Tag Archives: space travel

583. Mutually Assured Destruction

I taught middle school science for twenty-seven years, and every year I taught the manned space program. It was never called for in the required curriculum, but I always managed to shoehorn it in while still teaching everything I was required to. It wasn’t just because I loved the subject, although I did. There were plenty of things in science that I loved but never mentioned.

The plain fact is that seventh graders don’t listen unless you excite them, and the manned space program was exciting.

Here is a schtick I used in my middle-school classroom all through the eighties and nineties. The subject was, “What motivated Americans who didn’t care about space to spend billions to outrun the Russians in the Space Race?”

I would choose two pushy, self-assured young guys and call them to the front of the room. I would put them face to face, about ten feet apart, and say, “Now, imagine each of you has a .45 automatic, and each of you hates the other one. We’ll call one of you America and the other Russia. I don’t want to insult you, so I won’t say which is which.

“Point your guns at each other. (They would gleefully assume the position.) If either one of you fires, the other will have just time enough to pull the trigger, too. You will both go down. If you sneeze, though, you’re a goner. If you blink, you’re a goner. If you look away, same thing.

“Now hold that pose for fifty years.”

Clearly, I couldn’t get away with that today, but this was pre-Columbine. My kids were thinking about cops and robbers, not  a terrorist who was out to kill them.

Do I have to point out that the guns represented the American and Soviet nuclear armed arsenal of missiles? It was a demonstration of Mutually Assured Destruction, also known by its entirely appropriate acronym MAD. If either side had attained an overwhelming superiority in number of missiles, the delicate balance would have been disrupted. Witness the Soviet’s parading their missiles in Moscow, and taking them several times around the block to look like they had more than they did.

The balance could be disrupted by having missiles closer to the enemy than the enemy did to us. Witness secret American missile bases in Turkey, on the Soviet border, which led them to put missiles in Cuba. The Cuban Missile Crisis was not an unprovoked Soviet threat.

The balance would have also been disrupted by an effective missile defense system. There is no such thing as defensive in the MAD scenario.

What does this have to do with space travel? Two things, one positive and one negative. The entire business was a race for the nuclear high ground. If either side had managed to put an orbital missile platform into orbit, it would have been bad news for the other side. That was not possible, so each side tried to maximize their capabilities in space while proving to the hundred plus other nations on the Earth that they were the firstest with the mostest.

I would repeat that in Russian if I could write Cyrillic.

All this turned into the Space Race, culminating in a manned lunar landing, It’s nice that something good came out of all that nonsense.

The other side of the coin was a reinforcement of fear of nukes, whether it was bombs, powerplants, or space drives. In the fiction of the sixties, the solar system was filled with nuclear powered spacecraft. In the real world, fear killed the idea.

Should we have nuclear spacecraft? I think so, but it isn’t for me to say. It isn’t for you to say, either. It isn’t even for the people to say.

Why? Because we’ve shifted our focus from the Russians to the Chinese.

If history is a guide, we will have a nuclear spacecraft — a few years after the Chinese launch their first one. We’ll be running behind and playing catch-up as usual.

Remember Sputnik?

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582. Newtonian Nukes

Everybody who read the last generation of science fiction juveniles before Apollo knew Newton’s third law:

For every action, there is an equal and opposite reaction.

The demonstrations in popular science books of that same era usually went something like this: imagine a person on a frozen pond wearing ice skates, throwing bricks. Every brick he throws will move him backward. If we could ignore the friction of skates on ice, it would be proportional. That is, if a hundred pound man  . . .

Okay, side issue. Most Americans back then, and even today, don’t think in kilograms or kilometers, nor distinguish mass from weight in everyday thought, so . . .

If a hundred pound man throws a one pound brick at ten miles per hour, it will propel him backward at one tenth of a mile per hour. 1 times 10 = 0.1 times 100. We are ignoring friction from the ice, the atmosphere, and probably a bunch of other things.

So, if you want to go faster, throw more bricks, right? If you throw a thousand bricks, you should be able to go pretty fast, right? Wrong, because the first brick your throw in the new scenario will have to move not only the hundred pound man, but also the other 999 pounds of bricks.

