To Infinity and Beyond!!

 I quite like spacey, rockety type stuff….

   ….in fact if I had to go on Mastermind, it would be the chosen subject I’d save for the grand final! Unfortunately though, I haven’t got any others for the qualifying rounds….

  2012 saw the death of iconic astronaut Neil Armstrong which was really sad. After all the heroic stuff those blokes did, you sort of expect them to be indestructible! My favourite astronaut, Pete Conrad, died a few years ago when out motorcycling with friends and Scott Crossfield, legendary X15 test pilot, died in another silly light aircraft accident in 2006.

  They’re just human after all I suppose.

  Everyone has seen and heard the black and white film of an icy cool Armstrong and Aldrin making the first moon landing – “The Eagle has landed”, “You got a bunch of guys about to turn blue here” type of thing, but my absolute favourite is the Apollo 12 landing film.

  Flown by Pete Conrad and Alan Bean, the two are mucking about all the way down, pretending they’re landing a fighter on an aircraft carrier, calling each other ‘man’, ‘baby’ and ‘dude’ etc. I always liken it to Cheech & Chong being at the controls. Conrad was famous for his frequent use of ‘colourful language’ and was under pain of death not to swear and he just manages it. Don’t know about you but if that had been me, fuck me, I’d have to have let the odd one slip out…

L to R: Conrad, Gordon, Bean

  Watch this. As a bit of background, the film starts with the LM ‘Intrepid’ still in the braking phase travelling rocket nozzle first. Bean is calling speed, attitude and altitude. He then calls ‘P64 Pete’ which is when the LM enters the ‘final approach’ phase. The LM pitches forward and Conrad gets his first decent view of the surface. His astonishment that he is coming in "Right down the middle of the road!” is obvious!

  You hear him referring to ‘L P D’, which is NASA jargon for the Landing Point Designator. This is a short window of opportunity for him to manually fine tune the final approach and landing point.

  When Bean calls ‘P66 Pete’, the LM pitches almost vertical for the final landing phase. Conrad is now fully in manual control of the spacecraft, flying it helicopter style. The rest is just ‘a-maze-ing’….

  NASA has had it’s darker moments too, in particular the Challenger and Columbia accidents. I remember the Challenger explosion really well – I’d recently started my first job after leaving school but was off sick that day. I remember lying on the settee trying to find something to watch and came across Newsround – it just happened to coincide with the launch of Challenger so they switched to Florida for a few minutes.

 “Challenger, go at throttle up…”

 BOOM.

  Just awful. Lots of lessons learned. NASA would never be that casual about shuttle missions in the future….

  In a lot of ways, the Columbia accident was a lot crueler. All the crew were doomed shortly after launch but it took fifteen days before they were killed.

  Everyone knows the story. A 'suitcase sized' lump of insulating foam broke off the main fuel tank at about Mach 2.5 shortly after lift off. It hit the leading edge of the left wing at over 500mph and punched a huge hole in a reinforced carbon-carbon panel, the shuttle’s main defence against the white hot temperatures of re-entry.

  Mission Control spotted the impact and considered it unimportant, it happened on many launches. They even briefed the crew about it, not because they were worried but just in case ‘the media asked any awkward questions about it’ during the flight. For fifteen days, Columbia’s crew were blissfully unaware that their spacecraft was fatally wounded.

  The physics and aerodynamics of a shuttle re-entry are absolutely incredible.  Hitting the outer atmosphere at around 19,000mph, Mach 25, the heating experienced is due to the rapid and extreme compression of the air encountered by the spacecraft. As Chuck Yeager once famously said, at these sorts of speeds the air simply "doesn’t have enough time to get out the way.” It’s the same effect that makes the end of your bike pump get warm after several minutes of pumping, but magnified enormously.

  The air is heated to around 1650 degrees C. Not only that, the molecules themselves are split apart to form ‘plasma’. The shuttle is engulfed in a white hot fireball during the descent but the aerodynamics and Thermal Protection System do an incredible job of keeping this energy away from the spacecraft, in fact normally less than 5% of the energy is transferred to the airframe.  The shuttle is slowly decelerated as its kinetic energy is dissipated into the surrounding atmosphere as heat and drag.

  But the shuttle isn’t one of those old style free-falling capsules, it’s actually flying while all this is going on!  Its attitude is essential for controlling heating and maintaining control and orientation. It is normally held at 40 degrees nose up by aerodynamic control surfaces and executes a series of ‘roll reversals’ rolling from about 70 degrees wing down from left to right a couple of times, again to manage lift, drag and heating.

  A hypersonic glider, roaring through white hot plasma whilst performing aerobatics! All with seven people inside. Truly amazing.

