It was April 19, 1971. The Soviet Union had just launched the world’s
first space station into low Earth orbit, named Salyut-1 [Sal-yoot]. Two months later, on June 6, 1971, the Soyuz
11 [Soy-ooz] would make a trip to the orbiting space station with cosmonauts Georgi Dobrovolski,[Ghee-ohr-ghee
Dough-bro-vole-skee] Vladislav Volkov [Vol-cove], and Viktor Patsayev [Pat-sigh-yev] aboard
the spacecraft. The Soyuz 11 launched into space, and the
three cosmonauts boarded the Salyut-1 space station on June 7, 1971, without any trouble,
and were there to carry out three weeks of experiments, such as growing Chinese cabbage
and bulb onions, taking spectrograms of stars, and snapping some ‘from orbit’ photos
of the snow and ice on the River Volga. They were now heroes, famous, and plastered
all over Soviet evening television. On June 29th, 1971, with the cosmonaut's primary
mission complete, the Soyuz 11 finally undocked from the Salyut-1, and three hours later,
the spacemen fired their ship’s engine to return to Earth. Vladislav Volkov joked with flight control
and asked them to make sure their traditional welcome-home gift of cognac would be waiting
for them at the landing site. At twenty-nine minutes before touchdown, and
at an altitude of 160 kilometers [100 miles], explosive charges fired as planned to separate
the Soyuz 11’s orbital bell-shaped capsule and instrument modules. The space capsule was now the cosmonaut's
only defense against the fiery furnace of re-entry. But then something unexpected happened… As soon as the other modules were jettisoned,
the pressure inside the crew capsule quickly fell, and all the air inside began escaping
into the vacuum of space. Meanwhile, mission control was unaware of
the situation. Attempts to contact the cosmonauts over VHF
radio were met with an unnerving silence, and a sense of nervous unease crept into the
room. Twenty-two minutes before touchdown, the capsule
was picked up on radar entering Soviet airspace. Mission controllers knew that because the
spacecraft was still re-entering the atmosphere, it would be covered in a cocoon of plasma,
and therefore communication would be impossible during this time. As the minutes went by, hopes for a happy
ending were rekindled when the space capsule’s drogue parachute automatically deployed, and
then the larger main parachute canopy followed. However, there was still no word from the
crew, and ten minutes before touchdown, helicopter crews spotted the undamaged Soyuz 11 gently
swinging back and forth under the perfect looking parachute. Mission control was elated when the helicopter
commander radioed that the capsule had landed safely. The recovery team was setting down nearby,
and they were just minutes from opening the hatch and treating the cosmonauts to their
cognac and other comforts of home after being in space for three long weeks. Within just two minutes of touchdown, the
search and rescue team of two men reached the Soyuz 11, and then hammered on the ship’s
hull to let them know they were there. But there was no reply from inside… When they opened the hatch, a look of troubled
uncertainty creased the face of one of the rescuers. Inside the capsule, the recovery team saw
all three cosmonauts slumped over and motionless. Their faces were covered with dark spots that
looked like bruises, and blood was coming from their noses and ears. One of the spacemen, Dobrovolski, was still
warm, but attempts to revive him were unsuccessful. The first contact between the recovery crew
and mission control took the form of three numbers: 1-1-1. This was a code that represented the health
of the cosmonauts. The number 5 stood for excellent condition,
4 was good condition, 3 meant there were injuries, 2 meant they were seriously injured, and 1
meant the injuries were fatal. So what happened? Based on the positions of the three cosmonauts’
bodies upon their discovery, investigators came to the conclusion that Dobrovolski and
Volkov had unstrapped themselves from their seats to try to find the leak that was allowing
air to escape from the capsule. Health trackers showed their heart rates soared
as they searched. But time was not on their side, as within
just 50 seconds, Patsayev’s pulse dropped as his body became starved for oxygen, and
within 110 seconds, all three cosmonauts had perished. Investigators had learned that a faulty valve
was the cause of the space accident. Their funeral was epic on a grand scale, and
the whole country mourned their passing. The Soviets halted all human spaceflights,
while engineers redesigned the Soyuz spacecraft. All cosmonauts are now required to wear spacesuits
during launches and landings. But Russia is not the only country to have
a space disaster that cost the lives of brave astronauts. The United States was leading the world in
space travel with the ingenious engineering of the reusable Space Shuttle. But even the most advanced spacecraft can
have problems. By January 1986, the United States seemed
bored with spaceflight since the first space shuttle launch on April 12, 1981, and Americans
were already used to the sight of the space shuttle launching. The program had experienced no trouble since
its debut flight. But everything would quickly change. On the morning of January 28, 1986, the crew
of mission STS-51L boarded the orbiter Challenger. It was a sunny, but chilly Tuesday morning. All across the USA, people were a little more
excited with this launch, because the crew of seven astronauts included payload specialist
Christa McAuliffe, who was a civilian, school teacher, and mother of two children. She was part of the ‘Teacher in Space’
project, and proof that space was now wide open, not just to top gun fighter pilots,
but also the average American. The Challenger shuttle was commanded by Dick
Scobee with Michael Smith as the pilot, along with mission specialists Ellison Onizuka,
Judith Resnik, and Ronald McNair. The other payload specialist with Christa
McAuliffe was Gregory Jarvis. At 11:38 a.m., the space shuttle Challenger
lifted off from Cape Canaveral, Florida, with Christa McAullife on her way to becoming the
first ordinary American to travel into space. But after just 73 seconds, and with hundreds
of people on the ground watching, including Christa’s family and a group of students,
plus millions of viewers watching the launch on television, the space shuttle exploded
into a ball of fire and smoke and disintegrated. So what happened? We mentioned it was a cold morning. In fact, there was ice on the tower two hours
