A time-lapse photo of a rocket launch powered by new aluminum-ice propellant. Credit: Purdue University

Last week researchers from Purdue and Penn State University launched a rocket that uses an unconventional propellant: aluminum-ice. The fuel mix, dubbed ALICE, is made of nano-aluminum powder and frozen water, and gets its thrust from the chemical reaction between the ingredients. The propellant is environmentally friendly, and it could perhaps allow spacecraft to refuel at locations like the moon, where water has been discovered.

Using aluminum for fuel is not completely new--the space shuttle's solid rocket boosters use a small amount of the metal, as will NASA's Ares rocket. But the new work involves making aluminum one of the key ingredients by using nanoscale particles. These tiny particles, when ignited, combust more rapidly than larger particles, forcing more exhaust gases out of the metal and giving the rocket the necessary kick.

The oxygen and hydrogen in water molecules enhance the combustion of the aluminum. Freezing the propellant keeps it intact, avoiding any premature reactions.

The propellant was able to lift a rocket 396 meters during an August flight test, which was funded by NASA and the Air Force Office of Scientific Research. Now, for even better performance, the researchers are working on adjusting the ratios of different ingredients and possibly mixing the nano-aluminum with larger aluminum particles.

A water-based propellant might one day mean that spacecraft could carry less fuel when traveling to distant locations like the moon or even mars. But it would also be nice to have a "greener" fuel for rocket launches back on Earth.

The launch of NASA's new rocket, Ares I-X, on October 28 was the first test flight of a new launch vehicle since the Apollo missions. The flight was spectacular and historic, but the famous Apollo 11 astronaut Buzz Aldrin says it was little more than a half-a-billion dollar political show.

In an editorial in The Huffington Post, Aldrin calls the rocket for "fake", because the Ares I-X was a prototype rocket built to look like the rocket designed to replace the aging space shuttles and take humans to the moon and beyond, Ares I. For example, its four-segment solid rocket boosters were taken from the space shuttle and the fifth segment was a mock, made of steel cylinders. The rocket's upper stage was also a mock-up (the final will include the J-2X engine and Orion crew capsule), but it used real parachutes for recovery of the boosters. The Ares I-X flight objectives were to gather data during the first two minutes of ascent, when the rocket is most likely to fail, to help engineers better design and development the Ares I.

Aldrin writes that technical problems have "haunted the Ares like leftovers from Halloween," and says that, "to stave off critics, three years ago the Project Constellation managers conceived of the 1-X flight to supposedly show some progress."

The concept of the Ares I-X flight, however, mirrors the development of the Saturn family of rockets that carried the astronauts, Aldrin included, to the moon. During the development of Saturn IB, for example, many test flights were conducted when different segments and parts of the rocket were engineered.

NASA's current plan is to use two rockets to return humans to the moon--Ares I for crew and Ares V as a heavy lifter, carrying things like a lunar habitat. Aldrin notes that it took just one rocket during the Apollo missions, and says that two rockets in development means "two price tags. Two ways for failure to occur. Or delays to develop."

Worse yet, neither rocket alone can accomplish a deep space mission. And deep space, such as Mars is, as our friends in the recent Augustine report stated, our destination in space . . . Ares 1 is too small, barely able to lift the crew space capsule. And Ares V is too weak to boost all of the elements together.

What do we need? One rocket for all our deep space missions. Save the taxpayer's money by canceling the Ares 1 and V. And go "back to the future" in designing the big beast.

Fortunately, Aldrin has a plan: use the commercial sector for transportation to the space station--which would save money--and start building a heavy lifter "worthy of Saturn V's successor." He says the moon should be an international affair, opening up the design competition outside of just NASA, and our efforts should be on Mars.

If we bypass a foolish Moon race . . . we will have time to refine the super booster to make sure it is compatible with our deep space goals, like missions flying by comets or asteroids -- or to the moons of Mars. Such a rocket would be ready when the time comes to colonize Mars. No more false starts and dead end rockets.

