Electric Moon Jolts the Solar Wind

ARTEMIS P1 is seen in relation with the orbit of its twin P2 and the GRAIL twins Ebb and Flow below them in low lunar orbit. Together with with the Lunar Reconnaissance Orbiter NASA presently has five vehicles in lunar orbit. The schematic animation can be explored in startling depth using NASA's online Eyes on the Solar System application [NASA/Science].

With the Moon as the most prominent object in the night sky and a major source of an invisible pull that creates ocean tides, many ancient cultures thought it could also affect our health or state of mind -- the word “lunacy” has its origin in this belief. Now, a powerful combination of spacecraft and computer simulations is revealing that the Moon does indeed have a far-reaching, invisible influence -- not on us, but on the Sun, or more specifically, the solar wind.

The solar wind is a thin stream of electrically conducting gas called plasma that’s constantly blown off the surface of the Sun in all directions at around a million miles per hour. When a particularly fast, dense or turbulent solar wind strikes Earth’s magnetic field, it can generate magnetic and radiation storms that are capable of disrupting satellites, power grids, and communication systems. The magnetic “bubble” surrounding Earth also pushes back on the solar wind, creating a bow shock tens of thousands of miles across over the day side of Earth where the solar wind slams into the magnetic field and abruptly slows from supersonic to subsonic speed.

Unlike Earth, the Moon is not surrounded by a global magnetic field. “It was thought that the solar wind crashes into the lunar surface without any warning or ‘push back’ on the solar wind,” says Dr. Andrew Poppe of the University of California, Berkeley. Recently, however, an international fleet of lunar-orbiting spacecraft has detected signs of the Moon’s presence “upstream” in the solar wind. “We’ve seen electron beams and ion fountains over the Moon’s day side,” says Dr. Jasper Halekas, also of the University of California, Berkeley.

These phenomena have been seen as far as 10,000 kilometers above the Moon and generate a kind of turbulence in the solar wind ahead of the Moon, causing subtle changes in the solar wind’s direction and density. The electron beams were first seen by NASA’s Lunar Prospector (1998-1999), while the Japanese Kaguya (2007-2009) mission, the Chinese Chang’e-1 mission, and the Indian Chandrayaan-1 mission all saw ion plumes at low altitudes. 

NASA’s ARTEMIS mission has now also seen both the electron beams and the ion plumes, plus newly identified electromagnetic and electrostatic waves in the plasma ahead of the Moon, at much greater distances from the Moon. “With ARTEMIS, we can see the plasma ring and wiggle a bit, surprisingly far away from the Moon,” says Halekas. ARTEMIS stands for “Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon’s Interaction with the Sun”.

“An upstream turbulent region called the ‘foreshock’ has long been known to exist ahead of the Earth’s bow shock, but the discovery of a similar turbulent layer at the Moon is a surprise,” said Dr. William Farrell of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Farrell is lead of the NASA Lunar Science Institute’s Dynamic Response of the Environment At the Moon (DREAM) lunar science center, which contributed to the research.

Computer simulations help explain these observations by showing that a complex electric field near the lunar surface is generated by sunlight and the flow of the solar wind. The simulation reveals this electric field can generate electron beams by accelerating electrons blasted from surface material by solar ultraviolet light. Also, related simulations show that when ions in the solar wind collide with ancient, “fossil” magnetic fields in certain areas on the lunar surface, they are reflected back into space in a diffuse, fountain-shaped pattern. These ions are mostly the positively charged ions (protons) of hydrogen atoms, the most common element in the solar wind.

“It’s remarkable that electric and magnetic fields within just a few meters (yards) of the lunar surface can cause the turbulence we see thousands of kilometers away,” says Poppe. When exposed to solar winds, other moons and asteroids in the solar system should have this turbulent layer over their day sides as well, according to the team.

“Discovering more about this layer will enhance our understanding of the Moon and potentially other bodies because it allows information about conditions very near the surface to propagate to great distances, so a spacecraft will gain the ability to virtually explore close to these objects when it’s actually far away,” said Halekas.

