The Venus Spokes Illusion
19th century American astronomer Percival Lowell is infamous for his claim that the surface of Mars is covered with an intricate system of non-natural canals, but it is less well known that he also reported controversial observations about Venus. From his observatory atop a remote mountain in Arizona, Lowell claimed to see a central dark spot on the cloud-shrouded planet, with an intricate systems of ‘spokes’ coming out of it. Lowell confidently sketched his discovery, saying they were beyond the possibility of an illusion and envisioning them as permanent surface features, but no one else could see them—and so, understandably, the astronomical community was skeptical. Lowell argued for many years that their technology was simply inferior to his own remote mountainous set-up, but as the years went on, no other evidence was produced, and Lowell’s passionate claims were dismissed. The mystery of what he really saw was finally solved in 2003, when an optometrist Sherman Schultz suggested that the spokes Lowell saw were actually the shadow of his own blood vessels cast onto his retina. So, instead of mapping other planets, Lowell actually spent part of his career mapping the structure of his own eye.
During the past week, nightfall on planet Earth has featured Mars, Saturn, and Spica in a lovely conjunction near the western horizon. Still forming the corners of a distinctive celestial triangle after sunset and recently joined by a crescent Moon, they are all about the same brightness but can exhibit different colors to the discerning eye. This ingenious star trail image was recorded as the trio set on August 12 with a telephoto lens from the shores of Lake Eppalock, in central Victoria, Australia. Focused on foreground eucalyptus trees, the image slightly blurs the trails to show more saturated colors. Can you guess which trail is which? Of course the reddest trail is Mars, with Saturn on the right a paler echo of the Red Planet’s hue. Left is hot and luminous Spica, bluish alpha star of the constellation Virgo.
Image Credit & Copyright: Phil Hart
Viking 1 Launch Anniversary
Viking 1 was the first of two spacecraft sent to Mars as part of NASA’s Viking program. It was the first spacecraft to successfully land on Mars and perform its mission, and held the record for the longest Mars surface mission of 6 years and 116 days (from landing until surface mission termination, Earth time) until that record was broken by the Opportunity Rover on May 19, 2010.
Viking 1 launched aboard a Titan IIIE rocket August 20, 1975 and arrived at Mars on June 19, 1976. The first month was spent in orbit around the martian planet and on July 20, 1976 Viking Lander 1 separated from the Orbiter and touched down at Chryse Planitia.
Curiosity on Mars: A Wall of Gale Crater
If you could stand on Mars, what would you see? The above image is a digitally re-colored approximation of what you might see if the above Martian landscape had occurred on Earth. Images from Mars false-colored in this way are called white balanced and useful for planetary scientists to identify rocks and landforms similar to Earth. The image is a high resolution version of a distant wall of Gale Crater captured by the Curiosity rover that landed on Mars last week. A corresponding true color image exists showing how this scene actually appears on Mars. The robotic Curiosity rover continues to check itself over and accept new programming from Earth before it begins to roll across Mars and explore a landscape that has the appearance of being an unusually layered dried river bed.
Image Credit: NASA, JPL-Caltech, MSSS
Curiosity in Exaggerated Color
This color-enhanced view of NASA’s Curiosity rover on the surface of Mars was taken by the High Resolution Imaging Science Experiment (HiRISE) on NASA’s Mars Reconnaissance Orbiter as the satellite flew overhead. Colors have been enhanced to show the subtle color variations near the rover, which result from different types of materials.
The descent stage blast pattern around the rover is clearly seen as relatively blue colors (true colors would be more gray).
Image credit: NASNASA/JPL-Caltech/University of Arizona
Cost of Olympics vs. Landing a robot on Mars
A Hole in Mars
What created this unusual hole in Mars? The hole was discovered by chance on images of the dusty slopes of Mars’ Pavonis Mons volcano taken by the HiRISE instrument aboard the robotic Mars Reconnaissance Orbiter currently circling Mars. The hole appears to be an opening to an underground cavern, partly illuminated on the image right. Analysis of this and follow-up images revealed the opening to be about 35 meters across, while the interior shadow angle indicates that the underlying cavern is roughly 20 meters deep. Why there is a circular crater surrounding this hole remains a topic of speculation, as is the full extent of the underlying cavern. Holes such as this are of particular interest because their interior caves are relatively protected from the harsh surface of Mars, making them relatively good candidates to contain Martian life. These pits are therefore prime targets for possible future spacecraft, robots, and even human interplanetary explorers.
Image Credit: NASA, JPL, U. Arizona
Mars Pathfinder Landed July 4, 1997
Mars Pathfinder (MESUR Pathfinder) was an American spacecraft that landed a base station with a roving probe on Mars in 1997. It consisted of a lander, renamed the Carl Sagan Memorial Station, and a lightweight (10.6 kilograms/23 pounds) wheeled robotic rover named Sojourner.
Launched on December 4, 1996 by NASA aboard a Delta II booster a month after the Mars Global Surveyor was launched, it landed on July 4, 1997 on Mars’ Ares Vallis, in a region called Chryse Planitia in the Oxia Palus quadrangle. The lander then opened, exposing the rover which conducted many experiments on the Martian surface. The mission carried a series of scientific instruments to analyze the Martian atmosphere, climate, geology and the composition of its rocks and soil. It was the second project from NASA’s Discovery Program, which promotes the use of low-cost spacecraft and frequent launches under the motto “cheaper, faster and better” promoted by the then administrator, Daniel Goldin. The mission was directed by the Jet Propulsion Laboratory (JPL), a division of the California Institute of Technology, responsible for NASA’s Mars Exploration Program. The project manager was JPL’s Tony Spear.
