NASA Glenn dedicates display of historic Shuttle-Centaur booster

Michael Cole

A Shuttle-Centaur booster was officially placed on display at NASA’s Glenn Research Center in Ohio on Friday, May 6, 2016. Photo Credit: Michael Cole / SpaceFlight Insider

GLENN RESEARCH CENTER, Ohio — A historic piece of NASA space hardware officially came home on Friday, May 6, when NASA’s Glenn Research Center held a special ceremony to dedicate their newly completed Shuttle/Centaur G-Prime Upper Stage Rocket display. The 6,600 lbs (2,994 kg) Centaur G-Prime test article recently arrived at Glenn from the U.S. Space and Rocket Center in Huntsville, Alabama.

The booster had been on display outside the Huntsville Rocket Center for several years. The Center wanted to move it in order to make room for a planned redesign of their outdoor display, so the historic artifact was transferred to NASA Glenn, which had managed the Shuttle-Centaur program in the 1980s.

Glenn Director and former astronaut Janet Kavandi cut the ribbon to officially dedicate the display, along with former Director Lawrence Ross and others involved in the Centaur program’s history at Glenn, which at the time of the program was called the NASA Lewis Research Center.

Nearly forty retirees who had worked at Glenn on the Centaur program were also present for the dedication and ribbon cutting. Their pride in the project was evident as they posed for group pictures and closely examined the newly arrived booster, a product of their handiwork from some 30 years ago.

The various versions of the Centaur rocket have an impressive history of accomplishments over a fifty-year span. However, the particular version of Centaur that is now on display at NASA Glenn – the Shuttle/Centaur G-Prime Upper Stage – holds an interesting and controversial place in NASA history.

The then-named NASA Lewis Research Center developed the Centaur rocket in the 1960s, pioneering the use of liquid hydrogen as a fuel for spaceflight rocket engines. Although the super-cooled fuel was more dangerous and volatile than solid rocket propellants or kerosene, it was also more powerful, allowing it to propel heavier payloads greater distances. Flown as the upper stage for both Atlas and Titan launch vehicles, the Centaur upper stage rocket became an unqualified success and a NASA workhorse throughout the 1960s and 1970s. Notably, it sent Surveyor, Pioneer, Mariner, Viking, and Voyager spacecraft on historic missions to explore the Solar System.

However, the Centaur program’s future became clouded in the late 70s with the long-anticipated arrival of the Space Shuttle. In a NASA effort to reduce costs, the agency planned to shift a significant portion of spacecraft launch duties to the Shuttle and away from expendable launch vehicles like Centaur. This proposed shift to using the reusable Shuttle as a ferry to low-Earth orbit, and deploying spacecraft from its payload bay, sent the Centaur program at NASA Lewis into a dormant state. The program was charged only with fulfilling the few launches remaining on the schedule, which stretched a few years longer as the Shuttle’s readiness for flight continued to be delayed.

In his comments at Friday’s ceremony, former Lewis director Lawrence Ross, who was director of space flight systems at the time, reflected on that difficult period.

“We were all kind of worried about the future of the center,” Ross said. “Things were happening that we didn’t like. We began an effort to plan our own futures. In some ways, it was an effort to protect ourselves. But it ended up enriching our center in ways we had no way of anticipating. We wanted to get closer to the mainstream of NASA and do projects that were important to the nation. If we could do that, we knew our futures would be brighter.”

Their plans for a more mainstream future with NASA were an uphill struggle. The threatened loss of Centaur could not have come at a worse time, as NASA Lewis was already a potential target for elimination by Reagan-era budget cuts.

As NASA Lewis teetered on the brink, the plot thickened.

Numerous spacecraft that NASA intended to launch in its upcoming schedule required an orbit higher than the Shuttle could achieve. These spacecraft needed a booster to push them into their elevated orbits. The anticipated exploratory missions of Galileo to Jupiter and Ulysses to the Sun would require an even more powerful boost to send them on their way. The idea was to carry a booster-equipped spacecraft into space within the Shuttle’s payload bay, release it from the payload bay, then ignite the booster to send the spacecraft on its journey.

But which booster was best equipped for propelling a spacecraft on its mission after a ride aboard the Shuttle?

The process of choosing the booster set in motion a complex tangle of aerospace company lobbying, political intrigues, and inter-agency rivalries. The different cultures that existed within the competing NASA centers were put at odds in this highly charged climate, creating an uncomfortable and often unfriendly atmosphere about a project that would ultimately require a tremendous amount of inter-agency cooperation. Amid this thorny state of affairs, the choice for NASA was between two boosters. The first was a rocket called the Inertial Upper Stage (IUS), designed by the Air Force and managed by the Marshall Space Flight Center. The other was Centaur, designed and managed at Lewis along with the Air Force.

IUS was a solid-fueled booster and, therefore, safer to carry in the Shuttle’s payload bay than the hydrogen-fueled Centaur. However, the IUS was not as powerful as Centaur and could, therefore, be problematic for boosting the planned deep space exploration probes. It could also be lit only once, and would burn continuously until all its solid-propellant was exhausted, unlike Centaur – whose liquid-fueled engine could be stopped and started, providing far more control over the course of a mission. Those same liquid-fueled engines were the major objection of Centaur opponents, who argued against the notion of putting a complex and volatile hydrogen-fueled rocket in the payload bay of the Shuttle.

The long, successful, proven track record of Centaur caused NASA to lean in the direction of choosing Centaur. However, as rumors circulated about that possibility, the directors of Kennedy Space Center, Johnson Space Center, and Marshall Space Flight Center lobbied NASA Administrator Alan Lovelace to choose Marshall as the site for the Shuttle-Centaur program. They cited Lewis’ lack of experience with procuring hardware for manned spaceflight as their reason for recommending the moving of Centaur to Marshall.

