Curiosity 8/4/12

 
 
NEWS SPECIAL – Mars Science Lab is a “Curiosity”
 

Mars Science Lab mission began with Nov 23, 2011 launch atop ULA Atlas 5 from Cape Canaveral
 

Curiosity (right) dwarfs its predecessors - Mars Exploration Rover (left) & Mars Pathfinder (front)
 
NASA TV:
 
Saturday
·      11:30 am Central (12:30 EDT) – MSL/Curiosity status & entry, descent & landing overview
 
Sunday
·      11:30 am Central (12:30 EDT) – MSL/Curiosity pre-landing news conf & rover comm overview
·      5 pm Central (6 EDT) –  NASA Science News Conference
·      10 pm Central (11 EDT) –  p.m. - MSL/Curiosity landing coverage (Commentary at 10:30 CDT)
 
Monday
·      1:15 am Central (2:15 EDT) – MSL/Curiosity Post-Landing News Conference (no earlier than)
·      2:30 am Central (3:30 EDT) – MSL/Curiosity Rover Landing Coverage &d Commentary
(First Post-Landing Communication Session/Odyssey Downlink)
·      5 am Central (6 EDT) – Live Satellite Post Landing Interviews on the MSL/Curiosity Mission
·      11 am Central (Noon EDT) – MSL/Curiosity post-landing Briefing - Recap & Sol 1 Outlook
·      6 pm Central (7 EDT) – MSL/Curiosity post-landing Briefing - Sol 1 Mid-Day Update
 
HEADLINES AND LEADS
 
Mars Science Lab poised for trail-blazing mission
 
William Harwood - CBS News
 
In a $2.5 billion gamble, a nuclear-powered Mars rover the size of a small car will attempt a pinpoint landing near the base of a 3-mile-high mountain overnight Sunday to search for the building blocks of life and evidence of past or present habitability. In so doing, the Mars Science Laboratory rover, dubbed "Curiosity" in a student naming contest, will climb layer by layer through vast eras of the red planet's enigmatic history, possibly shedding light on the transition from a warmer, wetter past to the drier, frigid world of more modern epochs. Doug McCuistion, director of Mars exploration at NASA Headquarters in Washington, said the mission "could arguably be the most important event in the history of planetary exploration."
 
NASA to athletic Mars rover: 'Stick the landing'
 
Alicia Chang - Associated Press
 
It's NASA's most ambitious and expensive Mars mission yet — and it begins with the red planet arrival late Sunday of the smartest interplanetary rover ever built. Also the most athletic. Like an Olympic gymnast, it needs to "stick the landing." It won't be easy. The complicated touchdown NASA designed for the Curiosity rover is so risky it's been described as "seven minutes of terror" — the time it takes to go from 13,000 mph to a complete stop.
 
With Mars mission and rover Curiosity, NASA hunts building blocks of life
 
Marc Kaufman - Washington Post
 
The last time the United States landed a mission on Mars to look for extraterrestrial life or its building blocks, Gerald Ford was president and the nation had just finished celebrating its 1976 bicentennial. Next week, the long-delayed second attempt will try to deposit a rover on the planet’s surface. The descent and landing in the early hours of Aug. 6 will be the most complex and hair-raising in planetary history. The destination is a deep crater with a three-mile-tall mountain that NASA could only dream about using as a landing site until very recently.
 
A Drop-In Looking for Signs of Company
 
Kenneth Chang - New York Times
 
Right now, a spacecraft containing Curiosity — a car-size, nuclear-powered planet rover — is coasting at 8,000 miles per hour toward Mars, nearing the end of a journey that began in November. With tightening budgets, it is the last big hurrah for NASA’s planetary program for quite a few years. Packed with ingenious new instruments, the rover promises to provide the best-ever examination of the Red Planet, digging up clues to a profound question: Could there ever have been life there? Over the coming week, the pull of gravity will accelerate the spacecraft to 13,000 miles per hour, and early Monday morning Eastern Daylight Time, it is scheduled to execute a series of astoundingly complicated maneuvers and place the rover on the surface. Its new home will be the Gale Crater, just south of the equator, a 96-mile-wide bowl punched out by a meteor more than 3.5 billion years ago. It is one of the lowest places on Mars, which should help advance Curiosity’s $2.5 billion mission: studying the environment of early Mars.
 
NASA hopes are riding on Mars rover's tricky descent
 
Eric Berger - Houston Chronicle
 
It is the last 78 miles of a NASA rover's 154 million-mile journey to Mars that concerns Ravi Prakash the most. That's because this is the first time that NASA - or anyone else - has ever tried to land something nearly so big as the 1-ton Curiosity rover on Mars, and because so much is riding on this particular mission. "We've got to go from five times as fast as a speeding bullet - 13,000 mph - all the way to a screeching halt in seven minutes," said Prakash, a Texas City native who now works at NASA's Jet Propulsion Laboratory on the rover's lander team.
 
Curiosity relies on untried 'sky crane' for Mars descent
 
William Harwood - CBS News
 
The question is straight forward: how to get a car-size rover safely to the surface of Mars? And not just anywhere, but to a very precisely defined bullseye on the floor of a broad crater and within roving distance of a three-mile-high mountain. Traditional landing craft have either bounced to the surface cocooned in giant airbags or made the trip atop a rocket-powered descent stage. But neither approach was an option for NASA's Curiosity rover, the centerpiece of the $2.5 billion Mars Science Laboratory mission. Tipping the scales at one ton, the nuclear-powered Curiosity, a rolling laboratory equipped with a suite of state-of-the-art cameras and instruments, is  too massive to use airbags like the ones that cushioned the landings of NASA's much smaller Pathfinder and the hugely successful Spirit and Opportunity rovers.
 
Relay sats provide ringside seat for Mars landing
 
William Harwood - CBS News
 
To help scientists and engineers follow the action 154 million miles away, the trajectory of the Mars Science Laboratory was set up to make sure the rover's descent to the surface of the red planet occurs within view of three orbiting satellites. NASA's Mars Odyssey and the Mars Reconnaissance Orbiter, along with the European Space Agency's Mars Express satellite, will capture telemetry from the Mars Science Laboratory as the spacecraft makes its nail-biting seven-minute plunge to the floor of Gale Crater early Monday U.S. time.
 
Why Mars again? A look at NASA's latest venture
 
Alicia Chang - Associated Press
 
NASA's new robot rover named Curiosity has spent 8½ months hurtling through space toward its destination Sunday on Mars. It is set to land near the foot of a mountain rising from a giant crater. This marks NASA's 19th mission and eighth landing attempt. The big unknown remains. Scientists want to know if any form of life ever existed there, and that means microscopic organisms. Since the 1960s, spacecraft have zipped past, orbited or landed on Mars in this quest. Two small NASA rovers that arrived in 2004 explored different craters and one is still functioning today.
 
NASA to broadcast Mars Rover Landing from NYC's Times Square Sunday night
 
Space.com
 
NASA's biggest Mars rover landing yet is about to hit Broadway. New Yorkers hoping to see the Aug. 5/6 landing of NASA's huge Mars rover Curiosity alongside like-minded space fans can head to Times Square here on Sunday night (Aug. 5) to catch the rover's touchdown on the Red Planet live on a giant LED television screen. NASA Television's coverage of the agency's $2.5 billion Mars Science Laboratory mission landing will be broadcast live on the Toshiba Vision screen that hangs below the iconic New Year's Eve ball in Times Square, space agency officials say. The broadcast begins at 11:30 p.m. EDT Sunday and runs until 4 a.m. EDT Monday.
 
New York's Times Square to broadcast Mars landing
 
Agence France Presse
 
The highly anticipated landing of NASA's sophisticated $2.5 billion rover on Mars will be broadcast on a large screen in New York City's Times Square, NASA said on Tuesday. The touchdown of the Curiosity rover, equipped with a sophisticated roving toolkit for analyzing the terrain for signs that microbial life once existed, is scheduled for August 6 at 1:31 am Eastern time (0531 GMT).
__________
 
COMPLETE STORIES
 
Mars Science Lab poised for trail-blazing mission
 
William Harwood - CBS News
 
In a $2.5 billion gamble, a nuclear-powered Mars rover the size of a small car will attempt a pinpoint landing near the base of a 3-mile-high mountain overnight Sunday to search for the building blocks of life and evidence of past or present habitability.
 
