Mars orbiter sends close-up photos of Comet Siding Spring

High resolution image pairs made with HiRISE camera on MRO during Comet Siding Spring’s closest approach to Mars on October 19. Shown at top are images of the nucleus region and inner coma. Those at bottom were exposed to show the bigger coma beginning of a tail. Credit: NASA/JPL/Univ. of Arizona

They’ve done it again. NASA engineers and scientists successfully slewed the Mars Reconnaissance Orbiter into position to get pictures of comet C/2013 Siding Spring during its close flyby on October 19. I think all of us were waiting for pictures more like this one which show more than a bit of fuzz. Not to disrespect fuzz. Fuzz or comet dust seeded the early Earth with important organic compounds and still makes for awesome meteor showers right up to the present day.

The top set of photos uses the full dynamic range of the camera to accurately depict brightness and detail in the nuclear region and inner coma. Prior to its arrival near Mars astronomers estimated the diameter of the nucleus or comet’s core at around 0.6 mile or 1 kilometer. But based on these images taken at much closer range, its true size is less than 1/3 mile or 0.5 km across. The bottom photos overexpose the nuclear region but reveal an extended coma and a short tail extending to the right.

The Edgeworth-Kuiper Belt extends outward from the plane of the planets, while the Oort Cloud encompasses the solar system in a spherical shell containing millions of comets. Long-period comets like C/2013 A1 Siding Spring often have diagonal orbits that cut across the plane.
Credit: NAOJ

Comet Siding Spring is a new visitor to the inner solar system, hailing from the distant repository of comets called the Oort Cloud far past Neptune and the icy asteroids that populate the Kuiper Belt.

It slid sunward on its cigar-shaped orbit for millions of years as the planets wheeled around the Sun like balls in a roulette wheel. By pure chance, Mars happened to lie only 87,000 miles from the comet on its journey toward the Sun.

Annotated photo of Comet Siding Spring taken by the Opportunity Rover on October 19 near closest approach. The comet passed comet passed much closer to Mars than any previous known comet flyby of Earth or Mars. Credit: NASA/JPL-Caltech/Cornell Univ./ASU/TAMU

Photographing a fast-moving target from orbit is no easy trick. You have to pan the MRO’s camera at the precise rate needed to shoot a time exposure without blurring the image. Engineers at Lockheed-Martin in Denver did exactly that based on comet position calculations by engineers at the Jet Propulsion Lab. To make sure they knew exactly where the comet was, the team photographed the comet 12 days in advance. To their surprise, the orbital calculations were just a bit off. Using the new positions, MRO succeeded in locking onto the comet during the flyby. Without this earlier check, cameras may have missed seeing Siding Spring altogether!

I’ve also added a new, annotated version of the photo taken by the Opportunity Rover and used in the blog earlier today. From the rover’s point of view, the comet buzzed across the constellation Cetus at the time, while here on Earth we see it in the summertime constellation Ophiuchus.

NASA deserves a pat on the back for their great work in acquiring these images and getting them to us within 24 hours. There will be much more on the observational side (and hopefully more photos!) in the weeks and months to come.

Opportunity Rover takes first pictures of Comet Siding Spring from Mars

Comet Siding Spring photographed October 19, 2014 by the Opportunity Rover. Stars show as point and the streaks are probably cosmic ray hits on the sensor during the exposure. Click for original. Credit: NASA/JPL-Caltech

Darn rover’s been there more than 10 years and still producing firsts. Around 4:13 a.m. local time October 19, not long before the beginning of morning twilight, NASA’s Opportunity Rover pointed its panoramic camera at Comet Siding Spring in the constellation Eridanus and took a historic photograph – the first of a comet seen from the surface of another planet.

Another photo of the comet taken by Opportunity. Click for original. Credit: NASA/JPL-Caltech

Sure, it’s just a fuzzy spot, but like Galileo’s first look at Jupiter through his primitive telescope, remarkable all the same. I found the photos while digging through the raw images posted on the Opportunity website earlier this morning. There were only three of the night sky, one of which clearly showed a fuzzy object. If you look closely, the comet looks elongated. That might be from trailing during the time exposure or could be a hint of its tail.

Time exposure of the night sky taken by NASA’s Curiosity Rover on October 19. You can see real stars if you look closely but most of the specks are noise. No sign of the comet. Credit: NASA/JPL-Caltech

Unfortunately I couldn’t find the comet in the several pictures returned by the Curiosity Rover. Each is heavily speckled with noise but no matter how I tried to tone and stretch the photos, no comet. Maybe NASA has other pictures it will offer after they’re cleaned up.

Map showing the landing sites of rovers and probes successfully landed on Mars. Opportunity is located 1.9 degrees south of the Martian equator in the dark feature called Sinus Meridiani. Credit: NASA

I should emphasize here that we’re still awaiting confirmation from NASA that these pictures really do show the comet, but it appears to be the real thing.

