China’s Long March rocket family has suffered two consecutive launch failures within the space of two weeks, a major below to the country’s space plan including the Chang’e 5 lunar sample return mission later this year and the launch of the Tianhe space station module in 2018.
On 19 June, the Long March 3B (Y23) launch vehicle lifted off from Launch Complex 2 of Xichang Satellite Launch Centre shortly after midnight at 00:11 CST (16:11 UTC on 18 June), on what was expected to be a routine mission to deliver a telecommunications satellite named ChinaSat 9A to Geostationary Transfer Orbit (GTO).
The initial phases of the launch mission appeared to have passed smoothly. After the jettison of the launch vehicle’s four liquid boosters, first- and second-stage, its cryogenic third-stage shut down as scheduled to enter a coast phase before a second burn later to insert the satellite into a standard highly-elliptic GTO.Trouble struck when the telemetry data showed the stage entered a negative rolling, which should be compensated with a positive rolling using the stage’s altitude control system. However, for unknown reason an opposite instruction was given to the control system, sending the stage into a spiralling spin out of control.
Fortunately, the ChinaSat 9A satellite remained intact and was eventually separated from the stage. Orbital data showed two objects in an orbit of 193 x 16,357 km with 25.68° inclination, significantly off target and well short of the intended GTO typically 42,000 km on apogee.
Few moments after its orbit insertion, the satellite successfully deployed its solar panel wings and communications antennas, allowing it to establish contact with the ground control. This was critical as it allowed the ground control to command the satellite to manoeuvre to its intended position on orbit using its own propulsion system.
On 5 July at 20:59 CST (12:59 UTC), ChinaSat 9A finally reached its intended position at 101.4°E on Geostationary Earth Orbit (GEO) after 10 orbit adjustment burns. However, traveling over such a long distance using the satellite’s own propulsion came at a cost – it had consumed a significant amount of onboard propellants, originally intended for orbital maintenance burns throughout the satellite’s lifetime, resulting in a reduction in its orbital life expectancy from the designed 15 years to about 5 years.
Determined to not let the failure impact subsequent launch missions, the Chinese space industry was quick in establishing the cause for the launch failure and concluded that the issue was unique to the Long March 3 series only. This conclusion provided the Chinese space managers with some confidence to continue with the Long March 5 (Y2) launch mission in early July.
The Long March 5 is China’s new-generation heavy-lift orbital launch system, capable of delivering up to 25 tonnes of payload to Low Earth Orbit (LEO), or up to 14 tonnes to GTO. The launcher is tasked with the launch of China’s lunar sample return mission scheduled later this year, the launch of the modules for China’s Tiangong space station between 2018 and 2022, and the Mars probe mission scheduled in 2021.
A total of two flight tests carrying only experimental payloads have been scheduled to validate the launch vehicle’s design. The Long March 5 (Y1) was launched in November 2016, carrying a technology demonstration satellite named Shijian 17. Despite an eventful launch countdown and some small glitches, the launch vehicle managed to place its payload onto GTO.The Long March 5 (Y2) launch vehicle rolled out of production line and was delivered to Wenchang Space Launch Centre in late April this year. After a three-month checkout procedure, the assembled launch vehicle and payload stack was rolled out atop the mobile launcher platform to Launch Complex 101 on 26 June. The launch window was finalised as 2 July, with the fuelling of the propellants on the launch pad beginning at 16:30 CST (08:30 UTC) on 1 July.
At 19:23:23 CST (11:23:23 UTC) on 2 July, the Long March 5 (Y2) launch vehicle carrying the Shijian 18 technology demonstration satellite lifted off from its launch pad. The launch mission appeared to have gone as scheduled, with the commentators on live television confirming everything was normal throughout the initial flight. However, the live TV broadcast came to an abrupt end shortly after the second-stage’s first engine cu-off to enter coast phase. Soon after, the Chinese state media finally confirmed that the launch mission had failed.
It was later revealed that trouble began shortly after the lift-off, with telemetry data showing an anomaly with one of the two cryogenic YF-77 engines in the core vehicle’s first-stage. The underpowered launch vehicle soon began to deviate from the planned ascent trajectory, and the first-stage was jettisoned at a much lower altitude than planned. As a result, the second-stage could not gain enough delta-v to enter orbit before its engine shut down. The stage and its payload re-entered the atmosphere over the Pacific.The Long March 5 (Y2) failure has a much wider and more profound impact to China’s space programme than the previous Long March 3 mishap. The country’s most powerful and technologically advanced launch vehicle so far, the Long March 5 is crucial to China’s future space plan in the next decade or so, which includes 1—2 robotic lunar sample return missions, the launch of three space station modules, the robotic Mars probing mission, and potentially a manned lunar landing mission.
The Long March 5 had been in development for over a decade and only became available for test launch last year, almost two years later than originally expected. As a result, it leaves much less time for the rocket to be fully tested before its scheduled missions began later this year, with the Long March 5 (Y3) vehicle already in production at the Tianjin rocket fabrication plant in readiness for the Chang’e 5 mission scheduled for November this year.
According to the original plan, the Long March 5 needs to achieve two successful test launches before it can be used for ‘real’ missions. With the most recent launch failure, the Chinese space planners now face the dilemma between postponing the upcoming missions, and proceeding as planned without another test flight. Traditionally the Chinese space programme favoured a slow but prudent approach to avoid failures. So unless the root cause of the Long March 5 (Y2) mission failure can be identified and isolated very quickly, it is most likely that the Long March 5 (Y3) vehicle will be used for another test flight, pushing the Chang’e 5 mission into 2018 and potentially also having a knock-on effect on the Tianhe 1 mission.
The Chinese space programme has earned high respect within the space community around the world in recent years through a string of eye-dazzling successes. However, the recent two mishaps prove that it too cannot be immune to the high risk and tremendous difficulties involved in the space endeavour. Following the two incidents, there have been callings from both within the Chinese space industry and the wider general public for a re-evaluation of the approach in running the country’s space programme. Some issues being highlighted include a failure to attract the country’s top talents into the space programme due to the obsolete management, and the urgent need for a system reform within the industry.