Posted on 11/07/2001 2:35:31 PM PST by RightWhale
Propulsion Isn't Just Everything, It's The Only Thing
by Rick Fleeter
Washington - Nov 6, 2001
The rest of the article:
What makes space the playground of people who share my love of frustration, who need a rather large synaptic gap between their own world view and reality? Is it the surely bonds of earth, the lure of the stars, and the need to be at one with the Infinite? Unfortunately, it's much easier than that. It is propulsion.
Maybe everything I know I learned from people sitting next to me on trains and planes and chairlifts. I made a three-hop semi-cross-country value priced trip on Southwest seated next to a pot bellied, red-nosed WWII vet with a visor cap from the 50th reunion of whatever ship it was he spent the war aboard. I tried to do the math - he seemed too old to have fought in WWII - career grunt, I reasoned. He told me, speaking of flights with lots of stops (who was?) about his first cross country flight on a DC-3. As a guy with lots of hours in propeller planes, many of them with 2 radial engines, his story of 3 hour hops covering maybe 250 miles, spliced together to reach Los Angeles, created sympathetic flying symptoms in me - particularly, sore ear drums. In those days, flying cross country was faster, but in all other senses worse, than taking a train or bus. The future of flying for any applications other than carrying mail across the Andes or fighting wars was cloudy - airplanes were slow, noisy, small (and hence uneconomical), dangerous and subject to every inch of weather between departure point and destination.
The jet engine changed all that. Suddenly we could carry hundreds of people aboard a flight, move them at nearly the speed of sound, through the mostly weather-free atmosphere at 38,000 feet, all the way across the country, or the Atlantic or Pacific, non-stop. Now we take for granted plenty of spare power for pressurization of the cabin, for deicing the wings with ample bleed air, for running movies and for carrying mail, freight, luggage and even toilets equipped with 110 VAC for razors. We have power to heat meals and coffee, power to run weather radars and lots of fancy avionics which make the flight even more safe and efficient. Look at the best propeller planes of today - they are still noisy, slow, fly low and weather affected. They are inferior even to a high speed train, now that rail has transformed itself by switching to electric vehicles instead of steam or Diesel.
Propulsive power even more radically changed road transportation, and the lives of nearly every person on the planet. People walked and rode horses for tens of thousands of years - until the automobile. Suddenly we could travel 100 times farther in a day, on our own, in air conditioned comfort, without care and feeding of a horse. We can carry an entire family and its luggage cross country in a few days. A city 50 miles across, like LA or New York, is not only conceivable - it's common around the world. We have buses and trucks hauling huge quantities of people and materials. It's such a fundamental feature of modern life, so vital to everything we do as human beings, that we can't even conceive of life without motorized cars, trucks and buses to carry us and our voluminous and heavy stuff around.
Motive power is fundamental to transportation, and a lot of other things. Lithium Ion batteries plus power saving electronics and software have given us cell phones and laptops that are slim, lightweight and run for hours. Without fuel cells, we wouldn't have reached the moon. Electric rockets are propelling missions like Deep Space - 1, and enabling a new class of more capable geosynchronous satellites. Change the propulsion system, and you change the game - not just by a few percent - you change the paradigm.
Paradigm changing is definitely what space transportation needs. Just as jet aircraft have now plateaued in speed, range and economy, with minute percentile changes from model to model, rockets aren't getting any cheaper, or any more reliable. With transportation costing upwards of $10,000 per kg - and many times that for smaller rockets, even very modest space missions - like putting five people on the space station with everything they need for a week's space vacation - is ridiculously expensive. A good number would be - $100M. Maybe $500M if you transport that family of five into orbit via the Space Shuttle. Taking three people to Mars with the stuff they need to stay a few days and return to earth is going to cost, just in transportation, possibly $10B - not including the cost to develop the rockets in the first place. Including that, maybe it's $100B. Nobody spends $10B on a rocket without making sure they are launching something valuable on top of it, ensuring that the cost of any space mission beyond LEO, rocket plus its payload, including humans, is going to absorb something like the GNP of a moderate sized country for many years. And in so doing, what will we have accomplished? Another one-time, bank account breaking stunt? The few billion rest of us will watch it on CNN.
