On the 50th anniversary of Apollo 11’s moon landing, the National Aeronautic and Space Administration (NASA) is setting its sights on returning to the moon, and going far beyond. The Lunar Orbital Platform-Gateway, a crucial outpost for the U.S. mission to relay astronauts to the moon in 2024, has had a slow start, but the initial module is now under contract.

NASA is also working to send astronauts to the moon’s south pole region by 2024, an area thought to have potential for resources beneficial to deep-space exploration.

When Kennedy said “We choose to go to the moon,” in 1962, he wanted it done by the end of the decade. At the time, Project Mercury, NASA’s effort to get an astronaut into orbit, was already under way. But much of the expertise and machinery that would allow humans to walk on the moon did not yet exist.

SPACECRAFT EVOLUTION

The three missions NASA developed to navigate their path to the moon were markedly different in their respective goals, yet each built directly on the successes and failures of the prior. The selection criteria for astronauts changed with the mission, not only in terms of education and technical aspects, but some physical standards as well.

The initial Mercury astronauts were required to be 5 feet 11 inches or shorter, but height requirements for Gemini were relaxed by an inch as the capsules grew — slightly — more spacious. Here’s a look at how the three projects and crew capsules differed.

- Michael Collins
Apollo 11 Command Module Pilot

MOON SHOTS

The Cold War saw the birth of space programs from the Soviet Union, the United States and China. Global tensions spurred quick progress, with respective nations seeing success in space as a way to attain a strategic advantage both on Earth and beyond.

While the Soviets achieved many firsts in space exploration — including the first to launch a man-made object in orbit, the first to put a man and woman in space — the United States was the first country to reach the moon with a crewed mission and the only one to date.

Here’s a look at all the lunar “soft” landings achieved by the Soviet Union, China and the United States.

SOVIET FIRSTS
Eight Landings

The Soviet Union’s Luna program successfully sent the first probe to the moon in 1959, named Luna 2, and with Luna 3 brought back the first images of the far side of the moon ever seen.

Toward the end of the program, the Luna probes had advanced enough to collect and return lunar surface material to Earth. While the program accomplished several technical achievements, the Soviets did not ultimately send a crewed mission to the moon.

CHINESE INNOVATION
Two landings

The Chinese space program was created in 1956 in an effort to keep pace with the Soviets and Americans. The country’s first satellite was launched in 1970 and transmitted China’s national anthem for 28 days.

In 2003, China became the third country to successfully launch a person into space, and has since landed two probes on the moon: the Chang’e-3 on the near side and in 2019 the Chang’e-4 became the first probe to land on the far side of the moon.

Beijing plans to collect samples from the near side of the moon around the end of the year with its Chang’e-5 mission, while another probe will be sent to Mars by 2020.

AMERICA’S SMALL STEP
Six Apollo landings
Five Surveyor landings

On July 20th, 1969, Apollo 11 astronauts Neil Armstrong and Buzz Aldrin touched down on the lunar surface. The pair became the first humans to walk on the moon.

Prior to the Apollo missions, NASA sent Surveyor probes to determine if the lunar terrain was safe for manned landings. Eventually, six crewed Apollo missions reached the surface and most of them landed around the equatorial area on the near side of the moon.

After India’s probe discovered water on the moon’s South Pole in 2008, NASA followed with a probe to gather data on how much and in what concentrations resources may exist. The South Pole is a target for NASA’s lunar landing mission targeted for 2024.

Currently, there is an international effort led by NASA and the European Space agency to build an orbiting lunar station.

While only three countries have successfully landed on the moon, several others have sent missions to explore Earth’s natural satellite.

The Indian space agency is taking its second shot at the moon on July 14, with Chandrayaan-2 orbiting the moon and landing near the South Pole to deploy the Pragyan rover.

12 lesser-known facts about the Apollo 11 mission

LUNAR GATEWAY

Over the next decade, an international consortium of space agencies will produce different parts to build the Lunar Orbital Platform-Gateway, which will provide access to and from the moon’s surface and serve as a refueling station for deep-space missions.

The agencies include NASA, the European Space Agency (ESA), the Canadian Space Agency (CSA), Japan Aerospace Exploration Agency (JAXA), and Roscosmos, Russia’s space agency. Here’s a look at the latest configuration of the Gateway.

The Gateway will follow a six-day halo orbit around the moon, bringing it very close to the surface of the moon while staying in constant communication with Earth. Mission durations are estimated to be around 30-90 days and will have room for four crew members.

NASA believes it can complete the Gateway with payloads from five or six launches, which stands in contrast to the more than 40 launches that were needed for the International Space Station.

In May, the U.S. space agency announced that it has picked space technology company Maxar Technologies Inc as the first contractor to help build its Gateway platform. The firm will develop power, propulsion and communications components for the lunar mobile command and service module.

SOUTHERN EXPOSURE

The lunar south pole has been an area of increased interest since India’s Chandrayaan-1 probe discovered ice in the area more than 10 years ago. A second Indian lunar mission plans to land a rover in the region in September.

NASA and others have set their sights on the moon’s south pole because it's a region believed to hold enough recoverable ice water for use in synthesizing additional rocket fuel as well as for drinking water to sustain astronauts.

Billionaire entrepreneur and Blue Origin founder Jeff Bezos announced during an event in May that his company’s lunar lander, dubbed Blue Moon, is planning to go to the lunar south pole.

Of particular interest is the Shackleton Crater, named after Antarctic explorer Ernest Shackleton. The crater is deeper than the Grand Canyon and, due to the rather small tilt of the moon’s axis, the depths of the crater never see sunlight. The crater’s rim, however, spends almost 90% of the year exposed to direct sunlight.

This extended period of light and presence of water create an appealing environment for a potential moon base. The almost constant sunlight can be collected by solar panels and water could be used to create a breathable atmosphere.

Mining resources on the moon could enable deep-space exploration by greatly reducing the weight of rockets leaving Earth, thus decreasing the cost. U.S. Vice President Mike Pence has said it’s time for the next giant leap for NASA, referencing Neil Armstrong’s famous words.

“That next giant leap is to return American astronauts to the moon within the next five years by any means necessary, and to establish a permanent presence on the moon and prepare to put American astronauts on Mars,” Pence said.

EARTH TO MARS

The moon is about a three-day trip from Earth, but NASA’s eventual target is Mars — and the red planet is exponentially farther away.

Mars takes about twice as long to orbit the sun, and it comes closest to Earth about every two years. This proximity is a valuable advantage and launch dates for Mars probes and satellites generally occur around the close approach. But since this encounter occurs about every two years, astronauts will need to wait for the planets to line back up again to return home.

NASA wants to send a rover to the red planet in 2020, and the agency is not alone. China, Japan, the European Space Agency and the United Arab Emirates are all gearing up to send a variety of orbiters, landers or rovers to Mars next year.

SpaceX, which billionaire Elon Musk founded with the aim of colonizing Mars, is one of several ventures vying to put people and cargo on the red planet as well. The space company is currently developing spacecraft that will first shuttle passengers to the moon and eventually to Mars.

NASA’s next Mars mission is to look for ancient life on the planet. It will carry spacesuit samples to test how well they hold up in the martian environment and an instrument that will try to convert the atmosphere, which consists mostly of carbon dioxide, into breathable oxygen.

If future missions can produce their own oxygen on Mars, that will greatly reduce the weight of the ship leaving Earth and create a more stable environment for a long-duration mission.