Seven Minutes of Terror

“Seven Minutes of Terror,” Eight Years of Ingenuity

“Sometimes when we look at it, it looks crazy,” remarked Adam Steltzner, an engineer who works for the National Aeronautics and Space Administration— known more commonly to the world as NASA. “It is the result of reasoned engineering thought. But it still looks crazy.”

In a video story entitled “Seven Minutes of Terror,” Steltzner was joined on camera by an eloquent cast of entry‐descent‐landing engineers (or “EDL Engineers”). Working from the Jet Propulsion Laboratory (JPL) in California, their team introduced the world to one of the most daring, inventive feats of engineering the world had ever witnessed: the pinpoint landing of NASA’s Curiosity rover on Mars.

The seven minutes explored in that story—and experienced by the world in early August 2012—took place after seven years of engineering, one year of space flight, and countless hours of collaboration on the perfect landing. Dubbed the Mars Science Laboratory (“MSL”), this mission brought together more than 7,000 people, working in organizations from all over the world, to accomplish its goals. Split into two parts, the launch and the landing, MSL is one of the greatest technological accomplishments of human history.

The most impressive thing about MSL is that no mission this ambitious had ever been attempted in the past. The landing presented problems that could not be compared directly to anything done before. But thanks to the rigorous work of hundreds of engineers, NASA ended up making a new mark on Mars.

The Launch The MSL launch took place on November 26, 2011. Blasting from the Earth at a speed of 12,582 miles per hour, the rockets that broke free of Earth’s orbit and sent the Mars‐bound spacecraft with the rover on its way were the most routine part of the mission. For decades NASA has specialized in space launches, drawing on some of the brightest minds on the planet to determine what it takes to bring a spacecraft to the stars.

Planning the rover’s trip to the red planet (Mars’s nickname, due to its color)—a voyage lasting about 36 weeks at maximum cruise velocity—was also not exactly a new challenge for engineers working on the MSL mission. NASA had already landed two rovers, named “Spirit” and “Opportunity,” on the surface of the red planet. Based on the principles of astronomy, the launch engineers at JPL had very precise requirements for making the journey from Earth to Mars.

The key to these requirements was an understanding of orbits. Although Mars is significantly farther from the sun than Earth, both planets orbit the same star. Their distance from each other changes during each cycle, but Earth comes into alignment with Mars once every 26 months—“lapping” it in a perpetual race around the sun. Observing this pattern, astronomers can work with engineers to pinpoint the optimal month, day, and time for a spacecraft to leave Earth on a speedy one‐way trip.

Drawing on centuries of knowledge of the laws of physics, scientists designed rockets and a spacecraft to accommodate Curiosity. Years of calculation, construction, careful planning and computer modeling resulted in a vessel that cruised purposefully through space, reaching the orbit of Mars at just the right time to attempt a landing.

Through it all, the margin for error was nearly non‐existent. The movement of interplanetary bodies in space is much more demanding than the movement of cars on a highway, or even airplanes in the stratosphere. Miscalculating a vector or failing to account for any aspect of the orbits could lead to a $2 billion failure.

Fortunately, NASA had taken on this challenge before. Its engineers had both the experience and the tenacity to succeed again. What came after the launch was different story.

The Landing Spirit and Opportunity, the two NASA rovers that landed on Mars in 2004, used a combination of parachutes, rockets, and hi‐tech airbags to protect themselves. Much like launch and spaceflight, each step of the landing sequence was planned and simulated to the very last detail. Learning from a prior Mars mission, EDL engineers were able to recreate some of the same maneuvers used in that sequence.

Unfortunately, the specific requirements of MSL made it difficult to depend on past experience. While NASA had constructed the biggest supersonic parachute ever made, parachuting was far from enough. Since the atmosphere of Mars is 100 times thinner than the atmosphere of Earth, the parachute alone could not reduce the speed of descent past 200 miles per hour—a breakneck speed that would surely damage Curiosity upon landing.

Curiosity outweighed any earlier rover and contained over 150 pounds of sensitive scientific devices, so an airbag solution was ruled out. Instead, EDL engineers designed a maneuver that would allow the entry capsule to turn sharply and activate powerful rockets to finish the job. Once this maneuver was complete, the capsule could attempt a vertical landing.

Successfully executing the switch from a parachute entry to a controlled, rocketfueled descent was a feat that could have gone wrong at any moment. Still, even this was not enough to succeed. Once the parachute was cut, and a full radar system was online to guide Curiosity to the surface, the force from the rockets could kick up so much dust that the dust itself would damage the rover.

Eternally thinking one step ahead, EDL engineers designed a device called a “sky crane” to complete the final step of the landing sequence. When the sky crane was 20 feet above Martian soil, it lowered Curiosity onto the surface with a set of cables.

Moving from 13,000 miles per hour to zero miles per hour in just seven minutes, Curiosity finally touched down. The capsule, with all rockets still firing, blasted back into the sky and crash‐landed elsewhere on the planet. The landing was a success.

The Ongoing Mission MSL is the latest of NASA’s attempts to learn more about Mars. The most popular inquiry is whether Mars may have, at any point in its long history, supported life as we know it. The search for these signs, however, is one piece of a much greater picture.

