Two twin satellites Artemis in the moon's orbit

On Sunday, July 17, 2011, the first Artemis satellite flew in the moon's orbit to get its second new companion in less than a month. That's when the second Artemis satellite, designed by researchers at the University of California, Berkeley, USA, is also part of the mission of five NASA Themis satellites to be dropped into orbit. Moon permanently after a tortuous journey, lasting 2 years, from its original orbit is Earth.

The first Artemis satellite was launched into orbit around the moon's equator on June 27, 2011. If all goes well, the second probe satellite will be launched into the same orbit, but according to in the opposite direction, on Sunday afternoon, July 17, 2011. These two Artemis satellites will immediately begin the first observation on the lunar surface: the moon's magnetic field and the surrounding magnetic environment.

The first satellite Artemis flies in the moon's orbit

" With two Artemis satellites traveling in the same orbit but in opposite directions, we will get a three-dimensional image of the magnetic structure near and on the moon ," according to Vassilis Angelopoulos, principal researcher in the mission of satellites Themis and Artemis, and professor of space physics at UCLA University, USA. " Artemis satellite will carry out completely new scientific missions, as well as re-using existing satellites to save public funds ."

" These are the most fully equipped satellites that have been to the moon ," said David Sibeck, project scientist Themis and Artemis, at the Goddard Space Center (GSFC) in Maryland, USA. " This is the first time we have observed the moon from two opposite directions, thanks to two twin satellites, and this will be the main component of our Moon's overall research program ."

The transition to the moon's orbit will be handled by engineers at the Space Science Laboratory (SSL), UC Berkeley, USA: controlling the mission of the Themis satellite (Time, the the sequence of events and macroscopic interactions of small storms) and Satellite Artemis (acceleration, reconnection, chaos, and electrodynamics of the Moon's interaction with the sun).

" We are following the schedule we have committed ," said Manfred Bester, executive director of the Space Science Laboratory (SSL).

05 Themis satellites were launched into space by NASA on February 17, 2007, to explore how magnetic storms at millions of miles per hour interact with the Earth's magnetic field in the far direction and opposite the surface of the earth. Within a year and a half, they found the main answer of the mission: Where and how the origins of the small storms in the Earth's magnetosphere, the appearance of dawn in the Arctic and Antarctica ?

The answer : The storms originate from deep within the sun's hidden shadow of the planet, at about a third of the distance to the moon, where the magnetic field captures, reconnects and unlocks an energy storm. but the hopper at the poles makes light in the air appear red and blue. Large storms can devastate satellites, grids and communication systems.

Mission completed, scientists want to redirect 2 of the 5 satellites Themis to the moon orbit to extend their magnetic research further into space. A key reason is that the two most distant satellites will soon stop working because, with so much time spent in the shadow of the sun, the solar cells of the Satellites will discharge .

To complete the new task, a team of researchers at UC Berkeley, the United States and Goddard, with the help of experts at the Jet Motion Laboratory in Pasadena, USA, proceeded to draw 150 expressions. exercise gear to save fuel, and to motivate two satellites Themis from earth orbit into temporary orbit around the Earth and Moon Lagrange points, which are points in space, with gravitational attraction The lead from the moon and the earth are the same. The transfer took about 18 months, after which Goddard colleagues kept two satellites in the Lagrange point trajectory for several months before the first satellite (P1) was transferred to the moon's orbit in June.

" It was a technical challenge, the first task we piloted on a moon orbit satellite but was not designed to go there ," according to Daniel Cosgrove, orbital control engineer. satellite, working at UC Berkeley University, USA. Control work is difficult. Satellite thrusters are small, only convenient for pushing down and to the side, while the satellites are constantly rotating, making the control more difficult.

Furthermore, the P1 satellite lost its spherical sensor in 2010, at the end of one of the four long wires protruding from the satellite to measure the electric field in space. The cause may be a tiny meteorite that cuts one-tenth of the 82-foot wire and breaks the spherical sensor, sending " small black orbs flying out through the solar system ", Bester to speak.

These 5 satellites have been built by a very talented team with great attention to detail, predicting that Artemis probes can survive for another 10 years, longer than 3 Defense The remaining Themis, which had repeatedly flown in and out of the Van Allen radiation belt of Earth's danger.

After the second satellite, P2, was launched into the Moon's orbit, two Artemis satellites would scan the lunar surface once for each orbit, and reach within a few dozen kilometers in a different belt. , 20 degrees above and below the equator, while recording the electric and magnetic fields, and ion concentrations.

" When the moon passes through the solar storm, the magnetic field embedded in rocks near the surface interacts with the magnetic field from the solar wind, while the Moon's surface itself absorbs solar wind particles. create a compartment behind it , "Angelopoulos said. " We can study complex interactions to learn more about the moon as well as the solar wind, from a vantage point between two single observation points that show for the first time a three-dimensional image of structure. dynamic structure . "

Sibeck notes: " NASA's stereo twin-ship, launched into space in 2006, has also provided a 3D view of the sun's magnetic field on a large scale. Satellite Themis and Artemis study the Micro processes, which we now know operate systems , "says Sibeck.

A task of satellite Artemis is to find plasmoids, which are hot spots of ionized gas or plasma.

" Themis satellite has shown recombinant magnetic evidence that pushes the hot spots of plasma both ways: to and from the Earth, and we want to discover how they work and how much energy , "Angelopoulos said. " Plasmoids can be tens of thousands of kilometers long ."

" Themis has found the cause and Artemis satellite will study the consequences, which can be massive and global," said Sibeck.

The satellite will also study the surface composition of the moon by recording the solar wind particles that reflect or scatter from the surface and ions escaping from the surface of the moon by the wind.

" These measurements can tell us about the properties of the moon's surface, from which we can deduce the formation and evolution of the surface of the moon over billions of years ," Angelopoulos said. .

2 Artemis satellites will join the reconnaissance spacecraft flying along NASA's moon orbit, which has been around the moon since 2009 to get high-resolution images and look for signs of ice. In September 2010, NASA plans to launch a satellite with two functions: gravity recovery and a multimedia lab, to map the moon's gravitational field in 2013, to launch the next Ladee planning: Study the moon atmosphere and explore the dust environment, to characterize the atmosphere of the moon and the dust environment there.

" Artemis satellite will provide the context for Ladee's mission ," Sibeck said.

Three other inactive satellites are still in orbit around the moon: two small satellites following Japan's moon orbit, Kaguya, has fallen to the moon's surface in 2009; India's Chandrayaan-1 satellite, too, lost contact with the Earth in 2009. The satellite follows China's second moon orbit, Chang Er 2 has left the moon to enter the inter-space. planet on June 8, 2011.