Crew 18, in its entirety, arrived at MDRS from Salt Lake City on Saturday evening, April 26, 2003 and brought the Habitat back to life over the next 2.5 days from a two week hiatus due to the cancellation of Crew 17. This crew had well-rounded and ambitious research goals. Six out of the seven crewmembers brought personal research topics to pursue during the manned Mars mission simulation.

Our simulation guidelines came mainly from two NASA publications: The Mars Project: Avoiding Decompression Sickness on a Distant Planet by Conkin and The Mars Surface Reference Mission: A Description of Human and Robotic Surface Activities, edited by Stephen Hoffman. We entered the full simulation mode on Tuesday, April 29, 2003 at noon and ended on Saturday, May 10, 2003 at noon.

The most important simulation rules were:

1. Only go outside in a spacesuit and include a 30 minute pre-breathe in the airlock.
2. Perform one hour of exercise per day when not on EVA.
3. When on EVA, you must be within walking distance of the Habitat with the remaining suit consumables.
4. Take one day off every six days.
5. Take a navy shower every other day at the maximum to conserve water.

Other aspects of the simulation worth noting included: no direct contact with the outside world, a delayed interaction with mission support based on the Mars to Earth distance, required reports to be communicated daily to mission support.