NASA speeds moon communication to near real-time
- — 21 August, 2009 08:00
How often do you go to make a call on your cell phone and you're stymied by a bad connection?
Consider trying to make that call from ... well, the moon.
NASA engineers did when they were setting up the communications system that would send massive amounts of data from the Lunar Reconnaissance Orbiter across 238,000 miles back to Earth. Agency officials described the new system to reporters yesterday.
NASA's Lunar Reconnaissance Orbiter was launched from Cape Canaveral Air Force Station in Florida on June 18. A second satellite, the Lunar Crater Observation and Sensing Satellite, lifted off at the same time.
NASA scientists are hoping the two satellites can provide them with new information about the moon. NASA has been planning on putting humans back on the moon by 2020 but those plans are in flux giving the current economic conditions and the Obama administration's review of NASA's space missions.
NASA officials say that getting more information about moon will be key to any return there.
The Reconnaissance Orbiter is expected to orbit about 31 miles above the surface of the moon for the next year as part of an effort to map the moon's surface and find a good landing site for future NASA manned missions there.
The orbiter is designed to compile high-resolution 3-D maps of the moon's surface and survey it at many different spectral wavelengths.
According to NASA, the orbiter will amass more information about the moon's surface and environment than any previous mission.
The issue has been how to get all of that data back to scientists on Earth where it could do them some good.
To make that happen, NASA is depending on a 13-inch-long tube, called a Traveling Wave Tube Amplifier, which was built by L-3 Communications Electron Technologies.
It's designed to enable the orbiter to send massive amounts of images and data at an "unusually fast" rate to a receiver at a K-band antenna network at White Sands Test Facility in New Mexico. It's the first high-data rate K-band transmitter to fly on a NASA spacecraft, according to the space agency.
Because of the amplifier, the orbiter should be able to transmit 461 gigabytes of data per day, NASA noted, adding that it's more information than is generally found in a four-story library.
And it transmits the information at a rate of up to 100 megabytes per second, compared to a typical high-speed Internet service of about 1 to 3 megabytes per second.
"We're sending back more data than ever, and it's nearly real time," said project manager Todd Peterson in an interview today.
According to NASA, the device is a vacuum with electrodes inside that are geared to amplify microwave signals to high power.
It's a good set up for sending large amounts of data over a long distance because it provides more power and more efficiency than the traditional transistor amplifier, NASA noted.
NASA has used Traveling Wave Tube Amplifiers in other missions - notably with Kepler and Cassini - but they weren't as powerful. With the amplifier for the lunar orbiter, engineers redesigned the circuitry and built it by hand.