Thanks, Leland. This was another interesting one. It's the first time I've ever heard of Nancy Roman, but she appears to be a very eminent and distinguished astronomer. The people in the Gravity Probe B Program have been very good at feeding us fascinating tidbits of tangentially related information, as we await the actual results of the Gravity Probe B mission.

Mike

>Hi,
>
>Here is the Gravity Probe B Update for August 19, 2005.
>
>#---------------------------
>
>=============================================
>GRAVITY PROBE B MISSION UPDATE FOR 19 AUGUST 2005
>==============================================
>
>GP-B STATUS AT A GLANCE
>=============================
>Mission Elapsed Time: 486 days (69 weeks/ 16 months)
> IOC Phase: 129 days (4.2 months)
> Science Phase: 352 days (11.6 months)
> Final Calibration Phase: 5 days
>Current Orbit #: 7,169 as of 1:00PM PST
>Spacecraft General Health: Good
>Roll Rate: Normal at 0.7742 rpm (77.5 seconds per revolution)
>Gyro Suspension System (GSS): Drag-free off during calibration phase
>Dewar Temperature: 1.82 kelvin, holding steady
>Global Positioning System (GPS) lock: Greater than 98.0%
>Attitude & Translation Control (ATC): X-axis attitude error: 166.9 marcs rms
>Y-axis error: 254.5 marcs rms
>Command & Data Handling (CDH): B-side (backup) computer in control
>Multi-bit errors (MBE): 1 (in GSS#1 Computer on 8/17/05)
>Single-bit errors (SBE): 10 (daily avg.)
>Telescope Readout (TRE): Nominal
>SQUID Readouts (SRE): Nominal
>Gyro #1 rotor potential: 0.2 mV
>Gyro #2 rotor potential: -0.6 mV
>Gyro #3 rotor potential: -1.8 mV
>Gyro #4 rotor potential: 1.4 mV
>Gyro #1 Drag-free Status: Backup Drag-free mode (normal)
>
>
>MISSION DIRECTOR'S SUMMARY
>=======================
>As of Mission Day 486, the Gravity Probe B vehicle and payload are in good health and all subsystems are performing nominally.
>On Monday, 15 August 2005, the Gravity Probe B mission concluded the science phase of the mission and transitioned to the final calibration phase of the mission. In total, the mission collected science data for 352 days (11.6 months) during its 7,000+ orbits around the Earth with an extremely high data capture rate for that time (99.0%).
>
>The final calibration phase officially began at 6:26am (PST) on Monday when the drag free gyro (Gyro #1) was transitioned to "drag free off." After setting the gyro preloads to the IOC levels of 10V (Initialization & Orbit Checkout Phase), we maneuvered the space vehicle to point at HD216235, a star one degree away from the guide star. On Tuesday, we returned to the guide star and resumed drag-free operation. On Wednesday and Friday, we are repeating these maneuvers to the neighboring star (HD216235). The aim of these calibrations is to place tight constraints on potential systematic errors.
>The calibrations are scheduled to be completed by 31 August. With any remaining helium, further calibrations will be performed at a different spacecraft roll rate.
>
>GP-B MISSION NEWS--DR. NANCY ROMAN VISITS GP-B; REX GEVEDEN APPOINTED ASSOCIATE NASA ADMINISTRATOR
>=========================================================
>Two notable events related to GP-B occurred this past week. First, this past Tuesday and Wednesday, we were honored with a visit from Dr. Nancy Roman, one of the nation's leading scientists in the space program.
>Roman received her PhD in astronomy from the University of Chicago in 1949. She began her career doing astronomy research in stellar distances and motions at the University of Chicago's Yerkes Observatory and also teaching graduate courses there. In 1959, Roman joined NASA, and from 1960-1979, she served as Chief of the Astronomy and Relativity Programs in the NASA Office of Space Science. In her position at NASA, Roman was very influential in creating astronomical research satellites such as the Cosmic Background Explorer (COBE) and the Hubble Space Telescope (HST).
>
>She also oversaw the development of a number of ground and space research programs, including Gravity Probe B. In fact, Roman helped organize a NASA-sponsored two-day seminar, held at Stanford in July 1961, in which over 30 distinguished physicists, engineers, and aerospace experts from all over the U.S. gathered to discuss the possibilities of testing Einstein's theories of relativity in space. Some of the ideas discussed at that seminar--most notably the concept of a drag-free satellite--are currently being used in the GP-B mission. After retiring from NASA in 1979, Dr. Roman continued working as a contractor at the Goddard Space Flight Center. Throughout her career, Dr. Roman has been a spokesperson and advocate of women in the sciences.
