When the first humans stepped onto the moon a half-century ago on July 20, 1969, they knew they were venturing into the unknown. Some had feared their lander would be swallowed up by bottomless layers of dust as almost nothing was known about the moon surface at the time. But they knew it wouldn't, thanks in large part to groundbreaking research being performed at the University of Arizona's then fledging Lunar and Planetary Laboratory, or LPL.

When Gerard P. Kuiper founded the laboratory nine years earlier, in 1960, there was skepticism and a lack of interest in humans visiting the moon. But reaching the moon became a priority as the space race ramped up in the early '60s. Kuiper and his UA laboratory was suddenly in demand.

Now, on the 50th anniversary of the first manned mission to the moon marked by the Apollo 11 landing, UA scientists celebrate the pioneering and pivotal role the UA has held in the explosion of space science research, helping to shape what we know about our solar system and beyond today.

"The UA has been a part of nearly every NASA planetary exploration mission, and with leadership roles on many of them," said Tim Swindle, director of the UA Department of Planetary Sciences and LPL. "Our graduates and alumni have also been involved in many missions. That is our goal."

William K. Hartmann, a UA alumnus who studied with Kuiper, was instrumental in helping to create some of the first maps of the moon.

"We projected photos of the moon onto a white globe, then photographed the globe from different angles to make an atlas of lunar features from overhead, as they would be seen by astronauts orbiting the moon," Harmann said.

He also shaped early theories around the origins of Earth's moon and has made other significant contributions to the field of lunar science.

Over the course of his scientific career, Hartmann discovered several impact basins on the moon. During the 1960s, he predicted the age of the lunar lava plains. His predictions were confirmed through samples returned by the Apollo missions.

The Apollo missions also influenced Kuiper while at the UA. He took his students on field trips to places on Earth that he felt were representative of what students might see on the moon or in the solar system, such as Meteor Crater in northern Arizona, dune fields or the extensive lava flows blanketing the Big Island of Hawaii. Those types of instructive field trips continue today.

"During our field trips, students visit planetary analog sites," Swindle said. "It's an important part of our department culture. We can send a robotic spacecraft to places in our solar system and beyond, but we'll never be able to see them as well as we can see places on Earth. By comparing those sites using every scientific technique we can think of, we can learn what those places out there in space might be like."

In preparation for the Phoenix Mars mission, the first planetary mission led by a university, a UA team traveled to Antarctica to study how the instruments they had developed would work in what is considered the most Mars-like environment on Earth.

The LPL's legacy of studying places on Earth to understand places far, far away becomes more relevant as more powerful telescopes have begun discovering a growing list of planets orbiting other stars as well as stranger objects within our solar system, such as the asteroid Bennu.

Instruments onbord OSIRIS-REx, a UA-led sample-return mission, are currently imaging and mapping Bennu's surface. Planetary scientist and UA professor Erik Asphaug took courses at the UA in both astronomy and geoscience and is currently analyzing OSIRIS-REx images to understand the phsyics of Bennu's rocky surface in microgravity and its composition.

In September 2023, OSIRIS-REx will return with prestine samples scooped from Bennu. The samples will be studied to learn more about the earliest history of the solar system, much like the lunar rocks returned from the Apollo missions.

"Kuiper started with the right attitude and what was an unusual approach at the time – namely turning astronomical objects into places," Swindle said. "His guiding idea was to not just obtain higher and higher resolution images, but also figure out what those images mean and what those objects would look like if you were standing there. And that is really what we have been doing here at LPL ever since."

A Brief History of UA Involvement in Space Exploration Missions

1961-1965: The Ranger probes were the first effort by the U.S. to launch a spacecraft from the Earth to reach the moon. After several failed attempts, Ranger 7 finally reached the moon and sent the first close-up photos of the lunar surface as it approached. The Ranger missions laid the groundwork for the Surveyor missions. UA astronomer Kuiper was the lead scientist for the program.

1966-1968: A series of seven robotic spacecraft named Surveyor were the first to land intact on the lunar surface and send photographs. The Surveyor missions laid the groundwork for the Apollo missions. LPL's Ewen Whitaker was instrumental in comparing the Surveyor images of the lunar surface with telescopic images to determine their precise locations.

