Starship "transforms" into a space station? Are you looking forward to super-strong interstellar flight?

Recently, NASA signed the Space Act Agreement, which shows that the "Starship" of SpaceX, which has attracted much attention in the aerospace industry in recent years, will usher in a new bright future. NASA plans to transform the "Starship" that enters the Earth's orbit into a low-Earth orbit space station, which is expected to be put into operation in the 2030s.

Rockets turn into space homes

Starship is a super-heavy launch vehicle being developed by SpaceX. It is the world's first two-stage fully reusable heavy launch vehicle. As early as 2016, Musk demonstrated the interstellar transportation system and its Mars immigration plan, in which the core transportation tool is Starship. Musk believes that by utilizing the Starship's large carrying capacity and fully reusable characteristics, the cost of interstellar flight will be greatly reduced.

The rendering of the second stage of the "Starship" transformed into a space station

According to Musk's original vision, humans will achieve at least two cargo ship landings on Mars before 2022, and achieve cargo + manned landings in 2024. Two manned spacecraft will send the first batch of people to Mars, and two cargo ships will be responsible for delivering supplies, and on this basis, a Mars colony will be gradually established.

Due to a series of difficulties in reality, this idea can no longer be realized on time. However, on April 20, 2023, Beijing time, SpaceX conducted its first "Starship" flight test. Although after the combination ignited and took off, due to the abnormal operation of multiple engines during the flight, the speed and altitude seriously deviated from the flight profile, and the rocket body eventually exploded and disintegrated, the 239 seconds of flight of the combination still proved that this behemoth can work and enter space.

According to the data published on the official website of SpaceX, when the "Starship" is fully reused, its low-Earth orbit carrying capacity is 150 tons; when it is used once, its low-Earth orbit carrying capacity is 250 tons. The "Starship" has a diameter of about 9 meters and a height of about 119 meters. The total takeoff mass of the rocket is about 5,000 tons, and the maximum takeoff thrust is 7,260 tons. It is much larger than the Saturn V rocket, and its takeoff weight is about 1.7 times that of the latter.

Coincidentally, the first American space station orbiting the Earth, Skylab, was built from the third stage of the Saturn V rocket, making full use of the remaining materials from the Apollo program.

Thanks to the huge size of the Saturn V, the Skylab is 36 meters long, 6.7 meters in diameter, weighs about 77 tons, and has a volume of 368 cubic meters, far exceeding the Soviet Union's Salyut space station of the same period. The Skylab was built quite "luxuriantly", including an orbital work module, a transition module, a multi-purpose docking module, a solar telescope, etc. The living facilities were also very well considered, with 11 food storage containers and 5 food freezers, which could store 907 kilograms of different types of hot and cold food.

The second-stage Starship spacecraft of the Super Heavy - Starship, which is planned to be transformed into a space station, is a reusable orbital-class spacecraft, 50 meters high, 6.61 meters in diameter, with a total weight of about 1,200 tons and a structural dry weight of about 125 tons. It can send 100 people to the moon or Mars at a time.

SpaceX said that it could greatly increase the habitable volume of the Starship space station by converting the propellant tank of the Starship spacecraft into a living space for astronauts, just like the Skylab. SpaceX claims that the habitable volume of the Starship spacecraft is 1,000 cubic meters, which will exceed the entire volume of the International Space Station.

There are many hardships before advancement

NASA's plan to transform the Starship into a space station can actually be traced back to its Commercial Space Capability Collaboration Program launched in 2014. The program is implemented under the unfunded Space Act and aims to achieve minimal government resource investment at the expense of structured sharing of NASA's existing expertise, to promote and form the vital capabilities needed for a strong commercial low-Earth orbit economy.

The core of this cooperation is that NASA provides existing professional technical knowledge, reviews and data to selected companies free of charge to help them develop new technologies, and each company will realize its capabilities through self-raised funds and develop low-orbit economy. The first round of cooperation companies of this plan include SpaceX and other four companies.

