You might expect to find our brightest hope for sending astronauts to other planets in Houston, at NASA's Johnson Space Center, inside a high-security multibillion-dollar facility. But it's actually a few miles down the street, in a large warehouse behind a strip mall. This bland and uninviting building is the private aerospace start-up Ad Astra Rocket Company, and inside, founder Franklin Chang Díaz is building a rocket engine that's faster and more powerful than anything NASA has ever flown before. Speed, Chang Díaz believes, is the key to getting to Mars alive. In fact, he tells me as we peer into a three-story test chamber, his engine will one day travel not just to the Red Planet, but to Jupiter and beyond.
I look skeptical, and Chang Díaz smiles politely. He's used to this reaction. He has been developing the concept of a plasma rocket since 1973, when he become a doctoral student at the Massachusetts Institute of Technology. His idea was this: Rocket fuel is a heavy and inefficient propellant. So instead he imagined building a spaceship engine that uses nuclear reactors to heat plasma to two million degrees. Magnetic fields would eject the hot gas out of the back of the engine. His calculations showed that a spaceship using such an engine could reach 123,000 miles per hour—New York to Los Angeles in about a minute.
All astronauts have big dreams, but Franklin Chang Díaz's dreams are huge. As a college student, as a 25-year astronaut and as an entrepreneur, his single animating intention has always been to build—and fly—a rocketship to Mars. "Of course I wanted to be an astronaut, and of course I want to be able to fly in this," he says of his plasma-thrust rocket. "I mean, I just can't imagine not flying in a rocket I would build." And now he's close. In four years Chang Díaz will deploy his technology for the first time in space, when his company, aided by up to $100 million in private funding, plans to test a small rocket on the International Space Station. If this rocket, most commonly known by its loose acronym, Vasimr, for Variable Specific Impulse Magnetoplasma Rocket, proves itself worthy, he has an aggressive timetable for constructing increasingly bigger plasma-thrust space vehicles.
Chang Díaz describes his dreams in relatively practical terms. He doesn't intend to go straight to Mars. First he will develop rockets that perform the more quotidian aspects of space maintenance needed by private companies and by the government: fixing, repositioning, or reboosting wayward satellites; clearing out the ever-growing whirl of "space junk" up there; fetching the stuff that can be salvaged. "Absolutely, fine, I'm not too proud to say it. We're basically running a trucking business here," he says. "We'll be sort of a Triple-A tow truck in space. We're happy to be a local garbage collector in space. That's a reliable, sustainable, affordable business, and that's how you grow."
Such a belief may seem overly ambitious, but the goals of aviation have always seemed that way. In October 1903, for instance, astronomer Simon Newcomb, the founding president of the American Astronomical Society, spelled out a series of reasons why the concept of powered flight was dubious. "May not our mechanicians," he asked, "be ultimately forced to admit that aerial flight is one of the great class of problems with which man can never cope, and give up all attempts to grapple with it?" Less than two months later, the Wright brothers flew at Kitty Hawk. And in the 1920s a young man named Frank Whittle was coming up with drawings for a theoretical engine very different from the propeller-driven kind, one that might scoop in air through turbines and fire it through a series of "jet" nozzles. "Very interesting, Whittle, my boy," said one of his professors of aeronautical engineering at the University of Cambridge. "But it will never work."
tommym, I believe there is quite a bit of radiation in space already. We do happen to have a totally unshielded fusion reactor hovering somewhere near the center of our solar system.;) Also, it is believed that we have a super-massive black hole at the center of our galaxy, which most likely is spewing out x-rays and other forms of radiation.
The concern about accidentally spreading radioactive material around the globe, should a space launch go wrong, is valid and unfortunately has happened before. However, I'm sure that hasn't stopped NASA or the US military or the Soviet Union from launching significant amounts of nuclear material into orbit. While I'm sure it's not exactly routine, I'll bet we know how to push a few pounds of nuclear material into space with a reasonable degree of safety.
Congratulations to Franklin Chang Diaz and good luck with this exciting project.
@tommym "But what about the safety of the aliens?" Did you seriously just turn all environmentalist about aliens that we're not even sure exist? That's gotta be a first, not to mention the looniest species-protection argument ever made. If there are even any aliens where we're going at all (and there's obviously no guarantee of that), it's not like we're talking about dropping nukes on another planet here. Nor would the propulsion system be pointed directly at the planet, anyway - it'd be facing the other way.
As for the risks involved, why do you the guy is proposing to gradually test the engine type on a smaller scale first? It's not like he's suggesting that he wants to just build the full-scale Mars exploration rocket right off the bat. There are always risks involved with every new technology, but scientists with brains, like Diaz, don't let that stop them. They just keep improving their inventions until the risk is minimized to an acceptable level. I, for one, hope he gets his design to that point soon, because all of mankind could stand to benefit as a result. Go for it, Diaz!
a nuclear explosion going off in the upper atmosphere would be one of the worst things that could happen to the planet
sometimes it pays to go towards the direction of science fiction. otherwise you either take tiny incremental steps that get you nowhere in a hurry or you get the budgetary ax or political ax.
to the person who asked about antimatter it is just on the edge of possibility and if you could get enough of it and store it safely it will heat the exhaust gas far more powerfully. in fact it is the only known way to get significant payload to relativistic speeds necessary for interstellar travel. fusion won't do it nor will nuclear fission augmented gas or plasma rockets. and light sails or beamed propulsion isn't exactly feasible either for a number of reasons. at least not for interstellar travel. maybe inside the solar system.
