Flights into the Future Pt. 01: Through Space to the Moon.

In this interesting, informative and up-to-the-minute "quiz," the distinguished science Professor A.M. Low, a former President of the Interplanetary Society, asks and answers exciting questions that have been growing in the minds of people ever since the war showed the possibilities of rocket flight, and the release of atomic energy gave new impulse and power to science.

Will men now be able to fly out through space to the planets?  If so, how - and when?

Question:  Do you think that a journey to another world is now possible?

Answer:   I suspect the "now" in your question means that there has been talk of journeys to the moon, or even further, for years, and you are wondering when action is going to talk the place of talk!  Will astronautics always be a pure theory, or is it now entering a period of practice?

I remember arguments before World War I about whether transatlantic flights and regular passenger services by air between America and England would become possible.  Most people looked on us as rather wild speculators who ought to be writing science-fiction instead of talking about transatlantic mail services as if they would really happen!  Even H.G. Wells, who never lacked daring, at the end of the last century would not commit himself beyond saying that by the fourth decade of the twentieth century - that is, between 1940 and 1949 - man would have actually risen from the ground in a heavier-than-air machine and make a safe landing!  And Wells was one of the greatest men who ever lived!

But in astronautics, perhaps fiction has run a little ahead of fact.  We have had scores of stories of journeys to Mars and Venus even before a single human being has flown in a rocket.  We have not yet solved all the problems of a journey to another world, but we have come so close to doing so that any day now we may have the designs for a practical rocket that would reach, say, the moon.  In fact there have already been several "blue-prints" for moon-rockets that are satisfactory, at least on paper.

Question: Then why hasn't someone started to build a space-ship?

Answer: The "blue-prints" called for several things we haven't got - a fuel for the rocket motors that is in every way suitable; but, perhaps even more important, about £20,000,000, which the blue-print drawers certainly haven't got!

These temporary obstacles.  I believe that in the next decade the first steps will be taken in practical astronautics, and that within twenty years men may have attempted journeys outside the earth's field of gravity.  I don't think I am being rash in predicting that there are people alive today who will land on the moon before they are dead or who will certainly talk to men who have landed on the moon.

Question: You speak of "rockets".  Is ti essential for a space-ship to be a rocket?

Answer: In the light of our present knowledge, only a rocket could get outside the earth's field gravity.  The alternative method of propulsion by a propeller is no good, because even ten miles up there would not be enough air for the propeller or airscrew to get a grip.  Even a normal jet plane would not do, since it depends upon taking in air, and there is no air in space.

Question: If there is no air, how could a rocket propel itself?

Answer: A rocket moves quite independently of its surroundings.  It pushes forward, not against the air, as is so often supposed, but because of the stream of gases it emits.  A rocket moves forward for the same reason that a gun moves backwards, or recoils, when fired.  If you fired a machine-gun on a smooth surface it would proceed backwards in a series of little jerks.  You could test the fact that it move equally well in a vacuum by firing a revolver containing a blank cartridge in an exhausted bell jar.  The revolver would jerk backwards just the same as if it were fired in air.

The scientist says that a rocket moves forward forward by "reaction" in accordance with Newton's third law of motion.  Its motion depends upon the mass of the gases ejected, and their velocity.  This fact enables rocket experts to calculate very exactly what will be the speed of different rockets burning different fuels in different ways.  It isn't necessary actually to fire the rocket.  The work done, referring to your first question, has not been so theoretical as it seems, and many rockets have been practically tested "on the bench" and in wind-tunnels, just like aircraft engines.

Because there is less air resistance in front and behind, a rocket actually works more efficiently in a vacuum than in air.  The lack of air in front means less friction and behind less resistance to the stream of gases being ejected.

Question: I have often seen it stated that Jules Verne's projectile in From Earth to Moon could never have been built and would not work.  Is this true?

