ISS To Earth: Hello World Sent Via Laser
NASA has reached another milestone, and probably a world record, in its efforts to speed up communication between a spacecraft and Earth. It has just sent a short high-definition video from the International Space Station 260 miles above the planet to its ground base in California, using a laser beam instead of the traditional radio wave.
This accomplishment might sound rather mundane in light of science fiction, but it is really a world's first. NASA calls it the first 175 megabit message to be beamed down from space to earth using its fancy new Optical Payload for Lasercomm Science or OPALS. OPALS, as well as other laser-based communication technologies, employ the use of lasers in order to reach data transfer speeds 10 to 1,000 times faster than current radio wave-based processes. To put it into context, it took OPALS only 3.5 seconds to transmit the video, while it would normally take 10 minutes with conventional methods.
Transmitting via laser is no easy task either given how both sender and receiver are in motion. And not just any motion, but a fast one. The ISS orbits the earth at a speed of 17,500 mph. This is akin to trying to target a single strand of a person's hair 30 feet away, while walking at the same time. NASA managed to perform this feat by first emitting a laser beacon from the Table Mountain Observatory in Wrightwood, California. Once the ISS OPALS locked onto this beacon, it began to modulate the laser beam using its 2.5-watt 1,550-nanometer laser.
The video, which is shared by NASA below, lasts less than a minute. Entitled "Hello World", it is a throwback to the conventional first printed output used in programming lessons and tutorials. The video itself might seem unremarkable until you consider the technology, not to mention the resources, that was used to receive it in the first place from high up above the clouds.
Naturally, OPALS is being developed with an eye towards future deep space communications, where the delay from radio waves will be too costly. Laser is the next technology for such data transfers and the International Space Station, which was quite ironically considered for decommissioning recently, is the perfect testbed for such experiments.
SOURCE: NASA