Posted on 05/16/2005 8:35:53 AM PDT by RightWhale
Comet-hitting probe tweaks its course to target
NASA NEWS RELEASE Posted: May 15, 2005
Fifty-nine days before going head-to-head with comet Tempel 1, NASA's Deep Impact spacecraft successfully executed the second trajectory correction maneuver of the mission.
The burn further refined the spacecraft's trajectory, or flight path, and also moved forward the expected time of the Independence Day comet encounter so impact would be visible by ground- and space-based observatories.
The 95-second burn - the longest remaining firing of the spacecraft's motors prior to comet encounter -- was executed on May 4. It changed Deep Impact's speed by 18.2 kilometers per hour (11.3 miles per hour).
"Spacecraft performance has been excellent, and this burn was no different," said Rick Grammier, Deep Impact project manager at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "It was a textbook maneuver that placed us right on the money."
Right on the money is where Deep Impact has to be to place a 1-meter-long (39-inch) impactor spacecraft in the path of a comet about as big as the island of Manhattan that is bearing down on it at 37,100 kilometers per hour (6.3 miles per second). At the same time, from a very comet-intimate distance of 500 kilometers (310 miles), a flyby spacecraft will be monitoring the event. This all occurs in the wee hours of July 4 - at 1:52 am Eastern time (July 3, 10:52 p.m. Pacific time) -- at a distance of 133.6-million kilometers (83-million miles) from Earth.
"With this maneuver our friends working the Hubble Space Telescope are assured a ringside seat," said Deep Impact Principal Investigator Dr. Michael A'Hearn of the University of Maryland, College Park. "Their observations, along with space telescopes Chandra and Spitzer and numerous ground-based observatories, will provide us with the most scientific bang for our buck with Deep Impact."
Deep Impact is comprised of two parts, a "flyby" spacecraft and a smaller "impactor." The impactor will be released into the comet's path before a planned high-speed collision on July 4. The crater produced by the impact could range in size from the width of a large house up to the size of a football stadium, and from 2 to 14 stories deep. Ice and dust debris will be ejected from the crater, revealing the material beneath.
The Deep Impact spacecraft has four data collectors to observe the effects of the collision. A camera and infrared spectrometer, which comprise the High Resolution Instrument, are carried on the flyby spacecraft, along with a Medium Resolution Instrument. A duplicate of the Medium Resolution Instrument on the impactor will record the vehicle's final moments before it is run over by comet Tempel 1 at a speed of about 37,100 kilometers per hour (23,000 miles per hour).
The overall Deep Impact mission management for this Discovery class program is conducted by the University of Maryland in College Park, Md. Deep Impact project management is handled by JPL. The spacecraft was built for NASA by Ball Aerospace & Technologies Corporation, Boulder, Colo.
Hmmm.... sounds like it could be a cosmic "seemed like a good idea at the time" moment....
(steely)
The impact should be visible from earth. It won't be seen from Fairbanks of course, just as the geomagnetic storm today isn't visible here.
The technology is similar to what is used on the ABM interceptor.
I should have guessed. Target's moving a bit faster, but it's a tad larger too. And, I would imagine, a wee bit colder. Not much of an IR signature, but given the background...
(steely)
It's the equivalent, relative mass and momentum wise, of a bug hitting the window of a semi.
At the relative impact speed the impactor and part of the comet will be vaporized and partly ionized in a brilliant flash. If a bug did that to the windshield of my Peterbilt, a cross-country drive would be more interesting.
Did anyone read the article about the Russian astrologist who was suing NASA for this mission upsetting her 'cosmic balance'?
There was something about that a couple months ago. The timing is bad. She needs to wait until we have left the Age of Materialism.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.