Prior to the Apollo 11 mission in July 1969, NASA lacked a reliable way to transmit space-generated data to Earth. Still, everyone who was alive at the time probably remembers the footage of Neil Armstrong stepping out of the lander and giving his famous One Small Step for Man speech. This was possible because NASA set up both a dedicated communications network and a new broadcast standard to make sure it could bridge the 238,000-mile gap between Earth and the moon for millions of people.
The network itself consisted of evenly spaced antenna structures positioned around the world—one in California’s Mojave Desert, one in Spain, and two in Australia—so that one of them always faced the moon as the Earth rotated. But even then, bandwidth was a big deal because the network could only support very limited data streams in the 4.5 MHz broadcast spectrum, and most of that was clogged with data being sent from the lunar lander and spacecraft. ‘orbiter, with not enough left over for the finished video. NASA compensated by changing the video signal from the standard 525 scan lines at 30 frames per second, which was the standard for televisions at the time, to a much smaller format that was only 320 scan lines and 10 frames per second. .
This created a low resolution video, but millions of people watching around the world don’t seem to care. NASA has since restored and enhanced that original footage so that it’s now viewable in slightly better detail, though it comes next to nowhere near the HD quality of today’s photos and videos.
High quality photos and videos are one of the biggest challenges for the Deep Space Network, which is what NASA now calls that system of antenna complexes. The original radio wave antennas used for lunar missions still exist and have been supplemented by smaller and larger antennas to increase bandwidth. And with all the space missions going on, the network is extremely busy these days, which anyone can see on a special website that supports real-time monitoring.
While writing this article, I saw one of the US-based antennas suddenly activate and begin communicating with the Mars Odyssey Orbiter, currently located 312 million kilometers from Earth. That round-trip signal took 34 minutes. Meanwhile, another antenna activated and began receiving data from the James Webb Space Telescope, located just 1.72 million kilometers from Earth, which enabled a rapid 11.4-second round trip. . Elsewhere, in Madrid, one of the antennas was constantly communicating with the Korea Pathfinder Lunar Orbiter, receiving data from 371,000 kilometers away. And the Deep Space Network is always busy. I’ve never seen a time when the antennas were down.
And no wonder why, despite the new antennas, there is never enough bandwidth. Consider the aforementioned James Webb Telescope. It can generate gigabytes of data every single day, yet it has to retransmit it all back to the ground at about 25 Mbps. Some of the other spacecraft, which are much further away, have even slower bandwidth speeds available. For example, I’ve seen NASA’s Wind spacecraft transmitting for over an hour at just 73 kilobytes per second. And poor Voyager 1, adrift 23.8 billion kilometers from Earth, had to transmit its data at an average of only 100 bits per second.
Until recently, NASA didn’t have a good solution for building extra bandwidth into the Deep Space Network. Building more antennas helped, but only so much. In 2017, NASA began experimenting with laser communication systems, which seemed like a perfect replacement technology for radio waves since there’s not much to get in the way or interfere with lasers in space.
And one part of that program, the TeraByte InfraRed Delivery or TBIRD system, has just achieved staggering success, transmitting experimental space-originated data to Earth aboard the orbiting Pathfinder Technology Demonstrator 3 Cube satellite using a 200-gigabit per second. At those speeds, some of the aforementioned Deep Space Network transmissions that took hours to complete could have finished in less than a minute, with some of them taking less than a second.
This capability will change the way we communicate in space, said Beth Keer, mission manager for TBIRD at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. She only imagines the power of space science tools when they can be designed to take full advantage of advances in detector speeds and sensitivities, furthering what artificial intelligence can do with massive amounts of data. Laser communications are the missing link that will enable the scientific discoveries of the future.
It is becoming unreasonable to try to transmit critical data from space collected by modern equipment, cameras and eventually human explorers, using technologies such as the radio employed for space missions in the 1960s. Instead, the TBIRD system’s infrared lasers may offer a better path, especially if the technology continues to improve, and they can hit the jackpot with an even greater stream of data from even farther out into deep space.
John Breeden II is an award-winning journalist and reviewer with over 20 years of experience in the technology field. He is the CEO of the Tech Writers Office, a group that creates technology thought leadership content for organizations of all sizes. Twitter: @LabGuys
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