and we're missing our leader because truth be told, most of them can't carry a tune. >> and supreme court curator catherine fits curator katherine fitz will talk about culinary secrets. the hard-fought 2016 primary season is over with historic conventions to follow this summer. >> coll. >> florida. >> texas. >> ohio. >> watch c-span as the delegates consider the nomination of the first woman ever to head a major political party and the first non-politician in several decades. watch live on c-span. listen on the c-span radio app or get video on demand at c-span.org. you have a front row seat to every minute of both conventions on c-span. all beginning on monday, july

18th. >> pilot mike smith, followed by christa mcauliffe. payload specialist greg jarvis. 30 years ago on january 28, 198, the space shuttle "challenger" 73 seconds after lift-off taking the lives of seven crew members pictured up. up next on american history tv's "reel america," a 1986 nasa video report detailing the causes of the disaster. the conclusions are the findings of the presidential commission on the space shuttle accident released on june 6 of 1986. first, nasa's video of the shuttle launch followed by president reagan's remarks to the nation from the oval office about five hours after the accident.

t minus 15 seconds. t minus ten, nine, eight, seven, six -- we have main engine start -- four, three, two, one, and lift-off. liftoff of the 25th space shuttle mission. and it has cleared the tower. >> rock and roll, "challenger." >> confirmed. >> "challenger" now heading down range. engines beginning throttling down. at 94%. normal throttle for most of the flight, 104%. will throttle down to 65% shortly.

engines at 65%. three engines running normally, three good fuel cells. velocity 2,257 feet per second. .243 naught call miles. engines throttling up. three engines at 104%. >> "challenger" go with throttle up. >> down range distance seven nautical miles.

>> flight controllers here looking very carefully at the situation. obviously, a major malfunction. we have no down link. we have a report from the flight dynamics officer that the vehicle has exploded. flight director confirms that. we are looking at checking with the recovery forces to see what can be done at this point. >> ladies and gentlemen, i had planned to speak to you tonight to report on the state of the union. the events of earlier today have led me to change those plans.

today is a day for mourning and remembering. nancy and i are pained to the core over the tragedy of the shuttle "challenger." we know we share this pain with all of the people of our country. this is truly a national loss. 19 years ago, almost to the day, we lost three astronauts in a terrible accident on the ground. but we have never lost an astronaut in flight. we had never had a tragedy like this. perhaps we forgotten the courage it took for the crew of the shuttle. but they, the "challenger" seven, were aware of the dangers and overcame them and did their jobs brilliantly. we mourn seven heros. mig the we mourn their loss as a nation together. the families of the seven we cannot bear as you do the full

impact of this tragedy. but we feel the loss and we're thinking about you so very much. your loved ones were daring and brave and they had that special grace, that special spirit that says, give me a challenge and i will meet it with joy. they had a hunger to explore the universe and discover its truths. they wished to serve and they did. they served all of us. we have grown used to wonders in this century. it's hard to dazzle us. but for 25 years, the united states space program has been doing just that. we have grown used to the idea of space and perhaps we forget that we have only just begun. we're still pioneers. they, the members of the "challenger" crew, were pioneers. and i want to say something to the schoolchildren of america who were watching the live coverage of the shuttle's takeoff. 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 will continue to follow them. i have always had great faith in and respect for our space program. and what happened today does nothing to diminish it. we don't hide our space program. we don't keep secrets and cover things up. we do it all up front and in public. that's the way freedom is and we wouldn't change it for a minute. we will continue our quest in space. there will be more shuttle flights and more shuttle crews and, yes, more volunteers, more civilians, more 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, your dedication and professionalism have moved and impressed us for decades and we know of your anguish. we share it. there's a coincidence today. on this day 390 years ago, the great explorer sir francis drake died aboard ship off the coast of panama. in his lifetime, the great frontiers were the oceans and a great historian later said he lived by the sea, died on it, and was buried in it. well, today we can say of the "challenger" crew, their dedication was like drake's -- complete. the crew of the space shuttle "challenger" honored us by the manner with which they lived their lives. we will never forget them, nor the last time we saw them this morning as they prepared for their journey and waved good-bye and slipped the surly bonds of earth to touch the face of god.

