Signs Of LIfe Detector (SOLID) is an analytical instrument under development to detect extraterrestrial life in the form of organic biosignatures obtained from a core drill  during planetary exploration.
The instrument is based on fluorescent immunoassays and it is being developed by the Spanish Astrobiology Center (CAB) in collaboration with the NASA Astrobiology Institute. SOLID is currently undergoing testing for use in astrobiology space missions that search for common biomolecules that may indicate the presence of extraterrestrial life, past or present. The system was validated in field tests and engineers are looking into ways to refine the method and miniaturize the instrument further.