John works for Hernandez Engineering in the Earth Science and Solar System Exploration Division. Currently, he spends most of his time in a soil chemistry and mineralogy laboratory developing a mineral-based plant growth substrate that is being tested in the Advanced Life Support Program. John is also studying the soils on the Moon and Mars for their possible use in growing plants at future lunar or martian outposts.

John was born and raised on the west side of Houston, Texas. As a boy, he visited his uncle at the Johnson Space Center and watched the development and testing of the Apollo spacecraft that would take men to the Moon.

In 1986, John received a Bachelor's Degree in Aerospace Engineering from the University of Texas at Austin, and started work at the Johnson Space Center, as a systems engineer in the area of advanced mission planning for the exploration of the Moon and Mars. In 1994, John received a Master's Degree in Physical Sciences from the University of Houston-Clear Lake with an emphasis in planetary geology, and began working more closely with scientists in the development of scientific instruments and science operations that could be used on the Moon or Mars.

John is very active in many education/outreach programs at JSC and the surrounding area.