We present a description of and results from our ongoing development of miniature time-of-flight mass spectrometers (TOF-MS) for future landed planetary missions. A new, flexible TOF-MS instrument has been developed to permit the analysis of elemental, isotopic, and molecular composition in solid samples. The new instrument incorporates normal-incidence ultraviolet pulsed laser desorption, a gridless ion source, and a novel curved-field reflectron to maximize sensitivity and resolution over wide abundance and mass ranges. Results with unprepared sample materials are compared with previous work based on infrared laser ablation. Flight instruments based on these technologies can potentially be as small as a soda can without sacrificing their ability to detect low levels of atomic and organic species at grain scales. (C) 2002 Elsevier Science Ltd. All rights reserved.