How many shuttles

More than 30 years later, when Space Shuttle Atlantis rolled to a stop on the runway July 21, , the shuttle program officially came to a close. First conceived during the heady and well-funded time around the initial Moon landings, the Space Shuttle was intended to provide NASA with a low-cost means to bring humans and payloads to low-Earth orbit.

All these potential benefits of the shuttle were piled on top of one key promise: rapid turnaround of the spacecraft between flights. Some NASA personnel even anticipated that a shuttle would be able to carry out back-to-back flights within just a week or two.

Many of the predictions for the Space Shuttle came true: the fleet helped build the ISS, docked with the Mir space station , made extensive use of Spacelab, and carried many important payloads to orbit — including the Hubble Space Telescope , the Chandra X-ray Observatory , and interplanetary probes Magellan , Ulysses , and Galileo , among others.

By any yardstick, NASA can be proud of these accomplishments. First — and perhaps most importantly — the program was wildly expensive. While the shuttle was proposed to make disposable rockets a thing of the past, it did exactly the opposite. Most customers who wanted to put satellites into orbit found conventional rockets to be a cheaper alternative. Second, the proposed launch schedules and turnaround times for the shuttle fleet were essentially fantasy.

The fastest turnaround for any shuttle in the history of the program was 54 days. And after the Challenger disaster, the fastest turnaround was 88 days — a far cry from what NASA officials thought they could accomplish.

Slower turnarounds meant fewer flights, which meant less access to space for paying customers, further driving business away from NASA. Safety was also an issue of paramount importance for the Space Shuttle Program. By the mids, much of the American public thought that spaceflight was routine. NASA was even launching astronauts into space wearing just simple coveralls and helmets, having ditched the pressure suits used in the Mercury , Gemini , and Apollo programs.

This forever dispelled the notion that spaceflight was routine. The shuttle was revealed to be a high-risk, experimental vehicle — something most astronauts had known all along. Still, the space agency took its lashings and made the changes required to get the shuttle flying again. Yet again, the entire crew — this time featuring the highly publicized first Israeli astronaut, Ilan Ramon — was killed. Although the technical cause of the Columbia disaster was very different than what led to the loss of Challenger , the investigation again found deep cultural problems at NASA.

The crew of STS, seen here, had their flight aboard Space Shuttle Columbia delayed 18 times before launching in While reentering Earth's atmosphere, Columbia broke apart, killing the entire crew. All of these factors — high costs, slow turnaround, few customers, and a vehicle and agency that had major safety problems — combined to make the Bush administration realize it was time for the Space Shuttle Program to retire.

In , President Bush gave a speech that outlined the end of the shuttle era, without clearly identifying what would come next or how much it would cost. This decision left NASA in limbo, as they were suddenly dependent on the Russians for access to space. The remaining three space shuttles, Discovery , Endeavour , and Atlantis , are now museum pieces, as is the test orbiter Enterprise.

Having seen some of these vessels in person, I can attest that they still are breathtaking sights to behold.

With SpaceX already launching humans into space, and with other commercial space ventures making rapid progress, the future of manned spaceflight under NASA seems unclear. Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter. View our Privacy Policy. By signing up you may also receive reader surveys and occasional special offers.

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Tonight's Sky — Enter coordinates. Columbia's mission included five spacewalks to service the Hubble Space Telescope; where astronauts replaced an aging power control unit, removed and installed solar arrays and conducted science instrument upgrades.

Servicing time hit a record, at the time, of 35 hours and 55 minutes, breaking the previous record of 35 hours and 28 minutes set by Hubble's first servicing mission STS, according to NASA. Space shuttle Columbia's final flight was STS, a nearly day research mission focusing on scientific experiments. On Feb. Controllers spent several minutes trying to hail the shuttle as the families of the astronauts waited at the expected landing site at the Kennedy Space Center.

As the communications blackout lengthened, and video footage emerged of a large flying object breaking into pieces , it became clear that the crew had not survived. According to a crew survival report released by NASA in , the crew likely lived through the initial breakup but fell unconscious quickly as the cabin depressurized. They died as the shuttle broke up around them. According to the crew survival report, their remains were retrieved from the ground and identified through DNA and dental records.

The Columbia Accident Investigation Board was formed to look at the causes of the breakup and to prevent it from happening again. Harold W. Gehman Jr. Joint Forces Command, chaired the board.

It included participation from a dozen people, including NASA officials and former astronaut Sally Ride , who was also a member of Challenger's investigation.

The board concluded that a piece of foam from Columbia's external tank hit the shuttle during launch and caused a fatal breach in Columbia's wing. This "foam debris" problem was well-known and documented in the years before Columbia's launch, but over time NASA grew to accept it as part of spaceflight.

The board recommended this problem be addressed. NASA made changes to the external tank as well as put in new safety procedures for shuttle missions. Among them, on every spaceflight, the crew was required to spend several hours scanning the shuttle's bottom for broken tiles. Several memorials have been dedicated to the crew as well. For example, seven asteroids that orbit the sun between Mars and Jupiter were named after the seven crew members of STS Visitors to the Kennedy Space Center can view debris from the Columbia mission as well as Challenger at an exhibit called "Forever Remembered," which opened in The debris is on display at the visitor's center and shows window frames from Columbia, as well as personal artifacts from the astronauts.

The families of the astronauts collaborated on creating the exhibit. Meanwhile, some of the experiments from Columbia's last flight returned useful data. This included a set of roundworms Caenorhabditis elegans that survived reentry and successfully reproduced. Some of the descendants flew in space aboard space shuttle Endeavour in May Join our Space Forums to keep talking space on the latest missions, night sky and more!

And if you have a news tip, correction or comment, let us know at: community space. Elizabeth Howell is a contributing writer for Space. She is the author or co-author of several books on space exploration. Elizabeth holds a Ph. She also holds a bachelor of journalism degree from Carleton University in Canada, where she began her space-writing career in Besides writing, Elizabeth teaches communications at the university and community college level, and for government training schools.

To see her latest projects, follow Elizabeth on Twitter at howellspace. Elizabeth Howell.