{\rtf1\ansi\ansicpg1252\deff0\deflang1033{\fonttbl{\f0\fswiss Arial;}{\f1\fswiss\fcharset0 Arial;}} \viewkind4\uc1\pard\f0\fs20 Payload information\par MASS 3321.8 kg is our allocation. 3144.8 is our present mass. Worst case uncertainty for knowing the vehicle mass is 7.07 kg.\par \par SIZE 2441 liter dewar, \par \tab 2.64 meter diameter\par \tab 6.43 meter length\par \par Optical Telescope\par \tab Aperture 14 cm\par \tab Focal Length 3.81 meters\par \tab mirror diameter 14.2 centimeters\par \par Dewar contains 4 gyros, two at different orientations (90 degrees opposite the other two) for ruling out any orientation effects. Liquid helium and 1.8K is correct. Our drift rate is less than one hundred billionth of a degree per hour (not sure if that corresponds to your figure - check the math). \par \par GPS receiver - we have two (one on at a time, the other as a back up). Both were custom made by Trimble for us. \par \par Laser retroreflectors - we do use those (I think we have one, but I am not sure - I'll check with OD) and I know we are processing laser ranging data. \par ------------------------------------------\par \par Orbit Information\par \tab 640 km x 640 km x 90 degrees to the equator. Circular, polar orbit\par \tab Precision for inclination is exceptionally precise and important to mission, but altitude, while it must be well know, does not need to be as strictly adhered to. I believe that we have to know the altitude to 25 meters, but if we were say, 655x 655 it might not be a problem. However, if we stray from 90 degrees by more than a tiny little bit, that's bad. I'll check with the OD people (orbit determination) to get specifics. \par \par GP-B Launch info\par Launch vehicle - Boeing Delta II rocket. I can check the model number with our VAFB guy.\par Launch profile I have listed as follows (and this will change slightly as we get nearer to launch)\par \tab Stage 2 Burn 1 L + 278 seconds\par \tab\tab Fairing Separation L + 281 seconds\par \tab Stage 2 End Burn 1 L + 676 seconds\par \tab Stage 2 Burn 2 L + 3698 seconds\par \tab Stage 2 End Burn 2 L+3714 seconds\par \par \tab Space Vehicle Separation L+4500 seconds\par \par I am told by a separate source that circularization of orbit occurs @ ~ 61 minutes after launch, so I am assuming that is during stage 2 burn 2.\par \par Solar panel deployment would be after SV separation, I believe, but I don't know the time. I can check into it. \par \par Cooldown can mean several things - do you mean dewar cooldown or SV cooldown or what? Again, I'll have to check into it because I couldn't find that magic binder )\par -----------------------------------------------\par GP-B Results\par All correct, however other effects measured could include geodesy. For a long time we carried a co-experiment on our books of helping to map the geoid with our drag free and highly precise orbit information. However, no one every volunteered to help with the very slight extra cost of the co-experiment, so it was officially dropped from our list of experiments (we only have one experiment and one science instrument on board). I believe some of the data could still be used to some minor geodesy work. We do take into account several effects in our measurement, including special relativity, and especially the motion of our guide star, IM Pegasi (HR 8703). That star has been observed by VLBI coordinated by the folks at the Smithsonian Astrophysical Observatory for several years, and this is an important component in our work. \par \par Cheers,\par Jennifer\par \par \par At 0742 PM 7/17/2003 -0400, Jonathan McDowell wrote\par Jennifer -\par Actually I think the launch sequence details up to Delta separation will\par be made public by Boeing on its web site near to launch, and of course the\par detailed final orbit will be tracked and made public by US Space Command.\par So if there are materials along those lines you don't have a go to release,\par you can refer people to those sources. The satellite-specific stuff\par - mass, size etc - is what only you and Lockheed can answer. Thanks very\par much for the crucial info that the sunshade cover is hinged rather than\par separable, and I appreciate your responsiveness. \par Cheers, Jonathan\par PS If any of the GP-B team ever make it to Boston, they should feel free\par to contact me for a tour of the Chandra mission control center.\par \f1\par }