August 29, 2013
NASA Looks To Lasers For Deep Space Communications
Brett Smith for redOrbit.com - Your Universe Online
Laser-based fiber optic technology may slowly be becoming the standard way to send digital communications here on Earth – but for deep-space transmissions, NASA and other space agencies have been relying on radio waves to send data and computer codes.
That is expected to change when NASA initiates its Lunar Laser Communication Demonstration (LLCD) aboard the Lunar Atmosphere and Dust Environment Explorer (LADEE) mission. The demonstration will attempt to prove that two-way laser communication can expand the possibilities of data transmission. If successful, the technology could eventually be used to allow for 3D High Definition video transmissions deep into space.
“The goal of the LLCD experiment is to validate and build confidence in this technology so that future missions will consider using it,” said Don Cornwell, LLCD manager. “This unique ability developed by MIT, has incredible application possibilities and we are very excited to get this instrument off the ground.”
Since NASA’s very first mission, the space agency has used radio frequency (RF) communication as its primary platform. However, the technology is reaching its capacity as NASA transmissions become more and more data intensive.
“LLCD is designed to send six times more data from the moon using a smaller transmitter with 25 percent less power as compared to the equivalent state-of-the-art radio (RF) system,” said Cornwell. “Lasers are also more secure and less susceptible to interference and jamming.”
The demonstration is scheduled to be performed aboard LADEE, a 100-day unmanned mission that will launch in September and travel to the moon. It will attempt to determine if dust is the reason behind the mysterious glow on the lunar horizon seen by Apollo astronauts. LADEE will also explore the moon’s fragile, unusual atmosphere. The upcoming mission will also mark the maiden voyage of a Minotaur V rocket – a converted, excess ballistic missile.
After being launched, the LADEE spacecraft will take 30 days to arrive in lunar orbit and begin transmitting data. During the next 30days, the LLCD is tasked with transmitting hundreds of millions of bits of data per second back to Earth from lunar orbit – the equivalent of simultaneously transmitting over 100 HD television channels. NASA operators will also test the receiving capability of the LLCD using tens of millions of bits per second sent from Earth to the spacecraft.
NASA engineers said the laser system has even more advantages for communications outside Earth’s orbit. NASA has already experimented with sending short, individual optical pulses to distant probes near Jupiter, Mars, and Mercury. As well, an image of the Mona Lisa was recently transmitted to NASA’s Lunar Reconnaissance Orbiter (LRO), which is currently orbiting the moon.
“But this was done at only hundreds of data bits per second,” said Cornwell. “LLCD will be the first dedicated optical communication system and will send data millions of times faster.”
Cornwell added that the space agency plans to utilize the new system extensively in the future.
“We can even envision such a laser-based system enabling a robotic mission to an asteroid,” he said. “It could have 3-D, high-definition video signals transmitted to Earth providing essentially ‘telepresence’ to a human controller on the ground.”