Uncertainty Requirement Analysis for the Orbit, Attitude, and Burn Performance of the 1st Lunar Orbit Insertion Maneuver

Abstract

In this study, the uncertainty requirements for orbit, attitude, and burn performance were estimated and analyzed for the execution of the 1st lunar orbit insertion (LOI) maneuver of the Korea Pathfinder Lunar Orbiter (KPLO) mission. During the early design phase of the system, associate analysis is an essential design factor as the 1st LOI maneuver is the largest burn that utilizes the onboard propulsion system; the success of the lunar capture is directly affected by the performance achieved. For the analysis, the spacecraft is assumed to have already approached the periselene with a hyperbolic arrival trajectory around the moon. In addition, diverse arrival conditions and mission constraints were considered, such as varying periselene approach velocity, altitude, and orbital period of the capture orbit after execution of the 1st LOI maneuver. The current analysis assumed an impulsive LOI maneuver, and two-body equations of motion were adapted to simplify the problem for a preliminary analysis. Monte Carlo simulations were performed for the statistical analysis to analyze diverse uncertainties that might arise at the moment when the maneuver is executed. As a result, three major requirements were analyzed and estimated for the early design phase. First, the minimum requirements were estimated for the burn performance to be captured around the moon. Second, the requirements for orbit, attitude, and maneuver burn performances were simultaneously estimated and analyzed to maintain the 1st elliptical orbit achieved around the moon within the specified orbital period. Finally, the dispersion requirements on the B-plane aiming at target points to meet the target insertion goal were analyzed and can be utilized as reference target guidelines for a mid-course correction (MCC) maneuver during the transfer. More detailed system requirements for the KPLO mission, particularly for the spacecraft bus itself and for the flight dynamics subsystem at the ground control center, are expected to be prepared and established based on the current results, including a contingency trajectory design plan.

Flight Dynamics and Navigation for Planetary Missions in Korea: Past Efforts, Recent Status, and Future Preparations

“…Apart from the phasing loop transfer phase, numerous uncertainties relating to LOI burns were also considered. Uncertainty requirement analyses for the orbit, attitude, and burn performance of the 1st LOI maneuver (Song et al 2016a) were conducted. The effect of burn delays with the inclusion of position and velocity errors (Bae et al 2016b(Bae et al , 2017b were also analyzed.…”

Burn Delay Analysis of the Lunar Orbit Insertion for Korea Pathfinder Lunar Orbiter

“…Previous studies have conducted dispersion analyses of the KPLO considering uncertainties in the trans-lunar injection (TLI) and LOI maneuvers. (Bae et al 2016a, b;Song et al 2016;Bae et al 2017a, b).…”

Observational Arc-Length Effect on Orbit Determination for Korea Pathfinder Lunar Orbiter in the Earth-Moon Transfer Phase Using a Sequential Estimation

“…To ensure successful flight dynamics operations, KARI designed a dual-simulation engine, consisting of a commercial off-the-shelf (COTS) simulation engine and a KARI simulation engine (Song et al 2018). Numerous studies (Song et al 2014;Song et al 2016;Bae et al 2017;Song et al 2017) have discussed development strategies, requirements, burn performances, and contingency designs for the development and implementation of the KPLO FDS. For the OD, the COTS simulation engine employs a sequential estimation based on an extended Kalman filter (EKF) and a backward smoother.…”