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ASTRONAUTS: WHY THE FUTURE MUST HAVE WINGS

**SPOILER ALERT** If you haven’t seen it yet, watch Astronauts:  Do You Have What It Takes?  Episode 4 on iPlayer first.

One of the tests that we were given was to present to the panel on a topic of space exploration.  Being an aerospace engineer my talk was on a topic that has fascinated me since childhood:  Access into Space.

Why The Future Must Have Wings

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The hardest part of space travel in our near solar system is getting into space in the first place; out of our atmosphere. 

So far the only way we have reached orbital spaceflight is by rockets and these, on the whole, are inefficient, expensive and unreliable.

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In comparison, aircraft are very efficient, reusable and for anyone who has flown half way across the world on holiday, incredibly affordable.

In order to understand the difference between these two technologies that have developed over a similar timeframe we really need to understand how a rocket engine works:

·       A rocket engine operates under the same principle of if release a blown up balloon.  By accelerating a large amount of gas out of the back, an equal and opposite force is imparted onto the rocket pushing it upwards, as described by Newton’s third law of motion.

·       The rocket is generating these hot, compressed gases internally through combustion.  For any combustion be it a rocket or a campfire, you need three things:  a fuel source, an oxygen source and a heat source.  The rocket carries all of these components on board with it in stored energy and as a result becomes extremely heavy.  This is evident when we see that the oxidiser is six times heavier than the fuel source!

·       But this does give it one big advantage, the rocket can operate in the vacuum of space but must result in expending it’s stages as it goes up to reduce mass.  And the atmosphere is just a hindrance.

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In comparison, the airliner doesn’t see the atmosphere as a disadvantage but uses it beneficially in three different ways:

1.     The atmosphere provides the aerodynamic lift on the wings providing the upwards force opposing gravity.

2.     Instead of carrying the oxygen with it, the jet engine uses the oxygen in our atmosphere for combustion, and

3.     Crucially the jet engines use the air as the working fluid or propellant.  The big fans and compressors, suck the air in, compress it, heat it up in the combustion chamber and accelerate it out the back creating the equal and opposite force pushing the aircraft forward.

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A much more elegant and efficient solution.  Clearly the future of space access must our atmosphere as a benefit rather than always seeing it as a hindrance.

That’s why there is a lot of interest in developing single-stage-to-orbit spaceplanes.

A spaceplane takes off and lands just like an aircraft and uses an air-breathing engine and wings to climb to the upper reaches of our atmosphere travelling at Mach 5, or five times the speed of sound.  As the air becomes too thin for the air-breathing engine, the intakes close off and it switches to a rocket engine, accelerating to Mach 25, for the last and final push into orbit.

Now imagine this, as our single stage to orbit vehicle hasn’t jettisoned it’s fuel tanks on its way to orbit, as soon as we reach orbit we have many more options open to us:  We can refuel the spaceplane with a conveniently placed orbital refuelling station giving it enough fuel to gently pop over to the moon for a supply trip or a tourism visit and after a few days it will coast back to Earth and re-enter the Earth’s atmosphere.  But the benefits don't just stop there, with the much superior re-entry characteristics the spaceplane offers it can land on one of several runways around the world and after a quick check over, a refuel, it is ready to go again.  Completely reusable.

And that is why the future must have wings.

Astronauts:  Do You Have What It Takes?  Episode 5 is on Sunday 24th September at 8pm BBC2.

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ASTRONAUTS: That Darn Rover!

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**SPOILER ALERT** If you haven’t seen it yet, watch Astronauts:  Do You Have What It Takes?  Episode 2 on iPlayer first.

It’s pretty incredible to think that we have had not one but two rovers on Mars, exploring the surface of the planet, sending us back scientific data like never before.  Both Spirit and Opportunity arrived on the red planet in 2004 and over a decade later Opportunity is still roving!  Controlling the rovers though happens at NASA but the time it takes to send a signal to Mars is an average 13 minutes.  So to send a command to the rover and for it to respond to you would take about half an hour which would be a pretty slow conversation. 

