For the first time, astronomers have used the same imaging technology found in digital cameras to take a photo of a planet outside our Solar System with a ground-based telescope.
Credit: Jared Males/UA
University of Arizona researchers have taken images of a planet outside our Solar System with an Earth-based telescope using essentially the same type of imaging sensor found in digital cameras, instead of an infrared detector. Although it still has a long way to go, this new method brings astronomers a step closer to obtaining direct images of Earth-like planets from the visible part of the light spectrum.
"This is an important next step in the search for exoplanets, because imaging in visible light instead of infrared is what we likely have to do if we want to detect planets that might be suitable for harbouring life," said Jared Males, lead author on a report to be published in The Astrophysical Journal.
Even though the image was taken at a wavelength just beyond human eye visibility, the use of a digital camera-type imaging sensor – known as a charge-coupled device (CCD) – opens up the possibility of imaging exoplanets in visible light, which has not been possible with Earth-based telescopes until now. So far, all Earth-based images taken of exoplanets close to their stars have been infrared images, which detect the planets' heat. This limits the technology to gas giants – massive, hot planets, still young enough to shed heat. In contrast, older and possibly habitable planets that have cooled since their formation don't show up in infrared images as readily, and to image them, astronomers will have to rely on cameras capable of detecting visible light.
"Our ultimate goal is to image what we call pale blue dots," said Laird Close, a professor in the Department of Astronomy, who co-authored the paper. "After all, the Earth is blue. And that's where you want to look for other planets: in reflected blue light."
Pale blue dot: Earth-like planets like this imaginary world may one day be photographed in visible light.
The photographed planet, Beta Pictoris b, is located approximately 63 light-years away in the constellation of Pictor, orbiting the 4th magnitude debris disk star Beta Pictoris. It orbits the star at only nine times the Earth-Sun distance, making its orbit smaller than Saturn's. In the team's CCD images, Beta Pictoris b appears about 100,000 times fainter than its host star, making it the faintest object imaged so far at such high contrast and at such relative proximity to its star. New images of this planet helped to confirm that its atmosphere is at a temperature of roughly 2600 degrees Fahrenheit (1700 Kelvin). It is estimated that Beta Pictoris b has a radius about 65% larger than Jupiter's.
"Because the Beta Pictoris system is 63.4 light years from Earth, the scenario is equivalent to imaging a dime right next to a lighthouse beam from more than four miles away," Males said. "Our image has the highest contrast ever achieved on an exoplanet that is so close to its star."
As well as the host star's overwhelming brightness, the astronomers had to overcome turbulence in Earth's atmosphere, which causes stars to twinkle and images to blur. The success reported here is mostly due to an adaptive optics system developed by Close and his team that eliminates much of the atmosphere's effect.
The Magellan Adaptive Optics technology is very good at removing this turbulence, or blurring, by means of a deformable mirror changing shape 1,000 times each second in real time. Adaptive optics have been used for more than 20 years at observatories in Arizona – most recently at the Large Binocular Telescope – and the latest version has now been deployed in the high desert of Chile at the Magellan 6.5-metre telescope.
The team also imaged the planet with both of MagAO's cameras, giving the scientists two completely independent simultaneous images of the same object in infrared, as well as bluer light, to compare and contrast.
"An important part of signal processing is proving that the tiny dot of light is really a planet and not a speckle of noise," said Katie Morzinski, a member of the MagAO team. "I obtained the second image in the infrared spectrum – at which the hot planet shines brightly – to serve as an unequivocal control that we are indeed looking at the planet. Taking the two images simultaneously helps to prove the planet image on the CCD is real and not just noise."
NASA has announced the discovery of 715 exoplanets by its Kepler mission, increasing the total number of confirmed planets outside our Solar System to nearly 1,700.
The newly-verified worlds orbit 305 stars, revealing multiple-planet systems much like our own Solar System. Nearly 95% of these planets are smaller than Neptune, which is almost four times the size of Earth. This discovery marks a significant increase in the number of known small-sized planets more akin to Earth than previously identified exoplanets.
"The Kepler team continues to amaze and excite us with their planet hunting results," said John Grunsfeld, associate administrator for NASA's Science Mission Directorate in Washington. "The fact that these new planets and solar systems look somewhat like our own, portends a great future when we have the James Webb Space Telescope in space to characterise the new worlds."
Since the discovery of the first planets outside our solar system in the mid-late 1990s, verification has been a laborious planet-by-planet process. Now, scientists have a statistical technique that can be applied to many planets at once when they are found in systems that harbour more than one planet around the same star.
"Four years ago, Kepler began a string of announcements of first hundreds, then thousands, of planet candidates – but they were only candidate worlds," said Jack Lissauer, a planetary scientist at NASA's Ames Research Centre. "We've now developed a process to verify multiple planet candidates in bulk, to deliver planets wholesale, and have used it to unveil a veritable bonanza of new worlds."
Four of these new planets are less than 2.5 times the size of Earth and orbit in their sun's habitable zone, defined as the range of distance from a star where the surface temperature may be suitable for life-giving liquid water. One of these habitable zone planets, Kepler-296f, orbits a star roughly half the size and 5% the brightness of our sun. Kepler-296f is twice the size of Earth – but scientists do not yet know whether it is a gas world, with a thick hydrogen-helium envelope, or a water world surrounded by a deep ocean.
This latest find brings the confirmed count of planets outside our solar system to nearly 1,700. As we continue to reach toward the stars, each discovery brings us one step closer to a more accurate understanding of our place in the Galaxy. Launched in 2009, Kepler is the first NASA mission to find potentially habitable Earth-size planets. So far, it has discovered more than 3,600 planet candidates, of which 961 have been verified as bona-fide worlds. Details of the 750 planets announced this week are published in The Astrophysical Journal on 10th March.
The first global, detailed geologic map of Ganymede – the largest moon in our Solar System – has been produced by researchers in the U.S.
Using images from NASA's Voyager flyby (1979) and the orbital Galileo probe (1995-2003), researchers have created the first global geological map of Jupiter's largest moon, Ganymede. With its varied terrain and possible underground ocean, Ganymede is considered a prime target in the search for habitable environments in our Solar System, and the researchers hope this new map will aid in future exploration.
The work – led by Professor Geoffrey Collins of Wheaton College in Massachusetts – took years to complete. It was published this week by the U.S. Geological Survey and is available as a PDF download along with a geospatial database.
"This map illustrates the incredible variety of geological features on Ganymede and helps to make order from the apparent chaos of its complex surface," said Robert Pappalardo of NASA's Jet Propulsion Laboratory in California. "It is helping planetary scientists to decipher the evolution of this icy world and will aid in upcoming spacecraft observations."
