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[求助] 英译汉润色（航天通信相关）

英文原文：

NASA’s Evolution to Ka-Band Space Communications for Near-Earth Spacecraft

Over the next several years, NASA plans to launch multiple earth‐science missions which will send data from low-Earth orbits to ground stations at 1‐3 Gbps, to achieve data throughputs of 5‐40 terabits per day. These transmission rates exceed the capabilities of S-band and X‐band frequency allocations used for science probe downlinks in the past. Accordingly, NASA is exploring enhancements to its space communication capabilities to provide the Agency’s first Ka‐band architecture solution for next generation missions in the near‐earth regime. This paper describes the proposed Ka-band solution’s drivers and concept, constraints and analyses which shaped that concept, and expansibility for future needs.

For over five decades, NASA has launched and operated spacecraft for studying Earth and space phenomena. As both scientific knowledge and instrument technology have advanced during this period, the observation capabilities of these spacecraft have grown as well. The transmission rates and daily volumes of data collected by science probes orbiting the earth have correspondingly increased by several orders of magnitude. As the science data downlink rates have increased, so, too, have the signal bandwidths required to support these transmissions.

NASA, like all users of the radio spectrum, must respect frequency allocations established by the International Telecommunications Union (ITU). In ITU parlance, science data downlinks are designated as space-to-earth communications for the Earth Exploration Satellite Service or for the Space Research Service. The ITU has
allocated about 5 MHz for such purposes at S-band (approximately 2-4 GHz), 10 MHz for Space Science links and 375 MHz for Earth Science links at X-band (about 7-12 GHz), and 1.5 GHz for direct downlinks and 2.25 GHz space-to-space links at Ka-band (about 19-36 GHz). With growing bandwidths needed to support increasing data rates, downlink designs have evolved over the decades from S-band to X-band, and near-term future needs compel advancing further to Ka-band.

In advance of anticipated needs for Ka-band downlinks in the near-Earth region, NASA has developed a design for its networks operating in that region to support corresponding capabilities. This approach leverages three missions, presently under development, as references for understanding relevant needs and constraints for a solution enabling Ka-band near-Earth missions of the future.

我初步翻译的中文：

美国宇航局近地航天器的Ka波段空间通信的演变

在未来的几年中，美国宇航局计划发射多个地球科学航天任务，将以1-3 Gbps的速率从近地轨道发送数据到地面站，以达到每天5-40Tb的数据吞吐量。该传输速率超过了过去的科学探测器所使用S波段和X波段的下行能力。因此，美国宇航局正在探索增强其空间通信能力，以提供下一代近地任务的Ka波段通信架构的解决方案。本文介绍了提出的Ka波段解决方案的缘由和概念、约束，并分析概念的形成，以及对未来需求的可扩展性。

在过去的五十年中，美国宇航局已经发射和运转用于研究地球和空间现象的飞船。在此期间，科技和仪器工艺都有所进步，这些航天器的观测能力也得以增强。绕地科学探测器的传输速率和每日收集到的数据量也相应增加了几个数量级。随着科学数据下行速率的增加，需要一定的信号带宽，以支持这些数据的传输。

与所有其他无线电频谱的用户一样，美国宇航局必须遵循国际电信联盟（ITU）划分的频谱分配方案。国际电信联盟规定，科学数据下行被指定为用于地球探测卫星服务或空间研究服务的空-地通信。国际电信联盟（ITU）在S波段（约2-4 GHz）分配了约5 MHz用于空-地通信；在X波段（约7-12 GHz），分配了约10 MHz用于空间科学链接，约375 MHz用于地球科学链接；在Ka波段（约19-36 GHz），分配了约1.5 GHz用于直接下行，约2.25 GHz用于空-空链接。为支持更高的数据传输速率，通信带宽需求日益增长，近几十年，下行设计已从S波段发展到了X波段，在不久的将来，将迫使其进一步发展到Ka波段。

超过近地区域Ka波段下行的预期需求，美国宇航局已经制定了其在该区域的网络运作方案，以支持相应的功能。这种方法利用了三个任务，目前正在开发中，作为理解相关需求的参考，以及未来Ka波段近地任务解决方案的限制条件。

要求润色，谢谢！

[ 来自科研家族人工智能 ]

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