10 Most Dangerous Space Missions Of All Time


10 Closest Calls in the History of Space Travel

10. Space Debris

At any given time, Earth is orbited by upwards of 20,000 pieces of space debris larger than a softball. That number rises to 500,000 for objects larger than a marble. They travel at speeds of tens of thousands of kilometers per hour depending on their size and can do significant damage to any spacecraft that they hit. Between 1999 and 2014, the International Space Station has had to perform 19 ‘debris avoidance maneuvers’, moving the whole station to avoid incoming debris. But this maneuver wasn’t possible on June 28th 2011, when debris approached the station at 47,000 kilometers per hour, forcing six crew members into two space capsules, ready to evacuate. If the debris made contact, the crew weren’t equipped to fix damages to the Station, and would face its depressurization if they chose to stay, which would kill them in minutes. On their closest approach, the debris came within 335 meters of the station. Luckily, the debris didn’t make contact, and the crew didn’t have to abandon the $100 billion Space Station.

9. Columbia Fuel Leak

Sadly the space shuttle Columbia is most famous for its disastrous 28th mission. However, Columbia came close to disaster 20 years earlier, and it went almost completely unnoticed. After its sixth spaceflight in 1983, Columbia landed in California and everything seemed to have gone smoothly until the next day. When technicians removed the shuttle’s rear panel they found black scorch marks caused by a leak of the shuttle’s Hydrazine fuel, which can ignite spontaneously when exposed to air. The crew hadn’t noticed the leak because it occurred in orbit and froze, but upon re-entry into the Earth’s atmosphere, the Hydrazine thawed and ignited. This thawing caused a fire and subsequent explosion, and could have spelled the end for everyone on board.

8. Solar Array Repair

On November 3rd 2007, new rooms and equipment were set to be delivered to the International Space Station, so the crew of the STS-120 unfurled the extra solar array that had been built to provide power for new extensions. The array opened smoothly to about 80% of its capacity before a jam caused an almost meter long tear in one of the panels. The crew could either open the array and risk further tears or do nothing, leaving them without enough power to install crucial extensions. Unhappy with either option, they decided to fix it themselves. They sent out their tallest astronaut, Scott Parazynski, on a 15 meter boom pole attached to the station’s robotic arm and even then were only just able to reach the tear. Parazynski was too far from the crew to be helped if anything went wrong, and surrounded by sharp metal that could easily puncture his suit and kill him. With his tools wrapped in tape to avoid electrocution, he used a contraption of wire and tape to fix the tear in a 7 hour procedure. Luckily, this was enough to support the array at full extension without tearing, and the extensions could continue.

7. Damage to the Atlantis

In 1988, just three years and two flights after the Challenger disaster, NASA almost
had another mission end in tragedy, when the Atlantis Shuttle’s solid rocket boosters
lost part of its insulation 85 seconds into launch. The insulation damaged over 700 of
the heat resistant tiles on the underside of the ship, leaving one missing completely.
These tiles are essential during re-entry, as they stop the ship from overheating.
The flight was a secret mission being carried out for the Department of Defense, so NASA
limited communication severely. For security purposes, the Atlantis crew were only allowed
to send an encrypted, low-resolution video of the ship. From this, NASA judged the extent
of the damage to be low risk, dismissing any anomalies as poor lighting.
The re-entry went ahead as scheduled despite the fact astronaut Robert Gibson saw the high
resolution video of the damage and ‘thought he was going to die’. By some miracle the
crew were fine, despite severe scorching and melted metal on the underside of the ship.
Almost 15 years later, damage to these tiles would be the cause of the Columbia disaster.

6. Solar Flares

On January 20th 2005, an X-Class Solar Flare was sent towards Earth. X-Class is the largest
classification of solar flare, and it sent the astronauts aboard the International Space
Station taking cover within the station’s most heavily insulated areas.
This precaution, which they repeated every 90 minutes for the next few days, spared them
a significant amount of radiation, reducing their exposure to about 1 rem. This is the
equivalent radiation of about one year of average exposure on Earth. This most likely
increased their lifetime risk of cancer, but it would be by less than a percent.
If the crew had been outside of the ship at the time, they would have been exposed to
50 rems. This would have increased their lifetime cancer risk by around 2.5%, as well as causing
a drop in white blood cells, likely leading to minor radiation sickness.