Answer: Yes.  Quite apart from the fact that the occupants of the projectile would had been squashed like flies against one end of the projectile at the moment of firing and then squashed again at the the other end as the projectile emerged from the cannon, calculations on paper show that no cannon, even if its barrel were more than 1,000 feet long, could throw a projectile beyond the earth's sphere of gravity.  There are other objections, notably the one that the initial speed of a projectile fired by a "push" from the ground would have to be so high that its friction with the air might produce heat sufficient to melt it.  This teat, due to "adiabatic compression," would produce a temperature of about 750 degrees centigrade - too much for the unfortunate "crew" within and too much for any metal of which the projectle might be made.  The final objection to a projectile, perhaps, is that future space-flyers could not expect to have the lucky accident which resulted in Jules Verne's travellers returning, and they would want some form of propulsion aboard in order to get them back from the moon!

Question: Do we know how fast we should have to travel to leave the earth's field of gravity?

Answer: It can be calculated exactly, without much difficulty.  The speed is roughly seven miles a second.  With any speed less than this, the space-ship would not escape the earth's gravity.  This very high speed, seven times the maximum speed reached by a German V2 rocket, cannot be reached with any known fuel, not, at least, by using it as we do today.

Question: But you answered my very first question by saying that a rocket flight to the moon was possible now.

Answer: Not quite.  But let me finish my explanation.  The difficulty is, of course, that a rocket has to carry its own fuel with it, so that we have a huge weight of rocket with a very small  amount of "pay-load."  The earlier experimenters realised that with the solid fuels they used in rockets any long-distance flight was out of the question.  It requires 21,000,000 foot-pounds of energy to life one pound of material beyond the earth's field of gravity.  Even liquid hydrogen and liquid oxygen, one of our most efficient fuels, might give only 5,500,000 foot-pounds of energy per pound of fuel.  Now, we have to remember that most of the fuel must be carried at the start - in other words, that the fuel must lift itself as well as the "pay-load": that is, the hull, instruments, passengers, and so on.  We can estimate that 250 lbs. of a hydrogen-oxygen mixture would be required to lift one pound of space-ship.  Thinking in terms of the smallest rocket, this ratio between fuel weight and load makes a practical rocket with this fuel almost out of the question at the moment.  We have not yet had much experience with fuels of this kind.

Question: The problem of astronautics at the moment, then, is finding the right fuel for rockets?

Answer: That is the essential problem that has to be solved first.  All the rest, one might dismiss as "engineering details."  This does not mean that there are not many difficulties, but simply that there seem to be no fundamental ones.  There are fuels which could solve the problem on the horizon, so to speak.  Atomic hydrogen, if we could prepare it in quantities, would provide sufficient energy for a practical space-ship.  And, of course, atomic disintegration would give us energy and to spare.  Compared with the 3,860 calories per kilogram provided by liquid hydrogen and oxygen, the disintegration of matter would provide 21.5 billion calories a kilogram!  Unfortunately, although we know now how to realise the energy of the atom with explosive force, we do not yet know how to released it at a controlled rate, as would be essential for its use in a rocket, or, for that matter, for any other form of transport.  The leading nations are spending millions of pounds on the research necessary for the solution of this problem.  Experts have suggested that it will be solved in ten or twenty years.  I believe that it is on a space-rocket that controlled atomic force will be used.

It does not seem likely that this atomic energy will be cheap enough to compete with coal and oil, at any rate for decades, and it will be used for purposes only where oil and coal are unsuitable.  The powering of a space-rocket of course calls for atomic fuel.

Question: Does that mean we have to wait for the harnessing of atomic energy before we start practical experiments on space-rockets?

Answer: By no means.  There is another solution to the problem.  I have said that the most efficient fuels we can use today are not good enough to get a rocket out of the earth's field of gravity because of the weight-energy ratio.  But by some improvement in them, we could produce a "step rocket" that would reach the moon.  If we could double the power of a German V2 and turn it into a step rocket, it would in theory easily be able to escape the earth's gravity.  Instead of the ton of explosive in its warhead, it would carry another rocket.  At the moment when the main rocket had expended its energy, and the V2 would have reached the top of its trajectory, the main rocket would be dropped off and the second rocket would come into action, carrying the hull further.  To reach the moon, we should need a "three-step" rocket, and exact calculations have been made of its size on the basis of a fuel just twice as good as that of the V2.  To carry 100 lbs. of "pay-load," the rocket would have to weigh about 30 tons at the start.  The first "step" would weigh about 28 tons, the second step about 2 tons, and the third step a mere 1,000 lbs.  Of course, this amount of "pay-load" wouldn't permit any human being to be aboard, but it would make possible the carrying of automatic radio equipment, or even flash-powder that would show a "hit" had been secured, and would be invaluable for checking data.