Jupiter Icy Moons Explorer (JUICE) is scheduled to reach the gas giant in 2030. This hi-tech orbiter will study Ganymede in extreme detail, identifying possible locations for a surface landing. Rovers might then follow later in the 2030s. NASA is contributing a U.S.-led instrument and hardware for two European-led instruments on JUICE.
Size comparison of Earth, the Moon, and Ganymede.
Since its discovery in 1610, Ganymede has been the focus of repeated observation – first by ground-based telescopes, then later flyby missions and spacecraft orbiting Jupiter. These studies depict a complex, icy world, whose surface is characterised by a striking contrast between its two major terrain types: the dark, very old, highly cratered regions, and the lighter, relatively younger regions marked with an extensive array of grooves and ridges.
According to researchers, three major geologic periods have been identified for Ganymede that involve the dominance of impact cratering, then tectonic upheaval, followed by a decline in geologic activity. This map illustrates surface features, such as furrows, grooves and impact craters, allowing scientists to decipher distinct geologic time periods for an object in the outer Solar System for the first time. It will enable researchers to compare the geology of other gas giant moons, because almost any type of feature that is found on other icy satellites has a similar feature somewhere on Ganymede.
"The surface of Ganymede is more than half as large as all the land area on Earth, so there is a wide diversity of locations to choose from," Collins said. "Ganymede also shows features that are ancient alongside more recently formed features, adding historical diversity in addition to geographic diversity."
Human colonisation of Ganymede is a possibility in the future – but will face major technical challenges. Although it possesses a magnetosphere (the only known moon with such a feature), it is overshadowed by Jupiter's magnetic field. Ganymede receives about 8 rem of radiation per day. It is more likely that Callisto (0.01 rem a day) would be settled first.
With new satellite technology, it is becoming possible to count individual whales and to automatically estimate their population size. Using Very High Resolution (VHR) satellite imagery, alongside image processing software, researchers were able to detect and count the number of whales breeding off the coast of Argentina.
Satellite images compared with aerial photograph (top right)
The new method, published this week in the journal PLoS ONE, could revolutionise how whale populations are estimated. Marine mammals are extremely difficult to count on a large scale and traditional methods – such as counting from platforms or land – can be costly and inefficient.
Lead author Peter Fretwell from the British Antarctic Survey (BAS): “This is a proof of concept study that proves whales can be identified and counted by satellite. Whale populations have always been difficult to assess; traditional means of counting them are localized, expensive and lack accuracy. The ability to count whales automatically, over large areas in a cost effective way will be of great benefit to conservation efforts for this and potentially other whale species.”
Previously, satellites have provided limited success in counting whales – but their accuracy has improved in recent years. The BAS team began by taking a single WorldView2 satellite image of a bay where southern right whales gather to calve and mate. Driven to near extinction, these whales have made a limited recovery following a whaling ban. In recent years, however, many deaths have been seen on their nursery grounds at Peninsula Valdes. Their population size is now unknown but with this sharp increase in calf mortality, estimates are needed.
The enclosed bays in this region contain shallow, calm waters – increasing the chance of spotting the whales from space. Three main criteria were used to identify whales: objects visible in the image should be the right size and shape; they should be in the right place (where whales would be expected to be) and there should be no (or few) other types of objects that could be mistaken as whales.
Whales in the image were manually counted, finding 55 probable whales, 23 possible whales and 13 sub-surface features. Several automated methods where then tested against these numbers. A ‘thresholding’ of the Coastal Band of the WorldView2 image gave the greatest accuracy. This part of the image uses light from the far blue end of the spectrum, which penetrates the water column deeper and reveals more whales. This technique found 89% of probable whales identified in the manual count.
This semi-automated technique needs some user input to identify the best threshold. Future satellite platforms, however, will provide much higher quality imagery and Worldview3 is planned to be launched later this year. This will allow for greater confidence in identifying whales and differentiating mother and calf pairs. Such technological advancements may also allow scientists to apply this method to other species.
NASA plans to send humans to Mars by 2033, but SpaceX CEO and billionaire entrepreneur Elon Musk wants to go there much sooner. In this interview, he outlines his thoughts on the current state of manned space exploration and his hopes for the not-too-distant future, including a "Mars Colonial Transporter".
Would you want to live on Mars? Let us know in the comments below...
Scientists using the far-infrared abilities of the Herschel space observatory have made the first definitive detection of water vapour on the largest and roundest object in the asteroid belt, Ceres. A space probe is due to arrive there in 2015.
Plumes of water vapour are thought to shoot up periodically from Ceres when portions of its icy surface warm slightly. Ceres is classified as a dwarf planet – a Solar System body larger than an asteroid, but smaller than a planet.
Herschel is a European Space Agency (ESA) mission with important NASA contributions.
"This is the first time water vapour has been unequivocally detected on Ceres or any other object in the asteroid belt and provides proof that Ceres has an icy surface and an atmosphere," said Michael Küppers of ESA in Spain, lead author of a paper in the journal Nature.
The results come at just the right time for NASA's Dawn mission, which is on its way to Ceres now after spending more than a year orbiting the large asteroid Vesta. Dawn is scheduled to arrive at Ceres in the spring of 2015, where it will take the closest ever look at its surface.
"We've got a spacecraft on the way to Ceres, so we don't have to wait long before getting more context on this intriguing result, right from the source itself," said Carol Raymond, deputy principal investigator at NASA's Jet Propulsion Laboratory in California. "Dawn will map the geology and chemistry of the surface in high resolution, revealing the processes that drive the outgassing activity."
For the last century, Ceres was known as the largest asteroid in our Solar System. But in 2006, the International Astronomical Union, a governing organisation responsible for naming planetary objects, reclassified Ceres as a dwarf planet because of its large size. It is roughly 590 miles (950 kilometres) in diameter. When it first was spotted in 1801, astronomers thought it was a planet orbiting between Mars and Jupiter. Later, other bodies with similar orbits were found, marking the discovery of our Solar System's main belt of asteroids.
Scientists believe Ceres contains rock in its interior with a thick mantle of ice that – if melted – would amount to more fresh water than is present on all of Earth. The materials making up Ceres likely date from the first few million years of our Solar System's existence and accumulated before the planets formed.
Scale image of Earth, the Moon and Ceres.
Until now, ice had been theorised to exist on Ceres but had not been detected conclusively. It took Herschel's far-infrared vision to see, finally, a clear spectral signature of the water vapour. But Herschel did not see water vapour every time it looked. While the telescope spied water vapour four different times, on one occasion there was no signature.