In so doing, the Mars Science Laboratory rover, dubbed "Curiosity" in a student naming contest, will climb layer by layer through vast eras of the red planet's enigmatic history, possibly shedding light on the transition from a warmer, wetter past to the drier, frigid world of more modern epochs.
 
Doug McCuistion, director of Mars exploration at NASA Headquarters in Washington, said the mission "could arguably be the most important event in the history of planetary exploration."
 
"It truly is a major step forward, both in technology and in potential science return and science capability to unlock the mysteries of Mars in places that have never been accessible to humankind in the past."
 
But getting there will not be easy.
 
The Mars Science Laboratory spacecraft must first endure entry temperatures of up to 3,800 degrees Fahrenheit, crushing deceleration of up to 15 Gs and the 65,000-pound jerk of a huge parachute inflating at supersonic velocity.
 
After slowing the spacecraft to a bit less than 200 mph, the parachute will be cut away and a rocket-powered descent stage, carrying the Curiosity rover bolted to its belly, will fall free for a nail-biting one-mile plunge to the surface.
 
Controlled by the rover's main computer, the descent stage will slow to just 1.7 mph, four of its eight rocket engines will shut down and Curiosity will be lowered on the end of a 25-foot-long tether like a bobber on a fishing line.
 
With the descent stage maintaining its slow fall, the rover's six wheels are expected to touch down on the floor of Gale Crater around 1:17 a.m EDT (GMT-4). Confirmation will be relayed back to Earth in near realtime by NASA's Mars Odyssey satellite.
 
But because of the distance between Earth and Mars -- about 154 million miles -- it will take 13.8 minutes for confirmation of a successful landing to reach anxious engineers and scientists at NASA's Jet Propulsion Laboratory in Pasadena, Calif. That translates into 1:31 a.m. on Aug. 6, Earth-received time.
 
"MSL holds the potential to look for evidence of habitable environments, if they existed, on Mars in the distant past," said NASA science chief John Grunsfeld, a veteran shuttle spacewalker. "The Curiosity rover has the potential to discover the building blocks of life on Mars, if life ever existed on Mars.
 
"However, the Curiosity landing is the hardest NASA robotic mission ever attempted in the history of exploration of Mars or any of our robotic exploration. This is risky business."
 
Curiosity's novel "sky crane" landing technique has dominated news coverage, in part because it seems so outlandish compared to past missions and because it appears riskier given a full-up, end-to-end test was not possible in Earth's atmosphere and gravity.
 
But engineers are confident the entry, descent and landing system will work as advertised, the first act in the most complex, expensive and scientifically significant robotic Mars mission ever attempted.
 
"This rover, the Curiosity rover, is really a rover on steroids," Colleen Hartman, a senior NASA manager, said before launch. "It's an order of magnitude more capable than anything we have ever launched to any planet in the solar system. It will go longer, it will discover more than we can possibly imagine."
 
Over the course of a planned two-year mission, Curiosity will act as a robotic geologist, using high definition cameras to photograph its surroundings in exquisite detail, beaming back wide-angle high-resolution panoramas as well as close-up microscopic views through what amounts to a geologist's hand lens.
 
Equipped with 10 state-of-the-art instruments and a sophisticated robot arm, the rover will drill into rocks and soil, use a rock-vaporizing laser to assess more distant targets and collect rock and soil samples for detailed chemical analysis.
 
The initial phases of the mission will be focused on the crater floor and an alluvial fan visible from orbit where scientists believe water may have pooled in the distant past.
 
But the long-range objective is Aeolis Mons, dubbed Mount Sharp by NASA, a huge wind-eroded mound of sedimentary rocks in the center of Gale Crater that rises more than three miles, higher than Mt. Rainier above Seattle.
 
The instruments aboard Curiosity were not designed to look for signs of life. Rather, the primary goal of the Mars Science Laboratory is to search for carbon compounds and evidence of past or present habitability.
 
"We are not a life detection mission," Grotzinger said. "The first and important step toward that is to try to understand where the good stuff may be."
 
Grotzinger would not give odds on finding carbon compounds in Gale Crater, but "the information from orbit looks so darn good ... I'd be surprised if we landed on the surface and didn't find something that looked like it could have been a formerly habitable environment.
 
"But if you're trying to get me to say what are the chances of finding organic carbon, I'd say it's like looking for a needle in a haystack, and the haystack is as big as a football field."
 
Searching for carbon compounds is only part of Curiosity's mandate. As it works its way up the 15-degree slopes of Mount Sharp and passes from older to younger layers, the rover is expected to cross over beds marking a geologically sudden transition from a warmer, wetter past to a drier, less hospitable age.
 
In so doing, hundreds of thousands to tens of millions of years of the planet's evolution will be brought into focus.
 
"The really cool thing about the Gale stratigraphic succession to me is it's a tour through nearly the entire history of Mars where we can begin to understand these major changes in the environmental history of the planet," Grotzinger said in a more recent interview. "And I can't think of another place on Mars where you can go do that."
 
To get a sense of the landing site's potential, Grotzinger said the layers making up Mount Sharp are three times thicker than those in the Grand Canyon, which "takes you ... through 300 million years of Earth history, from the origin of animals to the origin of dinosaurs."
 
"If you were to have remote sensing data from an orbiter around Earth, looking at Earth and the Grand Canyon 150 years ago, nobody would have ever predicted that that's what you would discover if you went there one day," Grotzinger said. "I don't know what it is that we're going to discover about Mars. But I have to believe it's going to be something really good."
 
The high-stakes mission comes at a critical time for NASA's planetary exploration program as budget pressures threaten to sharply reduce the scope of the agency's robotic missions.
 
The Obama administration's fiscal 2013 budget request calls for $17.7 billion for NASA, but it cuts $300 million from planetary science, most of it from the Mars program.
 
As a result, NASA has backed out of a 2008 agreement with the European Space Agency to share the costs of two ambitious Mars missions known as ExoMars, which called for launch of an orbiter in 2016 and two rovers in 2018.
 
Along with searching for signs of past or present life on Mars, the missions also would have tested technologies needed for a long-sought sample return mission.
 
"Tough choices had to be made," NASA Administrator Charlie Bolden said when the budget was unveiled earlier this year. "This means we will not be moving forward with the planned 2016 and 2018 ExoMars mission. ... Instead, we'll develop an integrated strategy to ensure the next steps in Mars exploration will support science as well as human exploration goals and potentially take advantage of the 2018 and 2020 exploration windows."
 
In the wake of the budget's release, Bill Nye, chairman of the Planetary Society, said the "priorities reflected in this budget would take us down the wrong path."
 
"Science is the part of NASA that's actually conducting interesting and scientifically important missions," he said in a statement. "Spacecraft sent to Mars, Saturn, Mercury, the Moon, comets and asteroids have been making incredible discoveries, with more to come from recent launches to Jupiter, the Moon and Mars. The country needs more of these robotic space exploration missions, not less."
 
In a rare show of bipartisan agreement, Rep. Adam Schiff, D-Calif., and John Culberson, R-Texas, whose states include NASA field centers, wrote in Space News that without congressional action, "the administration's cuts to planetary science would devastate America's planetary program."
 
"The robotic Mars program, one of our nation’s science jewels, faces the most severe cuts, including a rover mission to Mars in 2018 identified as the highest priority in planetary science in the most recent decadal survey," they wrote. "This would be a tragic loss for a program that has made major scientific discoveries and captured the interest of people around the world."
 
The Curiosity rover is the only so-called "flagship" mission currently in the Mars pipeline and it takes years to plan, design and build new spacecraft. Aerospace engineer Robert Zubrin, president of the Mars Society and author of "The Case for Mars," said in an interview that the fate of NASA's Mars program rests firmly on Curiosity's shoulders.
 
"This is a superb mission, if it succeeds," he said. "On the other hand, if it fails, it's the flagship out the window. That would be serious enough. But the stakes were upped this past February when the Obama administration canceled the 2016 and 2018 missions, and thus completely scrambled the program, completely set it adrift."
 
If Curiosity fails, he said, "not only do you lose this mission, but I think we lose the rest of the decade. On the other hand, if this succeeds, it will be a brilliant mission, it will be the best Mars mission ever flown and I think we have a real chance of not only reversing the missions that were cut but moving on towards sample return."
 
