World Bulletin/News Desk
By the time the robotic Mars laboratory dubbed Curiosity streaks into the thin Martian atmosphere at hypersonic speed on Sunday night, the spacecraft will be in charge of its own seven-minute final approach to the surface of the Red Planet.
With a 14-minute delay in the time it takes for radio waves from Earth to reach Mars 154 million miles (248 million km) away, NASA engineers will already have given Curiosity the last commands of its voyage through space.
At that point, the mission control team at the Jet Propulsion Laboratory (JPL) near Los Angeles will have little more to do than anxiously track the spacecraft's progress - and wait.
Curiosity's fate will then hinge on the performance of its pre-programmed directions, a new self-guided flight system and a complex, seemingly far-fetched landing sequence that includes a giant parachute and a never-before-used, jet-powered "sky crane" that must descend to the right spot over the planet, lower Curiosity to the ground on a tether, cut the cords and fly away.
No wonder NASA half-jokingly calls it "the seven minutes of terror."
"We are all just along for the ride," said JPL's Adam Steltzner, who is overseeing the entry, descent and landing phase of the spacecraft, formally known as the Mars Science Lab.
While a great deal of groundbreaking technology has gone into delivering the one-ton, six-wheeled, nuclear-powered rover to Mars, the thrust of the $2.5 billion project is the two-year scientific mission that follows.
Curiosity, billed as the first full-fledged analytical laboratory on wheels ever sent to another world, is designed primarily to search for evidence that Mars may have once harbored conditions favorable to microbial life.
Getting there remains a big hurdle. And the period of maximum danger begins as Curiosity, encased in a protective shell, pierces the Martian atmosphere at roughly 13,000 miles (20,921 km) per hour, 17 times the speed of sound on Earth.
The lag in radio transmissions between the two planets means that by the time NASA engineers receive an atmospheric entry signal from Curiosity, the spacecraft will already have landed - either intact or in pieces.
But if all goes as planned, NASA's team expects to receive another radio signal by just after 10:30 p.m. Pacific time (1:30 a.m. EDT on Monday/0530 GMT on Monday), confirming that Curiosity has touched down safely in its target zone near the foot of a towering mountain on the floor of a vast impact crater named Gale Crater.
If no landing signal comes, it could take hours or days for scientists to learn whether radio communications with the rover were merely disrupted or that it crashed or burned up during descent.
Mission directors said they were confident the rather unorthodox landing sequence devised for Curiosity will succeed.
"It looks a little crazy, but I promise you it's the least crazy of the methods you could use to land a rover the size of Curiosity on Mars, and we've become quite fond of it," Steltzner told reporters at a JPL briefing on Thursday.
Over twice as large and five times heavier than either of the twin rovers Spirit and Opportunity that landed on Mars in 2004, Curiosity weighs too much to bounce to the planet's surface in airbags or to fly itself to the ground with rocket thrusters, systems successfully used by six previous NASA landers.
Instead, rocket power will be used in combination with several other components during Curiosity's descent and landing.
Plunging through the top of Mars' atmosphere at an angle producing slight aerodynamic lift, the capsule's "guided entry" system uses jet thrusters that actually steer the craft as it falls, making small course corrections on the way down.
At an altitude of 7 miles (11 km) and a velocity of 900 mph (1,448 kph), a giant parachute will open, and in less than half a minute, the heat shield will fall away, exposing the underside of the rover.
A minute and a half later with the craft now about a mile high and falling at nearly 200 mph (322 kph), the back shell of the capsule and the parachute are jettisoned, leaving the rover attached only to the belly of a jet pack called a sky crane.
Eight jet thrusters on the crane immediately fire, jerking the craft out from under the parachute and abruptly slowing Curiosity's descent to about 1.5 mph (2.4 kph) as it nears the surface.
The sky crane then lowers the rover to the ground on nylon tethers that unspool from beneath the hovering jet pack. The cords are severed once Curiosity's wheels are on the surface, and the sky crane flies off to crash a safe distance away.
So hopeful are they of the sky crane's success that NASA officials see it as a model for the next generation of landers.
"I think what we have is a workhorse for the future," said Doug McCuistion, NASA's mars exploration program director.
Still, the engineers at mission control are leaving nothing to chance - not even superstition. In keeping with a decades-long tradition, the NASA flight team plan to break out a can of peanuts about an hour before touchdown, said David Oh, a flight director.
"Landing day will take all the good engineering and all the luck we have," he said.
Apple is striving to improve the environmental impact of its supply chain, which is responsible for more than 70 percent of its total carbon footprint, the official Xinhua news agency reported.
Social network to be integrated into Windows software in coming months, CEO says
New supermarket features no human cashiers, scheduled to open to public in early 2017
The organization cited missing letters in some words or mistakes in verses and punctuation in free Quran apps
The intervention in a Chinese company’s bid to buy German chip maker, Aixtron, comes after Chinese companies have spent billions to acquire technology in Europe and the United States.
Malware designed for cellphones are designed to steal email addresses and authentication data stored on the devices to access sensitive data from Gmail, Google Photos, Google Docs and other services, Check Point said.
Japan plans to build the world's fastest-known supercomputer as part of a government policy to get back Japan's mojo in the world of technology
The once-mighty Finnish company sold its device business to Microsoft in 2014, where phones were sold under the Lumia brand. But as Microsoft effectively exits the smartphone business, Nokia is set to return.
South Korea denied a request by Google to export digital-map date
Day after releasing new anti-harassment policies, company promotes ad for white supremacists
On trip to US, senior executives in tech industry tell investors of opportunities offered
Facebook today announced that it has purchased CrowdTangle, a 4-year-old tool that publishers use to track how content spreads around the ...
Moscow City Court has upheld a ruling to block the LinkedIn professional network website.
Neither Tesla nor Grohmann have offered details of how much money is to change hands with the Tesla purchase of Grohmann
The presidential election is being debated extensively in the world media. One of the most important topics of discussion is the effect of Google on the US election. Donald Trump has accused Google of manipulating the remaining weeks and hours are now left behind. Trump accused has Google of hiding negative search results about Clinton and showing Clinton ahead in the polls.