Next to a greatly overexposed Mars, we see Comet Siding Spring continuing on its way today October 20, 2014. Copyright: Rolando Ligustri

Crescent moon joins a planet parade / Opportunity ready for marathon run

The moon scoots by two bright stars and two bright evening planets in the next few nights. This map shows the sky facing southwest in late evening twilight. Stellarium

The moon joins a lineup of planets and bright stars hung like tiki lamps across the southwestern sky at dusk. Watch for it to pass near fading Mars Saturday evening and Saturn on Monday.

The Martian landscape photographed by on July 30, 2014. The rover is exploring south along the west rim of Endeavour Crater heading toward a notch called ‘Marathon Valley’ about 1.2 miles (2 kilometers) away. Credit: NASA/JPL

While you’re gazing at the Red Planet, know that the Opportunity rover made news this week when it set a record for the most miles ever driven off-planet, tallying a satisfying 25 miles (40 km) of Martian travels. The previous record was held by the Soviet Union’s Lunokhod 2 rover when it ambled across 24.2 miles of the moon’s surface in 1973.

Out of this world distance records compared. Credit: NASA

Opportunity surpassed that record on Monday July 28 when it registered 25.01 miles en route to a notch called Marathon Valley along the west rim of Endeavour Crater. Mission controllers would like to get a look at clay minerals there that have been spotted from orbit.

Lunokhod 2 crater photographed by Opportunity last spring. The crater’s 20 feet (6 meters) in diameter. Credit: NASA/JPL

When it reaches the Valley it will have completed 26.2 miles (42 km), the official distance of a marathon. When you consider that Opportunity and its sister probe Spirit were only intended to function for 90 days, the current record-breaking feat and upcoming marathon completion are that more remarkable.

Opportunity rover gets a free car wash / Mars back up, almost hits Porrima

A self-portrait of NASA’s Mars Exploration Rover Opportunity taken in late March 2014 (right) shows how fortuitous winds in late March cleaned much of the accumulated dust off the rover’s solar panels. Compare to a similar portrait from January 2014 (left). Click to enlarge. NASA/JPL-Caltech/Cornell Univ./Arizona State Univ.

What a difference a windy day can make. Before and after self-portraits dramatically show how gusty Martian winds swept away months of dust that had accumulated on the Opportunity rover’s solar panels.

Photo taken by the Opportunity rover looking east over the rim of the 14-mile-wide Endeavour Crater in March 2012. Winds blowing up over the crater’s rim in March removed much of the Mars grime coating the robot. Credit: NASA

Strong winds blowing over the rim of Endeavour Crater in mid-March removed almost all of the accumulated dust, increasing the power available from 375 watt-hours in January to more than 620 watt-hours per day by mid-April or about 80% of maximum. In fact, the rover now has cleaner solar arrays than in any Martian winter since it first landed on the Red Planet in 2005.

In a similar move, rains recently removed the accumulated road salt from my car deposited during the long winter. It’s now about 70% back to its original appearance. Opportunity ‘cleaning events’, as they’re called, happen periodically, and have played a significant role in the rovers’ longevity. Mars’ winds typically blow 20 mph with maximum speeds recorded by the 1970s Viking landers of 60 mph.

With extra juice to power its instruments, Opportunity can continue exploring Murray Ridge on the western rim of Endeavor Crater. Can you believe the rover’s been rolling around the Red Planet for more than 10 years now?

During Opportunity’s first decade on Mars and the 2004-2010 career of its twin, Spirit, the hardy robots have shown that Mars was once wet with both acidic waters and milder, more neutral ones conducive to supporting life.

Mars is still in retrograde motion, moving to the west directly underneath the beautiful double star Porrima (Gamma Virginis) in Virgo. Beginning in mid-May, the planet resumes its normal movement to the east. Created with Chris Marriott’s SkyMap program

While we’re on the topic of Mars, you may have noticed that the planet has been moving in the wrong direction since early March. The outer planets normally track east across the sky as they orbit the sun, but around the time of opposition, when they’re closest to Earth, they reverse gears and travel west in retrograde motion.

As Earth speeds past Mars, the planet appears to ‘drop behind’ or move westward for a time before resuming its normal motion. Credit: NASA

Of course, Mars didn’t really stop and change directions. It only appears that way as the faster Earth laps the slower-moving planet. Like passing a slower car, Mars appears for a time to travel backwards from our perspective. Once Earth moves far enough ahead of Mars – rounding the corner of our orbit as it were – the Red Planet resumes its normal eastward movement.

All the outer planets move more slowly around the sun than Earth and show retrograde motion, but the farther the planet, the smaller the loop. Mars scrawls a bigger loop because it’s closest.

