a standard established in the 1951 case Dennis v. U.S. whereby the government could suppress speech to avoid grave danger, even if the probability of the dangerous result was relatively remote; replaced by the imminent Lawless action (incitement) test in 1969.
Laika became the first living being to orbit the Earth on Sputnik 2, Nov. 3, 1957. She died several hours into the flight from stress and heat. On May 28, 1959, rhesus monkey Able and squirrel monkey Baker became the first to successfully return to Earth after space flight.
As a final test in preparation for a manned trip, a chimpanzee named Enos was launched into space in late November. The craft carrying Enos completed two orbits before landing safely back on earth, after which NASA announced that on December 20 of that year, John Glenn would make the first American orbital flight.