Students to exhibit GRAIL MoonKAM images

Forward view from a MoonKAM camera on-board GRAIL Ebb looks down into 29.6 kilometer Titov and south-southwestward over surrounding floor of Mare Moscoviense, in the northern lunar farside. MoonKam image 8108, Robert McCall School, May 19, 2012 [NASA/Caltech-JPL/MIT/SRS].

Reporters have been invited to an exhibit of student-directed MoonKam images of the lunar surface captured by NASA's GRAIL twin spacecraft, Ebb and Flow, Friday, June 1, from 10 am until Noon, EDT, at the Ronald Reagan Building and International Trade Center, 1300 Pennsylvania Avenue NW, Washington, DC.

The event will showcase the MoonKAM (Moon Knowledge Acquired by Middle school students) education and public outreach project flying in lunar orbit on the GRAIL spacecraft. 

MoonKAM provides students around the world with an opportunity to identify and choose images of the moon's surface using small cameras aboard NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission. Thousands of images of lunar targets have been selected by fifth to eighth-grade students since.the GRAIL twins arrived in lunar orbit with the New Year.

MoonKAM is operated by Sally Ride Science in collaboration with undergraduate students at the University of California in San Diego. 

Sally Ride, CEO of the science education company (and America's first woman in space) will host the event and provide opening remarks. Event presenters include NASA deputy administrator Lori Garver and GRAIL principal investigator Maria Zuber of the Massachusetts Institute of Technology, Cambridge, Massachusetts.

Meanwhile, it was announced earlier this week that the primary science mission of the GRAIL mission was completed ahead of schedule. An extended mission will continue at least through December.

"To mine the stars, hire a mining engineer"

Astrobotic Technology, a competitor for the Google Lunar X-Prize, is engaged in a two-year contract with NASA to develop a prototype robotic excavator to recover water and methane near the Moon’s north pole. Hydrogen compounds and other volatiles mined from the Moon can be transformed for life support and fuel would otherwise continue to be very expensive to transport beyond Earth's atmosphere [Astrobotic Technologies, Inc.].

George Leopold
EET

There’s been a lot of talking lately about mining asteroids for precious metals like platinum. A group of space entrepreneurs recently announced the formation of a company called Planetary Resources to pursue that ambitious goal.

We asked a former miner and NASA engineer who now writes about subjects like mining the moon whether something as audacious as asteroid mining makes any sense.

 “I looked [at Planetary Resources’] advisory board, and I did not see a single mining engineer. That’s a big mistake,” warns Homer Hickam, whose escape from the coal mines of West Virginia to a career at NASA was chronicled in his 1998 book, Rocket Boys, and the 1999 film, “October Sky.”

 

Working below the Earth’s surface, then training shuttle astronauts to work in space gives Hickam a unique perspective on the question of space mining and whether we have the technology to actually do it. “When you start digging in the dirt – I don’t care if it’s on an asteroid, or the moon or West Virginia – you’d better have a mining engineer on board,” Hickam says. “It’s not as simple as you think it is.”

Even if an asteroid contained huge deposits of valuable metals like platinum or nickel, Hickam continues, “How are you going to carve that [metal] out of there? You are going to create a huge amount of debris in the process. And asteroids essentially have no gravity so it’s all going to go flying around.”

Instead, Hickam advocates mining the moon first for rare elements like Helium-3 that could potentially be used as fuel in fusion reactors. “At least you’ve got some gravity there,” he notes.

Read the full article, HERE.

LRO transitions from exploration to science

Images of the Apollo 11 landing site from the Lunar Reconnaissance Orbiter clearly show the descent stage, the footprints of Armstrong & Aldrin and various equipment they deployed in July 1969 (including Buzz Aldrin's brief stroll to the edge of the crater east of the lunar module Eagle. Beyond the usefulness to science, LRO's first images of all six manned landing sites provide a poignant reminder of the manned lunar exploration legacy of the United States. Before the close-orbiting precision supporting the LRO Narrow Angle Camera operated by Arizona State University, this clear evidence of human activity on the Moon remained just beyond the camera resolutions of unmanned cameras in the decades since the Apollo orbital mapping cameras. At less than one half meter per pixel resolution, the LROC NAC clearly reveal not simply the LM descent stages of the six Apollo mission but lunar rover tracks and the foot paths of the twelve astronauts who explored the lunar surface between 1969 and 1972 [NASA/GSFC/ASU].