thank you. >> flight of the space shuttle "challenger" on mission 51-l. the 25th flight of the space shuttle program began at 1 1:38 a.m. eastern standard time on january 28, 1986. it ended 73 seconds later in a structural breakup of the external tank and orbitor in which the seven crew members perished. the solid rocket boosters continued in flight and were destroyed by the range safety officer 110 seconds after launch. >> the delivery and assembly began months prior to launch. the solid rocket booster segments were transported by rail to the kennedy space

center. the srbs were inspected and partially assembled at the rotation processing and storage facility. the segments were then moved to the vehicle assembly building, or vab, where they were stacked on the mobile launch platform. the external tank arrived by barge and was moved into the vab where it was checked out and mated to the stacked solid rocket boosters. after orbiter checkout, "challenger" was rolled into the

vab and mated with the external tank assembled and srbs. the sts 51-l vehicle was transported from the vab to the launchpad on december 22, 1985. at a crawler speed of approximately one mile per hour, the journey takes about six hours. the launch was rescheduled several times, resulting in the final countdown on january 28, 1986. the weather was forecast to be clear and cold with temperatures dropping into the low 20s overnight. the fuelling of the external tank began at 1:25 a.m. ice had accumulated on the launch pad during the night. several water systems were opened slightly and allowed to flow into drains. the drains froze and caused

overflows. high wind gusts spread the water over large areas and ice formed. the air temperature at launch was 36 degrees fahrenheit. this was 15 degrees colder than any previous launch. at t minus seven minutes and 30 seconds, the ground launch sequencer began retracting the crew access arm. the arm can be put back in place within 15 to 20 seconds if an emergency arises and the crew must evacuate the pad. at t minus three minutes and 15 seconds, checks of the main engines were performed. all three engines move in a preprogrammed pattern to verify ascent flight control. the sequence ends with the engines in the start positions.

at t minus two minutes and 55 seconds, external tank liquid oxygen pressurization began and main engine purging was completed. at t minus two minutes and 50 seconds, retraction of the gaseous oxygen reventer began. the ground launch sequence verified full retraction at t minus 37 seconds. sound suppression water was started at t minus 16 seconds. at t minus eight seconds, hydrogen igniters were turned on to burn off any free hydrogen. 6.6 seconds before launch, "challenger" ooh "challenger's" liquid fueled main engines were ignited in sequence and run up to full thrust. thrust from the main engines

bends the shuttle stack. when it returned to vertical, the solid rocket boosters ignited. at t zero the hold-on bolts were explosively released. after the initial prerelease motion, structural forces on the assembly are dissipated through vibration at a rate of three cycles per second during first few seconds of flight. rollover was initiated at 7.247 seconds. the maneuver was completed at 21.124 seconds. >> normal throttle for most of the flight, 104%. full throttle down to 65%. >> the main engines were throttled back to 65% at 35.379 seconds for about 16 seconds in order to alleviate loads during maximum dynamic pressure.

>> altitude 4.3 nautical miles. >> the engines were then throttled up to 104% at 51.919 seconds. >> "challenger," go with throttle up. >> during the flight, telemetry data gave no indication of problems. >> cruise at 15 seconds. velocity 1,900 feet per second. down range distance, seven 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 film, video and telemetry data. this graphic indicates viewing angles for three cameras in the vicinity of the launch sight. the first view shown is from camera heche-63 at the lower ri of the chart. at .678 seconds into the flight, a strong puff of grey smoke can be seen spurting from the vicinity of the aft field joint on the ride side of the solid booster. the material streaming from the joint indicates there was not complete sealing action within the joint. this second view is from camera e-60. the smoke can be seen between the right srb and the external tank and initially moves in the upward direction. the angle between this view and e-63 is approximately 100 degrees.