MSL Project Manager Pete Theisinger said in an interview that he was aware of the outside scrutiny and pressure to chalk up a success. But he said the MSL team was not distracted.
 
"Down in the trenches where the work's actually accomplished, people love what they do, they're very professional about it and they want to do the right job and so that's all they think about," he said. "It wouldn't matter whether it was this two-and-a-half-billion-dollar thing that's on the national stage or it was a $100,000 thing in the lab. They feel the same.
 
"When you get up to the top of the food chain, yeah, there's a feeling that this is a very visible mission, we know that, people like you don't call me if it's not a very visible mission. And so, we know that. But once again, the job is to get the job done and to do it in the best balanced, prudent approach that we can. I don't think we feel it, we just know it's there."
 
Launch originally was planned for 2009, but in 2008, the flight was delayed two years to verify the integrity of the myriad actuators used in the rover's mobility system and robot arm, a delay that added $400 million to the project's price tag.
 
Curiosity's journey finally got underway on Nov. 26, 2011, when a United Launch Alliance Atlas 5 rocket boosted the craft into space. The spacecraft has performed in near flawless fashion during the long cruise to Mars and now the stage is set for entry, descent and landing Aug. 6.
 
Acting as a robotic geologist, Curiosity is well suited for its trailblazing mission, dwarfing the hugely successful Spirit and Opportunity rovers both in size and scientific capability. The instruments carried by each of the earlier rovers weighed about 11 pounds. The 10 aboard Curiosity weigh 165 pounds.
 
Not counting its robot arm, Curiosity is 10 feet long, nine feet wide and seven feet high measured to the top of its main camera mast. Its mobility system is similar in design to that used by Spirit and Opportunity, but its six 20-inch-wide wheels are twice the size of the earlier models. Each wheel has its own drive motor and the four corner wheels are independently steerable.
 
Top speed is over hard, flat ground is about a tenth of a foot per second, although the rover typically will move at half that velocity when operating autonomously and using hazard avoidance.
 
The earlier rovers were solar powered, forcing them to shut down at night and to hibernate in winter months to conserve power and heat. MSL is powered by a radioisotope thermoelectric generator, using the heat produced by the decay of radioactive plutonium dioxide to generate electricity. Excess heat is used to keep electronics and other sensitive systems from getting too cold.
 
Curiosity is equipped with redundant computers, using one at a time and keeping the other as a backup. The computers feature radiation-resistant PowerPC 750 processors operating at 200 megahertz with two gigabytes of flash memory storage, about eight times more than Spirit and Opportunity.
 
The system was designed from the ground up to use the orbiting Odyssey and Mars Reconnaissance Orbiter satellites to relay engineering and scientific data back to Earth.
 
Independent of the weather and the sun, Curiosity is designed to operate for at least one martian year -- two Earth years -- and to rove at least 12 miles. But engineers expect it to continue operating well beyond its design specification, both in time and distance.
 
"You're asking a project manager how long it's supposed to live and you expect an answer?" Theisinger laughed. "We test these things, the mechanical or moving parts, we test for either two or three times life, usually three times life. So if we know a wheel is supposed to run for 20 kilometers, we'll test it to 60 kilometers.
 
"We don't test them to failure. All that we know is that we've tested the mechanisms for two or three times life and they all passed that test program. The RTG is good for a decade, 12 years, 15 years, something like that, before we really get into power issues. The battery is probably good for eight years. The electronics are high reliability electronics, but some of it is single string.
 
"It could last a long time if we haven't made a mistake," he said. "If Mars doesn't get us, it could last a long time."
 
The heart of the spacecraft is the most sophisticated instrument package ever sent to Mars.
 
The Sample Analysis at Mars, or SAM, instruments will be used to analyze soil and rock fragments delivered by the lander's robot arm. It includes a gas chromatograph, a mass spectrometer and a laser spectrometer to look for carbon compounds and measure isotope ratios, which will shed light on the history and distribution of water and the evolution of the martian atmosphere.
 
"You've got to have water for life as we know it," Grotzinger told CNET in an earlier interview. "The second thing is you need a source of energy. ... And then the important thing is, you need the fundamental building block, which is carbon."
 
Whether or not life originated on Mars "verges more on philosophy, really," he said. "We don't know how life originated on Earth. I'm really focused on the question, not if life evolved, but if it did evolve where would it be preserved? And where are the places we need to go to find the best potential records of things that could be clues that would lead us on future missions toward the discovery of biosignatures?"
 
Another instrument, called CheMin, uses X-ray diffraction to identify the minerals in collected rocks and soils. The Mars Hands Lens Imager, mounted on the robot arm, will take close-up photos of selected samples while the Alpha Particle X-ray Spectrometer, also on the arm, measures the abundances of various elements.
 
A camera mounted on a mast atop the rover will take high-resolution stereo pictures as well as high-definition video. Another mast-mounted instrument known as ChemCam will use a laser to vaporize the surface layers of nearby rocks, a spectrometer to measure the types of materials present in the debris and a camera to photograph the site.
 
A Radiation Assessment Detector will will characterize the radiation environment at the surface, a key factor in planning for eventual crewed missions, while a suite of Spanish instruments called the Rover Environmental Monitoring Station monitors the martian weather.
 
An instrument provided by Russia, the Dynamic Albedo of Neutrons experiment, will look for signs of water or ice below the surface.
 
"We've got this feeling now of Mars as a much more dynamic planet," Grotzinger said. "The thing about this mission is, it's really going to confront the whole problem of the origin of sedimentary rocks on Mars and what they mean. Sedimentary rocks on Earth, they are the overwhelming storehouse of organic materials in the history of life. If you want to explore for those organic materials, you've got to know how these damn rocks formed."
 
Climbing Mount Sharp may help answer that question, and undoubtedly raise many more, including what to do next.
 
"There are two major decision points for the science team in this mission," Grotzinger said. "We've done one, which was to pick Gale over the other three landing sites. ... The second big decision is going to be when we get up to a boundary (on Mount Sharp) where you can see that the hydrated minerals go away.
 
"There are some people who are going to want to go to the top. And there are other people who are going to say, why don't we just go across that boundary and do a bunch of work on the other side, maybe spend a year doing that, and then let's go down again and work on the wet kind of rock types that we saw on the way up.
 
"I think the team will divide into two groups on that one. That will be a major decision."
 
NASA to athletic Mars rover: 'Stick the landing'
 
Alicia Chang - Associated Press
 
It's NASA's most ambitious and expensive Mars mission yet — and it begins with the red planet arrival late Sunday of the smartest interplanetary rover ever built. Also the most athletic.
 
Like an Olympic gymnast, it needs to "stick the landing."
 
It won't be easy. The complicated touchdown NASA designed for the Curiosity rover is so risky it's been described as "seven minutes of terror" — the time it takes to go from 13,000 mph to a complete stop.
 
Scientists and engineers will be waiting anxiously 154 million miles away as the spacecraft plunges through Mars' thin atmosphere, and in a new twist, attempts to slowly lower the rover to the bottom of a crater with cables.
 
By the time Earthlings receive first word of its fate, it will have planted six wheels on the ground — or tumbled itself into a metal graveyard.
 
If it succeeds, a video camera aboard the rover will have captured the most dramatic minutes for the first filming of a landing on another planet.
 
"It would be a major technological step forward if it works. It's a big gamble," said American University space policy analyst Howard McCurdy.
 
The future direction of Mars exploration is hanging on the outcome of this $2.5 billion science project to determine whether the environment was once suitable for microbes to live. Previous missions have found ice and signs that water once flowed. Curiosity will drill into rocks and soil in search of carbon and other elements.
 
Named for the Roman god of war, Mars is unforgiving with a hostile history of swallowing man-made spacecraft. It's tough to fly there and even tougher to touch down. More than half of humanity's attempts to land on Mars have ended in disaster. Only the U.S. has tasted success, but there's no guarantee this time.
 
"You've done everything that you can think of to ensure mission success, but Mars can still throw you a curve," said former NASA Mars czar Scott Hubbard who now teaches at Stanford University.
 
The Mini Cooper-sized spacecraft traveled 8½ months to reach Mars. In a sort of celestial acrobatics, Curiosity will twist, turn and perform other maneuvers throughout the seven-minute thrill ride to the surface.
 