Calculations show that to construct a similar rocket to carry human beings, assuming the total weight of passengers' compartment, food, oxygen, equipment and passengers to be only five tons, would require a rocket that in its first stage would weigh no less than 40,000 tons!  It is true that we build battleships of this size, but if we must be practical we must admit that the possibility of any nation spending the huge sum required on a purely experimental rocket of this kind in the near future is extremely small.

Question: Then the first rocket on the moon is likely to be quite a small one, and not a bit like the curious space-ships which have been described by many writers of science-fiction?

Answer: I think that before we begin firing rockets at the moon, we shall carry out a great number of other experiments.  We shall send rockets to heights of 100 and 200 miles.  This will not only be simpler, but extremely useful.  Fitted with automatic recording and wireless transmitting instruments, the rockets will give us data of great value to meteorology.  Before a decade has passed, sending up these rockets may be a daily routine, like the present "weather patrol" in an aeroplane.

The next step might be to send up a space-rocket with a velocity calculated to turn it into and artificial "satellite" of the earth.  I have given the velocity required to escape the earth's field of  gravity.  But if a somewhat less velocity were used, the rocket would reach a point where, instead of going on towards the moon or being attracted back to the earth, it would be held in space, making an orbit round the earth like the moon.  There are a number of possible orbits, and the exact velocity required for each in simply calculated.  Rockets fired in this way would serve a number of useful purposes, apart from checking calculations.  For instance, it has been suggested that they could be fitted with automatic wireless transmitters relaying transmissions from the earth.  The advantage would be that we could get world-wide television and first-class twenty-four-hour wireless service in a way quite impossible with earth-bound equipment.  This proposal has been put forward quite seriously as a solution to the difficulties arising from the very short range of television transmitters.  All the necessary mathematical calculations have been made for this artificial satellite.  For power it might use the sunlight, but it would obviously have to be visited periodically for "servicing," and so the first serious space-traveller may not be visitors to the moon, but engineers going 60,000 miles to erect radio transmitters on artificial satellites built up from material carried from the earth by a series of rockets.

Question: Apart from fuel, what are the chief practical problems to be considered in designing a space-ship?

Answer: I should put first the difficulty of gradual acceleration.  The rocket must not "take off" at anything like full speed for two reasons.  If there are human beings aboard they could not stand the acceleration.  They would be crushed as if by a weight of thousands of tons, and it would be difficult also to design a structure able to withstand the strain.  Even if there are not human beings aboard, we have to consider the friction with the air.  The rocket must not attain full speed until it is clear of the earth's atmosphere, or it might become incandescent like a meteor and break up.  And this does not mean simply going slow until it has reached the stratosphere.  The actual density of the air hardly enters into this question of adiabatic compression.  Probably not until the space-ship has reached a height of 80 to 100 miles will it radiate heat at the same rate as absorbing it, and it would have to be designed not to reach its maximum speed until it was at least 600 miles from the earth.  Once free of the air, with no friction to brake it, the rocket could be worked up to a speed of 20,000 miles an hour.

Question: Could human beings stand this tremendous speed?

Answer: Human beings can stand any speed, or, more correctly, perhaps I should say any speed up to that of light.  We do not yet know the answer after that.

It is not the speed that causes the trouble, but the acceleration.  After all, you and I at this moment are travelling far faster than any record-breaking airman, and we are not even conscious of movement.  The earth is not only revolving on its axis at about 1,000 m.p.h., where we are, but also travelling round the sun at a colossal speed as well as moving through space at miles a second.  No, it is not the ultimate speed, but the rate at which it is reached that we have to worry about.  Everyone is familiar with being pressed back against his seat when a car suddenly accelerates.  With a rocket, this effect would be far greater.  There would be a noticeable weight pushing on the pilot, and he would feel as if a load several times his own weight had been thrust upon him.  This sensation would remain so long as acceleration went on.  And it is plain that if we are to reach the moon, 240,000 miles away, in any reasonable time acceleration must be fairly rapid.  Experiments will show what are the limits of human endurance in this respect.  Some tests have already been made.  By any reasonable calculation, the space-voyagers would have to expect eight to ten minutes of acceleration during which they would feel as if about three times their own weight was bearing down on them.  This would be endurable, although on one would pretend it is likely to be comfortable.  I anticipate that there will be specially designed hammocks in which the travellers will lie during the period of acceleration.  The effect is lessened when in a prone position.  The war has given us considerable experience of the effects of acceleration and methods of relieving them.  Even the pilot will have to lie in a specially sprung rest at the start of the voyage.

