"The development of earth independence (EI) extends human presence beyond low Earth orbit (LEO) and cislunar space and onto Mars. Missions during this stage of exploration range from 2-3 years with safe return of the crew to Earth taking months.
Johnson Space Center (JSC) provides agency leadership for the development and analysis of human spaceflight architectures, mission plans, and surface system definitions. JSC is a leader in technology developments for Habitats, Space Suits, In-Situ Resource Utilization, and Entry, Decent, and Landing Systems and provides unique mission integration and test environments. JSC is the NASA's lead center for Astromaterials (
https://www.nasa.gov/centers/johnson/astromaterials) and a leader in the science of planetary destinations."
References:
Nasa.gov. (2015, May 5). Human Exploration and Operations: Deep Space. Retrieved from
https://www.nasa.gov/johnson/exploration/deep-spaceAf.mil. (1993, Nov. 1). Air & Space Manual 36-2234, Instruction Systems Development (ISD). Retrieved from
http://www.au.af.mil/au/awc/awcgate/edref/afman36-2234.pdfAf.mil. (2014, Jun. 11). Air Force Instruction 10-207, Air Force Space Command Supplement, Operations Command Posts. Retrieved from
http://static.e-publishing.af.mil/production/1/afspc/publication/afi10-207_afspcsup/afi10-207_afspcsup.pdfPerdue.edu. (n.d.). Instructional Systems Design (ISD): Using the ADDIE Model. Retrieved from
https://www.lib.purdue.edu/sites/default/files/directory/butler38/ADDIE.pdf