After the Viking landers and the Mars Pathfinder's rover landed on Mars, the onboard instruments were used to determine the properties of the Martian soil at the landing sites. The studies of the Martian soil properties led to the development of JSC Mars-1 Martian regolith simulant at NASA's Johnson Space Center in 1998. It contained palagonitic tephra with a particle size fraction of less than 1 millimeter. The palagonitic tephra, which is glassy volcanic ash altered at low temperature, was mined from a quarry at the Pu'u Nene cinder cone. The studies of the cone, which is located between Mauna Loa and Mauna Kea in Hawaii, indicate that the tephra is a close spectral analog to the bright regions of Mars.