The mission has eight scientific objectives, each one broken into specific goals and all coming together to form a more detailed understanding of all things Mars. Curiosity, a rover the size of a station wagon, contains advanced instruments that will help it probe, sample, record, and analyze its way through Martian terrain. Collecting evidence on the biological, geological, chemical, and radiological profile of the red planet will prepare NASA for the next space flight to Mars. Another rover mission, building on the work of Curiosity, is planned to launch in 2020.

Ultimately, scientists hope to learn enough about Mars to bring human beings to the surface for a manned research mission. Some, working with entrepreneur Elon Musk, are even devising a plan to colonize the planet just one decade later. Skeptics debate whether or not such a seemingly outrageous idea could ever be made into reality.

Looking back at NASA’s solutions to the great technical challenge of the Curiosity landing, it’s hard to feel too skeptical about humankind’s ability to reach for the stars.

Based on this information, the reader can conclude that ­­--

• the landing was a success.

• landing on Mars required a great deal of resources and planning.

• the complex nature of the landing was partly due to the location of Mars.

• engineers had an important role in the rover’s successful landing.

“Seven Minutes of Terror,” Eight Years of Ingenuity“Sometimes when we look at it, it looks crazy,” remarked Adam Steltzner, an engineer who works for the National Aeronautics and Space Administration— known more commonly to the world as NASA. “It is the result of reasoned engineering thought. But it still looks crazy.”

In a video story entitled “Seven Minutes of Terror,” Steltzner was joined on camera by an eloquent cast of entry‐descent‐landing engineers (or “EDL Engineers”). Working from the Jet Propulsion Laboratory (JPL) in California, their team introduced the world to one of the most daring, inventive feats of engineering the world had ever witnessed: the pinpoint landing of NASA’s Curiosity rover on Mars.

The seven minutes explored in that story—and experienced by the world in early August 2012—took place after seven years of engineering, one year of space flight, and countless hours of collaboration on the perfect landing. Dubbed the Mars Science Laboratory (“MSL”), this mission brought together more than 7,000 people, working in organizations from all over the world, to accomplish its goals. Split into two parts, the launch and the landing, MSL is one of the greatest technological accomplishments of human history.

The most impressive thing about MSL is that no mission this ambitious had ever been attempted in the past. The landing presented problems that could not be compared directly to anything done before. But thanks to the rigorous work of hundreds of engineers, NASA ended up making a new mark on Mars.

The Launch The MSL launch took place on November 26, 2011. Blasting from the Earth at a speed of 12,582 miles per hour, the rockets that broke free of Earth’s orbit and sent the Mars‐bound spacecraft with the rover on its way were the most routine part of the mission. For decades NASA has specialized in space launches, drawing on some of the brightest minds on the planet to determine what it takes to bring a spacecraft to the stars.

Planning the rover’s trip to the red planet (Mars’s nickname, due to its color)—a voyage lasting about 36 weeks at maximum cruise velocity—was also not exactly a new challenge for engineers working on the MSL mission. NASA had already landed two rovers, named “Spirit” and “Opportunity,” on the surface of the red planet. Based on the principles of astronomy, the launch engineers at JPL had very precise requirements for making the journey from Earth to Mars.

The key to these requirements was an understanding of orbits. Although Mars is significantly farther from the sun than Earth, both planets orbit the same star. Their distance from each other changes during each cycle, but Earth comes into alignment with Mars once every 26 months—“lapping” it in a perpetual race around the sun. Observing this pattern, astronomers can work with engineers to pinpoint the optimal month, day, and time for a spacecraft to leave Earth on a speedy one‐way trip.

Drawing on centuries of knowledge of the laws of physics, scientists designed rockets and a spacecraft to accommodate Curiosity. Years of calculation, construction, careful planning and computer modeling resulted in a vessel that cruised purposefully through space, reaching the orbit of Mars at just the right time to attempt a landing.

Through it all, the margin for error was nearly non‐existent. The movement of interplanetary bodies in space is much more demanding than the movement of cars on a highway, or even airplanes in the stratosphere. Miscalculating a vector or failing to account for any aspect of the orbits could lead to a $2 billion failure.

Fortunately, NASA had taken on this challenge before. Its engineers had both the experience and the tenacity to succeed again. What came after the launch was different story.

The Landing Spirit and Opportunity, the two NASA rovers that landed on Mars in 2004, used a combination of parachutes, rockets, and hi‐tech airbags to protect themselves. Much like launch and spaceflight, each step of the landing sequence was planned and simulated to the very last detail. Learning from a prior Mars mission, EDL engineers were able to recreate some of the same maneuvers used in that sequence.

Unfortunately, the specific requirements of MSL made it difficult to depend on past experience. While NASA had constructed the biggest supersonic parachute ever made, parachuting was far from enough. Since the atmosphere of Mars is 100 times thinner than the atmosphere of Earth, the parachute alone could not reduce the speed of descent past 200 miles per hour—a breakneck speed that would surely damage Curiosity upon landing.

Curiosity outweighed any earlier rover and contained over 150 pounds of sensitive scientific devices, so an airbag solution was ruled out. Instead, EDL engineers designed a maneuver that would allow the entry capsule to turn sharply and activate powerful rockets to finish the job. Once this maneuver was complete, the capsule could attempt a vertical landing.

