With an earth-shaking roar at 9:22 pm on Wednesday, China’s Tianzhou-6 cargo ship blasted off on a resupply mission to the country’s Tiangong space station, the first since the station was completed in November.

The uncrewed ship – carrying 7.4 tons of fuel, food and other supplies – was launched on top of a Long March-7 rocket from the Wenchang spaceport in southern China’s Hainan island, according to the China Manned Space Agency(CMSA).

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After several minutes, Tianzhou-6 separated from the carrier rocket and entered its designated orbit. The solar panels of the cargo craft then unfolded.

The cargo ship’s voyage to the orbiting space station took about 6? hours, before it carried out a fast, automated rendezvous and docked with the aft port of the Tianhe core module of China"s space station at 5:16 a.m. Beijing Time on Thursday, and entered integrated flight phase with the space station.

Tianzhou-6 is carrying about 260 packages with a combined weight of nearly 5.8 metric tons, including living necessities enough for a three-member crew for 280 days.

The cargo craft will supply for Tiangong"s current crew, the three astronauts of the Shenzhou-15 mission, as well as the future Shenzhou-16 astronauts. The delivery will supply astronauts Fei Junlong, Deng Qingming, and Zhang Lu for the final weeks of their six-month stay on board Tiangong, as well as a new three-person crew for theShenzhou-16 missionwho will arrive at the station later this month.

The Tianzhou-6 cargo ship contains a 22.5-cubic-meter cargo compartment with 50 lockers to place daily necessities for the taikonauts and equipment needed for in-orbit experiments. The crew of Shenzhou-15 is scheduled to enter the Tianzhou-6 on Friday morning to unpack their space package, and carry out planned tasks such as cargo transfer and other related operations.

What’s in the package?

First of all, the taikonauts are about to enjoy a hearty fruit feast in space, because the cargo ship is packed with 70kg of fruit - more than twice the amount of previous Tianzhou missions.

According to media reports, the fresh fruit carried by Tianzhou-6 include Fuji apples from Shannxi province. Fruit that"s convenient to eat, rich in nutrition with long storage life is always the preferred choice. In previous missions, apples, bananas and grapes were sent.

“In the future, we plan to send a large refrigerator up there so that astronauts can have fresh fruit as well as frozen food,” said Wang Ran, the chief designer of the cargo spacecraft system at the China Academy of Space Technology.

“If they want to eat fried steaks, the beef needs to be kept frozen all the way from Earth to orbit. Our capabilities will gradually improve to ensure a better environment for the astronauts,” Wang told state broadcaster CCTV on Tuesday.

Besides food, the cargo ship also delivers other daily necessities such as clothes, drinking water, holiday and sanitation supplies, as well as experimental equipment for the taikonauts.

Upgraded payload capacity

Tianzhou-6 marks the first mission for a new and improved version of China"s robotic freighter. With a designed life span of more than a year, a Tianzhou cargo craft has two parts —a smaller lower part as its propellant module and a larger upper part as the cargo module.

Such vehicles are 10.6 meters long and 3.35 meters wide. It is the world"s best space cargo transporter when it comes to carrying capacity, as more than half of its liftoff weight can be used for payloads, according to its designers.

With a maximum launch mass of 14 tons, the Tianzhou-6 spacecraft now has a payload ratio of 0.53, the best of its kind in the world. The payload ratio refers to the proportion of cargo weight to the total weight of the whole spacecraft. The higher the ratio, the stronger the cargo capacity of the spacecraft.

Bigger payloads also mean the frequency of futureresupply missionscan be reduced from two per year to three every two years. The launcher"s developer, the China Academy of Space Technology (CAST), under the state-owned space giant China Aerospace Science and Technology Corporation (CASC), said that the cargo spacecraft system expands the fully sealed cargo spacecraft into two types: A standard type with eight storage boxes and an enhanced type with four storage boxes, which can be selected according to refueling requirements on the space station.

The improved fully sealed cargo spacecraft increases the cargo loading capacity of the sealed cabin, providing astronauts with supplies that can sustain them for longer periods of time. This reduces the launch frequency of the cargo spacecraft from four launches in two years to three launches in two years, effectively improving the overall efficiency of the space station.

