Radar image of asteroid 2005 YU55, acquired in April 2010. Credit: NASA/Cornell/Arecibo.
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On Tuesday, November 8, at 6:28 p.m. EST, an asteroid the size of an aircraft carrier will soar past our planet at a distance closer than the Moon… and NASA scientists will be watching!
2005 YU55, a 400-meter (1,300-foot) -wide C-type asteroid, was discovered in December 2005 by Robert McMillan of the Spacewatch Program at the University of Arizona, Tucson. It’s pretty much spherical in shape and dark – darker than charcoal, in fact! Scientists with NASA’s Near-Earth Objects Observation Program will begin tracking it on November 4 using the 70-meter radar telescope at the Deep Space Network in Goldstone, California , as well as with the Arecibo Planetary Radar Facility in Puerto Rico beginning November 8. They will continue tracking 2005 YU55 through November 10.
Animation of 2005 YU55's trajectory on Nov. 8. (NASA/JPL) Click to play.
YU55’s orbit is well understood by scientists. It has come this way before, and although this is the closest it’s come to Earth in at least two centuries it will still be at least 324,600 kilometers (201,700 miles) away at nearest approach. That’s about 85% of the distance to the Moon.
It will approach from the sunward side, making viewing in visible light difficult until after it’s made its closest pass.
Other than the excitement it will most likely cause amongst radar astronomers, 2005 YU55 will have no physical effect on our planet. (There have been some rumors circulating online about this particular asteroid’s upcoming pass, in regards to earthquakes and tidal fluctuations and atmospheric disturbances and other such nonsense… the bottom line is that, like the ill-fated comet Elenin, 2005 YU55 has never been known to pose any threat to Earth.)
“YU55 poses no threat of an Earth collision over, at the very least, the next 100 years,” said Don Yeomans, manager of NASA’s Near-Earth Object Program Office at JPL. “During its closest approach, its gravitational effect on the Earth will be so miniscule as to be immeasurable. It will not affect the tides or anything else.”
The 70m telescope at the Goldstone Deep Space Communications Complex in California's Mojave Desert. (NASA/JPL)
Scientists are very eager though to have a prime opportunity to study this quarter-mile-wide world as it makes its closest pass. The giant telescopes at Goldstone and Arecibo will bounce radar waves off the asteroid, mapping its size and shape, and hopefully obtain some very high-resolution images.
“Using the Goldstone radar operating with the software and hardware upgrades, the resulting images of YU55 could come in with resolution as fine as 4 meters per pixel. We’re talking about getting down to the kind of surface detail you dream of when you have a spacecraft fly by one of these targets.”
– Lance Benner, JPL radio astronomer
Even though YU55 will remain at a safe distance the event is still quite notable. The last time an object this large came so close to Earth was in 1976… and scientists weren’t even aware of it at the time. Luckily we now have programs like the Near-Earth Objects Observations Program – a.k.a. “Spaceguard” – to identify asteroids like this, hopefully in time to know if they could become a danger to our planet in either the near or distant future.
As of now, no large space rock with Earth’s name on it has been positively identified… but that doesn’t mean there’s nothing out there either. We need to keep diligent, keep looking and, above all, keep funding programs like this. If anything, this pass should serve as a reminder – however harmless – that we certainly are not alone in the solar system!
Based on an observation posted on the Near Earth Object confirmation page from an image taken by A. D. Grauer using the mount Lemmon observatory, Faulkes telescope team members Nick Howes, Giovanni Sostero and Ernesto Guido along with University of Glamorgan student Antos Kasprzyk and amateur astronomer Iain Melville, imaged what is potentially some of the first direct evidence for a Trojan Jupiter Comet
Comet P/2010 TO20 (LINEAR-GRAUER) was immediately recognised by the team from looking at the orbit to be a highly unusual object, but it was only when the images came through from the faulkes observations that the true nature of the object became clear
The observations showed a distinct cometary appearance, with a sharp central condensation, compact coma and a wide, fan-shaped tail.
This is no ordinary comet, and supports the theory and initial spectral observation work by a team using the keck telescope in Hawaii. Closer analysis of their object (part of a binary known as the Patroclus pair) showed that it was made of water ice and a thin layer of dust, but at the time of writing, no direct images of a Jupiter Trojan showing evidence of a coma and tail had been taken.
The Faulkes teams above image, combined with the original observations by Grauer clearly show a cometary object, thus confirming the Keck team’s hypothesis.
According to the CBET released today “After two nights of observations of Grauer’s comet had been received at the Minor Planet Center.
Spahr realized that this object was identical with an object discovered a year ago by the LINEAR project (discovery observation tabulated below; cf. MPS 351583) that appeared to be a Jupiter Trojan minor planet.”
The observations have now proved it is not a minor planet, but a comet.
