Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

2 THEMIS probes redirected to moon to study magnetosphere, solar wind interactions

28.10.2010
New mission, ARTEMIS, begins science operations in Lagrange-point parking orbit

Two micro-satellites originally launched into Earth's orbit in 2007 by NASA have been redirected by University of California, Berkeley, scientists toward new orbits around the moon, extending study of the earth and moon's interaction with the solar wind.

The second of the two probes settled into a temporary "Lagrange-point" orbit on Friday, Oct. 22, inaugurating science operations for a new mission dubbed ARTEMIS – Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon's Interaction with the Sun.

Lagrange points are places where the gravity of Earth and the moon balance, creating a sort of gravitational parking lot for spacecraft. The two probes will remain there for six months before transitioning to their final, lunar orbits.

Over the next several years, ARTEMIS will help space scientists understand how the earth's magnetosphere is shaped by the strong solar wind at the distance of the moon and also how the moon's own tiny magnetic field interacts with the solar wind. Using simultaneous measurements of particles and electric and magnetic fields from two locations, ARTEMIS will provide the first three-dimensional perspective of how energetic particle acceleration occurs near the moon's orbit, in the distant magnetosphere, and in the solar wind.

"We currently know very little regarding the space environment of the moon, despite a number of existing and planned observatories there," said Vassilis Angelopoulos, principle investigator for the ARTEMIS mission and a professor of space physics at UCLA. "ARTEMIS is on stable orbits and can provide valuable information regarding the space environment, especially during the approaching solar maximum, as well as fully explore the earth's environment at lunar distances for the first time."

The two probes were originally part of NASA's five-probe THEMIS (Time History of Events and Macroscale Interactions during Substorms) mission, built and operated by UC Berkeley to orbit Earth and determine how storms in the earth's magnetic field disturb the colorful auroras in the Northern and Southern hemispheres.

THEMIS completed is primary mission in 2008 when Angelopoulos announced, "We discovered what makes the Northern Lights dance." The THEMIS team then proposed that the two outermost of the five probes use their extra fuel to propel themselves, via complex maneuvers around the moon and Earth, into lunar orbits – the first two-satellite mission to the moon. The maneuvers would also save the solar-powered spacecraft, which were spending more and more time in the earth's shadow and, for lack of power, in danger of freezing to death.

After approval from NASA, Angelopoulos and his UC Berkeley team, which operates the fleet of satellites from the campus's Space Sciences Laboratory (SSL), began to reposition the two probes on July 20, 2009. The first probe (P1) settled into an orbit around the L2 Lagrange point, located on the far side of the moon, on Aug. 25, 2010, and is now joined by the second (P2) in orbit around the L1 Lagrange point between Earth and moon.

"ARTEMIS is going where no spacecraft have gone before," said Manfred Bester, director of operations at SSL. "We are exploring the Earth-moon Lagrange points for the first time."

Because the Lagrange points lie just outside Earth's magnetosphere, they are excellent places from which to study the solar wind. Particle and field sensors onboard the ARTEMIS probes have access to solar wind streams and storm clouds as they approach Earth, a possible boon to space weather forecasters. Moreover, working from opposite Lagrange points, the two spacecraft will be able to measure solar wind turbulence on scales never sampled by previous missions.

"ARTEMIS is going to give us a fundamental new understanding of the solar wind," predicted David Sibeck, ARTEMIS project scientist at the Goddard Space Flight Center in Maryland.

ARTEMIS will also explore the moon's plasma wake – a turbulent cavity carved out of the solar wind by the moon itself, akin to the wake just behind a speedboat. Sibeck called this "a giant natural laboratory filled with a whole zoo of plasma waves waiting to be discovered and studied."

Plasmas are hot, ionized clouds of gas that can carry electromagnetic and electrostatic waves.

Another target of the ARTEMIS mission is Earth's magnetotail. Like a wind sock at an airport, Earth's magnetic field is elongated by the action of the solar wind, forming a tail that stretches to the orbit of the moon and beyond. Once a month around the time of the full moon, the ARTEMIS probes will follow the moon through the magnetotail.

"We are particularly hoping to catch some magnetic reconnection events," says Sibeck. "These are explosions in Earth's magnetotail that mimic solar flares, albeit on a much smaller scale."

ARTEMIS might even see giant 'plasmoids' accelerated by the explosions hitting the moon during magnetic storms. Plasmoids are self-contained balls of plasma and magnetic field that can carom off reconfiguring planetary magnetic fields in space like billiard balls.

These far-out explorations may have down-to-Earth applications, Angelopoulos said. Plasma waves and reconnection events pop up on Earth, such as in experimental fusion chambers. Fundamental discoveries by ARTEMIS could help advance research in the area of clean renewable energy.

After six months at the Lagrange points, ARTEMIS will move in closer to the moon, at first only 100 kilometers from the surface, but eventually even closer. From point-blank range, the spacecraft will look to see what the solar wind does to a rocky world when there is no magnetic field to protect it.

"Earth is protected from solar wind by the planetary magnetic field," explained Angelopoulos. "The moon, on the other hand, is utterly exposed. It has no global magnetism."

Studying how the solar wind electrifies, alters and erodes the moon's surface could reveal valuable information for future explorers and give planetary scientists a hint of what's happening on other unmagnetized worlds around the solar system.

Orbiting the moon is notoriously tricky because of irregularities in the lunar gravitational field. Enormous concentrations of mass – mascons – hide just below the surface and tug on spacecraft in unexpected ways, causing them over time to veer out of orbit, Angelopoulos said. ARTEMIS will mitigate this problem using highly elongated orbits, ranging from tens of kilometers to 18,000 kilometers.

"We'll zip by the lunar surface for a brief time each orbit," explained Angelopoulos. "Most of the time we'll linger 18,000 kilometers away where we can continue our studies of the solar wind at a safe distance. But over several years, even the sparse low-altitude measurements add up to a sizeable dataset."

ARTEMIS will work in tandem with current missions, such as NASA's Lunar Reconnaissance Orbiter, LADEE (Lunar Atmosphere and Dust Environment Explorer) and Grail (Gravity Recovery and Interior Laboratory), and Chang'e 2, a Chinese unmanned probe, to prepare the ground for increased robotic exploration of the moon by future U.S. missions, including the international lunar network.

Robert Sanders | EurekAlert!
Further information:
http://www.berkeley.edu

More articles from Physics and Astronomy:

nachricht NASA's fermi finds possible dark matter ties in andromeda galaxy
22.02.2017 | NASA/Goddard Space Flight Center

nachricht Tune your radio: galaxies sing while forming stars
21.02.2017 | Max-Planck-Institut für Radioastronomie

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Positrons as a new tool for lithium ion battery research: Holes in the electrode

22.02.2017 | Power and Electrical Engineering

New insights into the information processing of motor neurons

22.02.2017 | Life Sciences

Healthy Hiking in Smart Socks

22.02.2017 | Innovative Products

VideoLinks
B2B-VideoLinks
More VideoLinks >>>