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Tag: GRAIL mission

  • NASA Probes Smash Into Moon Mountain as Planned

    NASA’s GRAIL project spacecrafts, Ebb and Flow, crash-landed on the surface of the moon yesterday afternoon. The impact had been pre-planned, and occurred as predicted at 5:28 pm December 17, 2012. The landing site has been named in honor of Sally Ride, the first U.S. woman in space and a member of the GRAIL mission team.

    “Sally was all about getting the job done, whether it be in exploring space, inspiring the next generation, or helping make the GRAIL mission the resounding success it is today,” said Maria Zuber, GRAIL principal investigator at the Massachusetts Institute of Technology. “As we complete our lunar mission, we are proud we can honor Sally Ride’s contributions by naming this corner of the moon after her.”

    The GRAIL probes were crashed into the moon at 1.7 kilometers per second (3,760 mph) because they had fulfilled their primary and extended missions, were low in orbit, and did not have enough fuel to be of any further use. The Sally K. Ride impact site, located on the southern face of a lunar mountain near Goldschmidt crater, was chosen to avoid the disturbance of U.S. and Russian historical sites scattered across the moon’s surface.

    The site was in shadow at the time of impact, so no images of the event were recorded. However, NASA‘s Lunar Reconnaissance Orbiter will be able to snap photos of the crash site in several weeks.

    During their time in orbit, Ebb and Flow collected data that allowed scientists to create the highest-resolution gravity map of any celestial body.

    “We will miss our lunar twins, but the scientists tell me it will take years to analyze all the great data they got, and that is why we came to the moon in the first place,” said David Lehman, GRAIL project manager at NASA’s Jet Propulsion Laboratory. “So long, Ebb and Flow, and we thank you.”

    NASA provided live interviews and analysis by the GRAIL team in the moments leading up to the mission’s destructive finale. A recording of the events can be seen below.

  • NASA Probes Prepare to Slam Into the Moon

    NASA Probes Prepare to Slam Into the Moon

    NASA‘s Gravity Recovery and Interior Laboratory (GRAIL) probes today completed a burn that irreversibly altered their orbit and have begun skimming the surface of the moon. Over the weekend, the probes, named Ebb and Flow, will orbit ever closer to the surface of the moon. On Monday, December 17, at around 5:28 pm EST the probes will slam into the side of a lunar mountain while traveling at approximately 3,760 miles per hour.

    “NASA wanted to rule out any possibility of our twins hitting the surface anywhere near any of the historic lunar exploration sites like the Apollo landing sites or where the Russian Luna probes touched down,” said David Lehman, GRAIL project manager at NASA’s Jet Propulsion Laboratory (JPL). “Our navigators calculated the odds before this maneuver as about seven in a million. Now, after these two successful rocket firings, there is zero chance.”

    The crash landing is a planned event, necessary because the probes’ low orbit and fuel levels make them useless for any further study. The impact will take place near the moon’s north pole, close to a crater named Goldschmidt. The area will be in shadow at the time, and no photos or video of the event are expected.

    NASA will, however, be live-streaming commentary of the event starting at 5 pm EST on Monday. The commentary will come from the control room at the JPL and will include interviews with the GRAIL team. It can be viewed on NASA TV or on the JPL Ustream channel.

    The probes began orbiting the moon on January 1, 2012. In their year of orbit, Ebb and Flow collected data that helped scientists create the highest-resolution gravity field map of any celestial body to date.

  • NASA to Crash GRAIL Probes Into the Moon

    NASA this week detailed its plans to crash two lunar-orbiting probes into the moon next week. On Monday, December 17 at 5:28 p.m., the probes, named Ebb and Flow, are part the Gravity Recovery and Interior Laboratory (GRAIL) project. They will descend and impact a lunar mountain near the moon’s north pole.

    The crash-landing is purposeful, as the probes’ low orbit and low fuel levels make it impossible for them to be of any further use for scientific studies. The probes have successfully completed their primary and extended science missions.

    Just last week, NASA revealed a gravity map of the moon that was based on GRAIL data taken by the probes. The map is the highest-resolution gravity field map of any celestial body to date, and will provide researchers with a better understanding of how Earth and other rocky planets formed.

    “It is going to be difficult to say goodbye,” said Maria Zuber, GRAIL principal investigator at the Massachusetts Institute of Technology. “Our little robotic twins have been exemplary members of the GRAIL family, and planetary science has advanced in a major way because of their contributions.”

