CAN WE SLOW OUR METABOLISM FOR EXTENDED SPACE TRAVEL?
It looks like we could cryo-sleep for the three month journey to Mars, but what about a twenty year voyage to the stars? That is going to require some major advances in medicine and equipment.
So, we need to consider the medical and equipment requirements for an extended cryo-hibernation at say 5 degrees Celsius. This post will focus on medical issues.
The bodies’ metabolism must be slowed to a minimum ‘ticking over’ state whilst maintaining oxygen and blood flow to all vital organs and tissues albeit at a very low rate. This will need some very clever genetically modified DNA or stem cell technology by the end of this century – we certainly don’t have it now.
But let us get Zec to describe this….
‘It is not possible to freeze someone and then thaw them out in some years’ time – the body is 65-75% water and when that turns to ice it expands – think of the damage to delicate nerve ends, capillaries. If you cool someone down, they start shivering in an attempt to generate heat and if they can’t generate enough they die of hypothermia. The key to cryo – hibernation was to cool the body very slowly and at the same time to slow the body functions so that they required very little heat to maintain life. The breakthrough in animal testing 30 years ago (around the turn of the 22nd century) was the use of new strains of genetically engineered DNA which were introduced into the body as it cooled. These controlled the slowdown of body functions, pulse, brain activity etc. and through an exothermic reaction produced minute amounts of heat right at the key points of activity. Provided that the cooling and warming periods were long enough, the infused DNA balanced the bodily rates and the amount of heat required.’
Thus the process was proved first on animals that were successfully recovered after periods of up to 5 years cryo-hibernation. They were in very good health and, surprisingly, showed no deterioration in tissue quality. They appeared not to have aged!
Proving the process on animals was a major breakthrough but how do you entice volunteers to gain confidence that cryo-hibernation works for humans and for periods of up to 20 years?
The answer may surprise you, so perhaps you would like to take a 20 year cryo-sleep to the star Seren and wake up at Cloud Planet to discover life elsewhere. But your journey through time and space is only just beginning.
Plus you will also find out who or what Zec is! Click the link below.
WATCH THIS NASA VIDEO ON HIBERNATION TO MARS
This is a relatively short duration but the principles and problems to solve are the same. Let’s now consider getting to our nearest star.
A journey to a star would mean a minimum of 20 years in the confinement of a spaceship – not impossible but a physical and mental strain for the crew – would they arrive in the right frame of mind to tackle the rigours of a new environment. Also they would be at least 20 years older, so experienced astronauts in their 30’s would already be ‘old’ on arrival. Maybe our crew would comprise of families with babies who would be young adults at the end of the journey. But this scenario is more likely for colonisation far ahead in the future.
So some form of hibernation, a method of protracted sleep, is almost certainly a must for future travel to our nearest stars. The term that springs to most people’s minds is cryo-hibernation [cryo meaning cold] but let us immediately dismiss the myth that you can freeze the human body and thaw back to life years later. Our bodies are 65% water and when that freezes it expands because ice has a lower density. The damage to sensitive cells and membranes would be traumatic. It’s a great process for preserving meats, fish etc in our freezers but in no way addresses human hibernation.
A cryo process is almost certainly the way forward as we have to slow down dramatically the bodies’ metabolism whilst maintaining a supply of oxygen to every vital organ. A hibernation temperature in the range +10 degrees Celsius to -5 degrees would be required but for the lower temperatures some form of antifreeze would have to be injected into the bloodstream which could cause complications. I consider that +5 degrees Celsius would be optimum to operate a minimal metabolism whilst maintaining tissue integrity.
There are many other issues to consider. When you wake in the morning you often feel stiff and can hardly get your eyes open! How would we cope after 20 years sleep?
I will discuss these issues in future posts and propose the technology and equipment for successful hibernation but if you want to pre-empt this then….
….board my starship in 2150 and sleep for 20 years when you will arrive at the star Seren, 10 light years away. Follow the link below.
WATCH STEPHEN HAWKING’S – ROCKET TO THE FUTURE
That was six years ago – it would be a huge ship and require an enormous quantity of fuel. But the principle is sound. In the vacuum of space you can continuously accelerate and ultimately approach a significant fraction of the speed of light.
Now there are serious plans to send a spacecraft to the stars! But on a much smaller scale, but the principle is the same.
Not big enough to take astronauts, but could the principle be scaled up?
For now let’s look at ion propulsion in more detail.
Let us imagine a journey to a star 10 light years away. We start from Mars orbit and outside the planet’s gravitational pull and use advanced rocket technology to reach Jupiter. This is a journey of 555 million kilometres [km] taking 7-8 months at 100,000 km per hour. [Approx. estimate of future capability]
We use the immense mass of Jupiter to attract and accelerate our craft onto a collision course [initially] and at the critical moment re-fire the advanced rockets to sling our spaceship around the gas giant and onto its new trajectory and new speed of 1 million km/hour.
Now we start the nuclear reactor, the only power plant capable of sustaining thrust over a 20 year journey [unless we discover something remarkable during the next 100 years]. The heat output from this reactor would be used to power a new type of drive capable of pushing our craft towards light speed. I will describe one concept which has been around for decades, surprisingly – the ion drive.
Here a stream of positively charged hydrogen ions [H+] is ejected at high speed from the rear of the object being propelled. The thrust is small but in the vacuum of space even a large object can be manoeuvred and accelerated provided you have enough thrusters. The ion drive of a starship is likely to be 50-80 metres in diameter and each of the thrusters say 5 cm round. You could get over 2 million thrusters in this drive [clustered around the advanced rockets] all contributing their power from the emitting stream of hydrogen ions.
By providing constant sufficient acceleration you would design to accelerate from 0.001c to 0.5c in 1 year [c = speed of light].
Thus our journey to a star 10 light years away would be approximately 23 years – 2 years to accelerate, 20 to get there and 1 year to slow down to a manageable speed to orbit around a target planet of our destination star.
I’m sure the mathematicians among you can calculate the acceleration required and the typical thrust needed from each tube – can we achieve this in 150 years time?
CAN WE PROPEL A STARSHIP TOWARDS LIGHT SPEED?
I think we can and in 2150 my starship leaves Mars for the star Seren, 10 light years away. You may wish to watch the event in 1972 that sparked my story.
IMAGINE THE UNIMAGINABLE!
Read all about it in my sci-fi trilogy – Quest of the Dicepterons. Follow the link below.