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.