This year’s retrograde amble takes Mars only a degree from Porrima, an attractive, closely paired double star in Virgo.

They’ll be closest later this week on May 2-3. Small telescope owners can use Mars to find Porrima. At low magnification, it looks like a single star, but increase the power to 100x and higher and you’ll see twin pearls of starlight.

Porrima is a true double star where each member orbits a common center of gravity. Diagram at right shows the orbit of the secondary companion around the primary star. The two were too close together to split in any but the largest telescopes in 2005. Since then they’ve been opening up. Credit: Damian Peach (left), www.dibonsmith.com (right)

Porrima’s stellar twins are similar to the sun but hotter and nearly identical in size. They go around each other every 169 years in an elliptical orbit that makes their separation narrow and widen as seen from Earth. The stars were closest in 2005 when they were separated by about 500 million miles, equal to Jupiter’s distance from the sun. They’ll be over 7 billion miles apart around the year 2080.

Mars and Porrima – also known as Gamma Virginis – tonight April 27 around 10 o’clock local time. Mars also passed the star on Dec. 29, 2013 moving east. Stellarium

Mars Opportunity Rover makes a juicy discovery

Like an insect adapted to its environment, the Opportunity Rover wears a near-perfect camouflage of red Mars dust in this mosaic self-portrait taken Jan. 3-6, 2014. The robot-that-could celebrates 10 years on Mars today. It was originally planned to operate for only 90 days. Click to enlarge. Credit: NASA/JPL-Caltech

Ten years ago this evening, NASA’s Opportunity Rover parachuted to the surface of Mars and settled on the red, iron-stained soil of Meridiani Planum. That iron was likely deposited eons ago in hot springs and steaming pools of superheated water. If Yellowstone National Park comes to mind, this now-dusty, chill and wind-swept place may once have been its cousin.

Researchers used the rover to find water-related minerals on the ground that had been detected from orbit. After brushing the rocks free of dust, Opportunity found this dark rocky veneer (center)  in the Whitewater Lake outcrop on Matijevic Hill. Credit: NASA/JPL-Caltech/Cornell Univ./Arizona State Univ.

After traveling 24 miles (38.7 km) spread over all those years, today Opportunity sits perched on the rim of 14-mile-wide Endeavour Crater near an area called Matijevic Hill. Beginning in 2010, the rover used its Compact Reconnaissance Imaging Spectrometer there to find brand new evidence of a ancient wet environment that was milder and older than the acidic and oxidizing conditions seen in other places examined by the rover.

Opportunity detected an iron-rich clay mineral known as smectite. Researchers believe the wet conditions that produced the smectite preceded the formation of the Endeavor Crater about 4 billion years ago. Anyone who’s gotten their foot stuck in slippery, juicy clay knows that it’s intimately associated with water.

“There’s more good stuff ahead,” said Steve Squyres of Cornell University, Ithaca, N.Y., the mission’s principal investigator. “We are examining a rock right in front of the rover that is unlike anything we’ve seen before. Mars keeps surprising us, just like in the very first week of the mission.”

Opportunity photographs the “mystery rock” on the rim of Endeavour Crater on Sol 3541. Click for more photos. Credit: NASA/JPL-Caltech

That rock is the “mystery rock” that rather suddenly appeared in front of the rover several weeks ago. I’ve included a more recent closeup of it for your enjoyment.

You can keep track of what the mission team is photographing by stopping by the Opportunity raw images site. Pick the camera and the Mars day or Sol number (today Jan. 24 is Sol 3556 for Opportunity) and have a look. One Sol = one Martian day or 24 hours 37 minutes. Anytime you want to know what Sol or what the local time is at either Opportunity or Curiosity lander locations, be sure to check out James Tauber’s delightful Mars Clock.

Mystery rock ‘materializes’ in front of Opportunity Rover, scientists scratch heads

A comparison of two raw Pancam photographs from Sols 3528 and 3540 shows a new rock about 3-inches across suddenly appearing out of nowhere a few feet in front of the rover. A Sol is a Martian day which is equal to 24 hours 37 minutes.  Credit: NASA/JPL-Caltech

Whoa – wait a minute. The first picture taken by the Opportunity Rover shows no rock. The second, taken of the exact same spot 12 Mars days later, shows a very real rock. How’d that get there?

The shadow of the Opportunity Rover stretches across the barren Martian landscape. Credit: NASA/ JPL-Caltech

The discovery was revealed by Mars Exploration Rover (MER) lead scientist Steve Squyres in a 10 years of Roving Mars keynote address at NASA’s Jet Propulsion Laboratory last night. MER scientists immediately named the new rock “Pinnacle Island”.

Scientists are still scratching their heads as to how that rock could move, but there are two intriguing possibilities, one of them unlikely and another so ordinary, it almost has to be true.

