Like many red-blooded American teens coming of age during the 1960s space race, Franklin Chang-Diaz dreamed of chasing cosmonaut Yuri Gagarin to the stars.

There was a hitch, of course. Chang-Diaz wasn't American. He lived outside the United States. And the Costa Rican didn't even speak English.

No matter. Chang-Diaz would overcome these obstacles and more to fly a record-tying seven missions aboard the space shuttle. Along the way the physicist would also develop a plasma rocket that promises a revolutionary approach to spaceflight.

The rocket, potentially, could blast the next generation of astronauts to Mars in just 39 days, about one fifth of the time required by existing rocketry.

At a time when much of Houston's space community is openly hostile to President Barack Obama's desire to remake NASA's human spaceflight program, Chang-Diaz, 60, is among those welcoming it.

“Even though this transition is very strong medicine, and it is being applied at a very awkward moment, it is the right thing to do,” he said.

From his perspective, if humans are ever to venture substantially beyond Earth's moon, they'll need advanced propulsion systems to do so.

And the sooner NASA begins reinvesting in them — funding for advanced propulsion dried up in 2005 when money was diverted into the Constellation program to build conventional rockets to send astronauts back to the moon

— the better, says Chang-Diaz, whose Clear Lake rocket company, Ad Astra, could profit from such a change.

On Thursday, in a speech to promote his space policy plans, Obama confirmed that it will take new technologies for NASA to explore deeper into the solar system.

“We've got to do it in a smart way,” he said at Kennedy Space Center in Florida. “We can't keep doing the same old things as before.”

One-way ticket to U.S.

Chang-Diaz's story begins in a San José bank, where he worked as a teller after graduating from high school to scrabble together enough money to come to the United States. After nine months Chang-Diaz had saved $50 and convinced his dad, a construction foreman, to buy him a one-way ticket to America.

In 1968 he arrived in Hartford, Conn., to stay with distant relatives. Not speaking English, he enrolled in a local high school to learn the language and, in time, apply to college.

“Of course it was a disaster,” Chang-Diaz recalled. “The first marking period I failed everything. But from being at the bottom I began to improve, and towards the end of the year I was near the top of the class.”

So promising a student was he that Chang-Diaz earned a partial scholarship to the University of Connecticut. He sailed through college and, later, graduate school at the Massachusetts Institute of Technology, studying mechanical engineering and physics, with an interest in plasma, an electrically charged gas that responds to electromagnetic fields.

By 1979, Chang-Diaz was a citizen, and NASA was seeking scientists for its new space shuttle program. In 1980, he became NASA's first Hispanic astronaut, moved to Houston, and six years later launched aboard Columbia.

“I flew on all of the space shuttles,” he said. “I flew on Mir. I flew on the International Space Station. I just got to experience everything. Having come from a little country in Central America, sometimes it's amazing for me to even believe.”

How to get to Mars

Yet even as he flew into orbit, Chang was wondering how to get to Mars.

Between flight training he built a research team to begin work on a plasma rocket, drawing upon NASA engineers and scientists from across the country.

At their essence, rockets are simple: the higher the temperature of the gas shot out the back, the faster the gas and rocket go. Plasmas get hotter than conventional chemical rocket fuel, allowing plasma rockets to go faster on much less fuel.

Over the past three decades, Change-Diaz's group worked on a rocket that could convert hydrogen to a plasma, confine it with a magnetic field and then heat it with radio waves. From 1993 to 2005 he did so as director of the Advanced Space Propulsion Laboratory at the Johnson Space Center.

Then came Constellation, a program also managed in Houston.

“NASA decided to cancel all of its advanced propulsion and power programs in order to finance Constellation, which basically was a repeat of the Apollo program,” Chang-Diaz said. “So we were going to do the Constellation Program and go to the moon. Then what? You can't go to Mars with the Constellation hardware.”

Chang-Diaz decided to leave NASA after 25 years, taking with him his Variable Specific Impulse Magnetoplasma Rocket (VASIMR) technology. He formed the Ad Astra corporation in Webster.

His agreement with NASA allowed him to continue developing his rocket with private funding. He has raised tens of millions of dollars.

Since he left NASA, Chang-Diaz has quadrupled his VASIMR rocket's output to 200 kilowatts, a level sufficiently powerful to propel a spacecraft.

Testing by 2014

If the company can overcome the technological challenges, Chang-Diaz has a deal with NASA to fly his rocket on the space station by early 2014, testing it in space and possibly using its thrust to re-boost the station's altitude.

“It's an exciting technology,” said Mike Suffredini, manager of NASA's space station program. “Testing this kind of thing is exactly what the space station is up there for.”

If successful, Chang-Diaz sees a wealth of possibilities for VASIMR, including the refueling, repair and re-boosting of thousands of satellites orbiting Earth.

Mars remains a distant but tangible goal, requiring a more powerful, larger engine. Perhaps the biggest challenge is the cumulative radiation exposure for astronauts during long travels in deep space.

“All of a sudden we are at the right place at the right time,” Chang-Diaz said. “The whole premise that created the company in the first place five years ago is playing out. We're providing a more mature technology to NASA, and they haven't paid a dime.”

eric.berger@chron.com