With its expanded capacity, the Tianzhou-6 is considered a significant improvement over the older model, able to deliver its payload more efficiently, at a lower cost.

Li Zhihui, deputy project manager of Tianzhou-6, said that compared with its predecessors, Tianzhou-6 has a remarkable improvement — it has more space in the airtight payload containers because engineers have redesigned its interiors and moved some devices from the cargo cabin to the propulsion section. After the modifications, the cargo ship is capable of holding an extra 500 kg of mission supplies.

The Tianzhou-6 cargo craft is the first of a new batch of China"s cargo ships – from Tianzhou-6 to Tianzhou-11 – to boost their loading capacity from the previous 6.9 tons to 7.4 tons, after the volume of the airtight cabin (cargo cabin) has been increased by 20 percent.

Jia Dongyong, chief mechanical designer for the Tianzhou cargo spacecraft system at CAST, said the Tianzhou-6 cargo ship is the most capable space cargo ship currently in service.

Tianzhou-6"s launch is of great significance for the technical verification of the new batch of improved cargo spacecraft and the mass production of subsequent spacecraft, Jia added.

Aside from daily supplies, another important mission for Tianzhou-6 is to replenish propellants for the space station. Tianzhou-6 is carrying about 1.75 tons of propellant, 700kg of which will be transferred to Tiangong.

Since it has entered the application and development stage, China"s space station no longer requires large amounts of propellant for altitude adjustment. Therefore, the Tianzhou-6 cargo ship has reduced the number of its propellant tanks from eight to four compared with its predecessors, leaving room for more payload.

China completed construction of the three-module Tiangong in late 2022. Tianzhou-6 is the first mission of the operational phase of Tiangong. The country aims to keep the station permanently occupied for at least a decade, with crews of the three astronauts spending six months aboard at a time.

TheTianzhou-5 cargo ship, which undocked fromTiangonglast Friday to make way for the arrival of Tianzhou-6, is in flight in a separate orbit. It will redock with Tiangong after Shenzhou-15 leaves.

Its return will not only provide extra storage and operation room for the space station, but will also expand Tiangong into its largest configuration with three major modules, two cargo ships and one crewed ship.

This added capacity allows China to now launch resupply missions to Tiangong every eight months on average, as opposed to every six months with previous Tianzhou vessels.

Tianzhou-6 will be part of a series of space station operations over the next couple of months. Near the end of May, the Shenzhou-16 crew – which has not yet been announced – will join the Shenzhou-15 astronauts. The six will then spend several days together before the Shenzhou-15 crew returns to Earth in early June, followed by the Shenzhou 17, which is expected to lift off toward the end of the year.

For future missions, China has plans to launch the Xuntian telescope, expand the current space station, train international astronauts, and develop a new-generation reusable transportation system between the Earth and the low-Earth orbit.

Working better and better with Long March-7 rocket

The Tianzhou-6 cargo craft is the first spacecraft to visit the Shenzhou-15 crew in orbit and the ninth spaceship to visit the Chinese space station. It is worth mentioning that the freighter was launched atop a Long March-7 carrier rocket, the country"s new-generation medium liquid-propellant carrier rocket with high reliability and safety.

With a total length of 53.1 meters and a diameter of 3.35 meters, the rocket is bundled with four boosters and has a takeoff weight of nearly 600 tons and a payload capacity of about 14 tons to low-Earth orbit.

Like many other programs in the spaceflight world, the Chinese space program builds up on heritage knowledge and hardware from the defense sector. Examples of this are the veteran rockets in the family, namely the Long March 2, 3, and 4 — these still have active variants — which derive from the Dong Feng 5 intercontinental ballistic missiles (ICBM).

After decades in service, these hypergolics-propelled launch vehicles are finally, though slowly, heading for retirement. The Long March-7 rocket, which is the biggest serving carrier, is on a path to take over most of the launch activity carried out by the older Long Marches. In the future it should perform both cargo and crew launches supporting China’s manned program, as well as commercial flights.

