Opportunities for NASA to showcase its ability to pull off the extraordinary come few and far between these days as the agency grapples with declining budgets and a record of accomplishment that, ironically, has chased the exploration frontier to daunting new heights. The Aug. 6 landing of the car-sized Mars Science Laboratory rover was just such an opportunity, and NASA nailed it.

In what was appropriately billed as seven minutes of terror, the spacecraft carrying the Curiosity rover entered the martian atmosphere and executed a preprogrammed sequence of maneuvers culminating in the nuclear-powered robot being lowered to the red planet’s surface by a cable. Had anything gone wrong during those seven minutes — a mistimed heatshield release or botched parachute deployment, to cite just two of numerous possibilities — and the $2.5 billion mission would be lost. Given that it takes some 14 minutes for radio signals to make the one-way trip from Mars to Earth, all this had to be done without intervention from the ground — controllers had no way of even assessing the spacecraft’s status during the descent.

Most spectacular was the final phase of the deployment: Lowering the nearly 1-ton rover from the carrier spacecraft hovering 20 meters above the martian surface using the so-called Sky Crane. The novel plan looked incredibly risky, even farfetched, to many seasoned observers, but NASA mission managers said the Sky Crane approach, while admittedly very challenging, made the most sense of others that were considered including a direct landing aided by airbags or retrorockets.

There was more at risk than a lot of expensive U.S. taxpayer-funded hardware and a chance to explore the red planet in far greater detail than ever before. Failure not only would have damaged NASA’s reputation, which suffered greatly following the back-to-back losses of the smaller Mars Climate Orbiter and Mars Polar Lander missions in 1999; it likely would have quashed whatever remaining appetite U.S. law- and policy-makers have for backing the most challenging types of space exploration missions.

Like just about every other one-of-a-kind mission attempted by NASA or any other space agency, the Mars Science Laboratory mission cost more and launched later than planned. This is not only the nature of cutting-edge development projects; it’s also a reflection of political reality — NASA and its mission designers are well aware of sticker shock’s potential to kill projects in their planning phase and thus tend to be too optimistic in estimating costs and schedules. When the inevitable cost growth and delays on flagship-class missions come to light, hearings are held, budgets for other programs become threatened — the overruns must be covered somehow — and the specter of cancellation is raised. The James Webb Space Telescope, now scheduled for a 2018 launch, is a classic example.

For big missions that bust their budgets, the threat of cancellation must be real and palpable. Otherwise, managers and contractors would have little incentive to control costs. But imagine, for a moment, that the Mars Science Laboratory had been canceled. NASA would have been denied this history-making opportunity, while the public — and not just in the United States — would miss a chance to marvel at the achievement. Small missions can do a lot these days and their potential continues to grow, but there should always be a place for the highly challenging, wildly ambitious missions that bring out the very best in NASA’s engineering and scientific talent pool, both inside the agency and within its partner agencies and contractors.

Of course, flagship science missions are an increasingly endangered species these days not so much because overbudget projects are being canceled — although James Webb recently had a close call — but because NASA doesn’t have the political-budgetary support to start, or even participate in, new ones. Just last year, in a move that was both embarrassing and damaging to the United States’ credibility as an international partner, NASA was forced to withdraw from the European Space Agency’s Exomars program, which was to utilize the same Sky Crane landing system that proved its mettle in landing Curiosity. Today there are no missions in the planning stages that would take advantage of the technology trail blazed by the Mars Science Laboratory.

Curiosity now sits on the surface of Mars, sniffing its surroundings, taking pictures and preparing to embark on a two-year journey to answer questions about the red planet’s environment and current or past potential to support life. NASA deserves a moment or two to catch its breath and bask in the glory that it has achieved so far, even if Curiosity has yet to make its first move under its own power. The scientific community, Mars buffs and the intellectually curious public, meanwhile, can relish the anticipation of the scientific discoveries that lie ahead. Preserving the moment’s elation requires fixing one’s focus on a relatively short time horizon, however: NASA, having raised the bar in planetary exploration yet again, likely will have to wait at least a decade, perhaps two, for its next big opportunity.