the first problem; where to get it or make it is yielding to progress now. initially the PAMELA probe confirmed only small amounts in the upper atmosphere. however the measurements have subsequently been greatly upgraded. and that does not count particles of it around other planets with atmospheres or near the sun. also progress has been made on technology to generate it on earth.
the second problem essentially how to keep it from accidentally blowing up; may be solved by forming it into neutral anti-hydrogen and then freezing it into a solid or slush and then using dimagnetism to suspend it in vacuum chambers. this renders it much safer (relatively speaking) than traditional magnetic schemes and does away with erosion of the vessel walls by straying particles. Magnetic traps always leak if they are used to contain gas or plasma. with antimatter ice in a vacuum there are far fewer stray particles.
these vacuum chambers should be small with fail safes for the dimagnetic suspension, vacuum pumps, and cryogenics systems and be ejectable in the event of imminent failure of those systems. each chamber should have independent containment cooling and vacuum systems so that failure of one chamber does not result in an annihilation reaction of all the stored antimatter in all the others. a pusher plate and separation collar should be between the fuel area and the rest of the ship so that a catastrophic failure of containment hopefully pushes the crew section away from the blast in the event of containment failure.
and to the guy worried about irradiating aliens...
well lets just talk abotu the technical reasons why that isn't a problem for either Chang's invention or for that matter most of the other schemes using nuclear reactors indirectly like VASIMR and closed system fission nuclear rockets.
the radiation is in the reactor and the propellent travels through the reactor to pick up heat. the radioactive stuff is not mixed with the exhaust. radioactive stuff could only be released if the rocket blew up or broke apart. VASIMR uses the power generated by the reactor to power the VASIMR magnets and plasma heating.
now it is true that more advanced nuclear concepts which produce higher specific impulse and delta V's do mix the propellant with the nuclear stuff and they should never be considered as a means to get something off the earth's surface.
ok, now as to your objections to irradiating aliens you are aware that all the elements we have (except a tiny bit we make ourselves) beyond helium come from stellar explosions. this includes BTW uranium and plutonium so there are billions and billions or trillions of massive radioactive engines of alien destruction and genocide going on all the time. poor aliens.
a nuclear explosion in the vein of nuclear bomb like explosions are impossible in a reactor. thats called a super critical reaction and it takes a lot of special effort to generate that. firstly the nuclear material must be enriched to bomb grade which is significantly higher than the grade used in reactors. secondly to get enough neutrons hitting nuclei the fissile material must be machined to the perfect spherical shape. then there must be enough fissile material in the sphere of material to maintain the reaction long enough to get explosive amounts of matter energy conversion. in the case of fusion bombs there must be a properly shaped special explosive packed around the plutonium pit. these must be detonated in precisely the correct timed sequence to start an even inward compression of the nuclear pit. without tritium doping the amount of plutonium must be much larger than what would be required for a modern weapon and presumably for the little rods or balls of stuff used in a reactor.
none of these conditions exist in a reactor and therefor a reactor going wrong on the way to space cannot blow up like a nuclear bomb. so no EMP. what could happen is the nuclear material could be dispersed in the atmosphere and present a mutation and cancer hazard for people in the fallout zone. but it is not a planet killer. when nuclear bombs were being tested several atmospheric and open ground and oceanic explosions occurred. Though i would not recommend exploding bombs like that we are still around, the world is not lifeless and we don't have eyeballs in the center of our foreheads.
I just read an article about small thorium reactors. could those potentially be used in conjunction with Chang's design? if by small they mean compared to today's reactors (by orders of magnitude), then install a couple or few of these thorium reactors. I'm not speaking from an experts point of view, but from my vast and ever expanding desire to see mankind finally reach another planet. im so proud to be living in an age where when people talk about this subject, it's not merely the plot for an episode of a sci-fi show...
Hahah that's hilarious, mournblade is the only person on here that makes sense. d:
"This article doesn't propose anything to do with a space elevator. So why ask?"
Articles like these generate discussions of the hypotheticals surrounding the topic. I thought his mentioning the elevator was a fabulously inventive solution to the problem of how to safely get a nuclear reactor into orbit.
Combining all of this theoretical stuff into something tangible is a great way to imagine how moving forward might solve out problems. Just because none of these things actually exist in a useable form, doesn't mean it isn't interesting to speculate about the solutions.
I thought his comment was thought provoking, which is why I take issue with your cynicism.
The people that keep talking about a nuclear explosian in orbit don't know anything about nuclear reactors or bombs.
a nuclear bomb requires an enrichment of about 90% and a nuclear reactor runs on about 3%. What can happen is it can get REALLY hot, but you will not get a EMP blast. Chernobyl, 3 mile and Tokyo were not consumed in a nuclear firestorm then neither would the spacecraft. Also if it does explode in orbit its because someone intended it too... with a bomb. Due to the mechanics of a nuclear weapon. Which requires the material to reach critical mass. and the typical fuse devices don't even work like the chemical weapons you're all relating it too. A nuclear weapon has to be armed to detonate. Just like a nuclear reactor has to be started in order to create energy which he clearly states they would not do until in orbit which is the only place his rockets work. Therefore, the reactor would be creating very little heat if any at all so your concerns are generally unfonded with the risk however of the rocket exploding and having the debris raining in your backyard or worse N. Koreas backyard. Howerer im sure Mr. Un would just create a plutonium toilet seat out of it or something.
hmm mournblade already said wat i said... oh well.