he SUV-size rover and a tiny robotic helicopter are scheduled to touch down on Mars on Thursday, beginning quest to find evidence of past biological activity
The lander carrying Perseverance will plunge to the surface of Mars in what NASA engineers call ‘seven minutes of terror.’
PHOTO: NASA/JPL-CALTECH/AGENCE FRANCE-PRESSE/GETTY IMAGESIf alien life once existed on Mars, scientists may finally be poised to find traces of it. After a seven-month, 292-million-mile journey, NASA’s biggest, fastest and brainiest rover ever—Perseverance—is nearing its highly anticipated touchdown on the Red Planet.
The $2.7 billion rover, which is scheduled to land at 3:55 p.m. EST on Thursday, embodies the latest and most ambitious effort by NASA to find evidence of past life on Mars. Though it is now a barren place of icy dunes, dust devils, dead volcanoes and subzero winds, scientists believe Mars in its remote past may have been a comparatively lush, warm world—one suitable for the chemistry of life.
“It will attempt to answer an age-old question that has eluded humanity for generations: whether life has ever existed elsewhere beyond our own planet,” Thomas Zurbuchen, associate administrator for the space agency’s science mission directorate in Washington, said of the Perseverance mission.
Bristling with sensors, cameras, microphones and a robotic arm, the one-ton, SUV-size Perseverance rover is designed to look for rock or soil specimens that might harbor evidence of ancient life and pack what it finds into small tubes, to be cached for retrieval by future missions and brought back to Earth for analysis. NASA and the European Space Agency are discussing several mission scenarios that might return these samples by 2031, NASA officials said.
Previous Ventures
If all goes well, NASA’s Perseverance rover will join four previous robotic vehicles that pioneered exploration of the red planet.
Sojourner (1997)
Spirit (2004)
As the first rover on Mars, Sojourner was small and simple. It was about as long as a clarinet and weighed 25 lbs. It took pictures and sampled rocks. The winds of Mars kept dust off its solar panels, allowing it to last longer than expected.
Spirit was one of two larger rovers sent as a pair. Each one was about 5 feet long and weighed about 383 pounds. Spirit found rocks suggestive of hot springs, photographed a dust devil, and scaled a Martian mountain before becoming trapped in loose sands.
Opportunity (2004)
Curiosity (2012)
Still active, the Curiosity rover is about 9 feet long and weighs almost a ton. It gathered evidence that the crater basin where it landed was once an oasis.
Identical to Spirit, Opportunity landed on the opposite side of Mars. There, it discovered convincing signs that water had once flowed on the surface.
Total distance traveled
Total pictures taken
0 miles
10
20
30
0
250,000
500,000
750,000
328 feet
Sojourner
Sojourner
550 pictures
Spirit
Spirit
Opportunity
Opportunity
Curiosity
Curiosity
Still
active!
Years active on Mars
Initial mission length
Actual
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Sojourner
Spirit
Opportunity
Curiosity
Perseverance
(planned)
Perseverance (2021)
Set to land on Feb. 18, NASA’s newest rover, Perseverance, is about 10 feet long and weighs just over a ton. It carries seven instruments to test for evidence of past Martian life and prepare samples for return to Earth. It also carries an experimental helicopter for test flights.
Source: NASA
During its two-year mission, Perseverance will roam the surface and look for traces of organic matter, which could be evidence of primordial microbes or other simple life-forms. Other places in the solar system—from the searing clouds of Venus to the frozen oceans of moons around Jupiter and Saturn—might also have the potential for life. But those places are considered even more inaccessible than Mars.
Perseverance is accompanied by the first helicopter to be transported to another world. NASA engineers expect to conduct several test flights of the four-pound drone, called Ingenuity. These would be the first powered controlled flights on another planet.
“It will truly be a Wright Brothers moment, but on another planet,” said MiMi Aung, Ingenuity’s project manager at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
But getting Perseverance and Ingenuity on the ground won’t be easy.
ABOUT 10 MINUTES FROM LANDING
The spacecraft sheds solar panels, radios, and fuel tanks used during its flight to Mars. Only its protective aeroshell—with rover and descent stage inside—makes the trip to the surface. About 80 seconds after entering the atmosphere, the heat shield reaches about 2,370 degrees Fahrenheit. Safe in the aeroshell, however, the rover gets up to only about room temperature.
SIX MINUTES, 50 SECONDS FROM LANDING
Turbulence rocks the spacecraft as it descends, potentially nudging it off course. To compensate, it fires small thrusters on its backshell that adjust its angle and direction of lift. This “guided entry” technique helps the spacecraft stay on the path to its downrange target.
