there are some people that will step up for one thing and not another. but it is the stepping up that we need to learn how to see, to with ourd to support gratitude and our resources. people who step up in times of valuablesis are unbelievably to every group and culture on the face of the earth. i think that how we treat those who do step up will determine the quality of those who subsequently step up. >> thank you so much for being with us. my pleasure. thank you. you are watching "american history tv." all weekend, every weekend on c-span3.

conversation, like us on facebook. [clapping and cheering] >> the first teacher in space. ago, january 28, 1986, the space shuttle challenger exploded 70 seconds after liftoff, taking the lives of the seven crew members pictured here. america," areel nasa report detailing the causes of the disaster. the conclusions are the findings released on june 6 of 1986. but first, the nasa video of the shuttle launch, followed by president reagan's remarks to the nation from the oval office

five hours after the accident. >> t -15 seconds. t -10, 9, 8, 7, 6 -- we have main engine start. liftoff.1, and liftoff, the 25th spatial mission has clear the towel -- tower. >> confirmed. challenger now heading downrange. engines have begun throttling down now. 94%. normal throttle for most of the plane. will throttle down to 65% shortly.

engines at 65%, three engines running normally. velocity, out the two, nautical miles, downrange distance three. engine is throttling up. 104%. >> challenger, go at throttle up. >> roger. >> one minute 15 seconds. altitude, nine nautical miles.

>> flight controllers here, looking carefully of the situation. obviously a major malfunction. we have no downlink. we have the report from the flight dynamics officer that the vehicle has exploded. we are looking at checking with recovery forces to see what can be done at this point. president reagan: ladies and gentlemen, i planned to speak to you about the state of the union . today's events let me to change those plans.

today is a day for morning and remembering. share this pain with all the people of our country. this is truly a national loss. 19 years ago, almost to the day, in ast three astronauts terrible accident on the ground. but we've never lost an astronaut in flight. we've never had a tragedy like this. perhaps we forgotten the courage that it took for the crew of the shuttle. they were aware of the dangers, overcame them and did their jobs brilliantly. we mourn seven euros. michael smith, vic scobee, judith resnick, ronald mcnair, , gregory jarvis, and christmas nickel. we mourn their loss as a nation together. we cannot bear as you do the full impact of this tragedy, but

we feel the loss and are thinking about you so very much. your loved ones were daring and brave. grace,d that special that special spirit that said -- give me a challenge and i will meet it with joy. they had a hunger to the 2 -- to explore the universe and its truths. they served all of us. wonders in used to this century. it's hard to dazzle us. but for 25 years the united states space program has done just that. we've grown used to the idea of space. perhaps we forget that we've only just begun. we are still pioneers. today the members of the challenger crew were pioneers. i want to say something to the schoolchildren of america who were watching the live coverage. i know it's hard to understand, but painful things like this happen. it's all part of the process of exploration and discovery.

it's all part of taking a chance and expanding man's horizons. the future doesn't belong to the fainthearted. it belongs to the brave. the challenger crew was pulling us into the future and we continue to follow. always had great faith in and respect for our space program. what happened today does nothing to diminish it. space program,ur keep secrets or cover things up. we do it all up front and in public. that's how freedom is and we wouldn't change it. we will continue our quest into space. there will be more shuttle flights, civilians, and teachers in space. nothing ends here. our hopes and our journeys continue. i want to add that i wish i could talk to every man and woman who works for nasa or who worked on this mission and tell them that your dedication and

professionalism have moved and impressed us for decades. your anguish. we share it. on this day 390 years ago the great explorer, sir francis drake, died on board a ship off the coast of panama. his great frontiers in his lifetime were the oceans. historians later said that he lived by the sea, died on it, and was buried in it. today we can say of the crew of the challenger that their dedication was, like his, complete. the crew of the space shuttle challenger honored us. we will never forget them, nor the last time that we saw them as they prepared for their journey and weight -- waved goodbye. ofpping the surly bonds earth to touch the face of god. thank you.