Here is what scientists think is happening: when Ceres swings through the part of its orbit that is closer to the Sun, a portion of its icy surface becomes warm enough to cause water vapour to escape in plumes at a rate of about 6 kilograms (13 pounds) per second. When Ceres is in the colder part of its orbit, no water escapes.
The strength of the signal also varied over hours, weeks and months, because of the water vapour plumes rotating in and out of Herschel's views as the object spun on its axis. This enabled the scientists to localise the source of water to two darker spots on the surface of Ceres, previously seen by NASA's Hubble Space Telescope and ground-based telescopes. These dark spots might be more likely to outgas because dark material warms faster than light material. When the Dawn spacecraft arrives at Ceres, it will investigate these features.
The results are somewhat unexpected because comets, the icier cousins of asteroids, are known typically to sprout jets and plumes, while objects in the asteroid belt are not.
"The lines are becoming more and more blurred between comets and asteroids," said Seungwon Lee of JPL, who helped with the water vapour models along with Paul von Allmen, also of JPL. "We knew before about main belt asteroids that show comet-like activity, but this is the first detection of water vapour in an asteroid-like object."
This evening – at 18:17 GMT – the European Space Agency's Rosetta spacecraft awoke from hibernation mode in preparation for its encounter with a comet, 67P/Churyumov–Gerasimenko.
The probe was launched in March 2004 and performed several flybys – of Earth, Mars and two asteroids – before entering a low power state in June 2011, in order to conserve energy. It has now reawakened and successfully communicated with ESA teams back on Earth.
The spacecraft consists of two main elements: the orbiter, which features 12 instruments, and the "Philae" robotic lander with an additional nine instruments. The first images of 67P are expected in May, from 2 million km (1.25 million mi) away. Rendezvous with the comet occurs in August this year, with deployment of the lander in November. Because of the comet's extremely low gravity, a harpoon system will lock the probe and drag it towards the surface, with legs dampening its eventual impact. Additional drills are used to further secure the lander on the comet.
Once on the surface, Philae will conduct the most detailed study of a comet ever attempted. Measurements of the ice, nucleus and chemical compounds present could reveal new details about the Solar System's history; perhaps even the origin of life itself. Among its many instruments are a drill that will bore 23 cm below the surface. A camera will also take high-resolution images (2048 × 2048 pixels) of the descent and a panorama of the landing site.
Rosetta will be the first spacecraft to fly alongside a comet as it heads towards the inner Solar System and the first to examine at close range how a frozen comet is transformed by the Sun's warmth. The mission runs until December 2015.
President Barack Obama has signed a budget that provides NASA with $17.6 billion for this year – fully funding both the heavy-lift Space Launch System and Orion capsule that will eventually take humans to Mars.
The Space Launch System (left) and Orion capsule (right).
NASA's budget for 2014 was passed by Congress earlier this week and officially signed by the President on Friday. A total of $17.65 billion has been allocated to the space agency, which is slightly less than the $17.7 billion it had requested. However, some analysts had expected a figure as low as $16.1 billion, due to recent budget cuts and spending concerns arising from the sequester of 2013. For space enthusiasts, the final approved figure is therefore a welcome surprise.
Some highlights from the budget include:
• $1,918 million for the Space Launch System (SLS).
The SLS is a heavy launch vehicle intended to replace the Space Shuttle. It is designed to be upgraded over time with more powerful versions. Initially carrying payloads of 70 metric tons into orbit, the SLS will eventually be fitted with an upper "Earth Departure Stage" capable of lifting at least 130 metric tons. This will be 12 metric tons greater than the Apollo-era Saturn V, making it the largest and most powerful rocket ever built. It will take astronauts and hardware to asteroids, the Moon, Mars, and most of the Earth's Lagrangian points. A first unmanned test launch is planned for 2017, with NASA being allocated an extra $200 million to ensure this deadline is met. A manned flight around the Moon and possibly to an asteroid is expected to occur in 2021, with manned missions to Mars in the 2030s. The additional funding in this year's budget will "maintain critical forward momentum" on the program, according to legislators.
• $1,197 million for the Orion Multi-Purpose Crew Vehicle (MPCV).
Orion is a small capsule designed to transport up to six astronauts and cargo beyond Earth orbit. It will be integrated with and carried by the SLS rockets. A first unmanned test flight is scheduled for later this year, during which its altitude will reach higher than any spacecraft intended for human use since 1973. Manned flights will commence in the 2020s.
• $5,151 million for science.
This includes $80 million for planning and development of a Europa mission. The next Discovery-class mission will be announced by May 2014, with selection of the mission(s) in September 2015. Meanwhile, NASA's flagship project and Hubble successor – the James Webb Space Telescope – remains funded and on track for delivery in 2018. Among its primary objectives will be capturing images of reionization and "first light" from stars after the Big Bang.
The remaining budget will go towards operational maintenance, space technology, aeronautics, grants, education and other services provided by NASA. Despite this week's good news, however, the longer term picture is less clear for NASA. As shown in the graph below, its budget as a percentage of the federal budget has been gradually declining and is now a mere fraction of its peak in the 1960s. It will be interesting to see how the private sector can influence the agency's strategy in the coming decades.
Climate change has not been strongly influenced by variations in heat from the sun, according to researchers from the University of Edinburgh's School of GeoSciences.
These findings cast doubt on the view that lengthy periods of warm and cold weather in the past might have been caused by periodic fluctuations in solar activity.
Research examining the causes of climate change in the northern hemisphere over the past 1000 years has shown that until 1800, the main driver of periodic changes in climate was volcanic eruptions. These tend to reduce the amount of sunlight reaching the Earth – causing cool, drier weather. Since 1900, greenhouse gases have been the primary cause of climate change.
The findings show that periods of low sun activity should not be expected to have a large impact on global temperatures and are expected to improve scientists' ability to predict future climate.
Scientists at the University of Edinburgh carried out the study using records of past temperatures constructed with data from tree rings and other historical sources. They compared this data record with computer-based models of past climate, featuring both significant and minor changes in the sun.
Their model of weak changes in the sun gave the best correlation with temperature records, indicating that solar activity has had a minimal impact on temperature over the past millennium.
Dr Andrew Schurer, of the University of Edinburgh's School of GeoSciences, said: "Until now, the influence of the sun on past climate has been poorly understood. We hope that our new discoveries will help improve our understanding of how temperatures have changed over the past few centuries, and improve predictions for how they might develop in future."
The study, published in Nature GeoScience, was supported by the Natural Environment Research Council.
Astronomers at the University of Notre Dame have spotted what appears to be the first known "exomoon", located 1,800 light years away.