5. Soyuz Loses Control

In the years before NASA retired its space program in 2011, they sometimes used the Russian
Soyuz Spacecraft to ferry their astronauts to and from the International Space Station.
One of these trips took place on October 16th 2004, but upon arrival, the wrong information
was sent from the docking system to the main flight computer, causing the spacecraft to
accelerate when it was supposed to slow down.
The ship rotated to the point that the crew lost sight of the space station as they rushed
towards it. They regained manual control and were able to stop the spacecraft just over
160 feet from the station, but had they been unable to, astronaut Leroy Chiao claimed ‘we
could have collided, killed ourselves and maybe even everyone on board the station.’

4. Ballistic Reentry

The Russian Soyuz spacecraft was a source of controversy again in April of 2008, when
its re-entry capsule was bringing the first South Korean astronaut back to Earth. As a
result of last minute flight plan changes, the capsule veered off course on re-entry
and entered the atmosphere at an angle of more than 30 degrees, also known as ‘ballistic
re-entry.’
The 122,000 meter drop that followed lasted about 23 minutes, where the three astronauts
on board lost all bearing of direction and experienced forces of up to 10G. The average
person can only handle roughly half of that, meaning many will pass out on rollercoasters
which exceed 5-G.
Luckily, the crew survived the crushing gravity and had a rough ‘hit and roll’ landing
in Kazakhstan, about 480 kilometers from their intended target.

3. Friendship 7 Heat Shield

During America’s space race with Russia, the frequent shuttle launches NASA carried
out only increased the risk that one of them could end in disaster. This was almost the
case in 1962, during America’s first orbital mission.
On February 20th, a light on the Friendship 7 informed solo pilot John Glenn that the
spacecraft’s heat shield was loose. Without the resources to stay in space, Glenn had
to return to Earth, but lacked the tools to fix the heat shield and was certain to burn
up on re-entry. Strapped over the heat shield was a rocket pack for taking the ship out
of orbit, which Glenn calculated could hold on the heat shield during re-entry.
The rocket pack would typically be jettisoned on re-entry, as any remaining rocket propellant
in its tanks would explode at such heats. Luckily for Glenn, there was no fuel left
in the tanks and the rocket pack was able to keep the Friendship 7’s heat shield in
place. Glenn survived and returned home as the first American to orbit the Earth.

2. Gemini 8 Spins Out

The second near miss America experienced in the space race almost cost them the man who
arguably won it for them. The Gemini 8 mission in 1966 was the first trip to space for Neil
Armstrong, and almost his last. The mission was set to be the first time two objects docked
in orbit.
The dock was successful but soon after, boosters on each craft began to misfire, spinning each
ship out of control. Spinning at one revolution per second, both astronauts on board had blurred
vision and started losing consciousness. With seconds to spare, Armstrong shut down the
thrusters, but the lack of friction in space meant they continued to spin at the same speed.
Thinking quickly, Armstrong switched to manual control and used the ship’s backup thrusters
to counteract the spinning. This stabilized them, but cost them three quarters of the
fuel needed for re-entry. Amazingly, the reentry was successful and both astronauts went on
to walk on the moon.

1. Apollo 13

Perhaps the most famous entry on this list, Apollo 13 was intended as the third manned
mission to land on the moon, in April 1970 but that plan quickly changed when an oxygen
tank exploded two thirds of the way there.
The crew had to shut down all of the ship’s systems to conserve power, risking near freezing
temperatures of 38 degrees F, dropping oxygen levels and carbon dioxide poisoning. Having
passed the point of their first two emergency return routes, they then had to calculate
their trajectory around the moon, using its gravitational pull to send them back towards
Earth before they ran out of power, which only required the failure of one battery.
The crew of three moved to the ship’s lunar module as their lifeboat, which was designed
to house two astronauts for two days, as opposed to three astronauts for four. Drinking six
ounces of water a day and barely eating, the crew lost 50% more weight than any crew before
them. With the sacrifices on board and the calculations from ground control, the crew
were miraculously able to return to earth in the lunar module and the mission was lauded
as a ‘successful failure’ in NASA’s history.
Those were the 10 Closest Calls in the History of Space Travel, which sounded the scariest?
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