1968-1969: The Apollo missions led up to the most famous mission of all, Apollo 11, when humans landed on the moon for the first time in 1969. Robert Strom, of the LPL, was involved with the Apollo 8, 10 and 11 missions as part of the lunar operations working groups.

1972-1973: NASA's Pioneer 10 and 11 spacecraft were launched as scouts for the  Voyager spacecraft that would follow. Both probes were equipped with UA imaging equipment built by LPL's Tom Gehrels.

1975: NASA's Viking spacecraft collected high-resolution images of the surface of Mars and carried out surface experiments to locate signs of life. LPL's Brad Smith was in charge of the imaging team.

1977: NASA's Voyager probes 1 and 2 were initially launched to take advantage of an ideal alignment of the planets, creating a "Grand Tour" of the solar system. Both Voyagers are now on course to exit the solar system, studying the Kuiper Belt (named after UA astronomer Gerard Kuiper), heliosphere and interstellar space.

1978: NASA's Pioneer-Venus mission was launched in two separate parts: an orbiter and a multiprobe that was inserted into Venus’ atmosphere.

1989: Launch of NASA's Galileo, a spacecraft to study Jupiter and its moons.

1990: Launch of NASA's Ulysses spacecraft, designed to examine and study the Sun at close range.

1996: Launch of NASA's Near-Earth Asteroid Rendezvous, or NEAR, spacecraft to study an asteroid close to Earth.

1996: Mars Pathfinder was a two-part craft that, after the Viking probes, was the third NASA mission to successfully land on Mars. LPL's Peter Smith built the Imager instrument for the Mars Pathfinder.

1997: Launch of NASA's Cassini-Huygens spacecraft to study Saturn and its multiple moons. The Huygens lander successfully impacted on Saturn's moon Titan, recording its entire entry and landing via its Descent Imager/Spectral Radiometer, designed and operated by LPL's Marty Tomasko. LPL's Robert Brown led the science team for the Cassini Visual and Infrared Mapping Spectrometer.

2001: NASA's Mars Odyssey mission, currently the longest-operating robotic spacecraft orbiting Mars, discovered large quantities of frozen water on the red planet, using an instrument designed and built by LPL's Bill Boynton.

2004: NASA's Mercury Surface, Space Environment, Geochemistry, and Ranging – or MESSENGR – spacecraft is the first to orbit Mercury and study the planet's chemical composition, geology and magnetic field.

2005: NASA's Deep Impact mission, designed to study comet 9P/Tempel, revealed that the comet contains more dust than ice.

2005: NASA's High Resolution Imaging Science Experiment, or HiRISE, is the largest camera to ever go into deep space to collect images of the Martian surface. HiRISE is operated by the UA under the leadership of LPL's Alfred McEwen.

2007: NASA's Phoenix Mars Lander mission, led by the UA under the direction of LPL's Peter Smith, was the first mission to Mars ever led by a university. It was also the first spacecraft to visit one of Mars' enigmatic polar regions.

2016: Launch of the UA-led Origins Spectral Interpretation Resource Identification Security Regolith Explorer – or OSIRIS-REx – mission, under the direction of LPS's Dante Lauretta, to the near-Earth asteroid Bennu. OSIRIS-REx will be the first NASA mission to acquire a pristine sample from an asteroid, which it will return to Earth by 2023 for further study.

2017: NASA funds the UA-led GUSTO mission. The goal of the $40 million endeavor is to send a balloon to near-space, carrying a telescope that will study the interstellar medium. The high-altitude, ultralong-duration balloon is scheduled for launch on Dec. 15, 2021. Christopher Walker, of the UA's Steward Observatory with joint appointments in the colleges of optical sciences and engineering, leads the mission.

2018: Launch of NASA's Parker Solar Probe, the first spacecraft to orbit close to the sun and study the solar wind at its source, rather than in Earth's orbit. LPL's Joe Giacalone and Kristopher Klein lead the mission.

2019: An inflatable space antenna designed by UA students is selected by NASA to fly as auxiliary payloads aboard space missions planned to launch in 2020, 2021 and 2022. The selections are part of the 10th round of NASA’s CubeSat Launch Initiative.