Successfully executing the switch from a parachute entry to a controlled, rocketfueled descent was a feat that could have gone wrong at any moment. Still, even this was not enough to succeed. Once the parachute was cut, and a full radar system was online to guide Curiosity to the surface, the force from the rockets could kick up so much dust that the dust itself would damage the rover.

Eternally thinking one step ahead, EDL engineers designed a device called a “sky crane” to complete the final step of the landing sequence. When the sky crane was 20 feet above Martian soil, it lowered Curiosity onto the surface with a set of cables.

Moving from 13,000 miles per hour to zero miles per hour in just seven minutes, Curiosity finally touched down. The capsule, with all rockets still firing, blasted back into the sky and crash‐landed elsewhere on the planet. The landing was a success.

The Ongoing Mission MSL is the latest of NASA’s attempts to learn more about Mars. The most popular inquiry is whether Mars may have, at any point in its long history, supported life as we know it. The search for these signs, however, is one piece of a much greater picture.

The mission has eight scientific objectives, each one broken into specific goals and all coming together to form a more detailed understanding of all things Mars. Curiosity, a rover the size of a station wagon, contains advanced instruments that will help it probe, sample, record, and analyze its way through Martian terrain. Collecting evidence on the biological, geological, chemical, and radiological profile of the red planet will prepare NASA for the next space flight to Mars. Another rover mission, building on the work of Curiosity, is planned to launch in 2020.

Ultimately, scientists hope to learn enough about Mars to bring human beings to the surface for a manned research mission. Some, working with entrepreneur Elon Musk, are even devising a plan to colonize the planet just one decade later. Skeptics debate whether or not such a seemingly outrageous idea could ever be made into reality.

Looking back at NASA’s solutions to the great technical challenge of the Curiosity landing, it’s hard to feel too skeptical about humankind’s ability to reach for the stars.

Which sentence best expresses the main idea of the selection --

• The landing presented problems that could not be compared directly to anything done before.

• …thanks to the rigorous work of hundreds of engineers, NASA ended up making a new mark on Mars.

• Drawing on centuries of knowledge of the laws of physics, scientists designed rocke3ts and a spacecraft to accommodate Curiosity.

• Ultimately, scientists hope to learn enough about Mars to bring human beings to the surface for a manned research mission.

“Seven Minutes of Terror,” Eight Years of Ingenuity“Sometimes when we look at it, it looks crazy,” remarked Adam Steltzner, an engineer who works for the National Aeronautics and Space Administration— known more commonly to the world as NASA. “It is the result of reasoned engineering thought. But it still looks crazy.”

In a video story entitled “Seven Minutes of Terror,” Steltzner was joined on camera by an eloquent cast of entry‐descent‐landing engineers (or “EDL Engineers”). Working from the Jet Propulsion Laboratory (JPL) in California, their team introduced the world to one of the most daring, inventive feats of engineering the world had ever witnessed: the pinpoint landing of NASA’s Curiosity rover on Mars.

The seven minutes explored in that story—and experienced by the world in early August 2012—took place after seven years of engineering, one year of space flight, and countless hours of collaboration on the perfect landing. Dubbed the Mars Science Laboratory (“MSL”), this mission brought together more than 7,000 people, working in organizations from all over the world, to accomplish its goals. Split into two parts, the launch and the landing, MSL is one of the greatest technological accomplishments of human history.

The most impressive thing about MSL is that no mission this ambitious had ever been attempted in the past. The landing presented problems that could not be compared directly to anything done before. But thanks to the rigorous work of hundreds of engineers, NASA ended up making a new mark on Mars.

The Launch The MSL launch took place on November 26, 2011. Blasting from the Earth at a speed of 12,582 miles per hour, the rockets that broke free of Earth’s orbit and sent the Mars‐bound spacecraft with the rover on its way were the most routine part of the mission. For decades NASA has specialized in space launches, drawing on some of the brightest minds on the planet to determine what it takes to bring a spacecraft to the stars.

Planning the rover’s trip to the red planet (Mars’s nickname, due to its color)—a voyage lasting about 36 weeks at maximum cruise velocity—was also not exactly a new challenge for engineers working on the MSL mission. NASA had already landed two rovers, named “Spirit” and “Opportunity,” on the surface of the red planet. Based on the principles of astronomy, the launch engineers at JPL had very precise requirements for making the journey from Earth to Mars.

The key to these requirements was an understanding of orbits. Although Mars is significantly farther from the sun than Earth, both planets orbit the same star. Their distance from each other changes during each cycle, but Earth comes into alignment with Mars once every 26 months—“lapping” it in a perpetual race around the sun. Observing this pattern, astronomers can work with engineers to pinpoint the optimal month, day, and time for a spacecraft to leave Earth on a speedy one‐way trip.

Drawing on centuries of knowledge of the laws of physics, scientists designed rockets and a spacecraft to accommodate Curiosity. Years of calculation, construction, careful planning and computer modeling resulted in a vessel that cruised purposefully through space, reaching the orbit of Mars at just the right time to attempt a landing.

