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 25%, 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? Do you know any more? Let us know in the comments below, and don't forget to like and subscribe! While you’re at it, check out this great Alltime10s video on screen now

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