By Chip Neville, ’62
July 23, 2011
Published on Yale62.org Sept. 30, 2011
[Editor’s note: Why were the hopes and dreams of so many that by 2001 we would have human explorers on Mars and repeated trips to the Moon so far from the mark? Chip Neville, a PhD mathematician and close watcher of space affairs, has some ideas.
Also on our Yale62.org website by Chip Neville: NASA’s New Frontier and Human Space Flight Committee Report.]
I admit it! When it comes to rockets and dinosaurs, I’m still a kid. But it turns out that I’m in good company. A few days ago Dennis Overbye, the noted New York Times science correspondent, admitted that he was and is inspired by the science fiction of his youth, so I can admit the same, even though the science fiction I read was that of a generation previous to his.
On July 4, a few days before Atlantis lifted off for the last space shuttle mission, here is what Dennis Overbye wrote,1
“The shuttle was a big deal then (in 1981). But now, after 30 years of shuttle flights, the last mission ever is being prepped for its launching on Friday. Humans are no closer to the stars than before, and the space program is in tatters.”
He went on to reminisce about growing up with science fiction, where spaceships crewed by people went to other planets and the stars, and about how many in astronomy and the space program grew up similarly. He even quoted an astronomer “who grew up with the same science fiction dreams and expectations as I did (and) once described himself as a member of the ‘cheated generation.'”
Why have the hopes and expectations of so many, that by 2001 (not to mention 2011) we would have journeyed back to the Moon and Mars, been so far from the mark? Why have we had to be content with plucky robot Mars explorers? And what ever happened to the ion drives, evil talking computers and manned Jovian missions of “2001: A Space Odyssey”?2
There are three, possibly even four main reasons why our hopes and dreams have been disappointed:
First, we lack an adequate power source for our spaceships. In the science fiction of my youth, and Dennis Overbye’s youth, spaceships were nuclear powered. The best power source we have for the most difficult task in space travel, lifting out of the Earth’s gravity well into orbit, is chemical power. And chemical power, at least chemically powered rockets, just don’t cut it when it comes to economical space flight.
Second, we lack economic incentive. Although the space program has brought enormous economic benefits with communications satellites, weather satellites, reconnaissance satellites (useful for mineral exploration and resource monitoring as well as military reconnaissance), and GPS satellites, none of these involve travel beyond earth orbit. Indeed, a recent article in The Economist was subtitled, “Inner space is useful. Outer space is history.”3
Third, the Vietnam war brought a general revulsion towards science and a belief that it did not hold the key to the solution to our problems. It is no coincidence that the first human crewed planetary exploration program, involving the Saturn rocket and the Apollo spacecraft, came to an abrupt end as the war was winding down. We had the keys to the inner solar system with the Saturn V rocket, and we threw them away.
Today, we once again believe that science and technology hold the keys to our future, but this time the essential problems we must solve involve better energy sources here on Earth, not rockets to the stars. The technologies that we know we must develop are solar power, wind power, and better, MUCH SAFER nuclear power. It seems we have little money left over for human crewed space exploration.
This brings us to the possible fourth reason why the science fiction expectations of so many are now mere science fiction dreams, not worth pursuing. With all our problems here on Earth, we may have lost the will to explore. It is worth noting that the science fiction author Robert A Heinlein predicted this back in 1949, in his famous story, “The Man Who Sold The Moon.”4 A more telling historical example is provided by the voyages of the Ming Dynasty Chinese Admiral Zheng He, who explored the Indian Ocean before Vasco da Gama, and may even have sailed the Pacific and reached the New World before Columbus.5 But this effort was totally abandoned under the next Emperor, and “by 1500 it became a capital offense to build a seagoing junk with more than two masts.”6 Perhaps our Apollo and Space Shuttle Missions are like Zheng He’s voyages, but I hope not.
Is there a way to resurrect the manned space program? To do so, we need three things, economic incentive, better technology, and the will to explore. All of these are within our reach, if only we will (modestly, for funds are going to be tight from here on out) fund and grasp them.
Economic incentive will be key, and The Economist provided one view of the near future:7
“The future, then, looks bounded by that new outer limit of planet Earth, the geostationary orbit. Within it, the buzz of activity will continue to grow and fill the vacuum. This part of space will be tamed by humanity, as the species has tamed so many wildernesses in the past. Outside it, though, the vacuum will remain empty. There may be occasional forays, just as men sometimes leave their huddled research bases in Antarctica to scuttle briefly across the ice cap before returning, for warmth, food and company, to base. But humanity’s dreams of a future beyond that final frontier have, largely, faded.”
