The Challenger crewmember remains are being transferred from 7 hearse vehicles to a MAC C-141 transport plane at the Kennedy Space Center's Shuttle Landing Facility for transport to Dover Air Force Base, Delaware. The STS-51L crew consisted of: Mission Specialist, Ellison S. Onizuka, Teacher in Space Participant Sharon Christa McAuliffe, Payload Specialist, Greg Jarvis and Mission Specialist, Judy Resnik. In the front row from left to right: Pilot Mike Smith, Commander, Dick Scobee and Mission Specialist, Ron McNair.
As we investigate the reasoning of the STS-107 breakup, we cannot ignore the horrible fate of the crew. Here is an account of the final moments of not only the Columbia, but the Challenger crew.
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Was Columbia in reentry LOS at the time of breakup?
No. Both voice communication and data telemetry were still being received right up to the breakup of Columbia. Unlike previous manned programs - Mercury, Gemini and Apollo, as well as the Russian Soyuz vehicles - the Shuttle does not have a loss-of-signal phase during reentry. The reason is actually pretty simple.
First off, understand that the blackout period is caused by a sheath of ionized air, formed during the high-heating, high-deceleration phase of re-entry, through which radio waves cannot penetrate. This is what every manned flight from Mercury thru Apollo experienced, and provided much of the suspense and drama during the reentry phase of John Glenn's Friendship 7 Mercury flight. Even the Shuttle experienced the same effect during its early flights.
The communications loss due to the blackout period was resolved after the second Tracking Data and Relay Satellite (TDRS) was placed in orbit. The reason is that the ionization sheath is open at the trailing end behind the Shuttle, providing a hole through which communication with the shuttle can be maintained with the favorably positioned TDRS. This second TDRS also allows communication during the other portions of entry that did not exist prior to its placement in 1988 - a period roughly from the time of the de-orbit OMS burn to an altitude of 200,000 feet for a landing at Edwards Air Force Base, barring passes over ground sites.
So, with two functioning TDRS satellites in operation, communications with the Shuttle can be maintained throughout the entire reentry phase of the mission.
What happened to the crew when Columbia broke up?
Actually, it's better to speculate on the fate of the crew cabin, and then decide for yourself what probably happened to the crew.
Once the cabin tore loose from the rest of the fuselage and all electrical power was lost, the cabin was probably hammered, buffeted and braked by atmospheric drag as it continued its re-entry. The cabin would have been heated by the surrounding shock-induced plasma, and as G-forces built up the integrity of the heat-weakened aluminum infrastructure would have been compromised and the cabin would eventually collapse in on itself. Some fragmentation would have no doubt taken place, and pieces would have broken loose and fallen behind and below the cabin's path as they slowed down quicker in the atmospheric drag.
This speculation is based on some of the findings of the investigation into the loss of Challenger in 1986. As with Columbia, the initial impressions on the fate of the Challenger crew was that they had perished instantly when the shuttle came apart a minute after launch. However, when the crew cabin was found relatively intact a few months later did it become apparent that the cabin had in fact separated cleanly from the fuselage, continued on a parabolic arc to an altitude of ~65,000 feet, and then fell back to impact in the Atlantic Ocean with a force of 200 G’s. Even then, the cabin was still relatively intact despite hitting the surface of the ocean with that degree of force.
When the cabin broke loose from the rest of Challenger, it became separated from all electrical and life support resources. Save for a few seconds of air in the lines, very shortly after separation the crew would have been without any life support. Upon recovery it was found that the state of some life-support equipment indicated that at least some of the crew had survived the initial breakup were able to activate their safety equipment. Three of the four Personal Egress Air Packs (PEAP) located behind each seat on the Shuttle had in fact been activated. However, because the crew were not wearing any sort of pressure suits, the PEAPs would not have provided the required amount of breathable air necessary to retain consciousness at the altitudes the cabin reached. The team of coroners and medical specialists that performed the autopsies of the remains concluded that that the crew were soon all unconscious shortly after the cabin began its final arc of transit, and were most likely not killed until the impact with the ocean, two minutes after the External Tank exploded.
