NASA’s Lunar Laser Communication Demonstration (LLCD) has made history using a pulsed laser beam to transmit data over the 239,000 miles between the moon and Earth at a record-breaking download rate of 622 megabits per second (Mbps).
LLCD is NASA’s first system for two-way communication using a laser instead of radio waves. It also has demonstrated an error-free data upload rate of 20 Mbps transmitted from the primary ground station in New Mexico to the spacecraft currently orbiting the moon.
“LLCD is the first step on our roadmap toward building the next generation of space communication capability,” said Badri Younes, NASA’s deputy associate administrator for space communications and navigation (SCaN) in Washington. “We are encouraged by the results of the demonstration to this point, and we are confident we are on the right path to introduce this new capability into operational service soon.”
Since NASA first ventured into space, it has relied on radio frequency (RF) communication. However, RF is reaching its limit as demand for more data capacity continues to increase. The development and deployment of laser communications will enable NASA to extend communication capabilities such as increased image resolution and 3-D video transmission from deep space.
“The goal of LLCD is to validate and build confidence in this technology so that future missions will consider using it,” said Don Cornwell, LLCD manager at NASA’s Goddard Space Flight Center in Greenbelt, Md. “This unique ability developed by the Massachusetts Institute of Technology’s Lincoln Laboratory has incredible application possibilities.”
LLCD is a short-duration experiment and the precursor to NASA’s long-duration demonstration, the Laser Communications Relay Demonstration (LCRD). LCRD is a part of the agency’s Technology Demonstration Missions Program, which is working to develop crosscutting technology capable of operating in the rigors of space. It is scheduled to launch in 2017.
LLCD is hosted aboard NASA’s Lunar Atmosphere and Dust Environment Explorer (LADEE), launched in September from NASA’s Wallops Flight Facility on Wallops Island, Va. LADEE is a 100-day robotic mission operated by the agency’s Ames Research Center at Moffett Field, Calif. LADEE’s mission is to provide data that will help NASA determine whether dust caused the mysterious glow astronauts observed on the lunar horizon during several Apollo missions. It also will explore the moon’s atmosphere. Ames designed, developed, built, integrated and tested LADEE, and manages overall operations of the spacecraft. NASA’s Science Mission Directorate in Washington funds the LADEE mission.
The LLCD system, flight terminal and primary ground terminal at NASA’s White Sands Test Facility in Las Cruces, N.M., were developed by the Lincoln Laboratory at MIT. The Table Mountain Optical Communications Technology Laboratory operated by NASA’s Jet Propulsion Laboratory in Pasadena, Calif., is participating in the demonstration. A third ground station operated by the European Space Agency on Tenerife in the Canary Islands also will be participating in the demonstration.
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At the Satish Dhawan Space Centre in Sriharikota, India this morning (Feb. 25), the smallest astronomical satellite ever built was launched into orbit aboard the Polar Satellite Launch Vehicle C20 rocket. In fact, it wasn’t just one satellite, but two – each of the twin BRIght Target Explorer (BRITE) spacecraft take the form of a cube that measures just 20 cm (7.8 inches) per side, and weighs in at under seven kilograms (15.4 lbs).
The BRITEs were designed at the Space Flight Laboratory (SFL) of the University of Toronto Institute for Aerospace Studies. One of the two nano-satellites launched today, known as UniBRITE, was assembled at SFL and funded by the University of Vienna. The other, called BRITE-Austria, was assembled in Austria and funded by that country’s Technical University of Graz – it is being promoted as “Austria’s First Satellite.”
Once in orbit, the satellites will work together to monitor changes in brightness of some of the largest, brightest stars in the sky. Their relatively small onboard telescopes limit their ability to monitor dimmer stars, or to take “pretty pictures.” Unlike ground-based telescopes that could be used to view those same stars, however, the satellites won’t be limited by scintillation – the visual distortion of celestial bodies, created by turbulence in the Earth’s atmosphere. They will also be able to image their target stars day and night, and won’t be thwarted by weather conditions such as cloud cover.
Because such large stars oscillate more slowly than smaller ones, the satellites won’t have to monitor them continuously. Instead, they can just check in on the stars at regular intervals, taking note of what changes in brightness have occurred. This, in turn, means that the satellites don’t need to be placed in one “right” orbit, where they can see their chosen star at all times. As a result, future BRITEs could hitch a ride into space on any available rocket, and placed into orbit wherever it was convenient – within reason.
Along with their telescopes, each of today’s two satellites contain three computers: one for instrument processing, one for housekeeping (keeping the satellite running), and one for attitude control. Approximately six watts of electrical power is provided by onboard solar cells.
Plans call for two other pairs of BRITE satellites to join the pair launched today, forming a “constellation” of six nano-satellites that will work together. Two of them will be Canadian, while two will be Austrian and two will be Polish.
“Big bright stars lead short and violent lives and deaths (supernovas) and in the process seed the universe with heavy elements without which life on Earth would be impossible,” the University of Toronto stated in a press release. “To better understand these stars is to better understand how life arose on our planet.”
More information on the construction of the nano-satellites is available in the video below.
A rocket carrying an Earth observation satellite is scheduled to blast off from the California coast on a mission to keep a continuous eye on the planet’s resources.
The countdown for the Atlas V launch begins Monday morning from the Vandenberg Air Force Base along California’s central coast. The Landsat satellite is the eighth of its kind to be launched since 1972 to track glaciers, forest fires, crop production and coastlines.
Unlike its predecessors, the latest carries more powerful sensors and can return more images.
For the past four decades, the polar-orbiting Landsat satellites have documented changes to Earth’s surface including the effects of deforestation and urban sprawl.
The $855 million mission is managed by NASA and the U.S. Geological Survey.