The Economist has the first part right. Servicing satellites, space telescopes, and the like will develop into an economically attractive proposition, provided the Federal Government continues to provide seed money and a guaranteed market. Now, when an expensive geostationary satellite runs out of rocket propellant to adjust its orientation, it must be abandoned. Geostationary satellites orbit much higher than the low Earth orbits of the International Space Station and the Hubble Space Telescope, and the Space Shuttle cannot reach them. But if a private firm could use the International Space Station (ISS) as a base to assemble a vehicle in low Earth orbit, a vehicle which could transit between the ISS and satellites in geostationary orbit, then it could refuel them. And this would save hundreds of millions of dollars. So activity in the volume of space between the Earth’s atmosphere and geostationary orbit will continue to grow.
What The Economist misses is that the technology to exploit this volume of space can, in principal, be harnessed to explore the inner solar system. But we will need to use better technology to do this effectively. Some parts of this technology exists and are in use today. Other parts must still be developed.
It turns out that the ion drives and talking computers of “2001: A Space Odyssey” are in use now. An ion drive powers NASA’s Dawn spacecraft which arrived at the asteroid Vesta on July 16.8,9 After exploring Vesta from orbit, Dawn will accelerate and travel to the asteroid Ceres sometime in 2015. The power source for Dawn’s ion drive is not nuclear as in “2001: A Space Odyssey,” it is solar. Dawn uses solar panels to provide the electricity to power its ion drive. This is safer than a nuclear power plant and much lighter.
With its ion drive, Dawn will be the first spacecraft to enter orbit around one celestial body and then leave to orbit and explore another. The first lesson we learn from Dawn is that solar is the way to go for serious interplanetary flight, once we have achieved low Earth orbit using chemical rockets. And the second lesson we learn is that the predictions of “2001: A Space Odyssey” were not that far from the mark.
Of course, Dawn does not carry a crew, and no human crewed interplanetary missions are currently on NASA”s agenda. But we can hope that crewed interplanetary missions using some form of solar power will be planned in the next decade.
As for HAL, the evil talking computer in “2001: A Space Odyssey,” we are not there yet, and maybe that is a good thing. But I spent 20 years teaching computer science at a small university in Connecticut, and I can tell you from personal experience that HAL has inspired several generations of computer scientists to pursue the dream of artificial intelligence. We now have computers that can talk to us and usefully respond to spoken commands, and artificial intelligence research has resulted in many transformative products, including such symbolic mathematics programs as Mathematica and Maxima. Computers even play chess better than most humans.10 So move over HAL, we can’t do you yet, but we are close. And with your dire example in mind, we will (I hope) be careful what we let your successors do.
The other incredibly influential science fiction work of the late 1960s was “Star Trek.”11 We have no idea how to design a warp drive, but “Star Trek” was set in the 23rd century, so perhaps we have time. However it is quite remarkable how many of the 23rd century gadgets predicted by “Star Trek” are available now:
Case in point 1: Talking computers. My 11 inch MacBook Air talks to me, and it is no larger than a writing paper tablet. (OK, it’s a bit thicker, but I can still stow it in my desk drawer as though it were a paper tablet.) While my MacBook is not quite as verbally versatile as the Enterprise’s computer, it is surely more portable.
Case in point 2: The Star Trek Communicator. My older model iPhone works as well as the Communicator and does much else besides. Also, it’s smaller and cooler looking. “Beam me up Scotty and I’ll show you a real Communicator.”
We are just beginning to get primitive versions of Dr. McCoy’s Scanner, and we don’t have any idea how to teleport anything larger than a few atoms, but these Star Trek dreams have inspired legions of scientists and engineers. For example, Dr. Kirk Shelley at the Yale Medical School has found a way of using the familiar pulse oximeter, the device that clips to your fingertip to measure your pulse and oxygen level, to non-invasively measure blood volume during surgical operations. He was, he says, inspired by “watching Star Trek’s Dr. McCoy in action.”12
If these two science fiction works, the movie “2001 A Space Odyssey” and the TV series “Star Trek” have been so inspirational, it is all the more remarkable that in almost every way other than space travel they were far too conservative in their predictions. For instance, they completely missed the microcomputer revolution, a revolution we are still in. My MacBook Air and your iPad are proof of how overly conservative they were.
