内容来源：https://www.engadget.com/2193925/nasa-x-59-reaches-speed-and-altitude-milestones-ahead-of-first-quiet-supersonic-flights/

内容总结：

据美国国家航空航天局（NASA）最新消息，其研发的X-59静音超音速研究机已成功达到关键的速度与高度指标，为近期在美国社区上空进行首次低噪音超音速飞行奠定了基础。这款新型飞机旨在突破传统音障时仅产生“轻柔音爆”，而非震耳欲聋的轰鸣声。

在本月初实现首次超音速飞行后，X-59于上周五的测试中达到马赫数1.4（约每小时924英里），飞行高度攀升至5.5万英尺。此前6月5日的测试中，该机已实现马赫数1.1的飞行速度。NASA表示，此次测试“是比前次更为关键的里程碑”，因为其验证了即将开展的“静音超音速飞行任务”（Quesst）所需的飞行参数。

根据任务规划，未来数月内X-59将进入声学验证阶段，科研团队将精确测量其超音速飞行时产生的声学特征，确保该机在突破音障时不会产生传统音爆。此后，飞机将飞越美国人口稠密地区，收集地面民众对“轻柔音爆”的实际听觉反馈。目前测试期间，X-59需与另一架会产生传统音爆的研究机编队飞行，以掩盖自身测试噪音。

中文翻译：

美国国家航空航天局X-59试验机达到速度与高度里程碑，即将首次进行静音超音速飞行
该飞机很快将准备就绪，飞越美国城市社区。
NASA的X-59研究机本月初完成了首次超音速飞行，如今已证明它能够达到未来计划飞越美国社区所需的速度与高度条件。X-59的设计目标是在不产生巨大音爆的情况下实现超音速飞行——据NASA称，它只会发出“安静的沉闷音爆”。不过目前，它正与另一架会产生音爆的研究飞机编队飞行，以便在测试过程中掩盖自身发出的任何声响。
在周五的试飞中，X-59达到了1.4马赫（约合每小时924英里）的速度，并攀升至55000英尺的高度。而在6月5日的上一次飞行中，它达到了1.1马赫。
NASA表示，这次最新测试“是比前面测试更为关键的一步”，因为它达到了将在后续“静音超音速任务”中复现的关键目标。这项尚需数月才能进行的Quesst任务，将让X-59飞越人口稠密地区，以便NASA收集地面公众对所谓“沉闷音爆”听觉效果的反馈。不过在此之前，这架飞机还需经历声学验证阶段——团队将测量其超音速声学特征，确保它确实能在不产生传统音爆的情况下突破音障。

英文来源：

NASA's X-59 reaches speed and altitude milestones ahead of first quiet supersonic flights
The plane will soon be ready to fly over US communities.
NASA's X-59 research plane took its first supersonic flight at the beginning of the month, and now it's demonstrated that it can reach the speed and altitude conditions it'll need to achieve for planned trips over US communities in the near future. The X-59 is designed to fly at supersonic speeds without producing a loud sonic boom; instead, it'll make a "quiet sonic thump," according to NASA. For now, though, it's flying alongside another research craft that does produce a sonic boom, to obscure whatever noise it makes as it undergoes testing.
In a test flight on Friday, the X-59 flew Mach 1.4, or about 924 mph, and reached an altitude of 55,000 feet. For the previous flight, on June 5, it hit Mach 1.1.
The space agency says this latest test "was an even more critical step" than the one that preceded it, as it hit key targets that it'll replicate during its Quesst mission. The Quesst mission, which is still months away, will see the X-59 fly over populated areas so NASA can get feedback from the public on what the sonic thump sounded like to listeners on the ground. Before that, though, the plane will go through an acoustic validation phase, in which the team will measure its supersonic acoustic signature to make sure it is indeed breaking the sound barrier without producing a traditional sonic boom.