A do-it-yourself team of engineers trying to lasso an aged but operational NASA space probe may have run into an insurmountable obstacle: Tanks on the spacecraft that were once full of nitrogen gas, needed to fire the thrusters, appear to be empty.

Without thrusters, there is no way to push the 36-year-old spacecraft, the International Sun-Earth Explorer-3, or ISEE-3, onto a trajectory to be captured back in Earth orbit. Instead, ISEE-3, which is otherwise in working order, will just fly by.

“Odds are, there is nothing we can do,” Keith Cowing, a leader of the effort, said Wednesday.

ISEE-3, launched in 1978, was designed to measure the wind that blows from the sun and buffets the Earth’s magnetic field. Later, it was sent to fly through the tail of a comet. After those successes, a few final firings of its thrusters in 1986 put it on course to rendezvous back with Earth in August.

In the meantime, NASA retired the probe and dismantled the transmitters needed to talk to it.

This year, Mr. Cowing, the editor in chief of the website NASA Watch, and Dennis Wingo, an engineer and entrepreneur, embarked on an effort to re-establish contact and capture ISEE-3.