But their predictions for space travel itself still have not been realized. We may well have to defer the interstellar travel of “Star Trek” to the 23rd century in which it is set, but to get to where “2001 A Space Odyssey” imagined we would be, we have to introduce some new technology:
1. Ion drives. Ion drives, also called ion thrusters, work by using an electric field to accelerating charged particles out the back of a spacecraft.13 Ion drives are already here, as the Dawn spacecraft shows. Problem: Ion drives are limited by the amount of power delivered to them, and current power sources don’t deliver much. (By contrast, conventional rockets deliver tremendous power and acceleration for a brief time but are limited by the total amount of propellant they carry.) Dawn’s solar panels provide relatively little power to Dawn’s ion drive, though they can deliver this power for months or years at a time. The result: spacecraft like Dawn accelerate very slowly. Dawn takes 4 days to go from 0 to 60 mph.14 So ion drives are good for interplanetary travel, but human crewed missions from low Earth orbit to geosynchronous orbit using ion drives may take too much time to be practical. Never-the-less, with development effort, and this is one of the things NASA should be doing now that the Space Shuttle program has ended, practical higher powered ion drives which could send astronauts from low Earth orbit to geosynchronous orbit in a few days may be possible.
2. Solar sails: Solar sails are large thin reflective films, usually made of mylar, which work much like ordinary sails, except that they get their push by reflecting sunlight back instead of deflecting wind backwards.15 Solar sails are here now and they work. The Japanese Space Agency launched a solar sail powered spacecraft, IKAROS, on May 21, 2010. It took the spacecraft 3 weeks to deploy its solar sail, after which it successfully cruised through interplanetary space, reaching Venus in 6 months.16 By interplanetary spacecraft standards, IKAROS was a speed demon.
Problems: Though solar sails can accelerate a spacecraft for months or years at a time like ion drives, they accelerate slowly. Also, they do not work at all in low Earth orbit due to residual atmospheric drag. So they are not a feasible propulsion method for traveling from low Earth orbit to geosynchronous orbit. However, they may be a practical method for traveling from slightly higher Earth orbit to geosynchronous orbit.
History: A private group, the Planetary Society, designed, built, and attempted to fly a solar sail powered spacecraft in 2005.17 (The Russian booster unfortunately blew up on launch.) The first serious design for a solar sail had appeared long before, in 1951 in the article “Clipper Ships of Space” in Astounding Science Fiction. To quote from the Planetary Society,18
“Then in May 1951 the leading SF magazine of its time, Astounding Science Fiction, published a detailed account of how solar sails could be assembled in orbit and used for space travel. The account was a nonfiction article, “Clipper Ships of Space,” by an engineer named Carl Wiley. Given that he published his article in a science fiction magazine, and wrote it under a pseudonym (Russell Saunders), Wiley himself apparently feared that respectable scientific circles were not yet ready for the solar sailing concept. It took another seven years for a paper on solar sails (by Richard Garwin) to appear in a professional journal, Jet Propulsion.”
I read and was inspired by a reprint of “Clipper Ships of Space” in Astounding as a boy.
3. Scramjets: A ramjet is a jet engine that dispenses with the turbine compressor stage of a conventional jet and instead uses the rush of incoming air for compression. A scramjet is just a ramjet that uses supersonic flow in the compression stage.19 Ramjets, where the incoming airflow is slowed to subsonic speeds, have been used in military missils for years. There have been military scramjet projects for years as well. They have been so shrouded in secrecy that no one knows which, if any, worked.
Problem: Temperatures in a scramjet rise very high very quickly. Scramjet powered test aircraft have reached high speeds, but the engines have melted after a few seconds or minutes. Though NASA has designed and tested scramjets, no one knows if the temperature problems can be overcome.
Advantages: Unlike conventional turbojets, scramjets can potentially achieve orbital velocity. And unlike conventional rockets, scramjets are air breathing, so they do not need to carry oxidizer for combustion. This saves a huge amount of weight. For example, “the space shuttle external tank holds 616,432 kg of liquid oxygen (LOX) and 103,000 kg of liquid hydrogen (LH2) while having an empty weight of 30,000 kg.”20 A scramjet powered shuttle could dispense with most or all of the 616,432 kg of liquid oxygen and use the saved weight for extra payload. Thus scramjets promise to make travel to low Earth orbit cheap and affordable, if they can be made to work.
By ending the Space Shuttle program, NASA has freed billions of dollars which could be used to develop some of this promising new technology. But NASA has a second important role to play: through its Commercial Crew and Cargo program, dubbed, with a nod to “Star Wars,” “C3PO,” it is providing seed funding and a guaranteed market for the private companies which are developing commercial systems to send cargo and people to and from low Earth orbit.21 We have to give credit where credit is due. The cargo part of this far seeing program stems from a January 14, 2004 directive to NASA from President George W. Bush,22 and the crew part was funded by Barack Obama with stimulus money.23 There is something here for people of every political persuasion, which is perhaps one of the reasons why we ought to continue to explore space. Unfortunately, Congress does not seem to understand this, and last year handed NASA a mandate to develop a new heavy lift rocket and space capsule which it can’t use and can’t afford.24,25 The money will have to come from, yes you guessed it, the C3PO program, which would have to be cancelled. In a time of budget austerity, we cannot let pork politics derail space policy.