Through it all, the margin for error was nearly non‐existent. The movement of interplanetary bodies in space is much more demanding than the movement of cars on a highway, or even airplanes in the stratosphere. Miscalculating a vector or failing to account for any aspect of the orbits could lead to a $2 billion failure.

Fortunately, NASA had taken on this challenge before. Its engineers had both the experience and the tenacity to succeed again. What came after the launch was different story.

The Landing Spirit and Opportunity, the two NASA rovers that landed on Mars in 2004, used a combination of parachutes, rockets, and hi‐tech airbags to protect themselves. Much like launch and spaceflight, each step of the landing sequence was planned and simulated to the very last detail. Learning from a prior Mars mission, EDL engineers were able to recreate some of the same maneuvers used in that sequence.

Unfortunately, the specific requirements of MSL made it difficult to depend on past experience. While NASA had constructed the biggest supersonic parachute ever made, parachuting was far from enough. Since the atmosphere of Mars is 100 times thinner than the atmosphere of Earth, the parachute alone could not reduce the speed of descent past 200 miles per hour—a breakneck speed that would surely damage Curiosity upon landing.

Curiosity outweighed any earlier rover and contained over 150 pounds of sensitive scientific devices, so an airbag solution was ruled out. Instead, EDL engineers designed a maneuver that would allow the entry capsule to turn sharply and activate powerful rockets to finish the job. Once this maneuver was complete, the capsule could attempt a vertical landing.

Successfully executing the switch from a parachute entry to a controlled, rocketfueled descent was a feat that could have gone wrong at any moment. Still, even this was not enough to succeed. Once the parachute was cut, and a full radar system was online to guide Curiosity to the surface, the force from the rockets could kick up so much dust that the dust itself would damage the rover.

Eternally thinking one step ahead, EDL engineers designed a device called a “sky crane” to complete the final step of the landing sequence. When the sky crane was 20 feet above Martian soil, it lowered Curiosity onto the surface with a set of cables.

Moving from 13,000 miles per hour to zero miles per hour in just seven minutes, Curiosity finally touched down. The capsule, with all rockets still firing, blasted back into the sky and crash‐landed elsewhere on the planet. The landing was a success.

The Ongoing Mission MSL is the latest of NASA’s attempts to learn more about Mars. The most popular inquiry is whether Mars may have, at any point in its long history, supported life as we know it. The search for these signs, however, is one piece of a much greater picture.

The mission has eight scientific objectives, each one broken into specific goals and all coming together to form a more detailed understanding of all things Mars. Curiosity, a rover the size of a station wagon, contains advanced instruments that will help it probe, sample, record, and analyze its way through Martian terrain. Collecting evidence on the biological, geological, chemical, and radiological profile of the red planet will prepare NASA for the next space flight to Mars. Another rover mission, building on the work of Curiosity, is planned to launch in 2020.

Ultimately, scientists hope to learn enough about Mars to bring human beings to the surface for a manned research mission. Some, working with entrepreneur Elon Musk, are even devising a plan to colonize the planet just one decade later. Skeptics debate whether or not such a seemingly outrageous idea could ever be made into reality.

Looking back at NASA’s solutions to the great technical challenge of the Curiosity landing, it’s hard to feel too skeptical about humankind’s ability to reach for the stars.

1. Read the following sentence: “The mission had eight scientific objectives, each one broken into specific goals and all coming together to form a more detailed understanding of all things Mars.”

What does the word “mission” mean?

• an important assignment carried out for political, religious, or commercial purposes, typically involving travel

• the vocation or calling of a religious organization to go out into the world and spread its faith

• a strongly felt aim, ambition, or calling

• an important task or duty that is assigned, allotted, or self-imposed

“Seven Minutes of Terror,” Eight Years of Ingenuity“Sometimes when we look at it, it looks crazy,” remarked Adam Steltzner, an engineer who works for the National Aeronautics and Space Administration— known more commonly to the world as NASA. “It is the result of reasoned engineering thought. But it still looks crazy.”

In a video story entitled “Seven Minutes of Terror,” Steltzner was joined on camera by an eloquent cast of entry‐descent‐landing engineers (or “EDL Engineers”). Working from the Jet Propulsion Laboratory (JPL) in California, their team introduced the world to one of the most daring, inventive feats of engineering the world had ever witnessed: the pinpoint landing of NASA’s Curiosity rover on Mars.

The seven minutes explored in that story—and experienced by the world in early August 2012—took place after seven years of engineering, one year of space flight, and countless hours of collaboration on the perfect landing. Dubbed the Mars Science Laboratory (“MSL”), this mission brought together more than 7,000 people, working in organizations from all over the world, to accomplish its goals. Split into two parts, the launch and the landing, MSL is one of the greatest technological accomplishments of human history.

The most impressive thing about MSL is that no mission this ambitious had ever been attempted in the past. The landing presented problems that could not be compared directly to anything done before. But thanks to the rigorous work of hundreds of engineers, NASA ended up making a new mark on Mars.

The Launch The MSL launch took place on November 26, 2011. Blasting from the Earth at a speed of 12,582 miles per hour, the rockets that broke free of Earth’s orbit and sent the Mars‐bound spacecraft with the rover on its way were the most routine part of the mission. For decades NASA has specialized in space launches, drawing on some of the brightest minds on the planet to determine what it takes to bring a spacecraft to the stars.

