[Spaceflight History Blog ]What If a Shuttle Orbiter Struck a Bird? (1988)

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What If a Shuttle Orbiter Struck a Bird? (1988)
23 December 2017 David S. F. Portree


Final approach: the Shuttle Orbiter Discovery lands on the Shuttle Landing Facility at Kennedy Space Center, Florida, at the end of its longest mission (STS-131, 5-20 April 2010). Image credit: NASA

The first NASA astronaut to die in the line of duty was U. S. Air Force Captain Theodore Freeman. Little known today, Freeman was a member of the third astronaut selection group, which NASA introduced to the world on 18 October 1963. The group included 10 astronauts who would become famous - Michael Collins, Edwin Aldrin, Alan Bean, David Scott, Russell Schweickart, William Anders, Eugene Cernan, Walter Cunningham, Donn Eisele, and Richard Gordon - and three besides Freeman who would perish before reaching orbit - Clifton Williams, Roger Chaffee, and Charles Bassett. Of the seven pre-Shuttle NASA astronaut groups, Group 3 experienced more pre-flight astronaut deaths than any other.

The astronauts had at their disposal T-38 training aircraft, which they used to accumulate flight time so that they could maintain their piloting skills and flight status. On 31 October 1964, 34-year-old Freeman took one up from Ellington Air Force Base, located between downtown Houston, Texas, and NASA's Manned Spacecraft Center (MSC).


NASA's Third Astronaut Group. Theodore Freeman is in the back row, fourth from left. Image credit: NASA

As he returned to Ellington, a flock of Canadian geese took wing to one side of his flight path. As he made a turn, the flock rose up around his plane, and one bird struck and shattered the T-38's plexiglass forward canopy. Plexiglass shards entered the jet's twin air intakes. Moments later, its single engine began to fail.

The eight-pound goose did not enter the T-38's air intakes, though some sources report that it did. In fact, after striking the canopy, it struck the plane's rear seat, then rolled away along the jet's upper fuselage.

Freeman tried to line up with an Ellington runway, but the engine flamed out and his plane began a steep dive at low altitude. He ejected, but before his parachute could open he struck the ground and was killed.

In October 1983, nearly 20 years after Freeman's untimely death, The Christian Science Monitor published a puff piece on NASA's efforts to keep wild pigs and alligators off the 15,000-foot-long, 300-foot-wide Shuttle Landing Facility (SLF) runway at Kennedy Space Center (KSC) in Florida. The story was timely because NASA aimed to achieve its first SLF Orbiter landing in January 1984. The space agency had planned to land Challenger on the SLF runway at the end of mission STS-7 on 24 June 1983, but had diverted it to Edwards Air Force Base (EAFB) in California after KSC became fogged in.

The north end of the SLF is about a mile from the Visitor Center for the Merritt Island National Wildlife Refuge (MINWR). MINWR and KSC both owe their origins to President John F. Kennedy's 25 May 1961 "moon speech." In 1962-1963, NASA acquired more than 140,000 acres of orange groves, swamp, and beaches to create a safety buffer around its Apollo Saturn V launch pads and other facilities. As landowners moved out, sometimes grudgingly, wildlife moved in.

On 28 August 1963, the space agency and the U.S. Fish and Wildlife Service agreed that the latter would manage the roughly 90% of KSC that NASA did not actively use. The interagency agreement assumed that KSC activities would increase and its facilities expand. Apollo-related construction leveled off in 1966-1967, however.

Major new facilities expansion at KSC did not begin until April 1974, when Morrison-Knudsen Company began work on the $22-million-dollar SLF. The facility, modeled on flight research runways at EAFB, was completed in 1976 and put to work as an airport for astronaut T-38s, Gulfstream II Shuttle Training Aircraft, and other planes and helicopters. The first spaceworthy Orbiter, Columbia, arrived at the SLF atop a 747 carrier aircraft in March 1979.


The Shuttle Landing Facility. Image credit: NASA

A NASA spokesman told the Monitor's reporter that KSC played host to "all kinds of bald eagles, vultures, lots of brown pelicans, and ducks in winter." This was, however, not of great concern; the Shuttle Orbiter was a glider, he explained, so lacked air intakes that might ingest birds.

The Monitor reporter wrote that the Orbiter had "triple-strength windows." This was a reference to the design of the six windows making up the flight deck windshield; each was three panes thick, with empty spaces between the panes. The outermost pane, the "thermal" pane, was attached to the fuselage structure; the innermost pane, the "pressure" pane, was attached to the crew cabin structure. Between these, also attached to the crew cabin structure, was a thick "redundant" pane.

On its second try, at the end of mission STS 41-B (3-11 February 1984), Challenger glided to a safe landing on the SLF. NASA hailed the landing, little more than five miles from the launch pad Challenger had left just eight days before, as a major step toward routine Shuttle flights and Shuttle flight rates of up to 25 per year.

A little less than two years later, on 28 January 1986, Challenger disintegrated 73 seconds after liftoff from KSC's Pad 39B, killing its seven-person crew. The disaster revealed that the Shuttle stack - twin reusable Solid Rocket Boosters, expendable External Tank, and reusable delta-winged Shuttle Orbiter - was far less robust than many had assumed.

Under intense scrutiny, NASA commenced a wide-ranging examination of Space Shuttle systems and operations. The U.S. civilian space agency soon found that many of its comfortable assumptions were incorrect.