Squyres thinks it’s either a stone blown out from a meteorite impact that happened to land in front of the rover or, more likely, a rock flicked like a tiddlywink when the rover performed a turn in place not far from where the rock now lies. Or the rock got stuck earlier in a rover wheel and dropped out during the maneuver.

A higher resolution view of the mystery rock photographed by the Opportunity Rover. Credit: NASA/JPL-Caltech

Not ones to miss a scientific opportunity, Opportunity scientists hope to study the bright rock. “It obligingly turned upside down, so we’re seeing a side that hasn’t seen the Martian atmosphere in billions of years, and there it is for us to investigate. It’s just a stroke of luck,” Squyres said.

Opportunity’s front right steering actuator or motor has stopped working, so Squyres identified that as the possible culprit behind the whole mystery. Each wheel has its own actuator; the jam in the one wheel prevents it from turning left or right.

As the rover did a turn in place on the bedrock, the faulty wheel may have shot out the rock something like your car’s wheels blasting ice chunks out when you gun the engine to get out of a snow drift.

View of “Greeley Haven” on the rim of Endeavour Crater taken by Opportunity. It was assembled from 817 component images taken between Dec. 21, 2011, and May 8, 2012. Click to enlarge. Credit: NASA/ JPL-Caltech

Still, no one knows for sure how it got there. A pal of mine suggested a blast of Martian wind. We’re lucky Opportunity found the intruder. The rover’s been parked at the same spot for weeks as it waits for better weather and a higher sun to help power it along its way. Sticking around the same spot allowed for nearly identical images to be taken on widely-separated Sols. Maybe a closer study of the rock in the coming days will tell us more about how it got there.

Despite being designed for a 90-day mission, the robot-that-could is still kicking 10 years later with more than 23 miles on its odometer. To check out the high resolution, raw images yourself, here are the links: Sol 3528 and Sol 3540.

A snooze recalls the heyday of Martian volcanoes

A wonderful Mars-scape of collapsed lava tubes along the flank of the volcano Ascraeus Mons photographed by the THEMIS camera on the Mars Odyssey satellite in orbit about Mars. Click to photos to enlarge. What appears to be craters are sinkholes in the roofs of other tubes. Credit: NASA/JPL/ASU

I collapsed in the chair yesterday night after a long day. My wife and daughter watched and chuckled from the couch as I nodded off. My submission to sleep was a quiet event marked only by the occasional snore, but the catastrophic rumble-tumble of rock when the roofs of lava tubes on the flanks of Mars’ second highest volcano collapsed must have shaken the ground like an earth, er, marsquake. In my personal situation, the body gave in; on Mars, the roof over former lava conduits within the volcano collapsed under their own weight after the lava drained away from beneath. This happened long ago, during the heyday of Martian volcanism, when lava welled up from multiple locations within the crust to create a whole field of volcanoes, including what would become the picturesque lava tubes of Ascraeus (as-KREE-es) Mons.

Ascraeus Mons is enormous, measuring 300 miles across with a summit caldera 11 miles high. Collapsed lava tubes are visible at upper left and lower right. Credit: NASA/JPL-Caltech/Univ. of Arizona

Like many of Mars’ volcanoes, this one is very similar to the Hawaiian shield volcanoes, where very fluid lavas erupt nearly continuously from one or more vents. The lava flows spread out layer after layer in large sheets across great distances, making shield volcanoes the largest both on Earth and Mars.

The Hawaiian volcanoes are produced by magmas erupting from a “hot spot” in the Earth’s crust. Given the enormous size of the Martian volcanoes and the fact that Mars doesn’t have moving crustal plates, they probably formed the very same way – stewing over hot spots in the Martian crust.

The Opportunity rover was photographed at the rim of Santa Maria crater on New Year's Eve. The crater is 295 feet across and surrounded by blocks of material ejected during impact. Credit: NASA/JPL-Caltech/Univ. of Arizona

The lava tube photo is a recent release from NASA as is the latest image of the Mars Opportunity Rover parked next to Santa Maria crater on New Year’s Eve, which was taken by the Mars Reconnaissance Orbiter. Opportunity will spend about two months investigating the layering of rocks within the crater before moving on to the larger Endeavour crater four miles away. Studies by orbiting spacecraft indicate that Endeavour’s rim contains clay-bearing minerals indicating it was once wet there. The exploration of Mars has always been about ‘finding the water’ with the hopes of finding life, making the crater an ideal location for study.

On January 25, the feisty rover celebrates its 7th year on the planet – amazing for a machine that was designed to last just three months.

The UK (top) and France from Earth orbit. Paris is the bright spot near center with London to the left. Fog covers part of western England and the aurora borealis fringes the planet's edge at top. Credit: NASA / Douglas Wheelock

I can’t resist one last image, taken by space station astronaut Douglas Wheelock last November 8. To see more of Wheelock’s wonderful pix, click HERE.