Katalyst’s satellite rescue mission is now in pursuit of NASA’s Swift

Katalyst 的卫星救援任务现已开启，目标直指 NASA 的“雨燕”卫星

High above the remote Pacific Ocean, about halfway between Hawaii and the northernmost part of Australia, an air-launched rocket fired into space on Independence Day weekend to kick off a weekslong pursuit of a NASA astronomy satellite perilously close to falling out of orbit. 在遥远的太平洋上空，位于夏威夷和澳大利亚最北端之间，一枚空射火箭在独立日周末发射升空，开启了为期数周的追逐任务，目标是一颗正处于坠落轨道边缘的 NASA 天文卫星。

The endeavor to rescue NASA’s Swift satellite is the first mission of its kind. NASA put out a call for commercial companies less than a year ago to propose how they could rapidly build and launch a small satellite to latch onto the Swift spacecraft and boost its altitude so that it doesn’t come down in a few months. 此次营救 NASA“雨燕”（Swift）卫星的行动是同类任务中的首例。不到一年前，NASA 向商业公司发出征集令，寻求能够快速制造并发射一颗小型卫星的方案，以便与“雨燕”号对接并提升其轨道高度，防止其在几个月内坠毁。

Katalyst Space Technologies responded with the best offer. NASA awarded the company a contract last September to build and launch a mission to rescue Swift. A little more than nine months later, Katalyst’s nearly half-ton Link satellite is safely in orbit. For anyone who follows the space industry, building, testing, and launching a functioning first-of-its-kind satellite of that size in less than a year is a remarkable achievement; it would usually take several years. Katalyst Space Technologies 凭借最优方案中标。去年 9 月，NASA 与该公司签署合同，委托其建造并执行此次救援任务。仅仅九个多月后，Katalyst 重约半吨的“链路”（Link）卫星已安全进入轨道。对于关注航天业的人来说，在不到一年时间内完成这种首创性卫星的制造、测试和发射是一项了不起的成就，因为这通常需要数年时间。

Getting to Swift

奔向“雨燕”

Technicians buttoned up the Link satellite inside the nose cone of a Northrop Grumman Pegasus XL rocket last month at NASA’s Wallops Flight Facility in Virginia. An aircrew flew the rocket and its L-1011 carrier aircraft from Virginia to the US Army’s Ronald Reagan Space and Missile Test Range on Kwajalein Atoll, a facility leased from the Marshall Islands more than 2,000 miles southwest of Honolulu. 上个月，技术人员在弗吉尼亚州的 NASA 瓦勒普斯飞行设施（Wallops Flight Facility）将“链路”卫星封装在诺斯罗普·格鲁曼公司“飞马座 XL”（Pegasus XL）火箭的整流罩内。机组人员随后驾驶载机 L-1011 将火箭从弗吉尼亚运往位于夸贾林环礁的美国陆军罗纳德·里根弹道导弹防御试验场，该设施位于檀香山西南 2000 多英里处，是从马绍尔群岛租借的。

Once there, the rocket and the L-1011 waited several days for good weather, then took off to fly to a predetermined launch zone south of Kwajalein. With everything in order and upon reaching a cruising altitude of 41,000 feet, the pilots released the 58-foot-long (18-meter) rocket at 4:36 am EDT (08:36 UTC) Friday. Five seconds later, the Pegasus XL ignited its solid-fueled first stage to begin the climb to orbit. 抵达后，火箭和 L-1011 载机等待了几天以避开恶劣天气，随后起飞前往夸贾林以南的预定发射区。一切准备就绪后，当飞机达到 41,000 英尺的巡航高度时，飞行员于周五凌晨 4:36（协调世界时 08:36）释放了这枚 58 英尺（18 米）长的火箭。五秒钟后，“飞马座 XL”点燃了固体燃料一级发动机，开始向轨道爬升。

It took just shy of eight minutes for the Pegasus XL’s three solid-fueled motors to accelerate to orbital velocity. The rocket’s upper stage completed a preprogrammed sequence to deploy the Link satellite nearly 13 minutes after launch. NASA confirmed later Friday that ground teams from Katalyst established communications with the Link satellite, confirming the spacecraft survived the ride on Pegasus. “飞马座 XL”的三级固体燃料发动机仅用了不到八分钟就加速到了轨道速度。火箭上面级完成了预设程序，在发射后近 13 分钟部署了“链路”卫星。NASA 在周五晚些时候确认，Katalyst 的地面团队已与“链路”卫星建立了通信，证实该航天器在“飞马座”的运载过程中完好无损。

Katalyst selected the rarely used Pegasus rocket, which has flown just once in the last seven years, because the Swift rescue mission needed to launch into an unusually low-inclination orbit to reach its target. Swift’s orbit is inclined 20.6 degrees to the equator, and the Link satellite would have required a launch on an oversized, more expensive rocket to reach that orbit from a spaceport like Cape Canaveral, Florida. Launching from the equatorial Pacific solved that problem. Katalyst 选择使用罕见的“飞马座”火箭（过去七年仅飞行过一次），是因为“雨燕”救援任务需要进入一个异常低倾角的轨道才能到达目标。“雨燕”的轨道与赤道倾角为 20.6 度，如果从佛罗里达州卡纳维拉尔角等航天发射场出发，则需要使用更大、更昂贵的火箭才能进入该轨道。而在赤道太平洋发射则解决了这一难题。

