Operating LADEE: Mission architecture, challenges, anomalies, and successes

Abstract

NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE) mission was both a lunar science and a technology demonstration mission. The goals identified for LADEE were to determine the composition of the lunar atmosphere and investigate the processes that control its distribution and dynamics, and to determine whether dust is present in the lunar exosphere and reveal the processes that contribute to its sources and variability. LADEE was also developed to serve as a platform for the Lunar Laser Communications Demonstration (LLCD), which had the goal of demonstrating the viability of high-speed optical communication to and from the Moon. LADEE met all of these objectives by operating a robotic spacecraft in a low-altitude, near circular, near equatorial lunar orbit where remote sensing and in-situ instruments measured the Moon's atmosphere and dust environment, and the LLCD demonstrated optical communications at lunar distances. The spacecraft was launched in September of 2013, and spent approximately one month in a transfer orbit before being inserted into lunar orbit in October. It orbited the moon for 188 days, logging time over five lunar synodic months, i.e., "lunations", before being decommissioned via surface impact in April of 2014. LADEE exceeded its baseline mission duration by greater than 40% in terms of time in the science orbit, and greater than 200% in terms of science data return. This paper summarizes the LADEE mission architecture and describes the operational phase of the LADEE mission in detail. The combination of an aggressive science campaign, the demonstration of a new optical communications payload, and the first-use of a new low-cost spacecraft bus resulted in an operational phase filled with challenges, both planned and unplanned. We explain our approach to orbit determination, maneuver planning, attitude planning, activity planning and command sequencing, which yielded exceedingly positive results in the face of a demanding operational timeline consisting of hundreds of interleaved instrument and spacecraft activities. In addition, we discuss the team's identification of, and response to, several in-flight anomalies including a shutdown of the spacecraft's reaction wheels immediately following launch and an on-going unexpected behavior of the on-board star-tracker and attitude state estimation system. Finally, we reflect on the operations experience overall, the successes that LADEE enjoyed, and some suggestions for future lunar missions.

Development, Demonstration and Validation of the Deep Space Orbit Determination Software Using Lunar Prospector Tracking Data

“…The GEODYN was used for precise orbit determination in the case of the Chang'e-1, the first Chinese lunar exploration mission (Jianguo et al 2010), and the Lunar Reconnaissance Orbiter (LRO) which provided a high-resolution survey of the Moon (Mazarico et al 2012). For the Lunar Atmosphere and Dust Environment Explorer (LADEE) mission, that aimed at determining the composition of the lunar atmosphere, dust environment and viability of optical laser communication technologies (D'Ortenzio et al 2015), the orbit determination tool kit (ODTK), a commercial software of the AGI, was used for the operation. Although commercial softwares are verified through various missions and are easy to use, they are hard…”

Multi-purpose spacecraft simulator for LADEE

“…The three areas in which the LADEE simulator was used in Mission Operations were: 1) Development and testing of spacecraft command scripts using PIL and HIL simulators before and during the mission 2) Operator training during mission simulations and readi ness testing using the HIL simulator before the start of the mission 3) Ve rification of all tactical command sequence files up loaded using WSIM and PIL simulators For an in depth description of the LADEE Mission Opera tions see [12].…”

A Deep Space Orbit Determination Software: Overview and Event Prediction Capability

“…MONTE is based on the JPL's legacy software packages DPTRAJ and ODP, and has served all of JPL's deep space missions, such as Cassini and Gravity Recovery And Interior Laboratory (GRAIL), since 2012 (JPL 2017). The orbit determination tool kit (OTDK) is a commercial software package developed by Analytical Graphics Inc., and has been successfully applied to the Lunar Atmosphere and Dust Environment Explorer (LADEE) mission along with the company's other software package, Systems Tool Kit (STK) (D'Ortenzio et al 2015).…”