>> flight of the space shuttle atllenger, 51 nl, beginning 8:11 a.m. eastern standard time, january 28, 1980. it evident -- it ended 73 seconds later in the structural breakup in which the seven crew members perished. the solid rocket boosters continued in flight and were destroyed by the range safety officer 100 seconds after launch. the delivery and assembly of the launch vehicle components began months prior. boosterd rocket segments were transported by rail to the kennedy space center.

the esrb's were inspected and partially assembled at the rotation, processing, and storage facility. the the segments were then moved to the vehicle assembly building and stack on the mobile launch a form. the external tank arrived by thee and was moved into vab, where it was checked out and made it to the stacked solid rocket boosters. after orbiter checkout, challenger was rolled into the vab.

mating with the assembled external tank and srv's. the vehicle was transported from on vab to the launchpad december 22, 1985, crawling at approximately one mile per hour. the journey takes about six hours. the launch was rescheduled several times, resulting in the 28,l countdown on january 1986. the weather was forecast to be clear and cold, temperatures dropping into the low 20's overnight. ice had accumulated on the launchpad during the night. several water systems were open slightly and allowed to flow into drains. the drains flow -- froze and

caused overflows. high wind gust spread the water over large areas and ice form. the air temperature at launch was 36 degrees fahrenheit. this was 15 degrees colder than any previous launch. at t minus seven minutes 40 seconds the ground launch sequencer began retracting the crew access arm. it can be put back in place within 15 to 20 seconds if an emergency arises. at t minus three minutes 15 seconds, gimbel checks of the main engines were performed. all three engines move in a preprogrammed tattered to verify flight control. the gimbel sequence ends with the engines in their start decisions. at t minus three minutes 55

seconds, external liquid pressurization began and main engine purging was completed. retraction of the gaseous oxygen vent hood again. the ground launch sequencer verified its full retraction at t -37 seconds. sound suppression water was started at t minus 16 seconds. at t minus eight seconds, hydrogen make nighters were turned on to burn off any free hydrogen. 6.6 seconds before launch, challengers liquid fuel main engines were ignited in sequence and run up to full thrust. thrust from the main engines bounced the shuttle stack.

when it returned to vertical the solid rocket boosters ignited. then the holddown bolts were exclusively -- explosively released. after the initial motion, structural forces dissipated through vibration at a rate of three cycles per second during the first few seconds of flight. roll maneuver was initiated at seven 724 seconds. at maneuver was completed 21.124 seconds. >> 104%. throttling in. >> the main engines were throttled back to 35.379 second for about 16 seconds in order to alleviate mode during maximum dynamic pressure.

the engines were then throttled up to 104% at 51.19 seconds. >> challenger, go at throttled up. >> telemetry data gave no indication of problems. >> altitude, nine nautical miles. >> the solid rocket boosters continued in flight and were destroyed by the range safety officer 110 seconds after launch.

data from nearly 200 cameras were analyzed during the investigation. the following sequence of events is based on the evaluation of data.video, and telemetry this graphic indicates viewing angles for three cameras in the vicinity of the launch site. the first view is from camera 63 at the lower right of the chart. flight,seconds into the a strong puff of gray smoke nbc and squirting from the aft field joint. the vaporized material streaming from it indicates that there was not complete sealing action within the joint. this second view is from camera 60. the smoke can be seen between the right srv and external tank, initially moving in the upward direction. the angle between this view and e 63 is 170 degrees.

with 60 and 63 side-by-side, it is clear that when smoke is first visible to 60, it's not yet visible to 63. .2 seconds later it becomes visible and is seen in multiple lobes. a third, higher resolution camera was located east of the launchpad. 67 recorded this view at approximately the same time of mock -- maximum development with smoke appearing to the right side only. normal water condensation vapors appear to the left. this plan shows that none of the cameras directly view the surface of the shaded region of the graphic. analysis of film from several pad amorous indicate that the smoke came -- came from 370 to

210 degrees of the circumference of the aft field joint. as indicated on these chief flight photos, the smoke emerged between the esrb and et at a point along the longitudinal access -- axis near the aft field joint. smokeltiple puffs of occurred at a rate of four times per second, approximating the frequency of the structural load dynamics. this greatly exaggerated computer animation detects the taxing of the joint. this flexing increase the gap between the tang and the clevis. last evidence of smoke above the detached ring appears at 2.733 seconds. last indication of smoke below the dome appears at 3.75.

