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Posted by on Dec 18, 2012 in Science |

Curiosities GRAIL probes after impact with the Moon

Curiosities GRAIL probes after impact with the Moon

Goodbye Ebb and Flow, and thank you very much for everything.

With these words he dismissed the probes David Lehman, GRAIL project manager. About 10:28 UTC occurred the first of the two impacts of ships on a crater near the moon’s north pole. Two almost simultaneous impacts that we can never see because it was a region with poor lighting, making it impossible that we could see the shock. A successful end, as this was stipulated that Ebb and Flow (as have been baptized) finished their mission, to perform more detailed gravity map of the Moon .

Members of the mission team estimates that the two ships were traveling at a speed of 1.7 km per second. Even without images, it is likely that both ships are broken upon impact, according to NASA, most of what remains of the two will be buried in shallow craters, craters in two weeks will be analyzed and photographed by the Lunar Reconnaissance Orbiter .

Top mission

GRAIL is the acronym for Gravity Recovery And Interior Laboratory, Discovery Program mission that began on September 10, 2011. That day, the probes were launched aboard the Delta II in a direct ride to the satellite would take much longer than usual.

The reason is the primary mission of GRAIL. I needed a low-energy trip to the satellite through the point-Tiera Lagange 1 Sol (about 4 months) to reduce the fuel used while protecting the instruments and could slow down the speed of the ship just in time where on the moon. Thus low orbit would reach 50 km. (Arrived at this stage of the mission to 55 km.) With a separation between them of about 175-225 km.

Mission and objectives

GRAIL was primarily designed to perform more detailed gravity map of the Moon. Both ships were able to transmit and receive telemetry and other facilities on Earth. That way they could measure the distance between the two and could obtain the gravitational field and the geological structure of the more detellada to date. Six were GRAIL main objectives:

  • Set limits on the size of the core of the moon.
  • Map the structure of the crust and lithosphere.
  • Determine the subsurface structure of impact craters and the origin of lunar mascons.
  • Knowing the structure of the innermost part of the Moon.
  • Understanding the asymmetric thermal evolution of the moon.
  • Determine the time evolution of the crust gaps and magma.


In August 2012 it was stipulated that ended the career of GRAIL. Finally, the mission has expanded over time. Initially, the phase “scientific” would last 90 days. Would then stipulated that a period of five days where the ship would be “out of service” to weigh on the moon in about 40 days or so.

It happened on 30 August this year was extended because the probes remained in good condition as well as having enough fuel. An extra mission that would last until December 3, where the orbits of the probes would come down to 23 kilometers. The result, to obtain more precise data, ie, the most detailed map of the moon’s gravity on the near side.

According to NASA, the data collected by GRAIL (over 100,000 photographs between the two probes) are summarized in:

  • A gravity map up to 100 times more detailed than we had before.
  • 1,000 times more detailed than the dark side of the moon.
  • Overall, the most detailed map we have of any Solar System body.
  • The discovery of a porous and thinner crust than previously thought.

Ebb and Flow, the name you were baptized both probes by school students Emily Dickinson (Montana), ended his journey on the south side of a mountain near the crater Goldschmidt. A mountain that has been given the name of Sally Ride in honor of the first U.S. woman astronaut in space who died this year. A mission with results that will be studied by scientists.

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