Monday, September 07, 2009

Vernier jets

Wow, something I actually know about the space shuttle. Discovery's vernier jets failed, so they have to use the primary reaction control system (RCS) jets to move around while on orbit. The bigger RCS jets are at 90 degrees to each other (i.e., directly in line with yaw, pitch, roll axes), and the vernier jets much less powerful, so aren't as jerky for maneuvering. From Spaceflight Now:
The shuttle's forward reaction control system, or RCS, includes 14 primary engines and two vernier jets. Two aft RCS pods feature 12 primary thrusters and two verniers each. The primary engines generate 870 pounds of thrust while the verniers produce just 24 pounds of push.
The software we were analyzing was the DAP jet-select and deadbanding (more than you ever wanted to know here). We spent a lot of time with this "Phase-plane" diagram.

Changing subjects, a Wyland painting was stolen from a Waikiki store on Lewers Street. Which is more surprising: that it was snatched from a gallery during business hours, or that there's a Wyland painting worth $700k? :) Anyway, support your local tiki.