This discovery could provide new clues about the evolution of the Solar System, suggesting that the Gas Giants formed closer to the Sun and as they moved further away, they caused massive perturbations with Kuiper Belt objects, trapping some in their own orbits.
Nick Howes on the Faulkes team said “When we first saw the preliminary orbit, we knew it was a quite remarkable object” Howes also added “To have a University Student also involved is terrific for the degree program at Glamorgan and also for the Faulkes project. We’d like to extend our congratulations to Al Grauer” for his detection of this groundbreaking new comet” and we’re immensely proud to be part of the CBET released by the IAU confirming its nature
Southern Hemisphere of Vesta; Rheasilvia and Older Basin. Colorized shaded-relief map showing identification of older 375-kilometer-wide impact basin beneath and overlapping with the more recent Rheasilvia impact structure at asteroid Vesta’s South Pole. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
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Scientists leading NASA’sDawn mission have discovered a 2nd giant impact basin at the south pole of the giant asteroid Vesta, which has been unveiled as a surprisingly “dichotomous” and alien world. Furthermore, the cosmic collisions that produced these two basins shuddered through the interior and created vast Vestan troughs, a Dawn scientist told Universe Today.
The newly discovered impact basin, nicknamed ‘Older Basin’, is actually significantly older in age compared to the initially discovered South Pole basin feature named ‘Rheasilvia’ – perhaps by more than a billion years. And that is just one of the many unexplained mysteries yet to be reconciled by the team as they begin to sift through the millions of bits of new data streaming back daily to Earth.
Scientists speculate that ‘Older Basin’ is on the order of 3.8 Billion years old, whereas ‘Rheasilvia’ might be as young as about 2.5 Billion years, but those are just tentative estimates at this time and subject to change. Measurements so far indicate Rheasilvia is composed of basaltic material.
Shaded-relief topographic map of Vesta southern hemisphere showing two large impact basins - Rheasilvia and Older Basin.
Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
“We found many surprising things at Vesta, which is quite unique and the results have exceeded our expectations”, said Dr. Carol Raymond, Dawn deputy principal investigator, of NASA’s Jet Propulsion Laboratory, Pasadena, Calif.
Researchers presented the latest findings from Dawn’s initial science mapping orbit at a news briefing at the annual meeting of the Geological Society of America in Minneapolis, Minn., on Oct. 13.
The team considers Vesta to be the smallest terrestrial planet.
Since achieving orbit in July, Dawn’s Framing Cameras (FC) have imaged most of Vesta at about 250 meter resolution and the Visible and Infrared mapping spectrometer(VIR) at about 700 meter resolution. The measurements were collected at the survey orbit altitude of 2700 km. Before Dawn, Vesta was just a fuzzy blob in humankind’s most powerful telescopes.
Vesta from Hubble (top) as a fuzzy blob and from Dawn in orbit (bottom) in crystal clear high resolution.
Credit: NASA/JPL-Caltech/ UCLA/MPS/DLR/IDA
“There is a global dichotomy on Vesta and a fundamental difference between the northern and southern hemispheres”, said Raymond. “The northern hemisphere is older and heavily cratered in contrast to the brighter southern hemisphere where the texture is more smooth and there are lots of sets of grooves. There is a massive mountain at the South Pole. One of the more surprising aspects is the set of deep equatorial troughs.”
“There is also a tremendous and surprising diversity of surface color and morphology. The south is consistent with basaltic lithology and the north with impacts. We are trying to make sense of the data and will integrate that with the high resolution observations we are now collecting.”
Indeed Vesta’s completely unique and striking dichotomy can be directly traced back to the basins which were formed by ancient cataclysmic impacts resulting in shockwaves that fundamentally altered the surface and caused the formation of the long troughs that ring Vesta at numerous latitudes.
“The troughs extend across 240 degrees of longitude,” said Debra Buczkowski, Dawn participating scientist, of the Applied Physics Laboratory at Johns Hopkins University, Laurel, Md. “Their formation can be tied back to the two basins at the South Pole.”
Asteroid Vesta and Equatorial Grooves
This full view of the giant asteroid Vesta was taken by NASA’s Dawn spacecraft, as part of a rotation characterization sequence on July 24, 2011, at a distance of 3,200 miles (5,200 kilometers). A rotation characterization sequence helps the scientists and engineers by giving an initial overview of the character of the surface as Vesta rotated underneath the spacecraft. This view of Vesta shows impact craters of various sizes and grooves parallel to the equator. The resolution of this image is about 500 meters per pixel. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
In an exclusive follow up interview with Universe Today, Raymond said “We believe that the troughs formed as a direct result of the impacts,” said “The two sets of troughs are associated with the two large basins [Rheasilvia and Older Basin].”