THREE MINUTES FROM LANDING
To balance its center of gravity, the spacecraft automatically ejects a half dozen small weights used to tilt the craft at the right angle for initial re-entry, preparing it for the parachute deployment.
TWO MINUTES, 45 SECONDS FROM LANDING
Parachute deploys, slowing the spacecraft from around 940 mph to around 200 mph. The spacecraft uses a new technology—Range Trigger—to calculate its distance to the landing target and open the parachute at the ideal time to hit its mark.
TWO MINUTES, 25 SECONDS FROM LANDING
The spacecraft jettisons its heat shield, exposing the Perseverance rover to the onrush of air. Immediately, the rover starts photographing the approaching ground and using radar to figure out its altitude. The onboard computer compares the position data to an onboard map.
ONE MINUTE FROM LANDING
To slow down even more to its safe touchdown speed, the craft releases its back shield and cuts free of the parachute. It fires its eight descent stage engines. It maneuvers side-to-side to avoid the ejected parachute and shell.
12 SECONDS FROM LANDING
Hovering about 66 feet above the surface, the descent stage lowers the rover on a set of cables about 21 feet long. Meanwhile, the rover unstows its mobility system, locking its legs and wheels into landing position.
TOUCHDOWN
The rover lands safely in a 28-mile-wide ancient lake bed called the Jezero Crater. It cuts the tethers keeping it tied to the descent stage. This frees the descent stage to fly off and land at a safe distance from Perseverance.
Following a harrowing plunge through the salmon pink skies and blue clouds of Mars—what NASA engineers call “seven minutes of terror”—the lander carrying Perseverance and Ingenuity will settle on an ancient lake bed called Jezero Crater. It is the smallest, most rugged landing zone upon which the space agency has ever attempted a landing.
Once the lander begins its automated descent, mission controllers on Earth will have no contact with it—and no way to control it—until it has landed. Radio transmissions take 11 minutes, 22 seconds to travel from one planet to the other—far too long to allow for controllers here on Earth to guide the craft.
Mission engineers radioed the spacecraft its pre-landing commands on Monday, activating onboard systems for entry, descent and landing and setting the stage for what may be the most daring engineering maneuver in interplanetary exploration. They said they didn’t expect any last-minute course corrections.
“The targeting is on the bull’s-eye,” said Jennifer Trosper, Perseverance deputy project manager at the Jet Propulsion Laboratory. “Perseverance is operating perfectly now and all systems are ‘go’ for landing. The spacecraft is focused. The team is focused.”
Type of mission
Country of Origin
Upcoming missions
Lander
Rover
Soviet Union
or Russia
U.S.
European
Union
China
Failed landing or swift malfunction
Phoenix
Viking 2
Rosalind Franklin*
Huoxing-I
Viking 1
Perseverance
Pathfinder & Sojourner
Beagle 2
Insight
Opportunity
Curiosity
Schiaparelli EDM
Spirit
Mars 6
Mars 3
Mars 2
Mars Polar Lander
Rosalind Franklin, expected to land on Mars in 2023, is a joint effort between Roscosmos State Corporation for Space Activities and the European Space Agency.
Source: NASA
The lander, which carries Perseverance and Ingenuity inside a protective shell, will be going about 12,100 miles an hour—about 3 miles a second—when it enters the Martian atmosphere at 3:48 p.m. Thursday. Friction from the thin air will slow the craft and heat it to a temperature of about 2,370 degrees Fahrenheit. That is hot enough to melt cast iron.
Next, the lander will deploy a 70-foot-wide parachute, the largest high-speed chute ever constructed. Seconds later, the craft will jettison its protective heat shield and fire its retro rockets. As it descends, the lander’s onboard navigation should help it steer clear of obstacles on the ground below.
Once the lander comes within a few feet of the surface, it should lower Perseverance to the surface on cables, like a crane lowering a heavy package. Soon thereafter, NASA engineers expect to receive a signal indicating that Perseverance is safely on the ground.
“We [will] have a brand-new baby spacecraft ready to start rolling around,” said Erisa Stilley, Perseverance entry, descent, and landing systems engineer at the Jet Propulsion Laboratory.
If the landing succeeds, it will be the ninth time NASA has managed to land a craft safely on Mars since it first successfully parked a lander on the planet’s surface in 1976. More than half of attempted landings on the Red Planet have failed.
China’s Tiawen-1 probe, which entered orbit around Mars last week, is expected to make the country’s first landing on the planet in May.
“Mars is hard, and we never take success for granted,” said Dr. Zurbuchen. “We are entirely focused on one thing right now—a successful landing.”
Trends is an amazing magazine Blogger theme that is easy to customize and change to fit your needs.
No comments
Post a Comment