The astronaut will either be military pilot Hazza al-Mansoori or engineer Sultan al-Neyadi, two men selected from over 4,000 applicants, according to the Associated Press. Both have been training at the Star City space center near Moscow to learn the proper survival skills for space, including withstanding a zero-gravity environment.

“Since I’m a pilot, I was able to withstand a gravitational force of 9-G,” al-Mansoori said, the AP reports. “Now I must train in this sort of gravitational force, 0-G, the lack of gravity.”

Both astronaut trainees will eventually head to space, although it’s unclear who will be the first. Whoever that is will spend eight days on the ISS before returning to Earth to be replaced with the second UAE astronaut.

In training, both have had to learn to speak Russian alongside learning more technical skills. Al-Neyadi told the AP this was probably the most challenging part.

“It’s the only language which we will use to communicate with the crew onboard the vessel,” he said. “It was also the language they used while training at the center in Russia.”

The UAE’s space program sent its first locally-made satellite last October. The Earth observation satellite, KhalifaSat, launched from Japan. The UAE also aims to launch a Mars probe next year so that it will arrive in 2021, the 50th anniversary of the founding of the UAE.

More ambitiously, the program hopes to colonize the Red Planet with a city of 600,000 by 2117, says the AP.