As NASA’s leaders work to transform the Vision for Space Exploration into real programs, they are sure to be besieged with advice drawn from history. While history does have something to teach us, we have to be cautious in applying its lessons. We are all, at times, guilty of selectively reading history to fit our own ideas instead of making sure we are drawing the most applicable lessons, whether we like them or not.

There are two areas in which history is being quoted in the service of the vision. One is the history of exploration: Admiral Zheng’s Chinese treasure fleet and the voyages of Columbus and Cook are among the frequently used examples. The other is more specific: the history of space exploration and its examples of success and failure.

Virgil is credited with the motto, “Audentes Fortunas Juvat,” a maxim most commonly translated as “Fortune Favors the Bold.” History tells us that fortune does favor the bold. People are like nations: those who never look beyond the horizon inevitably recede from it, eventually into nonexistence. History also tells us, however, that disaster favors the too bold. Ask Amelia Earhart, or the people who pushed the Apollo program too fast before the lethal fire of January 27, 1967.

The right degree of boldness depends on both the nature of an enterprise and the challenges involved. It is true that explorers sailing their ships into the Pacific and those landing on the Moon both needed courage and vision, but it’s equally true that the former didn’t need to bring an atmosphere. There is more to learning from history than simply trying to repeat past formulas for success.

In search of relevant history lessons, it is logical to look first at previous human space efforts. Apollo, which was really the third phase of a decade-long effort that included Mercury, Gemini, robotic lunar probes, new boosters and supporting infrastructure, was the closest thing to today’s Vision for Exploration that has ever been accomplished.

Except for the rushed effort that led to Apollo 1, the overall enterprise was well designed and well managed. It was also — and this is important — a program that started with a goal but without a predefined path. Astronauts were testing procedures and equipment in space before the Lunar Orbit Rendezvous technique was chosen, before the Saturn 5 was designed and before there was any agreement on what the lunar lander would look like. Lessons from each step were used to take the next step in a logical progression.

The experience of co-authoring a recent book on the first satellites brought to light some interesting lessons from an era now seemingly remote. Take Project Vanguard, for example. America’s inaugural satellite effort was supposed to cost $20 million in 1954 dollars, but it ended up at $110 million.

The project is remembered as a flop because of the spectacular explosion of the first orbital attempt. However, its record for getting something into orbit was the same as the fondly remembered Jupiter C/Explorer system (three times in six tries.) And while the mushrooming cost of Vanguard brought the wrath of President Dwight D. Eisenhower himself, the program’s real success was unforeseen: it contributed advances in rocketry, guidance, tracking, etc., that still appear in the latest Evolved Expendable Launch Vehicles. The money for this “disaster” of a program was very well spent.

Risk was accepted in those early days. It was understood that space hardware was pushing the envelope and failures would happen. That acceptance of risk was, very properly, diminished when spacecraft began carrying humans. Human spaceflight must be made as safe as our technology allows, but, in our day, space programs of all kinds find themselves subject to a demand for zero risk. One thing history teaches very clearly is that progress with zero risk is a contradiction in terms.

The people who launched the Space Age, as well as the leaders who financed it, also understood that cost projections were uncertain. While the huge jump in Project Vanguard would cause consternation in any age, some degree of financial uncertainty was accepted as a given. The engine for the X-15, another success from this period, cost more than the original budget for the entire program. X-15 advocates stayed the course, with outstanding results.

Another lesson of those times was redundancy. Funding parallel developments was a common and successful way to keep risk to a reasonable level. A good example was Vanguard’s third stage. No one had built a solid-fuel stage of this size before, so two designs from different manufacturers were funded. (Both flew successfully.) This philosophy extended (although not with some debate about “wasteful” spending) into whole programs. The Thor missile was approved to back up the Jupiter, and the Titan ICBM was funded as a conservative backup to the more radical Atlas.

A lesson from Apollo is that the program worked because plans were constantly adjusted to reflect what astronauts learned about operating in space and what robotic probes reported from the Moon. In the 1970s and 1980s, with the space shuttle program, NASA learned a lesson we may call the Iron Law of Aerospace Costs. The Iron Law states that research and development (R&D) costs plus operating costs equals a constant. Scrimping on the former will lead to horrendous consequences in the latter, just as adequate funding for R&D can bring operating costs down.

Another lesson from a broad examination of completed and ongoing space programs is that schedule slips for technical or safety reasons must be considered acceptable, but slips for budgetary reasons always — always — result in higher total costs. A related lesson is that efforts to reduce long-term costs via broad R&D programs like the Space Launch Initiative are usually well worth it, even if government budgeters have a hard time understanding programs that don’t lead directly to a predefined operational system.

For the vision, NASA could do a lot worse than begin by resurrecting Space Launch Initiative . We can execute the vision with expendable chemical rockets only, but that won’t be the fastest or the most cost-effective way, any more than operating today’s airline schedule strictly with “tried and true” propeller-driven aircraft would be.

While NASA will need international and corporate partners to succeed in the v ision, NASA is the catalyst, the critical “single point failure” that cannot be allowed to fail. So the burden of implementing history’s lessons will fall heavily on NASA’s leaders.

Those leaders must perform the very difficult feat of making political leaders and the public share the excitement of this venture while making them understand that a clear, straight path to success in 2015 and beyond cannot be nailed down in 2005. Spending for technology development, redundancy and parallel development must be defended, while over-promising must be avoided.

The American public must be made to understand that the NASA budget is about 1 percent of the national budget, and that assuming problems we can’t fix with the 99 percent could be fixed with the 1 percent is completely illogical. Likewise, NASA and its allies must articulate and defend the point that, if we postpone exploration until we’ve solved every problem on Earth, we’ll never go.

NASA also must prepare for the possibility that 1 percent of the budget is too low, and a greater increase must be fought for. The examples of space programs cited above indicate that a significant, although not enormous, increase will be needed to cope with the known and unknown challenges ahead. Virgil might well have written, “Fortune favors the adequately funded.”

History tells us that even the most difficult challenges of exploration can be met. They cannot, though, be met by fooling ourselves. Making the nation understand the need for adequate funding, reasonable and flexible schedules, and, above all, the acceptance of uncertainty, is going to take a hard, continuous effort requiring all the resourcefulness and imagination of those inside and outside NASA who believe in the dream. It also will require that the first steps forward, like the development of the Crew Exploration Vehicle , must be successful to gain the consensus needed for the next step beyond.

All this, too, can be done. History shows how the American people can rise to great challenges and step boldly into new frontiers. We can build on this history to create a new future of exploration. Our generation will lay the groundwork. Our children will build observatories on the Moon. They will sift the red dust of Mars with their gloved hands. They will use robot probes, powerful instruments of observation and the human eye and brain to extend our quest for knowledge into the solar system and beyond. History, properly read, is only the beginning.

Matt Bille is a science writer and space historian in Colorado Springs, Colo. He is co-author with Erika Lishock of “The First Space Race” (2004), a history of the first Earth satellites.