before the launch. An overnight measurement taken by the ice
team recorded temperatures on the left solid rocket booster at -4 degrees Celsius [25 °F]
and the right SRB was -13 degrees Celsius [8 °F]. However, these measurements were recorded
for engineering data only and not reported, as the temperatures of the solid rocket boosters
were not part of the Launch Commit Criteria. Before we go on, it’s important to know
that the shuttle solid rocket boosters are made up of four segments bolted together at
three O-ring joints. These O-rings are in place to maintain internal
pressure of the SRB, and any failure of these O-rings would create a ‘burn through’,
causing a catastrophic failure. This is exactly what happened to the right
solid rocket booster. There was a puff of black smoke from the right
SRB at liftoff, showing that the O-ring had already failed. By the time the shuttle was in the air, flames
started to come from the failed O-ring, and the sideways flame cut through the SRB like
a cutting torch. The 1.2 billion dollar spacecraft, its satellite
payload, and the seven astronauts were lost instantly. The biggest factor in the accident was the
cold. The launch itself was performed in -3 degrees
Celsius [26 °F] weather, and engineers knew of the dangers posed to the O-rings at such
low temperatures. However, despite the many warnings from engineers,
the shuttle was cleared for launch. NASA shut down the space shuttle program for
two years after this terrible tragedy, as its engineers redesigned many components of
the shuttle. But it would not be the last space shuttle
disaster. The Space Shuttle Columbia was the first shuttle
to be launched into space in April 1981. The shuttle launched again twenty-seven more
times after its maiden voyage, and on January 16, 2003 it was on its 28th flight. The seven member crew of mission STS-107 were
mission commander Rick D. Husband, pilot William C. McCool, payload commander Michael P. Anderson,
Israeli astronaut Ilan Ramon [Elon Ra-moan] serving as payload specialist, flight engineer
Kalpana Chawla who had previously flown on mission STS-87, and U.S. Navy captains flying
as mission specialists’ David M. Brown and Laurel Blair Salton Clark. The launch seemed to go well and without problems. The astronauts were on a 16-day mission, and
successfully conducted around 80 science and research experiments, working 24 hours a day
in two alternating shifts. It was now time for the crew to return home,
and the space shuttle Columbia was scheduled to reenter the atmosphere and land on February
1, 2003. At 2:30 am Eastern Standard Time, the Entry
Flight Control Team started its shift at Mission Control. Aboard the orbiter, the crew put away loose
items and prepared for re-entry. Husband and McCool began working through the
entry checklist. And at 1:10 pm, the Columbia crew was approved
to conduct their deorbit burn, which lasted 2 minutes and 38 seconds. At 1:44 pm, Columbia reentered the atmosphere
at an altitude of 120 kilometers [400,000 feet] Four and a half minutes later, a sensor
began recording a greater than normal amount of stress on the left wing. But the sensor's data was sent to an internal
recorder, and the crew or ground controllers didn’t see it. The orbiter began to yaw to the left because
of the increased drag. However, the orbiter's flight control system
corrected the problem, and the crew never noticed the drag, or what was happening. This was followed by sensors indicating problems
in the left wing hydraulic systems, and a loss of tire pressure on the left side landing
gear. Columbia was flying at 60 kilometers [38 miles]
above Earth at a speed of 20,120 kilometers per hour [12.500 mph] when flight controllers
received their last communications from the shuttle. Video from many witnesses watched in horror
as the orbiter broke up and disintegrated. So what happened to Columbia and its crew? NASA’s Intercenter Photo Working Group was
looking over videos of the launch after Columbia entered orbit as a routine review. It wasn’t until the second day that they
discovered a piece of foam had broken off from the large external tank and impacted
the left wing as the shuttle was climbing into orbit. The Debris Management Team was unable to determine
the damage caused to the left wing, and multiple requests for images were made to the US Department
of Defense. A request was relayed to the US Strategic
Command, which began identifying assets that could snap images of the orbiter. However, the image request was denied by NASA
Mission Management Team Chair Linda Ham after she discovered where the request came from. She asked a flight director about the imaging
requirement, but not the Debris Assessment Team. Moving the orbiter into a position to be imaged
would have disrupted ongoing science operations, and Ham dismissed the Department of Defense's
imaging capabilities as insufficient to assess damage to Columbia’s left wing. Now here is where things get more interesting. Mission management downplayed the risk of
the debris strike in communications with the Columbia crew, and flight director Steve Stich
sent an email to Husband and McCool telling them of the strike and that there was no concern
about damage since foam strikes occurred on previous flights. They also got a 15-second video of the debris
strike, but were reassured there was no danger. Obviously, they were wrong. No one knows the true extent of the damage
to the wing, but members of the Columbia Accident Investigation Board performed a test using
a space shuttle wing part, and fired a chunk of foam at high speed at the same spot a chunk
of foam hit Columbia’s wing…and this is what happened. To the amazement of onlookers, the investigators
blew a gaping 60-centimeter [2 foot] gaping hole in the shuttle wing after firing a chunk
of foam insulation at it. This was the smoking gun that proved that
the damage from the debris strike led to Columbia’s destruction, and the loss of her crew. It was the last space shuttle launch, and
the space shuttle program was permanently retired after this. Since then, astronauts have been getting into
space with Russia’s Soyuz program, and now SpaceX’s rockets. That’s all the time we have for now. We hope you found the video interesting, and
learned how brave our men and women who go into space are. Stay tuned here for more incredible space
stuff, and thank you for watching.
