Posted on by Anne Minard

LCROSS Gets Set for Lunar Smash-Up

Artist's rendering of the Lunar Reconnaissance Orbiter and LCROSS at separation, courtesy of NASA

 

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Early next week, a NASA craft designed to hammer the moon will travel from California to the Kennedy Space Center — one step closer to the planned April 24 launch. The Lunar Crater Observation and Sensing Satellite, or LCROSS, will hitch a ride to the moon aboard the Lunar Reconnaissance Orbiter. The orbiter carries a suite of instruments for taking detailed temperature readings, looking at the effects of radiation on the lunar surface and scoping out good landing sites for future missions, among other science goals.

Sound a little intrusive?  That’s nothing compared to the 15-foot (4.5-meter) deep, 100-foot (30 meter) wide hole that LCROSS will gouge into the lunar surface.

The whole package will spend about four days in transit to the moon, and then will orbit for several months, searching for the best impact site and setting up a prime trajectory. Around the first of August, LCROSS will approach the moon in two parts. First, it will fire its car-sized rocket to separate from the orbiter, then quickly shed the rocket and send it pummeling into the moon — at a whopping 5,600 miles (9,000 km) per hour. The target is the permanently shadowed floor in one of the North Pole’s craters, where ice is most likely to be hiding. The impact is expected to dislodge 220 tons of material from the lunar surface. Debris will fly as far as 30 miles (50 km) from the impact site, providing a Deep-Impact-style explosion that should be visible with amateur telescopes on Earth.

Then, the LCROSS satellite itself will fly through the plume on a collision course with the lunar surface, sending information to Earth until the moment of its own demise. The Lunar Reconnaissance Orbiter will be watching, along with India’s lunar orbiter, called Chandrayaan-1, Japan’s Kaguya (SELENE) and a host of Earth-bound professional telescopes. The sweet spot for observing the impact will be just after sunset in Hawaii, and possibly on the western coasts of the United States and South America — with countries along the moon’s course catching the aftermath.

Hints of water were sent to Earth in the 1990s, when the Naval Research Laboratory’s Clementine mission detected hydrogen signals at the lunar poles. The data did not reveal whether the element is contained in water or another hydrogen-bearing compound, such as hydrated minerals or hydrocarbons. LCROSS is the fourth mission to aim for the moon’s surface in the past decade. NASA’s 1999 impact with the Lunar Prospector failed to dislodge detectable water ice. The European Space Agency’s SMART-1 pummeled the lunar surface in 2006, while telecopes all over the world took data on the ejecta. India’s Moon Impact Probe detached from Chandrayaan-1 and crashed into the moon in October, with a goal of analyzing lunar dust and especially to find Helium 3, an isotope rare on Earth which could hold value for energy production. LCROSS will make the first definitive investigation for water within a permanently shadowed crater, the most likely place where it wouldn’t have evaporated over the moon’s history.

The $79 million, cost-capped mission is unusual because it utilizes commercially available technology for some of its software and scientific instruments. LCROSS could serve as a model for future missions that employ available technology, rather than relying on designs built from scratch, said Jonas Dino, a NASA spokesman at Ames Research Center in Moffett Field, California.

Finding water on the moon would boost its usefulness for supporting infrastructure. The moon could, for example, serve as a launching site for manned exploration of Mars or destinations beyond. The moon’s gravity, just one-sixth the strength of Earth’s, would allow the use of much smaller rockets to go the same distance as missions from Earth. Hydrogen from the lunar surface could also be used in making rocket fuel, which would cut costs for space exploration.

Sources: LCROSS website and interviews with NASA spokesmen Grey Hautaluoma, in Washington, D.C. and Jonas Dino in California.

Posted on by Anne Minard

Next-Generation Telescope Gets Team

Artist's rendering of the Giant Magellan Telescope and support facilities at Las Campanas Observatory, Chile, high in the Andes Mountains. Photo by Todd Mason/Mason Productions

 

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Astronomy organizations in the United States, Australia and Korea have signed on to build the largest ground-based telescope in the world – unless another team gets there first. The Giant Magellan Telescope, or GMT, will have the resolving power of a single 24.5-meter (80-foot) primary mirror, which will make it three times more powerful than any of the Earth’s existing ground-based optical telescopes. Its domestic partners include the Carnegie Institution for Science, Harvard University, the Smithsonian Institution, Texas A & M University, the University of Arizona, and the University of Texas at Austin. Although the telescope has been in the works since 2003, the formal collaboration was announced Friday.

Charles Alcock, director of the Harvard-Smithsonian Center for Astrophysics, said the Giant Magellan Telescope is being designed to build on the legacy of a rash of smaller telescopes from the 1990s in California, Hawaii and Arizona. The existing telescopes have mirrors in the range of six to 10 meters (18 to 32 feet), and – while they’re making great headway in the nearby universe – they’re only able to make out the largest planets around other stars and the most luminous distant galaxies.

With a much larger primary mirror, the GMT will be able to detect much smaller and fainter objects in the sky, opening a window to the most distant, and therefore the oldest, stars and galaxies. Formed within the first billion years of the Big Bang, such objects reveal tantalizing insight into the universe’s infancy.

Earlier this year, a different consortium including the California Institute of Technology and the University of California, with Canadian and Japanese institutions, unveiled its own next-generation concept: the Thirty Meter Telescope. Whereas the GMT’s 24.5-meter primary mirror will come from a collection of eight smaller mirrors, the TMT will combine 492 segments to achieve the power of a single 30-meter (98-foot) mirror design.

In addition, the European Extremely Large Telescope is in the concept stage.

In terms of science, Alcock acknowledged that the two telescopes with US participation are headed toward redundancy. The main differences, he said, are in the engineering arena.

“They’ll probably both work,” he said. But Alcock thinks the GMT is most exciting from a technological point of view. Each of the GMT’s seven 8.4-meter primary segments will weigh 20 tons, and the telescope enclosure has a height of about 200 feet. The GMT partners aim to complete their detailed design within two years.

The TMT’s segmented concept builds on technology pioneered at the W.M. Keck Observatory in Hawaii, a past project of the Cal-Tech and University of California partnership.

Construction on the GMT is expected to begin in 2012 and completed in 2019, at Las Campanas Observatory in the Andes Mountains of Chile. The total cost is projected to be $700 million, with $130 million raised so far. 

Artists concept of the Thirty Meter Telescope Observatory. Credit: TMT
Artists concept of the Thirty Meter Telescope Observatory. Credit: TMT

Construction on the TMT could begin as early as 2011 with an estimated completion date of 2018. The telescope could go to Hawaii or Chile, and final site selection will be announced this summer. The total cost is estimated to be as high as $1 billion, with $300 million raised at last count.

 

Alcock said the next generation of telescopes is crucial for forward progress in 21st Century astronomy.

“The goal is to start discovering and characterizing planets that might harbor life,” he said. “It’s very clear that we’re going to need the next generation of telescopes to do that.”

And far from being a competition, the real race is to contribute to science, said Charles Blue, a TMT spokesman.

“All next generation observatories would really like to be up and running as soon as possible to meet the scientific demand,” he said.

In the shorter term, long distance space studies will get help from the James Webb Space Telescope, designed to replace the Hubble Space Telescope when it launches in 2013. And the Atacama Large Millimeter Array (ALMA), a large interferometer being completed in Chile, could join the fore by 2012.

Sources: EurekAlert and interviews with Charles Alcock, Charles Blue