“The key piece of evidence presented was that the set of troughs in the northern hemisphere, that look older (more degraded) are circumferential to the older impact basin,” Raymond told me.
“The equatorial set are circumferential to Rheasilvia. That Rheasilvia’s age appears in places to be much younger is at odds with the age of the equatorial troughs. An explanation for that could be resurfacing by younger mass wasting features (landslides, slumps). We will be working on clarifying all these relationships in the coming months with the higher resolution HAMO (High Altitude Mapping Orbit) data.”
Dawn has gradually spiraled down closer to Vesta using her exotic ion thrusters and began the HAMO mapping campaign on Sept. 29.
Surface features are dated by crater counting methodology.
“Preliminary crater counting age dates for the equatorial trough region yields a very old age (3.8 Billion years). So there is a discrepancy between the apparent younger age for the Rheasilvia basin and the old age for the troughs. These could be reconciled if Rheasilvia is also 3.8 Billion years old but the surface has been modified by slumping or other processes,” Raymond elaborated.
Time will tell as further data is analyzed.
Dawn launch on September 27, 2007 by a Delta II Heavy rocket from Cape Canaveral Air Force Station, Florida. Credit: Ken Kremer
“Vesta is full of surprises, no more so than at the South Pole,” said Paul Schenk at the GSA briefing. Schenk is a Dawn participating scientist of the Lunar and Planetary Institute, Houston, Texas.
The ‘Rheasilvia’ basin was initially discovered in images of Vesta taken a decade ago by the Hubble Space Telescope which revealed it as a gaping hole in the southern hemisphere. But it wasn’t until Dawn entered orbit on July 16, 2011 after a nearly four year interplanetary journey that Earthlings got their first close up look at the mysterious polar feature and can now scrutinize it in detail to elucidate its true nature.
“The South Pole [Rheasilvia] basin is a roughly circular, impact structure and a deep depression dominated by a large central mound,” said Schenk. “It shows sharp scarps, smooth areas, landslide deposits, debris flows. It’s about 475 km in diameter and one of the deepest (ca. 20 -25 km) impact craters in the solar system.”
The central peak is an enormous mountain, about 22 km high and 180 km across- one of the biggest in the solar system. “It’s comparable in some ways to Olympus Mons on Mars,” Schenk stated.
“We were quite surprised to see a second basin in the mapping data outside of Rheasilvia. This was unexpected. It’s called ‘Older Basin’ for now.”
‘Older Basin’ is about 375 km in diameter. They overlap at the place where Rheasilvia has a missing rim.
“These basins are interesting because we believe Vesta is the source of a large number of meteorites, the HED meteorites that have a spread of ages,” Schenk explained.
Images showing key components of Rheasilvia impact basin on Vesta in high resolution ,referred to Shaded-relief topographic map. Credit: NASA/JPL-Caltech/ UCLA/MPS/DLR/IDA
Multiple large impacts over time may explain the source of the HED (Howardite, Eucrite and Diogenite) meteorites.
“We did expect large impacts on Vesta, likely associated with the late heavy bombardment recognized in the lunar impact record,” Raymond told Universe Today. “The surprising element is that the two apparently largest impacts – keeping in mind that other larger impact basins may be lurking under the regolith – are overlapping.”
Dawn’s VIR spectrometer has detected pyroxene bands covering Vesta’s surface, which is indicative of typical basaltic material, said Federico Tosi, a VIR team member of the Italian Space Agency, Rome. “Vesta has diverse rock types on its surface.”
“VIR measured surface temperatures from 220K to 270 K at the 5 micron wavelength. The illuminated areas are warmer.”
So far there is no clear indication of olivine which would be a marker for seeing Vesta’s mantle, Tossi elaborated.
The VIR spectrometer combines images, spectral information and temperature that will allow researchers to evaluate the nature, composition and evolutionary forces that shaped Vesta’s surface.
The team is absolutely thrilled to see a complicated geologic record that’s been preserved for study with lots of apparent surface layering and surprisingly strong and complex structural features with a large range of color and brightness.
Stay tuned for a year of Vestan delights !
Asteroid Vesta from Dawn
South Pole Rheasilvia basin is at lower right. NASA's Dawn spacecraft obtained this image of the giant asteroid Vesta with its framing camera on July 24, 2011 from a distance of about 3,200 miles (5,200 kilometers). Dawn entered orbit around Vesta on July 16, and will spend a year orbiting the body.
Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
Here’s a great talk given by our friend Phil Plait at a TED event, TEDxBoulder, about how an asteroid might one day give us Earthlings a really bad day. But he’s got good news, too: We have a space program!
