NASA prepares to launch 600Mbps space laser system to replace conventional radio links
NASA is preparing to launch the Lunar Laser Communications Demonstration (LLCD), a testbed that will use lasers to send and receive data between Earth and the Moon. This will be the first time that NASA uses lasers instead of conventional S-band radio waves to communicate with spacecraft, allowing for massive data rates of up to 600 megabits per second, while also consuming much less power and requiring much smaller antennae. Ultimately, shifting to laser-based communications will allow NASA to receive much more data from spacecraft, allowing them to be outfitted with high-res cameras and other modern sensors that generate more data than S-band links can support.
Optical communications, as opposed to radio frequency (RF) communications (or simply “radio”), are desirable for three key reasons: Massive bandwidth, higher security, and lower output power requirements. All of these traits derive from the frequency of optical and radio waves. While S-band signals are in the 2-4GHz range (similar to your GSM, LTE, or WiFi link), the laser light used by the LLCD (near-infrared in this case) is measured in hundreds of terahertz. As a result, the wavelength of S-band signals is around 10cm, while near-infrared has a wavelength of just 1000nm — or about 100,000 times shorter. Not only can you cram a lot more data into into the same physical space, but there’s also terahertz (compared to megahertz in the S band) of free, unlicensed space that can be used.
NASA is preparing to launch the Lunar Laser Communications Demonstration (LLCD), a testbed that will use lasers to send and receive data between Earth and the Moon. This will be the first time that NASA uses lasers instead of conventional S-band radio waves to communicate with spacecraft, allowing for massive data rates of up to 600 megabits per second, while also consuming much less power and requiring much smaller antennae. Ultimately, shifting to laser-based communications will allow NASA to receive much more data from spacecraft, allowing them to be outfitted with high-res cameras and other modern sensors that generate more data than S-band links can support.
Optical communications, as opposed to radio frequency (RF) communications (or simply “radio”), are desirable for three key reasons: Massive bandwidth, higher security, and lower output power requirements. All of these traits derive from the frequency of optical and radio waves. While S-band signals are in the 2-4GHz range (similar to your GSM, LTE, or WiFi link), the laser light used by the LLCD (near-infrared in this case) is measured in hundreds of terahertz. As a result, the wavelength of S-band signals is around 10cm, while near-infrared has a wavelength of just 1000nm — or about 100,000 times shorter. Not only can you cram a lot more data into into the same physical space, but there’s also terahertz (compared to megahertz in the S band) of free, unlicensed space that can be used.
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