The first known moon outside of our Solar System may have been found, based on a study by Professor David Bennett and a team of international colleagues. This satellite (designated "MOA-2011-BLG-262"), with half the mass of Earth, orbits a much larger planet with four Jupiter masses. The duo appear to be rogue, free-floating objects – lacking a parent star and drifting aimlessly through interstellar space. They were possibly ejected from a binary-star system after getting too close to the stars and being flung out with an unstable trajectory.
Detection was made by an unusual method known as gravitational microlensing. This is particularly well-suited to objects that emit little or no light, and was used earlier this year to spot the first exoplanet around a brown dwarf. It works by using gravitational distortion effects to focus a background object as it passes behind another, from which the mass and other characteristics can be determined. Only a small percentage of the 1,000 exoplanets confirmed so far have used this technique; the vast majority are found by Doppler spectroscopy or transit photometry.
However, it is unconfirmed at this stage whether MOA-2011-BLG-262 is actually a moon. Another possible scenario has emerged from the initial data, suggesting the pair may in fact consist of a brown dwarf orbited by a Neptune-mass planet lying much further away than 1,800 light years.
If the first model is correct, the exomoon would have to be around 20 million km (12.5 million mi) from its planet in order to fit the data. This is similar to many of the gas giant satellites in our Solar System. For comparison, the gap between Earth and our own Moon is 385,000 km (240,000 miles) on average, about 50 times less.
Even if unconfirmed this time, many exomoons will likely be found within the next decade, the study concludes. It is available online at Cornell University Library.
The DARPA Robotics Challenge is a $2 million prize competition run by the Defense Advanced Research Projects Agency. Open since October 2012 and concluding in December 2014, it aims to develop robots that can do "complex tasks in dangerous, degraded, human-engineered environments."
Among the competing entries is "Valkyrie" – a humanoid machine being developed by NASA. This is a variant of the earlier "Robonaut" that was delivered to the International Space Station in February 2011. As seen in the video below, it now features legs and interchangeable arms with 44 axes of movement, alongside a wide array of cameras and sensors. Valkyrie will eventually walk around untethered, pick up and manipulate objects while navigating a variety of terrain and even have the ability to drive vehicles.
In the future, it is hoped that robots like Valkyrie will be used in missions to Mars. Nicolaus Radford, Principal Investigator and team leader of the NASA JSC Dextrous Robotics Lab: "NASA saw a considerable overlap between what the DRC was trying to accomplish and NASA's goals as an agency. We want to get to Mars. Likely, NASA will send robots ahead of the astronauts to the planet. These robots will start preparing the way for the human explorers, and when the humans arrive, the robots and the humans will work together."
• In a related story, Google yesterday acquired Boston Dynamics, which has multi-million dollar contracts with DARPA and is behind such robots as ATLAS, BigDog and PETMAN. This is just the latest in a whole series of robotics companies recently bought by Google.
Mars One has secured lead suppliers for its first mission to Mars. Slated for a 2018 launch, this will include a robotic lander and orbiting communications satellite.
As we've blogged previously, Mars One is a not-for-profit company based in the Netherlands, which aims to construct the first permanent human settlement on Mars. Led by Dutch entrepreneur Bas Lansdorp, the plan is for a supply mission to be launched in January 2018, arriving in the same year. This will carry 2,500 kg (5,500 lb) of spare parts, solar panels and other items down to the surface. It would be followed by a rover and trailer in 2020, capable of towing equipment from landing sites to the settlement location. Six cargo units – consisting of two living units, two life support systems and two supply units – would be sent in 2022, using a rover signal as a beacon.
The outpost would be operational by 2023 and the first human crew would be delivered in 2024. These four astronauts would be joined by additional groups after that, reaching a total of 20 people by 2033. Every step of the crew’s journey will be documented for a reality TV program that will broadcast 24/7/365.
To many of our readers, this probably sounds too good to be true. And indeed, we have omitted the Mars One program from our timeline, until it becomes clearer that the project is financially and technically viable. However, the company has been making progress. Earlier this year, they secured their first investment, which was followed by a tremendous show of public support through their astronaut selection program, and now a crowdfunding campaign is underway.
This week, Mars One contracted both Lockheed Martin and Surrey Satellite Technology Ltd. (SSTL) to develop mission concept studies. This will result in Lockheed Martin building the lander, while SSTL handles the communications satellite. This 2018 mission will be a demonstration that provides "proof of concept" for some of the technologies important for a permanent human settlement on Mars.
Bas Lansdorp, Mars One Co-founder and CEO stated: “We’re very excited to have contracted Lockheed Martin and SSTL for our first mission to Mars. Both are significant players in their field of expertise and have outstanding track records. These will be the first private spacecraft to Mars and their successful arrival and operation will be a historic accomplishment.”
The surface lander will be based on the 2007 NASA Phoenix mission spacecraft. Lockheed Martin has a distinct legacy of participating in nearly every NASA mission to Mars. For the successful Phoenix mission, the company designed, built, tested and operated the lander for NASA.
“Lockheed Martin is very excited to have been contracted by Mars One. This is an ambitious project and we’re already working on the mission concept study – starting with the proven design of Phoenix,” said Ed Sedivy, Civil Space chief engineer at Lockheed Martin. “Having managed the Phoenix spacecraft development, I can tell you, landing on Mars is challenging and a thrill and this is going to be a very exciting mission.”
The lander will have the ability to scoop up Martian soil with a robotic arm similar to the Phoenix mission. A water experiment will extract water from the Martian soil. A power experiment will demonstrate the deployment and operation of thin-film solar panels on the surface, and a camera on the lander will be used to make continuous video recordings.
The demonstration satellite will provide a high bandwidth communications system in a Mars synchronous orbit and will be used to relay data and a live video feed from the lander on the surface of Mars back to Earth. Sir Martin Sweeting, Executive Chairman of SSTL: “We believe the commercialisation of space exploration is vital, in order to bring down costs and schedules and fuel progress. This study gives an unprecedented opportunity to take our tried and tested approach and apply it to Mars One’s imaginative and exhilarating challenge of sending humans to Mars through private investment.”
Arno Wielders, Co-founder and CTO of Mars One, said: "With our 2018 missions, Mars One brings the settlement of Mars one step closer to reality. The demonstration of water production on Mars is crucial for manned missions. The live video feed from the surface camera will bring Mars closer to people on Earth. And with the STEM education challenges and university competitions planned on our lander, we will enthuse a whole new generation for Mars exploration, even before our first crew lands."
