ARLA/CLUSTER: Nasa faz testes em TVHD via LASER

[João Costa > CT1FBF]

 NASA beams 'Hello, World!' video from space via laser

NASA successfully beamed a high-definition video 260 miles from the
International Space Station to Earth Thursday using a new laser
communications instrument.

Transmission of "Hello, World!" as a video message was the first
175-megabit communication for the Optical Payload for Lasercomm
Science (OPALS), a technology demonstration that allows NASA to test
methods for communication with future spacecraft using higher
bandwidth than radio waves.

"The International Space Station is a test bed for a host of
technologies that are helping us increase our knowledge of how we
operate in space and enable us to explore even farther into the solar
system," said Sam Scimemi, International Space Station division
director at NASA Headquarters in Washington. "Using the space station
to investigate ways we can improve communication rates with spacecraft
beyond low-Earth orbit is another example of how the orbital complex
serves as a stepping stone to human deep space exploration."

Optical communication tools like OPALS use focused laser energy to
reach data rates between 10 and 1,000 times higher than current space
communications, which rely on radio portions of the electromagnetic
spectrum.

Because the space station orbits Earth at 17,500 mph, transmitting
data from the space station to Earth requires extremely precise
targeting.
The process can be equated to a person aiming a laser pointer at the
end of a human hair 30 feet away and keeping it there while walking.

To achieve this extreme precision during Thursday’s demonstration,
OPALS locked onto a laser beacon emitted by the Optical Communications
Telescope Laboratory ground station at the Table Mountain Observatory
in Wrightwood, California, and began to modulate the beam from its
2.5-watt, 1,550-nanometer laser to transmit the video. The entire
transmission lasted 148 seconds and reached a maximum data
transmission rate of 50 megabits per second. It took OPALS 3.5 seconds
to transmit each copy of the "Hello World!" video message, which would
have taken more than 10 minutes using traditional downlink methods.

"It's incredible to see this magnificent beam of light arriving from
our tiny payload on the space station," said Matt Abrahamson, OPALS
mission manager at NASA's Jet Propulsion Laboratory (JPL) in Pasadena,
California. "We look forward to experimenting with OPALS over the
coming months in hopes that our findings will lead to optical
communications capabilities for future deep space exploration
missions."

The OPALS Project Office is based at JPL, where the instrument was
built. OPALS arrived to the space station April 20 aboard SpaceX's
Dragon cargo spacecraft and is slated to run for a prime mission of 90
days.

View the "Hello, World!" video transmission and animation of the
transmission between OPALS and the ground station, at:
http://youtu.be/1efsA8PQmDA

For more information about OPALS, visit:
http://go.nasa.gov/10MMPDO

For more information about the International Space Station, visit:
http://www.nasa.gov/station