Propulsion - Lamar 2/23/96 Progress Report

For the Spring Semester the Lamar Propulsion Subsystem has changed its focus. Last semester the propulsion team focused its attention on the conceptual design of MPS and RCS and launcher selection. The initial goal of this semester was to refine the work done by the team from last semester. After consultation with our professor, the focus of this semester's work has changed to a detailed design of the MPS. The team's new goals to be accomplished this semester are as follows:

- Determine the amount of propellant required of the MPS   		2-22-96*
- Size tanks for fuel and oxidizer									2-29-96
- Select hardware for plumbing
	- Tubing (length, diameter, material)								3-21-96
	- Valves  (type, function)											3-28-96
	- Regulators														3-28-96
	- Insulation (placements, thickness, layers)						4-15-96
	- Material Compatibility 											3-7-96
- Pressurant (tanks, amount, size, plumbing)							3-21-96
- Power Requirements (thrusters, valves, regulators, heaters)				3-7-96
- Thermal Requirements (temperatures of propellants and pressurant)	2-29-96
*Tentative dates of completion.
Other unknown items will be dealt with as they arise. If all of these items are accomplished, a detailed design of the MPS will be achieved.

After consulting with SIG on 2-20-96, the suggested design of the MPS has been changed. The new configuration consists of six Marquardt R40B rocket engines with no auxiliary thrusters. This engine has the following specifications: thrust = 4000 N (nominal), mass = 11.34 kg., Specific Impulse = 303 sec. maximum run time is continuous, power consumption = 2.5 amps @ 28 V dc. These engines will perform the necessary DV's throughout the mission. Most likely there will be no jettisoning of these engines during the final descent to the lunar surface.

Using this new configuration, the propellant requirements were calculated with the lander mass ranging from 200 - 500 kg. or until constraints of the launcher were exceeded. The following table contains the lander mass with the required propellant mass for the mission:

SIX Engines THREE Engines
Lander Mass (kg) Propellant Mass (kg) Propellant Mass (kg)
200506.98156442.63562
225554.26777489.92183
250601.55398537.20804
275648.84019584.49427
300696.1264631.78046
325743.41261679.0667
350790.69882726.35288
375837.98503773.63909
400885.27124820.9253
425932.55745868.21151
450N/A915.49772