Ariane 6号火箭首飞到底算不算成功？法国间谍卫星还用它发射吗？【大道消息·航天版】

阿丽亚娜6号是由阿丽亚娜航天公司运营的欧洲消耗性发射系统，由阿丽亚娜集团代表欧洲航天局（ESA）开发和生产。它取代了阿丽亚娜5号，成为阿丽亚娜运载火箭系列的一部分。承载了欧洲国家希望摆脱对美俄运载火箭依赖，重新具备自主发射入轨能力的希望载具。

阿丽亚娜6号的首次任务于欧洲中部时间7月9日21：00从圭亚那航天中心发射升空。飞行仅一个多小时，在短短九秒内成功执行了三次有效载荷分离事件。第四次也是最后一次有效载荷分离事件原设计将在离轨燃烧后（这将使火箭的上面级处于在地球大气层中烧蚀殆尽的轨道上）发生。这两个有效载荷是小型再入舱，无法自行进行离轨燃烧，因此部署顺序不寻常。

在任务的两小时之前就很明显发现火箭的上级偏离了计划的轨道，未能提高其高度。欧空局直播评论员证实了这一偏差，理由是第二个辅助动力装置（APU）通电存在问题。

APU用于对火箭的上级油箱加压，以允许在轨芬奇发动机重新启动，确保燃料输送的一致性。此外，APU提供少量推力，有助于火箭在任务期间的机动性和精度。飞行两小时五十分钟后，欧空局结束了其任务直播，明确表示最后的离轨燃烧尚未成功完成。

部分内容来自Andrew Parsonson的报道

英文原文如下

During the inaugural flight of Europe’s Ariane 6 rocket, an anomaly occurred, resulting in two of the mission’s payloads not being deployed successfully.

The inaugural Ariane 6 mission was launched on 9 July at 21:00 CEST from the Guiana Space Centre. Just over one hour into the flight, three payload separation events were successfully performed over a period of just nine seconds. A fourth and final payload separation event was then expected to occur almost fours after liftoff following a deorbit burn that would put the rocket’s upper stage on a trajectory to burn up in Earth’s atmosphere. The two payloads were small re-entry capsules that could not perform their own deorbit burn, thus the unusual deployment sequence.

Just before a mission’s two-hour mark, it became clear that the rocket’s upper stage had deviated from its planned mission profile, failing to raise its altitude. The ESA broadcast commentators confirmed the deviation, citing an issue with the second Auxiliary Power Unit (APU) power-up.

The APU is used to pressurize the rocket’s upper stage tanks to allow for in-orbit Vinci engine restarts, ensuring consistent fuel delivery. Additionally, the APU provides a small amount of thrust, contributing to the maneuverability and precision of the rocket during its mission.

Two hours and fifty minutes into the flight, ESA concluded its mission broadcast with it clear that a final deorbit burn had not been succesfully completed.

During a post-launch press conference, ArianeGroup CEO Martin Sion revealed that the APU had initially powered up before abruptly stopping. Without the APU, the rocket was not able to restart its Vinci engine for a second time to complete a deorbit burn. Sion added that the stage’s passivation was triggered successfully. Passivation refers to the process of removing stored energy from a vehicle to reduce the risk of high-energy releases (explosions or fragmentations, for example) that could produce unwanted orbital debris.

In a November 2021 post, ArianeGroup stated that an example of APU’s versatility was “its ability to de-orbit the stage at the end of a mission in accordance with European space law by powering it towards Earth, so that it burns up on atmospheric entry.” Despite this, Sion did not appear to think that the failure to deorbit the mission’s upper stage was all that significant.

“What is clear is that there are a lot of upper stages that are still orbiting and take several years to go back, depending on the orbit. So it’s not a unique situation.” He went on to add, “This is something which does not create more hazard than what happens with the vast majority of launchers.”

Sion attempted to further downplay the impact of the anomaly, stating that it had occurred during a “demonstration phase” of the mission. According to the ArianeGroup CEO, this phase of the mission was intended to examine how the upper stage behaved in microgravity and how the different systems operate in this environment.

“This is why, from the beginning, we were very clear on the fact that there were two aspects. One was to demonstrate the launcher’s success, which we did. And then to understand and to and gather as much information as possible in this microgravity phase.”

While European Spaceflight can not confirm without a doubt that this differentiation was not made clear “from the beginning,” what is clear is that ESA’s official mission kit, which was published prior to the launch, does not distinguish between the two phases of the mission described by Sion. The mission’s “Launch Timeline” also does not outline different phases of the flight.

What’s next for Ariane 6?

According to ESA, data from different ground stations detailing how the upper stage performed will first need to be collated before an analysis of the data can begin. This process is expected to take a few days, and the subsequent analysis to determine what happened to the APU will take between one and two weeks.

Despite not yet understanding what happened to the APU during the inaugural flight, Arianespace CEO Stephane Israel confirmed that the investigation would have no impact on the rocket’s first operational launch, which is expected before the end of 2024.

“We are perfectly on track now to make the second launch this year,” said Israel. “It has no consequence on the next launches.”

This is likely partially true. ArianeGroup has proven that Ariane 6 can successfully complete a standard mission profile. This has allowed the company to move forward with the rocket’s next flight, which is expected to carry a French spy satellite to orbit. However, the rocket may continue to not be able to complete a deorbit burn until the problem with the APU can be fully understood.