed, from a safe distance, by the Orbiter spacecraft (Sancho). (ESA - Medialab)

· a team led by QinetiQ (UK), which includes companies and partners in Sweden and Belgium, draws on their expertise in mini and micro satellites including ESA’s SMART-1 and Proba projects.

This month the three teams began work and a critical milestone will take place in October when the studies will be reviewed by ESA with the support of an international panel of experts. The results of this phase will be available next year.

No reason for panic – yet

The risk is still small however, and may decrease even further when new observations are carried out. Still, if this or any other similar-sized object, such as 99942 Apophis, an asteroid that will come close enough to the Earth in 2029 to be visible to the naked eye, collided with our planet the energy released could be equivalent to a significant fraction of the world's nuclear arsenal, resulting in devastation across national borders.

Luckily, impacts with very large asteroids are uncommon, although impacts with smaller asteroids are less unlikely and remote in time. In 1908 an asteroid that exploded over Siberia devastated an unpopulated forest area of more than 2000 km²; had it arrived just a few hours later, Saint Petersburg or London could have been hit instead.

Fossils of the Solar System

Asteroids are a part of our planet’s history. As anyone visiting the Barringer Meteor Crater in Arizona, USA or aiming a small telescope at the Moon can tell, there is plenty of evidence that the Earth and its cosmic neighbourhood passed through a period of heavy asteroid bombardment.

An image of Comet 67P/Churyumov-Gerasimenko. (ESA and ESO)

On the Earth alone the remains of more than 160 impacts have been identified, some as notorious as the Chicxulub crater located in Mexico’s Yucatan peninsula, believed to be a trace of the asteroid that caused the extinction of the dinosaurs 65 million years ago.

Collisions have shaped the history of our Solar System. Because asteroids and comets are remnants of the turbulent period in which the planets were formed, they are in fact similar to ‘time capsules’ and carry a pristine record of those early days.

By studying these objects it is possible to learn more about the evolution of our Solar System as well as ‘hints’ about the origins of life on Earth.

Comet 67P/Churyumov-Gerasimenko is one of these primitive building blocks and will be visited by ESA’s Rosetta spacecraft in 2014, as a part of a very ambitious mission - the first ever to land on a comet. Rosetta will also visit two main belt asteroids (Steins and Lutetia) on its way to comet 67P/Churyumov-Gerasimenko. The mission will help us to understand if life on Earth began with the help of materials such as water and organisms brought to our planet by 'comet seeding'.

The moments before impact... The Impactor spacecraft (Hidalgo) heads towards the target asteroid. (ESA - AOES Medialab)

ESA’s Science programme is already looking at future challenges, and its Cosmic Vision 2015-2025 plan has identified an asteroid surface sample return as one of the key developments needed to further our understanding of the history and composition of our Solar System.

Work still in progress

Asteroids and comets are fascinating objects that can give or take life on a planetary scale. Experts around the world are putting all their energy and enthusiasm into deciphering the mysteries they carry within them.

With an early launch provisionally scheduled for 2011, Don Quijote will serve as a ‘technological scout’ not only to mitigate the chance of the Earth being hit by a large NEO but also for the ambitious journeys to explore our solar system that ESA will continue to embark upon. The studies now being carried out by European industry will bring the Don Quijote test mission one step nearer.

Don Quijote is a NEO deflection test mission based entirely on conventional spacecraft technologies. It would comprise two spacecraft - one of them (Hidalgo) impacting an asteroid at a very high relative speed while a second one (Sancho) would arrive earlier at the same asteroid and remain in its vicinity before and after the impact to measure the variation on the asteroid’s orbital parameters, as well as to study the object. Secondary mission goals have also been defined, which would involve the deployment of an autonomous surface package and several other experiments and measurements.

European Space Agency - http://www.esa.int