Assuming the pork barrel politicians can be shamed into good behavior, the future of the C3PO program looks promising. SpaceX had a highly successful launch of its Dragon space capsule atop its Falcon 9 rocket on December 15, 2010. The rocket successfully inserted the Dragon capsule into orbit, and the capsule orbited the Earth twice before successfully re-entering and splashing down in the Pacific.26,27,28 SpaceX believes it can begin delivering cargo to the International Space Station (ISS) in 2012 and carry astronauts to and from the space station by 2015.
There are other companies in the competition to deliver cargo and people to the ISS, and one of them is designing the Dream Chaser, a small Space Shuttle like vehicle.29 So if all goes well, we may even have a space plane by 2015.
If private companies can reduce the cost of delivering cargo and people to low Earth orbit by, say, a factor of 2, can space taxi like vehicles shuttling people to and from low Earth orbit to geosynchronous orbit be far behind? And if they were powered by solar powered ion drives or solar sails, wouldn’t the inner solar system once again be within our grasp?
At the end of his New York Times piece, Dennis Overbye pessimistically says,30
“I no longer expect to see boot prints on Mars during my lifetime, nor do I expect that whoever eventually makes those boot prints will be drawing a paycheck from NASA, or even speaking English.”
I hope not, and I expect not, though we probably will have international crews speaking a variety of languages, just as in Star Trek, and just as on the sea today. As George Pal says at the close of his great 1950 movie “Destination Moon,”31 it is not the end, but
“The End of the Beginning.”
References.
1. “As Shuttle Era Ends, Dreams of Space Linger” by Dennis Overbye, New York Times, July 4, 2011, at
http://www.nytimes.com/2011/07/05/science/space/05shuttle.html
2. “2001: A Space Odyssey (film)” in the Wikipedia at
http://en.wikipedia.org/wiki/2001:_A_Space_Odyssey_(film)
3. “The end of the Space Age, Inner space is useful. Outer space is history,” The Economist, print edition, June 30th 2011, at
http://www.economist.com/node/18897425?Story_ID=18897425
4. “The Man Who Sold The Moon” by Robert A. Heinlein, copyright 1949. See the excellent Wikipedia article, “The Man Who Sold The Moon” at
http://en.wikipedia.org/wiki/The_Man_Who_Sold_the_Moon
and the detailed publication history, “The Man Who Sold The Moon,” at The Internet Speculative Fiction Database at
http://www.isfdb.org/cgi-bin/title.cgi?41176
5. “Indian Ocean and beyond” section of “Chinese exploration” in the Wikipedia at
http://en.wikipedia.org/wiki/Chinese_exploration#Indian_Ocean_and_beyond
6. “Indian Ocean and beyond” section of “Chinese exploration” in the Wikipedia at
http://en.wikipedia.org/wiki/Chinese_exploration#Indian_Ocean_and_beyond
7. “The end of the Space Age, Inner space is useful. Outer space is history,” The Economist, print edition, June 30th 2011, at
http://www.economist.com/node/18897425?Story_ID=18897425
8. “Dawn (spacecraft)” in the Wikipedia at
http://en.wikipedia.org/wiki/Dawn_(spacecraft)
9. “NASA’s Dawn Spacecraft Enters Orbit Around Asteroid Vesta,” NASA, at
http://cio.gsfc.nasa.gov/home/hqnews/2011/jul/HQ_11-231_dawn.html
10. “Computers versus humans” section of “Computer chess” in the Wikipedia at
http://en.wikipedia.org/wiki/Computer_chess#Computers_versus_humans
11. “Star Trek” in the Wikipedia at
http://en.wikipedia.org/wiki/Star_Trek
12. “Diving deep into a data wave to help make surgery safer,” Medicine @ Yale, May/June 2006, at
http://www.medicineatyale.org/v2i3_may_june2006/datawave.html
13. “Ion thruster” in the Wikipedia at
http://en.wikipedia.org/wiki/Ion_thruster
14. “Operational missions” section of “Ion thruster” in the Wikipedia at
http://en.wikipedia.org/wiki/Ion_thruster#Operational_missions
15. “Solar sail” in the Wikipedia at
http://en.wikipedia.org/wiki/Solar_sail
16. “IKAROS” in the Wikipedia at
http://en.wikipedia.org/wiki/IKAROS
17. “Partially successful solar sail propulsion tests” section of “Solar sail” in the Wikipedia at
http://en.wikipedia.org/wiki/Solar_sail#Partially_successful_solar_sail_propulsion_tests
18. “Projects: LightSail – Solar Sailing, Solar Sails in Science Fiction,” by Alan C. Elms, The Planetary Society, at
