The status of AXAF was presented by Harvey Tananbaum. Since last year AXAF-S has been cancelled. The XRS detector possibly can be flown on Astro-E. The team at MSFC, however, which had been assembled for AXAF-S has been disbanded and this is a real loss. AXAF-I launch will be on the Shuttle with an upper stage supplied by Boeing. AXAF funding is $220-230 Million per year and is on a three-year plateau; one year has been completed and we are anticipating the second. The program is subject to many reviews. One has just finished and two more are scheduled for June.
Steve Kahn asked how much money would be available for general observers. Greg Davidson stated that NASA Headquarters is anticipating that $30-50K will be available for each AXAF investigation.
There are technical challenges and there has been appreciable progress. The two outer mirrors, which were made larger than their final length to make polishing easier, changed shape when excess material was cut off the ends. The shape change (affecting about 10% of the glass near the ends) was caused by stresses in the glass and was not a surprise to the AXAF team, who had allowed for this possibility by setting aside project reserves and schedule slack to deal with it. The potential impact on encircled energy, without further correction, might be as much as 1 - 2 arcseconds. Procedures have been developed for handling this, and results have been good. Ends have been cut off three of the six remaining blanks, with the remaining three due to be cut in the next few months. Then the mirrors will be polished to their final specifications and put together in an assembly. Work at Eastman Kodak Corporation is already underway to test the procedures for assembling the glass pieces into a mirror assembly. The science instruments are in good shape. The High-Energy Transmission Gratings are being fabricated in-house at MIT. CCD's similar to those for AXAF-I are being used in ASCA. The HRC team is investigating the use of low-background (no radioactive potassium) glass.
See also Report from the Project Scientist and AXAF Mirror Fabrication.
----------------