Chinese astronauts arrive at Chinese space station

China’s burgeoning space program took reached a milestone Wednesday after two Chinese astronauts boarded the recently-launched space station, Tiangong-2.

Excluded from international cooperation on the International Space Station (ISS), China’s space agency has advanced through the stages of the space race rapidly, building a space program that some say could grow to rival that of the United States. Wednesday’s feat comes just 13 years after China’s first successful manned spaceflight.

"China is building its own capability and their aim is clearly to become the world leader in space exploration," former NASA astronaut Leroy Chiao told NBC News.

China’s 9.5-ton Tiangong-2 space station launched in September, just days before the country’s space agency announced that the station’s predecessor, Tiangong-1, would crash through Earth’s atmosphere in 2017.

The first Tiangong space laboratory launched in September, 2011, and was briefly visited by Chinese astronauts, or taikonauts, twice. This time, however, the two taikonauts who boarded Tiangong-2 on Wednesday are expected to stay for more than a month, conducting experiments and testing station systems.

After arriving on Tiangong-2, taikonauts Jing Haipeng and Chen Dong, “extended greetings to all the people of the nation in the space lab, and checked the status of the space complex," China’s state news agency Xinhua reported, according to Phys.org. A veteran of many space missions, Mr. Jing will turn 50 while in space.

The taikonauts are expected to help prepare for the launch of the station’s core module in 2018, as well as performing medicine and space science experiments. The manned spacecraft that ferried China’s astronauts to the space station, Shenzhou 11 (Divine Vessel in Mandarin), also carried three science experiments by Chinese middle schoolers into orbit.

China has been forced to forge forward with its space program on its own, after the United States deemed the country’s space program too military in character for cooperation.

Nevertheless, China has made vast leaps in space innovation over the 13 years since its space program first sent a man into orbit. In 2007, just four years after China’s first crewed spaceflight, the country launched a lunar orbiter.

In 2013, 10 years after its first spaceflight, China landed a lunar rover, Yutu (also known as Jade Rabbit), on the moon’s surface, where it operated until this summer.

And while Tiangong-1 will meet an ignominious end in 2017, Chinese officials expect Tiangong-2 to be fully operational by 2022, fewer than 20 years after the country’s first manned spaceflight.

Despite being barred from working with the United States and the International Space Station, China plans to open its own space station to international cooperation. While Tiangong-2 will be much smaller than the 420-ton ISS when completed, China has offered to finance other countries' missions to its space station.

China also hopes to send a probe to Mars within the next decade, with the hopes of pushing the boundaries of exploration to the Red Planet, just as the United States has done.

Although China still lags the United States and Russia in its space capabilities, its rapid advances showcase both the advantages that latecomers can gain by using technology already developed by other nations, as well as president Xi Jinping’s determination to make space exploration a priority.

"Becoming an aerospace power has always been a dream we've been striving for," President Xi Jinping said on China’s first Space Day this year, NBC News reports.