"If we find out there's water on the moon, and we want to do more extensive operations on the moon to go explore that, we have the ability with Deep Space Gateway to support an extensive Moon surface programme", he said adding a dash of hope that it may one day find the resources to send humans to Mars.
Recent comments made by NASA's head of human spaceflight appear to show that NASA simply can't afford to land astronauts on Mars anytime soon.
Gerstenmaier comments come almost a month after Lt. Gen. Larry James, the deputy director of NASA's Jet Propulsion Laboratory, said the space agency had its sights set on Mars for the near future. Now the launch, descent and landing on Mars is a huge problem for us.
NASA has no money for a mission to the Red planet.
Likely to landing humans on Mars will need to attract commercial space companies such as SpaceX.
Earth's last survivors are going to be water bears
In this context there is a real case for looking for life on Mars and in other areas of the solar system in general. Objects such as dwarf planet Pluto are big enough to cause the oceans of the Earth to boil if they hit.
Moreover, Elon Musks's SpaceX has also set a deadline of 2018 for an unmanned Mars mission and 2025 for a named mission.
Gerstenmaier told the American Institute for Aeronautics and Astronautics that NASA might be interested in another Moon mission instead.
"Sending humans to orbit Mars is our primary mission now", James said during a speech entitled "Exploring Our World, the Solar System and the Universe" in Chennai, India. "If we want to stay focused more toward Mars we can keep that", concluded Gerstenmaier.
Mr Gerstenmaier's admission comes just days after Vice President Mike Pence said that the USA will "usher in a new era" of American space leadership, but budget cuts for Nasa from the Trump Administration seem to have taken its toll. The Space Launch System, supposed to fly only once a year, would cost more than $1 billion.
Mars One, which aims to establish a permanent settlement on planet Mars, puts the cost of sending four people there at $6 billion.