Increasing the amount of fuel carried quickly brings about diminishing returns. More fuel alone is not the answer.

In a Newtonian scenario, the faster the propellant leaves the rocket engine, and the more propellant you use, the faster you can go. LOX and LH are probably near the practical  maximum for propellant speed by chemical reaction. The logical next step would be to use a non-chemical energy source to activate our propellants, such as a nuclear powered rocket. Even that won’t get us to the stars, but it makes sense for travel inside the solar system.

Before Apollo, everyone who read science fiction knew that, which is why the Scorpius and her sisters in the Rip Foster book are nuclear powered. So were the ships in Bullard of the Space Patrol, a marvelous fix-up novel by Malcolm Jameson that no one remembers today. So were the ships in the Dig Allen series (1959 – 1962), six great but forgotten novels, and the ships of the Tom Corbett books, which were not so great and are not completely forgotten.

Star Trek put all these early concepts out of business. Warp speed was a necessity for roaming the galaxy, but it made nuclear rockets look old fashioned. I think that’s too bad. There is still room for them in science fiction, and certainly in real life.

I haven’t mentioned Heinlein yet. The Rolling Stone was nuclear, but he quickly moved on to torch ships, which had the capacity of total annihilation of matter. He never explained how that could be done, but the result would be “propellant” moving at essentially lightspeed. You can’t get faster than that without warp drive. His torch ships roamed the solar system and went on to explore nearby stars.

I stole that schtick for my coreships in Cyan, with a twist. See 23. Star Drives.

In a rational world — which we will probably never inhabit, but we can still write stories about — you would might use chemical rockets to get to LEO (low Earth orbit), nuclear powered rockets to zip around the solar system (fission powered if you were writing in the sixties, fusion powered if you were writing today), and “torch ships” to reach nearby stars. Beyond that, you would need FTL (faster than light) vehicles which, by our present understanding of the universe, are impossible.

Too bad about FTL, but why are we still using chemical propellants in the real world fifty years after Apollo? Fear of nukes, of course. There will be more to say about that on Wednesday.

578. That Odd Spiral

This is the track of Sputnik, the first satellite launched from Baikonur Cosmodrome at latitude 46 degrees north. Launches from Cape Canaveral followed paths that were more flattened out because they were launched from 28 degrees north.

The orbital path shown above was to be found in thousands of publications at the dawn of the space age. Everyone carried the image in their heads, but today I had a hard time finding it on the web. My how times change.

Every space geek in 1960 would have known everything in this post, but then Star Trek came along. Kirk and Spock, and especially Uhura, went at warp speed and walked around on the floor like it was a sound stage in Hollywood. No weightlessness there. Then Star Wars came along and all veracity went out the viewplate.

There were a lot of very basic principles of physics that governed the space program, which Hollywood had to ignore.

Let’s begin on the ground. The Earth rotates eastward at a certain number of miles per hour. (We are channeling 1960 here. None of the published reports on space used the metric system back then.) Any geek with a pencil could figure out rotational speed by dividing equatorial circumference (25,000 miles to any 1960’s space fan, forget the decimals.) by the length of the day. !042 miles per hour eastward at the equator.

A spacecraft in low Earth orbit flies at 17,500 miles per hour. Actually that varies, but that was the figure in all the space enthusiasts books at the time. If you launched a rocket eastward, you started with about 1000 mph of free speed. If you launched westward, it would cost you 2000 mph of extra speed. You wouldn’t gain the natural advantage, and the rocket would be going 1000 mph the wrong way as it sat on the ground.

Everyone launched eastward.

There was actually another reasonable option, launch north or south. We’ll look at that choice at the bottom of the post.

Actually you don’t get all of that speed advantage. The circumference of the Earth is less as you move northward, lowering the eastward speed. If a United World wanted to choose the most advantageous place for a spaceport, it would be at high altitude somewhere on the equator. That happened frequently in science fiction.

Neither America nor Russia had a far southern point suitable for a space port. America’s best choices were Texas and Florida — the same two states Jules Verne pointed out in From the Earth to the Moon. Florida had the added advantage of having the Atlantic ocean to eastward, which provided a place to drop first stages and failed rockets, without landing on anybody’s house.

