NEPTUNE's ambition is emboldening others. Thanks to NEPTUNE, the proposed Japanese and European observatories should benefit from answers to several open questions that are contributing to the U.S. funding delay. How much will cabled observatories cost to operate? What unintended consequences may arise? And how quickly will scientists shift their approach to their work to take advantage of cabled observatories?

The cost of operation, of course, includes maintaining and replacing science instruments. Marcia McNutt, president and CEO of the Monterey Bay Aquarium Research Institute, says she is confident that NEPTUNE's infrastructure will last 30 years but says the scientific packages plugged into it may be another story. "We don't know how long the instruments are going to last, how much servicing they are going to need, or what that servicing will cost. That's a very legitimate concern," she says. The VENUS hydrophone array is a case in point. Its inventors hope it will last five years, but contractually the hydrophone is guaranteed to operate for just one year.

In the category of unintended consequences are tensions between NEPTUNE and VENUS management and the Canadian and U.S. navies. What concerns the militaries is the possibility that their foes will employ publicly available data from the systems' sophisticated hydrophones to identify vessels and track their comings and goings. (Canada's entire Pacific fleet docks at Vancouver Island, just west of Victoria, while a group of U.S. nuclear submarines calls nearby Puget Sound, Wash., home.)

The VENUS organizers granted the Canadian military the power to squelch VENUS's acoustic data whenever the navy deems national security to be at risk. That worries some NEPTUNE researchers. "For observatories expecting to have a 24/7 feed, that could be very disruptive to the science," says Benoît Pirenne, the assistant director of information technology for NEPTUNE Canada, who is designing NEPTUNE's data and control system.

Then there is the question of how, and whether, scientists will use cabled observatories. Pirenne, who previously handled data management for the Hubbell Space Telescope, says oceanographers will have to feel their way through the same transition that astronomers experienced several decades ago in learning how to use data mining to exploit remote and online research facilities. "It's going to be hard. Even the visionaries, the people who are very close to NEPTUNE, are still thinking in terms of real-time, hands-on experiments. They're talking about controlling cameras with a joystick," says Pirenne. "That's over. It's time for people to put together powerful algorithms that will pore through the data."

Many of NEPTUNE's proponents, such as Barnes and McNutt, see this change in thinking as the biggest hurdle facing ocean observatories such as NEPTUNE. McNutt says it has been a struggle trying to engage oceanography's leaders, scientists who have profited under the old way of doing things. "It's not going to be the boon for the leaders in the field who are already very comfortable with yesterday's technology," she says. Rather, she believes, NEPTUNE is for tomorrow's oceanographers: "It's for the visionaries who are not set in their ways, for the young people who will see ways to use it that we can't even imagine."