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Post by Chicago Astronomer Joe on Nov 22, 2005 2:20:56 GMT -6
Exploring Asteroids Ceres and Vesta
Dawn's goal is to characterize the conditions and processes of the solar system's earliest epoch by investigating in detail two of the largest protoplanets remaining intact since their formations. Ceres and Vesta reside in the extensive zone between Mars and Jupiter together with many other smaller bodies, called the asteroid belt. Each has followed a very different evolutionary path constrained by the diversity of processes that operated during the first few million years of solar system evolution.
Post by Chicago Astronomer Joe on Nov 22, 2005 2:26:59 GMT -6
Slow Down Order on the DAWN Mission
In mid-October, the Dawn mission team was asked by NASA Headquarters to cease all work except that which was critical to maintaining the viability of the Dawn mission to launch on a delayed schedule, still achieving all of its scientific objectives. This action was taken in response to concerns about the availability of funding in FY2006 to cover any problems that might arise during environmental and performance testing, particularly with regard to several pieces of subsystem hardware perceived to have experienced significant problems. The chief items of concern are the Power Processing Units (PPUs) that provide the high voltage power to the thrusters in the ion propulsion system, one of the redundant Attitude Control Electronics (ACE) boxes, and the xenon tank.
Dawn is currently in the Assembly, Test and Launch Operations (ATLO) project phase. To date, nearly all the hardware has been successfully delivered to Orbital and integrated to the spacecraft. Delivery of the remaining PPU and ACE are pending. The solar array arrived and a deployment test was conducted at Orbital.
Post by Chicago Astronomer Joe on Mar 3, 2006 3:44:18 GMT -6
The Dawn mission has been canceled
Mary Cleave, who is the Associate Administrator for NASA's Science Mission Directorate, formally canceled the Dawn mission to Ceres and Vesta today. Dawn is a Discovery mission and was nearing completion (and only 8 months away from launch) when it was ordered to stand down in November because of some technical issues and cost overruns.
Ive made a few phone calls to some friends of mine about this mission, this is what Ive found out.
The mission has been delayed until Nov at the earlist. They are on Stand Down right now. Component problems and other things have delayed the mission. They must fly by next Nov to use Mars as a sling shot to the Asteroids.
As I find out more I'll let you know.
[glow=blue,2,300]Stargazer's Departing Nightly on a beam of light searching for the Ultimate Wisdom of the Universe [/glow]
Post by Chicago Astronomer Joe on Mar 6, 2006 19:57:54 GMT -6
NASA kills off troubled asteroid mission
22:06 04 March 2006
The Dawn mission to study two of the solar system's largest main-belt asteroids, Vesta and Ceres, has been cancelled, NASA confirmed on Friday. The mission had been in development for more than four years.
"As of Thursday we did make the decision to cancel Dawn," says Andrew Dantzler, director of NASA's planetary science division. In the end, the decision was not based on the quality of the mission's science, he told New Scientist: "It was based on fiscal responsibility."
The axing of the mission came about a month after the agency completed an extensive review of progress. In October 2005, NASA had ordered Dawn managers to stop work, citing excessive technical problems and a budget overrun.
Dantzler says the independent review board estimated the mission would come in about 20% over-budget, at a total cost of about $446 million. But there was significant uncertainty in that estimate stemming from 29 major issues, mostly technical, which the investigation board said would have to be resolved before Dawn could proceed.
Halfway there Overall, Dantzler says the vehicle was about 50% complete, with many components and subsystems already installed. "However, there are several significant major subsystems that were not installed", including the ion propulsion system. He says although all the previously-identified problems with the engine had been resolved, the system performed poorly during a final test.
Dantzler argues that despite the cancellation, some work will be salvaged from the Dawn mission. NASA is looking into using the spacecraft's hardware for other missions and future efforts to build ion propulsion engines will benefit from the lessons learned by Dawn engineers.
Post by Chicago Astronomer Joe on Mar 9, 2006 0:56:54 GMT -6
Cancellation of Dawn Mission on Hold Pending Review By NASA Administrator
Wednesday, March 8, 2006
Knowledgeable sources within NASA and the planetary science community report that the impending cancellation of the Dawn asteroid exploration mission has been put on hold pending a review by NASA Administrator Michael Griffin.
Last thursday, upon returning to her office from that morning's House Science Committee hearing on NASA's FY 2007 Science Budget, NASA's Associate Administrator for its Space Science Mission Directorate, Mary Cleave cancelled the Discovery "Dawn" mission.
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Post by Chicago Astronomer Joe on Mar 19, 2006 6:17:14 GMT -6
NASA reviews canceled asteroid mission
In an unusual move, NASA is reviewing a recent decision by an agency head to scrap a mission to orbit two asteroids.