Shuttle windshield: the Orbiter Endeavour during mission STS-123 (11-27 March 2008). Image credit: NASA

NASA engineer Karen Edelstein and Robert McCarty of the Wright Aeronautical Laboratories at Wright-Patterson Air Force Base, Ohio, reported on results of their study of bird impacts on the Orbiter windshield. They determined that, far from being "triple-strength," it was "a poor barrier to bird impacts."

In fact, computer modeling showed that, in every case, a four-pound bird - for example, a typical turkey vulture - would penetrate the three windshield panes and enter the flight deck if the Orbiter were moving above an indeterminate speed between 150 knots (172 miles per hour) and 175 knots (201 miles per hour). They noted that the Orbiter traveled at about 300 knots (345 miles per hour) as it fell past 10,000 feet and only slowed to 195 knots (224 miles per hour) by the time its rear wheels touched the SLF runway. This meant that at no time during descent through altitudes where birds fly did the Orbiter's windshield provide protection from bird strikes.


A turkey vulture. Image credit: Wikipedia

Edelstein and McCarty noted that, short of a major redesign, there was little NASA could do to beef up the Orbiter windows. They urged designers of future space planes to seek materials more sturdy than glass when designing their windshields.

The Edelstein and McCarty paper did not lead to a major Orbiter redesign or new Orbiter window materials. Instead, NASA redoubled its efforts to scare birds away from the SLF. Mostly it relied on loud noises. For a time in the mid-1990s, KSC seriously considered hiring falconers; a June 1994 study noted that falcons had been used intermittently since the 1940s to scare birds away from airfields in the U.K., the Netherlands, Spain, France, Canada, and the United States. The study found, however, that most of the more than 300 bird species in MINWR had little experience with falcons, so were unlikely to be frightened by them.

The birds most threatening to Orbiters and other aircraft at the SLF, the 1994 study found, were various species of vulture. It noted that groups of up to 30 individuals were frequently found around a single roadkill and that a "roost" of 300 vultures had become established on the SLF's southern approach path. The birds, which weighed up to five pounds, took to the skies to ride thermals over KSC beginning in mid-morning. Mostly they glided lazily between 150 and 1800 feet above the ground. If they caught wind of carrion, however, they could move rapidly, thwarting efforts to track and deter them. Loud noises, effective in control of most other birds, were of little concern to vultures.

During the mid-morning launch of Discovery at the start of mission STS-114 on 26 July 2005, a large bird collided with the External Tank as the Shuttle stack cleared the tower. The bird, probably a vulture, was estimated to weigh about twice as much as the chunk of ice-impregnated foam insulation that had punched a gaping hole in Columbia's wing leading edge on 16 January 2003, at the start of mission STS-107. The damaged wing caused NASA's oldest Orbiter to break up during reentry on 1 February 2003, killing the seven-member STS-107 crew. Though it caused no damage, the bird strike during the STS-114 launch was especially disturbing because it was the first Shuttle mission since Columbia was destroyed.

After the STS-114 bird collision, KSC managers decided to apply SLF bird control techniques to the twin Shuttle launch pads. They also adopted a launch day vulture "trap-and-release" policy.

By 2009, KSC's Bird Abatement Program relied on quick removal of roadkill to pare down vulture numbers, bird detection radar and cameras, sirens, shotguns firing blanks and whistlers, and 25 liquid-propane-fueled "cannons." Installed along the SLF in 2007, the noise-producing cannons could be set off from the runway's control tower or by bird observers on the ground. They could also fire automatically at random times and in random directions. Despite these measures, the problem of bird strikes on Space Shuttles remained largely unresolved as the Orbiter Atlantis rolled to a stop on the SLF at the end of STS-135, the final Shuttle mission, in July 2011.

Sources

"Space Shuttle Orbiter Windshield Bird Impact Analysis," ICAS-88-5.8.3, K. Edelstein and R. McCarty, Proceedings of the 16th International Council on Aeronautical Sciences Congress held in Jerusalem, Israel, 28 August-2 September 1988, Volume 2, pp. 1267-1274

A Review of Falconry as a Bird Control Technique With Recommendations for Use at the Shuttle Landing Facility, John F. Kennedy Space Center, Florida, U.S.A., NASA Technical Memorandum 110142, V. Larson, S. Rowe, D. Breininger, and R. Yosef, June 1994

"History of the Shuttle Landing Facility at Kennedy Space Center," E. Liston and D. Elliot; paper presented at The (40th) Space Congress in Cocoa Beach, Florida, 28 April-2 May 2003

Fallen Astronauts: Heroes Who Died Reaching for the Moon, Revised Edition, C. Burgess and K. Doolan with B. Vis, University of Nebraska Press, 2016, pp. 1-45

"NASA Tries To Keep The Hogs and 'Gators Off the Shuttle's Runway," G. Klein, The Christian Science Monitor, 12 October 1983
- https://www.csmonitor.com/1983/1012/101225.html

"It's a Jungle Out There!" L. Herridge, 26 June 2006 - https://www.nasa.gov/mission_pages/shuttle/behindscenes/roadkill.html

"Bye, Bye, Birdies," C. Mansfield, 30 June 2006 - https://www.nasa.gov/mission_pages/shuttle/behindscenes/avian_radar.html

"Bird Team Clears Path for Space Shuttles," L. Herridge, 12 August 2009 - https://www.nasa.gov/mission_pages/shuttle/behindscenes/clearbirds.html

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