Of course, when the rocket begins to slow down again, either of a landing on the moon or a return to the earth, there will have to be the same precautions taken to decelerate slowly.

Question: Speaking of landing on the moon, how will it be carried out?

Answer: When the space-ship reaches the point -much nearer the moon than the earth, because the moon is smaller - where the gravity of the earth equals that of the moon, it will presumably shut off its rocket motors entirely and begin to fall towards the moon by gravity.  Unchecked, it would accelerate until it was reaching a speed of some 10,000 feet a second.  Obviously this will have to be checked.  Apart from the fact that the moon does not appear to have any atmosphere, it is doubtful whether any parachute could be made strong enough to act as a break.  We must suppose therefore that the space-ship will have rocket motors in its nose or be able to reverse itself so that the force of its rocket motors is applied against the pull of the moon.  It would thus be possible to reduce its speed to a mere one mile an hour so that it landed with hardly a bump.

This is merely a reversal of the process at the take-off.  The German V2 rose very slowly for the first few feet - it went up the first ten of twelve feet as if it were being slowly lifted by a crane.  The landing would have to be made by this process in reverse, but with much slower deceleration than would be necessary in a pilotless rocket.  In practice, I should expect to see the first few flights made to circle the moon rather than land on it.  Landing would call for special "space suits" and an air-lock in the passenger compartment of the space-ship.  Incidentally, it is a very interesting point that when the rocket was in flight in space the passengers could, if they liked, quite safely get out of the air-lock and travel in space beside the space-ship - of course wearing their special suit to provide oxygen and protect them from the intense cold.  They would be advised to have a rope to enable them to climb back aboard the space-ship, but they would be able to walk about or more probably float about, without any risk of being left behind!

Question: How would that be possible?

Answer: Because during the voyage they would slowly lose weight.  I do not mean that fat would drop off them, but simply that they would feel as if they weighed less.  The effect of the earth's pull would be rapidly diminished and would eventually become nothing.  And even when they approached the moon, the lesser gravity of the satellite would make them weigh very much less.  This would undoubtedly give rise to complications and even dangers inside the space-ship.  Have you ever thought what the world would be like if things had no weight?  You would find the greatest difficulty - literally - in keeping your feet on the ground.  You would take a step and find yourself going up instead of forward.  That is what would happen inside the space-ship, and, obviously, the designers would have to provide not only "handholds" on the walls and ceiling of the compartment, but also "toe-holds" in the floor.  Somebody once suggested to me that the passengers should have lead in their boots, but of course that wouldn't help because the lead would also weigh nothing.  Steel boots with a magnetic floor might be more helpful in keeping their feet on the floor.

Then, since nothing would weigh anything, everything would have to be more securely screwed down than in a ship in a storm.  Otherwise books and papers would float off the table into the air and you might find your plate of food on the ceiling.  As a matter of fact, on of the great problems that has troubled designers of space-ships is how to feed their pilot and passengers.  Water would not stay in a cup or glass, and it is probable that it would either have to be sucked from a closed bottle or, more probably, from a damped cloth.  The space-ship passengers would certainly be unable to wash except by applying cream.  They would have to take extreme care over every movement, or in a few minutes there would be a terrible crop of bruises and broken limbs.  Doing everything with allowance for the sensation of weight and effect of gravity is such a deeply ingrained habit that it would be difficult to change it.  This feeling of weightlessness may seem a small matter, but it has given those specialising in the physiology of space flight great concern.  They feel that, apart from the danger due to unaccustomed movement, there would be great physical and mental discomfort.  The passengers would feel like a man dropping in a lift, not for a few seconds, but for hours.  They have, therefore, tried to devise artificial means of restoring "gravity."  Two ingenious suggestions have been made.  One is to accelerate slowly and continuously so as exactly to simulate the earth's pull: 32 feet per second.  The other is to design the passenger chamber in the shape of a cylinder so that it could be continuously rotated in order that passengers would be "pulled" as if by the earth.

