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Project Apollo was an enormous challenge for the National Aeronautics and Space Administration, or NASA. Hundreds of thousands of people from across the country needed to work together on the different parts of this challenge. They needed to figure out how to safely launch a crew from Earth, land on the Moon, and return the crew safely to Earth. To successfully complete each part of this challenge, they needed to solve many individual engineering problems.

To solve problems, engineers often use the engineering-design process. The diagram below shows one version of the engineering-design process. In the diagram, there are six steps that engineers can work through when solving problems. Often an individual or a team will move clockwise through the steps in the diagram beginning with the step at the top (Identify the problem).

But, engineers can decide to work through the steps in any order based on the situation. They may even repeat or skip steps as needed. So, the diagram has lines that connect each step to every other step in the process. These lines represent the many possible paths that the process may follow.

In the engineering-design process diagram, what do the lines connecting the six steps show?

One of the first problems that Project Apollo engineers needed to solve was to figure out the best way to send astronauts to the Moon. This was a tough problem that no one had ever solved before, so several groups of engineers brainstormed ideas. While brainstorming, they had to consider several constraints, including how long it would take to design, build, and test the spacecraft, and how much it would cost.

Engineers came up with many possible solutions to the problem. The two best solutions were called the Earth Orbit Rendezvous method and the Lunar Orbit Rendezvous method. To rendezvous means to meet at a specific time and place. The word lunar means relating to the Moon. In both solutions, two separate sections of the spacecraft had to rendezvous in space and dock, or connect together. In the Earth Orbit Rendezvous method, the sections would meet while in orbit around Earth. In the Lunar Orbit Rendezvous method, the sections would meet while in orbit around the Moon.

Both solutions had advantages and disadvantages. To help decide on a solution, engineers often create and test prototypes or models of the proposed solutions. When evaluating the proposed solutions to send astronauts to the Moon, engineers did not have the time or the money to build and test physical prototypes of the different spacecraft that would be used in each solution.

Instead of building physical models, engineers made mathematical models. The mathematical models, or mathematical prototypes, could be used to make various calculations for each method. The engineers used these calculations to evaluate each solution and determine how well each one met the constraints.

Which of the following statements are true about the prototypes used to decide between the Earth Orbit Rendezvous and Lunar Orbit Rendezvous methods? Select all that apply.

One of the first problems that engineers solved was figuring out whether the Earth Orbit Rendezvous or the Lunar Orbit Rendezvous was the better method for going to the Moon. Using information from mathematical prototypes, NASA chose the Lunar Orbit Rendezvous method. The Lunar Orbit Rendezvous method would require fewer rocket launches, less fuel, and a smaller and lighter spacecraft than the Earth Orbit Rendezvous method. These advantages would allow the engineers to build the spacecraft in less time and to spend less money.

Once the decision was made to use the Lunar Orbit Rendezvous method, engineers could begin designing the spacecraft and solving related problems. They could not start designing sooner because the spacecraft constraints for the Lunar Orbit Rendezvous method were different than those for the Earth Orbit Rendezvous method. For example, the lunar mission vehicle for the Earth Orbit Rendezvous method would need to house the astronauts for the entire journey to the Moon and back to Earth. But the lunar module for the Lunar Orbit Rendezvous method would not need to carry astronauts for that long.

Why was it important to decide between the Lunar Orbit Rendezvous method and the Earth Orbit Rendezvous method near the beginning of Project Apollo?

Project Apollo was an enormous challenge for the National Aeronautics and Space Administration or NASA. Hundreds of thousands of people from across the country needed to work together on the different parts of this challenge. They needed to figure out how to safely launch a crew from Earth, land on the Moon, and return the crew safely back to Earth. To successfully complete each part of this challenge, many individual engineering problems needed to be solved.

To solve problems, engineers often use the engineering design process. The diagram below shows one version of the engineering design process. In the diagram, there are six steps that engineers can work through when solving problems. Often an individual or a team will move clockwise through the steps in the diagram beginning with the step at the top (Identify the problem).

But, engineers can decide to work through the steps in any order based on the situation. They may even repeat or skip steps as needed. So, the diagram has lines that connect each step to every other step in the process. These lines represent the many possible paths that the process may follow.

Project Apollo presented many engineering problems. When finding a good solution to a problem, engineers must identify and work within a set of constraints. Constraints are things that limit the possible solutions to a problem.

Project Apollo had three key constraints: time, safety, and cost. President Kennedy set 1970 as the target deadline for landing a person on the Moon. He also specified that the astronauts must return safely to Earth. The project had a budget that specified how much money could be spent. Solutions to any of the Project Apollo problems had to work within these constraints.

In engineering problems, some constraints may be prioritized, or treated as more important than other constraints. For Project Apollo, time and safety were prioritized over cost.

Which of the following statements describes how the constraints of Project Apollo were prioritized?

Once NASA decided to use the Lunar Orbit Rendezvous method to get to the Moon, engineers could start working on the rocket that would launch the spacecraft from Earth. The rocket needed to be powerful enough to send the spacecraft all the way to the Moon.

To accomplish this, engineers modified a rocket already in development for another NASA project. This new version was called the Saturn V rocket. The V is a Roman numeral representing 5, so the name is pronounced "Saturn five rocket."

A diagram of the Saturn V rocket and spacecraft is shown below. The Saturn V rocket is made of three main parts or stages. Each stage provided power at different times during the flight to the Moon. The spacecraft is where the astronauts would live during the trip to the Moon.

Engineers built both mathematical prototypes and physical prototypes to help refine and test their design of the Saturn V rocket. They built mathematical prototypes first because those are usually quicker and less expensive to build than physical prototypes.

The mathematical prototypes helped engineers refine their designs. For example, engineers used the mathematical prototypes to calculate how much power the engines would need to produce to send the spacecraft to the Moon.

After using the mathematical prototypes to refine the designs, engineers could build life-size physical prototypes of the Saturn V rocket. The physical prototypes could be launched from Earth to test how well they worked. Engineers wanted to test the design without putting people in danger, so the prototypes were launched without astronauts inside.

Which of the following statements about the Saturn V rocket prototypes are true? Select all that apply.

Once the physical prototypes of the Saturn V rocket were built, they were launched without any astronauts aboard. These test flights did not go all the way to the Moon, but they allowed engineers to figure out how each piece of the rocket performed in flight. The picture below shows the launch of the second test flight of a Saturn V rocket.