Photo: Screenshot of Weibo

The e-commerce store for the China Aerospace Science and Technology Corporation (CASC) launched space mail service on Monday that allows customers to send letters to China's Tiangong space station. The service saw a huge influx of customers almost as soon as it started and within half a day all the store's stationary was sold out.

A customer service representative for the online store told the Global Times on Monday afternoon that its stock of stationary had sold out and that a new wave of sales will begin on July 6. For the Monday sales, the store cooperated with popular livestreamer Liu Tao, who offered 10,000 letters through his channel.

One "space letter set" costs 19 yuan ($2.94) and includes special stationery, an envelope with postage and two postcards themed after the Chinese space program.

Those who successfully bought a set can mail their letter to an address provided by the seller. The letters will be scanned onto a chip, which will be sent to a post office on the station, where they may have a chance to be displayed and read out loud to the world by Chinese astronauts.

Some netizens said they regretted that they hadn't heard about the service earlier as by the time they got to the site, all the sets had sold out. 

"I've set an alarm to inform me to scramble for the stationary set on July 6. It's very meaningful and romantic to send my words to space," one Beijing student surnamed Fang who just graduated from junior high school told the Global Times on Monday.

Fang said she has thought about what she wants to say to the astronauts. 

"I would like to ask them how they feel in space and whether there are aliens. If my letter is selected by the astronauts, I'll be so excited."

As a bridge between the public and the Chinese aerospace industry, CASC decided to implement the service at the suggestion of netizens. According to the company, this is an exploration to popularize space science in the hopes of shining a spotlight on the manned space industry and inspiring pride in China's space program, the manager of the online store told news website ithome.com.

China's Space Post Office was established in November 2011 with Yang Liwei, China's first man in space, serving as the director of the post office.

The post office is the fourth of its kind and has sent three postcards and stamps to space.

Since the launch of the Shenzhou-12 manned spacecraft, Chinese netizens curious about life in the space have been trying to learn more about life on the Tiangong space station.

Netizens have taken special interest in the fact that the electronic devices brought to China's Tiangong space station and Shenzhou-12 capsule were all produced by Chinese companies. The topic "daily life of Chinese astronauts" had 310 million views on Sina Weibo as of Monday night.

Another popular hashtag on Sina Weibo is about the meals on the space station. Netizens were surprised that astronauts are able to enjoy a popular Chinese dish, Kung Pao chicken, for lunch.