Firefly Blue Ghost Mission 1: SCALPSS 1.1 Short Focal Length Camera Descent Imaging

Stereoscopic imagery obtained during the Firefly Blue Ghost Mission 1 landing by NASA’s Stereo Cameras for Lunar Plume-Surface Studies (SCALPSS) instrument is reported in this paper. The SCALPSS 1.1 six-camera system operated during transit to the moon, and captured imagery during and after descent to the lunar surface. This paper reports imagery from a pair of cameras equipped with 5.4 mm focal length lenses which imaged the area beneath a pair of reaction control system (RCS) thrusters. Starting at an altitude of 30 m, clear images of the lunar surface were obtained. Around 18 m altitude, clear streaks appear in the images indicating entrainment of lunar dust associated with plume-surface interaction. Closer to landing, additional regolith is lofted, obscuring the images while also visualizing various fluid mechanical phenomena such as a shock structure and streaking behavior. Below 2 m altitude, a pair of circular plumes associated with the RCS thrusters are clearly seen with streaks emanating outward radially. The image intensity alternates between bright and dark, corresponding to the RCS thrusters pulsing. Finally, at landing, the imagery shows the lander settling to a stable resting position. Qualitative discussion of these phenomena is contained herein while quantitative analysis will be reported elsewhere.