Mars One decided to launch the lander and communications satellite in 2018, two years later than their original schedule. This new schedule provides time for development of the two spacecraft and for student participation in STEM education and university challenges.
Mars One’s mission will not be financed by any government. Instead, means of funding the project include sponsorships and exclusive partnerships. Mars One is in discussion with several partners about participating in specific components of the mission. As mentioned, a crowdfunding campaign has also been launched that enables people to donate online. Among other things, contributors will be granted voting rights for mission decisions in the future.
“Landing the first humans on Mars should be everyone’s mission and not just the mission of one country or organisation” said Lansdorp. “Our 2018 mission will change the way people view space exploration as they will have the opportunity to participate. They will not only be spectators, but also participants. We think it is important to involve people from all over the world in what we’re doing, and crowdfunding and crowdsourcing activities are important means to do that.”
By using lightweight "membrane optics" instead of traditional glass, a new generation of space telescopes could be deployed that reach sizes of 20 metres (68 foot) or larger.
As the need for higher-resolution orbital imagery expands, glass mirrors are fast approaching the point where they will be too large, heavy and costly for even the largest of today's rockets to carry to orbit. DARPA's Membrane Optical Imager for Real-Time Exploitation (MOIRE) program seeks to address these challenges by developing technologies that would make orbital telescopes much lighter, more transportable and more cost-effective. Currently in its second and final phase, the program recently successfully demonstrated a ground-based prototype that incorporated several critical technologies, including new lightweight polymer membrane optics to replace glass mirrors.
Instead of reflecting light with mirrors or refracting it with lenses, MOIRE's membrane optics diffract light. Roughly the thickness of household plastic wrap, each membrane serves as a Fresnel lens — it is etched with circular concentric grooves like microscopically thin tree rings, decreasing from hundreds of microns at the centre, down to only 4 microns at the outside edge. The diffractive pattern focuses light on a sensor that the satellite translates into an image.
MOIRE technology houses the membranes in thin metal "petals" that would launch in a tightly-packed configuration roughly 20 feet in diameter. Upon reaching its destination orbit, a satellite would then unfold the petals to create the full-size, multi-lens optics. The envisioned diameter of 68 feet (about 20 metres) would be the largest telescope optics ever made — dwarfing the glass mirrors contained in the world's most famous telescopes. This behemoth would be even larger than the 16-metre ATLAST observatory planned for 2025.
Looking down from geostationary orbit, it is believed a satellite using MOIRE optics could see approximately 40 percent of the Earth’s surface at once. It could focus on a 10 km-by-10 km region at 1-metre resolution and provide real-time video of this entire area at one frame per second. In its ground-based tests, MOIRE has achieved a technological first for membrane optics by nearly doubling their efficiency, from 30 percent to 55 percent.
Lt. Col. Larry Gunn, DARPA program manager: "Membrane optics could enable us to fit much larger, higher-resolution telescopes in smaller and lighter packages. In that respect, we're 'breaking the glass ceiling' that traditional materials impose on optics design. We're hoping our research could also help greatly reduce overall costs and enable more timely deployment using smaller, less expensive launch vehicles."
The Hubble Space Telescope has found evidence of water in the atmospheres of five distant exoplanets orbiting stars beyond our Solar System.
Using the Hubble Space Telescope, two teams of scientists have detected faint signatures of water in the atmospheres of five distant exoplanets. Atmospheric water on exoplanets has been reported previously – but this new study is the first to conclusively measure the profiles and intensities of these signatures on multiple worlds.
The five planets – WASP-17b, HD209458b, WASP-12b, WASP-19b and XO-1b – orbit stars ranging in distance from 154 to 1,000 light years from Earth. The strengths of their water signatures varied. WASP-17b, a planet with an especially puffed-up atmosphere, and HD209458b had the strongest signals. The signatures for the other three planets, WASP-12b, WASP-19b and XO-1b, are also consistent with water.
"We're very confident that we see a water signature for multiple planets," said Avi Mandell, planetary scientist at NASA's Goddard Space Flight Center, and lead author of an Astrophysical Journal paper describing the findings. "This work really opens the door for comparing how much water is present in atmospheres on different kinds of exoplanets – for example, hotter versus cooler ones."
The studies were part of a census of exoplanet atmospheres led by Prof. L. Drake Deming at the University of Maryland. Hubble's Wide Field Camera 3 was used to determine light absorption through the planets' atmospheres. The observations were made in a range of infrared wavelengths where a water signature, if present, would appear. The teams compared shapes and intensity of the absorption profiles, and the consistency of signatures gave them confidence they saw water.
"To actually detect the atmosphere of an exoplanet is extraordinarily difficult. But we were able to pull out a very clear signal, and it is water," said Deming, whose team employed a new technique with longer exposure times, which increased the sensitivity of their measurements.
The water signals were all less pronounced than expected, and the scientists suspect this is because a layer of haze or dust blankets each of the five planets. This haze can reduce the intensity of all signals from the atmosphere in the same way fog can make colours in a photograph appear muted. At the same time, haze alters the profiles of water signals and other important molecules in a distinctive way.
The five planets are "hot Jupiters" – massive worlds that orbit close to their host stars. The researchers were initially surprised that all five appeared to be hazy. But Deming and Mandell noted that other researchers are finding evidence of haze around exoplanets.
"These studies, combined with other Hubble observations, are showing us that there are a surprisingly large number of systems for which the signal of water is either attenuated or completely absent," said Heather Knutson of the California Institute of Technology, a co-author on Deming's paper. "This suggests that cloudy or hazy atmospheres may in fact be rather common for hot Jupiters."
Hubble's high-performance Wide Field Camera 3 is one of only a few capable of analysing the atmospheres of exoplanets many trillions of miles away. These exceptionally challenging studies can be done only if the planets are spotted while they are passing in front of their stars. Researchers can identify the gases in a planet's atmosphere by determining which wavelengths of the star's light are transmitted and which are partially absorbed.
As detection methods improve, astronomers will be able to search the atmospheres of Earth-sized planets. Some of the missions being planned in the future include the CHEOPS satellite (2017), James Webb Telescope (2018), the European Extremely Large Telescope (2022) and the Advanced Technology Large-Aperture Space Telescope (2025-2035).
Planetary Resources, Inc. was co-founded in 2010 by Peter Diamandis and Eric C. Anderson. This new startup company hopes to address one of the paramount problems faced on Earth: resource scarcity. It will achieve this by developing a robotic asteroid mining industry, based on reduced fuel costs. As this video explains, prospecting and mining asteroids could drive economic growth into the Solar System, where potentially trillions of dollars' worth of metals and minerals lie. Planetary Resources has already signed an agreement with Virgin Galactic for payload services. In early 2014, they plan to launch "Arkyd-3", a testbed for the larger Arkyd-100 spacecraft that will hunt for asteroids.