Planning the rover’s trip to the red planet (Mars’s nickname, due to its color)—a voyage lasting about 36 weeks at maximum cruise velocity—was also not exactly a new challenge for engineers working on the MSL mission. NASA had already landed two rovers, named “Spirit” and “Opportunity,” on the surface of the red planet. Based on the principles of astronomy, the launch engineers at JPL had very precise requirements for making the journey from Earth to Mars.

The key to these requirements was an understanding of orbits. Although Mars is significantly farther from the sun than Earth, both planets orbit the same star. Their distance from each other changes during each cycle, but Earth comes into alignment with Mars once every 26 months—“lapping” it in a perpetual race around the sun. Observing this pattern, astronomers can work with engineers to pinpoint the optimal month, day, and time for a spacecraft to leave Earth on a speedy one‐way trip.

Drawing on centuries of knowledge of the laws of physics, scientists designed rockets and a spacecraft to accommodate Curiosity. Years of calculation, construction, careful planning and computer modeling resulted in a vessel that cruised purposefully through space, reaching the orbit of Mars at just the right time to attempt a landing.

Through it all, the margin for error was nearly non‐existent. The movement of interplanetary bodies in space is much more demanding than the movement of cars on a highway, or even airplanes in the stratosphere. Miscalculating a vector or failing to account for any aspect of the orbits could lead to a $2 billion failure.

Fortunately, NASA had taken on this challenge before. Its engineers had both the experience and the tenacity to succeed again. What came after the launch was different story.

The Landing Spirit and Opportunity, the two NASA rovers that landed on Mars in 2004, used a combination of parachutes, rockets, and hi‐tech airbags to protect themselves. Much like launch and spaceflight, each step of the landing sequence was planned and simulated to the very last detail. Learning from a prior Mars mission, EDL engineers were able to recreate some of the same maneuvers used in that sequence.

Unfortunately, the specific requirements of MSL made it difficult to depend on past experience. While NASA had constructed the biggest supersonic parachute ever made, parachuting was far from enough. Since the atmosphere of Mars is 100 times thinner than the atmosphere of Earth, the parachute alone could not reduce the speed of descent past 200 miles per hour—a breakneck speed that would surely damage Curiosity upon landing.

Curiosity outweighed any earlier rover and contained over 150 pounds of sensitive scientific devices, so an airbag solution was ruled out. Instead, EDL engineers designed a maneuver that would allow the entry capsule to turn sharply and activate powerful rockets to finish the job. Once this maneuver was complete, the capsule could attempt a vertical landing.

Successfully executing the switch from a parachute entry to a controlled, rocketfueled descent was a feat that could have gone wrong at any moment. Still, even this was not enough to succeed. Once the parachute was cut, and a full radar system was online to guide Curiosity to the surface, the force from the rockets could kick up so much dust that the dust itself would damage the rover.

Eternally thinking one step ahead, EDL engineers designed a device called a “sky crane” to complete the final step of the landing sequence. When the sky crane was 20 feet above Martian soil, it lowered Curiosity onto the surface with a set of cables.

Moving from 13,000 miles per hour to zero miles per hour in just seven minutes, Curiosity finally touched down. The capsule, with all rockets still firing, blasted back into the sky and crash‐landed elsewhere on the planet. The landing was a success.

The Ongoing Mission MSL is the latest of NASA’s attempts to learn more about Mars. The most popular inquiry is whether Mars may have, at any point in its long history, supported life as we know it. The search for these signs, however, is one piece of a much greater picture.

The mission has eight scientific objectives, each one broken into specific goals and all coming together to form a more detailed understanding of all things Mars. Curiosity, a rover the size of a station wagon, contains advanced instruments that will help it probe, sample, record, and analyze its way through Martian terrain. Collecting evidence on the biological, geological, chemical, and radiological profile of the red planet will prepare NASA for the next space flight to Mars. Another rover mission, building on the work of Curiosity, is planned to launch in 2020.

Ultimately, scientists hope to learn enough about Mars to bring human beings to the surface for a manned research mission. Some, working with entrepreneur Elon Musk, are even devising a plan to colonize the planet just one decade later. Skeptics debate whether or not such a seemingly outrageous idea could ever be made into reality.

Looking back at NASA’s solutions to the great technical challenge of the Curiosity landing, it’s hard to feel too skeptical about humankind’s ability to reach for the stars.

The author wrote this selection most likely to

• Describe the inventiveness required for the pinpoint landing of Curiosity rover on Mars.

• Explain how the cost didn’t leave room for error.

• Convince the reader that life on Mars is a possibility.

• Demonstrate the ways scientists and engineers play a role space exploration.

“Seven Minutes of Terror,” Eight Years of Ingenuity“Sometimes when we look at it, it looks crazy,” remarked Adam Steltzner, an engineer who works for the National Aeronautics and Space Administration— known more commonly to the world as NASA. “It is the result of reasoned engineering thought. But it still looks crazy.”