Why is NASA attempting such a daredevil move? It had little choice. Earlier spacecraft dropped to the Martian surface like a rock, swaddled in airbags, and bounced to a stop. Such was the case with the much smaller and lighter rovers Spirit and Opportunity in 2004.
 
At nearly 2,000 pounds, Curiosity is too heavy, so engineers had to come up with a new way to land. Friction from the thin atmosphere isn't enough to slow down the spacecraft without some help.
 
During its fiery plunge, Curiosity will brake by executing a series of S-curves — similar to how the space shuttle re-entered Earth's atmosphere. At 900 mph, it will unfurl its huge parachute. It then will shed the heat shield that took the brunt of the atmospheric friction and switch on its ground-sensing radar.
 
A mile from the surface, Curiosity will jettison the parachute and fire up its rocket-powered backpack to slow it down until it hovers. Cables will unspool from the backpack and slowly lower the rover — at less than 2 mph. The cables keep the rocket engines from getting too close and kicking up dust.
 
Once the rover senses touchdown, the cords will be cut.
 
Even if the intricate choreography goes according to script, a freak dust storm, sudden gust of wind or other problem can mar the landing.
 
"The degree of difficulty is above a 10," said Adam Steltzner, an engineer at NASA's Jet Propulsion Laboratory, which manages the mission.
 
It takes 14 minutes for radio signals on Mars to travel to Earth. The lag means Curiosity will already be alive or dead by the time mission control finds out.
 
The rover's landing target is Gale Crater near the Martian equator. It's an ancient depression about the size of Connecticut and Rhode Island combined with a 3-mile-high mountain rising from the center of the crater floor.
 
Scientists know Gale was once waterlogged. Images from space reveal mineral signatures of clays and sulfate salts, which form in the presence of water, in older layers near the bottom of the mountain.
 
During its two-year exploration, the plutonium-powered Curiosity will climb the lower mountain flanks to probe the deposits. As sophisticated as the rover is, it cannot search for life. Instead, it carries a toolbox including a power drill, rock-zapping laser and mobile chemistry lab to sniff for organic compounds, considered the chemical building blocks of life. It also has cameras to take panoramic photos.
 
Humans have been mesmerized by the fourth rock from the sun since the 19th century when American astronomer Percival Lowell, peering through a telescope, theorized that intelligent beings carved what looked like irrigation canals. Scientists now think that if life existed on Mars — a big if — it would be in the form of microbes.
 
Curiosity will explore whether the crater ever had the right environment for microorganisms to take hold.
 
Even before landing, it got busy taking radiation readings in space during its 352-million-mile cruise — information that should help its handlers back home determine the radiation risk to astronauts who eventually travel to the red planet.
 
Curiosity's journey has been fraught with bumps. Since NASA had never built such a complicated machine before, work took longer than expected and costs soared. Curiosity was supposed to launch in 2009 and land in 2010, but the mission — already $1 billion over budget — was pushed back two years.
 
The delay created a cascade. Burdened with budget woes, NASA reneged on a partnership with the European Space Agency to land a drill-toting spacecraft in 2018. The space agency is in the midst of revamping its Mars exploration program that will hinge heavily on whether Curiosity succeeds.
 
The extra time allowed engineers to test and re-test the rover and all its parts, taking a spacecraft stunt double to the Mojave Desert as if it were Mars. For the past several months, engineers held dress rehearsals at the sprawling JPL campus 10 miles northeast of downtown Los Angeles in anticipation of landing day when they will carry on a decades-old tradition of passing out "good luck" peanuts.
 
Practice is over. It's show time. To Mars or bust.
 
With Mars mission and rover Curiosity, NASA hunts building blocks of life
 
Marc Kaufman - Washington Post
 
The last time the United States landed a mission on Mars to look for extraterrestrial life or its building blocks, Gerald Ford was president and the nation had just finished celebrating its 1976 bicentennial.
 
Next week, the long-delayed second attempt will try to deposit a rover on the planet’s surface.
 
The descent and landing in the early hours of Aug. 6 will be the most complex and hair-raising in planetary history. The destination is a deep crater with a three-mile-tall mountain that NASA could only dream about using as a landing site until very recently.
 
It’s the most ambitious, the most costly ($2.5 billion) and the most high-stakes mission ever to another planet. It was also described last week by the agency’s top scientist, former astronaut John M. Grunsfeld, as “the most important NASA mission of the decade.”
 
“There is no doubt that this is a risky mission, and that is coming from a human-spacecraft guy,” Grunsfeld said. “It’s hard to get something this big and complex to the surface of Mars, and then to get it to start roving. Thousands of people around the world working on it will be feeling their lives are riding on the mission landing successfully. We’ll all know soon if the risk was worth it.”
 
What the Mars Science Laboratory mission and its rover named Curiosity bring to Mars is a capacity to analyze the planet with much more sophistication than before, and to do it over a sizable and scientifically rich expanse.
 
The goal is not to find Martian life per se but rather to ferret out carbon-based organic compounds that are building blocks of life, and then to determine whether the Gale Crater landing site was ever suitable for creatures. Both are integral parts of the science of astrobiology — the search for life beyond Earth.
 
A fully loaded SUV
 
At 10 feet long and seven feet high at the top of its camera mast, Curiosity is the size of an SUV and weighs almost a ton, about three times more than the Spirit and Opportunity rovers sent to Mars in 2003 on a primarily geological mission. Its robotic arm for digging soil and drilling rock is seven feet long, almost three times longer than previous rover arms. This tool will provide more and better samples for the lab’s instruments, which will do their analysis on Mars and send back the results to scientists here.
 
Curiosity will have numerous ovens to bake soil and rocks up to 1,800 degrees and analyze what comes out; it will have a laser zapper to free up potentially important targets in rocks; it will have cameras with unprecedented capabilities, including one that will take video of the last several minutes of the high-drama landing, now dubbed “seven minutes of terror” by NASA.
 
Getting to Mars, and especially landing on it, is difficult. Forty-four missions — flybys, orbits and landings — have been sent to the planet by NASA, the former Soviet Union, Russia, the European Space Agency, Japan and China, and about one-third have made it. All six successful landings were flown by NASA. (A Soviet capsule made a soft landing in 1971 but then sent back only 14 seconds of data, so it is not considered to have succeeded.)
 
Curiosity’s descent — after a voyage that began last Nov. 25 and covered 354 million miles — will be particularly stressful because the weight of the spacecraft required a new landing technique. The capsule containing Curiosity will enter the atmosphere at 13,200 mph and have less than seven minutes to slow down enough to drop the rover gently onto the surface of the planet.
 
Much of the technology is new or being used in a novel way and, while the component parts have been tested and retested, the landing as a complete sequence has never been tried. “Actually, the landing will be our first test that the systems can work,” said the project’s chief engineer, Robert Manning.
 
But the risk goes beyond the difficulty of the landing and the complexity of Curiosity’s 10 major instruments. That’s because Curiosity will land just as Congress and the administration debate a plan to slash NASA’s Mars and planetary programs significantly. NASA officials and Mars aficionados hope the rover will make discoveries that will limit the cuts, while knowing that a crash landing or failed instruments could further curtail the programs.
 
“I think a major discovery by Curiosity, such as finding the building blocks of life or any other indication of life, would certainly lead us to reconsider our science approach at Mars,” said James Green, director of NASA’s Planetary Sciences Division. “Why? Because if there is, or was, life on Mars, then we’d have to assume life is everywhere in the galaxies. We would have to rethink our place in the universe.”
 
‘Our place in the universe’
 
One reason that NASA has not sent a life-detecting mission to Mars in so long is that the first one came back with very disappointing results. The twin Viking landers touched down in 1976 with great anticipation that not only the building blocks of life but also life itself would probably be found.
 
Instead, the Viking mission found a cold, desert planet that came to be seen as virtually incapable of supporting life. While one life-detection experiment using nutrients brought to Mars and tagged with radioactive carbon did show positive results several times, NASA officials and other scientists concluded that those findings were most likely in error. More disheartening, the instrument designed to identify organic molecules came back with a finding of “no organics.” Without organics, virtually all scientists say, there can be no life.
 
But in the past decade, NASA scientists and others have produced evidence that the planet was once much warmer and wetter. They know, for instance, that the Gale Crater site was once covered in water, and they know that it has minerals and clays that can be formed only in the presence of water.
 
