Monday marked 20 years of ongoing human exploration from a view above the Earth or from space. Since November 2, 2000, astronauts and cosmonauts have lived without a break aboard the International Space Station.

For those 7,300 days, 241 individuals from 19 countries were hosted by the $150 billion orbiting laboratory, and more than 3,000 research experiments were carried out there.

Even then, all good things have to come to an end. NASA's ISS was cleared for flying until at least 2028, but the station is beginning to display its age. NASA may deorbit the station at some point in the next 10 to 15 years, smashing it into the southern Pacific Ocean.

But other residential stations, most of them planned and constructed by private companies, are expected to take their place.

Some of these businesses, such as Axiom Space and Bigelow Aerospace, aim to expand on the ISS's popularity by incorporating station extensions that could eventually be withdrawn as their own habitats to orbit. Others want to create brand-new space accommodations, like Blue Origin, so big and sophisticated that they will begin to imitate Earth's life.

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(Photo : Pixabay)
SpaceX satellite in orbit

ISS Getting Old

The station has also outlived its 15-year life expectancy. In the last few months alone, the station's Russian side has seen a busted toilet, an oxygen supply system failure, and an air leak.

"All modules of the Russian segment are exhausted," Gennady Padalka, a cosmonaut, told RIA Novosti in October. 

For now, these problems aren't enough to threaten the credibility of the station, but they are warning signs of deterioration.

"I think it's an incredibly reliable and a robust system," Kate Rubins, a NASA astronaut currently on the ISS, said during a press call last month. 

Russian space policy analyst Andrey Ionin said some of the Russian systems on the ISS are getting old, but after so long in orbit, that's to be expected. The crew is trained to deal with issues, he said.

In 1998, the first parts of the ISS were launched into space, hoping that they would last at least 15 years. The space station's mission extended to 2024 and is proposed to be extended to at least 2028.

Private Companies to Attach Items to the ISS

Axiom Space, a private aerospace corporation in Texas, will construct the first commercial space station. Established in 2016, NASA has already awarded Axiom a contract to build at least one new residential, commercial module attached to the current space station. Then, once the ISS retires, the module will potentially detach to become an autonomous orbital outpost, along with any others that Axiom has added in the next few years.

Bigelow Aerospace, founded by real estate billionaire Robert Bigelow in 1999, is another business with similar ambitions. Since 2016, the Bigelow Expandable Activity Module (BEAM) has been attached to the station. The company has already sent a working version of its inflatable ISS module to space. It's used for storage at the moment.

Another company is working on a concept of a three-story inflatable space habitat, the Sierra Nevada Corporation. Its design will either connect to or act as a lunar base at the space station. The facility might also feature a microgravity garden that could supply fresh produce to space travelers, known as the Broad Inflatable Fabric World, or LIFE.

The Senior Vice President of Sierra Nevada, Janet Kavandi, is also a former NASA astronaut. She told Business Insider that the inflatable habitat might serve several spatial purposes, including "a manufacturing facility, a hotel that may be of interest to some people, or an observatory."

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