1. 20c - 1 NASA’s Goddard Space Flight Center Propulsion Chuck Zakrwski NASA/GSFC Code 597 August 16-17, 2005

2. 20c - 2 NASA’s Goddard Space Flight Center Lunar Reconnaissance Orbiter (LRO) Propulsion System Document Tree Level 2 431-RQMT-000004LRO Mission Requirements Document 431-PLAN-000131Lunar Reconnaissance Orbiter Spacecraft Performance Assurance Implementation Plan 431-OPS-000042Lunar Reconnaissance Orbiter Concept and Operations Document 431-ICD-000008Lunar Reconnaissance Orbiter Electrical Systems Interface Control Document 431-SPEC-000091Lunar Reconnaissance Orbiter General Thermal Subsystem Specification 431-RQMT-000012Lunar Reconnaissance Orbiter Mechanical Environments and Verification Requirements Level 3 431-SOW-00017Lunar Reconnaissance Orbiter Propulsion Subsystem Statement of Work and Specification 431-LIST-000135Lunar Reconnaissance Orbiter Propulsion Subsystem Deliverable Items List and Schedule 431-RQMT-000045Lunar Reconnaissance Orbiter Radiation Requirements 431-RQMT-000092Lunar Reconnaissance Orbiter Thermal Math Model Requirements Level 4 431-SPEC-000136Lunar Reconnaissance Orbiter Propellant Tank Specification 431-ICD-(TBD)Lunar Reconnaissance Orbiter Propulsion Subsystem Mechanical Interface Control Drawing

3. 20c - 3 NASA’s Goddard Space Flight Center Level 2 Req.Level 3: RequirementsConcept/Compliance ParagraphRequirement MRD 1.1.46 MRD 3.3.46 4.2.1[The propulsion subsystem shall be capable providing the listed] delta-V requirements for the given functional requirements: Fuel budget calculated using the given delta-V requirements. MRD 1.1.264.2.1.1The propulsion subsystem shall be capable of de-spinning the SC after separation from the third stage of the launch vehicle from a maximum of 5 RPM about the x-axis. Conceptual design compliant by means of placement and canting of thrusters and tank PMD design specification. MRD 1.2.22 MRD 3.3.26 4.2.1.1The propulsion subsystem will also be capable of nulling maximum tip-off rates of up to 2 degrees per second (deg./sec) in any axis after separation from the launch vehicle. Conceptual design compliant by means of placement and canting of thrusters and tank PMD design specification. MRD 1.3.664.2.2The propulsion subsystem shall be capable of performing all delta-V maneuvers with a thrust impulse accuracy of better than 5%. Candidate thruster capable of 5% or better impulse accuracy. Lunar Reconnaissance Orbiter (LRO) Propulsion System Level 2 Flow Down Key Requirements

4. 20c - 4 NASA’s Goddard Space Flight Center Level 2 Req.Level 3: RequirementsConcept/Compliance ParagraphRequirement MRD 3.3.544.2.4.1The Propulsion subsystem shall provide a minimum total continuous thrust level of at least 140 Newtons (N) for all lunar insertion burns in the +X SC direction. The propulsion subsystem shall be capable for providing this thrust for at least ninety (90) minutes. Conceptual design compliant by use of two 90+N thrusters for insertion burn. MRD 3.3.744.2.4.3The propulsion subsystem shall have the capability of providing a minimum impulse bit of [less than or equal to] 0.3 N*sec in the +X direction, 0.06 N*sec in + and – Y [and Z] directions over the entire mission lifetime. Conceptual design compliant by use of 22 N ACS thrusters with acceptable minimum impulse bits. MRD 1.2.22 MRD 3.3.26 4.2.7.1 {4.2.10.1} [The total wet mass of the propulsion subsystem shall not exceed 713.3 kg] The maximum amount of propellant shall not exceed 711.1 kg { and the pressurant gas shall not exceed 2.2 kg}. This propellant allocation shall include all propellant required for all delta-V and attitude control maneuvers as well as subsystem residual propellants and uncertainties in propellant loading. The maximum propellant shall encompass worst-case (- 3 sigma) subsystem performance. Conceptual design compliant using -3 sigma values for specific impulse and delta-V requirements. TBD4.2.8The propulsion subsystem shall be designed to use High-Purity grade hydrazine per “MIL-PRF-26536E with Amendment 1” as the propellant. Compliant by specification Lunar Reconnaissance Orbiter (LRO) Propulsion System Level 2 Flow Down Key Requirements

5. 20c - 5 NASA’s Goddard Space Flight Center Level 2 Req.Level 3: RequirementsConcept/Compliance ParagraphRequirement GSFC-STD- 1000 1.2 4.8.9The propulsion subsystem shall be an all welded subsystem. Use of threaded mechanical assemblies shall be limited to the fill and drain vale (e.g., poppet, AN cap, external cap) and the pyro valve initiators. Compliant by specification MRD 1.2.26431-SPEC- 000136 (TBD) The propellant tank shall be designed such that fluid motion inside the tank does not produce a spacecraft/launch vehicle nutation time constant outside the launch vehicle specification. Compliance will be demonstrated by means of “drop tower” tests of scaled s/c and tanks Lunar Reconnaissance Orbiter (LRO) Propulsion System Level 2 Flow Down Key Requirements

6. 20c - 6 NASA’s Goddard Space Flight Center P P Pressurant Tank (Helium) P R R High Pressure Panel Fill/Drain Valve Panel Low Pressure Panel Dual Thruster Module #1 Dual Thruster Module #2 Dual Thruster Module #3 Dual Thruster Module #4 R R Pressure Transducer Fill and Drain Valve Pyrotechnic Valve (Normally Closed) Filter Latch Valve Regulator Propellant Management Device 5 lbf Thruster 20 lbf Thruster P Cylindrical Propellant Tank (PMD) Lunar Reconnaissance Orbiter (LRO) Propulsion System Block Diagram

7. 20c - 7 NASA’s Goddard Space Flight Center Lunar Reconnaissance Orbiter (LRO) Propulsion System Preliminary Verification Approach Components –All components, with possible exception propellant tank, are expected to have been previously qualified –Nutation time constant constraints may require tank re-qualification –Acceptance testing required of all components (mechanical, thermal, and electrical) –Thruster acceptance testing to include ‘hot-fire” tests which encompass worst case thermal environments Propulsion Module –All welded system with NDE of all welds –Functional tests at pre- environmental, post environmental and launch site include: Proof, System Leak, Valve Leak, Electrical Functional, Gas Flow Impedance –Environmental tests options include: Acoustics, Sine Sweep, Sine Vibration, Thermal Vacuum/Balance –System designed to be “wet” with test fluid for environmental tests –Enable plugs in subsystem to prevent inadvertent operation of all valves and catalyst bed heaters during I&T

8. 20c - 8 NASA’s Goddard Space Flight Center Lunar Reconnaissance Orbiter (LRO) Propulsion Summary LRO Propulsion driving requirements are defined Propulsion functions and delta-V requirements has been established Preliminary architecture has been identified which will satisfy driving requirements GSFC acquisition of propellant tank allows interface requirements between subsystems to be defined at appropriate levels Interfaces between the propulsion system and the following subsystems have been defined at Level 3 and are being developed at Level 4: Mechanical Thermal ACS Electrical Power Propulsion system ready to proceed to contractor selection/award and PDR