Russia built in the desert at the same latitude as Portland, Oregon, but they always chose secrecy over other factors.

Launching eastward is an exaggeration, of course. Straight east from either site won’t work; launches had to be aimed south of east to bring the center of the orbit into line with the center of the Earth’s gravity.

You might think that a launch from Canaveral would return to Canaveral after one orbit, but that isn’t true. The Earth is rotating eastward, so a spacecraft launched from Canaveral will pass over a spot about a thousand miles west of Canaveral on its first return. And so forth. Which is why the cosmonauts were a thousand miles off target after one extra orbit in yesterday’s post.

All this gives us that odd spiral at the top of the post.

In fact, you could launch a spacecraft into orbit from any point on Earth as long as its orbital path circled around the Earth’s center of gravity. Further south is simply more efficient.

You could even launch satellites due north, and we do, from Vandenberg Air Force Base on the west coast of California. Such satellites also spiral around the Earth, but they cover every part of the Earth eventually. Weather and spy satellites use this orbit.

Southeastward launches from Canaveral and Baikonur don’t cross over the far north or the far south.

What about a satellite exactly circling the equator? In low Earth orbit, it would circle the Earth about every 90 minutes. The moon, a quarter of a million miles further out, circles the Earth in 29 1/2 days. Clearly, even for math challenged enthusiasts, the further out the satellite, the slower it travels in orbit. At some distance from the center of the Earth, it would take a satellite one day to circle the Earth. Seen from Earth, it would appear to hang in one spot above the equator.

Everybody should know that, because that is how communication satellites work. The first person to recognize the fact and calculate the distance was Arthur C. Clarke, known even to non-SF readers from 2001, a Space Odyssey. The connection between science and science fiction has always been close.

577. The First Space Walk (2)

The space suit worn by Alexei Leonov on the first human space walk. On display at the Smithsonian National Air and Space Museum. Author: Nijuuf

This is the rest of Tuesday’s post. If you haven’t read it yet, take the time to do so, or this won’t make much sense.

Alexey Leonov had extreme difficulty reentering the airlock. His space suit had over inflated; the boots and gloves had slipped beyond his toes and fingertips, and his suit had increased in girth. He had to vent part of his rapidly depleting oxygen in order to bring his suit down in size, and even then he entered the airlock head first, instead of feet first as planned. Once inside the airlock, he had extreme difficulty contorting his body to close the outer door. All this time, his body was heating up dangerously; surrounded by vacuum, there was nothing to carry away the heat his body was generating.

Once air pressure had been restored in the airlock, Belyayev opened the inner door and Leonov was safe. For the moment. As he said in an article for Smithsonian’s Air and Space magazine in 2005, “the difficulties I experienced reentering the spacecraft were just the start of a series of dire emergencies that almost cost us our lives.”

The mission had achieved it’s goal and it was time to return, but just before the scheduled time for firing retro rockets the cosmonauts discovered that their automatic guidance system was malfunctioning. It took time to prepare for manual entry, so they had to wait one orbit, which would make them miss their return point by a thousand miles. (To find out why it would be a thousand miles, see the post coming on March 25.) Most of that orbit they were out of radio communications. (The Americans had built a string of radio relay stations around the world to maintain constant communication with their astronauts, but the Soviets had not.)

When communications were restored, ground control asked them where they had landed.

Their orbital path was set; the moment of firing their retro rockets would determine where on that orbit they would land. They chose a target just past the Urals. Using the clumsy and difficult manual backup equipment, they achieved the correct attitude and fired the retro rockets in the conical rear portion of the craft called the orbital module. The orbital and landing modules were supposed to separate ten seconds after retrofire. They didn’t.

The two cosmonauts knew immediately that something was terribly wrong. Instead of the steady press of force against their backs as they decelerated, they found themselves whipped about by confused forces that exceeded ten gravities. A communication cable between the two modules had failed to release, and now both modules were whipping about each other, tethered by the cable.

