Howard Astronomical League - Meetings

Speaker: Bob Dutilly

Title: Spacecraft Mission Development

Abstract: This is a presentation on the entire process from a concept through all of the stages that a spacecraft mission goes through to launch.  I plan on quickly discussing each stage for a successful mission.  The scientists can work on the concept stage for a number of years prior to having it approved.

Bio: Bob worked at Goddard Space Flight Center from 1982 until his retirement in 2008. He has experienced all mission stages except for the prelliminary concept stage.

Speaker, Mark Perry

Title: Ring rain and tar polluting Saturn: a new understanding of the interactions between Saturn and its rings. 

Abstract:
For forty years, calculations based on remote observations indicated that Saturn’s magnetic field carries ions and charged particles from the rings to the mid latitudes of Saturn. In Cassini’s spectacular last few months of life, direct, in situ measurements found that ten tons per second of molecules and particles smaller than two nanometers are streaming along the plane of the rings into Saturn’s atmosphere by another process: atmospheric drag. Saturn’s extended atmosphere reaches the inner edge of Saturn’s rings and extracts neutral particles less than one thousandth the thickness of a human hair by slowing them down until they fall into Saturn. Surprisingly, the flux is a hundred times larger than past predictions, and at least half of the material is hydrocarbon, which comprises less than 5% of the water-ice-dominated rings. Cassini’s data also show that the influx varies at least a factor of four and may be linked to clumps that appeared in 2015 on D68, the ringlet on the inner edge of the rings. These newly discovered particles and processes alter the evolutionary landscape of the rings and provide an exciting, rich field for future research aimed at understanding the origin and history of the rings. 

Short bio:
Mark Perry, a planetary scientist at the Johns Hopkins Applied Physics Laboratory, uses data from in situ mass spectrometry and remote observations such as RF occultations to study the internal structure of rocky planets, the magnetospheres of outer planets, the plumes of icy moons such as Enceladus, the topography of asteroids, and now the interactions between the rings of Saturn and its atmosphere. Before returning to research, Dr. Perry spent fifteen years involved with live-cycle engineering and managing many missions, from deep-space missions such as the MESSENGER mission to Mercury and the New Horizons mission to Pluto, to technology-demonstration missions, the International Space Station, and astrophysics missions such as the Far Ultraviolet Spectroscopic Explorer

Speaker: Dr. Albert Holm, Retired. Formerly a staff member for OAO-A2, the International Ultraviolet Explorer, and the Hubble Space Telescope.

Title: Out of this World Astronomy: The Orbiting Astronomical Observatory-A2 

Abstract: What could be better than a telescope on a high mountain? In 1946, Lyman Spitzer published a paper arguing for the development of a large telescope in space. The technology to do that did not exist then nor in the decades after Sputnik. The Orbiting Astronomical Observatory series provided stepping stones for developing and testing the technologies that eventually would be used for the Hubble Space Telescope, the implementation of Spitzer's dream. 2018 is the 50th anniversary of the December 7, 1968, launch of Orbiting Astronomical Observatory-A2, the first satellite to deliver astronomical data about stars, planets, and galaxies to Earth. This is the story of that mission, its operations, its discoveries, and its legacy.