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Status Report: NASA MESSENGER Passes the Billion-Mile Mark!

Wednesday, March 29, 2006

On March 23 MESSENGER reached the one-billion mile mark, placing the spacecraft about one-fifth of the way toward its destination to orbit Mercury. On that same day, in the early morning hours (UTC), the spacecraft's distance from the Sun was about the same as the Earth's distance to the Sun. "One billion miles and the team and spacecraft are doing well," says Mission Operations Manager Mark Holdridge of the Johns Hopkins Applied Physics Laboratory (APL), where the spacecraft is operated and where it was designed and built.

The MESSENGER spacecraft performed its final "flop" maneuver for the mission on March 8, pointing the back side of the spacecraft to the Sun until June 2006. This rotation about the X-axis is performed whenever the solar distance increases beyond approximately 0.95 astronomical units (AU), nearly the distance between the Earth and the Sun. At this distance, the solar arrays do not generate enough power to operate all spacecraft components simultaneously, including instruments and heaters. The "flop" is performed to heat the back side of the spacecraft with the Sun. A "flip" maneuver reverses the effect of the "flop" maneuver by pointing the sunshade toward the Sun. This solar heating reduces the need for multiple onboard heaters, providing the necessary power until the spacecraft is closer to the Sun again. Previous flip, flop, and flip maneuvers were performed on March 8, 2005, June 14, 2005, and September 7, 2005. The spacecraft is scheduled to flip back toward the Sun on June 21.

Even though the MESSENGER spacecraft is years away from entering its final destination of orbiting Mercury, the mission Science Team is already very busy collecting scientific data and sharing it with the larger scientific community. Those plans and results are now available on the team's new Web site: http://messenger.jhuapl.edu/soc/index.html.

For a complete look at MESSENGER's journey through the inner solar system, visit the Mission Design section of the Web site at http://messenger.jhuapl.edu/the_mission/mission_design.html.

To see where MESSENGER is now, visit http://messenger.jhuapl.edu/whereis/index.php.

More: NASA -Status Report on MESSENGER

NASA Reinstates the Dawn Mission

Wednesday, March 29, 2006

NASA senior management announced a decision Monday to reinstate the Dawn mission, a robotic exploration of two major asteroids. Dawn had been canceled because of technical problems and cost overruns.

The mission, named because it was designed to study objects dating from the dawn of the solar system, would travel to Vesta and Ceres, two of the largest asteroids orbiting the sun between Mars and Jupiter. Dawn will use an electric ion propulsion system and orbit multiple objects.

The mission originally was approved in December 2001 and was set for launch in June 2006. Technical problems and other difficulties delayed the projected launch date to July 2007 and pushed the cost from its original estimate of $373 million to $446 million. The decision to cancel Dawn was made March 2, 2006, after about $257 million already had been spent. An additional expenditure of about $14 million would have been required to terminate the project.

The reinstatement resulted from a review process that is part of new management procedures established by NASA Administrator Michael Griffin. The process is intended to help ensure open debate and thorough evaluation of major decisions regarding space exploration and agency operations.

"We revisited a number of technical and financial challenges and the work being done to address them," said NASA Associate Administrator Rex Geveden, who chaired the review panel. "Our review determined the project team has made substantive progress on many of this mission's technical issues, and, in the end, we have confidence the mission will succeed."

The Dawn decision document will be available on the Web at:http://www.nasa.gov/formedia

Story Credit: NASA-Erica Hupp/Dean Acosta

Mars Reconnaissance Orbiter Successfully Enters Orbit Around Mars!

Friday, March 10, 2006

Celebration photo of the team
Mars Reconnaissance Orbiter Successfully Enters Orbit Around Mars!

Mars Reconnaissance Orbiter mission manager Jim Graf raises his arms in celebration of the orbiter's successful entry into orbit around Mars. Behind him is Jet Propulsion Laboratory Director Dr. Charles Elachi, giving the "thumbs up."

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Credit: NASA
With a crucially timed firing of its main engines, NASA's new mission to Mars successfully put itself into orbit around the red planet.

The spacecraft, Mars Reconnaissance Orbiter, will provide more science data than all previous Mars missions combined.

Signals received from the spacecraft at 2:16 p.m. Pacific Time on 10 March 2006, after it emerged from its first pass behind Mars set off cheers and applause in control rooms at NASA's Jet Propulsion Laboratory, Pasadena, Calif., and at Lockheed Martin Space Systems, Denver.