Finally, about 60 miles up, the cable burned through and the cosmonauts were freed. The drogue chute deployed, and then the main. All was peaceful and in order – briefly. Then it became dark as they dropped below cloud cover, the final rocket fired to slow them to landing speed, and they touched down in six feet of snow.

They were 1200 miles beyond their intended landing point.

They blew the explosive bolts to release the hatch. It didn’t open. They had landed in the middle of a forest and the hatch was held shut by a tree. By yanking violently they dislodged it and it fell away, lost in the snow.

They made their way out of the spacecraft and waded through snow to a small clearing. Those back at headquarters had not heard their landing signal, but a passing cargo plane had. It circled, and was soon joined by other planes and helicopters, but none of them could land in the rough taiga. Pilots threw a bottle of cognac; it broke. They threw warm clothing which got caught in the trees, but at least two pairs of wolfskin boots made it to the ground.

The light was failing. The cosmonauts returned to their craft for shelter. Leonov was walking in calf deep sweat still trapped in his space suit from his space walk. Both cosmonauts stripped, removed the liners from their space suits and wrung them dry, then put the on again along with the wolf skin boots. They abandoned the useless space suits and crawled into the landing module for the night, well aware that the taiga was filled with bears and wolves, and that this was mating season, when they were most aggressive.

The hatch was out of reach. The lights failed, but the circulation fan ran all night, adding to their misery. The temperature dropped to 22 below zero.

A rescue party arrived on skis the next morning; they chopped trees to build a small log cabin and a big fire. The cosmonauts spent a second night, then skied out to where a second, larger party had chopped down enough trees for a helicopter to land.

I guess they made ‘em tough in those days. I suspect they still do.

576. The First Space Walk (1)

I posted this in 2016, under the title Spacecraft Threatened by Bears. The title was snarky but accurate. Back then I had few followers, so it seems time to post the amazing story again.

My admiration for the people of the early American space program is boundless, but the Russians were no slouches either. They were the first to perform many feats, including the first space walk, during the flight of Voskhod 2 on March 18-19, fifty-four years ago.

I had the great good fortune of living through the early days of manned space flight. I was nine years old when the Russians orbited the first satellite, and the early manned flights came when I was in high school. I watched every American launch with fascination and envy, but the Russian launches were shrouded in secrecy. I knew only the bare minimum that all Americans knew. I’m not sure the president knew much more.

During those early days, nothing was routine. Every mission was dangerous. They still are, of course, but not so much as then. American failures were there for all the world to see, while the Soviets kept their’s secret.

After the breakup of the Soviet Union, information about the early Russian space program became generally available, but by then few people cared. I did, and I sought out the stories.

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Oceans are big targets and landing in water cushions the fall. That is why Americans always splashed down. The Soviets were unwilling to land their craft anywhere outside of the USSR for reasons of security. Their hard landings had an effect of the design of their spacecraft.

The first six manned Soviet spaceflights were aboard Vostok craft, which came down on land — hard. Vostok astronauts wore space suits throughout their flights and landed by personal parachute separate from the capsule. Before the second generation Soyuz spacecraft came on line, the Soviets launched two additional manned missions on modified Vostoks called Voskhod.

On Voskhod, an additional rocket was added to the spherical descent module to fire at the last minute. This softened the landing enough so the cosmonauts could remain within the descent module all the way to the ground. Since ejection seats were no longer used, the weight saving allowed Voskhod 1 to carry three astronauts.

Voskhod 1 cosmonauts flew without space suits, as did early Soyuz missions. Voskhod 2 cosmonauts Belyayev and Leonov wore space suits because they were scheduled for the first space walk.

American space walks first took place during the Gemini program (see post 87). That craft had two hatches but no airlock; both astronauts were in vacuum during the entire spacewalk.

To exit his Voskhod in space, Leonov used an inflatable airlock (see drawing above), leaving Belyayev in the craft and unable to aid him. I had known this for several years but just in the last few days found out why. Russian electronics within Vostok and Voskhod were air cooled. American electronics were not. This meant that if a Voskhod were opened to space, the electronics would overheat.

On Voskhod 2, Leonov crawled into the airlock, sealed the inner door and opened the outer one. Belyayev remained in the pressurized descent module.

