Science is grant-driven. As much as we need and appreciate our grants, they do not cover all of our expenses. There are only a few grants available for our specialized work, and sometimes we even compete with our own scientists for these funds.
Grants are also unpredictable. Even if we get them, we might not find out until late in the game. This makes it hard to plan, budget and buy the necessary items we need for our complex expeditions.
We need survival and rescue gear, medical supplies, specialized science equipment, lab analysis of samples, helicopters, volcanic gas monitors, satellite phones, breathing apparatus, and expedition-quality food and tents. This all adds up.