Countdown to Deep Impact

The rocks inside a crater on the Asteroid Eros, as imaged before impact with the NEAR spacecraft. Numerous small impacts on the asteroid show brown boulders visible interior to the less exposed (white) lip of the crater. False-color for emphasis.
Image Credit: NASA/Eros

NASA’s Deep Impact spacecraft has arrived in Florida to begin final preparations for a launch on Dec. 30, 2004. The spacecraft was shipped from Ball Aerospace & Technologies in Boulder, Colo., to the Astrotech Space Operations facility located near the Kennedy Space Center in Florida.

"Deep Impact has begun its journey to comet Tempel 1," said Rick Grammier, Deep Impact project manager at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. "First to Florida, then to space, and then to the comet itself. It will be quite a journey and one which we can all witness together."

The Deep Impact spacecraft is designed to launch a copper projectile into the surface of comet Tempel 1 on July 4, 2005, when the comet is 133.6 million kilometers (83 million miles) from Earth. When this 372-kilogram (820-pound) "impactor" hits the surface of the comet at approximately 37,000 kilometers per hour (23,000 miles per hour), the 1-by-1 meter projectile (39-by-39 inches) will create a crater that could be as large as a football field. Deep Impact’s "flyby" spacecraft will collect pictures and data of the event. It will send the data back to Earth through the antennas of the Deep Space Network. Professional and amateur astronomers on Earth will also be able to observe the material flying from the comet’s newly formed crater, adding to the data and images collected by the Deep Impact spacecraft and other telescopes. Tempel 1 poses no threat to Earth in the foreseeable future.

At Astrotech, Deep Impact was removed from its shipping container, the first of the numerous milestones to prepare it for launch. Later last week, the spacecraft began functional testing to verify its state of health after the over-the-road journey from Colorado. This will be followed by loading updated flight software and beginning a series of mission readiness tests. These tests involve the entire spacecraft flight system that includes the flyby and impactor, as well as the associated science instruments and the spacecraft’s basic subsystems.

Deep Impact probe. Image Credit:NASA

Next, the high gain antenna used for spacecraft communications will be installed. The solar array will then be stowed and an illumination test performed as a final check of its performance. Then, Deep Impact will be ready for fueling preparations. Once this is complete, the 976-kilogram spacecraft (2,152 pounds) will be mated atop the upper stage booster, the Delta rocket’s third stage. The integrated stack will be installed into a transportation canister in preparation for going to the launch pad in mid- December.

Once at the pad and hoisted onto the Boeing Delta II rocket, a brief functional test will be performed to re-verify spacecraft state of health. Next will be an integrated test with the Delta II before installing the fairing around the spacecraft.

Deep Impact mission scientists are confident that an intimate glimpse beneath the surface of a comet, where material and debris from the formation of the solar system remain relatively unchanged, will answer basic questions about the formation of the solar system and offer a better look at the nature and composition of these celestial wanderers.

Launch aboard the Boeing Delta II rocket is scheduled to occur on Dec. 30 from Launch Complex 17 at Cape Canaveral Air Force Station. The launch window extends from 2:39 to 3:19 p.m. Eastern Standard Time (11:39 a.m. to 12:19 p.m. Pacific Standard Time).

Related Web Pages

Great Impact: Part I: The Benefits of Hard Bodies
Great Impact: Part II: Much Ado about Nothing?
Great Impact: Part III: The Large and the Small
Great Impact: Part IV: On A Collision Course with Earth
Great Impact: Part V: Encore
Impact Hazards Website
NASA/JPL Near Earth Object Program
IAU Minor Planet Center