As nations strive to put humans farther into space for longer periods of time, the real loser in this new space race could be the astronauts themselves. New experiments conducted on the International Space Station (ISS) involving cells that line the inner surfaces of blood vessels (endothelial cells) show that microgravity accelerates cardiovascular disease and the biological aging of cells. These findings are presented in the November 2013 issue of The FASEB Journal.
"Understanding the cellular and molecular events of senescence might help in finding preventive measures that are useful to improve the quality of life of millions of people," said Silvia Bradamante, a researcher from the CNR-ISTM, Institute of Molecular Science and Technologies in Milan, Italy. "Our study further supports the role of oxidative stress in accelerating aging and disease."
In this report, Bradamante and colleagues examined endothelial cells in real microgravity aboard the ISS and conducted deep gene expression and protein analysis on the cells. They compared space-flown endothelial cells to endothelial cells cultured under normal gravity — looking for differences in gene expression and/or in the profile of secreted proteins. Space-flown cells differentially expressed over 1,000 genes, and secreted high amounts of pro-inflammatory cytokines. Ultimately, this induced significant oxidative stress, causing inflammation among endothelial cells, which in turn, led to atherosclerosis and cell senescence (biological aging).
"As we plan to send people deeper into space than ever before, and for longer flights, we've got to make sure that they remain in the best health possible," said Gerald Weissmann, Editor-in-Chief of The FASEB Journal. "We've evolved to rely on gravity to regulate our biology, and without it, our tissues become confused. Worst of all: they age faster!"
NASA's Kepler space telescope, now crippled and its four-year mission at an end, nevertheless provided enough data to complete its mission objective: to determine how many of the 200 billion stars in our galaxy have potentially habitable planets. Based on a statistical analysis of all the Kepler observations, astronomers at UC Berkeley and University of Hawaii, Manoa, now estimate that 22 percent of stars like the Sun have planets about the size of Earth and a surface temperature conducive to life. That amounts to several tens of billions of potentially habitable worlds.
New Horizons was launched by NASA in January 2006 to study the dwarf planet Pluto and return the first ever close-range photos of the distant world. This week, it reached another milestone on its long voyage.
The probe is now within 5 AU of Pluto. An astronomical unit (AU) is the average distance between the Earth and Sun – about 93 million miles, or 149 million kilometres. So far, New Horizons has travelled over 2.7 billion miles (4.4 billion km), which means it has completed 85% of its journey.
Alan Stern, New Horizons principal investigator: "It's exciting to be closing in on the Pluto system. The encounter begins in January 2015 – just over 14 months from now. You can really feel the energy level rising on this mission!"
After passing by Pluto, New Horizons will continue into the Kuiper belt, a region similar to the asteroid belt, but far larger – 20 times as wide and possibly 200 times as massive – and filled with icy remnants from the Solar System's formation. Mission planners are now searching for one or more additional Kuiper belt objects (KBOs) of around 50–100 km (31–62 mi) in diameter, for flybys similar to the spacecraft's Plutonian encounter.
By 2038, the probe will be 100 AU from the Sun. If still functioning, it will explore the outer heliosphere on the edge of interstellar space. After that, it will head in the direction of the constellation Sagittarius.
Bahram Mobasher and Naveen Reddy, from the University of California, Riverside, are members of a team that has discovered the most distant galaxy ever found. The galaxy is seen as it was just 700 million years after the Big Bang – when the universe was only 5 percent of its current age of 13.8 billion years.
Image credit: V. Tilvi, S.L. Finkelstein, C. Papovich, NASA, ESA, A. Aloisi, The Hubble Heritage, HST, STScI, and AURA.
In collaboration with astronomers at the University of Texas at Austin, Texas A & M University, and the National Optical Astronomy Observatories, Mobasher and Reddy identified a very distant galaxy candidate using deep optical and infrared images taken by the Hubble Space Telescope. Follow-up observations of this galaxy by the Keck Telescope in Hawaii confirmed its distance.
In searching for distant galaxies, the team selected several candidates, based on their colours, from the approximately 100,000 galaxies identified in the Hubble Space Telescope images taken as a part of the CANDELS survey – the largest project ever performed by the Hubble Space Telescope, with a total allocated time of 900 hours. However, using colours to sort galaxies is tricky, because some nearby objects can masquerade as distant galaxies.
Therefore, to measure the distance to these galaxies in a definitive way, astronomers use spectroscopy – a way of determining how much the wavelength of a galaxy’s light has shifted into the red part of the spectrum, due to the expansion of the universe. This phenomenon is called “redshift.” Since the expansion velocity (redshift) and distances of galaxies are proportional, the redshift gives astronomers a measure of the distance to galaxies.
“What makes this galaxy unique, compared to other such discoveries, is the spectroscopic confirmation of its distance,” said Mobasher, a professor of physics and observational astronomy.
Because light travels at 186,000 miles per second, when we look at distant objects, we are seeing them as they appeared in the past. The more distant we push these observations, the farther into the past we can see.
“By observing a galaxy that far back in time, we can study the earliest formation of galaxies,” he said. “By comparing properties of galaxies at different distances, we can explore the evolution of galaxies throughout the age of the universe.”
The discovery was made possible by a new instrument, MOSFIRE, commissioned on the Keck Telescope. Not only is the instrument extremely sensitive, but it is designed to detect infrared light – a region of the spectrum to where the wavelength of light emitted from distant galaxies is shifted – and could target multiple objects at a time. It was the latter feature that allowed the researchers to observe 43 galaxy candidates in only two nights at Keck, obtaining higher quality observations than previous studies.
By performing spectroscopy on these objects, researchers are able to accurately gauge the distances of galaxies by measuring a feature from the ubiquitous element hydrogen called the Lyman alpha transition. It is detected in most galaxies that are seen from a time more than one billion years from the Big Bang, but as astronomers probe earlier in time, the hydrogen emission line, for some reason, becomes increasingly difficult to see.
Of the 43 galaxies observed with MOSFIRE, the research team detected this feature from only one galaxy, z8-GND-5296, shifted to a redshift of 7.5. The researchers suspect they may have zeroed in on the era when the universe made its transition from an opaque state, in which most of the hydrogen was neutral, to a translucent state when most of the hydrogen was ionised (called the Era of Re-ionisation).
“The difficulty of detecting the hydrogen emission line does not mean that the galaxies are absent,” said Reddy, an assistant professor of astronomy. “It could be that they are hidden from detection behind a wall of neutral hydrogen.”
