China’s first satellite, Dong Fang Hong 1 (DFH-1, DFH = “The East is Red”), was a symmetrical 72-faced polyhedron 1 m in diameter, with an orbital mass of 173 kg. The satellite space-frame consisted the upper and lower hemispherical covers, and a connection section in the middle. Four high-frequency (20 MHz) radio signal antennas were attached symmetrically to the middle connection section. The 3 m-long antennas were folded during launch and then deployed by the centrifugal force of the satellite spin once in orbit. A single 40 cm long VHF radio beacon antenna was attached to the top of the satellite. The 5 cm radio transponder and 10 cm UHF radio beacon antenna were attached to the middle section of the satellite.
The satellite was originally to be powered by both solar panels attached to the satellite surface and silver-oxide batteries, but only the batteries were adopted on the Dong Fang Hong 1 mission in order to simplify the design. The batteries were sufficient to power the satellite for 20 days, while in reality the satellite remained operational for 28 days.
The satellite was spin-stabilised at a rate of 2 rounds per second. Passive thermal-control was used to maintain the temperature inside the satellite between 5 to 40°C. This was achieved using a multi-layer insulation inside the space-frame and an anodised aluminium coat on the outside surface to increase the reflection of sunlight. Electric heater was used to maintain the temperature for some more sensitive components.
The satellite was designed to broadcast radio signals of a patriotic song, The East is Red, in 20 MHz HF radio signal from the Earth orbit. As well as being ‘heard’, the Chinese political leadership also demanded the satellite to be ‘seen’ by people around the world – not an easy task for something of this size in orbit. Chinese space engineers came up with a solution by fitting the third-stage of the launch vehicle with a medal ‘observation skirt’. Once the satellite was deployed, the third-stage flying closely behind in orbit would deploy the skirt to reflect the sunlight, so that it could be observed in the night sky by naked eyes.
529 Factory (Beijing Factory of Scientific Instruments) completed two operational satellites for the Dong Fang Hong 1 mission in March 1970. The two satellites each required 15 separate checkout processes. Despite some faults and quality issues that were identified during the assembly and initial testing, the two satellites were deemed fit for launch.
Launch campaign for the Dong Fang Hong 1 mission began on 1 April 1970, when the two satellites and launch vehicle were delivered from the factories in Beijing to the Jiuquan launch site by railway. The railway transit of the satellites and launch vehicle was shrouded in secrecy and placed under tight security, with two armed soldiers stationed between every two telegraph poles along the entire journey.
Upon arrival at the launch centre, the satellites and launch vehicle were placed inside the processing hall in the technical area (Site 7) 40 km south of the launch site. After four days of examination, the two satellites were certified for meeting the design requirements. On 8 April, the first comprehensive examination on the CZ-1 launch vehicle was completed and one of the satellites was mated with the launch vehicle. By 10 April, the satellite and launch vehicle had passed the second and third checkout examinations.
In the evening of 14 April, all managers of the satellite project, including Qian Xuesen (space programme chief), Li Fuze (launch centre commander), Yang Guoyu (launch centre political commissar), Ren Xinmin (launch vehicle designer) and Qi Faren (satellite designer), were summoned by Premier Zhou Enlai to the Great Hall of the Peoples in Beijing to brief him on the preparation for the Dong Fang Hong 1 mission. Zhou checked every aspect of the launch campaign in detail, including the time when the satellite would pass over the capitals of all friendly countries.
A written report summarising all the details of the launch campaign by Ren and his colleagues was submitted to the Chinese leadership for approval. At 22:00 on 16 April, Premier Zhou phoned the NDSTC headquarters to approve the report and give go-ahead for the rollout of the launch vehicle to the launch pad (Pad 5020).
On 19 April, during the final checkout on the pad, it was noticed that the output power of the satellite’s radio beacon weakened significantly, which would make it harder to track for the ground stations. After some careful examination, the technicians identified that a crimped insulation layer inside the rocket’s upper state disrupted the signals of the radio beacon. After replacing the insulation layer, the issue was resolved.
The launch window was finally confirmed to be around 21:30 local time on 24 April. The weather forecast was favourable for the launch. Fuelling of the launch vehicle with liquid propellants began in the morning on 24 April, and the launch site entered 8-hour countdown. At 15:50, Premier Zhou telephoned the NDSTC deputy chief to confirm that Chairman Mao Zedong had approved the launch. The news was soon cascaded to all teams at the launch site.
At 20:00, the final 60-minute countdown begun. Only 40 minutes before the ignition, it was noticed that the radio transponder was not responding to the ground signal. The mission control requested a 30-min delay of the launch sequence. The radio transponder issue was rectified at 20:28. At 21:00, just when the mission control was about to initiate the 30-minute countdown, the ground tracking station in Hunan informed the mission control that a vacuum tube on its mono-pulse tracking radar broke down and a new tube was fitted at 20:30. However, it would require 40 minutes for the radar to re-calibre.
At 21:05, the mission control finally ordered the 30-minute countdown and ground crew was evacuated from the launch pad. By 21:15, the tracking station in Hunan reported that the issue was almost resolved. At 21:35, the CZ-1 launch vehicle ignited and lifted off from the launch pad. 7 minutes later, the mission control confirmed that the satellite had successfully separated from the launch vehicle and entered the orbit. At 21:50, the National Broadcasting Bureau confirmed to have received the radio signals from Dong Fang Hong 1.
In the afternoon of 25 April, the Xinhua News Agency announced that China had launched its first artificial satellite on 24 April 1970. The satellite was placed into a 439 km by 2,384 km orbit inclined at 68.5 degrees, with a period of 114 minutes. The satellite was 173 kg in mass and broadcasted The East is Redon 20.009 MHz. China had become the world’s fifth spacefaring nation, after the Soviet Union, the United States, France and Japan.