In addition, NASA astrobiologist Michael Mumma reported in 2009 finding plumes of methane gas erupting at specific spots and at predictable times on Mars. More than 90 percent of methane on Earth is formed as a byproduct of biology, from cows’ digestive systems and rotting trees to the life cycle of tiny microbes. It remains unknown whether some of the methane on Mars also comes from biological sources.
 
And finally, a paper in May from Andrew Steele of the Carnegie Institution of Washington identified organic material in meteorites known to have fallen to Earth from Mars. An expert in the contamination of rocks that fall to Earth from space, Steele concluded that some of the organic material he found was clearly not from Earth, and so it either came from Mars or was picked up by the meteorite as it flew through space.
 
Climbing the mountain
 
Combining the promising new science about Mars with the capabilities of Curiosity, NASA science chief Grunsfeld said he considers it likely that organic materials will be found this time. Gale Crater is a much more promising site than the plains where the Viking landers did their work, and Curiosity has more than 35 years of improved technology and know-how.
 
The rover will also be the first to approach, analyze and then partially climb a Martian mountain. The layered outcrops of what has been named Mount Sharp will provide a geological history of the crater and perhaps the planet, and so are an integral part of the Curiosity mission.
 
Geologists will be looking at those layers to determine when water was present in the crater, whether it moved like a river or was like a lake, what elements and compounds were in the soil and air, and even what temperatures and other atmospheric conditions existed. The lead scientist for the rover is John Grotzinger of the California Institute of Technology, and he is a geologist.
 
“We have never had an opportunity even close to this on Mars before,” he said, referring to the exposed and “readable” cliffs of Mount Sharp. “We’re just waiting with bated breath.”
 
An additional Curiosity goal is to learn more about how to protect astronauts who may someday fly to Mars. The landing of a large vehicle is part of that learning curve, but so too is Curiosity’s radiation assessment detector, a toaster-size instrument that will measure and identify high-energy and potentially harmful radiation on the Martian surface, such as protons, energetic variations of common elements, neutrons and gamma rays.
 
The Curiosity mission is scheduled to last for another two years, but it could continue much longer if funding becomes available. The rover’s power source is a nuclear battery that, if all goes according to plan, could move the rover and keep it warm for years longer.
 
There is precedent for prolonged rover missions: The Spirit and Opportunity rovers were designed to operate on Mars for 13 weeks, but Spirit sent back information until 2009, and Opportunity is still traveling. So if the landing succeeds and the rover and instruments work as planned, Curiosity might be telling us about Mars for years to come.
 
A Drop-In Looking for Signs of Company
 
Kenneth Chang - New York Times
 
Right now, a spacecraft containing Curiosity — a car-size, nuclear-powered planet rover — is coasting at 8,000 miles per hour toward Mars, nearing the end of a journey that began in November. With tightening budgets, it is the last big hurrah for NASA’s planetary program for quite a few years. Packed with ingenious new instruments, the rover promises to provide the best-ever examination of the Red Planet, digging up clues to a profound question: Could there ever have been life there?
 
Over the coming week, the pull of gravity will accelerate the spacecraft to 13,000 miles per hour, and early Monday morning Eastern Daylight Time, it is scheduled to execute a series of astoundingly complicated maneuvers and place the rover on the surface. Its new home will be the Gale Crater, just south of the equator, a 96-mile-wide bowl punched out by a meteor more than 3.5 billion years ago. It is one of the lowest places on Mars, which should help advance Curiosity’s $2.5 billion mission: studying the environment of early Mars.
 
“Water flows downhill, and that’s where we’re going,” John P. Grotzinger, a professor of geology at the California Institute of Technology who serves as the mission’s project scientist, said during a news conference this month.
 
Bits of the Martian past may lie in the rocks at the bottom of the crater. Over the past decade, NASA’s robotic spacecraft have turned up convincing evidence that eons ago the planet held one of the prerequisites for life. Water flowed on Mars, at least on occasion.
 
Life’s other prerequisites are carbon-based molecules and energy. Sunshine or volcanic heat could have provided the necessary energy. With Curiosity, the search is on for the carbon-based molecules.
 
“I think this is the Hubble Space Telescope of Mars exploration,” said John M. Grunsfeld, NASA’s associate administrator in charge of the science mission directorate. (He is best known as the Hubble repairman, flying on three space shuttle missions to refurbish and upgrade the telescope.) “This is the first time that we have a real analytical laboratory heading to the surface.”
 
But before Curiosity can make any discoveries, it has to land.
 
In the control room at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., it will still be Sunday evening when the nervous wait begins. First will come word that the spacecraft containing Curiosity has entered the Martian atmosphere. Just seven minutes later, the spacecraft must flawlessly execute a series of complex maneuvers to land the rover on the surface.
 
If all goes as planned, the friction of Mars’ thin air rushing past the heat shield will have slowed the spacecraft to 1,000 miles per hour. A 51-foot-wide parachute will pop out, generating up to 65,000 pounds of drag force. Then the heat shield will pop off so that the radar can find the landing site in Gale Crater.
 
Even with the parachute drag, the spacecraft will be barreling toward the surface at 200 miles per hour. Next it will cut away the parachute and ignite its descent engines to slow down further.
 
The last three NASA rovers — Sojourner in 1997 and Spirit and Opportunity in 2004 — had similar landing systems, except for the final step. For those three, a cocoon of air bags inflated around the rover, which was then dropped the last 50 feet or so, bouncing and rolling until it came to a stop.
 
But Curiosity, about the size of a Mini Cooper, is five times as heavy as Spirit or Opportunity, making air bags impractical. It would be equivalent of trying to cushion a car hitting a brick wall at highway speed without any damage to the car.
 
Instead, Curiosity will be lowered by cable all the way to the ground from the hovering rocket stage in what NASA calls a sky crane maneuver. Once Curiosity bumps into Mars at a gentle 1.7 miles per hour, the cable will be cut, and the rocket stage will fly off to crash about a third of a mile away.
 
“Is it crazy?” Doug McCuistion, director of NASA’s Mars exploration program, asked rhetorically during the news conference. “Well, not so much. Once you get comfortable, once you understand it, it’s not a crazy concept.”
 
The NASA engineers who devised the sky crane maneuver say that after thorough testing of the different parts of the system and numerous computer simulations, they are confident that they have built something that will work.
 
“In the simulated world, we’ve landed on Mars millions of times,” one of the engineers, Steven Lee, said in an interview. “I’m actually very comfortable. I’m more comfortable with the impending landing than I was with the launch.”
 
Still, success is not guaranteed. The Curiosity landing is the “hardest NASA robotic mission ever attempted,” Dr. Grunsfeld said.
 
If it survives, Curiosity will come to rest about 1:17 a.m. Eastern Daylight Time. NASA’s Mars Odyssey orbiter will be passing overhead, in position to relay radio transmissions from Curiosity to Earth. About 14 minutes later, the fate of Curiosity may be known at mission control. (NASA warns that with the vagaries of space communications, a day or two could pass before confirmation of a successful landing reaches Earth.)
 
Engineers and scientists will spend several weeks checking out the condition of the rover. A few photographs will be beamed back the first few days, first in black and white, then in color. One of the first chores will be a software upgrade for Curiosity’s computers. The first drive is most likely more than a week after landing. The first flexing of the rover’s robotic arm would occur after that.
 
“In a couple of months, we’ll be on the road to Mount Sharp,” said Dr. Grotzinger, the project scientist.
 
For reasons no one can quite explain, a three-mile-high mountain, Aeolis Mons, stands at the center of Gale Crater. Informally known as Mount Sharp, in honor of Robert P. Sharp, a pioneering planetary scientist at Caltech, it is taller than any mountain in the continental United States. Orbiting spacecraft have already observed that Mount Sharp consists of layered rocks presumably formed out of sediment that settled at the bottom of Gale over millions of years. Later the sediment was somehow scoured out, leaving Mount Sharp at the center.
 
The layers, scientists believe, will provide a history book about early Mars. Orbiters have spotted at the base of the mountain signs of clays — minerals that form in the presence of water and that point to an environment that was less acidic than present-day Mars. As Curiosity crawls up the mountain, it will roll across younger and younger rocks, and the changes could tell how the environment of Mars changed.
 
For that task, Curiosity is carrying some of the most sophisticated science tools ever devised. A rock-vaporizing laser called ChemCam can turn a smidgen of rock into a puff of glowing, superhot gas from a distance of up to 25 feet. From the colors of light emitted by the gas, ChemCam can identify elements in the rock. A rock full of carbon, for example, would merit a closer look.
 