The team’s observations showed that z8-GND-5296 is forming stars extremely rapidly – producing about 330 times the mass of our Sun each year. By comparison, the Milky Way forms only two to three new stars per year. The new distance record-holder lies in the same part of the sky as the previous record-holder (redshift 7.2), which also happens to have a very high rate of star-formation.
“So we’re learning something about the distant universe,” said Steven Finkelstein, University of Texas at Austin, who led the project. “There are way more regions of very high star formation than previously thought. There must be a decent number of them if we happen to find two in the same area of the sky.”
“With the construction and commissioning of larger ground-based telescopes – the Thirty Metre Telescope in Hawaii and Giant Magellan Telescope in Chile – and the 6.5 metre James Webb Space Telescope in space, by the end of this decade we should expect to find many more such galaxies at even larger distances, allowing us to witness the process of galaxy formation as it happens,” Mobasher said.
Ukrainian astronomers at the Crimean Astrophysical Observatory have identified a 410 m (1345 ft) asteroid with a small chance of hitting Earth on 26th August, 2032.
The asteroid has been named 2013 TV135. It was discovered on 12th October by astronomer Gennady Borisov using a custom 0.2 m (7.9 in) telescope. Based on early observations, this rock has a 1 in 14,000 chance of impacting Earth – though NASA expects these odds to be stretched further as more data becomes available, so it probably isn't worth including on our timeline.
However, if such an impact did occur, it could be devastating. Given the mass and velocity, its kinetic energy would be equivalent to over 2,400 megatons of TNT. This is about 50 times the energy of Russia's 50 Mt Tsar Bomba, the largest nuclear detonation in history.
While its chances of hitting us might be low, this discovery is an important reminder that we need to remain vigilant when it comes to these asteroids. The number of confirmed near-Earth objects recently passed the 10,000 mark and there are possibly 10 times that many still waiting to be found.
Two asteroids with significantly greater odds are 2007 VK184 – due for a close approach in 2048 – and 1950 DA which is approaching our vicinity in 2880. Earlier this year, a 20 metre rock impacted Chelyabinsk in Russia, injuring 1,200 people and causing an explosion bigger than Hiroshima. These objects present a genuine threat to our survival and we cannot afford to be complacent.
The "Grasshopper" is an experimental reusable rocket being tested by SpaceX, whose founder is the billionaire entrepreneur Elon Musk. If successfully developed, it could dramatically cut the cost of space travel, with launch vehicles being reused instead of discarded and burning up on reentry. A total of eight tests have been conducted so far, with progressively higher and more difficult manoeuvres. This week, the Grasshopper completed its highest leap to date, reaching an altitude of 2,441 feet (744 m) before returning to the launch pad.
Astronomers using data from NASA's Kepler and Spitzer space telescopes have created the first cloud map of a planet beyond our solar system – a sizzling, Jupiter-like world known as Kepler-7b.
The planet is marked by high clouds in the west and clear skies in the east. Previous studies from Spitzer have resulted in temperature maps, but this is the first look at cloud structures on a distant world.
"By observing this planet with Spitzer and Kepler for more than three years, we were able to produce a very low-resolution 'map' of this giant, gaseous planet," said Brice-Olivier Demory, of Massachusetts Institute of Technology in Cambridge. Demory is lead author of a paper accepted for publication in the Astrophysical Journal Letters. "We wouldn't expect to see oceans or continents on this type of world, but we detected a clear, reflective signature that we interpreted as clouds."
Kepler has found over 150 confirmed exoplanets in 76 star systems – along with a further 3,250 unconfirmed candidates – and Kepler-7b was one of the first. The telescope's problematic reaction wheels prevent it from hunting planets anymore, but astronomers continue to pore over almost four years' worth of collected data.
Kepler's visible-light observations of Kepler-7b's moon-like phases led to a rough map of the planet that showed a bright spot on its western hemisphere. But these data were not enough on their own to decipher whether the bright spot was coming from clouds or heat. The Spitzer Space Telescope played a crucial role in answering this question.
Left: Spitzer. Right: Kepler
Like Kepler, Spitzer can fix its gaze at a star system as a planet orbits around the star, gathering clues about the planet's atmosphere. Spitzer's ability to detect infrared light means it was able to measure Kepler-7b's temperature, estimating it to be between 1,500 and 1,800 degrees Fahrenheit (1,100 and 1,300 Kelvin). This is relatively cool for a planet that orbits so close to its star – within 0.06 astronomical units (one astronomical unit is the distance from Earth and the Sun) – and, according to astronomers, too cool to be the source of light Kepler observed. Instead, they determined, light from the planet's star is bouncing off cloud tops located on the west side of the planet.
"Kepler-7b reflects much more light than most giant planets we've found, which we attribute to clouds in the upper atmosphere," said Thomas Barclay, at NASA's Ames Research Center, California. "Unlike those on Earth, the cloud patterns on this planet do not seem to change much over time – it has a remarkably stable climate."
The findings are an early step toward using similar techniques to study the atmospheres of planets more like Earth in composition and size.
"With Spitzer and Kepler together, we have a multi-wavelength tool for getting a good look at planets that are trillions of miles away," said Paul Hertz, director of NASA's Astrophysics Division in Washington. "We're at a point now in exoplanet science where we are moving beyond just detecting exoplanets, and into the exciting science of understanding them."
Imagine the distance between the Sun and the star nearest to it – Alpha Centauri. That's about 4.2 light years. Now, imagine as many as 10,000 of our Suns crammed into that relatively small space.
The diagram above shows the density of a galaxy that was recently discovered by an international team of astronomers led by a Michigan State University faculty member.
"This galaxy is more massive than any ultra-compact dwarfs of comparable size," said Jay Strader, MSU assistant professor of physics and astronomy, "and is arguably the densest galaxy known in the local universe."
As detailed in a recent edition of Astrophysical Journal Letters, the ultra-compact dwarf galaxy was found in the Virgo cluster of galaxies, located 54 million light years from our own Milky Way. What makes this galaxy – known as M60-UCD1 – so remarkable is that approximately half of its mass is found within a radius of only 80 light years. This would make the density of stars around 15,000 times greater than found in Earth's neighbourhood in the Milky Way.
"Traveling from one star to another would be a lot easier in M60-UCD1 than it is in our galaxy," Strader said. "Since the stars are so much closer in this galaxy, it would take just a fraction of the time."
The discovery of ultra-compact galaxies is relatively new – only within the past 10 years or so. Until then, astronomers could see these "things" way off in the distance, but assumed they were either single stars or very distant galaxies.