The Tianzhou-6 mission is the 7th launch for the Long March-7 rocket. In addition to undertaking cargo launch missions to the space station, the Long March-7 rocket will also launch low- and medium-orbit satellites in the future.

Meanwhile, Tianzhou-6 brings updated scientific research equipments to the space station. There are also 98 packages of science payloads, with a combined weight of 714 kg. These contain new equipment, spare parts and experiment-related materials.

The payloads will be used in 29 scientific experiments and technological tests in disciplines such as life sciences, biology and fluid physics in microgravity, as well as combustion and material sciences.

整船物资有效装载容积扩大20%，“带货”实力再升级；长征七号运载火箭与天舟货运飞船六度携手，测发时间进一步缩短、流程可靠性进一步提升；将聚焦空间生命科学与生物技术等领域，开展29项科学实验和应用试验……

5月10日21时22分，伴随着震天动地的轰鸣声，一道耀眼的光柱划破夜空，搭载天舟六号货运飞船的长征七号遥七运载火箭点火发射，穿云破雾，直入云霄，中国空间站建成后的第一艘“货船”正式起航。

约10分钟后，天舟六号货运飞船与火箭成功分离并进入预定轨道。

椰林间，滨海处，文昌航天发射场内外欢呼声此起彼伏，人们热烈庆祝我国载人航天工程进入空间站应用与发展阶段的首次飞行任务告捷。

之后，飞船太阳能帆板顺利展开工作，发射取得圆满成功。据中国载人航天工程办公室11日消息，天舟六号货运飞船入轨后顺利完成状态设置，于北京时间2023年5月11日5时16分，成功对接于空间站天和核心舱后向端口。根据计划，神舟十五号航天员乘组将在12日上午8点多打开天舟六号舱门来“拆快递”。

天舟六号货运飞船是我国空间站应用与发展阶段的首发航天器，是改进型货运飞船的首发船，也是天舟六号到天舟十一号组批生产的首发货运飞船，将为神舟十六号和神舟十七号两个乘组先行送去“粮草”和“辎重”，承担着打好中国载人航天工程空间站应用与发展新阶段开局之战的重任。

天舟六号为中国人的太空之家“补货”，新包裹里藏着哪些惊喜？此次的“天舟快递”有何升级？发射任务有哪些看点？

“带货”能力强

天舟六号最大的特点是吨位更高，能装下更多货物。凭借货物装载能力首次突破7吨，天舟六号一跃成为世界上现役货物运输能力最大、在轨支持能力最全面的货运飞船。

天舟六号里有什么？

飞船装载了神舟十六号和神舟十七号6名航天员在轨驻留消耗品、推进剂、应用实（试）验装置等物资。

我国天舟货运飞船采用货物舱和推进舱两舱设计，货物舱用于运输各类物资，推进舱为飞行器提供动力、能源与通信功能，并装载空间站补加推进剂。

历次天舟货运飞船升空的装载情况，是由空间站不同阶段任务和科学需求决定的。本次任务，天舟六号也根据新阶段新需求做出了灵活调整。

一方面，到了空间站应用与发展阶段，空间站姿态变化调整相对变少，推进剂消耗也会减少。另一方面，随着天舟六号升级改进，推进舱腾出了一部分空间来放置原货物舱设备，货物舱就有了更大的容积装货，方便携带更多物资。

中国航天科技集团五院货运飞船系统主管设计师董圣然介绍，通过改进，天舟六号密封舱货物装载空间提升了24%，装载能力由5.5吨增加至6.7吨；天舟六号整船物资装载能力由6.9吨提高至7.4吨，上行载货比由0.51提高至0.53。

“带货”能力的大幅提升，使得货运飞船每发射一次，能为航天员提供更久更充足的物资保障支持。为提高货物运输能力，本次任务天舟六号货运飞船进行了优化改进，将货运飞船发射需求由1年2次优化为2年3次，有效降低了运输成本。

本次任务还有一个显著亮点，就是天舟六号及后续型号中，国产型号规格比例和数量比例均有大幅提升，实现了关键元器件100%国产化。研制队伍通过推进系统配置优化工作，在提高可靠性的同时降低了成本，满足了上行遥控要求及下行图像和载荷数据的需求。

