|
|
Some notes on our meeting of the 8th of March and excerpts from subsequent emailings:
Keith Wetzel, Dave Dietzler, Mark Rhode, Chris Nobbe, and Bob Perry attending; Burt Sharpe and David Heck, our other core members, were unable to attend, missing a good meeting. Our members and the people on our mailing list are invited to our next meeting; bringing something to share is not a requirement but is recommended.
|
1.
|
Bob handed out twenty-five Lunar Landings Maps and bookmarks to Dave Wetzel for a second grade teacher he knows. Chris reported that she received a package of two hundred of the Lunar Landings Maps from LPI but none of the bookmarks so Bob gave her a pack of one hundred. She decided to save them to be handed out at next year's Moon Madness Night. We all congratulated her on this year's event.
|
2. |
Bob showed a hard copy of the rough draft of "Development of the Moon", a white paper in work at LPI by Michael B. Duke, Lisa R. Gaddis, G. Jeffrey Taylor, and Harrison H. Schmitt.
http://www.lpi.usra.edu/lunar_resources/developmentofmoon.pdf
He also had a copy on his thumb drive that Keith and Dave uploaded to their laptops. Dave had found it while searching the web for information about lunar mining. Bob JPGed Table 12, Potential Resources, Possible Host Materials, and Their Grades, and posted it here. He promised to do up an HTML version and post that as well.
|
3. |
Dave discussed a two part sketch. The first was of a lava flow that cooled slowly - slowly enough for the various mineral components to separate out by density. The second showed a complex impact crater in such a lava flow on the moon. He speculated that the subsequent central peak would consist of the denser materials, minerals that would be prohibitively deep otherwise. Bob recalled reading about complex craters in a report posted by the Canadian Geological Survey and promised to email the URL to everyone.
|
|
data base of known terrestrial craters
http://www.unb.ca/passc/ImpactDatabase/
and an essay about the processes in the formation a crater
http://www.unb.ca/passc/ImpactDatabase/essay.html
Another report that includes information about complex craters is "Traces of Catastrophe" (LPI Book CB-954) posted by the Lunar and Planetary Institute
http://www.lpi.usra.edu/publications/books/CB-954/CB-954.intro.html
|
|
Chapter three discusses the crater formation process and Figure 3 -- 11 -- D a complex crater (central peak) is shown here, color added.
Bob emailed Peter Kokh about this discussion and he responded
I think that most lunar geologists expect that the central peaks represent upthrust mantle material, from several miles below the surface. But that might mean just more olivine and plagioclase. Not sure, but at any rate, crater central peaks remain an unexplored province of the lunar surface, along with the ASP basin and the permashade areas near the poles.
Yes, we need to sample these sites. Some central peaks are surrounded by smooth lava flows and easier to access overland -- Tsiolkovksy on the farside, for example.
Bob then replied
. . . BTW, I Googled <Tsiolkovsky "on the far side"> and found
http://www.honeysucklecreek.net/msfn_missions/Apollo_15_mission/hl_Apollo15.html
which includes photos of the crater. Apparently, Hamish Lindsay, the author of the fascinating multi page website,
http://www.honeysucklecreek.net/msfn_missions/
was very active in supporting Apollo and other missions.
Some URLs with false color images of the moon,
useful in determining the minerals on the surface of the moon,
have been added to the
links page.
4. |
Dave also presented a quick discourse on space suits. He discussed several pages from "The Millennial Project" by Marshall T. Savage.
The conventional "balloon suit" has one real advantage - it's a proven technology - and several disadvantages. The suit is designed to enclose the astronaut in a mini-atmosphere of pure oxygen at 4.3 PSI (close to the partial pressure of oxygen at sea level) so after being helped into the suit the astronaut must gradually transition from the normal atmosphere of the shuttle or the space station to avoid the bends. This takes a significant amount of time. Additionally, if the suit integrity were compromised, the astronaut would have a real problem. Apparently, the next generation suit will be a hard suit, one with multiple complex joints, although a skinsuit is still getting some consideration.
|
5. |
Keith Wetzel discussed the March 2006 Scientific American article "Shielding Space Travelers" and a chapter from "Spheres of Influence".
The magazine article discussed the radiation hazards for which space travelers must be prepared and means to protect them. The article gives an overview of electromagnetic, electrostatic and extensive mass shielding. LEO is not bad and hurrying through the Van Allen Belt is not a great risk but working long term out on the surface of the Moon or Mars or at geosynchronous orbit is a serious health risk without significant shielding. The article concluded with a "more to explore" giving the URLs
http://aoss.engin.umich.edu/Radiation/ and http://www.radiationshielding.nasa.gov and another article by Eugene Parker, "Shielding Space Explorers from Cosmic Rays" in Space Weather, Vol. 3, Article no. S08004, August 18, 2005.
Keith will post excerpts from "Spheres of Influence" on his personal website.
|
Edited and posted by Bob Perry
Webmaster |
| |
|