The following charts that have been attached are for the maximum lander mass for each particular case. The volumes of fuel and oxidizer can not be calculated until the mass ratios are obtained from Rockwell. We are playing phone tag at the moment.
The attitude control system (ACS) is used to maintain the second stage in flight attitude with roll, pitch and yaw control plus propellant setting. During vehicle coast phase after first burn the second stage engine, the ACS performs the necessary course correction maneuvers of pitch, yaw and roll to keep the vehicle in its correct attitude for engine restart and subsequent third stage or payload separation.
The nitrogen cold gas jet Redundant Attitude Control System provides 3-axis control during coast periods and roll control during power flight; hydrolic gimballing of the main engine provides pitch and yaw control under the command of DIGS at the forward end. Three helium spheres provide tank pressurization. Four aft isogrid panels provide equipment attatch points and tank fill ports; the gas spheres are filled through the mini-skirt on path.
In near zero gravity, just prior to engine restart, the ACS propellant setting valves are energized to provide thrust, causing a forward acceleration to settle the propellant to the bottom of their respective tanks. This ensures propellant availability to the thrust chamber for engine restart. THe ACS operates by controlled release of pressurized gaseous nitrogen through various nozzles which are aligned with specific axes of the vehicle. The gaseous nitrogen is stored in a high pressure spherical titanium alloy tank. For the 3-stage configuration, the third stage is spin stabilizied, thus not requiring an ACS system.
We are attaching a spreadsheet that we used to calculate the burn times associated with the maximum angular velocities, and the smallest possible angular velocities. This data was used to select the TRW Space and Technology Group's MRE-4 monopropellant hydrazine thrusters. The dry mass of this engine is 0.41 kg. The total mass of propellant seems to be approximately 1 kg.
The RCS team will continue with our schedule that was given as an earlier progress report.
The same goes for the launch vehicle selection.