It should be noted that since the loss of Challenger, many of the contingency plans were revised extensively. As a result, Columbia’s crew were equipped with better survival gear, including pressure suits and personal parachutes. Assuming they were conscious of the emergency, the Columbia crew would have closed their visors when cabin pressure was lost, which would have automatically pressurized the suits. At that point, the only thing the crew would have needed to do would have been to wait until the cabin fell below 15,000', blow the escape hatch, extend the egress pole, slide out and away from the orbiter down the pole, and parachute to safety. This is how the procedure works in theory, and provided the cabin stayed relatively intact until 15,000'. Since this did not happen, it can be assumed that the cabin was compromised in such a way that the crew had no opportunity to attempt any sort of egress.
In Hemphill, searchers found what are believed to be human remains, and what appeared to be gauges and other Columbia components in a farmer's field on 2/10/03. Although no details were given on the human remains, over 100 pieces of debris ranging from gauges to switches and other components, many of which still had the wires attached to them. Remains that a hospital employee identified as charred torso, thigh bone and skull on a rural road near other unspecified debris in Hemphill, east of Nacogdoches. Remains identified as a charred human leg on a farm in Sabine County, about 50 miles (80 km) east of Nacogdoches.
"Elsewhere around Norwood, even grimmer discoveries were being made. Deputy Faron Howell was in charge of search teams that soon began stumbling across human remains.
"There was a hand, and a foot, then a leg from the knee down. One of my men found a human heart. The biggest piece was a torso, the upper bit with the chest ripped in half." A thigh bone and a skull, the flesh torn away, were also located."
The Unthinkable Fate of the Challenger Crew
The last words captured by the fight voice recorder in Challenger were not Commander Francis Scobee's haunting, "Go at throttle up." Three seconds later, Pilot Michael Smith uttered, "Uh oh," at the very moment that all electronic data from the spacecraft was lost.
The public has never heard the inflection of Smith's words, nor the ambient noise in the cabin that underscored them (you can read a transcript here). Despite the existence of evidence of what happened after Challenger's 73 seconds of flight, little of that reality is part of the public's consciousness, understanding, or recollection of the events of January 28, 1986. In part, this can be attributed to a justifiable desire to believe in a merciful outcome: that Christa McAuliffe and the shuttle astronauts all died instantly in what appeared from the ground to be an explosion. But like Smith's instinctive interjection, telltale signs exist that our worst nightmare about the Challenger disaster may have been true. It was very likely that the mid-air blast was not strong enough to kill the crew - and that at least some of the seven astronauts were terrifyingly aware of the impending fate.
More about Challenger
On July 28, 1986, Dr. Joseph P. Kerwin, director of Life Sciences at the Johnson Space Center, submitted his report on the cause of death of the Challenger astronauts. The crew module was found that March in 100 feet of water, about 18 miles from the launch site in a location coded "contact 67." While references to the crew were stricken from the report, details about the condition of the module provide many clues about the fate of the astronauts. Kerwin wrote that the cause of the crew's death was inconclusive, but that the force of the initial explosion was too weak to have caused death or even serious injury. This was a direct contradiction to NASA's standard line about the crew's fate, that they were vaporized in the explosion and suffered no further.
If the astronauts were not killed by the blast, then how long did they survive? Challenger as a whole was destroyed at 48,000 feet, but the crew module continued its flight upward for 25 more seconds (to 65,000 feet) before pitching straight down and falling into the Atlantic Ocean.
Evidence that at least some of the crew survived included the recovered personal egress air packs, or PEAPs, designed to provide oxygen to the crew in case they had to ditch the craft in a ground emergency. (NASA had no protocol for in-flight shuttle emergencies in 1986.) Each pack contained several minutes of breathing air, but the tanks had to be opened manually. Salvagers recovered four PEAPs; three of them had been opened. The one belonging to Michael Smith was mounted behind his seat, so it's likely another crewmember had leaned forward to activate it.