In a video story entitled “Seven Minutes of Terror,” Steltzner was joined on camera by an eloquent cast of entry‐descent‐landing engineers (or “EDL Engineers”). Working from the Jet Propulsion Laboratory (JPL) in California, their team introduced the world to one of the most daring, inventive feats of engineering the world had ever witnessed: the pinpoint landing of NASA’s Curiosity rover on Mars.

The seven minutes explored in that story—and experienced by the world in early August 2012—took place after seven years of engineering, one year of space flight, and countless hours of collaboration on the perfect landing. Dubbed the Mars Science Laboratory (“MSL”), this mission brought together more than 7,000 people, working in organizations from all over the world, to accomplish its goals. Split into two parts, the launch and the landing, MSL is one of the greatest technological accomplishments of human history.

The most impressive thing about MSL is that no mission this ambitious had ever been attempted in the past. The landing presented problems that could not be compared directly to anything done before. But thanks to the rigorous work of hundreds of engineers, NASA ended up making a new mark on Mars.

The Launch The MSL launch took place on November 26, 2011. Blasting from the Earth at a speed of 12,582 miles per hour, the rockets that broke free of Earth’s orbit and sent the Mars‐bound spacecraft with the rover on its way were the most routine part of the mission. For decades NASA has specialized in space launches, drawing on some of the brightest minds on the planet to determine what it takes to bring a spacecraft to the stars.

Planning the rover’s trip to the red planet (Mars’s nickname, due to its color)—a voyage lasting about 36 weeks at maximum cruise velocity—was also not exactly a new challenge for engineers working on the MSL mission. NASA had already landed two rovers, named “Spirit” and “Opportunity,” on the surface of the red planet. Based on the principles of astronomy, the launch engineers at JPL had very precise requirements for making the journey from Earth to Mars.

The key to these requirements was an understanding of orbits. Although Mars is significantly farther from the sun than Earth, both planets orbit the same star. Their distance from each other changes during each cycle, but Earth comes into alignment with Mars once every 26 months—“lapping” it in a perpetual race around the sun. Observing this pattern, astronomers can work with engineers to pinpoint the optimal month, day, and time for a spacecraft to leave Earth on a speedy one‐way trip.

Drawing on centuries of knowledge of the laws of physics, scientists designed rockets and a spacecraft to accommodate Curiosity. Years of calculation, construction, careful planning and computer modeling resulted in a vessel that cruised purposefully through space, reaching the orbit of Mars at just the right time to attempt a landing.

Through it all, the margin for error was nearly non‐existent. The movement of interplanetary bodies in space is much more demanding than the movement of cars on a highway, or even airplanes in the stratosphere. Miscalculating a vector or failing to account for any aspect of the orbits could lead to a $2 billion failure.

Fortunately, NASA had taken on this challenge before. Its engineers had both the experience and the tenacity to succeed again. What came after the launch was different story.

The Landing Spirit and Opportunity, the two NASA rovers that landed on Mars in 2004, used a combination of parachutes, rockets, and hi‐tech airbags to protect themselves. Much like launch and spaceflight, each step of the landing sequence was planned and simulated to the very last detail. Learning from a prior Mars mission, EDL engineers were able to recreate some of the same maneuvers used in that sequence.

Unfortunately, the specific requirements of MSL made it difficult to depend on past experience. While NASA had constructed the biggest supersonic parachute ever made, parachuting was far from enough. Since the atmosphere of Mars is 100 times thinner than the atmosphere of Earth, the parachute alone could not reduce the speed of descent past 200 miles per hour—a breakneck speed that would surely damage Curiosity upon landing.

Curiosity outweighed any earlier rover and contained over 150 pounds of sensitive scientific devices, so an airbag solution was ruled out. Instead, EDL engineers designed a maneuver that would allow the entry capsule to turn sharply and activate powerful rockets to finish the job. Once this maneuver was complete, the capsule could attempt a vertical landing.

Successfully executing the switch from a parachute entry to a controlled, rocketfueled descent was a feat that could have gone wrong at any moment. Still, even this was not enough to succeed. Once the parachute was cut, and a full radar system was online to guide Curiosity to the surface, the force from the rockets could kick up so much dust that the dust itself would damage the rover.

Eternally thinking one step ahead, EDL engineers designed a device called a “sky crane” to complete the final step of the landing sequence. When the sky crane was 20 feet above Martian soil, it lowered Curiosity onto the surface with a set of cables.

Moving from 13,000 miles per hour to zero miles per hour in just seven minutes, Curiosity finally touched down. The capsule, with all rockets still firing, blasted back into the sky and crash‐landed elsewhere on the planet. The landing was a success.

The Ongoing Mission MSL is the latest of NASA’s attempts to learn more about Mars. The most popular inquiry is whether Mars may have, at any point in its long history, supported life as we know it. The search for these signs, however, is one piece of a much greater picture.

The mission has eight scientific objectives, each one broken into specific goals and all coming together to form a more detailed understanding of all things Mars. Curiosity, a rover the size of a station wagon, contains advanced instruments that will help it probe, sample, record, and analyze its way through Martian terrain. Collecting evidence on the biological, geological, chemical, and radiological profile of the red planet will prepare NASA for the next space flight to Mars. Another rover mission, building on the work of Curiosity, is planned to launch in 2020.

