NASA Prepares for International Space Biology Mission

NASA Prepares for International Space Biology Mission

THE LUNAR ATMOSPHERE

The Lunar Atmospheric Composition Experiment . CREDIT: NASA

FROM: NASA
Article author: Brian Day
Until recently, most everyone accepted the conventional wisdom that the moon has virtually no atmosphere. Just as the discovery of water on the moon transformed our textbook knowledge of Earth’s nearest celestial neighbor, recent studies confirm that our moon does indeed have an atmosphere consisting of some unusual gases, including sodium and potassium, which are not found in the atmospheres of Earth, Mars or Venus. It’s an infinitesimal amount of air when compared to Earth’s atmosphere. At sea level on Earth, we breathe in an atmosphere where each cubic centimeter contains 10,000,000,000,000,000,000 molecules; by comparison the lunar atmosphere has less than 1,000,000 molecules in the same volume. That still sounds like a lot, but it is what we consider to be a very good vacuum on Earth. In fact, the density of the atmosphere at the moon’s surface is comparable to the density of the outermost fringes of Earth’s atmosphere where the International Space Station orbits.

What is the moon’s atmosphere made of? We have some clues. The Apollo 17 mission deployed an instrument called the Lunar Atmospheric Composition Experiment (LACE) on the moon’s surface. It detected small amounts of a number of atoms and molecules including helium, argon, and possibly neon, ammonia, methane and carbon dioxide. From here on Earth, researchers using special telescopes that block light from the moon’s surface have been able to make images of the glow from sodium and potassium atoms in the moon’s atmosphere as they are energized by the sun. Still, we only have a partial list of what makes up the lunar atmosphere. Many other species are expected.

We think that there are several sources for gases in the moon’s atmosphere. These include high energy photons and solar wind particles knocking atoms from the lunar surface, chemical reactions between the solar wind and lunar surface material, evaporation of surface material, material released from the impacts of comets and meteoroids, and out-gassing from the moon’s interior. But which of these sources and processes are important on the moon? We still don’t know.

With the discovery of significant ice deposits at the moon’s poles by NASA's Lunar CRater Observation and Sensing Satellite (LCROSS) and Lunar Reconnaissance Orbiter (LRO) missions, and the discovery of a thin scattering of water molecules in the lunar soil by the Chandrayaan X-ray Observatory, another fascinating possibility has captured researchers’ interest. The moon’s atmosphere may play a key role in a potential lunar water cycle, facilitating the transport of water molecules between polar and lower latitude areas. The moon may not only be wetter than we once thought, but also more dynamic.

One of the critical differences between the atmospheres of Earth and the moon is how atmospheric molecules move. Here in the dense atmosphere at the surface of Earth, the molecules’ motion is dominated by collisions between the molecules. However the moon’s atmosphere is so thin, atoms and molecules almost never collide. Instead, they are free to follow arcing paths determined by the energy they received from the processes described above and by the gravitational pull of the moon.


The technical name for this type of thin, collision-free atmosphere that extends all the way down to the ground is a "surface boundary exosphere." Scientists believe this may be the most common type of atmosphere in the solar system. In addition to the moon, Mercury, the larger asteroids, a number of the moons of the giant planets and even some of the distant Kuiper belt objects out beyond the orbit of Neptune, all may have surface boundary exospheres. But in spite of how common this type of atmosphere is, we know very little about it. Having one right next door on our moon provides us with an outstanding opportunity to improve our understanding.

Among the goals of the Lunar Atmosphere and Dust Environment Explorer (LADEE) are to determine the composition and structure of the tenuous lunar atmosphere and to understand how these change with time, and as external conditions vary. LADEE’s measurements come at a key time: with increasing interest in the moon by a number of nations, future missions could significantly affect the natural composition of the lunar atmosphere.

THE LAUNCH OF THE ANTARES ROCKET

FROM: NASA

Antares Rocket Launches
The Orbital Sciences Corporation Antares rocket is seen as it launches from Pad-0A of the Mid-Atlantic Regional Spaceport (MARS) at the NASA Wallops Flight Facility in Virginia, Sunday, April 21, 2013.

The test launch marked the first flight of Antares and the first rocket launch from Pad-0A. The Antares rocket delivered the equivalent mass of a spacecraft, a so-called mass simulated payload, into Earth's orbit.

Image Credit: NASA/Bill Ingalls

El segundo lanzamiento de Vega se retrasa 24 horas

El segundo lanzamiento de Vega se retrasa 24 horas

U.S. Department of Defense Armed with Science Update: STAR WARS and Defense Education

U.S. Department of Defense Armed with Science Update

Herschel demuestra que el agua hallada en Júpiter procede del impacto de un cometa

Herschel demuestra que el agua hallada en Júpiter procede del impacto de un cometa

Descubre este libro!

Descubre este libro!

Cara a cara con Encélado

Cara a cara con Encélado

Week In Images

Week In Images

NASA VIEW OF THE HORSEHEAD NEBULA

FROM: NASA

Hubble Sees a Horsehead of a Different Color
Astronomers have used NASA's Hubble Space Telescope to photograph the iconic Horsehead Nebula in a new, infrared light to mark the 23rd anniversary of the famous observatory's launch aboard the space shuttle Discovery on April 24, 1990.

Looking like an apparition rising from whitecaps of interstellar foam, the iconic Horsehead Nebula has graced astronomy books ever since its discovery more than a century ago. The nebula is a favorite target for amateur and professional astronomers. It is shadowy in optical light. It appears transparent and ethereal when seen at infrared wavelengths. The rich tapestry of the Horsehead Nebula pops out against the backdrop of Milky Way stars and distant galaxies that easily are visible in infrared light.