film the records of the assembly of the solid rocket booster were reviewed to determine evidence or cause for the smoke. photographs taken just prior to meeting of the segments of the aft wheel joint show that the o-ring installed had a subtle variation that was the tech could but through computer enhancement it was determined to be a shadow. no evidence of defects were observed in any of the stacking photography. the gaseous hydrogen vent arm was not captured after retraction at launch. film analysis shows that it did not contribute to the accident. post launch inspection of the holddown revealed that the kick spring assemblies on four of the posts were missing.

detailed analysis determined that the assemblies could not have become detached prior to t -850 milliseconds. next significant event was the development of the esrb burn through plume. camera 207, located six miles north of the launchpad, shows the growth of this plume. evidence of flames appeared on the right solid rocket booster at 58 .788 seconds. this occurred as the main engines have been throttled up and the esrb's were increasing thrust. camera 203 was located west of the launch site and gives an aft view. the exposure was set for the booster plumes.

this graphic illustrates the location of the player. the player was located near the aft field joint 300 degrees, consistent with the smoke at liftoff. within half a second the flame had grown into a continuous and well-defined plume. at the same time, telemetry showed a divergence in chamber pressures. pressure in the right srv chamber was lower as a result of the growing leak. the plume is seen here in pitching directly onto the and at about 60 seconds the control system element started to respond to the course is caused -- forces caused by the plume. theecorded on 207 and 204,

first visible indication of the anonymous plume had penetrated was seen in the abrupt change and color of the plume. this is an indication of hydrogen leaking from the external bank. at 64.705 seconds, a bright sustained low develop. telemetry data confirmed that 2.2 seconds later, 56.8 seconds later, the system could no longer maintain the normal re-pressurization rate. the tank pressure could no longer be maintained, indicating that it significantly had increased and was growing rapidly. 72.2 seconds, guidance systems show right motions diverging,

indicating the lower et esrb strut was severed or pulled loose. during this timeframe exaggerated command responses registered in the telemetry data. at a proximally 73 seconds liquid hydrogen and oxygen pressure to the main engines showed a significant drop. this was followed at 73.124 seconds by the appearance of the suggesting the structural failure. , weber wasonds later observed that the inner tank. tankative of the oxygen failing. with normal loads being induced by the formal attach point or from the propulsive forces created by the aft bulkhead daily. probably both.

within milliseconds liquid -- liquid oxygen was seen streaming along the external tank. at 73.191 seconds a flash was observed that was immediately followed by the start -- the start of total vehicle breakup. the next 100 milliseconds, additional flashes occurred in the forward attach areas. as it broke up, the released fluids broke open rapidly, releasing vapors and fluids that .ad them -- had embedded debris no shockwave or other evidence of a violent explosion was detected in the imagery. and it doestion give the crowd the appearance of . firewall

we are in automatic shutdown mode as a result of reduced propellant pressures. the last till on a tree was received after launch. essentially obscured by the vapor cloud, hundreds of fragments were noted exiting the cloud. those identified included the main engines of the shuttle, left wing, crew cabin and both srv's. approximately one second after initial breakup film showed the front section emerging from the cloud. nitrogen text -- niger's in tetra oxide from the further control systems provided a distinctive orange brown color to the cloud.

seconds -- 7.54 seconds later fragment was believed to be seen and caused by the forward rcs revealing a separation of the nose section from the crew cabin . list and one quarter of one second later it was noted to be severed from the cargo bay. igniting a propellant discharge observed from the forward rcs. the camera south of the launchpad reported a wider array of the exiting debate. the initial emergence of the crew cabin from this perspective was 75.237 seconds.

the initial path of the crew cabin from the vapor cloud carried it taught -- across the path of an adjacent contrail. the left wing became visible at 78.531 seconds. the main engines and crew cabin are also identifiable. it was seen again with the front end and top of the cabin visible. as the subject moved further away and dropped lower on the horizon, the quality of the image for visual analysis deteriorated rapidly. long-range tracking cameras atlowed the esrb's approximately 75.8 seconds the right srv was seen exiting the cloud.

