Search citation statements
Paper Sections
Citation Types
Year Published
Publication Types
Relationship
Authors
Journals
The Lunar Reconnaissance Orbiter (LRO) is a robotic exploration observatory launched on June 18, 2009. The LRO spacecraft contains a monopropellant propulsion system with twelve thrusters, two propellant tanks, a composite overwrapped pressurant tank, and fluid control hardware to regulate the propellant supply to the thrusters. This paper provides a detailed discussion of the testing process that verified the functionality of the system. Sections in this paper walk through the various component tests performed at the propulsion system level, including pressure transducer calibration, valve leakage tests, pressure regulator performance tests, and thruster gas flow impedance tests. Test descriptions provide test rationale, method and equipment, and approximate duration. This paper also includes descriptions of special propulsion tests, including heater verification testing, propulsion module vibration testing, and propulsion testing performed during the observatory-level thermal vacuum testing. This paper concludes with an explanation of the major lessons learned during functional testing, including intricacies associated with a system that includes diaphragm tanks and pressure regulator testing difficulties associated with a large downstream volume. NomenclatureACS = attitude control system AN = Army-Navy Ar = argon ATK = Alliant Techsystems COPV = composite overwrapped pressure vessel EMI = electromagnetic interference FP = flow panel GHe = gaseous helium GN2 = gaseous nitrogen GSE = ground support equipment GSFC = Goddard Space Flight Center K = thousand LRO = Lunar Reconnaissance Orbiter MEOP = maximum expected operating pressure NASA = National Aeronautics and Space Administration NSI = NASA standard initiator PGSE = pressure ground support equipment psi = pounds per square inch (gauge) RV = relief valve S/C = spacecraft SCCH = standard cubic centimeters per hour SCCS = standard cubic centimeters per second 2 Flight Component Designators AT = attitude control system thruster GFDP = gas fill and drain valve -pyrovalve GFDR = gas fill and drain valve -regulator GFDT = gas fill and drain valve -tank HGF = high-pressure gas filter HLF = hydrazine low-pressure filter -top tank HPD = high-pressure transducer HPLV = high-pressure latch valve HPR = high-pressure regulator LBLF = hydrazine low-pressure filter -bottom tank LFDB = liquid fill and drain valve -bottom tank LFDT = liquid fill and drain valve -top tank LPD = low-pressure transducer MLV = manifold latch valve NT = insertion thruster PV = pyrovalve TLV = tank latch valve
The Lunar Reconnaissance Orbiter (LRO) is a robotic exploration observatory launched on June 18, 2009. The LRO spacecraft contains a monopropellant propulsion system with twelve thrusters, two propellant tanks, a composite overwrapped pressurant tank, and fluid control hardware to regulate the propellant supply to the thrusters. This paper provides a detailed discussion of the testing process that verified the functionality of the system. Sections in this paper walk through the various component tests performed at the propulsion system level, including pressure transducer calibration, valve leakage tests, pressure regulator performance tests, and thruster gas flow impedance tests. Test descriptions provide test rationale, method and equipment, and approximate duration. This paper also includes descriptions of special propulsion tests, including heater verification testing, propulsion module vibration testing, and propulsion testing performed during the observatory-level thermal vacuum testing. This paper concludes with an explanation of the major lessons learned during functional testing, including intricacies associated with a system that includes diaphragm tanks and pressure regulator testing difficulties associated with a large downstream volume. NomenclatureACS = attitude control system AN = Army-Navy Ar = argon ATK = Alliant Techsystems COPV = composite overwrapped pressure vessel EMI = electromagnetic interference FP = flow panel GHe = gaseous helium GN2 = gaseous nitrogen GSE = ground support equipment GSFC = Goddard Space Flight Center K = thousand LRO = Lunar Reconnaissance Orbiter MEOP = maximum expected operating pressure NASA = National Aeronautics and Space Administration NSI = NASA standard initiator PGSE = pressure ground support equipment psi = pounds per square inch (gauge) RV = relief valve S/C = spacecraft SCCH = standard cubic centimeters per hour SCCS = standard cubic centimeters per second 2 Flight Component Designators AT = attitude control system thruster GFDP = gas fill and drain valve -pyrovalve GFDR = gas fill and drain valve -regulator GFDT = gas fill and drain valve -tank HGF = high-pressure gas filter HLF = hydrazine low-pressure filter -top tank HPD = high-pressure transducer HPLV = high-pressure latch valve HPR = high-pressure regulator LBLF = hydrazine low-pressure filter -bottom tank LFDB = liquid fill and drain valve -bottom tank LFDT = liquid fill and drain valve -top tank LPD = low-pressure transducer MLV = manifold latch valve NT = insertion thruster PV = pyrovalve TLV = tank latch valve
Due to the non-spherical perturbation of the Moon, the lifetime of ultra low-altitude Lunar spacecraft may be quite short. In this paper, we analyze the lifetime of about 50 km-altitude Lunar spacecraft with different initial orbit. The lifetime in low inclination orbits is much shorter than the ones in the near polar orbits. To extend the lifetime and keep the spacecraft in an appropriate range, an orbit maintenance strategy based on low-thrust propulsion system is proposed. The influence of the orbit initial conditions (e.g., semi-major axis, inclination, right ascension of the ascending node) on lifetime extension are discussed and the effect of the low-thrust magnitude in orbit maintenance is analyzed. According to the numerical simulation results, the lifetime of about 50 km-altitude 100 kg Lunar spacecraft with 10 kg fuel and 20 mN thruster can be extended from 7.958 days to over a 109.1725 days, which demonstrates the effectiveness of the strategy. Furthermore, a global perspective for ultra low-altitude Lunar spacecraft lifetime extension problem is provided in this paper, which can be applied to Moon mission designs extensively.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.