Hence the romantically scintillating mismatch of the space groupie with the object of her or his affections - space travel, exploration, habitation and tourism. With our current dinosauric propulsion systems, sustained development of extraterrestrial destinations is as realistic as a bicoastal marriage in the era of the covered wagon. The mismatch is so exquisite, that all of us in our industry are drawn as moths to the light of the rocket plume. The very cost and complexity, the near impossibilty, of space transportation using chemical rockets, attracts our breed of tough minded, soft hearted space-niks. NASA and the USAF spend billions on attempts, mostly futile, to lower launch costs using chemical rocketry. Papers are written on space tourism and books on doing Mars on the cheap. Societies are started to promote space travel for everybody, and even exciting conspiracy theories are hatched about NASA and the space community purposely maintaining exorbitant transportation costs to reserve the realm of space just for their greedy selves, and / or to ensure big profits for aerospace contractors.
The vast gulf between the reality of propulsion and what is necessary to realize our vision of space enables us all to march forward every day as bold visionaries - some might say kooks - focused on a future practical people can't envision. We pity them, chained to earth by their practical nature. How boring it would be to admit that all of these space visions are completely feasible with better propulsion. Space transportation priced closer to $10/kg would make construction of space hostelries practical - conceivable by normal business people focused not on a future only possible in science fiction, but by short term return on investment. The ability to accelerate to a significant fraction, say 10%, of the speed of light would make visitation to all the solar planets a routine and daily phenomenon, not much more exotic than riding a bathysphere to a mid-ocean rift. The moon would become not (just) a vast laboratory for space scientists, but a playground for adventuresome tourists, maybe a place to get a break from the grind of life in 1-g without the discomforts and limitations of on-orbit life. On the moon, you could go for a drive, and even go wandering by foot around the surface, play golf, wearing a pressure suit, of course. With time the pressure suits would improve and travelers would buy them in ancitipatory excitement, as triathletes now buy yellow wet suits for their open water swims.
The space community is engaged in a valiant, gallant, exciting, but ultimately tragic and futile, battle to garner that next huge hunk of government money to do the next nearly impossible and definitely pointless trick in space. We planted a few people and their gear on the moon for a few days a few decades ago. Among Skylab, Mir and Freedom, we've managed to house a few people in orbiting platforms for a few days, weeks or even a year or so, at tremendous expense. And maybe one day, if we are ever so rich and so at peace and so bankrupt of better ideas, or alternatively so paranoid of being out-done by our rivals, we'll put two people on Mars to repeat the Apollo experience at 100 times the distance and expense. Exhausted and broke from the experience, we will retreat to Earth and maybe low earth orbit, for 10 or maybe for 100 years. The average person will, after all that time, money and politiking, be no closer to experiencing space than we were in 1965.
There is an alternative - another way. It is unromantic, unappealing to the visionary believers and elitists that see space in ways the rest of us, rooted in our mundane practicality, cannot. It is difficult, arcane, intellectually challenging and impossible to map into the future in any orderly way. It is expensive, but not nearly so expensive as the futility of trying to take inappropriate propulsion systems ever farther from earth on ever slimmer margins at ever larger budgets spread over ever longer program durations.
This alternative is to invest aggressively in propulsion. God may have given us hydrogen and oxygen, but She gave us a lot more stuff. Photons, Ions, subatomic particles, matter and anti-matter, field interactions, ramjets and interplanetary and interstellar materials to fuel them, including the solar wind. Carbon matrix structures for building a Jacob's Ladder to GEO. Frankly, as a chemical rocket guy, I have no idea which if any of these might ultimately make travel to orbit as commonplace as the Metroliner to Boston, or accelerate us to 0.1c for $10/kg. But what I do know, as a chemical rocket guy, is that hydrogen and oxygen, or any other simple chemical bond breaking and making rocket, won't, any more than coal, anthracitic, bituminous or otherwise, was going to take us from LA to Tokyo in 9 hours, or horses would build the America of the 21st century with its great cities, its suburbs and its clean streets.
