NASA is finding it difficult to send a human to Mars on its current budget, says William H. Gerstenmaier, the human spaceflight chief at the American Space Agency. According to Gerstenmaier, it is simply not possible for NASA to announce a date by which it would be able to send a manned mission to Mars as the agency doesn’t have enough money to accomplish the mission.

Gerstenmaier’s remarks came on Wednesday while he was addressing a propulsion meeting of the American Institute for Aeronautics and Astronautics.

NASA’s Mars mission

Over the past few years, the American space agency has been talking about its plans to send a manned mission to the Red Planet.

On March 21, President Donald Trump issued a mandate for the agency to get people to Mars by the 2030s, and within a week, NASA came up with a detailed plan for landing a human on the Red Planet. Despite all those announcements, it appears there are many glitches for NASA along the road to Mars.

NASA’s Orion spacecraft was scheduled to make its first flight into space in 2018, but the funding challenges have forced the agency to push back the mission to 2019. The agency was also thinking about sending humans into space aboard Orion as part of the EM-1 mission, but that idea has also been dropped following a feasibility study.

Experts now think NASA will eventually have to rely on private companies such as United Launch Alliance, Blue Origin, and SpaceX to accomplish its deep space exploration plans.

All these companies are currently trying to develop a reusable rocket booster to limit the cost of space travel. SpaceX wants to accomplish an unmanned Mars Mission by 2018 and a manned mission by 2025. Earlier this month, SpaceX founder Elon Musk indicated that his SpaceX might come up with an update about its Mars mission in September during the International Astronautical Congress in Australia.

Challenges for a Mars mission

According to Gerstenmaier, entry, descent, and landing on Mars are the biggest challenges for NASA. The atmosphere on Mars is thin and shallow, meaning a spacecraft carrying humans, supplies, and other equipment will face significant difficulties while entering the Mars atmosphere. Similarly, the launch requirements for a return mission demand that the rocket used needs to be much smaller than an Earth-to-orbit rocket.

Whether NASA will continue or drop its Mars mission will depend on the budget allocated by the Trump administration for NASA. In case the agency drops its Mars mission, a good option—as indicated by Gerstenmaier—for the agency would be a Moon exploration mission supporting “an extensive moon surface program."