In The Martian, what does Mark use to burn to help make water? What is the significance of this object? Who did it belong to? How does Mark feel about it?
In The Martian, Mark Watney uses the Hab's (Habitat) hydrazine fuel to burn and create water. The hydrazine fuel, which is typically used by the Hab's machinery, contains hydrogen and nitrogen, and when burned, it releases water vapor as a byproduct.
The significance of this object is that it allows Mark to generate water, which is a crucial resource for his survival on Mars. Water is necessary for drinking, growing crops, and sustaining life in general on a barren planet like Mars.
The Hab's hydrazine fuel belonged to the crew of the Ares 3 mission, of which Mark Watney was a member. The crew had brought it with them as part of their supplies.
Mark feels grateful and fortunate to have access to the hydrazine fuel. Although it is not meant to be used as a primary source of water, Mark realizes its value and resourcefulness in generating water for his survival.