with e-60 and e-63 side by side, it's clear when smoke is first visible to camera e-60, it is not yet visible to e-63. .2 seconds later it becomes visible and is seen in multiple puffs reaching maximum visibility at about 1.9 seconds. a third higher resolution camera d-67 was located east of the launch pad. d-67 recorded this view of the smoke at approximately the same time of maximum development. smoke appears to the right side of the srb only. while normal water condensation vapors appear to the left. this plan shows that none of the cameras directly view the surface of the right srb in the shaded region of the graphic. analysis of film from several

pad cameras indicated that the smoke came from between 270 and 310 degrees on the circumference of the joint. as indicated on these pre-flight photos, the smoke emerged from just above the strut between the srb and et at a point along the longitudinal axis near the aft field joint. the multiple smoke puffs occurred at a rate of four times per second, approximating the frequency of the structural load dynamics and resultant joint flexing. this greatly exaggerated computer animation depicts the flexing of the srb joint. this flexing increased the gap between the tang and clevice at the location of two rubber o-ring seals. last evidence of smoke above the aft detach ring is at 7.23

seconds. the last appearance is 3.375 seconds. film records of the assembly of the solid rocket booster were reviewed to determine any evidence of cause for the smoke. photographs taken just prior to mating of the booster joints show a subtle variation but through computer enhancement was determined to be a shadow causes by irregularities in the grease. no evidence of o-ring defects was observed in any of the stacking photograph. the facility gaseous hydrogen vent arm was not captured after retraction at launch. film analysis however showed that it did not rebound and contact the vehicle or contribute to the accident. post launch inspection of the hold-down posts revealed that the kick spring assembles on

four of the posts were missing. detailed analysis determined that the assemblies could not have become detached prior to t plus 850 milliseconds and were not a contributing factor to the smoke observed at lift-off. the next significant event was the development of srb burn-through plume. camera e-207 located about six miles north of the launch pad shows the growth of this plume. the first evidence of flame appeared on the right solid rocket booster at 58.788 seconds. this occurred as the main engines had been throttled up to 104% thrust and the srbs were increasing thrust. camera e-203 was located west of the launch site and gives an aft view. the exposure was set for the booster nozzle plumes.

this graphic illustrates the location of the flare. the flare was located near the aft field joint approximately 300 degrees circumferentially which is consistent with the smoke emissions at lift-off. 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 between the right and left srbs. pressure in the right srb chamber was lower as a result of the growing leak. the plume is seen here on the surface of the external tank and lower aft strut. at 60.248 seconds. at about 62 seconds the control system elements began to respond to the forces caused by the plume.

as recorded on e-207 and e-204, the first visual indication that the plume penetrated the external tank was seen at 64.66 seconds as an abrupt change in the shape and color of the plume. this is an indication of hydrogen leaking from the external tank. at 64.705 seconds, a bright sustained glow developed between the orbiter and the external tank. slight changes in the hydrogen tank pressure telemetry data confirmed the leak 2.2 seconds later at 66.8 seconds. when the lh-2 tank pressurization could no longer maintain its normal repressurization rate at. at 72.6 seconds the pressure could no longer be maintained indicating the leak path had increased and was growing rapidly. at 72.2 seconds, the guidance

system showed that right srb motion diverged from the orbiter and left srb indicating the lower srb strut was severed or pulled loose. during this time frame, exaggerated steering command and control system responses registered in telemetry data. at approximately 73 seconds, both liquid hydrogen and liquid oxygen pressure to the main engines showed a significant drop. this was followed at 73.124 seconds by the appearance of a white pattern around the et aft region suggesting lh-2 tank structural failure. 13 milliseconds later, at 73.137 seconds, vapor was observed at the intertank indicative of the liquid oxygen tank failing. this can be attributed to abnormal loads induced by the right srb rotation at the forward attach point or the propulsive forces created by the

