MSRScienceBest of Beyond Apollo VIIBy David S F PortreeScienceBest of Beyond Apollo IIBy David S F PortreeScienceFootsteps to Mars (1993)By David S F PortreeScienceDirect Return from Mars Rover to Earth (1989)By David S F PortreeScienceThe Science of Sample Return: the MRSR SWG (1989)By David S F PortreeScienceMars Rover/Sample Return Pre-Phase A (1988)By David S F PortreeScienceInternational Mars Rover Sample Return (1987)By David S F PortreeScienceMars Sample Return: A Different Approach (1988)By David S F PortreeScienceMerits of a Locality Sample (2002)By David S F PortreeScienceMars Sample Return Site Selection & Sample Acquisition Study (1980)By David S F PortreeScienceMartian Weight Problem: Mars Sample Return Version 0.7 (1998)By David S F PortreeScienceLinking Space Station & Mars: the IMUSE Strategy (1985)By David S F PortreeScienceRobot Rendezvous in Mars Orbit (1999)By David S F PortreeScienceMars Polar Ice Sample Return (1976-1978)By David S F PortreeScienceMars Sample Return: Vive le retour des-chantillons martiens! (1999)By David S F PortreeScienceModel Rockets on Mars Redux (1998)By David S F PortreeScienceModel Rockets on Mars (1998)By David S F PortreeScienceMars Sample Recovery & Quarantine (1985)By David S F PortreeScienceJPL/JSC Mars Sample Return Study II (1986)By David S F PortreeScienceJPL/JSC Mars Sample Return Study I (1984)By David S F Portree