Hubble has been producing ground-breaking science for two decades. During that time, it has benefited from a slew of upgrades from space shuttle missions, including the 2009 addition of a new imaging workhorse, the high-resolution Wide Field Camera 3 that took the new portrait of the Horsehead. Image Credit-NASA-ESA-Hubble Heritage Team.

 

THE FIRST SHUTTLE LAUNCH

FROM: NASA

A new era in space flight began on April 12, 1981, when Space Shuttle Columbia, or STS-1, soared into orbit from NASA's Kennedy Space Center in Florida. Astronaut John Young, a veteran of four previous spaceflights including a walk on the moon in 1972, commanded the mission. Navy test pilot Bob Crippen piloted the mission and would go on to command three future shuttle missions. The shuttle was humankind's first re-usable spacecraft. The orbiter would launch like a rocket and land like a plane. The two solid rocket boosters that helped push them into space would also be re-used, after being recovered in the ocean. Only the massive external fuel tank would burn up as it fell back to Earth. It was all known as the Space Transportation System. Twenty years prior to the historic launch, on April 12, 1961, the era of human spaceflight began when Russian Cosmonaut Yuri Gagarin became the first human to orbit the Earth in his Vostock I spacecraft. The flight lasted 108 minutes. Pictured here: a timed exposure of STS-1, at Launch Pad A, Complex 39, turns the space vehicle and support facilities into a night- time fantasy of light. Structures to the left of the shuttle are the fixed and the rotating service structure. Image Credit: NASA

U.S. Department of Defense Armed with Science Update

U.S. Department of Defense Armed with Science Update

Nepřetrhnutelné kosmické lanko

Nepřetrhnutelné kosmické lanko

U.S. Department of Defense Armed with Science Update: Space Station Solar Arrays

U.S. Department of Defense Armed with Science Update

X-48 PROJECT COMPLETES RESEARCH

FROM:  NASA
X-48 Project Completes Flight Research for Cleaner, Quieter Aircraft

EDWARDS, Calif. -- NASA's remotely piloted X-48C hybrid-wing-body subscale aircraft, which demonstrates technology concepts for cleaner and quieter commercial air travel, completed an eight-month flight research campaign on April 9.

The C model of the X-48 aircraft flew its first flight at Edwards Aug. 7 and its 30th flight brought the productive research project to a close.

"We have accomplished our goals of establishing a ground-to-flight database, and proving the low speed controllability of the concept throughout the flight envelope," said Fay Collier, manager of NASA's Environmentally Responsible Aviation project. "Very quiet and efficient, the hybrid wing body has shown promise for meeting all of NASA's environmental goals for future aircraft designs."

The scale-model aircraft, shaped like a manta ray, was designed by The Boeing Co., built by Cranfield Aerospace Limited of the United Kingdom, and flown in partnership with NASA. The X-48C is a version of NASA's X-48B blended wing body aircraft modified to evaluate the low-speed stability and control of a low-noise version of a notional hybrid-wing-body design. This design features a flattened fuselage with no tail, and engines mounted on top of the fuselage at the rear of the plane. The design stems from concept studies for commercial aircraft that could be flying within 20 years. The studies are under way in NASA's Environmentally Responsible Aviation Project.

"Our team has done what we do best: flight-test a unique aircraft and repeatedly collect data that will be used to design future 'green' airliners," said Heather Maliska, X-48C project manager at NASA's Dryden Flight Research Center in California. "It is bittersweet to see the program come to an end, but we are proud of the safe and extremely successful joint Boeing and NASA flight test program that we have conducted."

The X-48C retained most dimensions of the B model, with a wingspan slightly longer than 20 feet and a weight of about 500 pounds. Primary changes to the X-48C model from the B model, which flew 92 flights at Dryden between 2007 and 2010, were geared to transforming it to an airframe noise-shielding configuration. External modifications included relocating the wingtip winglets inboard next to the engines, effectively turning them into twin tails. The rear deck of the aircraft was extended about two feet. Finally, the project team replaced the X-48B's three 50-pound thrust jet engines with two 89-pound thrust engines. The aircraft had an estimated top speed of about 140 mph and a maximum altitude of 10,000 feet.

"Working closely with NASA, we have been privileged throughout X-48 flight-testing to explore and validate what we believe is a significant breakthrough in the science of flight and this has been a tremendous success for Boeing," said Bob Liebeck, a Boeing senior technical fellow and the company's Blended Wing Body (BWB) Program manager. "We have shown a BWB aircraft, which offers the tremendous promise of significantly greater fuel efficiency and reduced noise, can be controlled as effectively as a conventional tube-and-wing aircraft during takeoffs, landings and other low-speed segments of the flight regime."

"Our goal was to define the low-speed envelope and explore the low-speed handling qualities of the blended wing body class of tailless aircraft, and we have accomplished that," added Mike Kisska, Boeing X-48 project manager.

Because handling qualities of the X-48C were different from those of the X-48B, the project team modified the flight control system software, including flight control limiters to keep the airplane flying within a safe flight envelope. This enabled a stronger and safer prototype flight control system suitable for future full-scale commercial hybrid or blended wing aircraft.

NASA's Aeronautics Research Mission Directorate and Boeing funded the X-48 technology demonstration research effort, which supported NASA's goals of reduced fuel burn, emissions, and noise. The Air Force Research Laboratory in Dayton, Ohio, also was a member of the project team.