At more than 14 billion kilometers from the sun, Voyager 1 is farther from Earth than any other man-made object, yet the spacecraft is still within range of NASA's budget ax. The agency's new focus on human exploration--including the resumption of space shuttle flights scheduled for this month--is pulling funds from the unmanned spacecraft that study Earth, the sun and the outer reaches of the solar system.

In addition to devoting 40 percent of its $16.5-billion budget to the shuttle and the International Space Station, NASA has earmarked $753 million for the design of the Crew Exploration Vehicle, which will carry astronauts into orbit after the shuttle is retired in 2010. To help pay for this effort, the agency has proposed deep cuts to its Earth-Sun System Division, which operates Voyagers 1 and 2 and a dozen other probes that have completed their primary missions but are still yielding valuable data. Ordered to lop $20 million from the $75-million budget for the missions, the division will hold a review this fall to determine which spacecraft must be sacrificed. Potential victims include solar observatories (such as Ulysses and TRACE) as well as probes that investigate space weather around Earth (such as Polar, FAST, Geotail and Wind). To keep the craft running until the review, NASA has delayed funding research proposals to analyze the data from the missions.

The uproar over the Voyagers has been the loudest. Launched in 1977, the twin probes explored Jupiter, Saturn, Uranus and Neptune and can continue operating until they use up their plutonium fuel about 15 years from now. In 2002 Voyager 1 reported a surge in particle counts; the craft may have temporarily crossed the termination shock, the turbulent boundary where the solar wind begins to merge with the interstellar medium. The probe recently detected new signs of turbulence, and project scientists insist that canceling the $4.2-million-a-year program would be folly. Says Stamatios Krimigis, lead investigator for Voyager's low-energy particle detector: "It's like Columbus sighting land and then saying, 'Okay, let's go back.'"

Meteorologists and geologists are up in arms, too. In April a National Research Council (NRC) report declared that NASA's system of Earth-observing satellites "is at risk of collapse." Half a dozen missions have been canceled, downsized or delayed. In some cases, the cutbacks threaten to create gaps in environmental records that NASA has been compiling for decades. For example, the agency had originally intended to launch the Landsat Data Continuity Mission to succeed the aging Landsat 7 satellite, which tracks everything from deforestation in the tropics to collapsing ice sheets in Antarctica. But now NASA plans to build only the Landsat imagers and place them on weather satellites operated by the National Oceanic and Atmospheric Administration. The delay will almost certainly cause a data gap--Landsat 7, which was launched in 1999, is already faltering, and the first of the NOAA satellites will probably not go up until at least 2009. What is more, researchers warn that the NOAA satellites will be large and hence prone to vibrations, which may ruin the quality of the Landsat images.

The budget pressures are also slowing the effort to understand climate change. The future of the Glory mission, which would make the first global measurements of soot and dust to determine their impact on climate, is now uncertain; its instruments may be reassigned to one of the NOAA satellites. "Pushing all these things back is not okay," says Richard A. Anthes, a hurricane expert who co-chaired the NRC panel. "We can't afford not to observe Earth."

The scientific community is clearly hoping that NASA's new administrator, Mike Griffin, will reverse some of the cuts to research missions. Before taking the top job at NASA, Griffin headed the space department at Johns Hopkins University's Applied Physics Laboratory. Krimigis, who held the same position before Griffin, has faith in his colleague. "I know Griffin--I interviewed him for this job," Krimigis says. "I'm quite confident he'll do the right thing."