Michael Braukus
NASA HQ

Nancy Neal Jones
NASA GSFC

The United States' Lunar Reconnaissance Orbiter (LRO) will complete the exploration phase of its mission on September 16, after a series of successes that added to the transformation of our understanding of Earth's nearest neighbor.

LRO completed a year-long exploration mission in a nearly circular polar orbit approximately 54 kilometers above the Moon's surface, comprehensively mapping the lunar surface in unprecedented detail, searching for resources and safe landing sites and measuring surface temperatures and radiation levels.

LRO's attentions will now turn from exploration objectives to scientific research as program management moves from NASA's Exploration Systems Mission Directorate (ESMD) to the Science Mission Directorate at the agency's headquarters in Washington.

"LRO has been an outstanding success," said Doug Cooke, associate administrator of the ESMD. "The spacecraft has performed brilliantly, and LRO science and engineering teams achieved all mission's objectives. The incredible data LRO gathered will provide discoveries about the moon for years to come."

LRO teams operating its instruments will continue forwarding data gathered during the last year to the Planetary Data System (PDS), which archives and distributes scientific information from NASA planetary missions, astronomical observations and laboratory measurements.

Thirty-five meter boulder among a sea of detail previously unseen in the two Constellation Regions of Interest on the Moon's Aristarchus Plateau. From LROC principal investigator Mark Robinson's report to the Third Annual NASA Lunar Science Institute Conference (Presentation - 17.5 mg PDF) [NASA/GSFC/Arizona State University].

By the time LRO achieves full mission success in March 2011, with data processed and released to the scientific community, it will have sent more information to the Planetary Data System than all previous planetary missions combined.

During its new phase of discovery, LRO will continue to map the moon for two to four more years.

"The official start of LRO's science phase should write a new and intriguing chapter in lunar research," said Ed Weiler, associate administrator for the Science Mission Directorate.

LRO was launched from Kennedy Space Center carrying a suite of seven instruments, June 18, 2009. After an initial Commissioning phase, LRO formally began a highly detailed survey of the Moon the following September.

Among results collected thus far from the mission are original observations of the Apollo landing sites; indications that permanently shadowed and nearby regions harbor water and hydrogen and other volatiles; observations that large areas in the permanently shadowed regions are colder than anywhere in the Solar System; detailed information about lunar terrain, and the first evidence of a globally distributed population of thrust faults, evidence the Moon has recently contracted and may still be shrinking.

Among other achievements, LRO captured high resolution pictures of Lunokhod 1, the first robotic lunar rover the Soviet Union used to explore withing Mare Imbrium in 1970, subsequently lost for nearly 40 years.

The rover was located to within 30 meters using the LROC Narrow Angle Camera, and this highly accurate position data enabled researchers to captured laser light bounced and clearly reflected back again from the French-built retro-reflector situated on the dormant Soviet lunar rover for the first time. This addition to the long incomplete laser reflector array left on the Moon by the U.S. and U.S.S.R. during the Apollo era should finally enable a precision in Earth-Moon distance measurements to within 3 cm, a target some cosmologists hope will aid in answering questions about "locality" of physical laws in the universe.

LRO also supported the Lunar Crater Observation and Sensing Satellite (LCROSS) impact, as the companion mission was sued to determined if the Moon's permanently shadowed craters harbor water ice, to select the Cabeus crater impact site and to observe the wispy fast expanding plume and to study an evolving temperature at the site soon after the LCROSS impact last October 9.

The previously eternally elusive comprehensive details of the "permanently darkened regions" inside and around the Moon's south pole, situated on the rim of 10 km-wide Shackleton crater. Though aspects of Shackleton interior were first unveiled by Japan's SELENE-1 (Kaguya), the suite of instruments on LRO are singularly equipped to eventually detail the entire Moon's surface, whether by Sun or starlight [Maria Zuber/NLSI/LOLA].

NASA's Goddard Space Flight Center (GSFC) in Greenbelt, Maryland built and will continue to manage LRO for the Exploration Systems Mission Directorate.

Michael Braukus - michael.j.braukus@nasa.gov
Nancy Neal Jones - nancy.n.jones@nasa.gov