In June 2023, NASA released the second round of the Commercial Space Capability Collaboration Program, continuing to promote commercial space applications through the sharing of NASA's technical expertise, assessments, lessons learned, technology and data. In this round of the program, NASA selected seven American companies, including SpaceX, to meet future commercial and government needs and promote the development of manned spaceflight and commercial low-Earth orbit economies.

SpaceX is responsible for developing an integrated low-Earth orbit architecture, which includes "Starship" as a transportation system and low-Earth orbit space destination element, supported by super heavy rockets, Dragon spacecraft and Starlink constellation, and contains combined capabilities including manned and cargo transportation, communications, operations and ground support.

This time, NASA and SpaceX reached an agreement to complete the product design review of the "Starship" low-Earth orbit manned space station in the fourth quarter of 2028, and identified 13 milestone nodes from 2023 to 2028. These are also the technical challenges that need to be overcome for the "Starship" to be transformed into a space station.

The first is the "Starship" orbital test flight, that is, the successful launch of the Starship spacecraft using a super-heavy booster. The next challenges to be overcome are the first launch of the "Starship" with a payload, the successful recovery of the "Starship", the verification of propellant on-orbit storage, the verification of "Starship" on-orbit service/recovery/docking, the verification of long-term manned operation in low orbit, the verification of the full process of "Starship" launch/orbit entry/landing, the verification of "Starship" low-orbit transportation and living capabilities, and the verification of "Starship" low-orbit manned space station capabilities.

If everything goes well, "Starship" will officially transform into a space station operating in low-Earth orbit by the end of 2028.

Imagine a bright future

People have long had wonderful fantasies about orbital space stations, such as space tourism, space hotels, space vacations, etc. However, due to the high cost of space launches and the limitations of launch vehicle capabilities, the living area of ​​previous space stations was very small. Even the most spacious international space station in the world has an internal volume of only 915.6 cubic meters, which is equivalent to a 320-square-meter house with six astronauts living there. It can only be considered a "well-off family."

The rendering of the second stage of the "Starship" transformed into a space station

At present, the main force of space consumption is still the extremely wealthy. Since American businessman Dennis Tito became the first space tourist in 2001, wealthy people from all over the world have begun to join in. In the following 8 years, another 6 space tourists have boarded the International Space Station, spending tens of millions of dollars.

Spending so much money but being squeezed into such a small place is indeed not conducive to the expansion of the space tourism market and the sustainable development of the industry. The space station transformed from a starship can easily reach a volume of 1,000 cubic meters, and can even be mass-produced and launched into orbit. Then, in the future, a series of luxurious space resort hotels will appear in low-Earth orbit, and there should be no shortage of guests to stay.

When the technology for transforming "Starship" into a space station matures, driving a "Starship" to the moon or Mars will no longer be a difficult task. Tourists can even eat hot pot and sing songs and arrive at their destination without realizing it.

Of course, no matter how beautiful the future is, it still needs to be realized through realistic actions step by step. The most urgent thing for SpaceX at present is to achieve the successful first flight of the Super Heavy Starship as soon as possible.

According to the U.S. Federal Aviation Administration's official website on September 8, the investigation into the Starship's first flight accident has been completed. The final investigation report lists multiple root causes for the failure of the first flight and requires SpaceX to take 63 corrective measures to prevent the accident from happening again. The measures include redesigning rocket hardware to prevent leaks and fire accidents, redesigning the launch pad to improve its stability, introducing more reviews during the design process, conducting more analysis and testing of key safety systems and components including autonomous flight safety systems, and using more change control strategies.

Currently, SpaceX is implementing all corrective measures and applying to the Federal Aviation Administration for a license modification. After meeting all safety, environmental and other regulatory requirements, the Starship can resume flying. (Author: Yu Yuanhang, Image source: SpaceX, Checkpoint expert: Jiang Fan, deputy director of the Science and Technology Committee of China Aerospace Science and Technology Corporation)