“With Shuttle-Centaur, we ventured into the world of human spaceflight,” Ross said. “And the people who had inhabited that world before us didn’t want us there. We were not welcome.”

Ross expressed to Lovelace no offense at the three centers’ plan to wrest control of the Centaur program and move it to Marshall. Instead, he calmly argued to Lovelace that his Lewis engineers had an average of 13 years of experience with Centaur that would uniquely equip them to ready the adapted booster, on a very tight schedule, for its first flights aboard the Shuttle in 1986. The engineers at Marshall, Ross argued, would be starting from square one.

Ross won that argument. The Shuttle-Centaur program would be managed from Lewis, and a new era of funding and intense activity began at NASA Lewis. The Shuttle made its maiden voyage with John Young and Robert Crippen in 1981, and the Shuttle-Centaur program at Lewis started in the same year.

From there, things only got more interesting.

The engineers at Lewis had five years to ready a version of Centaur that could safely ride in the Shuttle’s payload bay. The cooperation this project necessitated between the Lewis and Johnson centers grew only in fits and starts.

“I think we earned some respect and became sort off grudgingly welcomed after a while,” Ross said. “But that made things difficult.”

In those same five years, the Space Shuttle launched itself into what seemed to be a golden age. American astronauts were going into space again. They were doing it routinely. The minor failures they encountered, they overcame. It was as if the Shuttle couldn’t really fail. This record of success, and the increasing pace of the program, precipitated a slow evolution in the managerial approach to risk and safety factors in the program. The program pushed its engineers and technicians to fly the fleet of shuttles with greater regularity and quicker turnarounds. Furthermore, concerning the Shuttle-Centaur, the 1986 launch windows for Galileo and Ulysses were rapidly approaching, pushing the Lewis engineers very hard.

“The schedule was unrelenting,” Ross said. “Planetary missions have a blessing and a curse. The curse is you can’t miss the date. The blessing is you’ve got to make the date.”

Amid the accelerated pace, resistance to Shuttle-Centaur and concerns about its safety continued.

“Safety was always paramount,” associate director of NASA Glenn’s Space Flight Systems Directorate, Scott Graham, told Spaceflight Insider. Graham was a young engineer in charge of cryogenic systems at the time. “We took that very seriously. We made lots of design changes in terms of redundancy. But it was always controversial, especially with the astronaut corps and the Johnson Space Center.”

Astronauts Rick Hauck and John Fabian had been vocal in their concerns about Centaur. A major concern among them was what would happen if the mission had to abort shortly after launch, forcing an emergency landing with a fully loaded Centaur in the payload bay.

“My responsibility was the fill, drain, and dump cryogenics system,” Graham said. “If there was ever going to be an abort of the orbiter during ascent and we would have to do an abort landing, it was actually too heavy for the orbiter to safely land with a fully tanked Centaur inside. So we had to design a dump system to rapidly dump both the hydrogen and oxygen out of the Centaur tanks prior to an emergency landing of the orbiter.”

Graham worked hand in hand with General Dynamics and other industry partners to develop that system. However, the idea of dumping hydrogen and oxygen from the orbiter as it glided through the atmosphere for an emergency landing never struck astronaut John Young as a good idea. He began to refer to the booster not as Centaur but as “Death Star”.

Hauck was slated to command the first Shuttle mission carrying Centaur, which would launch Ulysses to the Sun. Fabian was on the crew scheduled to carry the Centaur-boosted Galileo on its mission to Jupiter. The 1986 launch window for both missions dictated that the two flights would launch only five days apart – Hauck’s flight 61F on May 15 and Fabian’s flight 61G on May 20.

The rapid pace of the Shuttle program and growing concerns about the safety of Shuttle-Centaur precipitated Fabian’s retirement from NASA in September of 1985. He was replaced on the crew of 61G by Norm Thagard.

“We were flying what had been an expendable upper stage with hydrogen,” Graham said. “Putting a hydrogen stage inside the cargo bay was controversial. But we were all very confident that we had addressed all the safety issues.”

The controversy over Shuttle-Centaur would never be resolved. All questions about it became moot when the Space Shuttle Challenger exploded in the Florida skies shortly after liftoff on January 28, 1986. In the aftermath of the accident and its investigation, the Shuttle-Centaur program was canceled as part of the Shuttle program’s safety and risk-assessment overhaul.

“It wasn’t surprising after that,” Graham said, “that with the heightened safety culture within the agency that the program was canceled. It was kind of inevitable.”

The Challenger tragedy closed the book on the Shuttle-Centaur program. The Shuttle-Centaur can never be truly assessed for its merits or reliability because it was never allowed to prove itself. Nevertheless, the G-Prime configuration of Shuttle-Centaur was quickly adopted by the Air Force and served as the upper stage with their new Titan IV launch vehicle. This integration with Titan IV gave the Centaur G-Prime a new lease on life. Over the next 18 years, the Titan IV and Centaur G-Prime carried 16 classified national security payloads into orbit.

Its crowning achievement was launching the Cassini–Huygens spacecraft to Saturn on October 15, 1997. Cassini arrived at Saturn in 2004 and is still collecting data about the Saturnian system twelve years later.

Today, other versions of Centaur, coupled with other launch vehicles, continue to boost spacecraft into orbit, stretching its long career of spaceflight success to 56 years.

Officials at NASA Glenn are thrilled to have the Centaur, one of the proudest accomplishments in the center’s heritage, on display for the public. This year marks the 75th anniversary of the center, which began its existence during World War II as the Aircraft Engine Research Laboratory. The Shuttle-Centaur G-Prime Upper Stage Display was hurried to completion in time for the upcoming May 21–22 public open house event, the first open house event at NASA Glenn in seven years.