"This is a great milestone to have accomplished, but it's just one of many milestones before we can open the champagne," said Colleen Hartman, deputy associate administrator for NASA's Science Mission Directorate. "Once we are in the prime science orbit, the spacecraft will perform observations of the atmosphere, surface, and subsurface of Mars in unprecedented detail."

The spacecraft traveled about 500 million kilometers (310 million miles) to reach Mars after its launch from Florida on Aug. 12, 2005. It needed to use its main thrusters as it neared the planet in order to slow itself enough for Mars' gravity to capture it. The thruster firing began while the spacecraft was still in radio contact with Earth, but needed to end during a tense half hour of radio silence while the spacecraft flew behind Mars.


More: NASA -Robotic NASA Craft Begins Orbiting Mars for Most-Detailed Exam

NASA's Cassini Discovers Potential Liquid Water on Enceladus

Thursday, March 9, 2006

Enceladus
Plumes of icy material extend above the southern polar region of Saturn's moon Enceladus as imaged by the Cassini spacecraft in February 2005. The monochrome view is presented along with a color-coded version on the right. The latter reveals a fainter and much more extended plume component.

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Credit: NASA/JPL/SSI
NASA's Cassini spacecraft may have found evidence of liquid water reservoirs that erupt in Yellowstone-like geysers on Saturn's moon Enceladus. The rare occurrence of liquid water so near the surface raises many new questions about the mysterious moon.

"We realize that this is a radical conclusion --that we may have evidence for liquid water within a body so small and so cold," said Dr. Carolyn Porco, Cassini imaging team leader at Space Science Institute, Boulder, Colo. "However, if we are right, we have significantly broadened the diversity of solar system environments where we might possibly have conditions suitable for living organisms."

High-resolution Cassini images show icy jets and towering plumes ejecting large quantities of particles at high speed. Scientists examined several models to explain the process. They ruled out the idea that the particles are produced by or blown off the moon's surface by vapor created when warm water ice converts to a gas. Instead, scientists have found evidence for a much more exciting possibility -- the jets might be erupting from near-surface pockets of liquid water above 0 degrees Celsius (32 degrees Fahrenheit), like cold versions of the Old Faithful geyser in Yellowstone.

In the spring of 2008, scientists will get another chance to look at Enceladus when Cassini flies within 350 kilometers approximately 220 miles), but much work remains after Cassini's four-year prime mission is over.

Mission scientists report these and other Enceladus findings in this week's issue of Science.

More: NASA - Potential Liquid Water on Enceladus

Dawn Mission Killed

Friday, March 3, 2006

Dawn mission
The mission would have studied the asteroids Ceres and Vesta, both relics from the early solar system

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Artist's impression: W Hartmann/JPL/NASA
In early February, Dawn principal investigator Christopher Russell, at the University of California Los Angeles, said "We were going full bore toward launch, running as fast as we could. We saw the finish line in sight and then someone shot the gun and said we're cancelling the race for a bit."

Apparently the mission was stopped after a US congressional hearing on NASA's science budget, reports NASAWatch.com, a website run by former NASA employee Keith Cowing.

Both asteroids were thought to be remnants of the first objects formed in the solar system. But they show mysterious differences in their structures – Vesta has melted and separated into layers, while Ceres has not. Dawn was to probe these differences, using close-range scrutiny.

The decision to cancel the mission came after ,more than a month, the agency was expected to complete an extensive review of the mission's progress. In October 2005, NASA ordered Dawn managers to stop work on the mission, citing excessive technical problems and a budget overrun.

More: Dawn asteroid mission killed.
Story Credit: NewScientist.com news service; Kimm Groshong

Deep Impact Team Reports First Evidence of Cometary Ice

Friday, March 3, 2006

Comet Tempel 1, which created a flamboyant Fourth of July fireworks display in space last year, is covered with a small amount of water ice. These results, reported by members of NASA’s Deep Impact team in an advanced online edition of Science, offer the first definitive evidence of surface ice on any comet.

“We have known for a long time that water ice exists in comets, but this is the first evidence of water ice on comets,” said Jessica Sunshine, Deep Impact co-investigator and lead author of the Science article. Tempel I A chief scientist with Science Applications International Corporation who holds three Brown University degrees, Sunshine said the discovery offers important insight into the composition of comets – small, Sun-orbiting space travelers that are believed to be leftovers from the formation of the solar system.

“Understanding a comet’s water cycle and supply is critical to understanding these bodies as a system and as a possible source that delivered water to Earth,” she said. “Add the large organic component in comets and you have two of the key ingredients for life.”

More: NASA - Deep Impact Team Reports First Evidence of Cometary Ice