PASADENA, Calif. - In this world of ever-accelerating everything, even the hustle of a 56-K modem on a home PC may seem pokey to those accustomed to higher-speed connections, like T-1 lines, at the office, making accessing the internet a sometimes agonizingly slow task.
Its a small consolation, but scientists connecting to spacecraft that probe Mars and other planets suffer the same frustration. They too, bite their nails and gnash their teeth as they watch data trickle in at interminably slow rates.
Take Mars Pathfinder, which set down on Mars with great fanfare on July 4, 1997. The spacecraft beamed back information from the Red Planet at an average rate of 300 bits per second, or about the equivalent of a paltry 30 megabytes of data each martian day.
"Its intolerable, but its our connection to Mars today," said Chad Edwards, of NASAs Jet Propulsion Laboratory, speaking Wednesday at the 46th annual meeting of the American Astronautical Society. "Its really an unacceptable level of connectivity and data return."
To remedy the situation, scientists are working at boosting the connections to spacecraft out roaming the far-flung reaches of the solar system. Key to that effort is increasing both bandwidth and the number of times a spacecraft can make contact with Earth each day.
By increasing the data rate to one megabyte per second, whole new worlds -- here scientists speak both figuratively and literally -- can be opened up for study. Even streaming video from the Martian surface would be possible.
"For long-range ground rovers, or aerobots hovering over the surface, that has all kinds of potential," Edwards said.
Bump the connection up to one gigabyte, and scientists can begin to study other planets in the virtual realm, creating for instance a computerized three-dimensional model of a martian rock that could be examined in real time. Thus, the planet could be brought to the geologist, rather than the geologist -- through his or her remotely operated instruments -- to the planet.
Complicating matters, however, is distance. Mars can be 250 million miles (400 million kilometers) from Earth. Round-trip travel time for beamed data can be 40 minutes.
That means probes like tiny aerobots or microprobes stuck in the Martian soil, simply could not transmit scientifically valuable data directly to Earth on their own.
"All of these are incapable, because of [limited] mass and power, to establish a direct link back to Earth," Edwards said.
Enter the answer: a low-cost constellation of highly sensitive communications satellites stationed in Mars orbit, relaying that data back to Earth.
NASA hopes to start launching by 2003 the first elements of what will become a six-piece swarm of low-orbit communications satellites to Mars, completing the series by 2009. A NASA budget for the Mars micro-missions could be completed in the next few weeks, said JPLs James Jordan during Wednesdays session.
The micro-sized satellites would be close enough to the surface to allow equally small instruments -- be they aerobots, airplanes, microprobes or balloons -- to communicate with them and, in turn, with Earth. Since their orbits would be varied as well, the Mars Network Micro-satellite Constellation Design would allow for more frequent contact with Earth.
Data would be returned faster, more frequently, with fewer blackout periods and with improved program resiliency, Edwards said. Lose one satellite -- as with what happened recently with the Mars Climate Orbiter -- and five others would be there to compensate for the loss.
And by 2007, NASA hopes to launch Marsat, a second-generation relay satellite that would park in orbit 10,500 miles (17,000 kilometers) above Mars and provide uninterrupted coverage of an entire martian hemisphere.
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