Voyager35 years after its departure from Earth, NASA’s Voyager 1 space probe registers major changes in its environment, including a large spike in radiation readings believed to indicate the presence of interstellar cosmic radiation. Some scientists claim that these changes in Voyager 1’s surroundings meet the expected criteria for space beyond the influence of Earth’s sun, making Voyager 1 the first man-made craft to reach interstellar space; others, including former Voyager project scientists, disagree with that assessment. Voyager 1 has no further planetary stops, and is expected to pass within two light years of the star Gliese 445 in 40,000 years.