These ideas are ingenious, but not very practical.  In the first instance, the acceleration would build up to the point where it would be necessary to have a speed of 500 miles a second after 24 hours.  In the second case, the passenger chamber would have to be enormous if passengers were not to be whirled round so often that they would be completely giddy - a minimum diameter of 100 feet for the chamber is suggested.  To both there is the objection that they are enormously expensive in fuel, the acceleration idea particularly, because for a rocket slow acceleration is wasteful.  We have to slow acceleration for practical reasons, but to slow it further in this way would mean a huge additional load.  In the second instance, much fuel would be consumed in rotating the chamber.  The objection of waste of fuel does not hold good if we assume the use of atomic energy, when there would be fuel and to spare.

To be at some spot where gravity is less then that to which we are accustomed would be worth almost any discomforts as an experience.  The trip itself would be a marvel, for we should see our own earth shining in the distance, with other planets brilliant against the blackness of space.  Occasional meteorites might gleam in the distance, and when we arrived our bodies would feel quite buoyant.  A jump might take us 20 feet into the air, and it would be easy to hit a golf ball for about a quarter of a mile.  If we tried to box, a good left to the shoulder would send us sailing up out of the ring, so greatly would what we call our weight be reduced.  Medical men have examined the possible dangers of weightlessness to the human functions.  In fact, most of these functions proceed by muscular activity rather than gravity - our food is pressed into the stomach, as well as dropping into it, and is digested quite independently of the pull of gravity.  There might be some displacement of organs, but this could be overcome by special clothing.  One writer has suggested that weightlessness would speed up the beat of the heart until it was fatal.  We find the same objection being made 150 years ago to speeds of 60 m.p.h. on a train!

On the whole, I think all these difficulties will be overcome without more fatalities than we had in learning to fly.  The first rocket flights with human passengers will be comparatively short, and we shall be able to test theoretical dangers practically.  But it is probable that space flight, like very high speed flight on earth, will in the first instance be only for fit young men with strong bodies, willing to suffer discomforts.  I have no doubt that there will be plenty of volunteers for crews of space-ships.  There has never been a lack of pioneers ready for dangerous exploits of scientific value.

Question: Wouldn't the millions of meteors in space be a grave danger to any space-ship?

Answer: You have in mind, of course, the possibility of a space-ship coming into collision with one of the - not millions but thousands of millions - of meteors constantly flying through space at high speeds.

It is true that if a space-ship did collide with a meteor the results might well be fatal.  The space-ship would have to be enormously strong, but the thickest steel would be of little avail against impact with even the smallest body travelling at a speed of up to forty miles a second.  The impact might result in the meteor "exploding," the momentary heat melting the hull of the space-ship at the point of impact; or perhaps the meteor would pass right through it, like a bullet going through a piece of wood.  In either case, the hull would be punctured, and even if there were no other effects, such as destruction of vital controlling devices or ignition of fuel before time, the oxygen in the hull would be sucked out into the vacuum of space, and life inside would become impossible.  It all sounds  - and would be - extremely unpleasant.

This question of collision with meteors has worried many who have concerned themselves with journeys in space.  Various ingenious ideas have been put forward for protective devices, including "protective rays," although the science-fiction writers who have used them have on told us the nature of the "rays" which are to cause the meteors to break up as they approach the space-ship.  It has been suggested that the navigator of the space-ship would be able to steer clear of at least the larger meteors; but it seems doubtful whether these would be visible.  We only see a meteor when it becomes incandescent in the earth's atmosphere.  There is the further objection that pilots of modern aircraft have all they can do to steer clear of other aircraft at seven miles a minute, and that manoeuvring a space-ship moving at hundreds of miles a minute to avoid a meteor moving at many miles a second would be beyond the capacity of human senses.  Some sort of radar device might be invented to make for automatic steering clear of meteors, but this calls for a delicacy of control which we certainly haven't got at the moment.

Question: Then you think that space-travellers would have to take a chance on being struck by a meteor?

