(CNN) - NASA is set to launch the world's largest rocket Tuesday, conducting research to help return astronauts to the moon.

The 327-foot rocket, called the Ares I-X, is set to launch at 8 a.m. ET from Kennedy Space Center in Florida, NASA said. The empty rocket will help NASA collect information for future missions.

NASA's new Ares test vehicle is ready on its launch platform at Kennedy Space Center in Florida. (Getty Images)

"Ares I-X will bring NASA one step closer to its exploration goals to return to the moon for ambitious exploration," NASA said in statement.

The launch, which NASA is calling a test, is among four test launches of Ares I-X that will go on until 2012.

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(CNN) - Two U.S. spacecraft are set to crash on the moon Friday. On purpose. And we're all invited to watch.

[cnn-photo-caption image= http://i2.cdn.turner.com/cnn/2009/TECH/space/10/08/probe.moon.crash/art.lcross.nasa.jpg caption="An artist's rendering shows the LCROSS spacecraft, left, separating from its Centaur rocket."]

NASA's Lunar Crater Observation and Sensing Satellite is scheduled to drop its Centaur upper-stage rocket on the lunar surface at 7:31 a.m. ET.

NASA hopes the impact will kick up enough dust to help the LCROSS probe find the presence of water in the moon's soil. Four minutes later, the LCROSS will follow through the debris plume, collecting and relaying data back to Earth before crashing into the Cabeus crater near the moon's south pole.

The LCROSS is carrying spectrometers, near-infrared cameras, a visible camera and a visible radiometer. These instruments will help NASA scientists analyze the plume of dust - more than 250 metric tons' worth - for water vapor.

The orbiting Hubble Space Telescope and NASA's Lunar Reconnaissance Orbiter will watch, and photograph, the collisions. And hundreds of telescopes on Earth also will be focused on the two plumes.

NASA is encouraging amateur astronomers to join the watch party.

"We expect the debris plumes to be visible through midsized backyard telescopes - 10 inches and larger," said Brian Day at NASA's Ames Research Center at Moffett Field, California. Day is an amateur astronomer who is leading education and public outreach for the LCROSS mission.

Ames will host "Impact Night," an event with music and food starting Thursday evening before a live transmission of the lunar impact will be shown around 4:30 a.m. PT Friday. Other science observatories and amateur astronomy clubs across the country will be hosting similar events. iReport: Are you planning to watch?

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Editor's note: Buzz Aldrin, whose new book is "Magnificent Desolation," was one of the two American astronauts who were the first people to set foot on the moon.

[cnn-photo-caption image= http://i2.cdn.turner.com/cnn/2009/images/06/23/art.buzz.aldrin.moon.jpg caption="Buzz Aldrin walks on the moon in a photo taken by Neil Armstrong, his colleague on the 1969 mission. "]

By Buzz Aldrin
Special to CNN

(CNN) - Four decades have passed since the summer of 1969, when Neil Armstrong, Mike Collins and I flew America's first lunar landing mission.

The passage of time has not faded either the memory of that summer or the importance of what we achieved, for our mission was about more than just exploring the moon.

On July 20, 1969, Neil and I were peering out the window of our lunar lander, the Eagle, as it descended toward the lunar surface. The ship's computer was steering us toward a field of boulders the size of cars.

That same computer - with less power than today's pocket calculators - was signaling that it was overworked and dangerously overloaded. Our single tank of fuel was nearly empty as we approached the surface, invisible to us, cloaked in a cloud of swirling dust.

Neil took manual control and flew us toward a smoother terrain. Then, as the shadow of our landing gear appeared etched onto the surface in the gloom, a light on our console flashed that contact had been made.

"Houston, Tranquility Base Here," Neil radioed to the listening world back home. "The Eagle has landed!"

For more than two hours, we explored the moon's dusty surface. We could easily tell that the planet we had landed on was very different from our home. The horizon visibly curved away in the distance, a sign of the moon's much smaller landscape.

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Retired Shuttle commander and Marine Corps General Charlie Bolden is expected to meet today with President Obama. It is believed Bolden is Obama's choice to head NASA at a time the space agency is at crossroads.