The test during which Blue Origin’s rocket—a vehicle that, at 98 meters tall, is one of the largest ever built—exploded is known as a hotfire test, or static fire test. Essentially, it is a standard procedure carried out on the engines of a rocket, spacecraft, or prototype, in which the engines are ignited for a very short period of time and then shut down while the vehicle remains secured to the launch pad. The purpose of this test is to verify that the systems are functioning correctly before an actual launch.