Oblique View of Vesta's South Polar Region - Rheasilvia. This image of the asteroid Vesta, calculated from a shape model, shows a tilted view of the topography of the south polar region. The image has a resolution of about 1,000 feet (300 meters) per pixel, and the vertical scale is 1.5 times that of the horizontal scale. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI
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NASA has just released an amazing new view of the mysterious south pole of Vesta that offers an oblique perspective view of the central mountain peak which is three times as high as Mt Everest. This topographic view , shown above,is completely unique to viewers from Earth and is provided courtesy of NASA’s exotic Dawn Asteroid Orbiter – newly arrived in July 2011.
The mountain peak rises about 15 miles (22 km) above the average height of the surrounding pockmarked terrain at Vesta’s south polar region – formally named Rheasilvia – and is located in the foreground, left side of the new image. A portion of the crater rim with a rather steep slope – known as a scarp – is seen at the right and may show evidence of Vestan landslides.
This oblique image derived from the on board Framing Camera was created from a shape model of the 530 km diameter asteroid. It has been flattened to remove the curvature of Vesta and has a vertical scale adjusted to 1.5 times that of the horizontal scale.
The origin of Vesta’s south polar region is hotly debated among the mission’s science team who will reveal their current theories at a briefing set for October 12 – watch for my upcoming report.
Dawn will remain in orbit at Vesta for 1 year until July 2012 and then fire up its revolutionary ion propulsion system to depart for Ceres, the largest Asteroid in the main belt between Mars and Jupiter.
Asteroid Vesta from Dawn
NASA's Dawn spacecraft obtained this image of the giant asteroid Vesta with its framing camera on July 24, 2011. It was taken from a distance of about 3,200 miles (5,200 kilometers). Dawn entered orbit around Vesta on July 15, and will spend a year orbiting the body. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
(Left to right): images of (596) Scheila corresponding to 2010 December 13, 14, 17, and 29. The upper row corresponds to the observations, while the lower row to the models. The tails clearly show a bifid pattern with a central spike in the sunward direction, although it is not detectable in the December 29 image. Except for this latter case, the modeled images are rendered using the same color code for the intensities as the corresponding observed images in the top row. Credit: Fernando Moreno
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On December 12, 2010, something very unusual happened to asteroid Scheila. For a short period of time, its appearance changed dramatically and it even developed a comet-like tail. Now a group of international scientists headed by Fernando Moreno of the Instituto de Astrofísica de Andalucía in Granada, Spain have created a computer model which may explain this weird activity… an impact.
In results revealed October 7th in Nantes, France at the joint meeting of the European Planetary Science Congress and the American Astronomical Society’s Division for Planetary Sciences, the team explained their theory of how this innocent asteroid may have been crashed into by a smaller object. Moreno and his team plotted the brightness curve of Scheila’s newly developed “tail” – watching how it declined over a period of weeks. Their conclusion was that Scheila was either responsible for bumping into an uncatalogued object – or the object bumped into it causing a debris trail.
“The model we used involves a very large number of particles ejected from Scheila.” explains Moreno. “We took into account gravity from the Sun, pressure radiation on the ejected particles, and Scheila´s gravity, which has a strong effect on the particles in its vicinity owing to its large mass.”
Just when did this crash occur? The first indications placed the “asteroid accident” at a period of somewhere between November 11 and December 3, 2010. But, thanks to refined studies the team has placed the smash-up to on – or within – three days of November 27, 2010. With a size of about 110 kilometers across, Scheila isn’t very large and the impactor was estimated to be anywhere from 60 to 180 meters in diameter. That’s quite enough to send visible pieces flying into space!
“We applied a scaling law that uses impact velocity to indicate the mass of the impactor and ejected material.” concludes Moreno. “We know the impact should be about 5 kilometres per second because that’s the average velocity of asteroids in the Main Belt. Using this number we predicted both the ejection velocity of the particles (50 to 80 meters per second) and the size of the impactor.”
As for asteroid Scheila, she’s also a step off the beaten path, too. It belongs to a class known Main-Belt Comets – objects which have orbital characteristics of Main-Belt Asteroids – but sometimes behave like a comet. The reason why they have outbursts still isn’t clear. While these new modeling techniques may lend credence to the impact theory, there’s also a strong possibility of gaseous emissions. However, astronomers from the University of Maryland and Institute for Astronomy, University of Hawaii have ruled out venting in Scheila’s case.
With NASA’s announcement of its new, mammoth Space Launch System (SLS), preparations can begin in earnest for the first human mission to an asteroid. The SLS will take the Orion Multipurpose Crew Vehicle (MPCV) on the first human forays into deep space, out of the Earth/Moon system. “We are definitely excited about it,” Laurence Price, Lockheed Martin’s Orion deputy program manager told Universe Today during a briefing last week. “It is very good to get this baselined and be able to move forward.”
