SPACE SHUTTLE CHALLENGER disaster - WikiVidi Documentary

a wiki video documentaries production don't forget to Like and subscribe enjoy space shuttle Challenger disaster on January 28 1986 the NASA shuttle orbiter mission STS 51 liters in the tenth flight of broke apart 73 seconds into its flight killing all seven crew members which consisted of five NASA astronauts and two payload specialists the spacecraft disintegrated over the Atlantic Ocean off the coast of Cape Canaveral Florida at 11:39 est the disintegration of the vehicle began after an o-rin

g seal in its right solid rocket booster failed at liftoff the o-ring was not designed to fly under unusually cold conditions as in this launch its failure caused a breach in the SRB joint it sealed allowing pressurized burning gas from within the solid rocket motor to reach the outside and impinge upon the adjacent SRB aft filled joint attachment hardware and external fuel tank this led to the separation of the right hand SRB zaft filled joint attachment and the structural failure of the extern

al tank aerodynamic forces broke up the orbiter the crew compartment and many other vehicle fragments were eventually recovered from the ocean floor after a lengthy search and recovery operation the exact timing of the death of the crew is unknown several crew members are known to have survived the initial breakup of the spacecraft the shuttle had no escape system and the impact of the crew compartment with the ocean surface was too violent to be survivable the disaster resulted in a 32 month hi

atus in the shuttle program and the formation of the Rogers Commission a special commission appointed by United States President Ronald Reagan to investigate the accident the Rogers Commission found to NASA's organizational culture and decision-making processes had been key contributing factors to the accident with the agency violating its own safety rules NASA managers had known since 1977 that contractor Morton Thiokol design of the SRBs contained a potentially catastrophic floor in the o-ring

but they had failed to address this problem properly NASA managers also disregarded warnings from engineers about the dangers of launching posed by the low temperatures of that morning and failed to adequately report these technical concerns to their superiors what the Rogers Commission report did not highlight was that the vehicle was never certified to operate in temperatures that low the o-rings as well as many other critical components had no test data to support any expectation of a succes

sful launch in such conditions Bob Ebeling from fire can't comment it wer only qualified to 40 degrees dot what business does anyone even have thinking about 18 degrees we're in no man's land can you live a former NASA chief scientist who had worked the space shuttle program since its first mission stated in an official 2004 NASA publication violating a couple of mission rules was the primary cause of the Challenger accident Robert valor was one of two teacher in space candidates from New Hampsh

ire and he stated the day they finally flew the shuttle Challenger I never thought they would because it was in fact a very cold morning and the shuttle was just not designed to fly under those conditions as a result of the disaster the Air Force decided to cancel its plans to use the shuttle for classified military satellite launches from Vandenberg Air Force Base in California deciding to use the Titan 4 instead approximately 17% of Americans witnessed the launch live because of the presence o

f payload specialist Christa McAuliffe who would have been the first teacher in space media coverage of the accident was extensive one study reported that 85% of Americans surveyed had heard the news within an hour of the accident the Challenger disaster has been used as a case study in many discussions of engineering safety and workplace ethics pouring concerns each of the space shuttles two solid rocket boosters was constructed of seven sections six of which were permanently joined in pairs at

the factory for each flight before resulting segments were then assembled in the Vehicle Assembly Building at Kennedy Space Center with three fielded joints the factory joints was with asbestos silica insulation applied over the joint while each filled joint was sealed with two rubber o-rings the seals of all of the SRB joints were required to contain the hot high-pressure gases produced by the burning solid propellant inside thus forcing them out of the nozzle at the aft end of each rocket dur

ing the space shuttle design process a McDonnell Douglas report in September 1971 discussed the safety record of solid rockets while a safe abort was possible after most types of failures one was especially dangerous a burn through by hot gases of the Rockets casing the report stated that if burn through occurs adjacent to liquid hydrogen / oxygen tank or orbiter timely sensing may not be feasible and abort not possible accurately foreshadowing the Challenger accident morton-thiokol was the cont

ractor responsible for the construction and maintenance of the shuttles SRBs as originally designed by thighik on the o-ring joints in the SRBs was supposed to close more tightly due to forces generated a technician but a 1977 test showed that when pressurized water was used to simulate the effects of booster combustion the metal parts bent away from each other opening a gap through which gases could leak this phenomenon known as joint rotation caused a momentary drop in air pressure this made i

t possible for combustion gases to erode the o-rings in the event of widespread erosion a flame path could develop causing the joint to burst which would have destroyed the booster and the shuttle engineers at the Marshall Space Flight Center wrote to the manager of the solid rocket booster project george hardy on several occasions suggesting that vehicles filled joint design was unacceptable for example one engineer suggested that join through rotation would render the second rearing useless bu

t hardy did not forward these memos to fire Cohn and the field joints were accepted for flight in 1980 evidence of serious o-ring erosion was present as early as the second space shuttle mission STS 2 which was flown by Columbia contrary to NASA regulations the Marshall Center did not report this problem to senior management at NASA but opted to keep the problem within their reporting channels with fire coal even after the o-rings were re-designated as criticality one meaning that their failure

