  Remote sample recovery is a rapidly evolving application of Small Unmanned
Aircraft Systems (sUAS) for planetary sciences and space exploration.
Development of cyber-physical systems (CPS) for autonomous deployment and
recovery of sensor probes for sample caching is already in progress with NASA's
MARS 2020 mission. To challenge student teams to develop autonomy for sample
recovery settings, the 2020 NSF CPS Challenge was positioned around the launch
of the MARS 2020 rover and sUAS duo. This paper discusses perception and
trajectory planning for sample recovery by sUAS in a simulation environment.
Out of a total of five teams that participated, the results of the top two
teams have been discussed. The OpenUAV cloud simulation framework deployed on
the Cyber-Physical Systems Virtual Organization (CPS-VO) allowed the teams to
work remotely over a month during the COVID-19 pandemic to develop and simulate
autonomous exploration algorithms. Remote simulation enabled teams across the
globe to collaborate in experiments. The two teams approached the task of probe
search, probe recovery, and landing on a moving target differently. This paper
is a summary of teams' insights and lessons learned, as they chose from a wide
range of perception sensors and algorithms.
