当今天的实况转播也不完美时,NASA怎么可能在1969年在全世界直播?How was it possible for NASA to live broadcast the moon landings worldwide in 1969 when we struggle with live broadcasts today?

【翻译自Quora, C Stuart Hardwick 的回答】

Simple. All they had to do was:

  • Pay Westinghouse and RCA a large sum of money to develop TV cameras small enough to fly aboard the spacecraft in an era when the typical studio camera weighed almost as much as a man and to operate within laughably tight power and bandwidth limitations. Westinghouse did this by using brand new technology, settling for a non-standard low frame rate and resolution, and taking certain technical shortcuts, some of which make the image quality less than what it might have been, but which contributed to the development of the home camcorder a few years later.
  • 在那个一般演播室的摄像机的重量几乎与人一样重,并且在可笑的功率和带宽限制下运行的时代,向Westinghouse和RCA支付巨款,以开发足够小到可以安置在飞船上的电视摄像机。Westinghouse采用了全新的技术,采用了非标准的低帧频和分辨率,并采用了某些技术捷径来实现此目的,其中一些捷径使图像质量不如以前,但这为几年后家用摄像机的发展做出了贡献。
  • Pay RCA a similarly large sum of money to develop transfer equipment capable of reading the non-standard signal (broadcast back to Earth as part of the spacecraft’s S-band data transmission, not on the TV band) and convert it to NTSC format for transmission to the networks. The conversion of one analog signal format to another using the technology of the time required the invention of a primitive forerunner of the DVR (which would lead to commercial instant replay a few years later) and the expedient of “filming” off a specially made high brightness TV screen using a standard studio camera.
  • 向RCA支付同样大笔的资金,以开发能够读取非标准信号的传输设备(作为航天器S波段数据传输的一部分广播回地球,而不是在电视波段)并将其转换为NTSC格式进行传输到网络。使用当时的技术将一种模拟信号格式转换为另一种信号格式,需要发明DVR的原始先驱(这将在几年后导致商业即时重播),并且需要“拍摄”特别制作的高使用标准演播室摄像机的亮度电视屏幕。
  • Pay a similarly large sum of money to set up or acquire transmission links back to Houston. Where today you’d just use the Internet and twenty years ago you’d lease a T1 line, NASA had to build the network from scratch.
  • 支付同样大笔的钱来建立或获取到休斯敦的传输链接。今天您只需要使用Internet,而20年前您要租用T1线路,NASA必须从头开始构建网络。
  • Pay many millions more to build or lease and equip the facilities of what is now called the Manned Spaceflight Network, using large parabolic dish antennas spaced around the world to provide continual coverage as the Earth turned and redundant coverage (which came in handy), with supplemental ARIA aircraft and ships to fill in gaps in coverage.
  • 花费数百万美元来建造或租赁并配备现在称为“载人航天”网络的设施,它使用在世界各地分布的大型抛物面碟形天线,以在地球旋转时也提供连续覆盖和冗余覆盖(派上用场),也使用ARIA飞机和轮船以填补覆盖范围的空白。
  • Plan the entire mission months in advance so that, by launching from Florida within a certain window, they would arrive at key mission objectives with the sun in a suitable position to see landmarks and targets clearly and without having the sun in their eyes, and then preplanning TV shots to avoid shooting into the sun and destroying the camera (though that happened once anyway) or shooting under lighting conditions beyond the range of the primitive camera.
  • 提前几个月计划整个任务,以便通过在特定窗口期从佛罗里达发射,这样当他们到目标时,太阳正处于合适的位置,可以清晰地看到地标和目标,而无需直视太阳,然后预先计划电视拍摄,以避免在阳光下拍摄和损坏相机(虽然无论如何都会发生)或在超出原始相机范围的光照条件下拍摄。
  • Invent large, collapsible parabolic S-band antennas that could be carried by the Service module and LM, and that could be deployed on the lunar surface for improved signal strength.
  • 发明大型,可折叠的抛物线形S波段天线,可以由服务模块和LM携带,并可以部署在月球表面以提高信号强度。
  • Plan time into the flight plan in which to test the TV equipment ahead of the landing. For example, during Apollo 11, about ten and a half hours after launch, right before the astronauts went to sleep, Houston asked them to shoot about ten minutes of basically anything just to exercise all the moving parts needed to get the signal back home and out to the networks.
  • 计划飞行计划中的时间,以便在着陆前测试电视设备。例如,在阿波罗11号发射后大约10个半小时内,就在宇航员睡觉之前,休斯顿要求他们拍摄大约10分钟的随便什么东西,只是为了激活所有必要不见以使信号返回地球进入网络。
  • Design and test a camera mount that would allow a camera mounted outside in a storage locker to be easily and reliably deployed by the first astronaut to step outside and then televise his progress down the ladder.
  • 设计和测试摄像头支架,该摄像头支架可以使第一位宇航员轻松而可靠地部署外部存储在储物柜中的摄像头,以便向外走动,然后将其前进过程通过梯子广播。
  • Design and test a pan/tilt head that would allow a camera mounted on a tripod (or later, a lunar rover) to be controlled remotely from Houston.
  • 设计和测试旋转云台,以使安装在三脚架(或后来的月球车)上的摄像机可以从休斯顿进行远程控制。
  • Plan, test, practice, execute.
  • 计划,测试,练习,执行。

In short, by planning every detail and paying a lot of money. Transmitting a signal from the moon to the Earth is not hard, there’s nothing to get in the way except Earth’s atmosphere. S-Band was used because it could penetrate the atmosphere, but getting the signal broadcast around the world was much harder than getting it back from the moon—of course, there was already some infrastructure in place for that.


Leave a Reply