would result in the destruction of the orbiter no one at Marshall suggested that the shuttles be grounded until the floor could be fixed after the 1984 launch of STS 41 D flown by a discovery the first occurrence of hot gas blow by was discovered beyond the primary o-ring in the post-flight analysis vehicle engineer's found that the amount of glow by was relatively small and had not impinge upon the second REO ring and concluded that for future flights the damage was an acceptable risk however a

fter the Challenger disaster vehicle engineer Brian Russell identified this event as the first big red flag regarding oring safety by 1985 with seven of nine shuttle launches that here using boosters displaying a ring erosion and/or hot gas blow by Marshall and Thea Cole realized that they had a potentially catastrophic problem on their hands perhaps most concerning was the launch of sts-1 B in April 1985 flown by Challenger in which the worst o-ring damage to date was discovered in post-flight

analysis the primary o-ring of the left nozzle had been eroded so extensively that it had failed to seal and for the first time hot gases had eroded the second REO ring they began the process of redesigning the joint with three inches of additional steel around the tang this Tang would grip the inner face of the joint and prevent it from rotating they did not call for a halt to shuttle flights until the joints could be redesigned but rather treated the problem is an acceptable flight risk for ex

ample Lawrence Malloy Marshalls manager for the SRB project since 1982 issued an wave launch constrains for six consecutive flights vehicle even went as far as to persuade NASA to declare v o-ring problem closed Donald kutina a member of the Rogers Commission later liken this situation to an airline permitting one of its planes to continue to fly despite evidence that one of its wings was about to fall off delays charger was originally set to launch from Caius se in Florida at 1442 Eastern Stand

ard Time on January 22nd 1986 delays in the previous mission sts-61 C caused the launch date to be moved to January 23rd and then to January 24th the launch was then rescheduled to January 25th due to bad weather at the transoceanic abort landing site in Dhaka Senegal NASA decided to use Casablanca as the trial site but because it was not equipped for night landings the launch had to be moved to the morning predictions of unacceptable weather at Caius say On January 26th caused the launch to be

rescheduled for 937 est on January 27th the launch was delayed the next day due to problems with the exterior access hatch first one of the microswitch indicators used to verify that the hatch was safely locked malfunctioned then a stripped bolt prevented the closeout crew from removing a closing fixture from the orbiters hatch by the time repair personnel had soared the fixture off crosswinds of the shuttle landing facility exceeded the limits for a return to launch site abort while the crew wa

ited for winds to die down the launch window expired forcing yet another scrub vehicle NASA conference call forecasts for January twenty-eighth predicted an unusually cold morning with temperatures close to minus one C the minimum temperature permitted for launch the shuttle was never certified to operate in temperatures that low the o-rings as well as many other critical components had no test data to support any expectation of a successful launch in such conditions by mid 1985 Thiokol engineer

's worried that others did not share their concerns about low temperatures effects on the boosters for beveling in October 1985 wrote a memo titled help so others would read it of concerns regarding low temperatures and no rings after the weather forecast NASA personnel remembered fire calls warnings and contacted the company when a fire calm manager are stabling about the possibility of a launch at 18 degrees he answered wer only qualified to 40 degrees . what business does anyone even have thi

nking about 18 degrees we're in no man's land after his team agreed that a launch risk disaster vehicle immediately called NASA recommending a postponement until temperatures rose in the afternoon NASA manager Judd lovingood responded that fire call could not make the recommendation without providing a safe temperature the company prepared for a teleconference two hours later during which it would have to justify a no launch recommendation at the teleconference on the evening of January 27th veh

icle engineers and managers discussed the weather conditions with NASA managers from a Kennedy Space Center and Marshall Space Flight Center several engineers reiterated their concerns about the effect of low temperatures on the resilience of the rubber o-rings that seal the joints off the SRBs and recommended a launch postponement they argued that they did not have enough data to determine whether the joints would properly seal if the o-rings were colder than 12c this was an important considera

tion since the SRB earings had been designated as a criticality one component meaning that there was no backup if both the primary and secondary o-rings failed and their failure could destroy the orbiter and kill its crew vehicle management initially supported its engineers recommendation to postpone the launch but NASA staff opposed a delay during the conference call Heidi told fire Conn I am appalled I am appalled by your recommendation Malloy said my god fire Conn when do you want me to launc

h next April NASA believed that vehicles hastily prepared presentations quality was too poor to support such a statement on flight safety one argument by NASA personnel contesting fire calls concerns was that if the primary o-ring failed the second REO ring would still seal this was unproven and was in any case an argument that did not apply to a criticality one component as astronaut Sally Ride stated when questioning NASA managers before the Rogers Commission it is forbidden to rely on back up

for a criticality one component NASA claimed that it did not know of theokoles earlier concerns about the effects of the cold on the o-rings and did not understand that Rockwell International the scheffel's prime contractor viewed the large amount of ice present on the pad as a constraint to launch for reasons that are unclear vehicle management reversed itself and recommended that the launch proceed as scheduled NASA did not ask why a dwelling told his wife that night that challenger would blo

