April 25, 1990: Hubble Space telescope launches into orbit
Although it may look like a giant tin can with wings, the Hubble Space Telescope is one of the cornerstone pieces of equipment in modern deep space exploration. Its high resolution, high magnification sensors have unveiled worlds billions of miles from our own. In partnership with other ground and space-based telescopes, Hubble has helped astronomers gain a better understanding of the universe around us.
An extraordinary piece of equipment
The Hubble Space Telescope was launched from the NASA site at Cape Canaveral on April 24, 1990. It piggybacked onboard the space shuttle Discovery up into low-Earth orbit, about 340 miles above sea level. From way up there, it takes the observatory just 95 minutes to travel around the globe. In spite of its speed, the telescope’s internal gyros keep it incredibly still when it is photographing distant star systems. Those gyros allow for no more than 7/1000ths of an arcsecond of wiggling, which is roughly the same as the width of a human hair when observed from a mile away.
Up in space, Hubble hurtles around the planet at a dizzying 17,000 miles per hour. While it is not the only space telescope orbiting Earth, it is the only one designed to be serviced while in orbit. Five service missions have been flown to Hubble, including one to replace its primary mirror. Space telescope mirrors require extremely precise, smooth shaping. The original mirror had a tiny imperfection in it that left circles on the photos, so the first service mission needed an astronaut to swap it out for a new one.
Since the bus-sized telescope took its first photo of the cosmos in 1990, it has provided a wealth of information to the scientific community. Over 1.3 million observations have been made by the observatory, and some 15,000 scientific papers have been written using that data. All of those scientific papers have been referenced hundreds of thousands of times in other research, making the Hubble Space Telescope one of the most productive individual scientific instruments ever built.