  On STS 107 though that was never going to happen. Fairly early on, the hypersonic plasma found its way into the left wing through the hole in the leading edge and slowly but surely began to melt through spas, wiring and hydraulic pipes. Mission control noticed a series of instruments going offline or giving funny readings, all located inside the left wing. Unknown to the crew, the autopilot was also noticing unusual aerodynamic effects on the left hand side – increasing drag and reducing lift – caused by the wing starting to disintegrate. Initially, it coped quite well but as the damage increased, it resorted to firing the thrusters in the nose of the spacecraft in an attempt to maintain control.

  It will never be known whether the crew noticed the unusual plasma phenomenon out the left windows or noticed the thrusters firing frantically but their first realization that something was wrong was when a ‘roll ref’ alarm message appeared in the cockpit. This was the autopilot’s way of saying “I’m at the limit of what I can do, I’m losing it…”. Seconds later, the main hydraulic lines to the aero control surfaces burnt through and the elevons and bodyflap, so essential in maintaining attitude, went limp and began flapping in the wind. At this point, the Master Alarm would have sounded.  Already in a tight left bank as part of the usual lift management procedure, Columbia pitched nose up almost vertical and wound itself into a hypersonic flat spin. Game over you might think.

  A few seconds of admirable clear thinking and heroism followed by the pilots. Faced with the horizon spinning crazily out through the windscreen and violent G forces that must have required tremendous physical effort to brace against, they diagnosed the hydraulic failure and made attempts to restart the APU’s that provided the hydraulics for the spacecraft.

  The other five crew must have been taken equally by surprise. Several hadn’t finished donning the gloves for their spacesuits, one wasn’t even seated or wearing his helmet. Over the next 40 seconds, the gyrations increased and the shuttle, no longer flying but falling, plummeted a further 60,000 ft into much denser air causing huge increases in drag and aeroheating.

  The sequence of images below is taken from NASA’s own simulation into the crew survivability aspects of the accident. Imagine the shuttle is heading towards you – it shows the nature of the oscillating flat spin the spacecraft was experiencing.

  Once the damaged left wing separates, the spacecraft begins to roll and yaw in such a way that the upper parts of the airframe are exposed to the violent dynamic loads and aeroheating. Previously shielded parts of the spacecraft are heated to 1600 degrees C within seconds. A catastrophic breakup is seconds away.

 Columbia disintegrates into three main pieces, the front including the crew compartment, the middle and the tail containing the engines.  In the cockpit, all the electrical connections would be severed and the crew would be in darkness, only able to communicate by shouting.  The crew module is a discrete pressurized vessel inside the airframe and at this point remains pressurized – the crew remain alive for the next 20 seconds or so. The front section begins to tumble wildly, subjecting the crew to increasingly violent accelerations. At some point, the pressurized crew module is breached and depressurizes instantly. It happens so quickly that not one of the crew members has time to seal their visors and pressurize their suits. For those not wearing helmets or gloves, the suits could not have pressurized anyway. At this altitude, well above the so called ‘Armstrong Limit’, the depressurization would cause massive ebullism and almost instant incapacitation – imagine a massive case of ‘The Bends’. Mercifully, the crew are now oblivious to what comes next.

  Continuing breaches of the crew module allow white hot plasma inside the cockpit, spraying molten metal onto the crew – we know this because it was found on the seat harnesses in the wreckage. The gyrations become so violent that the upper harnesses fail and the crew, just retained by their lap straps, are smashed from side to side so violently that they suffer horrific blunt trauma injuries. Apparently one helmet was recovered with human scalp and an ear in it.

  The crew module quickly disintegrates and the hypersonic blast shreds the spacesuits from the astronauts. It also rips their limbs off. Their remains are mostly incinerated by the aeroheating during the long fall to earth....

  Shocked silence…

  Horrible innit? I used to fly for a living and I’m fully aware that when doing dangerous, complicated stuff reaches the point of being ‘routine’ or even ‘boring’, you just know that you’re about to be bitten on the arse.

  Brave, talented men and women, killed by complacency.  Shocking, just shocking.

  To be fair, apart from solving the known problem of foam breaking off the main tank in the first place, there wasn’t a lot NASA could have done once the foam strike had taken place. Perhaps if they’d sent an astronaut outside for look when in orbit, they might have realised the danger. Shuttle Atlantis was in the latter stages of preparing to launch for a mission in a few weeks time and it’s been speculated that it might have been possible to hurry it up and mount a rescue mission.  That would have been another ‘Apollo 13’ moment for NASA, another ‘finest hour’.

  Failing that, it might have been possible to fly the re-entry in such a way that the damaged wing could have been spared by flying the right wing ‘into wind’. The spacecraft may have been too damaged by this to attempt a landing but it may have survived for long enough to reach a height and speed that would allow the crew to parachute to safety. We’ll never know.

  My favourite memory from 2012 are the words of Neil Armstrong’s family when asked about what could be done to honour him: 

"Next time you walk outside on a clear night and see the moon smiling down at you, think of Neil and give him a wink."

I like that.