Dozens of NASA scientists and engineers gathered at Kilauea Military Camp last week for a research program to simulate potential future geologic and biologic surveys on Mars.

The project, known as the Biologic Analog Science Associated with Lava Terrains, or BASALT, ended Saturday, the Hawaii Tribune-Herald reported.

Each day during the project, two “astronauts” hiked across the lava rock on Kilauea, collecting and storing rock samples, while in communication with about 40 scientists and engineers at a mission control center elsewhere on Kilauea.

All communications between the astronauts and mission control are delayed between four and 22 minutes, the time it takes for light to travel between Earth and Mars, a distance that varies depending on where they are in their orbits.

“All human spaceflight so far has been managed in real time,” said Darlene Lim, principal investigator for BASALT. “But how do we manage a mission where there can be a 40-minute time delay for a single response?”

This is the project’s third deployment and the second on Hawaii island. Last year, the project conducted similar simulations on Mauna Ulu.