From: Planetary Science Institute
Posted: Friday, March 3, 2006
March 3, 2006
Committee on Science
US House of Representatives
Dear Chairman Boehlert and Members of the House Committee on Science,
I was shocked that after testifying before your Committee yesterday, the first thing Dr. Mary Cleave did upon returning to her office at NASA Headquarters was to cancel the Dawn Discovery mission. She made no mention of her intention to do this while testifying. At your meeting, missions were grouped into Flagship, medium and small, and all of your panelists accepted prioritization where they would delay or sacrifice larger missions in order to preserve basic research programs and smaller missions. In solar system exploration, Dawn is one of these small missions (the recently selected Juno mission falls into the medium category and the delayed Europa mission falls into the Flagship category). The Dawn PI, Dr. Christopher T. Russell, was notified of this action by NASA while attending his mother's funeral.
The Dawn mission was to be launched in June 2006 to rendezvous with two surviving protoplanets in the asteroid belt between Mars and Jupiter -the largest asteroids, Ceres and Vesta. Both objects were frozen in early stages of planet formation and evolution. Vesta accreted closer to the sun, was dry, and subsequently melted, resulting in the formation of a metallic core and basaltic volcanism on its surface. There is meteoritic evidence to suggest it's core may have produced a dynamo, like the Earth's. Ceres accreted at a greater distance from the sun and formed a rocky core with an ice rich mantle. Models suggest that Ceres may have a subsurface ocean, like Europa, which raises the question of whether life could have arisen beneath its surface.
Dawn was to be the first US science mission to use solar electric propulsion, first tested in interplanetary flight by the Deep Space 1 technology demonstration mission. Dawn represents another substantial European investment in a US solar system exploration mission. Germany is providing a double framing camera and Italy is providing a mapping spectrometer. The third instrument is a gamma- ray/neutron spectrometer provided by Los Alamos National Labs. Needless to say, the Europeans are furious with the US at this peremptory action by NASA.
Considering the concern raised at the hearing yesterday about the poor reputation of NASA as an international partner, which reflects poorly on the US, cancelling Dawn is a surprise at that level as well.
Eight months before launch (last October), technical issues were raised by NASA HQ regarding the tank for holding Xenon fuel and electronics related to the propulsion system. There was also considerable anger expressed at cost overruns, and NASA imposed a standdown and reduction in force of more than two-thirds at JPL and Orbital Sciences Corporation. At that time, the total mission cost was $371M of which NASA had already expended $255M, and JPL had requested an additional $40M to get to launch. Also, 98% of the hardware had been delivered, much of it already integrated into the spacecraft.
There are no longer any technical issues that would keep Dawn from successfully completing its mission, and in comparison to recent missions, Dawn cost overruns are not egregious, but because of NASA's standdown and reduction in force, the planned launch was delayed at least 14 months, unnecessarily increasing costs further. The Independent Assessment Team evaluating the technical and cost issues concluded (Jan. 27, 2006) that it "does not see any reason that the DAWN Project cannot be achieved within the identified cost and schedule changes proposed."
Along with continuing cuts to basic Research and Analysis programs, the cancellation of Dawn is programmatically bad and betrays a topsy-turvy set of priorities embraced by NASA's Science Mission Directorate that was displayed at the Committee hearing yesterday. Dawn should be reinstated.
Finally, cuts to basic Research and Analysis programs and the cancellation of Dawn are merely harbingers of things to come as NASA continues to raid its science programs to pay for under-funding and cost overruns associated with Human Space Flight. In a few years there may be little of these science programs left.
Mark V. Sykes,
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