NASA sees Gateway as a base for staging missions beyond the moon. What’s the next stop? Mars. The space agency plans to build a special craft for the trip. The Deep Space Transport will carry astronauts from Gateway to the Red Planet and back. This will reduce the enormous cost of shuttling supplies for a Mars mission all the way from Earth. The Mars transport could even expand its size by attaching one of Gateway’s habitat modules. Which statement is a central idea supported by the details in the excerpt?

The central idea supported by the details in the excerpt is the statement that "This will reduce the enormous cost of shuttling supplies for a Mars mission all the way from Earth."

Explanation:

a) The central idea of an excerpt is the element that unifies the story.  It ties other the elements together.  It is the dominant impression or the universal, generic truth found in the story.  It is also known as the main idea, which, in most cases, is not clearly stated in a write-up.

b) According to www.nasa.gov, "NASA's Phase 1 Gateway includes a Power and Propulsion Element, Habitation and Logistics Outpost and logistic supply. The Gateway will be an outpost orbiting the Moon that provides vital support for a sustainable, long-term human return to the lunar surface, as well as a staging point for deep space exploration."