Lockheed Martin has been working on the Orion MPCV, which was originally part of the Constellation program to return to the Moon. But NASA has now been given a presidential directive to land astronauts on an asteroid by 2025, a mission that some say represents the most ambitious and audacious plan yet for the space agency. Orion will likely be re-worked and updated for potential “stepping stone” missions that will take humans to possible destinations such as lunar orbit, the Lagrange points, asteroids, and potentially the moons of Mars. The ultimate destination on this path is to send humans to the Red Planet.
Stepping stone destinations on the way to Mars. Credit: Lockheed Martin.
Billed as the biggest rocket ever built, the first incarnation of NASA’s SLS heavy-lift booster — which was unveiled on Sept. 14, 2011 — will stand over 30 stories tall, have a mass of 2.5 million kg (5.5 million pounds) and use a liquid hydrogen and liquid oxygen propulsion system, with 5 space shuttle main engines and an improved J-2X engine for the upper stage. (NASA just tested one of those engines). The SLS will have an initial lift capacity of 70 metric tons (mT), or about 69,853 kg (154,000 pounds) of payload into low Earth orbit. For reference, that’s more than double the lift capacity of any current launch vehicle, and it is estimated to be able to generate 10% more thrust than the Saturn 5 rockets produced at liftoff, the launchers that sent the Apollo missions to the Moon.
Later, to send the Orion and a service module out into space, the SLS would add two more RD-25D/E engines on the first stage, and the “evolved” architecture would be able to lift 130 metric tons, or 129,727 kg (286,000 pounds) of mass to low Earth orbit. This would increase the mass of the stack to 2.6 million kg (6.5 million pounds) and it would stand as tall as a 40-story building. This configuration would enable thrust of 4.2 million kg (9.2 million pounds), 20% more than the Saturn 5.
But Lockheed Martin is still in the initial stages of learning about the capabilities and timelines of the new launch system so they can produce the best version of Orion to pair with the SLS.
“While there are some challenges,” Price said, “we have been looking at various configurations of the architecture over the past year, so a lot of work has already been going on. So, any of the initial challenges, we have already worked toward mitigating.”
There are several differences between SLS and Constellation, Price said, with SLS having potentially a liquid booster with solid strap-ons instead of a solid first stage. “But we’ve been flying in space for 50 years and all the analytical tools to predict the environments, flight trajectories and flight conditions are all fairly straightforward, and we’re working to close on it. The launch vehicle design change is not a big perturbation on our ability to continue to mature the vehicle.”
In factoring the capability of how much mass the SLS can launch to deep space, Lockheed Martin can begin to work on how they would manifest the various parts of the mission.
“For example, would we launch the two spacecraft together on one rocket,” said Josh Hopkins from Lockheed Martin, in an interview with Universe Today, “and like Apollo, go to deep space quickly, or would we do what Constellation was planning, where you’d launch the larger pieces on the heavy lift vehicle and launch the crew separately on a second launch and connect them in Earth orbit?”
Hopkins is the Principal Investigator for Advanced Human Exploration Missions at Lockheed Martin, and leads a team of engineers who develop plans and concepts for a variety of future human exploration missions, including visits to asteroids.
The Orion casule in an Acoustic Chamber for testing at Lockheed Martin. Credit: Lockheed Martin
“If the two are launched separately,” Hopkins continued, “then you’d have to allocate a few days in orbit to have the two hook up, or one scrubbed launch could ruin the attempt. So those are the top level kinds of things we are looking forward to finding out from NASA. At the detailed level, we’re working on things like what the flight environments will be like, how much load will the spacecraft see. What we’ve inferred from the studies we’ve been doing is that we think that Orion is already designed to a pretty rigorous set of acoustics, dynamic pressure and G-loads during ascent.”
“We already know a lot about this vehicle, its environment, load conditions and trajectory,” Price said, “so we are accommodating the unique capability of the launch vehicle into the design of the Orion MPCV. We are already converging on how this vehicle will fly, and as soon as possible, we will transition to flying our test flights on early versions of the SLS.”
Lockheed Martin is targeting late 2013 or early 2014 for their first flight test of the Orion MPCV and they have reserved a Delta 4 Heavy for an unpiloted launch from Kennedy Space Center, but they are still evaluating what launcher would be best.
“We are identifying what the best test booster will be,” Price said, “and are trying to maximize the benefit to both programs, the launch system maturation and our spacecraft.”
An artist's concept shows the Orion Multipurpose Crew Vehicle and future destinations for human exploration beyond Earth orbit: the moon, an asteroid and Mars. Credit: NASA
As far as actually sending humans to an asteroid, there are many details to be worked out, and NASA and Lockheed Martin must allow for all the unknowns of flying humans in deep space, including a very important one of making sure humans can endure the radiation environment in space.
