In the 1960s, President Kennedy successfully challenged us to land an American on the moon and return him safely to the Earth within a decade. Today, President Trump and Vice President Mike Pence have issued us an even greater challenge: Do the same in five years, but in a manner that supports “long-term exploration and utilization,” or in NASA Administrator Jim Bridenstine’s words, “this time to stay.”

It is quite a challenge. It can be done. And it can be done for much less than we spent in the 60s.

What’s the cause of the paradigm shift in cost?  It’s the new availability of reusable rockets costing about five times less, like the whole world witnessed again this month with the successful return of the 3 Falcon Heavy rockets.  This technology will allow for payloads not before even considered due to their very high costs. It has revolutionized our ability to go to the moon, Mars and beyond.

Here is the larger plan: The rockets would dock in space, in low earth orbit, multiple times. To do this there is already a good option that is currently available. Four flights of SpaceX Falcon Heavy, costing about $500-600 million, can take 25 tons to the lunar surface and have enough propellant left over for the journey back to the capsule. Of the four upper stages that would land on the surface, tanks of all but one can be used for future habitats, while one would be used for sending the capsule back to Earth.

These tanks left on the surface, after the fuel inside them is expended, are large enough, at 3.5 meters in diameter and eight or six meters in length, for astronauts to live in, walk around, and sleep in comfortably. If inflatable habitats from companies like Bigelow aerospace are placed inside, it would make for a comfortable environment. They could be covered in lunar regolith or placed inside lava-tubes to reduce the radiation hazard.

Another alternative could be Blue Origin’s New Glenn, when it is available. Their technology would make it possible to take even larger payloads such as the Orion capsule with the European Service Module together. New Glenn’s tanks would be palatial in size at 6.5 meters in diameter and 12 meters in length for the empty hydrogen tanks — a place to go to for their weekly meetings! Multi-use and multi-purpose ideas are necessary to make the Trump/Pence challenge a reality.

If done several times, we actually can have people working on science, learning to live in that environment of one-sixth the gravity of Earth and no air, and also learning to help others live there later by prospecting for water-ice. Even this, which would be done over several years, would cost much closer to a few tens of billions of dollars, perhaps, rather than the hundred billion number quoted elsewhere.

The other main driver which makes the Trump/Pence idea possible at low cost is water. We have 600 million tons of water-ice on the moon. That is what will fuel our journeys deeper into space. This water-ice will not only support life on the moon, but it can of course also be separated into the propellant mix of liquid hydrogen and liquid oxygen using solar electricity. This amount of water-ice is almost a million times more than what we would need to send one rocket from there to other destinations such as Mars but far less expensive.

Then, when the shallower gravity on the lunar surface compared to Earth is taken into account, the water becomes more precious than if diamonds were found there — although we may later find those too.  When considering the cost of trying to bring this water from Earth, one can easily see its importance. Other countries are and will go after this resource.  We cannot afford to stand idly by even for a few years.

Yes, President Trump and Vice President Pence are right. It can be done in five years and for a few billion dollars, not a hundred billion as the fear mongers suggest. The sky will not fall in terms of cost, but the sun will rise on a better future for the United States and humanity.

Ajay Kothari is an aerospace engineer and president of Astrox Corporation. Todd Rokita is a former vice chair of the U.S. House Committee on the Budget. The authors have no relationship with or loyalty to SpaceX, Blue Origin or Bigelow Aerospace — only with and to this country.