“It is really designed to be a sentry or advance guard for the rover and identify the most interesting samples,” said Roger C. Wiens, a physicist at Los Alamos National Laboratory who is the instrument’s principal investigator. ChemCam can also vaporize dust on a rock to get a better look at its surface.
 
Other instruments include a weather station; a device that shoots particles into the rock and measures X-rays coming out; and several cameras, including one that mimics the hand lens of a geologist for close-up looks at rocks. The size of a microwave oven, the biggest and probably most ambitious of the instruments is called Sample Analysis at Mars — Sam for short.
 
Sam contains 74 cups for studying ground-up rock. Most samples will be heated to 1,800 degrees, and three different instruments will be used to identify what gases are released, including the possibility of carbon-based molecules known as organics.
 
Confusingly, organic molecules can arise from nonliving chemical reactions, so the presence of organics would not prove the existence of life. Rather, the discovery of such molecules would add to the possibility of life on Mars long ago — or perhaps even today.
 
This will be the first search for organics since NASA’s two Viking landers in 1976. The two Vikings saw no signs of organics, which led to the dispiriting conclusion that there was no possibility of life ever on Mars. (A separate experiment did have results consistent with the existence of microbes in the soil, but most scientists concluded that it was the result of some odd, nonliving chemical reactions.)
 
New research a couple of years ago, however, suggested that the presence in the soil of chemicals known as perchlorates could have destroyed all of the organic molecules as the samples were being heated, thus giving misleading results. The Phoenix Mars lander discovered perchlorates in the Martian soil near the north pole in 2008.
 
Sam’s ovens are hotter than the ones on the Vikings and should destroy the perchlorates before they destroy the organics, said Paul R. Mahaffy, the principal investigator of the Sam instrument. In addition, nine of the cups include a chemical solvent that would allow analysis at lower temperatures.
 
Sam will also analyze the atmosphere, possibly confirming controversial claims that it contains methane. Methane, broken apart by sunlight and chemical reactions, lasts only a few centuries. If there is methane in Mars’s atmosphere, something must be making it — perhaps microbes.
 
The main mission is scheduled to last two years. Then again, the last two rovers, Spirit and Opportunity, were designed for only three months of exploration. Spirit lasted six years, and Opportunity is still rolling.
 
Unlike the earlier rovers, Curiosity is powered by plutonium, generating electricity from the heat of radioactive decay. It is the same type of power supply that the two Voyager spacecraft traveling at the distant reaches of the solar system have been running on for nearly 35 years.
 
If Curiosity lands successfully, it, too, could operate for decades.
 
“I’m on the edge of my seat,” Dr. Grunsfeld said. “I’m not going to sit back until it’s safely on Mars.”
 
NASA hopes are riding on Mars rover's tricky descent
 
Eric Berger - Houston Chronicle
 
It is the last 78 miles of a NASA rover's 154 million-mile journey to Mars that concerns Ravi Prakash the most.
 
That's because this is the first time that NASA - or anyone else - has ever tried to land something nearly so big as the 1-ton Curiosity rover on Mars, and because so much is riding on this particular mission.
 
"We've got to go from five times as fast as a speeding bullet - 13,000 mph - all the way to a screeching halt in seven minutes," said Prakash, a Texas City native who now works at NASA's Jet Propulsion Laboratory on the rover's lander team.
 
Five times the size of the Spirit and Opportunity rovers already on Mars, Curiosity is packed with scientific equipment: HD-resolution cameras that can also capture video; a laser than can ignite a spark on rocks 20 feet away to determine what they're made of; and other high-tech tools including an X-ray diffraction setup, a mass spectrometer, and a gas chromatograph.
 
With these devices the six-wheeled rover will be able to sample hundreds of layers of sedimentary rock, allowing scientists to understand how the surface of Mars changed over time, and providing a detailed history of the Red Planet and clues to whether life could have flourished there.
 
But it's got to get there safely at first.
 
Adding to the pressure is that NASA is not currently planning or building a next generation rover to go to Mars. More than 200 scientists attended a NASA meeting earlier this year in Houston to discuss plans for follow-up missions, but none has been chosen.
 
Nail-biting time
 
So Curiosity, itself a decade in the works, is it for a long time.
 
"With no sense of how or when we will follow this up, and without knowing which direction our tools and techniques are evolving - yes, landing successfully is a big deal," said Mark Lemmon, a Texas A&M University planetary scientist who will help operate the rover on Mars.
 
Launched in November, the $2.5 billion rover will reach the upper limit of the Martian atmosphere at 12:30 a.m. CDT on Aug. 6. Almost out of rocket fuel, it will proceed directly to the planet's surface.
 
Then the nail-biting will begin. The capsule carrying the rover will slow as it falls through the thin Martian atmosphere, and at seven miles above the Red Planet a parachute will deploy. One mile above the surface, and at a speed of 180 mph, the parachute will separate, and thrusters will further slow the descent.
 
'Sky crane' maneuver
 
About 12 seconds before touchdown a completely unprecedented maneuver will occur: as part of a "sky crane" maneuver, cables will lower the rover to the ground at a feathery descent of 1.7 mph. Upon reaching the ground the cables will be cut, and the descent stage will fly away.
 
If all goes well, Curiosity will be ready to roll in the Gale crater, which rests within a deep depression on the surface of Mars.
 
Millions of simulations
 
Given that water flows down hill, the low-lying Gale crater is a place where scientists believe they have a good chance of finding evidence of past water on Mars during one of the planet's wetter epochs.
 
"We are going to the very best place we could find to go to," said John Grotzinger, a California Institute of Technology scientist who is one of the rover project's leaders.
 
But will the technical descent work? Scientists say they're 90 to 95 percent confident the landing will be successful.
 
They've run millions of simulations, tested the parachutes in powerful wind tunnels and performed drop tests on Earth.
 
Nevertheless it's not entirely possible to simulate the real thing, in which the lander will be operating on the basis of its own sensors and software, with the communication lag between Earth and Mars too long for scientists to make adjustments to the landing during the rapid descent.
 
Some of those automated step-by-step procedures will be the same as those used by the Apollo landers in their return to Earth, Prakash said. But there will be no astronauts aboard this time to make adjustments.
 
So the hundreds of scientists on the Mars lander team will be watching from Earth, just like the rest of us.
 
Curiosity relies on untried 'sky crane' for Mars descent
 
William Harwood - CBS News
 
The question is straight forward: how to get a car-size rover safely to the surface of Mars? And not just anywhere, but to a very precisely defined bullseye on the floor of a broad crater and within roving distance of a three-mile-high mountain.
 
Traditional landing craft have either bounced to the surface cocooned in giant airbags or made the trip atop a rocket-powered descent stage. But neither approach was an option for NASA's Curiosity rover, the centerpiece of the $2.5 billion Mars Science Laboratory mission.
 
Tipping the scales at one ton, the nuclear-powered Curiosity, a rolling laboratory equipped with a suite of state-of-the-art cameras and instruments, is  too massive to use airbags like the ones that cushioned the landings of NASA's much smaller Pathfinder and the hugely successful Spirit and Opportunity rovers.
 
While a legged lander could do the trick, powerful braking rockets would be needed to get Curiosity to the surface. The sheer size of the descent stage would result in a daunting engineering challenge: how to get a car-size rover safely down to the surface from a perch many feet above the ground atop the upper deck of its lander?
 
"This rover is 900 kilograms, it is a beast, it is the size of a car," said Steve Sell, an entry, descent and landing engineer at the Jet Propulsion Laboratory. "So you're trying to land something very heavy, so that means you need sizable engines."
 
More powerful rocket engines would kick up billowing clouds of dusty debris as the lander approached touchdown "so you tend to want to keep the engines farther away from the surface," Sell said.
 
"That makes you want to have longer legs, and having longer legs means your center of gravity is higher and then it's much easier to tip over," he said. "Or you need to be very wide. It tends to drive you (to a) larger and larger (lander) in order to do that and be stable."
 
Then there is the little matter of getting the rover down to the surface after landing.
 