Another intriguing aspect of this galaxy is the presence of a bright X-ray source in its centre. One explanation for this is a giant black hole, weighing in at some 10 million times the mass of our sun.
Astronomers are trying to determine whether M60-UCD1 and other ultra-compact dwarf galaxies are either born as really jam-packed star clusters, or if they are galaxies that gradually get smaller because of stars being ripped away from them. The possible massive black hole, combined with the high galaxy mass and Sun-like levels of elements found in the stars, favour the latter idea. A giant black hole at the centre of M60-UCD1 helps tip the scales against the scenario where this galaxy was once a star cluster, since such large black holes are not found in these types of objects.
The galaxy was discovered using NASA's Hubble Space Telescope. Follow-up observations were done with NASA's Chandra X-ray Observatory and ground-based optical telescopes, including the Keck 10-metre telescope in Hawaii.
"Twenty years ago, we couldn't have done this," Strader said. "We didn't have Hubble or Chandra. This is one of those projects where you bring together the full force of NASA's great observatories, plus ground-based resources."
NASA's Curiosity rover has revealed the Martian environment lacks methane. This is surprising to researchers, because previous data reported by U.S. and international scientists indicated positive detections.
The roving laboratory performed extensive tests to search for traces of Martian methane. Whether the Martian atmosphere contains traces of the gas has been a question of high interest for decades, because methane could be a potential sign of life, although it can also be produced without biology.
"This important result will help direct our efforts to examine the possibility of life on Mars," said Michael Meyer, NASA's lead scientist for Mars exploration. "It reduces the probability of current methane-producing Martian microbes, but this addresses only one type of microbial metabolism. As we know, there are many types of terrestrial microbes that don't generate methane."
Since October 2012, Curiosity has analysed samples of the Martian atmosphere for methane six times and detected none. Given the extreme sensitivity of the instrument used – the Tunable Laser Spectrometer – and not detecting the gas, scientists calculate the amount of methane in the Martian atmosphere today must be no more than 1.3 parts per billion, which is about one-sixth as much as some earlier estimates.
"It would have been exciting to find methane, but we have high confidence in our measurements, and the progress in expanding knowledge is what's really important," said Chris Webster of NASA's Jet Propulsion Laboratory. "We measured repeatedly from Martian spring to late summer, but with no detection of methane."
Webster is lead scientist for the Tunable Laser Spectrometer, which is part of Curiosity's Sample Analysis at Mars (SAM) laboratory. It can be tuned specifically for detection of trace methane. The laboratory can also concentrate any methane to increase the gas' ability to be detected. The rover team are using this method to check for methane at concentrations well below 1 part per billion.
Methane, the most abundant hydrocarbon in our Solar System, has one carbon atom bound to four hydrogen atoms in each molecule. Previous reports of localised methane concentrations up to 45 parts per billion, which sparked interest in the possibility of a biological source on Mars, were based on observations from Earth and from orbit around Mars. However, the measurements from Curiosity are not consistent with such concentrations, even if the methane had dispersed globally.
"There's no known way for methane to disappear quickly from the atmosphere," said co-author Sushil Atreya of the University of Michigan. "Methane is persistent. It would last for hundreds of years in the Martian atmosphere. Without a way to take it out of the atmosphere quicker, our measurements indicate there cannot be much methane being put into the atmosphere by any mechanism – whether biology, geology, or by ultraviolet degradation of organics delivered by the fall of meteorites or interplanetary dust particles."
The highest concentration of methane that could be present without being detected by Curiosity's measurements so far would amount to no more than 10 to 20 tons per year of methane entering the Martian atmosphere, Atreya estimated. That is about 50 million times less than the rate of methane entering Earth's atmosphere. Details of these findings were published in the Thursday edition of Science Express.
NASA has narrowed to four the number of potential landing sites for its next mission to Mars, a lander designed to study the planet's interior.
The stationary Interior Exploration Using Seismic Investigations, Geodesy and Heat Transport (InSight) lander is scheduled to launch in March 2016 and land on Mars six months later. It will touch down at one of four sites selected in August from a field of 22 candidates. All four semi-finalist spots lie near each other on an equatorial plain in an area of Mars called Elysium Planitia.
"We picked four sites that look safest," said geologist Matt Golombek of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California. "They have mostly smooth terrain, few rocks and very little slope."
Scientists will focus two cameras from NASA's Mars Reconnaissance Orbiter on the semi-finalists in the coming months to gain data they will use to select the best of the four sites well before InSight is launched.
The mission will investigate processes that formed and shaped Mars and will help scientists better understand the evolution of our inner solar system's rocky planets, including Earth. Unlike previous Mars landings, what is on the surface in the area matters little in the choice of a site, except for safety considerations.
"This mission's science goals are not related to any specific location on Mars because we're studying the planet as a whole, down to its core," said Bruce Banerdt, InSight principal investigator at JPL. "Mission safety and survival are what drive our criteria for a landing site."
Each semifinalist site is an ellipse measuring 81 miles (130 kilometres) from east to west and 17 miles (27 kilometres) from north to south. Engineers calculate the spacecraft will have a 99 percent chance of landing within that ellipse, if targeted for the centre.
Elysium is one of three areas on Mars that meet two basic engineering constraints for InSight. One requirement is being close enough to the equator for the lander's solar array to have adequate power at all times of the year. The elevation must also be low enough to have sufficient atmosphere above the site for a safe landing. The spacecraft will use the atmosphere for deceleration during descent.
All four semifinalist sites, as well as the rest of the 22 of the candidate sites studied, are in Elysium Planitia. The only other two areas of Mars meeting the requirements of being near the equator at low elevation – Isidis Planitia and Valles Marineris – are too rocky and windy. Valles Marineris also lacks any swath of flat ground large enough for a safe landing.
Elysium Planitia. Topography data from MOLA, place names from Gazetteer of Planetary Nomenclature. Credit: Areong
InSight also needs penetrable ground, so it can deploy a heat-flow probe that will hammer itself up to 5 yards into the surface to monitor heat coming from the planet's interior. This tool can penetrate through broken-up surface material or soil, but could be foiled by solid bedrock or large rocks.
"For this mission, we needed to look below the surface to evaluate candidate landing sites," Golombek said.
InSight's heat probe must penetrate the ground to the needed depth, so scientists studied Mars Reconnaissance Orbiter images of large rocks near Martian craters formed by asteroid impacts. Impacts excavate rocks from the subsurface, so by looking in the area surrounding craters, the scientists could tell if the subsurface would have probe-blocking rocks lurking beneath the soil surface. InSight will also deploy a seismometer on the surface and use its radio for measurements.