By Douglas Messier
Parabolic Arc Managing Editor
The Centaur upper stage, which has been propelling American satellites through space since 1965, is getting a major upgrade that would allow the venerable one-shot booster to perform in a series of new roles.
In the coming decades, upgraded Centaurs will make launching of spacecraft on Atlas V and Delta IV rockets much less expensive. They could also function as reusable space tugs, orbital fuel depots, and landing vehicles that would transport tons of cargo to and from the Moon, Mars and asteroids.
The full extent of the upgrades was laid out last week during presentations made by officials from United Launch Alliance, Masten Space Systems, and XCOR Aerospace at the Space Access 12 conference in Phoenix.
United Launch Alliance is upgrading Centaur’s systems on its own and in cooperation with XCOR Aerospace, with which it is developing a new engine to replace the aging RL-10 propulsion system. Masten Space Systems is working on outfitting the Centaur stage with the capability to land cargo on the Moon and other terrestrial bodies.
ULA’s Frank Zegler gave a detailed presentation on the efforts by a team he leads to overhaul the Centaur for the 21st century. The Centaur IVF (Integrated Vehicle Fluids) upper stage is designed to be cheaper to operate, more reliable, lighter, and more functional in space.
Zegler described a fundamental modernization of the vehicle, including eliminating toxic hypergolic fuels in favor of liquid hydrogen and liquid oxygen. The stage’s plumbing would be simplified, and many components and systems would be replaced by ones that are lighter and more efficient. The stage would also recapture waste heat and reuse it to improve energy efficiency.
The overall effect of the changes will be to simplify the Centaur and reduce its mass while making the stage more efficient, reliable and cheaper to build and operate, Zegler said. Currently, it is very expensive to integrate spacecraft with the stage. A particular problem comes from the large number of people involved in processing the Centaur.
Zegler said this approach difers fundamentally from past efforts to improve the efficiency of the upper stage. Previously, the company would spend an enormous amount of money building a less expensive titanium tank only to see those saving lost as the price of titanium increased.
A key element of the Centaur IVF is a new engine to replacing the aging and expensive RL-10. ULA is working with XCOR to develop a new propulsion system based on the technologies that the small Mojave company has developed for its Lynx space plane.
The XCOR engine is designed to be significantly cheaper to produce and operate. The other key feature is that the engine would be reusable hundreds or even thousands of times. This would make the Centaur IVF ideal for use as a space tug, orbital fuel depot, and landing vehicle for placing cargo on the Moon, Mars and asteroids.
NASA is interested in developing all of these technologies, which it sees as being key to future human exploration beyond Earth orbit. The space agency is especialy interested in orbital fuel depots.
Masten Space Systems’ Xeus project is focused on developing the capability of Centaur to land on other worlds. The Mojave company is using a non-flight ready Centaur donated by ULA to develop and test a system that could turn the upper stage into a cargo delivery system, Founder and CTO Dave Masten told Space Access 12 attendees.
Engineers are placing four, 3,000-lb. thrust Masten engines on the side of the Centaur and installing a guidance system so the vehicle can make a controlled landing. The plans call for taking the vehicle up to an altitude of 1 kilometer over the Mojave Desert and then bringing it down for a controlled landing on rough terrain.
A reusable Centaur lander could get five tons of cargo on and off the moon, Masten said. The work was inspired by a paper written by ULA engineers about six years that proposed a Centaur-based landing vehicle.
Masten said he would like to get NASA’s Office of the Chief Technologist to fund the project as a Discovery mission. The vehicle would be launched to the moon as a payload aboard the planned 2017 flight test of NASA’s new heavy-lift Space Launch System, he said.
However, such a flight would require that three different part of NASA agree to conduct the test. “It’s never going to happen,” Masten said with a laugh.