"Let's say you solved all that and were able to land and you now had to drive a one-ton rover off the top of a platform, either down ramps or some other kind of mechanism," Sell said. "If you were oriented in a way that maybe wasn't favorable to your wheels, like you were tilted to your side and had to drive either forward or backward to get off the platform, you could slide sideways off the ramps. Maybe there are rocks where the bottoms of the ramps would normally touch and you can't deploy the ramp in the first place."
 
Faced with those and other sobering scenarios, the MSL engineers came up with a novel alternative solution. Instead of rolling the costly rover off an elevated, possibly tilted lander, why not do away with the landing legs altogether? Why not attach the rover to the bottom of the rocket-powered descent stage and then lower it directly to the surface on the end of a long cable?
 
It was a seemingly crazy idea, but it would solve a host of technical challenges, leaving the rover ready to begin its mission without any risky post-landing maneuvers to deploy and roll down ramps of some sort to reach the surface.
 
But the so-called "sky crane" concept brought its own set of challenges. Unlike the kind of crane one might find on Earth, this one has to fly, using eight rocket engines, two on each corner. There is no cab, and the nearest operator is 154 million miles away, with 14 minutes between every action its confirmation.
 
The rover and its jet pack would have to handle the challenging descent autonomously and, during the last few hundred feet, carry out the sky crane maneuver, a never-before-attempted two-body balancing act.
 
"First, you think it's crazy. Then, you know, you're like OK, all right, maybe it'll work, but you're still crazy," laughed Sell.
 
"Eventually people come around to saying OK, this makes sense. When you break it down, it is really the result of very careful, reasoned thought and what we all believed were the best choices to land something this big in the most efficient way possible."
 
Said Doug McCuistion, director of Mars exploration at NASA Headquarters: "Once you get comfortable, once you understand it, it's not a crazy concept. It works."
 
"Is it risky? Landing on Mars is always risky," he said. "There are hundreds of discrete events that occur (and) any one could cause problems. We go from 13,000 mph to zero in seven minutes. That's quite a challenge in itself. And then there's the unknown, there's Mars. Mars throws things at you -- dust storms, atmospheric density changes, wind. So it's a very unique and challenging environment."
 
Entry, descent and landing -- EDL -- will begin 10 minutes before atmospheric entry when Curiosity and its descent stage, tucked away inside a protective heat shield and backshell, separate from the drum-shaped cruise stage that provided power, communications and propulsion during the long flight to Mars.
 
One minute later, thrusters will fire to cancel out the spacecraft's 2-rpm rotation and the vehicle will re-orient itself heat shield forward. Two 165-pound tungsten weights then will be ejected, changing the spacecraft's center of mass to provide aerodynamic lift.
 
Controlling that lift during the high-speed portion of entry is what will enable Curiosity's flight computer to precisely target the landing zone in Gale Crater, steering as required to compensate for differences in atmospheric density, wind speed and other variables.
 
MSL is the first robotic mission to attempt a guided entry.
 
"Although we're using the Apollo algorithms and had help from a lot of people who've worked on that stuff in the past, this thing doesn't land successfully if guided entry doesn't work because we've got to kill the energy," said Project Manager Pete Theisinger. "So that part of it's got to work well."
 
Added Sell: "It's not really so much that you worry your guidance algorithm is wrong. It's the unknown unknowns. I know we've handled all of the things we've thought about, and I'm confident that as long as we haven't missed something that everything's going to work great. ... We're counting on it to work."
 
Curiosity will slam into the discernible atmosphere of Mars at an altitude of about 81 miles and a velocity of 13,200 mph. At that point, it will be about 390 miles -- seven minutes -- from touchdown in Gale Crater
 
One minute and 15 seconds after entry, the spacecraft's heat shield will experience peak temperatures of up to 3,800 degrees Fahrenheit as atmospheric friction converts velocity into heat, accounting for 90 percent of the spacecraft's deceleration.
 
Ten seconds after peak heating, that deceleration will max out at 15 times the force of Earth's gravity at sea level.
 
Plummeting toward Mars, the rover's flight computer will continue to steer the spacecraft as required, firing thrusters to make subtle changes in the flight path to compensate for actual atmospheric conditions.
 
The guided entry phase of flight will come to an end about four minutes after entry. Six 55-pound weights will be ejected to move the center of mass back to the central axis of the spacecraft to help ensure stability when its parachute deploys.
 
At that point, at an altitude of about seven miles and a velocity of some 900 miles per hour, the huge chute will unfurl and inflate to a diameter of 51 feet, delivering a 65,000-pound jolt to the still-supersonic spacecraft.
 
"We have done a series of tests, but none of them have been at Mars-like conditions," Sell said. "This is a supersonic chute, we're deploying it at about mach 1.7, which we've done in the past on Mars, we're not deploying faster than we have in the past. But what we are doing is we're deploying the largest chute we've ever flown."
 
The inflation load of 60,000 pounds or so is "the amount of force the chute will experience when it first inflates and catches that first blast of supersonic air. We're never able to test it at supersonic speeds on Earth, so there's always that chance that there's something missed there, there's a percentage chance or so that the chute won't inflate the way we expect it to."
 
Assuming it does, in fact, inflate as expected, the heat shield will be jettisoned 24 seconds later, at an altitude of about five miles and a descent rate of 280 mph, exposing the rover's undercarriage to view.
 
A sophisticated radar altimeter will begin measuring altitude and velocity, feeding those data to the rover's flight computer, and a high-definition camera will begin recording video of the remaining few minutes of the descent.
 
"It does eight frames per second, high-definition-quality video from the backshell coming off (all the way) to the ground," Theisinger said. "So it's a lot of data, it'll take a long time to get it back. But it should be a tremendous movie when it does."
 
Six minutes after entry, plunging toward Mars at nearly 200 mph just a mile or so from the surface, the most critical moments of the descent will begin as the rover and its rocket pack are cut away from the parachute and backshell, falling like a rock through the thin martian atmosphere.
 
An instant later, eight hydrazine-burning rocket engines, two at each corner of the descent stage, will ignite to stabilize and quickly slow the craft's vertical velocity to less than 2 mph.
 
Then comes the moment of truth for the sky crane concept.
 
Just before the maneuver begins, four of the eight rocket engines, one on each corner, will shut down. Then, about 15 seconds before touchdown, at an altitude of just under 70 feet, Curiosity will be lowered on the end of a 25-foot-long tether. As the support and data cables unreel, the rover's six motorized wheels will snap into position for touchdown.
 
Finally, seven minutes after the entry began and descending at a gentle 1.7 mph, Curiosity's wheels will touch the surface of Mars. Radio confirmation of landing is expected at 1:31 a.m. EDT on Aug. 6 -- about 3 p.m. local time on Mars -- but atmospheric conditions and other factors could result in a touchdown 40 seconds or so to either side of that target.
 
Whatever the actual timing, the flight computer, sensing "weight on wheels," will send commands to fire small explosive devices that will sever the cables connecting Curiosity with the still-firing propulsion system.
 
Its work done, the descent stage will fly away to a crash landing at least 500 feet away and possibly twice that far. Curiosity, meanwhile, will continue sending telemetry to NASA's orbiting spacecraft for relay back to Earth where engineers will be standing by for post-landing health checks.
 
"Of anything I could possibly be disappointed with in this mission, there's not somebody standing there (on Mars) with a camera filming the whole thing from the surface," Sell said.
 
Despite the unconventional approach, Theisinger said he's confident the system will work as designed.
 
"There have been typical development questions, like when we separate the rover from the descent stage, do we make sure we can control the cables and all the things we have to cut in an intelligent way? And we've done some testing and uncovered a couple of small issues that we've had to fix," he said.
 
"But the big questions, there's never been a show stopper in the big questions, about controllability, the descent or anything like that. We've done field testing with the radar both on an F-18 (jet) with high-velocity, high-altitude tests, we've done it with a helicopter with low velocity and low altitude and the radar's behaved very, very well.
 
"We're confident the design is solid. Now, it's a complex thing so everything's gotta work and there are a lot of little things that have to work. But the design is solid."
 
Relay sats provide ringside seat for Mars landing
 
William Harwood - CBS News
 
To help scientists and engineers follow the action 154 million miles away, the trajectory of the Mars Science Laboratory was set up to make sure the rover's descent to the surface of the red planet occurs within view of three orbiting satellites.
 
NASA's Mars Odyssey and the Mars Reconnaissance Orbiter, along with the European Space Agency's Mars Express satellite, will capture telemetry from the Mars Science Laboratory as the spacecraft makes its nail-biting seven-minute plunge to the floor of Gale Crater early Monday U.S. time.
 