Ultimately, scientists hope to learn enough about Mars to bring human beings to the surface for a manned research mission. Some, working with entrepreneur Elon Musk, are even devising a plan to colonize the planet just one decade later. Skeptics debate whether or not such a seemingly outrageous idea could ever be made into reality.

Looking back at NASA’s solutions to the great technical challenge of the Curiosity landing, it’s hard to feel too skeptical about humankind’s ability to reach for the stars.

1. Read the following sentence: “The mission had eight scientific objectives, each one broken into specific goals and all coming together to form a more detailed understanding of all things Mars.”

Which detail is best supported by the photograph?

• Miscalculating a vector or failing to account for an aspect of the orbits could lead to a $2 billion failure.

• When the “sky crane” was 20 feet above Martian soil, it lowered Curiosity on the surface with a set of cables.

• Moving from 13,000 miles per hour to zero miles per hour in just seven minutes, Curiosity finally touched down.

• The capsule, with all rockets still firing, blasted back into the sky and crash-landed elsewhere on the planet.

What are the risks of dust and sand on Mars?All equipment that will be sent to Mars must be built specifically to withstand the conditions there. The environment of Mars contains dust that is much finer than that found on Earth. While the exact effects of this fine dust on technical hardware and equipment are not fully known, it is not impossible to engineer equipment that can handle the dust. The NASA rovers Spirit and Opportunity were designed to operate for a minimum of 90 days, but have exceeded their target lifespans substantially. Spirit lasted about 1900 days. Opportunity is still driving around and investigating Mars since January 2004.

It is unknown how the fine Mars dust might affect humans, should they be exposed to it. However, the astronauts will only go outside in their fully-enclosed Mars suits, and inside the habitat, the air will be filtered to remove dust.

StormsMars has a very thin atmosphere, about 1% of Earth’s atmosphere. Because of this, hurricane forces on Mars feel like a gentle breezes on Earth. The problem of a storm is not that it will push you over or destroy material, the problem is that Mars is extremely 'dusty'.

Dust stormsMars has dust storms that can cover the entire planet for a whole month. This does not happen often, but smaller dust storms are quite common.

During dust storms the power output of the solar panels will decrease. While direct lighting to the panels is reduced significantly, there is still sufficient lighting from indirect light to power the crucial life support systems of the settlement. Water and oxygen production will be turned off and instead stored water and oxygen will be consumed. Lighting to the greenhouse will be lowered and other non-essential systems will be turned off.

Power during a dust stormMars One has designed the Mars mission to fully exploit, wherever possible, solar power generation. The mission design makes use of ‘thin film’ solar panels, which are extremely light and can be easily transported.

Solar power however has a few disadvantages: during night time, the energy must come from batteries; and during dust storms, the solar panels will yield less energy.

The solar panel system used by Mars One will deliver enough energy to power all critical systems during a dust storm.

Non-critical systems however will be shut down or restricted, to save energy:

Oxygen and water will come primarily from the storage tanks (not from powered extraction) Dirty water will be stored (for later recycling, when full power is available) Oxygen from the storage tanks will be consumed Greenhouse lighting will be dimmed EVAs will be limited to emergency repairs Rover operation will be limited

The astronauts will have enough water stored for 15 days of normal water usage, and for 150 days if usage is limited. The oxygen storage tanks will contain enough oxygen for 60 days. Because electrical power is so critical for the survival of the crew, extra safety margins will be built into the power usage profiles for dust storms.

When required, rovers can be used to remove dust from the solar panels.

Other methods of power generation that could potentially be used on Mars are not yet available as existing technology. The most commonly referred to alternative is nuclear power. While nuclear power is a commonly used technology on Earth, a nuclear power generator in the size that would be needed for a human settlement on Mars doesn't exist yet.

From the organization of the section “What are the risks of dust and sand on mars,” the reader can conclude that:

• The equipment on mars will be engineered to withstand the harsh wind and dust storms.

• Dust storms will affect the solar power operations.

• Noncritical systems will not be shut down during dust storms.

• In the event of a solar power failure, a nuclear power generator will take over the power generation.

What will the astronauts do on Mars?During their working hours, our astronauts will be busy performing three main tasks: construction, maintenance and research. Besides work, they will also have time to relax.

ConstructionConstruction involves working on the settlement. The first crew in particular will need to devote a lot of time to the settlement, to make their new home into a comfortable place to live. They will install the corridors between the landers, they will deploy extra solar panels, and they will install equipment, such as greenhouses, inside the habitat. They will spend time on the crops and food preparation. They will also prepare the hardware for the second crew: the second crew hardware will be delivered with the first crew astronauts.

As soon as possible, Mars One will try to supply the settlement with methodologies to produce habitable volume from mostly Martian materials, in order to significantly expand the settlement. Our goal is to enable them to construct a space 10 meters wide by 50 meters long. This will be a spacious environment in which to live, where they can also grow trees. Such a large living volume will make Mars a much nicer place to live.

MaintenanceMaintenance will be crucial to ensure long-term functionality of all systems. The astronauts lives depend on the technology present in the settlement. All these systems need to be checked and maintained regularly.

ResearchResearch is also an important part of work on Mars, especially when the settlement is fully operational. What is the history of Mars? Did Mars have a long wet period, or just a few wet years every now and then? When did the dramatic climate change take place? Is there life on Mars now? The astronauts will do their own research, but will also collect data for other researchers, and transmit it to Earth.