Kerwin and his experts theorized that the loss of cabin pressure inside the module could have knocked out the crew within a matter of seconds, but damage from the 200-mph impact made determining the rate of depressurization impossible. The air from the PEAPs would not be enough to keep the crew conscious during a rapid drop in pressure. But a rapid drop in pressure would likely have ripped up the middeck floor, which did not occur. A slow or gradual drop in pressure would keep the crew conscious much longer, and the impact at the bottom of that tumble was harsher on the crew's bodies than any car or plane crash would have been.
In either scenario, it is likely that some - if not all - of the crew were awake and coherent after the disintegration of Challenger, and were conscious long enough to feel the module pitch its nose straight down, to see the blue sky in the cockpit window rotate away in favor of the continent below, and to experience a weightless free fall toward the ocean that lasted a full two minutes and 55 seconds. It is a horrifying scenario so extreme that it's unlikely that even 25 more years will be enough to contemplate it objectively.
For now, many still choose to believe that the men and women aboard the Challenger didn't survive the explosion and were unaware that their loved ones on the ground were watching them descend in a plume of smoke to their deaths. Perhaps that belief holds some truth. Or perhaps, it simply serves to bring some peace to the earthbound souls left in the wake of the Challenger's loss.
Challenger was one of NASA's greatest successes - but also one of its darkest legacies.
It was initially built between 1975 and 1978 to be a test vehicle, but was later converted into a fully fledged spacecraft.
In its heyday, it completed nine milestone missions - from launching the first female astronaut into space to taking part in the first repair of a satellite by an astronaut.
But it was also the vehicle that very nearly ended the space program when a probe into the 1986 disaster found that the shuttle was doomed before it had even taken off.
Roger Boisjoly, a NASA contractor at rocket-builder Morton Thiokol Inc, warned in 1985 that seals on the booster rocket joints could fail in freezing temperatures.
'The result would be a catastrophe of the highest order — loss of human life,' he wrote in a memo.
On the eve of the ill-fated flight, Boisjoly and several colleagues reiterated their concerns and argued against launching because of predicted cold weather at the Kennedy Space Center.
But they were overruled by Morton Thiokol managers, who gave NASA the green light.
After the accident, Boisjoly testified to a presidential commission investigating the Challenger accident.
The group determined that hot gases leaked through a joint in one of the booster rockets shortly after blastoff that ended with the explosion of the shuttle's hydrogen fuel.
Boisjoly died in 2012 aged 73.
HOW CREW DIED ACCORDING TO NASA STUDY
(The following information appeared on the NASA Headquarters Website.)
On July 28, 1986 Rear Admiral Richard H. Truly, NASA's Associate Administrator for Space Flight and a former astronaut, released this report from Joseph P. Kerwin, biomedical specialist from the Johnson Space Center in Houston, Texas, relating to the deaths of the astronauts in the Challenger accident. Dr. Kerwin had been commissioned to undertake this study soon after the accident on January 28, 1986. A copy of this report is available in the NASA Historical Reference Collection, History Office, NASA Headquarters, Washington, DC.]
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RADM Richard H. Truly
Associate Administrator for Space Flight
NASA Headquarters
Code M
Washington, DC 20546
Dear Admiral Truly:
The search for wreckage of the Challenger crew cabin has been completed. A team of engineers and scientists has analyzed the wreckage and all other available evidence in an attempt to determine the cause of death of the Challenger crew. This letter is to report to you on the results of this effort. The findings are inconclusive. The impact of the crew compartment with the ocean surface was so violent that evidence of damage occurring in the seconds which followed the explosion was masked. Our final conclusions are:
·the cause of death of the Challenger astronauts cannot be positively determined;
·the forces to which the crew were exposed during Orbiter breakup were probably not sufficient to cause death or serious injury; and
·the crew possibly, but not certainly, lost consciousness in the seconds following Orbiter breakup due to in-flight loss of crew module pressure.
