Apollo11 - Blog Posts

Throwback Thursday: Answers to Apollo Moon Landing Questions

The first six missions to the Moon helped us answer questions about our nearest celestial neighbor, but a curious public wanted to know more about how we did it. With the help of the NASA History Office, we’ve identified some of the most frequently asked questions surrounding the first time humans walked on the surface of another world. Read on and click here to check out our post from last week and the week before. 

Why do some shadows on the Moon appear to go in different directions?

For Apollo astronauts, the Sun wasn’t the sole source of light. The high reflectivity of the lunar surface or “albedo” means that the Moon's many craters, hills and rocks bounce sunlight to wash out the stars multiple shadows on objects. The highly uneven terrain means that shadows can have slightly different lengths, as well. For example, two astronauts standing several feet away from each other can have different shadow lengths because one may be on a slope.

While the Lunar Module itself was also reflective, Apollo astronauts had yet another bright source of light: Earth! To a moonwalker, a half-full Earth would be about 20 times brighter than a full Moon as seen from our home planet. This also explains why stars are not visible in pictures. Think about it: if you wanted to photograph all the stars that can be seen from Earth, would you want to do it during a full Moon? 

Why are there no blast craters under the Lunar Modules? 

The Moon has endured billions of years of bombardment from micrometeorites and large meteorites, compacting the dust into extremely dense rock. A thin layer of fine and powdery moondust covers the ground, but the dense rock beneath this layer makes it hard to penetrate the surface. That, paired with an engine thrusting in a vacuum means that the exhaust would expand rapidly outward instead of straight down like it would on Earth. The large engine nozzle. Still, many pictures clearly show dust markings radiating from the landing site. 

Can Humans Really Survive Passing Through the Van Allen Radiation Belts?

The short answer is yes, but with protection. The Van Allen radiation belts, named after their discoverer James van Allen, are regions high above Earth’s surface that trap highly charged particles that radiate off the Sun. This energetic region contains harmful radiation that would be lethal to anybody who encountered them unprotected. Thankfully, the 12 astronauts that passed through the belts did so relatively quickly in the comfort of their shielded spacecraft that had been tested to withstand high doses of radiation. Although all six crews had to pass through the Van Allen belts, the dosimeters indicated that they received a dosage no higher than that of a chest X-ray or a single CAT scan. 

Why are we going back to the Moon?

Exploring the Moon is only the first part in our mission to expand humanity’s presence on Mars and beyond. The Moon is the ideal stepping stone for testing technology that will enable us to expand humanity’s presence on Mars and beyond. Click here to learn more about the Artemis program that will take humans to the lunar surface within five years -- this time, to stay. Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

They Put a Flag on the Moon

It’s 1969 and Apollo 11 astronauts Buzz Aldrin and Neil Armstrong are the first humans to land on the Moon. In now iconic footage, Aldrin and Armstrong carefully assemble and maneuver an American flag to place on the lunar surface. The fabric unfurls, staying suspended without any wind to animate the stars and stripes. The flagpole sways precariously as the crew work to anchor it in the Moon’s low gravity at just 1/6th that of Earth’s. How did this moment come about? On Flag Day, let’s dive behind-the-scenes of what led to getting the American flag on the Moon 50 years ago.

Image: Astronaut Buzz Aldrin poses for a photograph beside the deployed United States flag during the Apollo 11 mission.

Seeking to empower the nation, President John F. Kennedy gave us a grand charge. The human spaceflight program of the early 1960s was challenged to work on missions that sent humans to the surface of another world. Following President Kennedy’s death in 1963, President Richard Nixon stressed a more international perspective to the Apollo missions. To reconcile the need for global diplomacy with national interests, we appointed the Committee on Symbolic Activities for the First Lunar Landing.

Image: NASA Administrator Thomas Paine and President Richard Nixon are seen aboard the USS Hornet, Apollo 11’s splashdown recovery vessel.

The committee, and the U.S. at large, wanted to avoid violating the United Nations Outer Space Treaty, which prohibited any nation from taking possession of a celestial body. After some debate, they recommended that the flag only appear during the Apollo 11 spacewalk. A plaque would accompany it, explaining that the flag was meant to stand for peaceful exploration, not conquest. 

Image: The plaque reads “Here men from the planet Earth first set foot upon the Moon July 1969 A.D. We came in peace for all of mankind.” Under the text are signatures by President Nixon, Buzz Aldrin, Neil Armstrong, and Michael Collins.

A team of engineers at Johnson Space Center had three months to resolve several issues regarding the flag’s assembly. First, was the Moon’s lack of atmosphere. The flag, quite literally, could not fly the way it does on Earth. To address this, a horizontal crossbar was added to support the flag’s weight and give the illusion of it waving.

Image: NASA technician David L. McCraw shows the flag next to a Lunar Module mockup.

Second was the flag’s assembly, which had to be as lightweight and compact as possible so as not to take up limited storage space. The completed package, which was attached to Lunar Module’s ladder, weighed just under ten pounds. It received an outer case made of steel, aluminum, and Thermoflex insulation and blanketing to shield the flag from the 2,000 degree Fahrenheit spike from the Eagle’s descent engine.

Image: Component pieces of the flag assembly.

The last issue was mobility. Bulky spacesuits significantly restricted the astronauts’ range of motion, and suit pressurization limited how much force they could apply. To accommodate these limits, the team included telescoping components to minimize the need to reach and maneuver the poles. A red painted ring on the flagpole indicated how far into the ground it should be driven. Hinges and catches would lock into place once the pieces were fully extended.

Image: Diagram from the 1969 Apollo 11 press release illustrating astronaut spacesuit reach capabilities and ideal working height.

Fifty years after Apollo 11, the flag we planted on the lunar surface has likely faded but its presence looms large in United States history as a symbol of American progress and innovation.

