Viewing page 15 of 63

This transcription has been completed. Contact us with corrections.

The SRB tailoff and resulting g-level after SRB SEP were more dramatic than expected. Even though previous crews had debriefed it, several of the crewmembers commented that the transition from three-g to less than one-g immediately after SRB SEP was more dramatic than anticipated.

Although the second-stage ride was much smoother than the first stage, the CDR noted a "rumble" which was not present during his previous flight on Columbia. The "rumble" was also noticed by the other crewmembers and was constant throughout the second stage.

The "new" APU/HYD and MPS gauges in Discovery were not usable. The gauges utilize a gray-on-gray discrete LCD-type indicator (+-5 percent) as opposed to the more accurate white-on-black moving tape indicate used in the other Orbiters and all simulators. The gray-on-gray color combination made it almost impossible to be certain at a glance whether the APU fuel quantities or the HYD quantities were at 100 percent or at 0 percent. The MPS Pc guages were equally difficult to read clear, and the +-5 percent accuracy made it extremely hard to verify the throttle settings during the throttle-up from 100 percent to 104 percent after tower clear and during the two-stage throttle-down at max q. (The better accuracy of the "old" tape-type Pc meters in the SMS had permitted the crew to use the two-stage throttle-down settings to anticipate a "low first-stage performance" call. This procedure is impossible with the inaccuracies inherent in the new MPS gauges.) Several abort procedures require the PLT to determine throttle settings quickly and accurately; this technique is no longer possible the Pc gauges in Discovery. Taking over manual throttle control, which requires the PLT first to "match" the current Pc setting with the SBTC, would also be more difficult. As the first crew of Discovery, with the first operational exposure to the "new" APU/HYD and MPS Pc gauges, we do not want to leave anyone with the mistaken impression that the gauges can be used if subsequent crews have sufficient training. The gauges are not usable, are unsatisfactory, and need to be modified or replaced as soon as possible. or the resulting reduction in crew capability must be recognized by ground controllers and accepted by management.

The PLT performed a reach and visibility evaluation throughout second stage. Until the two-g level was reached at about 6:30 minutes into flight, all switches could be seen and reached easily, including all the OMS/RCS switches on overhead panels 07 and 08. After approximately 6:30 minutes when the g-level exceeded two-g's, it became dramatically more difficult to see and reach the OMS/RCS TK ISO switches on panels 07 and 08. It would have been difficult to reposition any switches on the overhead panels confidentely expect the RCS MANF ISO switches and the OMS/RCS crossfeed swithces. The switches on panel R4 also could not be reached at greater than two-g's with any degree of assurance; however, all switches on panels R1 and R2 could be confidently repositioned throughout the ascent.

The PLT was able to raise his seat and observe the external tank during ET SEP. The separation was extremely quite. The SMS ET SEP sequence is much too hard and loud and should be modified to be like the real Orbiter.

After the OMS burns, it was noted that some of the tiles in the starboard overhead window (W9) were chipped.

With a satellite deployment on the first day of the flight, the crew had a busy post-insertion timeline. A nominal post-insertion SMS period close to launch was