(CNN) China's Shenzhou 11 "heavenly vessel" launched Monday (7:30 p.m. Sunday ET) from Jiuquan Satellite Launch Center in the Gobi Desert. The launch was shown on state broadcaster CCTV.

This is China's longest-ever crewed space mission. On board are two astronauts -- Jing Haipeng and Chen Dong. They will dock with the Tiangong-2 space lab, which was launched last month.

Jing and Chen will remain in space for a total of 33 days, with 30 of those spent conducting experiments related to medicine, physics and biology in the space lab.

Since October 2003, China has completed five manned space flight missions -- the last one took place in 2013 and lasted 15 days.

China's Shenzhou 11 spaceship onboard a Long March-2F carrier rocket takes off from the Jiuquan Satellite Launch Center in northwest China's Gansu province on Monday Oct. 17, 2016.

Ultimate goal

The Tiangong-2, and its predecessor Tiangong-1, are prototypes for China's ultimate goal -- a permanent 20-ton space station, which is expected to be sent into orbit in 2022.

China aims to send its space station into orbit two years before the International Space Station (ISS) retires in 2024, according to state news agency Xinhua.

Chinese astronauts Jing Haipeng, right, and Chen Dong, left, wave farewell to the crowd before getting on Shenzhou 11 on Oct. 17, 2016.

"Tiangong is a precursor testbed of capabilities, building toward the large space station has always been the culminating goal of the Shenzhou program," said Joan Johnson-Freese, a professor at the Naval War College specializing in space programs and space security.

The Tiangong-1, China's first space lab, is expected to fall into the Earth's atmosphere by late 2017. Some experts have speculated that China has lost control of the vessel.

However, Wu Ping, deputy director of the manned space engineering office, played down any chance of damage.

"Based on our calculation and analysis, most parts of the space lab will burn up during falling," she said in a press conference last mont h, adding that it was unlikely to affect aviation activities or cause damage to the ground.

#Shenzhou11 astronauts Jing Haipeng and Chen Dong meet press. Jing (L) named mission commander #SpaceChina pic.twitter.com/Rft3yerCbz — CCTVNEWS (@cctvnews) October 16, 2016

Permanent space presence?

Once the ISS goes out of service, China potentially will be the only country with a permanent space presence.

European astronauts are said to already be learning Chinese in anticipation but unless there is a change in US policy, American astronauts are unlikely to be involved.

Since 2011, the US Congress has barred NASA from contact with China's space program because of national security concerns.

"Chinese politicians certainly have wanted to work with the United States in space, to show they are an accepted part of the international family of space-faring nations, but with their own space station forthcoming and international partners other than the US willing and lining up to work with them, that imperative decreases," Johnson-Freese said.

China was late to the space race -- it didn't send its first satellite into space until 1970 -- just after the United States put the first man on the moon.

But in the decades since, China has pumped enormous amounts of money and resources into research and training. Future plans include sending a robotic probe to Mars and a potential manned mission to the moon.

"If the US does not change its policies very soon and begin to work with China in space, it will lose whatever leverage it might have in shaping Chinese space plans for the future, " Johnson-Freese said.