The good news is that the human spirit will not, contrary to enthusiastic and dire warnings to the contrary, be extinguished should we abandon our Quixotic reach for the stars armed with rockets suitable at best for brief, barely exoatmospheric excursions. If we embark on a well funded, broad-based, long range program to revolutionize space propulsion, the space groupies will still meet in their space societies, still gripe, even louder, about our stubborn lack of will to go where no person has ever gone before, and still see a future that most of us can't. The coyote will still bay at the full moon, and teenagers will fall in love across racial, financial and cultural boundaries. Nothing much will change in our world, except that if we stay that course, humans will one day master a new technology - as fundamental as electronics - a sustainable, practical, readily available, economical means for everyone to experience space first hand, to bring it literally as close as the next town down the interstate, to occupy the moon and planets, and to travel even to other stars. And that's a bigger change than any of us can today envision.
(flame away - but...oh nevermind, you wouldn't believe me anyway)
So just killing NASA is probably not the way to go at this point. I want to see some private sector activities before that happens.
I have no doubt that improvements will continue as usual.
--Boris
This is nonsense. I call it the "Twilight Zone" argument.
What you are positing is that some all-powerful Galactic Federation has placed us "off limits". Maybe even patrolling outside the orbit of Pluto to enforce the Prime Directive.
If one assumes that there are many intelligent space-faring civilizations, it is more-or-less certain that one or more of them would give the finger (or tentacle) to the would-be game wardens. If several did, eventually one would get through, land on the White House lawn, and ask to meet the interns (they get the political news a little late).
Even less probable is an all-powerful Galactic Empire which enforces such prohibitions.
--Boris
Depends. Nuclear thermal rockets are superior. 800 to 900 "seconds" of specific impulse. Superior "performance".
But look at the thrust-to-weight ratio:
Nerva/Kiwi/Phoebus never got much above 7.5 thrust-to-weight. The SSME is ~70 in thrust-to-weight. Some of the expendible engines designed in the 1960s were close to 100 thrust-to-weight.
Even the "Timberwind" nuclear engine was only about 10:1 thrust-to-weight.
That's why nuclear thermal rockets are not good for boosters; they are simply too heavy--not to mention the danger of launching an operating reactor from the ground. The abort scenarios alone are horrifying.
But for in-space applications, where raw Isp matters more and thrust-to-weight matters less, they would be great. You can launch the reactor "cold" and with the reflectors retracted. In such a condition you could go up and hug it without fear of radiation. Once you turn it on, it is "hot" and therefore dangerous. Indeed, disposal of the engine once you reach your destination or return home is a big issue. The "obvious" solution--dropping it into the Sun-- is too costly in terms of Delta-Vee, reaction mass, and $$$.
Plus, the eco freaks would riot, protesting our wanton pollution of the Sun.
--Bors
Dear boris,
Thank you for contacting My customer service department. The answers to your questions are:
1. Because I'm bigger than you, and because I could, but don't forget about sub-atomic particles and stuff like that.
2. The prototype was designed to live forever but you can see what kind of problems that would cause now. Just imagine what it would be like with people like Bill and Hitlery Clinton living forever, or at least for very long periods of time. They would just be roaming around the earth like vampires or something and you just couldn't get rid of them.
Hope that helps.
Sincerely,
God
The second is how we will go there.
The third is what we will do when we get there.
When and why might also be of interest.
WOW! And you think the EPA has issues with nuclear!?! Wait until they get a hold of this idea! :)
Even an athiest can conceive of such a being.
So God exists--at least in the imagination.
But I can conceive of a still greater being. This being is not limited to existing only in the imagination. Among His attributes is existence in reality. Surely a being who cannot exist in reality is not greater than one who can.
Therefore one of the attributes of God--a being greater than which no other can exist--is existence in reality.
What is the flaw in this argument?
Hint: I got an "A" in my Philosophy 101 exam, so I know the answer.
I believe in God. But man has constructed myriads of fallacious "proofs" of His existence.
--Boris
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