Answer: Yes.  But it is not such a great chance as might seem, not more than the chance of being struck by lightning on the earth.  After all, there are lightning flashes somewhere on the earth every second of every day, but the chances against any individual being struck are millions to one.  So in space, although there are millions of meteors, they are really quite scattered.  One scientist has calculated that the average distance apart of meteors is 250 miles.  For a space-ship to be struck by one, therefore, would be an unlucky chance rather than a probability.  Dr. Goddard, the noted American pioneer of rocketry, calculated that the odds against a space-ship colliding with a meteor on a journey to the moon are 100,000,000 to .  It looks therefore as if the space-flyers will take a chance on collision, just as Columbus took a chance on colliding with a wreck.  Collision with a meteor would probably be fatal, although it is possible to imagine the use of "collision mats" for quickly closing a hole.  But it would be only one, and by no means the greatest, of the hazards of space flight.

Question: I have heard a lot recently about some very penetrating rays called cosmic rays, which fall on the earth in small amounts, but come from outer space.  Mightn't they destroy a space-ship?

Answer: It is quite true that cosmic rays originating in space (we don't quite know how) have great energy and power of penetration.  Whereas an inch or two of lead is sufficient to stop X-rays, a wall of lead eight feet thick is required to shut out cosmic rays.  They appear to use their energy destructively, breaking up matter on the earth.  We can only discover this by the most delicate measurements, because cosmic rays are comparatively few and atoms are countless.  We believing that the majority of cosmic rays are absorbed by the ozone in the earth's atmosphere before reaching the ground.  The rays are certainly more numerous at great heights than at sea-level.  But we don't know yet whether in outer space they are so numerous that they would seriously affect human beings.  Certainly, balloonists and high-flying airmen have not noticed any effects.  The effects we should expect would be similar to those experienced after exposure to radium.  Cosmic rays are a problem, but one that space-flyers will meet when they come to it.  Long before the first passenger-carrying space-ship leaves the earth, exploratory rockets carrying instruments will have brought back from space precise information about cosmic rays there, and designers of space-ships will know just what - if anything - they have to contend with.

Question: You don't think that cosmic ray will prevent flying in space?

Answer: On the contrary.  I am sure that even if they prove to be a serious obstacle, it will be overcome.  They may even prove to be to benefit: in this way.  If the enormous energy of cosmic rays could be harnessed, we might solve the problem of fuelling our space-ships in the simplest possible way.  Supposed we could use the energy of cosmic rays to release atomic energy, then we have our fuelling problem solved as simply as that of a sailing ship which picks up its "power" as it goes along.

Question: How will space-ships be navigated?

Answer: There will have to be either auxiliary rockets in the sides of the hull, turning it to right or left and up and down, or possibly rudders in the stream of gases coming from the main motors, as in the case of the German V2.  In steering the space-ship, the navigator will have to depend upon the fixed stars.  But I do not think navigation will prove a very difficult task.  For one thing, the space-ship will largely act as a projectile, and it will be possible to calculate its path very accurately.  It will be "aimed" at the start in accordance with calculations made by astronomers, and the movements of bodies in space can be told to the minute.  The sun and moon are rarely a fraction of a second late or early in appearing at the times calculated by astronomers years before.  Against this advantage, we have the point that everything must be calculated in advance.  There can be no hanging round waiting to land on the moon, as a sea-ship waits outside a harbour!  The pilot will have to keep the exact speeds laid down, otherwise, instead of meeting the moon at the calculated point, he will find himself thousands of miles away and quite unable to "catch up," at any rate on his limited fuel.

The problem becomes more complicated when we consider journeys to Mars and Venus, the only two planets to which we can consider space flights within a measurable time.  Here, instead of a journey of a mere 240,000 miles, we are dealing with journeys under the best conditions of 26 to 50 million miles.  Given very high speeds, the journeys will still take many days.  The navigator, in contrast to the airman and the sea-pilot, will be concerned in plotting a course to a place which will be in a very different position at the end of his journey from what it was at the start.  Moreover, on these long journeys, the pull of the sun enters into the calculations.  The space-ship will have to be steered with allowance for the pull or the sun.  For a journey to Venus, the rocket must, of course, attain the speed of 7 miles a second necessary to leave the earth's field of gravitation.  It will also have an "acquired velocity" of 18 miles a second from the earth - just as a bomb dropped from an aircraft travels at the same speed as the aircraft.  By the time the space-ship reaches Venus, it must have speeded up this velocity to that of the planet nearer the sun - 22 miles a second.  If it were going to Mars, it would have to cut down this velocity to 15 miles a second.  Fortunately, as I have said, all these movements can be calculated without any error; but the travellers will have to be men of science, with complete faith in their calculations.  I can imagine that on the month-long journey to Venus or Mars it might at times seem to them that they were going in quite the wrong direction, out into uninhabited space.