w up can he live a former NASA chief scientist who had worked on the space shuttle program since its first mission stated in 2004 violating a couple of mission rules was the primary cause of the Challenger accident ice the fire pole engineer's had also argued that the lower overnight temperatures would almost certainly result in SRB temperatures below their redline off for sea ice had accumulated all over the launch pad raising concerns that ice could damage the shuttle upon liftoff the kennedy

ice team inadvertently pointed an infrared camera at the aft field joint of the right SRB and found the temperature to the only minus 13 c this was believed to be the result of supercooled air blowing on the joint from the liquid oxygen tank vent it was much lower than the air temperature and far below the design specifications for the earrings the low reading was later determined to be erroneous the error caused by not following the temperature probe manufacturer's instructions tests and adjust

ed calculations later confirmed that the temperature of the joint was not substantially different from the ambient temperature the temperature on the day of the launch was far lower than had been the case with previous launches below freezing at minus two point two two previously the coldest launch had been at 12 C although the ice team had worked through the night removing ice engineers at Rockwell still expressed concern Rockwell engineers watching the pad from their headquarters in Downey Cal

ifornia were horrified when they saw the amount of ice they feared that during launch ice might be shaken loose and strike the shuttles thermal protection tiles possibly due to the aspiration induced by the jet of exhaust gas from the SR B's Rocko Patroni the head of Rockwell's space transportation division and his colleagues viewed this situation as a launch constraint and told Rockwell's managers at the Cape that Rockwell could not support a launch rock rails managers at the gate voiced their

concerns in a manner that led houston-based mission manager Arnold Aldrich to go ahead with the launch Aldrich decided to postpone the shuttle launch by an hour to give the ice team time to perform another inspection after that last inspection during which the ice appeared to be melting challenger was cleared to launch at 11:38 a.m. EST liftoff and initial ascent the following account of the accident is derived from real-time telemetry data and photographic analysis as well as from transcripts o

f air-to-ground and Mission Control voice communications all times are given in seconds after launch and correspond to the telemetry time codes from the closest instrumented event to each described event the space shuttle main engines were ignited at t 6.6 seconds the SS Emmys were liquid fueled and could be safely shut down until the solid rocket boosters ignited at t 0 and the hold-down bolts were released with explosives freeing the vehicle from the pad at liftoff the three SS Emmys were at 1

00% of their original rated performance and began throttling up to 104 percent under computer control with the first vertical motion of the vehicle the gaseous hydrogen vent arm retracted from the external tank but failed to latch back review a film shot by pad cameras showed that the arm did not free contact the vehicle and thus it was ruled out as a contributing factor in the accident the post launch inspection of the pad also revealed that kick springs on four of the hold-down bolts were miss

ing but they were similarly ruled out as a possible cause later review of launch film showed that at t plus 0.6 hundred and seventy eight strong puffs of dark gray smoke were emitted from the right-hand SRB in near the aft strut that attached the booster to the et the last smoke puffs occurred at about t + 2 dot 733 the last view of smoke around the was at t-plus 3 dot 375 it was later determined that these smoke puffs were caused by the opening and closing of the aft field joint of the right ha

nd SRB the Boosters casing had ballooned under the stress of ignition as a result of this ballooning the metal parts of the casing bent away from each other opening a gap through which hot gases above 2,760 sea leaked this had occurred in previous launches but each time the primary o-ring had shifted out of its groove and formed a seal although the SRB was not designed to function this way it appeared to work well enough and morton-thiokol changed the design specs to accommodate this process kno

wn as extrusion while extrusion was taking place hot gases leaked past damaging the o-rings until a seal was made investigations by morton-thiokol engineers determined that the amount of damage to the o-rings was directly related to the time it took for extrusion to occur and that cold weather by causing the o-rings to harden lengthened the time of extrusion on the morning of the disaster the primary o-ring had become so hard due to the cold that it could not seal in time the temperature had dro

pped below the glass transition temperature of the earrings above the glass transition temperature the o-rings display properties of elasticity and flexibility while below the glass transition temperature they become rigid and brittle the second REO ring was not in its seated position due to the methyl bending there was now no barrier to the gases and both though rings were vaporized across 70 degrees of Arc aluminium oxides from the burnt solid propellant sealed the damaged joint temporarily re

placing the o-ring seal before flame passed through the joint as the vehicle cleared the tower the ssmes were operating at 104 percent of their rated maximum thrust and control switched from the launch control center at Kennedy to the Mission Control Center at Johnson Space Center in Houston Texas to prevent aerodynamic forces from structurally overloading the orbiter at t plus 28 the ssmes began throttling down to limit the velocity of the shuttle in the dense lower atmosphere per normal operat

ing procedure at t plus 35 dot 379 the ssmes throttled back further to the planned 65% 5 seconds later at about 19 thousand foot challenge' passed through Mach 1 at T plus 50 1.8 hundred and 60 the SS Emmie's began throttling back up to 104 percent as the vehicle passed beyond max-q the period of maximum aerodynamic pressure on the vehicle [Music] brought to you by wiki vide documentaries would you like to know more