right srv shows the after the breakup where the joints are clearly visible. except for the aft field joint. this confirmed the location of the plume along the longitudinal axis of the esrb. cap andrated nose deployed parachute are identified at approximately 76.4 seconds. the shockwave from the detonation of the linear shaped charge can be seen clearly. simultaneously the left srv was destroyed. at approximately 37 seconds, challenger had encountered the first of several expected high altitude wind shear conditions that lasted until about 64

seconds. these are best illustrated by the effect on the booster exhaust trails. the effective windshear was by thevely countered guidance, navigation, and control systems. reconstructions were aided by comparing exhaust trail shapes with photography. the reconstructed wins were used in trajectory analysis. several flashes in the plumes were observed during the flight. as similar flashes have been seen on several previous flights , they are considered not to have contributed to the accident. thatisible condensation appears here is created by shockwaves that develop as the vehicle passes through the speed of sound.

a large-scale search effort was initiated to recover the space shuttle debris. searchs, six underwater vessels, 33 aircraft participating in the operation. the pieces initially recovered were those found floating on the surface. the submarine fleet was used to locate and inspect underwater debris. objects identified as being important to the investigation were retrieved. 50% of the entire vehicle was recovered in the effort. the ocean search area was located at the edge of the gulfstream at cap's of up to 1200 feet.

approximately 93,000 square miles of ocean researched. the recovered hardware was brought to the logistics facility, where reconstruction efforts helped to verify the team's findings, as well as to analyze the structural breakup mechanics. facility, logistics parts were arranged on the floor according to their location on the vehicle. 45% of the orbiter itself was recovered. the debris confirmed that the orbiter and its payloads did not contribute to the cause of the accident and that the breakup was the cause -- the result of aerodynamic and explosive effect . shown here are parts of the orbiter forward fuselage structure.

extensive heating and erosion was detected on the right side of the orbiter. the paint was scorched and blackened on the side of the fuselage. thermal distress was apparent on the right letters speed brake. while the left showed little effect. thermal effects were also seen. the aft left side showed no apparent sign of heat damage. the remaining recovered parts showed no evidence of fire or explosion from within the vehicle. all three main engines were recovered and helped to verify that they did not contribute to the cause of the accident.

the external tank was similarly reconstructed. 25% of the liquid hydrogen tank, 80% of the inner tank and 5% to the liquid oxygen tank were recovered. most of the extra hardware was also recovered. the nose cap sustained very little damage. in general the recovered pieces were quite large. the foam insulation exhibited varying degrees of thermal effects, from extreme charring to practically no effect. the external tank range safety housed exclusive charges this --

exclusive charges in this tray and returned on detonated. the inner tank region showed signs of duckling in the four and aft direction. this would be consistent with the impulsive thrust that resulted in the loss from the aft section of the tank. failure with the right srv was caused by the rotation after the aft strut area failed. the stringers on the right-hand side show evidence of contact that match marks on the forward assembly. the section of the ring frame and aft dome was recovered in one piece.

the lower strut attachment fitting hedman pulled away. the effects of the anomalous plume can be seen on the external tank, including an area shielded by the attachment fitting. approximately 50% of solid rocket booster hardware was recovered. an ordinance storage facility was used to house the pieces, as some contained unburned propellant. thrusteen on the right match the contact areas shown previously on the inner tank stream -- inter-tank stringers. the size and location of the burn as indicated by the recovered debris were illustrated on an assembled booster. the aft center section of the joint shows a large hole at the

circumferential position. it is about 27 by 15 inches. the steelcase material showed evidence of hot gas erosion caused by products flowing through the opening. section showed a whole approximately 33 by 21 inches. the burned surface extended into attached strut-- region. the exterior surface featured a large heat affected area. the shape and location of this spot indicates impingement of locating gases. there was a small burn through in the case wall that appeared to have penetrated from the outside in, due to the impingement of hot gases from the anomalous plume.

rockete in the solid booster segments was a result of the joint leakage, determined to be the cause of the accident. presidential conclusion admitted that it was the failure of the pressure seal on the right socket motor. the failure was due to a faulty design, rendering it unacceptably vulnerable to a number of factors, including the effective temperature, physical dimensions, the character of materials, the effective reuse and processing and joint dynamic loading. more detailed analysis are contained in volume three in the report on the presidential commission of the space shuttle challenger accident.