But Odyssey is the only one of the three capable of "bent pipe" realtime relay, sending the UHF telemetry directly back to Earth to give anxious engineers what amounts to continuous play-by-play updates, including confirmation of landing.
 
Touchdown is expected at 1:17 a.m. EDT (GMT-4) on Aug. 6, but confirmation will take 13.8 minutes to cover the 154 million miles between Earth and Mars, arriving around 1:31 a.m.
 
Unexpected problems with Odyssey's attitude control system in June changed the satellite's orbit slightly, putting it out of position for realtime data relay.
 
But on July 24, a short rocket firing was carried out that moved the spacecraft six minutes ahead in its orbit. That should enable it to beam back telemetry during most of Curiosity's descent as originally planned.
 
"Odyssey has been working at Mars longer than any other spacecraft," Gaylon McSmith, Mars Odyssey project manager, said in a NASA statement. "So it is appropriate that it has a special role in supporting the newest arrival."
 
MRO will record telemetry throughout the descent and play it back after processing. That data should start reaching Earth several hours after landing. MRO also will attempt to snap a picture of the MSL descent stage after parachute deploy.
 
The Mars Express will record most of the descent and then turn back toward Earth to relay the stored telemetry to European flight controllers. They will quickly pass it along to NASA.
 
But Odyssey is the key to realtime confirmation of a successful landing.
 
"It'll depend on how well the link is performing, what the geometry is," said Steve Sell, an entry, descent and landing engineer at the Jet Propulsion Laboratory.
 
"There's some uncertainty in our touchdown time just based on winds, how long we're on the parachute, atmospheric density, things like that can actually spread our landing time by about plus or minus a minute or so," he said. "So depending on exactly when we touch down determines how long we actually keep that Odyssey link active."
 
As a backup, the Mars Science Lab also will transmit simple tones directly back to Earth during the descent that will check off major events. But Earth will drop below the horizon as viewed from Curiosity well before landing, cutting off direct line-of-sight communications.
 
"The spacecraft will transmit what we call X-band tones," Project Manager Pete Theisinger told reporters earlier this month. "The landing site's not visible from Earth at the time of landing, so those tones will cease to be received on Earth sometime between the time the parachute deploys and the heat shield separates. So at that point, we will know it's there and we should see (the velocity change confirming) the parachute deploy.
 
"MRO will get the full extent of the entry, descent and landing from before entry until after landing. But that's a store-and-forward system and so the data will be returned to Earth three or four hours later."
 
Why Mars again? A look at NASA's latest venture
 
Alicia Chang - Associated Press
 
NASA's new robot rover named Curiosity has spent 8½ months hurtling through space toward its destination Sunday on Mars. It is set to land near the foot of a mountain rising from a giant crater. This marks NASA's 19th mission and eighth landing attempt.
 
Why Mars again?
 
The big unknown remains. Scientists want to know if any form of life ever existed there, and that means microscopic organisms. Since the 1960s, spacecraft have zipped past, orbited or landed on Mars in this quest. Two small NASA rovers that arrived in 2004 explored different craters and one is still functioning today.
 
Curiosity is the most ambitious effort ever, but it's not the be-all and end-all. During its two-year exploration, it will try to answer whether the giant crater where it lands had the right conditions to support microbes. But future missions would still be needed for more answers.
 
What will Curiosity do?
 
Curiosity carries a toolbox of 10 instruments, including a rock-zapping laser and a mobile organic chemistry lab. It also has a long robotic arm that can jackhammer into rocks and soil. It will hunt for basic ingredients of life including carbon-based compounds, nitrogen, phosphorus, sulfur and oxygen, as well as minerals that might provide clues about possible energy sources.
 
How did Curiosity get its name?
 
The spacecraft is formally called the Mars Science Laboratory. In 2008, NASA held a naming contest open to students and selected Curiosity, proposed by a sixth-grader from Lenexa, Kan.
 
What does this mission cost?
 
$2.5 billion. That's $1 billion over its original budget. Curiosity was supposed to launch in 2009 and land in 2010, but development took longer than expected. The delay gave engineers more time to debug problems and test the spacecraft, but also put the project over budget.
 
When will we send astronauts to Mars?
 
President Barack Obama has set a goal for astronauts to orbit Mars by the mid-2030s followed by a landing. Before that can happen, the plan is to send astronauts to an asteroid first.
 
NASA to broadcast Mars Rover Landing from NYC's Times Square Sunday night
 
Space.com
 
NASA's biggest Mars rover landing yet is about to hit Broadway.
 
New Yorkers hoping to see the Aug. 5/6 landing of NASA's huge Mars rover Curiosity alongside like-minded space fans can head to Times Square here on Sunday night (Aug. 5) to catch the rover's touchdown on the Red Planet live on a giant LED television screen.
 
NASA Television's coverage of the agency's $2.5 billion Mars Science Laboratory mission landing will be broadcast live on the Toshiba Vision screen that hangs below the iconic New Year's Eve ball in Times Square, space agency officials say.
 
The broadcast begins at 11:30 p.m. EDT Sunday and runs until 4 a.m. EDT Monday. The exact time of landing is scheduled for 1:31 a.m. Aug. 6 EDT (0531 GMT), though it will be late Monday night at the rover's California-based mission control room.
 
"In the city that never sleeps, the historic Times Square will be the place for New Yorkers to participate in this historic landing," John Grunsfeld, NASA's associate administrator for science missions, said in a statement today (July 31). "When you think of all the big news events in history, you think of Times Square, and I can think of no better venue to celebrate this news-making event on Mars."
 
NASA Curiosity probe is a Mini Cooper-size rover designed to spend two years exploring the vast Gale Crater in pursuit of some of Mars' biggest mysteries, including the question of whether water, and maybe even life, ever existed there. The rover launched in November 2011 and is now poised to land in a nail-biting maneuver this weekend involving a hovering rocket-powered "Sky Crane" that will lower the vehicle to Mars' surface via tethers.
 
The landing broadcast will originate from Mission Control at NASA's Jet Propulsion Laboratory's in Pasadena, Calif., which designed the rover and is managing the mission. If the landing is successful, viewers will be able to see scientists receive the first signal from the rover on Mars.
 
The audio track for the broadcast will be carried on the online radio station Third Rock Radio, which can be accessed from the NASA homepage at and through the Tuneln mobile app.
 
"We're pleased the Toshiba Vision screens will offer a unique view of this great scientific achievement, the landing of the rover Curiosity on Mars," said Eddie Temistokle, senior manager of corporate communications and corporate social responsibility for Toshiba America Inc.
 
Other sites around the country, including many of the NASA centers, will also host live viewing events for the landing, which is NASA's most ambitious and expensive planetary mission on the horizon.
 
To find a Mars rover landing event near you, check NASA's complete listing of events here: http://go.nasa.gov/QtmuY7
 
NASA's webcast of the entire Mars rover Curiosity landing will begin at Aug. 5 at 11:30 p.m. EDT (0330 Aug. 6 GMT) on NASA TV here: http://www.nasa.gov/ntv
 
New York's Times Square to broadcast Mars landing
 
Agence France Presse
 
The highly anticipated landing of NASA's sophisticated $2.5 billion rover on Mars will be broadcast on a large screen in New York City's Times Square, NASA said on Tuesday.
 
The touchdown of the Curiosity rover, equipped with a sophisticated roving toolkit for analyzing the terrain for signs that microbial life once existed, is scheduled for August 6 at 1:31 am Eastern time (0531 GMT).
 
A rocket-powered sky crane aims to lower the car-sized vehicle on to the surface of the red planet so it can embark on a two-year science mission.
 
Viewers will not be able to see real-time video of the landing -- no one will -- but the live images will show staff at mission control at NASA's Jet Propulsion Laboratory in California as they await the signal that the rover touched down.
 
The images will be on the Toshiba Vision screen, located just below the world-famous New Year's Eve ball in Times Square.
 
"In the city that never sleeps, the historic Times Square will be the place for New Yorkers to participate in this historic landing," said John Grunsfeld, associate administrator for NASA's Science Mission Directorate.
 
"When you think of all the big news events in history, you think of Times Square, and I can think of no better venue to celebrate this news-making event on Mars."
 
END