This was the premise of the test where we had to control the rover ‘Bridget’.  The scenario was that at some point in the future we may have a human crew orbiting Mars, just like the International Space Station orbits Earth.  In order to find suitable places to land or to explore before sending astronauts down it makes sense to send a rover, Bridget, to determine which places are the best.  Like NASA’s Spirit and Opportunity rovers, Bridget is also powered by batteries which are charged by solar panels.  Going into a cave is thus incredibly dangerous for a rover because if the batteries deplete whilst still in there the rover is lost forever.  On the flip side, caves are incredibly attractive if humans are to visit Mars as they would offer a natural protection against dangerous solar radiation. 

By controlling the rover from orbit around Mars instead of from Earth it would be possible to control the rovers in close to real time and that is exactly the training that UK astronaut Tim Peake did in 2016.  From the ISS in low earth orbit he controlled Bridget, on Earth, using the same setup as we had.  It is amazing to think that this was exactly what astronauts are training for (click here).

The test was to discover parts of the cave that were of most interest, as it so happened, the most interesting parts of the cave were right at the back, the farthest away from the entrance!  But also, just like in orbit, there will be a delay in the signal, making controlling Bridget somewhat difficult.  I still have my notes from our initial group briefing.

The last point was the basis of my own tactic.  Not knowing how easy it was to control with the lag in the response time and the fact that it was a very slow moving rover, 4cm per minute, I wanted to make sure there was sufficient time to get Bridget out of the cave.  As I soon found out, my strategy of finding the targets was poor but by enacting my retreat at 75% battery I overcame a moment when I really thought I would lose the rover,  and by doing the slowest three point turn in the solar system I got her out of the cave, just in the nick of time.

Everyone that sent Bridget into the cave had to change their plan to what they discovered, especially as not all of the information we were given was accurate.  Those plans that had a lot of manoeuvres suffered the most from dealing with the delayed response.  The best plans though used all of Bridget’s tools to the maximum.  It turned out that the UV light is actually quite powerful and so you didn’t need to get right to the back of the cave to spot the targets!  Both James A and Jackie figured this out quite early on and as a result did extremely well.  James A, though, didn’t even have to worry about hitting any obstacles on the way out as he just followed his own tracks back out.  Genius!

Episode 3 of ‘Astronauts:  Do You Have What It Takes?’ airs BBC 2 at 9pm on Sunday 3rd September. 

 

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ASTRONAUTS: DO YOU HAVE WHAT IT TAKES?

I must admit, as soon as I hear that word, ‘astronaut’, my ears prick up and I’m searching around for whoever said it.   I’ve always wanted to be an astronaut and I’m in awe of those that have managed to leave the confines of our atmosphere and unshackled from the bonds of gravity float freely outside of this world.
 

Source:  BBC

Source:  BBC

So when I saw an advert from the BBC requesting participants to go through a psuedo-astronaut training and selection programme run by Chris Hadfield, a 20 year veteran of NASA, I jumped at the opportunity.  It could be the closest I ever get to experience being an astronaut and here's why...

Quite literary and within the margins of error everyone that has attempted to be an astronaut fails.  Not only do you have to be in top notch physical shape (in ways that you will have no idea about), but also must have developed over the preceding decade(s) skill sets that are at the forefront of your chosen field and be ones that are of core requirement for the astronaut corp (which may change!).  That requires a lifetime of dedication, hard work and belief.  And then, you have to hope that there will be a selection process during those years when you are at your prime! 

The last ESA selection process was in 2007-8.  During that selection process nearly 10,000 highly skilled applicants from across Europe vied for six places.  The odds were pretty slim of making it into the final six and many exceptional candidates didn't.  It is the hardest selection process that exists.

But imagine achieving that dream.  It would be the ultimate adventure: Imagine seeing the Earth, the most incredible place in the known universe, from the vantage point of orbit.  Just that thought leaves me breathless.  And so, it’s always been a question I’ve asked myself, do I have what it takes to be an astronaut?  Of course, I think I do, but do the experts?  What actually do you have to have to be an astronaut? 

Fortunately I have had the opportunity to find out.  Filming this BBC series putting us through a similar selection process to a real astronaut selection process has been one of the most intense periods of my life. The other candidates are amazing.  The stress you see is real and Chris Hadfield and his team made sure it was as realistic as possible.

Episode 1 of ‘Astronauts:  Do You Have What It Takes?’ airs BBC 2 at 9pm on Sunday 20th August. 

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