Image: A close-up view of the U.S. flag deployed on the Moon at the Taurus-by the crew of Apollo 17, the most recent lunar landing mission.

The story doesn’t stop here. Anne Platoff's article “Where No Flag Has Gone Before” sheds more light on the context and technical process of putting the United States flag on the Moon. You can also check out Johnson Space Center’s recent feature story that details its presence in later missions. Happy Flag Day!  Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

Sixty Years of Exploration, Innovation, and Discovery!

Exactly sixty years ago today, we opened our doors for the first time. And since then, we have opened up a universe of discovery and innovation. 

There are so many achievements to celebrate from the past six decades, there’s no way we can go through all of them. If you want to dive deeper into our history of exploration, check out NASA: 60 Years and Counting. 

In the meantime, take a moonwalk down memory lane with us while we remember a few of our most important accomplishments from the past sixty years!

In 1958, President Eisenhower signed the National Aeronautics and Space Act, which effectively created our agency. We officially opened for business on October 1. 

To learn more about the start of our space program, watch our video: How It All Began. 

Alongside the U.S. Air Force, we implemented the X-15 hypersonic aircraft during the 1950s and 1960s to improve aircraft and spacecraft. 

The X-15 is capable of speeds exceeding Mach 6 (4,500 mph) at altitudes of 67 miles, reaching the very edge of space. 

Dubbed the “finest and most productive research aircraft ever seen,” the X-15 was officially retired on October 24, 1968. The information collected by the X-15 contributed to the development of the Mercury, Gemini, Apollo, and Space Shuttle programs. 

To learn more about how we have revolutionized aeronautics, watch our Leading Edge of Flight video. 

On July 20, 1969, Neil Armstrong and Buzz Aldrin became the first humans to walk on the moon. The crew of Apollo 11 had the distinction of completing the first return of soil and rock samples from beyond Earth. 

Astronaut Gene Cernan, during Apollo 17, was the last person to have walked on the surface of the moon. (For now!)

The Lunar Roving Vehicle was a battery-powered rover that the astronauts used during the last three Apollo missions. 

To learn more about other types of technology that we have either invented or improved, watch our video: Trailblazing Technology.

Our long-term Earth-observing satellite program began on July 23, 1972 with the launch of Landsat 1, the first in a long series (Landsat 9 is expected to launch in 2020!) We work directly with the U.S. Geological Survey to use Landsat to monitor and manage resources such as food, water, and forests. 

Landsat data is one of many tools that help us observe in immense detail how our planet is changing. From algae blooms to melting glaciers to hurricane flooding, Landsat is there to help us understand our own planet better. 

Off the Earth, for the Earth.

To learn more about how we contribute to the Earth sciences, watch our video: Home, Sweet Home. 

Space Transportation System-1, or STS-1, was the first orbital spaceflight of our Space Shuttle program. 

The first orbiter, Columbia, launched on April 12, 1981. Over the next thirty years, Challenger, Discovery, Atlantis, and Endeavour would be added to the space shuttle fleet. 

Together, they flew 135 missions and carried 355 people into space using the first reusable spacecraft.

On January 16, 1978, we selected a class of 35 new astronauts--including the first women and African-American astronauts. 

And on June 18, 1983, Sally Ride became the first American woman to enter space on board Challenger for STS-7. 

To learn more about our astronauts, then and now, watch our Humans in Space video.

Everybody loves Hubble! The Hubble Space Telescope was launched into orbit on April 24, 1990, and has been blowing our minds ever since. 

Hubble has not only captured stunning views of our distant stars and galaxies, but has also been there for once-in-a-lifetime cosmic events. For example, on January 6, 2010, Hubble captured what appeared to be a head-on collision between two asteroids--something no one has ever seen before.

In this image, Hubble captures the Carina Nebula illuminating a three-light-year tall pillar of gas and dust. 

To learn more about how we have contributed to our understanding of the solar system and beyond, watch our video: What’s Out There?

Cooperation to build the International Space Station began in 1993 between the United States, Russia, Japan, and Canada. 

The dream was fully realized on November 2, 2000, when Expedition 1 crew members boarded the station, signifying humanity’s permanent presence in space!

Although the orbiting lab was only a couple of modules then, it has grown tremendously since then! 

To learn more about what’s happening on the orbiting outpost today, visit the Space Station page.

We have satellites in the sky, humans in orbit, and rovers on Mars. Very soon, we will be returning humankind to the Moon, and using it as a platform to travel to Mars and beyond.

And most importantly, we bring the universe to you. 

What are your favorite NASA moments? We were only able to share a few of ours here, but if you want to learn about more important NASA milestones, check out 60 Moments in NASA History or our video, 60 Years in 60 Seconds. 

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

Happy #MoonDay! To celebrate the 49th anniversary of Apollo 11 landing on the Moon, we present you with “Moonlight,” a video by our Goddard science visualizer Ernie Wright set to Debussy’s Clair de Lune. The Apollo missions were a landmark in lunar exploration. The visit and the samples that our Moon walkers collected transformed our understanding of the Moon and the solar system. Now, our Lunar Reconnaissance Orbiter’s high-resolution data gives an incredibly detailed view of our closest neighbor.

This visualization captures the mood of Claude Debussy's best-known composition, Clair de Lune (which means moonlight in French). The piece was published in 1905 as the third of four movements in the composer's Suite Bergamasque, and unlike the other parts of this work, Clair is quiet, contemplative, and slightly melancholy, evoking the feeling of a solitary walk through a moonlit garden.

“Moonlight” uses a digital 3D model of the Moon built from Lunar Reconnaissance Orbiter global elevation maps and image mosaics. The lighting is derived from actual Sun angles during lunar days in 2018. Enjoy and read more HERE.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.