For ten minutes, Leonov remained within the airlock but exposed to the vacuum of space, then he slipped free and floated on a tether for another ten minutes. He was called back in to terminate his space walk, and his difficulties began.

(Or perhaps they had already begun. Some sources state that he “experienced a disorienting euphoria” during the space walk and other sources state that he suffered bends like symptoms after the space walk was over; I haven’t been able to confirm these statements.)

This post concludes on Thursday.

575. Textbook: The Rolling Stones

This is a continuation of the post Learning Spaceflight.

For someone reading this post today, it will require a bit of imagination to recreate the head space I’m talking about. Think 1952. Sub-divisions and interstate highways were brand new. NASA was still three years in the future. Heinlein wrote a science fiction juvenile called The Rolling Stones in the year Mick Jagger was still twelve years old.

In the interests of full disclosure, I was five years old that year, so I must have read it six or seven years after publication.

In those days, those of us who were in love with the idea of spaceflight were getting our fix from science fiction, and mostly from juveniles. PBS was seventeen years in the future, and NOVA was twenty-two years in the future.

I recently re-read The Rolling Stones. It was never my favorite novel. I would give it one star for plot and no stars for its obnoxious characters.

The Stone family lived on the moon. The slightly underaged twins wanted to buy a spaceship and flit around the system on their own, using money they had made from an invention. Dad said, “No,” but never fear. He bought a larger ship and took his whole family along, first to Mars, then to the asteroid belt.

If my tone sounds facetious, chalk it up to how irritating all the characters were, but as a textbook on how to fly in space, The Rolling Stones was top notch.

Here is an example. Leaving Luna for Mars, the Stones opt for the most economic orbit. This puts them in a long line of craft who have made the same decision. They fuel up on Luna then drop down to pass close to the Earth because . . .

A gravity-well maneuver involves what appears to be a contradiction in the law of conservation of energy. A ship leaving the Moon or a space station for some distant planet can go faster on less fuel by dropping first toward Earth, then performing her principal acceleration while as close to Earth as possible. To be sure, a ship gains kinetic energy (speed) in falling towards Earth, but one would expect that she would lose exactly the same amount of kinetic energy as she coasted away from Earth . . .

The mass of fuel adds to the energy as they drop deeper into the Earth’s gravity well, but the fuel is expended at perigee so it does not subtract from the energy as they move away. I’m interrupting RAH and explaining it myself because he took too many paragraphs, but that’s where I learned about gravity well maneuvers. By the time I got to college my main interest was ecology and then anthropology, so I never studied engineering or orbital mechanics. I still wish I could have done both but, in truth, most of my knowledge of space travel came from Heinlein, Clarke, Ley, and Goodwin, with lesser lessons from Gamow, Coombs, Hoyle and dozens whose names I no longer remember.

Later on, the Stones headed out for the asteroid belt. They . . .

shaped orbit from Phobos outward bound for the Asteroids six weeks later. This was no easy lift like the one from Luna to Mars; in choosing to take a ‘cometary’ or fast orbit . . . the Stones had perforce to accept an expensive change-of-motion of twelve and a half miles per second for the departure maneuver. A fast orbit differs from a maximum-economy orbit in that it cuts the orbit being abandoned at an angle instead of being smoothly tangent to it… much more expensive in reaction mass.

Of course. That makes perfect sense.

I watched the first part of a NOVA program the other day called The Rise of the Rockets. I turned it off about ten minutes in muttering kinderspiel. At least that’s the word I’m choosing to use in this family site. That happens a lot. NOVA covers fascinating subjects, but they tend to dumb them down. The old dudes did it better, even in their fiction.

However, they didn’t always get it right. Regarding the asteroid belt, RAH said . . .

But it was not until the first men in the early days of the exploration of space actually went out to the lonely reaches between the orbits of Mars and Jupiter and looked that we learned for certain that the Asteroids were indeed fragments of a greater planet — destroyed Lucifer, long dead brother of Earth.

