WASHINGTON (NEXSTAR) – Four astronauts are ready to fly to the moon, but NASA said the equipment to get them there is not, so they’ll have to wait.

Congress, who approves the money for these missions, wants to know more about what caused the delay and its potential impacts.

“We have adjusted the Artemis II schedule based on crew safety,” Catherine Koerner, a NASA associate administrator, told a House committee Wednesday.

Koerner said some of the main issues stem from the spacecraft’s heat shield and life support system.

“We want to fully understand that before we put Reid, Victor, Christina and Jeremy on Artemis II,” she said.

The crew planned to fly to the moon later this year, but NASA pushed the flight to September 2025. Artemis III, the first human moon landing in more than 50 years, is also now delayed to September 2026, which former NASA Administrator Dr. Michael Griffin said is still too soon.

“I don’t think the Artemis III, the landing mission, is at all realistically scheduled,” Griffin said.

U.S. Rep. Zoe Lofgren, (D-Calif.), noted NASA relies heavily on private companies for the rocket, moonwalking suits and other equipment.

“If one of these elements is delayed, what happens to the whole program?,” Lofgren asked.

Koerner said all of NASA’s industry partners have signed on to the new launch date, but lawmakers worry the U.S. may be losing the space race, which they said is a matter of national security.

“Whoever controls space will control the destiny of this earth,” said U.S. Rep. Bill Posey, (R-Fla).

Posey stressed China is working to put astronauts on the moon by 2030.

“We are not on a path to recognize that,” Griffin said.

NASA has repeatedly delayed these efforts over the past decade, which makes the Artemis program more expensive. Government audits estimate it will cost more than $90 billion through 2025.

Lawmakers haven’t passed a comprehensive NASA funding bill in nearly a decade but plan to consider one this spring.