Hopkins said the robotic spacecraft that have flown to asteroids and Mars have tested the environment of deep space. “So, we have elegant models of how to design systems to withstand radiation shielding,” he said, “even though we don’t know the effect of deep space radiation on people, and what the environments around small asteroids actually like.” Hopkins added that redundant systems for keeping humans safe are an integral part of Orion’s design, but NASA might also first send a robotic scout mission to visit an asteroid.
Yes, there’s much to be worked out to actually send humans to an asteroid. But one initial item of importance is knowing the timing of when SLS will be ready to do a human deep space mission, as that would determine what asteroids we’d be able to go to.
And finding an asteroid that is just right is going to be a challenge, too. We’ll discuss that in the next in our series of articles on a human asteroid mission.
3 D Anaglyph of Craters at Rheasilvia - the South Polar Region of Vesta. This 3-D image shows the topography, craters and grooves of Vesta’s south polar region obtained by the framing camera instrument aboard NASA’s Dawn spacecraft on Aug. 23 and 28, 2011. The image has a resolution of about 260 meters per pixel.
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Try not to plummet off a steep crater cliff or be buried under a landslide while gazing at the irresistibly alluring curves of beautiful Rheasilvia – the mythical mother of Romulus and Remus – whose found a new home at the South Pole of the giant Asteroid Vesta.
3 D is undoubtedly the best way to maximize your pleasure. So whip out your cool red-cyan anaglyph glasses to enhance your viewing experience of Rheasilvia, the Snowman and more – and maximize your enjoyment of this new 3 D collection showcasing the heavily cratered, pockmarked, mountainous and groovy terrain replete at Vesta.
3D Details of Wave-Like Terrain in the South Pole of Vesta
This image was obtained by NASA’s Dawn spacecraft from an orbit of about 1,700 miles (2,700 kilometers) above the surface of the giant asteroid Vesta. Topography in the area surrounding Vesta's south pole area shows impact craters, ridges and grooves. These images in 3D provide scientists with a realistic impression of the solid surface of the celestial body.
Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
Can you find the location of the 3 D image above in the 2 D South Pole image below?
Scientists and mortals have been fascinated by the enormous impact crater Rheasilvia and central mountain unveiled in detail by NASA’s Dawn Asteroid Orbiter recently arrived at Vesta, the 2nd most massive object in the main asteroid belt. Ceres is the largest object and will be Dawn’s next orbital target in 2015 after departing Vesta in 2012.
3D - A Big Mountain at Asteroid Vesta’s South Pole
Scientists were fascinated by this enormous mound inside a big circular depression at the south pole- dubbed Rheasilvia. This stereo image was recorded from an altitude of about 1,700 miles (2,700 kilometers) above the surface and shows the structure of the mountain, displayed in the right half of this 3D image. The base of the mountain has a diameter of about 125 miles (200 kilometers), and its altitude above the surroundings is about 9 miles (15 kilometers). The vicinity of the peak of the mountain shows landslides that occurred when material from the flanks of the mountain were slipping down. Also visible are tectonic structures from tension in Vesta's crust. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
“Vesta is the smallest terrestrial planet in our Solar System”, said Chris Russell in an interview with Universe Today. “We do not have a good analog to Vesta anywhere else in the Solar System.”
And the best is yet to come. In a few days, Dawn begins snapping images from a much lower altitude at the HAMO mapping orbit of ca. 685 km vs the initial survey orbit of ca, 2700 km. where most of these images were taken.
Can you find the location of the 3 D South Pole images above in the 2 D South Pole image below?
Topography of Densely Cratered Deformed Terrain
This 3 D anaglyph image shows the topography of Vesta's densely cratered terrain obtained by the framing camera instrument aboard NASA's Dawn spacecraft on August 6, 2011. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDAAnaglyph of the ‘Snowman' Crater. This anaglyph image shows the topography of Vesta's three craters, informally named the "Snowman," obtained by the framing camera instrument aboard Dawn on August 6, 2011. The camera has a resolution of about 260 meters per pixel. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDAVesta's Ancient, Cratered Surface in 3D
This image of the giant asteroid Vesta obtained by NASA's Dawn spacecraft shows the surface of the asteroid from an orbit of about 1,700 miles (2,700 kilometers) above the surface. Numerous impact craters illustrate the asteroid's violent youth. By counting craters on distinct geological surfaces scientists can deduce relative ages of the asteroid's surface. This 3D view provides scientists the opportunity to learn more about the morphology of craters on asteroids and physical properties of the material at Vesta's surface.. Image resolution is about 260 meters per pixel. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDAViewing the South Pole of Vesta and Rheasilvia Impact Basin
This image obtained by Dawns framing camera shows the south pole of the giant asteroid Vesta. Scientists are discussing whether the Rheasilvia circular structure that covers most of this image originated by a collision with another asteroid, or by internal processes early in the asteroid's history. Images in higher resolution from Dawn's next lowered orbit might help answer that question. The image was recorded from a distance of about 1,700 miles (2,700 kilometers). The image resolution is about 260 meters per pixel. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDARhea Silvia, torso from the amphitheatre at Cartagena in Spain that was rediscovered in 1988. Rhea Silvia was the mother of Romulus and Remus, the mythical founders of Rome. Source: Wikipedia
Read Ken’s continuing features about Dawn and Vesta
NEEMO engineering crew diver simulates anchoring to an asteroid surface. Image credit: NASA
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The sight of NASA mission specialists performing mission training underwater has been fairly common over the years. On October 15th, NASA astronaut and former ISS crew member Shannon Walker will lead a different kind of underwater training mission. Walker will be leading the 15th expedition of NASA Extreme Environment Mission Operations (NEEMO), and interestingly, the crew includes Steve Squyres, head of the Mars Rover Exploration Project.