空间“装修”新

天舟六号如何改进？主要对货物舱和推进舱做了优化设计。

科研人员将天舟六号货物舱的后锥段，由原来的非密封舱改为密封舱，新增的“货架”大大拓展了货物舱的存储空间。同时，原来位于货物舱后锥段的仪器设备，为了寻找新的“座位”，则全部下移至推进舱内。

腾挪空间，说起来容易，做起来难，处处考验着航天科研人员的技术功底和匠心巧思。

面对数十台新增的仪器设备，推进舱必须把这些“乘客”安排稳当。

“在推进舱构型尺寸不变的情况下，舱内的配套设备增加了近50%，新增的大多属于外形尺寸大、插件布局密、关联设备多、线缆直径大的设备，除了要满足设备安装后整体结构力学平衡需求，还要预留足够的操作空间，用于电缆插接以及电缆网敷设、固定绑扎，以及满足高标准的安全性、维修性要求。”中国航天科技集团八院飞船型号副总师曹俊生介绍。

天舟六号货运飞船的成功改进，将全密封货运飞船拓展为标准型（8个贮箱）和改进型（4个贮箱）两种状态。后续，将根据空间站补加推进剂的上行需求，由不同型谱的天舟货运飞船执行任务，为我国空间站长期稳定运营提供充足物资保障。

今年距离天舟货运飞船首飞已有6年。时间拉回至2017年4月20日，天舟一号在文昌航天发射场发射升空，验证了货物运输和推进剂在轨补加等多项关键技术，为我国载人航天工程“三步走”发展战略中第三步空间站研制建设奠定了坚实基础。

入轨精度高

本次任务是2023年我国载人航天工程任务的首次发射。搭建天地运输走廊、担纲托举天舟重任的“货运专列”，依然是长征七号火箭。

长征七号运载火箭是天舟货运飞船的“老搭档”。它是为满足我国载人空间站工程发射货运飞船需求，以及兼顾发射卫星等其他任务需求而研制的新一代高可靠、高安全的中型运载火箭，其入轨精度也是现役运载火箭中最高的，偏差不超过4秒。

从首飞算起，长征七号火箭尽管连战连捷，仍在坚持技术创新和全方位改进。中国航天科技集团一院长征七号运载火箭副总设计师马忠辉介绍，本次任务中，研制队伍对火箭发动机等产品进行了可靠性提升改进，进一步消除了薄弱环节；在测发流程方面，优化了地面测控软件，进行了单机、系统和全箭验证，测发流程可靠性得到进一步提升。经过流程的科学规划和优化，发射场测发时间从7年前的近40天缩短到了如今的25天。

后续，长征七号火箭还将以每年1到2次的发射频率，为我国空间站正常运转提供物资保障。在满足空间站货运任务的同时，长征七号火箭未来还计划发射中低轨卫星，拓展卫星发射市场。

截至目前，我国所有的天舟货运飞船都是从文昌航天发射场点火升空。2016年长征七号运载火箭在文昌航天发射场首飞成功，标志着我国自主设计建造的新一代航天发射场正式投入使用。

本次任务中，空间应用系统也有相关部署。据空间应用系统副总设计师、中国科学院空间应用工程与技术中心研究员吕从民介绍，空间应用系统通过天舟六号货运飞船上行实（试）验载荷、实验单元及样品、共用支持类设备、实验耗材和备品备件等，共计98件产品，总重量约714公斤。天舟六号与空间站完成快速交会对接后，由航天员将上述产品转运至空间站舱内，按飞行任务规划陆续开展空间生命科学与生物技术、微重力流体物理与燃烧科学、空间材料科学、空间应用新技术试验等4个领域共29项科学实验和应用试验。

Executive Editor: Sonia YU

Editor: LI Yanxia

Host: Stephanie LI

Writer: Stephanie LI

Sound Editor: Stephanie LI

Graphic Designer: ZHENG Wenjing, LIAO Yuanni

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