Neutron's first launch slips again amid trouble with carbon composites

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Rocket Lab announced Wednesday that its Neutron launch vehicle won’t fly until 2027, citing an issue discovered during manufacturing of the rocket’s carbon composite structures. The announcement was public confirmation of what nearly everyone inside Rocket Lab and the wider space industry already knew.

火箭实验室（Rocket Lab）周三宣布，其“中子”（Neutron）运载火箭要到2027年才能首飞，原因是该火箭在制造碳复合材料结构的过程中发现了问题。这一声明公开证实了火箭实验室内部及整个航天业几乎人尽皆知的事实。

The most recent official update from Rocket Lab in August suggested the company still held hope of delivering the first Neutron rocket to its launch pad at Wallops Island, Virginia, before the end of this year, a schedule that would have almost certainly pushed the first flight into 2027. But Rocket Lab’s statement Wednesday about Neutron’s schedule suggests the company is still struggling with manufacturing the rocket’s large booster stage.

火箭实验室在8月份发布的最新官方消息曾暗示，公司仍希望在今年年底前将首枚“中子”火箭运抵位于弗吉尼亚州瓦勒普斯岛的发射台，但这一时间表几乎肯定会将首飞推迟到2027年。然而，火箭实验室周三关于“中子”火箭进度的声明表明，该公司在制造火箭大型助推级方面仍面临困难。

Neutron’s reusable first stage is made of carbon composite structures, which offer low weight, high strength, and corrosion resistance. But carbon composites in aerospace are generally harder to manufacture than metallic structures. Peter Beck, Rocket Lab’s founder and CEO, identified a manufacturing defect as the reason for Neutron’s latest schedule slip.

“中子”火箭的可重复使用第一级由碳复合材料结构制成，具有重量轻、强度高和耐腐蚀的优点。但在航空航天领域，碳复合材料通常比金属结构更难制造。火箭实验室创始人兼首席执行官彼得·贝克（Peter Beck）将此次“中子”火箭进度推迟的原因归结为制造缺陷。

The problem lies in the dome sections at the ends of the rocket’s first stage propellant tanks. “Recently, we identified an issue with the manufacturing process for the propellant domes specifically, and this caused us to delay production and investigate further,” Beck said in a video released by Rocket Lab.

问题出在火箭第一级推进剂储箱两端的圆顶部分。贝克在火箭实验室发布的一段视频中表示：“最近，我们专门针对推进剂圆顶的制造工艺发现了一个问题，这导致我们不得不推迟生产并进行深入调查。”

Engineers discovered voids, or air pockets, between layers of carbon fiber that make up the domes’ composite structure. Carbon composite manufacturing involves laying down carbon fiber layers in a mold, then curing, or heating, the material to bind the fibers together. But this is a tricky process, especially for large structures that won’t fit into an autoclave, a high-pressure thermal curing chamber common in modern aerospace factories.

工程师在构成圆顶复合结构的碳纤维层之间发现了空隙（即气穴）。碳复合材料的制造过程包括将碳纤维层铺设在模具中，然后进行固化（即加热），使纤维结合在一起。但这道工序非常棘手，尤其是对于那些无法放入高压釜（现代航空航天工厂中常见的高压热固化室）的大型结构而言。

The Neutron rocket’s first stage is the “largest pressurized structure ever made out of carbon composite,” Beck said. “Because of its scale, we’ve had to develop new out-of-autoclave processes to build Neutron, and this includes custom cure cycles for the very large pieces, like the forward and aft domes for the propellant tanks on Stage One.”

贝克称，“中子”火箭的第一级是“有史以来用碳复合材料制造的最大压力结构”。他说：“由于其规模巨大，我们必须开发新的非高压釜工艺来制造‘中子’火箭，这包括为第一级推进剂储箱的前后圆顶等超大部件定制固化周期。”

Inspections revealed voids in a newly cured forward dome, defects that could affect the structure’s strength, durability, and reliability, Beck said. “They don’t necessarily mean that the dome would fail in flight, but our practice is to proceed only when we believe the system has the appropriate margins.”

贝克表示，检查发现新固化的前圆顶存在空隙，这些缺陷可能会影响结构的强度、耐用性和可靠性。“它们并不一定意味着圆顶会在飞行中失效，但我们的做法是，只有在我们认为系统具备适当余量时才会继续推进。”

Engineers traced the voids to a recent design change intended to strengthen the rocket’s structure. Rocket Lab introduced the design change after a Neutron propellant tank unexpectedly ruptured during a hydrostatic pressure test in January, a failure blamed on a manufacturing defect at a “critical join” in the tank.