The Dawn project was canceled on March 2, five months after it was put on standdown because of cost overruns and technical problems.
NASA's unusual step to review Dawn's termination came after the Jet Propulsion Laboratory in Pasadena, which manages the mission, presented new evidence, the space agency said in a statement.
It's the first time in recent memory that a NASA center has challenged a headquarters decision on a canceled mission, said NASA spokeswoman Erica Hupp.
The review, headed by NASA Associate Administrator Rex Geveden, will take into account JPL's new findings and the results from an independent team dispatched to evaluate the mission. A decision was expected as early as the end of the month.
NASA headquarters declined to say what the new evidence was and refused to make Geveden available for an interview. JPL spokeswoman Veronica McGregor said the center had no comment pending the review.
Post by Chicago Astronomer Joe on Mar 27, 2006 22:06:43 GMT -6
NASA Reinstates the Dawn Mission
Space and Earth science : March 27, 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."
Post by Chicago Astronomer Joe on Oct 31, 2006 20:21:34 GMT -6
Send your name to the Asteroids
NASA's campaign to send the nom de plumes of people from around the world into the heart of the asteroid belt ends Sat., Nov. 4.
Submitted names will be carried on board NASA's Dawn, the first spacecraft to travel between and scrutinize two distinct worlds. Mission scientists are confident Dawn observations of asteroid Vesta and dwarf planet Ceres will answer basic questions about the nature and composition of these celestial wanderers.
"How many chances do you get to fly into the very heart of the asteroid belt?" said Keyur Patel, Dawn project manager at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "When the craft is launched in June 2007, yours and the names of your loved ones can hitch along for the ride and be part of space exploration history."
Dawn will carry a silicon chip containing the names of asteroid, space and other enthusiasts from around the world. People may submit their names for this historic one-way mission by visiting JPL's Dawn Web site now through Nov. 4 at dawn.jpl.nasa.gov . More than 170,000 people have already signed up for the asteroid belt tour.
Following launch, Dawn will employ an ion engine to propel it during its more than four year, 3-billion-kilometer journey (1.9-billion miles) to its first target – asteroid Vesta. After months of detailed scientific observation of Vesta, Dawn's ion engine will fire up again, and send it on its way for a 2014 rendezvous with Ceres, recently anointed a "dwarf planet" by the International Astronomical Union.
"This campaign will allow people from around the world to become directly involved with Dawn, and through that, become familiar with the mission's science," said University of California Los Angeles professor Dr. Chris Russell, Dawn's principal investigator.
The Dawn mission is managed by JPL, a division of the California Institute of Technology in Pasadena, for NASA's Science Mission Directorate, Washington. The University of California Los Angeles is responsible for overall Dawn mission science. Orbital Sciences Corporation of Dulles, Virginia, designed and built the Dawn spacecraft.
Post by Chicago Astronomer Joe on Sept 27, 2007 20:04:47 GMT -6
Dawn Spacecraft Lifts Off
NASA's Dawn spacecraft is on its way to study a pair of asteroids after lifting off Thursday from the Cape Canaveral Air Force Station at 7:34 a.m. EDT.
Mission controllers at NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif., received telemetry on schedule at 9:44 a.m. indicating Dawn had achieved proper orientation in space and its massive solar array was generating power from the sun.
"Dawn has risen, and the spacecraft is healthy," said the mission's project manager Keyur Patel of JPL. "About this time tomorrow [Friday morning], we will have passed the moon's orbit."
During the next 80 days, spacecraft controllers will test and calibrate the myriad of spacecraft systems and subsystems, ensuring Dawn is ready for the long journey ahead.
"Dawn will travel back in time by probing deep into the asteroid belt," said Dawn Principal Investigator Christopher Russell, University of California, Los Angeles. "This is a moment the space science community has been waiting for since interplanetary spaceflight became possible."
Dawn's 3-billion-mile odyssey includes exploration of asteroid Vesta in 2011 and the dwarf planet Ceres in 2015. These two icons of the asteroid belt have been witness to much of our solar system's history. By using Dawn's instruments to study both asteroids, scientists more accurately can compare and contrast the two. Dawn's science instrument suite will measure elemental and mineral composition, shape, surface topography, tectonic history, and it will seek water-bearing minerals. In addition, the Dawn spacecraft and how it orbits Vesta and Ceres will be used to measure the celestial bodies' masses and gravity fields.
The spacecraft's engines use a unique, hyper-efficient system called ion propulsion, which uses electricity to ionize xenon to generate thrust. The 12-inch-wide ion thrusters provide less power than conventional engines but can maintain thrust for months at a time.