    Ebb will be the fist probe to hit the moon’s surface, with Flow following 20 seconds later. The spacecrafts will be travelling at 1.7 kilometers per second (3,760 miles per hour) when they hit the surface. The area of the moon where the probes are expected to impact will be in shadow at the time of impact, so no images of the event are expected.

    Before their final flight, the probes will both empty their propellant tanks by firing their main engines. This will show exactly how much fuel each probe has remaining, helping NASA engineers improve computer models that predict fuel consumption for future missions. After the burn, the probes will skim the surface of the moon for several hours until the lunar mountain rises in front of them.

    “Our lunar twins may be in the twilight of their operational lives, but one thing is for sure, they are going down swinging,” said David Lehman, GRAIL project manager at NASA’s Jet Propulsion Laboratory. “Even during the last half of their last orbit, we are going to do an engineering experiment that could help future missions operate more efficiently.

    “Such a unique end-of-mission scenario requires extensive and detailed mission planning and navigation. We’ve had our share of challenges during this mission and always come through in flying colors, but nobody I know around here has ever flown into a moon mountain before. It’ll be a first for us, that’s for sure.”

  • Moon is Battered, Reveals New Gravity Map

    A new gravity map of Earth’s moon shows a record of billions of years of impacts on its surface. The new map, generated by NASA‘s Gravity Recovery and Interior Laboratory (GRAIL) mission, is now the highest resolution gravity field map of any celestial body. It will allow scientists to learn about the internal structure of the moon, its tectonic structures, volcanic landforms, basin rings, crater central peaks, and craters.

    “What this map tells us is that more than any other celestial body we know of, the moon wears its gravity field on its sleeve,” said Maria Zuber, GRAIL Principal Investigator at the Massachusetts Institute of Technology (MIT). “When we see a notable change in the gravity field, we can sync up this change with surface topography features such as craters, rilles or mountains.”

    The gravity map was created from data taken by two washing machine-sized spacecraft (GRAIL-A and GRAIL-B, or “Ebb” and “Flow”) orbiting the moon. The probes transmit radio signals to each other to precisely measure the distance between them while orbiting the moon. As they pass over areas of greater or lesser gravity on the moon, the distance between them shifts slightly.

    The probes also revealed that the bulk density of the moon’s highland crust is “substantially” lower than predicted. The density is, however, consistent with data from the Apollo missions in the 70s. This suggests that samples of the moon brought back by astronauts are a good representation of processes on the moon. The bulk composition of the moon is also similar to that of Earth, providing evidence for models that show the moon was formed from a giant impact with Earth in the early solar system.

    “We used gradients of the gravity field in order to highlight smaller and narrower structures than could be seen in previous datasets,” said Jeff Andrews-Hanna, a GRAIL scientist at the Colorado School of Mines. “This data revealed a population of long, linear gravity anomalies, with lengths of hundreds of kilometers, crisscrossing the surface. These linear gravity anomalies indicate the presence of dikes, or long, thin, vertical bodies of solidified magma in the subsurface. The dikes are among the oldest features on the moon, and understanding them will tell us about its early history.”

    (Image courtesy NASA/JPL-Caltech/MIT/GSFC)

  • Huge South Pole Moon Crater Could Hold Frozen Water

    The moon still holds some mysteries. One of those being whether or not there is any discernible amount of ice on the surface. While we have been to the moon, we have only visited a very small area. The way of knowing without actually going there are hit and miss too. For instance, the Japanese spacecraft Kaguya saw no discernible signs of ice within Shackleton Crater, but NASA’s LCROSS probe analyzed Cabeus Crater near the moon’s south pole and found it measured as much as 5 percent water by mass.

    The way they check this is by having a spacecraft illuminate the interior of the crater with infrared laser light, measuring how reflective it was. The scan of The crater’s floor was more reflective than that of other nearby craters, suggesting it had ice. “Water ice in amounts of up to 20 percent is a viable possibility,” study lead author Maria Zuber told SPACE.com. Don’t get your hopes up, though she cautioned. The amount of ice in Shackleton Crater “can also be much less, conceivably as little as zero.”

    Zuber noted that the measurements only look at a micron-thick portion of Shackleton Crater’s uppermost layer. “A bigger question is how much water might be buried at depth,” Zuber said, adding that NASA’s GRAIL mission will investigate that possibility. And with that possibility we get the reality of a permanent base on the moon. If there is water in massive amounts, which some suspect there could be. We would have the ability to make rocket fuel and potable water for human settlement.