What makes NEEMO different from the other NASA underwater training simulations we’ve seen in the past?
Think asteroid.
With manned exploration of an asteroid on NASA’s roadmap, new technologies and procedures need to be created in order to ensure astronaut safety and achieve mission science goals. The NEEMO program at NASA will be putting experts to the task of developing solutions to the new challenges presented with near-Earth asteroid exploration. During NEEMO 15, NASA will test new tools, techniques and communication technologies.
Before now, NASA hasn’t given much thought to the operations necessary for a manned mission to an asteroid. With the nearly non-existent surface gravity of an asteroid, astronauts won’t be able to walk on the surface. One idea being tested is for the astronauts to anchor themselves to the asteroid. One difficulty with using anchors is that not all asteroids are made of the same materials – some asteroids are mostly metal, others are loose rubble and some are a mix of rock, metal and dust. Underwater testing on the ocean floor provides an environment that is perfectly suited for the NEEMO 15 mission, allowing NASA to simulate an environment with weak gravity and diverse materials.
Artist's concept of anchoring to the surface of an asteroid. Image credit: NASA
There are three main goals for the NEEMO 15 mission. First NASA will test methods for anchoring to the surface of the asteroid. Moving on the surface of an asteroid will require a method of connecting multiple anchors. The second major goal of the mission is to determine the best way to connect the anchor system. The third major goal will explore methods of collecting samples on the surface of an asteroid.
In addition to mission leader Shannon Walker, and Steve Squyres, the crew of NEEMO 15 includes astronaut Takuya Onishi (Japan Aerospace Exploration Agency) and David Saint-Jacques (Canadian Space Agency). Also joining the astronauts on the NEEMO 15 crew are: James Talacek and Nate Bender (University of North Carolina). Squyres is principal investigator for the Mars Exploration Rover (Spirit and Opportunity) mission, while Talacek and Bender are professional aquanauts.
Serving as support crew, NASA astronauts Stan Love, Richard Arnold and Mike Gernhardt, will participate in the NEEMO mission from the DeepWorker submersible, which they will pilot. NASA is using the DeepWorker submarine as an underwater stand-in for the Space Exploration Vehicle (SEV) which NASA has been testing separately in the “Desert RATS” field trial mission.
A False-Color Topography of Vesta's South Pole. This false-color map of the giant asteroid Vesta was created from stereo images obtained by the framing camera aboard NASA’s Dawn spacecraft. The image shows the elevation of surface structures with a horizontal resolution of about 750 meters per pixel. The terrain model of Vesta's southern hemisphere shows a big circular structure with a diameter of about 300 miles (500 kilometers), its rim rising above the interior of the structure for more than 9 miles (15 kilometers.) Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
Video caption: Rheasilvia Impact Basin and Vesta shape model. This false-color shape model video of the giant asteroid Vesta was created from images taken by the framing camera aboard NASA’s Dawn spacecraft. Rheasilvia – South Pole Impact Basin – shown at bottom (left) and head on (at right). Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
‘Rheasilvia’ – that’s the brand new name given to the humongous and ever more mysterious South Pole basin feature being scrutinized in detail by Dawn, according to the missions top scientists in a Universe Today exclusive. Dawn is NASA’s newly arrived science orbiter unveiling the giant asteroid Vesta – a marvelously intriguing body unlike any other in our Solar System.
What is Rheasilvia? An impact basin? A crater remnant? Tectonic action? A leftover from internal processes? Or something completely different? That’s the hotly debated central question consuming loads of attention and sparking significant speculation amongst Dawn’s happily puzzled international science team. There is nothing closely analogous to Vesta and Rhea Silvia – and thats a planetary scientists dream come true.