This mission was the first of a series of missions to Mars that included rovers, and was the next successful lander since the two Vikings landed on the red planet in 1976. Although the Soviet Union successfully sent rovers to the Moon as part of the Lunokhod program in the 1970s, its attempts to use rovers in its Mars probe program failed.
In addition to scientific objectives, the Mars Pathfinder mission was also a “proof-of-concept” for various technologies, such as airbag-mediated touchdown and automated obstacle avoidance, both later exploited by the Mars Exploration Rovers. The Mars Pathfinder was also remarkable for its extremely low cost relative to other unmanned space missions to Mars. Originally, the mission was conceived as the first of the Mars Environmental Survey (MESUR) program.
Making Tracks on Mars
In 1976, when two Viking spacecraft landed safely on Mars, few could have predicted that it would be nearly two decades before another spacecraft followed them successfully to the surface of the Red Planet. Fifteen years ago this week, Mars Pathfinder bounced onto the chilly surface of Mars, protected by inflatable landing bags. Pathfinder soon righted itself, unfolded its three solar panel petals, and deployed the remote-controlled Sojourner rover—the first wheeled vehicle to travel on Mars. The eleven kilogram (twenty-five pound) Sojourner operated for eighty-four days—twelve times its planned life—and traveled over 100 meters (300 feet). This view of the lander, renamed the Carl Sagan Memorial Station, was taken by Sojourner after it descended the ramp onto the surface.
Image credit: NASA / JPL / Caltech
Readying Orion for Flight
The NASA team at the Michoud Assembly Facility in New Orleans has completed the final weld on the first space-bound Orion capsule. The Exploration Flight Test 1 (EFT-1) Orion will be shipped to the Kennedy Space Center for final assembly and checkout operations.
The EFT-1 flight will take Orion to an altitude of more than 3,600 miles, more than 15 times farther away from Earth than the International Space Station. Orion will return home at a speed of 25,000 miles, almost 5,000 miles per hour faster than any human spacecraft. It will mimic the return conditions that astronauts experience as they come home from voyages beyond low Earth orbit. As Orion reenters the atmosphere, it will endure temperatures up to 4,000 degrees F., higher than any human spacecraft since astronauts returned from the moon.
Image Credit: NASA/Eric Bordelon
This enhanced-color image from March 2012 of a region of Mars near Nili Fossae shows part of the ejecta from an impact crater and contains some of the best exposures of ancient bedrock on Mars.
The impact broke up already diverse rocks types and mixed them together to create this wild jumble of colors, each representing a different type of rock.
This image was taken by the Mars Reconnaissance Orbiter’s HiRISE camera.
Image Credit: NASA/JPL-Caltech/University of Arizona
(via Mars Rocks)
Dark Shadows on Mars: Scene from Durable NASA Rover
Like a tourist waiting for just the right lighting to snap a favorite shot during a stay at the Grand Canyon, NASA’s Mars Exploration Rover Opportunity has used a low sun angle for a memorable view of a large Martian crater.
The resulting view catches a shadow of the rover in the foreground and the giant basin in the distance. Opportunity is perched on the western rim of Endeavour Crater looking eastward. The crater spans about 14 miles (22 kilometers) in diameter. Opportunity has been studying the edge of Endeavour Crater since arriving there in August 2011.
The scene is presented in false color to emphasize differences in materials such as dark dunes on the crater floor. This gives portions of the image an aqua tint.
Opportunity took most of the component images on March 9, 2012, while the solar-powered rover was spending several weeks at one location to preserve energy during the Martian winter. It has since resumed driving and is currently investigating a patch of windblown Martian dust near its winter haven.
Opportunity and its rover twin, Spirit, completed their three-month prime missions on Mars in April 2004. Both rovers continued for years of bonus, extended missions. Both have made important discoveries about wet environments on ancient Mars that may have been favorable for supporting microbial life. Spirit stopped communicating in 2010. Since landing in the Meridiani region of Mars in January 2004, Opportunity has driven 21.4 miles (34.4 kilometers).
NASA’s Jet Propulsion Laboratory, a division of the California Institute of Technology, in Pasadena, manages the Mars Exploration Rover Project for NASA’s Science Mission Directorate, Washington.
Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
Flowing Barchan Sand Dunes on Mars
When does Mars act like a liquid? Although liquids freeze and evaporate quickly into the thin atmosphere of Mars, persistent winds may make large sand dunes appear to flow and even drip like a liquid.
Visible on the above image right are two flat top mesas in southern Mars when the season was changing from Spring to Summer. A light dome topped hill is also visible on the far left of the image. As winds blow from right to left, flowing sand on and around the hills leaves picturesque streaks.
The dark arc-shaped droplets of fine sand are called barchans, and are the interplanetary cousins of similar Earth-based sand forms. Barchans can move intact a downwind and can even appear to pass through each other. When seasons change, winds on Mars can kick up dust and are monitored to see if they escalate into another of Mars’ famous planet-scale sand storms.
cool picture and nice read