Wednesday, April 28, 2004

MRO telescope is a design prototype for the Hubble

Pepita Ridgeway El Defensor Chieftain Reporter

The new 2.4-meter telescope going to the Magdalena Ridge Observatory was one of three designs to be a prototype for the Hubble Space Telescope.

When another design was chosen for Hubble, the plan was to use it for military test tracking, but funding for the project was cut off.

In 1999, congressional funding was made available to build a state of the art observatory on Magdalena Ridge. Plans for the observatory included an interferometer telescope array and a separate 2.4-meter telescope. The Department of Defense then donated the telescope to the MRO.

Dr. Eileen Ryan is project scientist and manager of the 2.4-meter telescope. Ryan gave a talk at New Mexico Tech this week about the scientific objectives of the project.

She said there are three objectives. The first is astronomical research with queue and remote observing. Second is Department of Defense mission support, missile tracking and satellite signatures, and third is to support and enhance New Mexico educational and public outreach.

"Budgetary concerns will determine the outcome of these goals," said Ryan.

Ryan's team completed the initial design review in November 2002. It will put out a Request for Proposal for the building, dome and pier by this fall and expect to start on the buildings by fall 2005. The telescope is expected to see "first light" in 2006.

Ryan said the 2.4-meter-diameter primary mirror has excellent measured performance.

"This is an expensive system that we are benefiting from," she added.

Once in operation, the telescope will be used mainly to study small bodies in the Solar system. It will also be used for asteroid character studies and near-Earth object studies.

"Collisions are fundamental processes in the Solar System and are not well understood. Also, Earth crossers are a potential hazard," said Ryan.

"Why Solar System studies? A 2.4-meter telescope is 'large' in this context. Collisional Studies is a competitive research area in New Mexico," said Ryan.

Ryan explained that New Mexico is a "niche" area where institutionally dedicated 2-meter class telescope time is difficult to obtain, thus enhancing funding opportunities for the project.

Because of the 2.4-meter class aperture, the telescope is ideal for observing very small objects less than 1 kilometer in diameter. The team of scientists working on the project will be conducting extra solar planet detection, selected image reconstruction, astrophysical survey studies and lightning sprite observation.

"There is thrilling observation potential," said Ryan.

Already, several external universities and organizations are looking to use the telescope for their specific areas of interest and the project has its first science proposal funded by NASA at $251,000. The NASA Ames Project studies near-Earth object hazards.

The Department of Defense is also very interested in any object that has a potential collision course with Earth.

Ryan said that if a large enough asteroid impacts the Earth, it could disturb the climate on a global scale, injecting large quantities of dust into the stratosphere, decreasing temperatures globally.

The critical diameter of an impacting asteroid would start in the 1- to 2-kilometer range.

The telescope will be used to mitigate near-Earth object hazards via physical characterization studies.

One of the complications, Ryan said, is that porosity of an asteroid can affect its collisional outcomes. The question arises as to how much energy is needed to completely disperse a rubble pile to prevent it from reassembling due to its own gravity.

Ryan did tests using balls of ice at the EMRTC Impact Chamber in Socorro. A solid ball of ice broke into small pieces, while a ball of commercial ice pieces remained 60 percent intact under the same impact conditions. She said numerical and laboratory tests show that porous objects can require 100 times more energy to disrupt and shatter.

Ryan said that most large asteroids studied are porous in nature.

"Air spaces don't propagate stress, strain and shock waves, therefore, there is a more destructive outcome," said Ryan.

"We need to know more about asteroids' composition, internal structure and size."

Photometric and spectroscopic instruments attached to the telescope will be used to determine the physical characterization of asteroids such as shape and composition. A more accurate strength parameter can be determined, using the telescope instruments.

"Without enough warning time, not much can be done. We need follow-up programs in tandem with discovery programs," said Ryan.

Ryan said if not enough energy is used to disrupt the near-Earth object, the asteroid may be broken up into smaller pieces, causing a shotgun effect rather than a single bullet.

"There is more emphasis now on physical characterization studies," said Ryan.

Ryan concluded her talk by saying, half jokingly, "The Department of Defense and science can work hand in hand to save the world from destruction."

She added, "The telescope has exciting research potential, important Department of Defense partnerships and a competitive research mission that is still student accessible."

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