By Eric Hand

When the Falcon 9 rocket makes its inaugural test flight, expected later this month, it will carry with it NASA's hopes for a new generation of low-cost rockets to ferry cargo and people into space.

The rocket--touted as a possible savior of human spaceflight--could also solve a serious problem facing the next generation of space probes. Satellites that observe Earth and nearby planets, as well as space telescopes able to look deep into the cosmos, are about to be hit by the retirement of the Delta II rocket, a workhorse that has launched 60 percent of NASA's science missions during the past decade.

Among NASA's stable of rockets, the Delta II is the right size for all but the most ambitious science missions, and at about $50 million per rocket the price was right too--ten years ago. But since then, the cost of a Delta II launch has roughly doubled, making it unaffordable. The last science launch scheduled for the Delta II is in 2011, for GRAIL (Gravity Recovery and Interior Laboratory), a mission to study the Moon's core by mapping tiny variations in its weak gravitational field.

"We're almost reaching the stage of desperation for launch vehicles," says Jack Burns, a space scientist at the University of Colorado at Boulder and a member of NASA's science advisory committee. NASA science chief Edward Weiler adds, "If there is no replacement ever for the Delta II, that would take away a critical capability." He hopes that in three or four years the Falcon 9, developed by SpaceX of Hawthorne, Calif., will emerge as a low-cost replacement. "Very much hoping, I might add."

SpaceX unveiled its plans for Falcon 9 in 2005, and a year later won NASA contracts worth $278 million to develop rockets that could carry supplies and science experiments to the International Space Station (ISS). In December 2008, SpaceX won a $1.6-billion contract for 12 ISS resupply flights, up until the end of 2015. The rocket's potential role expanded in February, when President Barack Obama proposed axing the suite of NASA rockets intended to replace the Space Shuttle and once again send humans to the Moon. Some $6 billion over 5 years--money that would have gone to the Constellation rockets--would instead be ploughed into commercial providers such as SpaceX, in the hope that they could transport not only cargo, but people as well.

This radical transition is still very much in doubt, as legislators in Congress fight to protect space-industry jobs. Yet even the most ardent critics of Obama's new space vision are eager to see whether Falcon 9 can help to keep NASA astronauts in space.

In the obsession over human space flight, many are overlooking the role that the Falcon 9 could have in replacing the Delta II, which came to prominence during a golden era in the 1990s when rockets were plentiful and relatively inexpensive. The rocket's biggest buyer, the U.S. Air Force, had to launch a constellation of global positioning satellites, and private satellite-communication companies such as Iridium were also snapping up the rockets by the handful.

But then the communications satellite market dried up, and the Air Force said it no longer had an essential need for the Delta II, conducting its final launch with one last year. Instead, the Air Force has committed to sustaining the very large Delta IV and Atlas V rockets in the Evolved Expendable Launch Vehicle program.

Price hikes

As buyers have bailed, the price of a Delta II, including launch, has shot up. A decade ago, they were a relative bargain, ranging from $50 million to $80 million apiece. Now, each one costs about $120 million--almost as expensive as the much bigger Atlas V--with further hikes expected. United Launch Alliance, the joint venture of Lockheed Martin and Boeing that makes the Delta II, would be happy to continue selling it to NASA. The components for five rockets are waiting to be assembled, says William Wrobel, who directs NASA's launch services program. The problem is that, without the additional buyers and bigger market, NASA cannot afford to pay for the upkeep of the launch-pad infrastructure that the Air Force had paid for. "NASA can't go it alone," says Wrobel.

Wrobel says that most imminent mission launches, such as the 2011 launch of the heavy Mars Science Laboratory and Juno, a mission to Jupiter, needed the extra thrust of an Atlas V anyway. But if NASA officials are forced to buy more Atlas Vs in the future, they will be paying extra for unused launch capacity. "The more that the launch vehicle costs, the less science mission you get for your money. Or fewer missions," says Alan Stern, a planetary scientist at Southwest Research Institute in Boulder, NASA's former science chief and an advocate of commercial space flight.

Several missions could take advantage of Falcon 9's leaner launch capability and lower price of about $50 million per launch. These include the Soil Moisture Active and Passive mission, an Earth-observing satellite due for launch in 2015; the International Lunar Network, a system of landers designed to measure the Moon's seismic activity, among other things; and modest-sized astrophysics and planetary-science missions that would launch in 2016.

All bets are not riding on the Falcon 9, however, which will launch from Cape Canaveral, Fla., and carry a prototype of its cargo capsule Dragon. Orbital Sciences, headquartered in Dulles, Va., and another winner of ISS cargo-transport money, is developing the Taurus II, another medium-sized launcher that is scheduled for first test flights in 2011 (see Mid-sized rockets need a boost). For the planned 2012 launch of the Lunar Atmosphere and Dust Environment Explorer (LADEE), Orbital is putting together stockpiled ballistic missiles into the Minotaur 5, which costs less than $50 million and is just the right size for the small Moon mission.

If Falcon 9's test launch is successful, it should be carrying cargo to the ISS within a few months. But scientists will have to wait a while longer--before a new rocket can carry a scientific payload, NASA requires three successful launches and a technical certification that takes about three years. NASA hopes to certify Falcon 9 or one of its competitors by the end of 2013.