Back in the fifties when The Rolling Stones was written astronomers had not yet decided if the asteroids were an exploded planet or an unformed one, caught in the tidal stresses of Jupiter’s gravity. RAH chose the more exciting option. Today we know better. Too bad. I always wanted to write a novel called The Last Days of Lucifer. I guess I still could, as steampunk.

In the fifties, we knew little about the universe and not all that much about the solar system. A lot of what RAH and others wrote has been killed by current knowledge. He had a non-human civilization with canals on Mars and intelligent talking dragons in the swamps of Venus. But he knew his math, and his rockets always got where they were going by following the rules of physics that NASA uses today.

574. Learning Spaceflight

I learned how to fly in space before spaceflight existed, from science fiction writers who, in turn, learned it from pioneers like Robert Goddard, Willy Ley, Herman Oberth, and Wernher von Braun. Or Tsiolkovsky in Russia. The pioneers’ tool was mathematics. They speculated, then looked at those speculations through the unblinking eye of calculations. They taught everyone how to fly in space long before NASA existed. Later some of them worked for NASA.

When I was researching for a post on Apollo Eight, I encountered reference to the barbecue roll. I had known about that maneuver from science fiction, long before Apollo Eight.

The barbecue roll is needed because vehicle in deep space is surrounded by vacuum with sunlight impinging on one side and sub-polar cold on the other. In low Earth orbit, that condition only lasts 45 minutes of every 90 minute orbit followed by pure cold in the Earth’s shadow. Apollo Eight was the first manned vehicle to endure that temperature imbalance on a long term basis — roughly five days. That’s a lot of stress.

The solution, used on Apollo Eight, then Apollo’s Ten through Seventeen, was to spin the craft about it’s long axis. It was called the barbecue roll, as in a rotisserie. You can hear that phrase used in the movie Apollo 13, and it will probably appear on the movie First Man when it comes out in October.

Anyone who had read any science fiction knows about spinning ships to provide artificial gravity. That’s not what we are talking about. The barbecue roll was quite slow, the distance from center of craft to skin was small, and any pseudo-gravity produced was probably imperceptible. The entire purpose of the roll was to equalize heat distribution by exposing all parts of the skin to heat, then cold, in sequence.

Long before there were real spacecraft, I had read about this maneuver in early science fiction, probably multiple times. It made me want to know who thought it up, which scientist first wrote about it, and how many decades before it was needed was it speculated into existence.

It struck me as a prime example of the kind of thing the pioneers did while they were writing the rules of the game, long before the game was ever played.

I looked for answers and struck out. I spent far too many hours reading the same few references on the internet, usually repeated without credit, or reading technical articles. The papers scientists and engineers write are long on facts, but short on history.

Somewhere, somewhen, somebody was dreaming about his imagined spacecraft out in a long orbit between the planets, and figured out how to equalize temperature. It might have happened several times independently. I would love to have been there, in the dormitory lounge of some engineering department, or in a meeting of enthusiasts at some model rocket club, or in the bedroom of some kid like Asimov in America or Clarke in Great Britain or some kid whose name I can’t even guess in Russia. What fun to be there when some nerd (before the word existed) slapped his head and said, “Hey, listen to this!”

Of course that moment in inaccessible, but somewhere, sometime, somebody wrote down his speculations in a paper that only enthusiasts would ever read. That is what I could have reasonably hoped to find. If you have any clues where I could continue the search, please reply to this post.

What I finally did find was one partial reference in Heinlein’s The Rolling Stones, quoted here:

The weather outside the orbit of Mars is a steady ‘clear but cold’; no longer would they need reflecting foil against the Sun’s rays. Instead one side of the ship was painted with carbon black and the capacity of the air-heating system was increased by two coils.

I clearly remember, from several sources, the notion of painting part of a vehicle black to better absorb solar energy as ships moved out further from the sun. One nagging memory has a ship painted with white and black stripes and spun. Heinlein did not spin his ship; he distributed heat to the cold side via refrigerant coils. In that particular novel, Heinlein had to maintain a non-spinning ship for plot reasons. In science fiction, physics start the ball rolling but plot determines where that ball ends up.

We’ll look closer at The Rolling Stones as a textbook for spaceflight within the solar system on Monday.