Editor’s note: NASA’s proposed Deep Space Gateway has been in the news recently due to a joint statement of support for the project from US and Russian officials. However, as former space shuttle pilot and International Space Station commander Terry Virts writes in an op-ed below, there is little agreement in US space policy circles about the need for the gateway.

Consider the following proposal for a human spaceflight program. First, a multinational consortium comes together to build a space station, with each nation responsible for specific pieces of the station or capabilities, such as module or robotic arm. Second, the station relies on existing rockets and vehicles to launch cargo and crew, effectively providing these programs a raison d’etre for many years to come. Third, the consortium develops an “assembly sequence” of missions to put the station’s modules together in orbit, one by one. Then, once the space station is built, astronauts use it to perform experiments and prepare for eventual missions deeper into the Solar System.

Does this program sound familiar? You may think this is the International Space Station—but it is not. Rather, this is NASA’s recent proposal for something called “Deep Space Gateway.” But there are several key differences between this new program and the ISS. Most notably, the gateway would be built in orbit around the Moon. Also, it will not use the Space Shuttle for assembly but instead rely on NASA’s Space Launch System rocket and Orion spacecraft, vehicles that should be operational by the mid-2020s.

The people at NASA who have developed the gateway concept are some of the brightest people that I know, and they have tried as best they can to shepherd our human spaceflight program through the past decade, even as it lacked a concrete goal or mission. Nevertheless, America deserves a thoughtful and critical examination of this plan. For if we choose to pursue it, America and its international partners will be committing to this pathway for the next few decades of human spaceflight.

What’s the goal?

So let’s consider some key questions about the Deep Space Gateway plan. Any project should have a clear goal. It really doesn’t matter if you are building a fast food restaurant chain, negotiating peace in the Middle East, or designing a human spaceflight program—having a focused goal is essential.

In the case of this gateway, there is no concrete human spaceflight goal. Instead, there is simply a fuzzy promise of having an “ecosystem” of capability in orbit around the Moon that will eventually enable humans to go to Mars. It is the “if you build it, they will come” strategy, which may have worked well enough for Kevin Costner but is highly suspect when it comes to space.

In the 1960s, NASA made it to the Moon by flying increasingly complex missions, each designed to build on the previous one, developing and demonstrating the technologies eventually needed for a Moon landing. It was Mercury, then Gemini, and finally Apollo that got us to the Moon, not just Apollo.

The International Space Station has served as a type of project “Mercury" for extended human missions by proving that long-duration spaceflight is possible. As the follow-on to ISS, the Deep Space Gateway program would fill the role of “Gemini,” a stepping-stone to develop and prove technologies necessary for our next destinations—be it the Moon, Mars, or beyond.

It’s critical to ask whether building another space station, one that costs 10 times as much as the ISS to service and supply and comes with a significant decrease in crew mission duration, would really be a stepping stone. This is not a trivial question, as space stations are something we can do much more cheaply and safely in low Earth orbit. To justify the cost, there must be some technology required for deep space missions that we will gain from a space station in lunar orbit.

To answer this question, we must have a well-defined, long-term goal. Moon colonies? Boots on Mars? Something else? If we don’t have the goal, we are putting the proverbial chicken before the egg by developing “Gemini” before we know what “Apollo” will look like. Regardless of a future destination, as someone who lived on the ISS for 200 days, I cannot envision a new technology that would be developed or validated by building another modular space station. Without a specific goal, we’re unlikely to ever identify one.

Separate crew and cargo

Beyond questions of strategy, there is an elephant in the room that has been ignored for almost a decade. NASA’s plans call for launching astronauts in the Orion capsule on top of the massive SLS heavy lift rocket. After the STS-107 Columbia accident in 2003, NASA underwent some serious soul-searching. Investigators wrote the Columbia Accident Investigation Board report, which revealed some serious cultural flaws at the agency. An axiom that came out of that difficult time was the need to “separate crew from cargo.” The Space Shuttle had launched crew and cargo together and had two accidents out of 135 missions. We decided that future astronauts should launch in smaller and safer capsules, while cargo should be launched on more massive (and perhaps less safe) rockets.

For myriad reasons, NASA is choosing to abandon this safety dictum and launch its astronauts on the heaviest rocket ever, SLS, which will simultaneously be carrying payloads. I will use the adjective “unwise” to describe this new plan. It is dangerous and violates the basic post-Columbia accident principle. It is also expensive, as each SLS launch will cost on the order of $2 billion. And finally, the massive Orion capsule eats up about 25 tons of capacity that could otherwise be occupied with payloads such as habitation modules or landers.

The plan to launch Orion on SLS forces NASA to human-rate the largest rocket ever built, carrying with it expenses that are not required on rockets that only launch cargo. It would seem to make more sense to multiply the cost of a smaller, cheaper rocket in order to human-rate it rather than the largest and most expensive rocket ever built. For example, NASA is already going through the exercise of human-rating both the Atlas V and Falcon 9 rockets for commercial crew launches. Both of these rockets will have dozens of cargo launches behind them before their first crew missions. By contrast, NASA plans to fly crew on just the second flight of the SLS rocket.

With a new president and National Space Council, what the United States needs now is strong bipartisan support to lead a robust international partnership in a bold and significant new program of human space exploration. The Deep Space Gateway architecture, while developed by some of the smartest and most dedicated engineers at NASA, will not accomplish this goal. Instead, it will ultimately be judged as a jobs program aimed at providing work for existing programs. The gateway may be a good “answer” but not to a question that needs to be answered.

A great nation like America deserves a great space program, and the international community is waiting for exactly that kind of strong and visionary leadership. If America does not provide this leadership, other nations will.