There are more trials ahead for Katalyst. The Swift rescue mission is the first time the company has flown this version of its Link satellite. In addition to the standard satellite systems required to generate power, maintain attitude control, and communicate with the ground, the Link spacecraft has cameras and sensors to guide itself toward Swift and three robotic arms to grab onto the observatory. Three plasma thrusters will propel Link and Swift to a higher orbit once Katalyst confirms a firm connection. Katalyst 前方还有更多考验。“雨燕”救援任务是该公司首次飞行此版本的“链路”卫星。除了发电、姿态控制和地面通信所需的标准卫星系统外，“链路”航天器还配备了用于引导其靠近“雨燕”的摄像头和传感器，以及用于抓取观测台的三只机械臂。一旦 Katalyst 确认连接稳固，三台等离子推进器将推动“链路”和“雨燕”进入更高轨道。

“Over the next several weeks, Katalyst will perform checkout procedures for Link, including assessments of its propulsion, sensor, and navigation systems,” NASA said in a statement. “Link will then approach Swift and complete a survey of the 21-year-old observatory, before capturing and lifting it over the course of several months.” NASA 在一份声明中表示：“在接下来的几周内，Katalyst 将对‘链路’卫星进行检查程序，包括对其推进、传感器和导航系统的评估。随后，‘链路’将靠近‘雨燕’，对这台已服役 21 年的观测台进行勘测，并在几个月的时间内完成抓取和提升任务。”

But Swift was never designed to meet up with another spacecraft in orbit. Engineers are unsure of the condition of Swift’s thermal insulation, and ground controllers will take a cautious approach to determining where and when Link’s robotic arms can capture the satellite. Officials from NASA and Katalyst acknowledge the unknowns. 然而，“雨燕”在设计之初并未考虑在轨道上与其他航天器对接。工程师们不确定“雨燕”热绝缘层的状况，地面控制人员将采取谨慎态度，以确定“链路”的机械臂在何处、何时可以抓取该卫星。NASA 和 Katalyst 的官员都承认存在诸多未知数。

“All this is challenging and risky,” said Kieran Wilson, principal investigator for the Link satellite at Katalyst. “There’s a lot of spacecraft that have had far longer development cycles with far more funding behind them that have failed for mundane reasons.” “这一切都充满挑战和风险，”Katalyst“链路”卫星首席研究员基兰·威尔逊（Kieran Wilson）表示，“许多开发周期更长、资金更雄厚的航天器，往往因为一些琐碎的原因而失败。”

But getting Link launched successfully is an accomplishment in and of itself, NASA officials said. Managers faced a real deadline. Based on current trends, Swift will fall below an altitude of 300 kilometers (186 miles) in October, when its orbit will be too low for Link to have a decent shot at completing the rendezvous due to increasing atmospheric drag. 但 NASA 官员表示，成功发射“链路”本身就是一项成就。管理人员面临着真正的最后期限。根据目前的趋势，“雨燕”将在 10 月份降至 300 公里（186 英里）以下的高度，届时由于大气阻力增加，轨道将过低，导致“链路”无法顺利完成对接。

“One thing that we’re relying on for Swift is its ability to maintain its own pointing control,” Wilson said. “There are no features on Swift that are designed to capture. There’s a lack of documentation to even help us figure out where those features would be if they existed, but we are confident that Swift can point well. Once we get to within tens of meters, Swift will be performing maneuvers in tandem with us in order for us to inspect the capture locations, ensure that they are free of torn-off MLI (Multi-Layer Insulation), whatever may be there, and to essentially move through various capture locations that we have.” “我们对‘雨燕’的依赖之一是它保持自身指向控制的能力，”威尔逊说，“‘雨燕’上没有任何专为抓取而设计的结构。我们甚至缺乏文档来帮助我们确定这些结构（如果存在的话）在哪里，但我们相信‘雨燕’的指向能力很好。一旦我们靠近到几十米范围内，‘雨燕’将与我们协同进行机动，以便我们检查抓取位置，确保它们没有脱落的多层隔热材料（MLI）或其他杂物，并基本上在我们预定的各个抓取点之间移动。”

NASA has a clear interest in saving the Swift mission. The $500 million observatory’s primary mission is detecting gamma-ray bursts, the most powerful explosions in the known Universe. Despite its age, astrophysicists still rely on Swift’s multi-wavelength instruments to identify and locate gamma-ray bursts for follow-up observations by other observatories. But part of the reason for launching a rescue mission to Swift is simply to see if it can be done. NASA 显然有动力拯救“雨燕”任务。这台耗资 5 亿美元的观测台的主要任务是探测伽马射线暴——已知宇宙中最强大的爆炸。尽管年事已高，天体物理学家仍依赖“雨燕”的多波段仪器来识别和定位伽马射线暴，以便其他天文台进行后续观测。但发起此次救援任务的部分原因，仅仅是为了验证这种操作是否可行。