http://www.planetary.org/programs/projects/innovative_technologies/solar_sailing/science_fiction.html
19. “Scramjet” in the Wikipedia at
http://en.wikipedia.org/wiki/Scramjet
20. “Propellant” section of “Scramjet” in the Wikipedia at
http://en.wikipedia.org/wiki/Scramjet#Propellant
21. “Commercial Crew and Cargo,” NASA, at
http://www.nasa.gov/offices/c3po/home/index.html
22. “NASA Invests in Private Sector Space Flight with SpaceX, Rocketplane-Kistler,” NASA, August 18, 2006, at
http://www.nasa.gov/exploration/news/COTS_selection.html
23. “Commercial Crew & Cargo,” NASA,
http://www.nasa.gov/offices/c3po/partners/ccdev_info.html
24. The New NASA Plan For Human Space Exploration,” Planetary Society Space Advocacy page, June 15, 2011 at
http://www.planetary.org/programs/projects/advocacy_and_education/space_advocacy/
25. “NASA: New rocket not feasible with current budget”, CNET News, January 13, 2011 at
http://news.cnet.com/8301-19514_3-20028482-239.html
26. “SpaceX’s Dragon Spacecraft Successfully Re-enters from Orbit”, SpaceX Corporation, December 15, 2010, at
http://www.spacex.com/updates.php.
At some point this link will expire and you will have to look on the past missions page at
http://www.spacex.com/past_missions.php
27. “SpaceX hails ‘mind-blowingly awesome’ test flight” by William Harwood, CBS News, December 8, 2010, at
http://www.cbsnews.com/network/news/space/home/spacenews/files/b7f497e4aa85d103f0d6d9a8dd704a6f-126.html
28. “Is SpaceX the new NASA?” by Erica Hill, CBS News Video, July 20, 2011, at
http://www.cbsnews.com/video/watch/?id=7373909n&utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+CBSNewsPolls+(CBS+News%3A+Opinion%3A+CBS+News+Polls)
29. “Private firms race to make return to space” by Mark Strassmann, CBS News, July 18, 2011, at
http://www.cbsnews.com/stories/2011/07/18/eveningnews/main20080485.shtml
30. “As Shuttle Era Ends, Dreams of Space Linger” by Dennis Overbye, New York Times, July 4, 2011, at
http://www.nytimes.com/2011/07/05/science/space/05shuttle.html
31. “Destination Moon (film)” in the Wikipedia, at
http://en.wikipedia.org/wiki/Destination_Moon_(film)
and “Destination Moon (1950)” at the Internet Movie Database at
http://www.imdb.com/title/tt0042393/
Notes:
1. Document dates are web page dates. For example, the actual print edition of the Economist appeared on July 2, 2011, not June 30, 2011. Exceptions are copyright dates and film dates.
2. College professors generally discourage quotation from the Wikipedia. However, though the Wikipedia can be dramatically wrong, most of its articles are more accurate than those in conventional encyclopedias like the Britannica. And I know from my own knowledge that the particular articles quoted here are very good indeed.
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Karl, I agree with you about the advantages of robotic explorers, and I agree they are extensions of ourselves. But humans are far more adaptable, and can do in a few minutes what robots may take hours or days to do. Consider, for example, the repairs to the Hubble Space Telescope made by human astronauts. I believe we need both, robot explorers and, ultimately, human explorers.
This hiatus in funding for manned missions is a time to build ever-better robotic surrogates through which, as extensions of ourselves, we explore more of our solar system. Unmanned missions are not doing things in our place — we act through them, with the huge cost advantage that the vehicles do not have to be engineered to meet the requirements of human-rated systems.
I’m working now under a contract with NASA to verify the flight software (developed by JPL (Jet Propulsion Laboratory) for science missions — not manned spaceflight. These missions continue and in them, we advance our technology , despite the end of the shuttle missions, and despite the cancellation of the Constellation program (the Ares rocket and Orion CEV (Crew Exploration Vehicle, on which I worked for a few years) and I see each such missions advancing human capabilities for robotic exploration.
It would be nice to know how many of our classmates have participated in Space related activities. I only know one. The late Lew Elsey was one of the frogmen who jumped from a helicopter into the Pacific Ocean to retrieve one of the early capsules. Does anyone have pictures?