One thing the Augustine Panel's final report pointed out is that we should be building infrastructure in space, such as refueling technology, so that rockets that are smaller and cheaper could be used for missions that would otherwise be outside their weight class and larger rockets would have their capabilities enhanced.

The decision is still out on what the next U.S. rocket for space travel will be, but whatever it is (and Aldrin confesses he has his own design), he says, "heavy lifting doesn't have to be heavy spending, if we do the right job."

The future of U.S. human spaceflight is, without a doubt, in question. Today, the independent panel charged with reviewing NASA's future plans--the Constellation program, which includes the Ares rockets--will present its recommendations to the Obama administration. One option is to cancel the development of the Ares rockets. And now the head of the rocket program has resigned.

Steve Cook, program director of the Ares rockets at Marshall Space Flight Center in Huntsville, AL, is leaving NASA for a job at Dynetics, a defense contractor also based in Huntsville.

Despite Cook's assurance in an email to co-workers that the rocket is on track and work is going well, his departure is sure to raise eyebrows. Why would Cook want to leave NASA now? He was leading the development of what is intended to be the agency's next means of returning humans to the moon and Mars.

Yet the Ares program had to abort a significant motor test last week and recently pushed back--from August to October--the date of its test flight, Ares I-X. Furthermore, the Augustine panel has already stated publicly that NASA's current budget cannot support the rocket's development, or any development intended to send humans to the moon, for that matter.

NASA officials say Cook's departure will not delay or hinder the development of the rocket. Marshall veteran Teresa Vanhooser is taking over the Ares program.

In April, while reporting for my feature on Ares I-X, I spoke with Cook about the Ares program. Here's what he had to say about it.

Technology Review: What was the basis for your decision to choose the Ares rocket design to replace the shuttle?

Steve Cook: We made the decision four years ago, but we have been studying how to go back to the moon since we got there, and there are incalculable ways. After the Columbia tragedy in 2003, President Bush decided NASA needed a clear future. The space shuttle has been a great machine, a technological wonder, but it is time to move to a new mission. We now want to travel beyond Earth orbit, but we need [a vehicle] that is safe, reliable, and affordable, and we choose the Ares family. It will get us on to our intended destination.

TR: How does the Ares rocket design meet those needs--safety, reliability, and affordability?

SC: As a result of the shuttle accidents, we realized that we needed to separate the crew from the cargo. Also, the shuttle does not have [an abort system] for the crew to get away should a rocket failure occur, so we are building one for Ares. We also decided, for safety, the crew should be on top of the rocket away from the propulsion systems where most failures occur. We don't want foam to hit Orion [the new crew capsule] and damage it like Columbia.

Affordability was the second determining factor for choosing Ares. We want to build on 50 years of spaceflight experience, so we are taking the best from the past and combining it with modern technology to get this job done. We are building Ares I, which is a two-stage system where the crew rides on top so they can escape. Ares V, which will carry cargo, takes pieces from the Ares I, like the first stage. The first stage also looks more like [the] shuttle because it uses twin solid rocket boosters, and then the second stage of the Ares rockets has original lineage in Apollo. We are not starting from a clean sheet of paper, but there still is a lot of development work.

TR: How is the development process coming along?

SC: For the first time in four decades, we have three large-scale launch vehicles being built in parallel--the Ares I-X test flight, Ares I, and Ares V. We decided early on that we needed a development flight test, to test key characteristics of the rocket, but also the fundamental operations--how you stack it, how it flies, separates, and recovers. It is the first developmental launch vehicle since the '60s when we had Saturn.

For Apollo the goal was to beat the Russians to the moon and we did. Now we are standing [on Apollo's] shoulders and are building a reliable and safe system for long-term capability. But for Ares there is no big infusion of money to do this like there was for Apollo. Administration and Congress are deciding how [NASA's budget] should best be spent.