Why can the Chinese space station only accommodate three people, while the International Space Station can host over ten? Is it really a matter of technological inferiority? 為啥中國空間站只能上3個人，國際空間站卻能達到十幾人？到底是誰技不如人?

To put it plainly, the difference is that ours is like a private villa, while the International Space Station is more like a shared apartment. The Chinese space station was built by us, allowing us to maximize its use for our own purposes. In contrast, the International Space Station is shared among multiple countries, so they have to make do with crowding in.

First, let’s talk about the直观 differences in scale. The International Space Station was built through the collaboration of 16 countries, with a total mass of 420 to 450 tons, a pressurized volume of 916 to 1,005 cubic meters, a length of 109 meters, and a width of 73 meters. Its internal modules are diverse and varied.

For instance, the U.S. Destiny module, the Russian Zvezda service module—each country needs its own space to house its equipment. This requires reserving significant room for astronauts from various countries to take turns on duty.

In contrast, our space station has a total mass of 100 tons, a length of 55.6 meters, a pressurized volume of 340 cubic meters, and a habitable volume of 122 cubic meters. It consists of just three modules: the Tianhe core module, the Wentian lab module, and the Mengtian lab module. All were designed by us, with a compact layout and functions allocated as needed, leaving no extra space wasted.

The International Space Station is like a large, bustling but chaotic compound, while ours is like a well-decorated small apartment—sufficient for our needs. This isn’t a matter of technological backwardness but rather a difference in strategy. The International Space Station must balance the interests of multiple parties, with modules of varying standards, making maintenance cumbersome. Our space station, however, is uniformly planned, making it much more efficient.

The International Space Station once hosted a record of 13 people, but its usual capacity is seven. Our standard capacity is three, though it can temporarily accommodate six during crew rotations. The gap lies here—it’s not that we can’t fit more people, but there’s no need to cram them in.

The root of the crew configuration lies in usage requirements. The International Space Station typically hosts seven people because each country needs to send representatives to manage its own section. U.S. astronauts monitor equipment in the Destiny module, Russians repair the Zvezda module, and European and Japanese astronauts each have their own duties. Tasks are fragmented like a puzzle, and no one can be missing.

Our space station usually hosts three people, based on the actual volume of experiments. In December 2022, during the handover between Shenzhou-14 and Shenzhou-15, six people stayed for a few days, proving that the capacity is sufficient. However, there’s no need to keep it fully occupied year-round. Why? Because the 16 experiment racks follow uniform standards, and three people can divide the work: one managing life sciences, one handling materials research, and one maintaining systems, ensuring smooth collaboration.

The International Space Station’s equipment has poor compatibility, requiring crew members to分散精力 learning various operations, which reduces efficiency. Simply put, our space station is like our own land—we can farm it as we wish. The International Space Station is like a shared property, where everyone’s needs must be considered, so crowding is unavoidable.

The resupply capability directly reveals the differences in design philosophy. The International Space Station, with its larger crew, has higher consumption and relies on various countries taking turns to deliver supplies. Russia’s Progress cargo ship carries 2.5 tons per trip, making several flights a year. The U.S. cargo ships have a capacity of up to 3 tons, requiring multiple people to collaborate during unloading. The total operational cost is high, ranging from $3 to $4 billion annually, shared among partner countries.

Our Tianzhou cargo ship, on the other hand, can carry 6.5 tons per trip. By 2025, Tianzhou-9 will support three people with nine months of supplies and 1.4 tons of propellant. With lower launch frequency, it saves both money and effort. Key to this is our advanced environmental control and life support system. We can convert exhaled carbon dioxide into oxygen and purify urine and sweat into drinking water, with a utilization rate of over 90%, basically eliminating worries about basic supplies.

為啥中國空間站只能上3個人，國際空間站卻能達到十幾人？到底是誰技不如人？

說的直白一些，差別就是我們是私人別墅，而國際空間站就是群租房（公寓），中國空間站是我們自己造的，可以最大化讓自己人利用，而國際空間站就不行，是多個國家共用的，他們只能擠一擠。

先說體量上的直觀區別。國際空間站是16個國家合力搞出來的，總重420噸到450噸，壓艙體積916立方米到1005立方米，長度109米，寬度73米，內部模塊五花八門。

美國的命運艙、俄羅斯的星辰服務艙，每個國家都得佔一畝三分地，放自家設備。這就得預留大把空間給各國航天員輪流值班。

反觀咱們的空間站，總重100噸，長度55.6米，壓艙體積340立方米，可居住部分122立方米，就三個模塊：天和核心艙、問天實驗艙、夢天實驗艙，全是自己設計，布局緊湊，功能按需分配，沒那麼多閑地方浪費。

國際空間站像個大雜院，人多熱鬧但亂……，咱們像精裝修小戶型，夠用就好。這不是技術落後，而是策略不同。國際空間站得平衡多方利益，模塊標準不一，維護起來費勁，咱們統一規劃，效率高多了。

國際空間站歷史最高13人，但常態7人；咱們標準3人，短時能到6人。差距就在這兒，不是裝不下，是沒必要硬塞。

人數配置的根源在於使用需求。國際空間站常駐7人，因為各國得派代表管自家地盤，美國航天員盯命運艙設備，俄羅斯人修星辰模塊，歐洲和日本的也各司其職，任務碎得像拼圖，少誰都不行。

咱們空間站平時3人，基於實際實驗量，2022年12月神舟14和15交接時6人住了幾天，證明容量夠，但沒必要常年滿員。為什麼？因為16個實驗櫃統一標準，三人分工就行，一個管生命科學，一個搞材料研究，一個維護系統，協作順溜。

國際空間站設備兼容差，成員得分散精力學各種操作，效率打折。說白了，咱們是自家地，想怎麼種怎麼種，國際空間站是公攤房，得顧大家感受，擠點也沒轍。

補給能力直接暴露設計思路的分歧。國際空間站人多消耗猛，得靠各國輪番送貨，俄羅斯進步號貨船每次2.5噸，一年飛好幾趟；美國貨船上限3噸，卸貨時得多人協作。總運營成本高，每年30到40億美元，分攤給夥伴國。

咱們天舟貨船單次6.5噸，2025年天舟九號支持3人9個月物資外加1.4噸推進劑，發射頻次低，省錢省力。關鍵是環控生保系統先進，咱們能把呼出二氧化碳轉氧氣，尿液汗液凈化成飲用水，利用率90%以上，基本不愁基礎補給。