谷歌的轨道计算卫星原型今天搭乘一枚从加利福尼亚州发射的SpaceX火箭升空——这是这家科技巨头首次将自己的先进芯片送入太空。
Google’s prototype of its orbital compute satellite took off today onboard a SpaceX rocket launched from California — the first time the tech giant has sent one of its advanced chips into space.
这颗卫星由Planet Labs制造，将验证谷歌的张量处理单元（TPU）能否在太空中运行。TPU是英伟达GPU的竞争产品。这意味着必须持续提供1千瓦的电力、为芯片散热，并让一系列模型接受充分测试，以确定是否会出现问题。
Built by Planet Labs, the satellite will prove that a Google Tensor Processing Unit, its competitor to Nvidia’s GPUs, can function in space. That means supplying a kilowatt of continuous power, cooling the chip, and running a series of models through their paces to see if anything goes wrong.
“我们已经在地面进行了测试，但你知道，任何测试都无法完全代替真实运行。”负责谷歌“Suncatcher计划”的高管Travis Beals说。该计划旨在开发环绕地球运行的大规模计算集群。
“We’ve done testing on the ground, but you know, there’s no test that’s completely as good as the real thing,” said Travis Beals, the Google executive managing Project Suncatcher, the tech giant’s plan to develop large-scale compute clusters in orbit around the Earth.
投入运行后，这颗卫星每次启动TPU运行15分钟，以免给卫星的电力和热管理系统造成负担。这颗卫星基于Planet Labs打造的标准平台，但两家公司正在准备一项预计于明年实施的演示，届时将发射两颗更适合先进计算用途的卫星，能够承载运算量更大的工作负载。这些未来版本将尝试通过激光通信链路进行协同。
Once commissioned, the satellite will fire up its TPU in 15-minute bursts to avoid straining the satellite’s power and thermal management systems. This satellite is based on a standard platform built by Planet Labs, but the two companies are working on a demo expected to take flight next year that will see two satellites more purpose-built for advanced compute that can run more substantial workloads. Those future versions will attempt to collaborate via a laser communications link.
Suncatcher并不是这枚SpaceX火箭搭载的唯一太空AI载荷。该火箭将发射100多种不同载荷，其中包括来自Satlyt和Cowboy Space Company的任务。
Suncatcher isn’t the only space AI payload on this SpaceX rocket, which is launching more than 100 different payloads, including missions from Satlyt and Cowboy Space Company.
谷歌这项计划与这些初创公司（实际上也包括SpaceX本身）不同之处，在于它是一个长期项目。
What sets the Google initiative apart from those startups (and indeed from SpaceX itself) is that it’s a long-term project.
用Beals的话说，这项“长期登月计划”的重点，是为未来将出现的太空基础设施和AI工作负载进行建设。谷歌设想打造一个轨道数据中心：由81颗卫星组成近距离编队飞行网络，并行处理计算任务。
The focus of this “long-term moonshot,” as Beals puts it, is on building for the space infrastructure and AI workloads that will exist in the future. The company envisions an orbital data center that is a network of 81 satellites flying in close formation, processing in parallel.
“当你尝试运行跨多个机架的工作负载时，TPU之间的带宽和延迟确实至关重要……我们希望着眼未来，不仅考虑目前有哪些工作负载，还要考虑五年后会出现怎样的工作负载，”比尔斯说。很大程度上是因为，目前还不存在能够以经济可行的方式扩大轨道数据中心规模所需的火箭。
“The bandwidth and the latency between TPUs really, really matters when you’re trying to run a multi-rack workload…we’re trying to look ahead to not just what workloads exist today, but where they will be in five years,” Beals said. That’s largely because the rockets required to scale up orbital data centers in a cost-effective way don’t yet exist.
周四，谷歌还发布了其轨道数据中心白皮书的同行评审版本，这是目前关于算力如何进入轨道的最严谨分析之一。该论文将发表于《Joule》。
On Thursday, Google also released a peer-reviewed version of its white paper on orbital data centers, one of the most rigorous analyses available of how compute gets to orbit. The paper will be published in Joule.
论文最值得注意的方面之一，是谷歌如何看待进入太空这一问题。尽管研究人员强调，他们的分析并非经济可行性研究，但该分析呈现了一幅有趣的图景，让人得以了解谷歌如何看待未来火箭发射成本下降的趋势。
One of the paper’s most notable aspects is how Google thinks about access to space. Although the researchers stress their analysis isn’t an economic feasibility study, it offers an interesting picture of how the company sees rockets becoming cheaper over time.
与所有数据中心企业一样，谷歌正指望SpaceX将其航天器送入太空。（谷歌也是SpaceX的主要投资方。）作者认为，自“猎鹰1号”火箭发射以来，埃隆·马斯克的火箭团队已经实现了每年约20%的降价“学习曲线”，因此有理由预计，到2035年，SpaceX的发射价格将降至每公斤200美元左右。
Like all data center companies, Google is looking to SpaceX to get its spacecraft off the ground. (Google is also a major investor in SpaceX.) Arguing that Elon Musk’s rocket builders have achieved a price-reducing “learning curve” of about 20% a year since they launched the Falcon 1 rocket, the authors believe it’s reasonable to expect the company to deliver launch prices close to $200 per kilogram by 2035.
要实现这一目标需要什么？根据“猎鹰9号”运送的载荷量，研究人员认为，要让成本沿着类似轨迹下降，Starship需要将37万吨载荷送入轨道。这意味着未来10年需要大约1800次发射，即每年180次——而且这还要求每次任务都能运送200公吨载荷。
What will it take to do that? Based on the amount of payload launched by the Falcon 9, they think a similar cost-reduction trajectory will require Starship to fly 370,000 tons of payload into orbit. That’s something that would take it about 1,800 launches over the next 10 years, or 180 a year — and that’s if it can fly 200 metric tons on each mission.
对于一种一年内飞行次数从未超过5次的运载工具来说，这是一个巨大的要求。SpaceX预测，其发射频率将远高于这一数字。例如，埃隆·马斯克曾表示，Starship的发射频次到2029年可能达到这一水平，但马斯克可是什么话都敢说。
That’s a big ask for a vehicle that has never flown more than five times in a year. SpaceX predicts the company will be flying far more than that — Elon Musk has suggested Starship could achieve an flight rate in 2029, for example, but Musk says a lot of things.
至少从谷歌最新更新的研究来看，好消息是，其芯片似乎很可能能够承受太空辐射。公司发现测试配置中的芯片所获得的屏蔽比实际环境更强后，不得不在粒子加速器中重新对芯片进行高能粒子轰击测试。测试使芯片逻辑电路中出现了略多的错误，但公司仍有信心，其芯片能够在卫星五年的寿命期内于轨道上处理大规模推理工作负载。
The good news, at least, in Google’s updated research, is that it seems likely that its chips will survive the radiation of space. The company had to redo tests blasting the chips in a particle accelerator after they realized the configuration of the chips provided more shielding than they would actually experience. This produced slightly more errors in the chip’s logic circuitry, but the company is still confident its chips can handle large inference workloads in orbit for the five-year lifespan of a satellite.
“如果考虑的是典型推理操作，错误率非常低，对吧？比如百万分之一，”比尔斯说。“但另一方面，比如说，要进行某种超大规模训练，让数千枚芯片连续运行数月，那么这种错误率原本就会带来问题。”
“The error rate is very low if you’re thinking about typical inference operations, right? Like one in a million,” Beals said. “On the other hand, it was already problematic for doing, say, some mega-scale training run where you’re going to have many thousands of chips running for months.”