“Rheasilvia – One thing that we all agree on is that the large crater should be named ‘Rheasilvia’ after the mother of Romulus and Remus, the mythical mother of the Vestals,” said Prof. Chris Russell, Dawns lead scientist, in an exclusive interview with Universe Today. Russell, from UCLA, is the scientific Principal Investigator for Dawn.
“Since we have never seen any crater just like this one it is difficult for us to decide exactly what did happen,” Russell told me. “The name ‘Rheasilvia’ has been approved by the IAU and the science team is using it.”
Craters on Vesta are being named after the Vestal Virgins—the priestesses of the Roman goddess Vesta. Other features will be named for festivals and towns of that era. Romulus and Remus were the mythical founders of Rome.
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‘Rheasilvia’ has the science team in a quandary, rather puzzled and reevaluating and debating long held theories as they collect reams of new data from Dawn’s three science instruments – provided by the US, Germany and Italy. That’s the scientific method in progress and it will take time to reach a consensus.
Prior to Dawn’s orbital insertion in July 2011, the best views of Vesta were captured by the Hubble Space Telescope and clearly showed it wasn’t round. Scientists interpreted the data as showing that Vesta’s southern hemisphere lacked a South Pole! And, that it had been blasted away eons ago by a gargantuan cosmic collision that excavated huge amounts of material that nearly utterly destroyed the asteroid.
The ancient collision left behind a colossal 300 mile (500 km) diameter and circular gaping hole in the southern hemisphere – nearly as wide as the entire asteroid (530 km) and leaving behind an as yet unexplained and enormous central mountain peak, measuring some 9 miles (15 km) high and over 125 miles (200 km) in diameter. The mountain has one of the highest elevations in the entire solar system.
“We are trying to understand the high scarps that we see and the scarps that should be there and aren’t,” Russell explained. “We are trying to understand the landslides we think we see and why the land slid. We see grooves in the floor of the basin and want to interpret them.
“And the hill in the center of the crater remains as mysterious today as when we first arrived.”
Viewing the South Pole of Vesta and Rheasilvia Impact Basin
This image obtained by Dawns framing camera and shows the south pole of the giant asteroid Vesta. Scientists are discussing whether the Rheasilvia circular structure that covers most of this image originated by a collision with another asteroid, or by internal processes early in the asteroid's history. Images in higher resolution from Dawn's lowered orbit might help answer that question. The image was recorded from a distance of about 1,700 miles (2,700 kilometers). The image resolution is about 260 meters per pixel. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
Another top Dawn scientist described Rheasilvia in this way:
“I would say that the floor of the impact feature contains chaotic terrain with multiple sets of intersecting grooves, sometimes fairly straight and often curvy, said Carol Raymond to Universe Today. Raymond is Dawn’s Deputy Principal Investigator from NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
“The crater rim is not well-expressed”, Raymond told me. “We see strong color variations across Vesta, and the south pole impact basin appears to have a distinct spectral signature.
“The analysis is still ongoing,” Russell said.
“The south is distinctly different than the north. The north has a varied spectrum and the south has a distinct spectral feature but it has little variation.” Time will tell as additional high resolution measurements are collected from the forthcoming science campaign at lower orbits.
Russell further informed that the team is rushing to pull all the currently available data together in time for a science conference and public briefing in mid-October.
“We have set ourselves a target to gather everything we know about the south pole impact feature and expect to have a press release from what ever we conclude at the GSA (Geological Society of America) meeting on October 12. “We will tell the public what the options are.”
“We do not have a good analog to Vesta anywhere else in the Solar System and we’ll be studying it very intently.”
Impressive South Pole MountainTop at Rheasilvia Crater on Vesta
This mountain, which measures about 125 miles (200 kilometers) in diameter at its base, is one of the highest elevations on all known bodies with solid surfaces in the solar system. The image has been recorded with the framing camera aboard NASA's Dawn spacecraft from a distance of about 1,700 miles (2,700 kilometers). The image resolution is about 260 meters per pixel. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
Right now Dawn is using its ion propulsion system to spiral down four times closer to Vesta, as it descends from the initlal survey orbit(about 2700 km, 1700 mi) to the new science orbit, elegantly named HAMO – or High Altitude Mapping Orbit (about 685 km.)
“Our current plan is to begin HAMO on Sept. 29, but we will not finalize that plan until next week,” Dr. Marc Rayman told Universe Today. Rayman, of NASA’s JPL, is Dawn’s Chief Engineer.
“Dawn’s mean altitude today (Sept. 20) is around 680 km (420 miles),” said Rayman .
“Dawn successfully completed the majority of the planned ion thrusting needed to reach its new science orbit and navigators are now measuring its orbital parameters precisely so they can design a final maneuver to ensure the spacecraft is in just the orbit needed to begin its intensive mapping observations next week.”
Watch for lots more stories upcoming on Vesta and the Dawn mission
