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To the Moon We Go Again!

September 2, 2013
Artist's rendering of LADEE, superimposed on image of the Moon (Credit: NASA).

Artist’s rendering of LADEE, superimposed on image of the Moon (Credit: NASA).

This week, we launch once more to the Moon.

On Friday, September 6, 2013, at 11:27 pm Eastern Daylight Time,  NASA’s Lunar Atmosphere and Dust Environment Explorer (LADEE, pronounced like “caddie”) — a new robotic mission — is scheduled to launch to the Moon to further explore its unusual atmosphere. LADEE’s overarching goal is to explore the precise composition of the Moon’s atmosphere, and how this changes over time. As many nations are gearing up to explore the Moon, whether for science or as a future human outpost, studying the natural composition and cycling of the lunar atmosphere is critical toward understanding how future missions could alter this natural state.

Our only natural satellite, and the fifth-largest in the solar system, our Moon is much more than a photogenic rocky body orbiting our planet once roughly every 27 days (27 days, 7 hours, 43.1 minutes, to be exact). Our Moon creates the tides, and is thought to be one of the critical factors leading to the success of life on our planet. Of great current interest is the likely existence of water ice at the poles, which would be a critical reservoir for any future permanent human presence. In addition, the Moon embodies our closest alien atmosphere; this atmosphere is so thin, in fact, that the footprints and rover tracks from the astronauts who walked on the Moon decades ago are still visible.

Watch the short video below for more information on these visible relics of human contact on the lunar surface.

The lunar atmosphere is composed of sodium, potassium, in addition to some unusual gases like argon, radon, and polonium. This atmosphere is infinitesimal compared to the Earth’s: for instance, at sea level on Earth, we breathe in an atmosphere where each cubic centimeter contains 10,000,000,000,000,000,000 molecules as compared to the fewer than 1,000,000 molecules on the Moon in the same volume. While one million molecules may seem like a lot, this would in fact be considered a rather good vacuum on Earth; it also similar in volume to the atmosphere right outside the International Space Station, orbiting ~ 370 km above our heads.

Photographed by the Expedition 28 crew aboard the International Space Station, this image shows the Moon at center with the limb of Earth near the bottom transitioning into the orange-colored troposphere, the lowest and most dense portion of the Earth's atmosphere. The troposphere ends abruptly at the tropopause, which appears in the image as the sharp boundary between the orange- and blue-colored atmosphere. The silvery-blue clouds extend far above the Earth's troposphere (Credit: NASA).

Photographed by the Expedition 28 crew aboard the International Space Station, this image shows the Moon at center with the limb of Earth near the bottom transitioning into the orange-colored troposphere, the lowest and most dense portion of the Earth’s atmosphere. The troposphere ends abruptly at the tropopause, which appears in the image as the sharp boundary between the orange- and blue-colored atmosphere. The silvery-blue clouds extend far above the Earth’s troposphere (Credit: NASA).

So, why is LADEE so important? In order to better understand our own atmosphere, on which we rely for our very survival, it is critical to understand atmospheres under a wide range of conditions. For example, we learned much about the “runaway” Greenhouse Effect on Earth from studying the searing, inhospitable atmosphere of Venus (more on that can be found here).  Right in our celestial “backyard,” the Moon’s atmosphere may in fact be the most common type of atmosphere in our solar system, and studying our nearest lunar neighbor will undoubtedly reveal important aspects of many solar system bodies that are harder to reach. Science on-board LADEE will also help pave the way for future human outposts on the Moon (more on that, below).

A wide-angle view of the Minotaur V launch vehicle at NASA's Wallops Flight Facility in Virginia, during a pathfinder exercise for NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE) Mission (Credit: NASA Wallops/Jackie Adkins).

A wide-angle view of the Minotaur V launch vehicle at NASA’s Wallops Flight Facility in Virginia, during a pathfinder exercise for NASA’s Lunar Atmosphere and Dust Environment Explorer (LADEE) Mission (Credit: NASA Wallops/Jackie Adkins).

LADEE launch, LADEE science: LADEE will be the first deep space mission to launch from NASA Goddard’s Wallops Flight Facility in Wallops, and the first aboard a Minotaur V rocket (shown above), built by the Orbital Sciences Corporation especially for small space missions. Once launched, LADEE will enter a series of Earth orbits, allowing the spacecraft to arrive at the Moon after an estimated 30-day flight duration from Earth. Once in orbit around the Moon (orbiting about once every 113 minutes), LADEE’s science mission objectives will include determining the global density, composition, and time variability of the fragile lunar atmosphere before it is perturbed by further human activity; determining the size, charge, and spatial distribution of dust grains and assessing their likely effects on lunar exploration and lunar-based astronomy; and determining  if the Apollo astronaut sightings of diffuse “glow” above the lunar surface was due to sodium or dust. These objectives will be carried out over an expected nine-month period.

An example of one of the science instruments on LADEE is shown below:

Ultraviolet and visible light spectrometer aboard LADEE. This instrument will determine the composition of the lunar atmosphere by analyzing light signatures of various molecules (Credit: NASA).

Ultraviolet and visible light spectrometer aboard LADEE. This instrument will determine the composition of the lunar atmosphere by analyzing light signatures of various molecules (Credit: NASA).

The lunar mission family: LADEE joins a large and successful family of lunar missions, shown in the illustration of the complete timeline, below. Lunar exploration began in 1959 with Luna 1 , and to date nearly 80 missions have been sent to the Moon; these include the manned Apollo missions (1969–1972) which enabled the remarkable human Moonwalks, and the return of valuable lunar samples that are still being studied by lunar and planetary scientists.

Lunar Exploration Timeline (Credit: Lunar and Planetary Institute, http://www.lpi.usra.edu/lunar/missions/).

Lunar Exploration Timeline (Credit: Lunar and Planetary Institute).

You can also see one such sample outside the Astronomy and Space Observation Lab in the Nature Research Center at the North Carolina Museum of Natural Sciences:

Moon Rock at the North Carolina Museum of Natural Sciences (Photo: R. Smith).

Moon Rock display at the North Carolina Museum of Natural Sciences. The small lunar sample is encased in the hemispherical glass casing at the top of the image (Photo: R. Smith).

The Moon, past, present, future: The Moon has been the subject of folklore, mythology, dreams, science, exploration, and imagination. We may gaze dreamily at the Moon on dark, starry nights, possibly thinking of the handful of lucky humans who explored its surface, wondering, perhaps, when we may once more send representatives of our kind. Our Moon, in fact, brought our nation together in the race to be the first to set foot on its alien surface. Further, its landscape, pocked with impact craters, is a true relic of our origins roughly 4.6 billion years ago.

As the late astronomer Carl Sagan once said, “All civilizations become either spacefaring or extinct.” We can think of the Moon as a promise toward that direction, the likely next step toward moving our species beyond our planet, and LADEE is a necessary player toward guiding us closer to engineering future human outposts and other robotic missions.

Artist's rendering of a possible future human outpost on the Moon (Credit: NASA).

Artist’s rendering of a possible future human outpost on the Moon (Credit: NASA).

For now, dream big with regard to the Moon, and enjoy being a virtual explorer from Earth as we continue to learn as much as possible about our Moon, so that one day humankind can permanently reach for the stars.

Join us!  The North Carolina Museum of Natural Sciences will be hosting a special event, “LADEE: Fly Me To The Moon“, on September 6, starting at 6 pm. Presentations  on the LADEE mission, including details on the science on-board, will take place in our Daily Planet Theater. For more information, please visit our event page, linked above.

View the launch! Information on where you can view launch broadcasts and presentation events throughout the country can be found at the link.

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