Our inspection and analyses revealed certain facts which support the above conclusions, and these are related below: The forces on the Orbiter at breakup were probably too low to cause death or serious injury to the crew but were sufficient to separate the crew compartment from the forward fuselage, cargo bay, nose cone, and forward reaction control compartment. The forces applied to the Orbiter to cause such destruction clearly exceed its design limits. The data available to estimate the magnitude and direction of these forces included ground photographs and measurements from onboard accelerometers, which were lost two-tenths of a second after vehicle breakup.
Two independent assessments of these data produced very similar estimates. The largest acceleration pulse occurred as the Orbiter forward fuselage separated and was rapidly pushed away from the external tank. It then pitched nose-down and was decelerated rapidly by aerodynamic forces. There are uncertainties in our analysis; the actual breakup is not visible on photographs because the Orbiter was hidden by the gaseous cloud surrounding the external tank. The range of most probable maximum accelerations is from 12 to 20 G's in the vertical axis. These accelerations were quite brief. In two seconds, they were below four G's; in less than ten seconds, the crew compartment was essentially in free fall. Medical analysis indicates that these accelerations are survivable, and that the probability of major injury to crew members is low.
After vehicle breakup, the crew compartment continued its upward trajectory, peaking at an altitude of 65,000 feet approximately 25 seconds after breakup. It then descended striking the ocean surface about two minutes and forty-five seconds after breakup at a velocity of about 207 miles per hour. The forces imposed by this impact approximated 200 G's, far in excess of the structural limits of the crew compartment or crew survivability levels.
The separation of the crew compartment deprived the crew of Orbiter-supplied oxygen, except for a few seconds supply in the lines. Each crew member's helmet was also connected to a personal egress air pack (PEAP) containing an emergency supply of breathing air (not oxygen) for ground egress emergencies, which must be manually activated to be available. Four PEAP's were recovered, and there is evidence that three had been activated. The nonactivated PEAP was identified as the Commander's, one of the others as the Pilot's, and the remaining ones could not be associated with any crew member. The evidence indicates that the PEAP's were not activated due to water impact.
It is possible, but not certain, that the crew lost consciousness due to an in-flight loss of crew module pressure. Data to support this is:
·The accident happened at 48,000 feet, and the crew cabin was at that altitude or higher for almost a minute. At that altitude, without an oxygen supply, loss of cabin pressure would have caused rapid loss of consciousness and it would not have been regained before water impact.
·PEAP activation could have been an instinctive response to unexpected loss of cabin pressure.
·If a leak developed in the crew compartment as a result of structural damage during or after breakup (even if the PEAP's had been activated), the breathing air available would not have prevented rapid loss of consciousness.
·The crew seats and restraint harnesses showed patterns of failure which demonstrates that all the seats were in place and occupied at water impact with all harnesses locked. This would likely be the case had rapid loss of consciousness occurred, but it does not constitute proof.
Much of our effort was expended attempting to determine whether a loss of cabin pressure occurred. We examined the wreckage carefully, including the crew module attach points to the fuselage, the crew seats, the pressure shell, the flight deck and middeck floors, and feedthroughs for electrical and plumbing connections. The windows were examined and fragments of glass analyzed chemically and microscopically. Some items of equipment stowed in lockers showed damage that might have occurred due to decompression; we experimentally decompressed similar items without conclusive results.
Impact damage to the windows was so extreme that the presence or absence of in-flight breakage could not be determined. The estimated breakup forces would not in themselves have broken the windows. A broken window due to flying debris remains a possibility; there was a piece of debris imbedded in the frame between two of the forward windows. We could not positively identify the origin of the debris or establish whether the event occurred in flight or at water impact. The same statement is true of the other crew compartment structure. Impact damage was so severe that no positive evidence for or against in-flight pressure loss could be found.
