One of China’s workhorse rockets just exploded in flight

中国主力火箭之一在飞行中发生爆炸

One of China’s most used rockets, the Long March 7A, exploded a little more than a minute after lifting off on Monday evening, local time. The medium-lift rocket’s payload was classified, but it was believed to be a military communications satellite. The rocket’s liftoff from Wenchang Space Launch Site appeared to be nominal, but publicly captured videos (such as this one) showed that the rocket’s first stage exploded about 1 minute and 20 seconds into flight. The Long March 7A rocket was developed by the China Aerospace Science and Technology Corporation and is operated by the state’s space agency. As of Monday night in China, state officials have not commented on the explosion.

中国最常用的火箭之一——长征七号甲运载火箭，在当地时间周一晚间升空后仅一分多钟便发生爆炸。这枚中型运载火箭的载荷属于机密，但据信是一颗军事通信卫星。火箭从文昌航天发射场起飞时看起来一切正常，但公开拍摄的视频（如这一段）显示，火箭在飞行约1分20秒时，第一级发生了爆炸。长征七号甲火箭由中国航天科技集团研发，并由国家航天局运营。截至中国周一晚间，官方尚未就此次爆炸发表评论。

Was it an engine issue? Based on the timing of the explosion, it occurred during the flight of the first stage of the vehicle, likely around the time of maximum dynamic pressure as the rocket accelerated through the lower atmosphere. It’s possible that the vehicle’s flight was ended by on-board ordnance known as a “flight termination system,” which ignites when the vehicle veers off course.

是发动机问题吗？根据爆炸发生的时间点判断，事故发生在火箭第一级飞行期间，很可能是在火箭加速穿过低层大气、处于最大动压点附近时发生的。也有可能火箭的飞行是被机载的“飞行终止系统”所终结，该系统会在火箭偏离航线时启动。

China’s state-operated launch industry has had considerable success in the last half-decade as it has grown its annual launch total to 50 or more flights per year. During that time, it has only suffered a handful of launch failures. Due to the uncertainty surrounding the cause of Monday’s failure, the significance of the problem is difficult to ascertain. Given the closed nature of China’s state-operated space program, it may never be clear what caused the rocket to explode.

在过去五年中，中国的国有航天发射产业取得了巨大成功，年发射次数已增长至每年50次以上。在此期间，仅遭遇过少数几次发射失败。由于周一事故的原因尚不明确，问题的严重性难以断定。鉴于中国国有航天计划的封闭性，导致火箭爆炸的真正原因可能永远不会公开。

However, if the cause is due to the first stage’s main engine, the YF-100, there could be broader implications for China’s space program. The YF-100 is by far the most commonly used rocket engine in China’s space program. The engine, fueled by liquid oxygen and kerosene, has a thrust of 270,000 pounds at sea level. It has powered the Long March 7 and newer Long March 7A variant for the last decade. This rocket performs a variety of tasks for China’s space program, from communications satellite launches to boosting the Tianzhou cargo spacecraft that ferries supplies to the Chinese space station in low-Earth orbit.

然而，如果事故原因是由于第一级的主发动机——YF-100所致，那么这对中国的航天计划可能会产生更广泛的影响。YF-100是目前中国航天计划中使用最广泛的火箭发动机。该发动机以液氧和煤油为燃料，海平面推力为27万磅。在过去十年中，它一直为长征七号及其改进型长征七号甲提供动力。该系列火箭为中国航天执行多种任务，从发射通信卫星到运送为中国空间站补给物资的天舟货运飞船。

The broader concern for China’s space program is that the YF-100 engine also powers other rockets. As many as nine Chinese rockets, from the Long March 5 to Long March 8 vehicles, used various amounts of YF-100 engines. Even new rockets, such as the Long March 10, use modified variants of the YF-100 technology.

中国航天计划更广泛的担忧在于，YF-100发动机也为其他火箭提供动力。从长征五号到长征八号，多达九种中国火箭使用了不同数量的YF-100发动机。即便是长征十号等新型火箭，也使用了YF-100技术的改进版本。

If this issue is engine-related, it could delay one of China’s most important launches for the rest of the year. The country’s ambitious Chang’e 7 robotic mission to the Moon was due to launch on a Long March 5 rocket about two weeks from now. That rocket’s boosters are powered by YF-100 engines. The Chang’e 7 mission is an important component of China’s lunar program as the vehicle combines an orbiter, lander, rover, and mini-hopper. It is bound for the area near Shackleton crater, in the vicinity of the South Pole of the Moon. It would be the first rover by any country ever sent to explore this region. Both China and NASA are racing to establish operations at the potentially resource-rich South Pole of the Moon.

如果这个问题与发动机有关，可能会推迟中国今年最重要的发射任务之一。中国雄心勃勃的嫦娥七号月球探测任务原定于两周后由长征五号火箭发射。该火箭的助推器正是由YF-100发动机提供动力。嫦娥七号任务是中国探月工程的重要组成部分，该探测器集成了轨道器、着陆器、巡视器和飞跃探测器。它的目标是月球南极附近的沙克尔顿陨石坑区域。这将是人类历史上首个被派往该区域进行探测的月球车。目前，中国和美国国家航空航天局（NASA）都在竞相在资源潜力巨大的月球南极建立基地。