工程师将这些空隙追溯到最近为加强火箭结构而进行的一项设计变更。火箭实验室是在今年1月“中子”火箭推进剂储箱在静水压力测试中意外破裂后引入该设计变更的，那次故障被归咎于储箱“关键连接处”的制造缺陷。

Officials said the failed carbon composite tank was manufactured by a “third-party contractor using a manual hand-lay process,” a decision made to allow tank testing to move forward while Rocket Lab brought online an automated fiber placement machine, which is now operational. Rocket Lab also deleted joints in the first stage tank structure and increased the thickness of some sections of the carbon composite. “Those thicker sections are where the voids formed,” Beck said.

官方表示，那个失效的碳复合材料储箱是由“第三方承包商使用手工铺层工艺”制造的，当时做出这一决定是为了在火箭实验室启用自动化纤维铺放设备（现已投入使用）的同时，让储箱测试能够继续进行。火箭实验室还取消了第一级储箱结构中的接头，并增加了部分碳复合材料的厚度。贝克说：“那些较厚的区域正是空隙形成的地方。”

Rocket Lab said the problem appears to be solved after modifying the manufacturing process again. An aft propellant dome made with the updated procedure passed inspection. “We’ve solved the problem,” Beck said. “That gives us complete confidence to move forward with the new forward dome. That process to make a new forward dome, combining with all the time that it took to investigate, identify, and resolve the issue, has pushed Neutron’s first launch date to next year.”

火箭实验室表示，在再次修改制造工艺后，问题似乎已得到解决。采用更新工艺制造的后推进剂圆顶已通过检查。贝克说：“我们已经解决了这个问题。这让我们有充分的信心继续推进新的前圆顶制造。制造新前圆顶的过程，加上调查、识别和解决问题所花费的时间，已经将‘中子’火箭的首飞日期推迟到了明年。”

The Neutron rocket is significantly larger than Rocket Lab’s Electron launch vehicle, also made of carbon fiber. The light-class Electron rocket is 3.9 feet (1.2 meters) in diameter, while the medium-lift Neutron measures 23 feet (7 meters) across at its widest.

“中子”火箭比火箭实验室同样采用碳纤维制造的“电子”（Electron）运载火箭大得多。轻型“电子”火箭直径为3.9英尺（1.2米），而中型运载火箭“中子”最宽处直径达23英尺（7米）。

Rocket Lab completed qualification testing on Neutron’s expendable second stage and payload fairing last year. The rocket’s design is unique: The upper stage and payload rest inside the first stage’s nose cone during the initial phases of launch. A few minutes after liftoff, Neutron’s booster stage will open its clamshell-like nose cone to release the upper stage and payload to continue accelerating into orbit. Then the first stage will close its payload fairing and return to landing on an offshore platform for reuse.

火箭实验室去年完成了“中子”火箭一次性第二级和有效载荷整流罩的鉴定测试。该火箭的设计非常独特：在发射初期，上面级和有效载荷位于第一级的鼻锥内。起飞几分钟后，“中子”助推级将打开其蛤壳状鼻锥，释放上面级和有效载荷，使其继续加速进入轨道。随后，第一级将关闭有效载荷整流罩，并返回海上平台着陆以实现重复使用。

Neutron’s first stage methane and liquid oxygen tanks are the largest elements of the rocket, and they must withstand internal pressure and the rigors of launch and reentry. Rocket Lab’s checklist for the first Neutron flight is long. Final qualification of the first stage is still pending, as is qualification of the rocket’s methane-fueled Archimedes engine, nine of which will power the Neutron booster.

“中子”火箭第一级的甲烷和液氧储箱是火箭最大的部件，它们必须承受内部压力以及发射和再入过程中的严苛考验。火箭实验室为“中子”火箭首飞准备的清单很长。第一级的最终鉴定尚未完成，火箭的甲烷动力“阿基米德”（Archimedes）发动机的鉴定工作也同样在进行中，该助推器将由九台此类发动机提供动力。

Rocket Lab reported in August that it was heading into the “final stretch” of engine qualification testing. Once that is complete, teams will begin the launch campaign on Virginia’s Eastern Shore. Launch campaigns for new rockets often take months before a first flight, involving multiple integrated fueling tests, countdown rehearsals, and a static fire. Engineers often discover new problems during integrated testing, requiring repeat tests and tweaks to procedures and hardware on the launch pad and the rocket. That is the purpose of such testing.

火箭实验室在8月份报告称，发动机鉴定测试已进入“最后冲刺阶段”。一旦完成，团队将开始在弗吉尼亚州东海岸进行发射活动。新火箭的发射活动通常在首飞前需要数月时间，涉及多次综合加注测试、倒计时演练和静态点火。工程师经常在综合测试中发现新问题，需要重复测试并对发射台和火箭上的程序及硬件进行调整。这正是此类测试的目的所在。

Rocket Lab announced the Neutron rocket in 2021, aiming for a first flight in 2024. The Neutron development timeline has now doubled. Beck said Wednesday.

火箭实验室于2021年宣布了“中子”火箭项目，目标是在2024年实现首飞。目前，“中子”火箭的开发周期已经翻了一番。贝克周三表示。