Leisure and personal timeOur astronauts will also find time to relax. They can do most of the indoor activities that people can do on Earth: read, play games, write, paint, work out in the gym, watch TV, use the Internet, contact friends at home and so on.

There will be some communication and media limitations, due to the distance between Earth and Mars, resulting in time delays: they will have to request the movies or news broadcasts they want to see in advance. If an astronaut would like to watch the Super Bowl, he or she can request it, and it would be uploaded to the server on Mars. There will always be a time delay of at least three minutes, so the people on Mars will know who won a few minutes after the people on Earth. Hopefully this slight delay will not spoil their enjoyment of our ‘Earth sports’.

Easy Internet access will be limited to their preferred sites that are constantly updated on the local Mars web server. Other websites will take between 6 and 45 minutes to appear on their screen - first 3-22 minutes for your click to reach Earth, and then another 3-22 minutes for the website data to reach Mars. Contacting friends at home is possible by video, voice or text message (e-mail, WhatsApp, sms), but real time dialogue is not possible, because of the time delay.

The descriptive organization of the section titled, “What will astronauts do on mars” helps the reader understand:

• How astronauts will be able to watch the Super Bowl from mars.

• How astronauts will expand the settlement on mars.

• How astronauts will maintain and check systems that their lives depend on.

• The main ways astronauts will spend their time on mars.

How long does it take to travel to Mars?The trip takes around seven months; a bit longer than astronauts currently stay on the International Space Station.

The precise duration of each journey depends on when it is taken. Because both Mars and Earth's orbits are not perfectly circular, the time it takes to travel between them varies from six to eight months.

How to determine the dates of departure and arrivalThe exact dates and years in which Mars One plans to execute the various stages of the plan were chosen for the beneficial astronomical position of Earth and Mars. When determining the course to Mars, the maximum travel time for the astronauts is very important.

The most efficient route to take from Earth’s orbit to that of Mars is called the ‘Hohmann Transfer Orbit’ (see: illustration). The illustration shows a simplification of the process, as both Earth and Mars’ orbits are not perfect circle.

The organizational pattern of the section “How Long to Travel to Mars?” is intended to…

• highlight the problems that will be faced on the journey to Mars and solutions to those problems

• describe the how long the trip to Mars will take and how travel dates are determined

• emphasize the similarities and differences of Earth versus Mars

• to explain the steps they will follow on the journey to Mars from Earth

How safe is the journey?The trip to Mars cannot be called risk free. Like any venture in any means of travel, there are always things that could go wrong. In the case of Mars One, the following risks are conceivable:

Accident(s) during launch Vital components could malfunction during the journey there A number of issues might present themselves when entering Mars' atmosphere There could be problems when landing

Mars One will take every possible precaution to make sure the mission is as safe as can be:

The rocket will be tested unmanned dozens of times before the astronauts so much as see it. Mars One uses technology that has been operating on the International Space Station for years, and have already planned for important components to be meticulously tested before use. By the time the astronauts start their journey, the process of entering Mars' atmosphere will already have been performed several times by unmanned capsules.

Although traveling to Mars will evidently bring risks, if you were to compare our mission to the first Moon mission in 1969, it quickly becomes apparent that this mission is much safer. At the time of Apollo 11, there was a great deal of pressure to rush proceedings, and was therefore never properly tested. For example, the lunar lander hadn't even been tested once.

The section “How safe is the journey?” is organized in a way that shows…

• that traveling aboard Mars One is completely safe and there is no risk involved.

• a chronological history of space exploration, beginning with the first Moon mission in 1969.

• the problems that could arise on the journey to Mars and the precautions that Mars One will take to ensure that the mission is as safe as can be.

• A step by step explanation of the process of testing rockets.

How safe is the journey?The trip to Mars cannot be called risk free. Like any venture in any means of travel, there are always things that could go wrong. In the case of Mars One, the following risks are conceivable:

Accident(s) during launch Vital components could malfunction during the journey there A number of issues might present themselves when entering Mars' atmosphere There could be problems when landing

Mars One will take every possible precaution to make sure the mission is as safe as can be:

The rocket will be tested unmanned dozens of times before the astronauts so much as see it. Mars One uses technology that has been operating on the International Space Station for years, and have already planned for important components to be meticulously tested before use. By the time the astronauts start their journey, the process of entering Mars' atmosphere will already have been performed several times by unmanned capsules.

Although traveling to Mars will evidently bring risks, if you were to compare our mission to the first Moon mission in 1969, it quickly becomes apparent that this mission is much safer. At the time of Apollo 11, there was a great deal of pressure to rush proceedings, and was therefore never properly tested. For example, the lunar lander hadn't even been tested once.

The author organized the last paragraph in the section “How safe is the journey?” for the purpose of…

• showing that Mars One is safer than the first lunar Mission in 1969 because of increased testing and added precautions.

• providing a detailed description of all of the mistakes that were made aboard the Apollo 11 mission.

• discussing the numerous risks that are involved in space travel.

• explaining why there was so much pressure to rush proceedings and not properly test the Apollo 11.