PASADENA, California -- And you think you have bandwidth problems?
You complain about excruciatingly slow Web servers and annoying connection failures from your ISP. Well, try communicating with a spacecraft hurtling through space millions of miles away -- spacecraft with the data transmission power of a refrigerator lightbulb.
That's what researchers at NASA's Deep Space Network deal with nearly every day, and their communications problems are only getting worse.
"There's just 24 hours in a day and only so many antennas," said John Watson, a spokesman at NASA's Jet Propulsion Laboratory. "Communications between the craft and mission control hasn't reached the critical point yet. But we want to be sure we don't reach the point of a meltdown."
The JPL's Deep Space Network is the key system for communicating with the spacecraft launched by many countries across the globe.
From antenna clusters on three continents -- near Goldstone, California; Canberra, Australia; and Madrid -- unmanned spacecraft can receive commands and transmit data to earthbound project managers.
Trouble is, there's not enough bandwidth, figuratively speaking, to go around. With more than 40 active missions a month vying for time on the network, the system is becoming increasingly overloaded.
High-profile missions such as the Mars Polar Lander, set to land 3 December, get immediate priority on the network, reducing the bandwidth available to other missions, Watson said.
The Deep Space Network receives and transmits signals from spacecraft roaming the far reaches of the solar system. Payload restrictions mean onboard communications equipment must be extremely compact and lightweight.
Very low power transmissions -- equivalent to a 20-watt bulb -- mean weak signals from missions that can command up to 18 hours per day on the network.
"It's becoming an increasing challenge," Watson said of the communications slot shortage. "People are trying to find creative ways to deal with it."
Part of the problem is that the network, built in the late 1950s and updated in the '80s, is ill equipped to handle the robust demands of space exploration, said Shirley Wolff, outreach coordinator for the Deep Space Network.
"[All of this expansion in space] means that there's more out there to communicate with," Wolff said.
The challenge has forced space missions to become ever-more efficient and selective about communications. "Space craft project managers are more judicious about how they decide what needs to be transmitted -- they're reducing the amount of repetitive data," said Douglas Griffith, the network's deputy manager of plans and commitments.
The strain on the network has also inspired JPL researchers to experiment with new technologies that could make spacecraft less dependent on standard communications.
"If we can make the crafts self-directing and autonomous, then it only needs to report back, letting us know that everything is OK," Watson said.
American space missions currently communicate using two frequencies: S-Band, which operates at 2 GHz, and X band, at 8 GHz.
"The higher the frequency, the more data you can get down here," Griffith said.
One solution might be the use of a higher frequency radio wave, called Ka-Band, which operates at 32 GHz, a frequency that would allow for the transmission of "four times as much data in one quarter of the time," Griffith said.
JPL is currently experimenting with Ka-Band data transmissions on the Mars Polar Lander and Cassini missions. But widespread use of the higher frequency is at least five years away, officials said.
Wolff said there are caveats that come with using higher frequencies for communications.
"It needs more accurate tracking and pointing. It's harder to use." But she said, "If Ka works, then you could get more missions in there."
Researchers are also considering using lightwaves to transmit data. In one recent test, data was successfully sent to a Japanese spacecraft using a light beam, Griffith said, "It'll be the next step after Ka-Band."