tank head failure. probably both. within milliseconds, liquid oxygen was observed streaming along the external tank. at 73.191 seconds, a flash was observed between the et and orbiter that was immediately followed by the start of total vehicle break-up at 73.213 seconds. during the next 100 milliseconds, additional flashes occur in the srb forward attach area. as the et broke up, the released fluids vaporized rapidly producing an expanding cloud of gases, videotapers and cryogenic fluid with embedded debris and localized combustion of mixed gases. no shock wave or other evidence of a violent explosion was detected in the imagery. illumination from a combination of srb plume radiance, reflective sunlight and burning of gases gives the cloud the

appearance of a fireball. by 73.6 seconds, the main engines were in automatic shutdown mode as a result of pressure. the last telemetry from "challenger" was received 73.618 seconds after launch. the actual vehicle break-up was essentially obscured from view by the videotaper cloud which abruptly enveloped the vehicle. hundreds of fragments were noted exiting the et cloud. those identified included the shuttle main engines, left wing, crew cabin and both srbs. approximately one second after initial breakup, film showed the front segment of the orbiter emerging from the cloud. the nose, crew cabin and a portion of the cargo bay make up the orbiter in this vi. oxygen from the control system

provided a distinct orange brown color to the cloud. by 74.578 seconds a flash was visible near the orbiter nose segment, believed to be caused by burning from the forward rcs. the flash reaction from the rcs propellants abated rye veelg separation of the nose section from the crew cabin. less than a quarter of a second later, the crew cabin was noted to be severed from the cargo bay. igniting a discharge continued to be observed from the forward rcs. a camera south of the launch pad recorded a wider array of debris existing the vapor cloud. the initial emergence of the crew cabin from this perspective

was at 75.237 seconds. the initial path of the crew cabin from the vapor cloud carried it across the path of an adjacent trail clearly revealing its turning aruncated form and . the left wing became visible at 78.531 seconds. the main engines and crew cabin are also identifiable. after ten seconds, the crew cabin 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 followed the srbs through safety destruct. at approximately 75.8 seconds, the right srb was seen exiting the cloud.

camera e-207 shows the right srb after the breakup and the joints are clearly visible except for the aft field joint. this confirmed the location of the plume along the longitudinal axis of the srb. the separated nose cap and deployed parachute are identified at approximately 76.4 seconds. the shock wave from the debt nation debt nation of the lynn detonation of the charge on the right srb can be seen clearly. detonation of the charge on the right srb can be seen clearly. simultaneously, the left srb was destroyed. at approximately 37 seconds, "challenger" had encountered the

first of several expected high altitude wind sheer conditions which lasted until about 64 seconds. these wind sheers are best illustrated by the effect on the booster exhaust trails. the effect of wind shear was immediately sensed and countered by the guidance, navigation and control system. wind reconstructions were aided by comparing predicted exhaust trail shapes with acquired photography. the reconstructed winds were used in trajectory and flight loads analyses which verified that the loads were within limits. several flashes in the ssme 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. the visible condensation that appears in this frame is created by shock waves which develop as the vehicle passes through the speed of sound.

a large scale search effort was initiated to recover the space shuttle debris. 22 ships, 6 underwater search vessels and 33 aircraft participated in the operation. the pieces recovered initially 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 depths of up to

1,200 feet. approximately 93,000 square miles of ocean were searched. the recovered hardware was brought to the logistics facility where reconstruction efforts helped to verify the investigation team's findings as well as to analyze the structural breakup of the mechanics of the orbiter, et and srbs. inside the logistics facility, parts were arranged on the floor according to their location on the vehicle. 45% of the orbiter itself was recovered. the debris confirmed the orbiter around its payloads did not contribute to the cause of the accident and the orbiter breakup was the result of aerodynamic effects rather than explosive effects. shown here are parts of the orbiter forward fuselage structure which surrounds the crew cabin.

