Philosophical Society of Washington

Minutes of the 2086th Meeting

Speaker: H. John Wood, Hubble Space Telescope, NASA Goddard Space Flight Center
Topic: “Latest Results From the Mars Pathfinder and Mars Global Surveyor and an Update from the Hubble Space Telescope”

President Agger called the 2086th meeting to order at 8:15 p.m. on February 20, 1998. The Recording Secretary read the minutes of the 2085th meeting and they were approved.

The speaker for the 2086th meeting was H. John Wood, astronomer and optics engineer for the Hubble Space Telescope Project, NASA Goddard Optics Branch. The title of his talk was “Latest Results from the Mars Pathfinder and Mars Global Surveyor and an Update from the Hubble Space Telescope.”

Mr. Wood gave an illustrated talk about the latest scientific results from the Hubble Space Telescope: a machine weighing in at about 24,000 pounds. The Hubble Space Telescope was originally deployed in 1990 and then redeployed in 1997 after the installation of a new instrument module with upgraded hardware by the Space Shuttle Discovery. The changeout instrument package module looked like an 800-pound icebox, or refrigerator — depending on your age and cost $150M. A photograph of the assembled Hubble Space Telescope taken by the Discovery astronauts showed the telescope about the size of a school bus floating serenely in space at 18,000 miles per hour. Among other things, the Hubble Space Telescope monitors dust storms on Mars in support of the Mars Pathfinder and Mars Global Surveyor Missions. Last July 4, 1997 the Mars Pathfinder arrived on the Red Planet in a giant air bag and landed with 20 bounces covering about a mile before finally coming to rest — surprisingly right side up. Pathfinder then deployed a small four-wheeled rover called Sojourner to explore the Martian landscape. Mr. Wood showed pictures of Sojourner rolling across the Martian landscape not unlike a child's toy car motoring about barren earth terrain. He also showed us true color photos from the surface of Mars showing that Mars has a pink daytime sky, compared to our blue one. Further, the photos showed hundreds of different sized silt covered rocks leaning to one side as they were laid down by a water flow long past. Special glasses were provided to the audience to view some of the photos in 3-D. Although not as spectacular as our 3-D photos, the images of Mars can be viewed on the World Wide Web. During his talk, Mr. Wood demonstrated a model of the Martian rover Sojourner on the floor of the John Wesley Powell Auditorium.

Mr. Wood also presented surface profiles taken by the Mars Global Surveyor laser altimeter that is currently orbiting Mars to assess the distribution of minerals, monitor global weather and map surface topography. An interesting example of the Martian topography is the Elysium Chasm which is three times deeper than the Grand Canyon and has its walls sloped 48°. Mr. Wood provided beautiful photos taken by the Hubble Space Telescope showing the auroras on Jupiter and Saturn. He also showed amazing pictures of parts of the Eagle Nebula, which is in our Milky Way but still 7,000 light years away. The photos showed towering pillars of dust and gas where new stars are forming.

The speaker then closed his presentation with a demonstration of the Doppler effect using an electronic buzzer circling at the end of a three-foot tether.

He then kindly responded to questions from the floor. President Agger thereupon thanked Mr. Wood for the society, announced the next meeting and made the usual parking announcement. She then adjourned the 2086th meeting at 9:52 p.m.


Respectfully submitted,
Bill Spargo
Recording Secretary

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