Finally, the skilled and dedicated efforts of the team from the Armed Forces Institute of Pathology, and their expert consultants, could not determine whether in-flight lack of oxygen occurred, nor could they determine the cause of death.
/signed/
Joseph P. Kerwin
"Exactly what happened..."
In February 2001 a visitor to my "Icarus Rising" site asked if I could tell her "exactly what happened" in the Challenger disaster. After chuckling for a moment over the fact that whole books have been written on that topic, I sat down and typed out for her the following summary of events, which is based upon my examination of print and video records of the disaster.
The extreme cold of the night before had chilled the rubber insulating O-rings in the right solid rocket booster's aft field joint (the joint near the SRB's lower supporting strut that attached it to the external fuel tank) well below their specified operating temperature. Because no shuttle had ever been launched in such cold weather, engineers at Morton Thiokol (the company that manufactures the boosters) had no data to say just what would happen in such conditions, although their examination of retrieved boosters from previous launches had led them to conclude that lower launch temperatures directly affected the O-rings' ability to seal the joints properly upon SRB ignition. This sealing failure was called "blow-by" and was indicated by evidence of hot gases from the firing of the SRBs having eroded the O-rings during flight. The lower the temperature, the greater the blow-by. In fact, one SRB used on a 1983 Challenger launch had actually sustained a complete O-ring failure resulting in hot gases escaping from the joint, but the moment of failure had occurred after the SRBs had separated from the external tank. If it had happened half a minute or so earlier, we would today be talking about the 1983 Challenger disaster. Nevertheless, Morton Thiokol engineers could not categorically say that the seal would fail if the shuttle were launched in sub-freezing temperatures, only that it might, and so their "no-go" recommendation was overruled by Morton Thiokol managers, who in turn gave the "go" to NASA managers. In fairness to those who approved the launch, evidence of "blow-by" had been observed during launches when the air temperature was as high as 73 degrees, and they argued that "blow-by" appeared to happen no matter what the temperature was (of course, this should have been taken as evidence that the entire O-ring and joint configuration needed to be redesigned anyway).
When the SRBs were ignited at liftoff on January 28, both the primary and the secondary O-rings at the right SRB's aft field joint failed as engineers had feared they would. Evidence of this failure took the form of high-speed video images that showed seven discrete puffs of dark black smoke emanating from the area of the right SRB's aft field joint during the first two seconds after liftoff. However, the leak apparently sealed itself after that, probably plugged by debris from burned fuel and the failed O-ring seals.
This temporary plug appeared to stay in place for the next 56 seconds until the shuttle entered the zone of maximum dynamic pressure, called Max Q, during which shuttles ordinarily experience increased atmospheric stress as they climb toward orbit (later data showed that the stress Challenger endured that day was greater than on any previous launch but still within design specifications). At 58 seconds after launch, however, long-range video showed a flicker appearing in the area of the right SRB's aft field joint and quickly expanding to a continuous plume of flame; the stress of going through Max Q coupled with the throttling up of the shuttle's main engines apparently had broken the debris plug at the joint, allowing a 6,000 degree flame to escape through the side of the booster. The slip stream caused by the shuttle's nearly 1,500 mile-per-hour speed deflected the plume toward the SRB's lower supporting strut and the external fuel tank. The increasing loss of chamber pressure in the right SRB due to the leak caused the shuttle's guidance system to compensate for the loss of thrust on the right side by swiveling the shuttle's engines and the SRBs' nozzles in an attempt to keep Challenger on course. At 66 seconds after liftoff, data showed a significant loss of fuel pressure from the external tank to the main engines, indicating a growing hydrogen fuel leak, which fed the growing flame from the right SRB's failed joint. By this time the SRB's supporting strut had been severely weakened by exposure to the flame, as had the surface of the external tank. At 70 seconds after liftoff, long-range video showed a circumferential leak of hydrogen gas about a third of the way up on the external tank, indicating that the hydrogen innertank had failed. A bright, sustained glow also appeared between the external tank and the underside of the shuttle. At 72 seconds, data showed extreme movement of the right SRB relative to the left booster and the shuttle, indicating that the lower supporting strut had broken away completely.
