MIT will lead a 375-million dollar mission to map the moon's interior and reconstruct its thermal history.

MIT mission to study moon's gravity
The Massachusetts Institute of Technology (MIT) will lead a 375-million dollar mission to map the moon's interior and reconstruct its thermal history.

According to a NASA announcement, the Gravity Recovery And Interior Laboratory (GRAIL) mission will be led by MIT professor Maria Zuber and will be launched in 2011.

The mission will put two separate satellites into orbit around the moon to precisely map variations in the moon's gravitational pull.

These changes will reveal differences in density of the moon's crust and mantle, and can be used to answer fundamental questions about the moon's internal structure and its history of collisions with asteroids.

The detailed information about lunar gravity will also significantly facilitate any future manned or unmanned missions to land on the moon.

Such data will be used to program the descent to the surface to avoid a crash landing and will also help target desirable landing sites.

Moreover, the mission's novel technology could eventually be used to explore other interesting worlds such as Mars.

"After the three-month mission is completed, we will know the lunar gravitational field better than we know Earth's," said Zuber, who is the head of the MIT's Department of Earth, Atmospheric and Planetary Sciences and the E.A. Griswold Professor of Geophysics.

She will be the principal investigator for the GRAIL mission.

Former astronaut Sally Ride, the first U.S. woman in space, will lead the project's educational outreach phase, which will include five live MoonKam cameras on each satellite that will be targeted by young students--especially middle-school girls--in their classrooms to get close-up still and video views of the moon's surface.

So far, even such fundamental questions as whether or not the moon has a separate, differentiated core, as Earth does, are unknown, Zuber says.

In addition to answering that question, the new mission should reveal details about lunar history, including the relative timing and effects of the myriads of huge impacts that created the craters and basins seen on the surface today.

The moon, with its airless, un-eroded surface, serves as a kind of Rosetta Stone for understanding the history of all the solar system's inner planets--Mercury, Venus, Earth and Mars--so the mission should also help to unlock secrets of the evolution of all these planets.

"The moon has the best-preserved record of the solar system's early history," Zuber says, while on other planets much of that record has been lost through erosion and other surface changes.

The technology used in the mission is a direct spin-off from the highly successful Gravity Recovery and Climate Experiment (GRACE) mission, which has been mapping Earth's gravitational field since 2002.

Using that technology made this a "low risk" mission for NASA because the necessary instruments had already been developed and tested.

As with that mission, GRAIL measurements of the gravitational field will come from very precise monitoring of changes in the distance between the two satellites.

The resulting measurements will map the moon's gravitational field up to 1,000 times more accurately than any previous mapping.

NASA selected the MIT-led mission from among two-dozen original proposals.

The GRAIL satellites will be built and operated by Lockheed Martin Space Systems of Denver, Colorado.

NASA's Jet Propulsion Laboratory in Pasadena, California will handle project management and developing the communications and navigation systems.

The mission's science team also includes David E. Smith of NASA Goddard Space Flight Center, who will be the deputy principal investigator, and other researchers from JPL, GSFC, the Carnegie Institution of Washington, the University of Arizona, the University of Paris and the Southwest Research Institute.

new kinds of biological research.( 'fire hose')

MIT has developed a new system for sorting cells that involves special "traps" in a silicone layer bonded to a microscope slide. Cells with specific properties are then levitated out of their traps using the pressure of a beam of targeted light from a low-cost laser. A flowing fluid then sweeps the selected cells off to a separate reservoir.

graduate student Joseph Kovac and Joel Voldman, associate professor of electrical engineering and computer science, have developed an inexpensive and easy method for sorting cells for microscope examination, using microfluidics and a laser beam "firehose."

Laser beam 'fire hose' used to sort cells


Separating particular kinds of cells from a sample could become faster, cheaper and easier thanks to a new system developed by MIT researchers that involves pushing up the cells with a laser beam "fire hose."

The system, which can sort up to 10,000 cells on a conventional glass microscope slide, could enable a variety of biological research projects that might not have been feasible before, its inventors say. It could also find applications in clinical testing and diagnosis, genetic screening and cloning research, all of which require the selection of cells with particular characteristics for further testing.

Joel Voldman, an associate professor in MIT's Department of Electrical Engineering and Computer Science, and Joseph Kovac, a graduate student in the department, developed the new system, which is featured as the cover story in the Dec. 15 issue of the journal Analytical Chemistry.

Present methods allow cells to be sorted based on whether or not they emit fluorescent light when mixed with a marker that responds to a particular protein or other compound. The new system allows more precise sorting, separating out cells based not just on the overall average fluorescent response of the whole cell but on responses that occur in specific parts of the cell, such as the nucleus. The system can also pick up responses that vary in how fast they begin or how long they last.

"We've been interested in looking at things inside the cell that either change over time, or are in specific places," Voldman said. Separating out cells with such characteristics "can't be done with traditional cell sorting."

For example, if cells differ in how quickly they respond to a particular compound used in the fluorescent labeling, the new system would make it possible to "select out the ones that are faster or slower, and see what's different," said Voldman, who also has appointments in MIT's Research Laboratory of Electronics and the Microsystems Technology Laboratories.

"It seems like that should be easy, but it isn't," he said. There are other ways of accomplishing the same kind of cell separation, but they require complex and expensive equipment, or are limited in the number of cells they can process.

The new system uses a simple transparent silicone layer bonded to a conventional glass microscope slide. Fabricated in the layer are a series of tiny cavities, or traps, in which cells settle out after being added to the slide in a solution. Up to 10,000 cells could be sorted on a single slide.

Looking through the microscope, either a technician or a computerized system can check each cell to determine whether it has fluorescence in the right area or at the right time to meet the selection criteria. If so, its position is noted by the computer. At the end of the selection process, all of the cells whose positions were recorded are then levitated out of their traps using the pressure of a beam of targeted light from a low-cost laser. A flowing fluid then sweeps the selected cells off to a separate reservoir.

The laser levitation of the cells acts like "a fire hose pushing up a beach ball," Voldman said. But the laser method is gentle enough that the living cells remain viable after the process is complete, allowing further biological testing.

Voldman and Kovac are continuing to refine the system, working on making it easier to use and on improving its ability to keep samples sterile. Voldman said that unlike expensive separation techniques such as optical tweezers, the new system could cost only a few thousand dollars. As a result, it could be employed in a variety of biological research laboratories or clinical settings, not just in big, centralized testing facilities.

The research was funded by the National Institutes of Health and the Singapore-MIT Alliance; Kovac is supported by an ASEE National Defense Science and Engineering Graduate Fellowship.