extensive heating and erosion was detected on the right aft section of the orbiter. the paint was scorched and blackened on the right side of the aft fuselage. thermal distress was apparent on the right rudder speed brake while the left showed little effect. thermal effects were also seen on the elevan. the aft left side of the orbiter showed no apparent sign of heat damage. the remaining recovered parts of the orbiter 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% of the liquid oxygen tank was recovered. most of the external hardware was also recovered. the nose cap sustained very little damage. in general, the recovered pieces were quite large. the spray-on foam insulation exhibited varying degrees of thermal effects from extreme charring to practically no effect. the external tank range safety

charges housed in this cable tray were recovered undetonated, eliminating them as a possible factor in external tank breakup. the inner tank region showed signs of buckling in the fore and aft direction. this would be consistent with the impulsive thrust that resulted from the sudden liquid oxygen from the aft section of the tank. this shearing failure of the forward attachment fitting with the right srb was caused by the booster's rotation after the aft strut area failed. the stiffener stringers on the right-hand side of the inner tank show evidence of contact which matched marks on the forward assembly of the right srb. a section of the ring frame and a section of the aft dome from

the lower strut attachment area was recovered in one piece. the lower strut attachment fitting had been pulled away. the effects of the anomalous srb plume can be seen on the external tank excluding an area which was shielded by the strut and attachment fitting. approximately 50% of solid rocket booster hardware was recovered. an ordnance storage facility was used to house the motor case pieces as some contained unburned propellant. marks seen on the right srb matched the contact area shown previously on the et inner tank stringers. the size and location of the burn-through as indicated by the recovered srb debris were illustrated on an assembled booster. the aft center section of the

joint shows a large hole centered at the 307 degrees s circumference position. the irregular hole is roughly rectangular and is about 27 by 15 inches. the steel case material showed evidence of hot gas erosion caused by combustion products flowing through the opening. the aft section of the right srb showed a hole approximately 33 by 21 inches. the burned surface extended into the aft attached strut region. the exterior surface of the aft case featured a large heat-affected area. the shape and location of this heat spot indicates an impingement from the escaping gases. there was a small burn-through in the case wall which appeared to have penetrated from the outside in. this was due to the impingement

of hot gases from the anomolous plume. the hole in the solid rocket booster segments was the result of the joint leakage on the right hand srb which was determined to be the cause of the accident. the presidential commission concluded that the cause of the "challenger" accident was the failure of the pressure seal in the aft field joint of the right solid rocket motor. the failure was due to a faulty design, rendering the seal unacceptably sensitive to a number of factors. those factors include the effects of temperature, physical dimensions, the character of materials, the effects of reuse and processing and the reaction of the joint to dynamic loading. more detailed analyses are contained in volume three of the report of the presidential commission on the space shuttle "challenger" accident.

the smithsonian national air and space museum is celebrated its 40th anniversary today. join us starting at 6:00 p.m. eastern when we'll be live from the museum taking your calls and questions about aviation and space history. that's today at 6:00 p.m. here on american history tv on c-span3. this weekend on c-span cities tour, along with our comcast cable partners we'll explore the history and literary life of provo, utah. book tv we'll visit moon's rare books. reid moon, the store's proprietor, has been collected books from all over the world for the last 30 years. he has many great finds. >> thomas payne went to robert bell, wanted to have this

printed and he wanted the proceeds to buy the soldiers mittens. well, after it went through three printings, they had a falling out, and so thomas payne allowed anybody to print it. he lowered the price and said anybody can print it. that's one reason that book is so well known and printed. >> and jay spencer fluman talks about antimormonism in america since its founding in the 1830s through their current struggles as a religious minority and the origins of the animosity. >> latter day saints fit in with that. they are a religious minority who over time have figured in disproportionate ways. >> see the dinosaur fossils collected by dr. james a. jensen, curator of the museum, rod sheets, talks about how the

fossils were gathered from utah and surrounding states and how do jensen changed the way fossils and bones are displayed. >> when you can hide the armature and the steel supports, the animal looks more alive in the sense that you get the feeling that these are bones, but it brings life to these bones. >> and jay spencer fluman, professor of history at brigham young university talks about how the mormons settles and 33 mormon families established the settlement of provo in 1849. this weekend watch c-span's cities tour to provo, utah. saturday at noon eastern on c-span2's book tv, and sunday afternoon at 2:00 on american history tv on c-span3. the c-span cities tour working with our cable affiliates and visiting cities across the country. now a visit to the