>
>This past week was Dr. Roman's first trip to Stanford since 1979, but she has been following the progress of Gravity Probe B through our weekly updates. During her visit, she sat in on several mission status briefings, she met with scientists and engineers on the GP-B team, she attended a student presentation session and had lunch with the students and staff, and she toured the GP-B development labs and Mission Operations Center. We've included some photos from Dr. Roman's GP-B visit, plus a black and white NASA photo taken early in her career, in this week's highlights on our Web site. You can read more about Dr. Nancy Roman at http://solarsystem.nasa.gov/people/profile.cfm?Code=RomanN
>
>Also in the news this past week, NASA Administrator Michael Griffin named Rex Geveden as the agency's associate administrator. In this capacity, Geveden has oversight for all the agency's technical missions' areas and field center operations. He will be responsible for programmatic integration between NASA's mission directorates and field centers. In November 2004, Geveden moved from NASA's Marshall Space Flight Center (MSFC) in Huntsville, AL to NASA Headquarters in Washington DC to become NASA Chief Engineer. He has been serving as acting associate administrator since June 2005.
>
>Prior to moving to NASA Headquarters, Geveden held various leadership positions at MSFC. He served as deputy director of the Marshall Center from July 2003-November 2004. Prior to that, he was deputy director of the MSFC Science Directorate, leading research and development projects in space science, materials science, biotechnology, earth science and space optics. Geveden was project manager for several successful efforts, including the Optical Transient Detector and Lightning Imaging Sensor satellites, which produced data for the world's first global map of lightning.
>However, we here at GP-B have a special connection with Rex Geveden. From 1995-2003, Geveden was the NASA MSFC Program Manager overseeing GP-B's final development and testing, and readying the spacecraft for launch. Geveden has long been a staunch supporter of GP-B, and we wish him every success in his new position at NASA. You can read the NASA press release announcing Geveden's appointment last week at: http://www.nasa.gov/home/hqnews/2005/aug/HQ_05227_geveden.html
>
>
>===================
>PREVIOUS GP-B UPDATES
>===================
>If you wish to read any of our previous updates, our GP-B Web site includes a chronological archive of all the updates/highlights (with photos and drawings) that we have posted over the past 8 years: http://einstein.stanford.edu/highlights/hlindexmain.html
>
>=============================
>OTHER LINKS THAT MAY INTEREST YOU
>=============================
>
> * Our GP-B Web site, http://einstein.stanford.edu contains lots of information about the Gravity Probe B experiment, general relativity, and the amazing technologies that were developed to carry out this experiment.
>
>
> * Visual tour of the GP-B spacecraft and payload from our GP-B Web site: http://einstein.stanford.edu/content/vehicle_tour/index.html
>
>
> * PDF file containing a 1/20 scale, paper model of the GP-B spacecraft that you can download print out, and assemble: http://einstein.stanford.edu/content/paper_model.
>
>
> * NASA's Marshall Space Flight Center also has a series of Web pages devoted to GP-B: (http://www.gravityprobeb.com)
>
>
> * Photo, taken through a telescope by Swiss physics teacher and amateur astronomer Stefano Sposetti, of GP-B spacecraft in orbit, passing near IM Pegasi: http://aida.astronomie.info/sposetti.
>
>
>
> * The Harvard-Smithsonian Center for Astrophysics (Cambridge) and York University (Toronto), with contributions from the Observatoire de Paris, have been studying the motions of the guide star, IM Pegasi for over a decade. To find out more, visit: http://www.yorku.ca/bartel/guidestar/
>
>
> * In addition, you'll find information in the Guide Star FAQ on our Web site: http://einstein.stanford.edu/content/faqs/faqs.html#guidestar and on pages 18-20 of the Gravity Probe B Launch Companion: http://einstein.stanford.edu/highlights/GP-B_Launch_Companion.pdf.
>
>
> * Track the GP-B satellite on the Web using NASA's Java-based J-Pass satellite tracking application at: http://science.nasa.gov/realtime/JPass/ Also, you can track the GP-B satellite on Personal Digital Assistants (PDAs) using either the Palm OS or Pocket PC operating systems with software from Big Fat Tail Productions: http://www.bigfattail.com.
>
>
> * The Einstein Exhibition at the Skirball Cultural Center in Los Angeles has closed.However, you can visit the American Museum of Natural History's virtual Einstein exhibit on the Web at: http://www.skirball.org/exhibit/amnh_frame.html.
>
>
>
>==========================
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>==========================
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>
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>
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>
>--
>
>**********************************
>NASA - Stanford - Lockheed Martin
> Gravity Probe B Program
>"Testing Einstein's Universe"
> http://einstein.stanford.edu
>
>Bob Kahn
>Public Affairs Coordinator
>
>Phone: 650-723-2540
>Fax: 650-723-3494
>Email: kahn@relgyro.stanford.edu
>**********************************
>
>#------------------------------
>
>Regards,
>
>LelandJ