At this point several simultaneous events occurred that resulted in the destruction of the shuttle. Probably at the same time that the SRB supporting strut failed, the lower third of the external tank fell away, releasing the hydrogen innertank's remaining load of liquid hydrogen. This release propelled the upper part of the hydrogen innertank upward into the liquid oxygen tank above it. At about the same moment, the right SRB pivoted around its remaining upper strut, its nose cone smashing into the top of the external tank. This resulted in the release of all of the remaining liquid hydrogen and oxygen fuel, which vaporized instantly in the thin atmosphere nine miles up. This sudden fuel vaporization produced what appeared to be a fireball or fiery explosion but was really a combination of reflected sunlight, radiance from the brightness of the SRBs' exhaust nozzles and some local burning of gases within the expanding vapor cloud. Because of the right SRB's pivoting around its upper attachment, its motion suddenly pointed Challenger to the left, with the result that the shuttle was no longer pointed in the same direction that it was flying. The resulting aerodynamic stress from this "broadside" effect at nearly 2,000 miles per hour was more than the shuttle was built to withstand, and the forward part of the shuttle broke away from the payload bay. The nose of the shuttle became separated from the crew cabin, the steering rockets in the nose releasing their fuel in an explosive burn. The rest of the shuttle, its forward end suddenly opened like a tube to the supersonic wind, blew apart from the inside out. All of this happened within the space of a second or so. Contrary to initial speculation, there was no actual explosion (in spite of Tom Brokaw's citing of scientists at the time who likened the force of the "explosion" to that of "a small nuclear blast"); what we saw was the dramatic vaporization of Challenger's liquid fuel in the thin atmosphere as the shuttle broke up under severe aerodynamic stress. Challenger was not blasted to pieces by an explosion; it was blown apart by aerodynamics.
The crew cabin's momentum after the breakup quickly carried it upward to an altitude of around twelve miles before aerodynamics and gravity slowed its ascent and the cabin began the long fall to the ocean. What happened to the crew after the breakup and during the fall will never be fully answered. When the cabin broke away from the rest of the shuttle, it lost all its electrical power and oxygen supplies. If the cabin depressurized due to the breakup, then the crew would have quickly begun losing consciousness due to lack of oxygen. The fact that three out of four recovered PEAPs (Personal Egress Air Packs) had been activated and partially used indicates that at least some of the crew survived the breakup long enough to take some action to try to stay alive. Their having turned on the PEAPs does not prove that the cabin lost pressure but does show that at least some of the crew, all of whom were wearing air-tight flight helmets, believed that pressure had been lost or was being lost (otherwise, the packs wouldn't have been activated). If the cabin indeed lost pressure after the breakup, then the crew in all likelihood lost consciousness, although the short time between breakup and the cabin's impact with the ocean means that, barring cardiac arrest, they were alive but unconscious when the cabin hit the water. If, on the other hand, the cabin maintained its pressure, then they were likely alive and awake until the end. A third possibility is that the cabin depressurized at the altitude of shuttle breakup but repressurized as it fell into the denser atmosphere near sea level, which raises the nightmarish possibility that the astronauts passed out after the breakup only to regain consciousness in time to see the ocean's surface racing toward them at 200 miles per hour. Regardless of whether they were conscious or unconscious during the fall, any astronauts still alive died instantly upon impact with the ocean's surface. Damage to the cabin from its hitting the ocean's surface made it impossible to determine what damage, if any, had happened to the cabin during the breakup, which is why it's impossible to say just what happened to the crew during the fall. (The alleged "transcript" of the crew's fall to the ocean that has been published in tabloid magazines and on some Internet sites is only a hoax.)