Question: Will it be possible for the space-ship to keep in touch with the earth during its flight?

Answer: You are looking forward to a running commentary being broadcast by the B.B.C.!  There are great technical difficulties in the way of radio communication.  I think the method of communication, if any, is more likely to be by heliograph or light-signals.  This has been highly developed during the war, and is no longer a question of flashing dots and dashes by Morse code.  Sound can be turned into light-signals through a microphone.  On being received on the earth, the light-signals would be turned back into sound or, if desired, into radio signals.  I am sure communication with the earth will be considered almost a prerequisite of space flights.  The reason may sound a little grim.  It is not that the flyers will need advice from the earth; but they will be men engaged on a scientific expedition and not a joy trip.  They will realise, on the early flights, that the chances of returning are probably small.  They will not want their invaluable experience and data lost.  You remember, during the war, that men removing the fuses from new types of delayed-action bombs and booby-traps had microphones so that they could dictate a running commentary; if they war blown up, the next man would avoid making the same mistake.  It will be the same with the pioneer space-flyers.  They will not mind risking their lives so much if they know that, it the worst comes to the worst, they will have helped those who come afterwards.

Question: Do you think then that lives will be lost?

Answer: Let us be honest.  Learning to fly at 90 m.p.h. just above the earth was simple compared to learning to fly at seven miles a second for millions of miles!  We must expect lives to be lost, that does not mean to say they need be thrown away.  I am confident that some of the finest brains in the world will vie with each other for the honour of making the first flights.  I always remember how, when in the early days of ballooning it was supposed that ascending to a few thousand feet would mean sudden death, it was arranged to send up a pig or condemned criminal on the pioneer flight.  An eminent French savant was indignant.  Send an animal or a man who had forfeited his right to live on such an important expedition!  He would go himself, and be honoured, if necessary, to die!  That is the spirit which has animated many great scientists.

Question: But will it really be worth while?  You have given a lot of interesting information about journeys to space, but you have not give any good reason why we should make these journeys, especially it they mean risking the lives of clever men.

Answer: There are many reasons.  First, I should say, you won't stop men trying to reach the moon.  The love of adventure is too deeply ingrained in human beings.  It is one of the reasons why they have come out "top" in the animal kingdom, survived when other species have stayed still or decayed.  Sometimes the spirit of adventure and competition may seem dead, but it is there, waiting for an opportunity to show itself, and a journey to another world offers the most extraordinary opportunity since man became civilised, although perhaps no more startling than, say, the voyage of Christopher Columbus.

There are other reasons.  By space flight, and even by research and experiment directed towards it, we shall gain a great deal of knowledge that will be valuable in many different ways.  We shall improve our weather forecasts and wireless communications almost certainly.  We may tap new sources of power.  We might, for instance, find on the moon or Mars vast quantities of radio-active matter which would fuel our rocket engines at negligible cost.

Then there is the great curiosity of human beings, the real scientific curiosity, the desire to know.  Coupled with the love of adventure, this has been the driving force of the human race for thousands of years.  But for it, men would have remained a few hundred in number, living in caves.  Cetainly without it there would have been no science, for science is simply organised curiosity, the continual asking of "Why?" and "What happens?"  We can speculate about the moon, Mars and Venus, but in the end we want to know.  And the best way of knowing is to go there.

I do not rate so highly the reasons sometimes advanced: the desire to escape from a troubled world and build a "Utopia" from the beginning again.  We are more likely to build Utopia on this world, where we are "conditioned" to the right amounts of air, light and heat, than on the airless moon, on arid Mars, or on humid Venus.  We may, however, find there forms of life of extraordinary interest, adapted to these conditions and quite unlike anything we know on this earth.  The possibilities are fascinating, and fact may in the end be far more extraordinary even than the fantasy of science-fiction.