Back to the Moon-ARC

Chapter 2

The cause of the rendezvous and docking failure was still unknown, but virtually every member of the team that developed the system and its flight computer were called in to begin working on understanding the failure and figuring out how to fix it. Rocket scientists and engineers in Houston, Texas, and Huntsville, Alabama, found out that they wouldn’t be going home on time. A flurry of cell-phone calls, e-mails, and text messages to spouses or significant others went out explaining that they wouldn’t be home for dinner. Take-out pizza would be the most common meal of the day.

Thirty-six hours later, the command was given for Lunar Orbit Insertion. In typical NASA fashion, the media were told that all systems were “nominal,” thereby guaranteeing that the viewing public would be put to sleep by the whole event. To those engineers engaged in making it happen, however, “nominal” would not be the word that first came to mind. It certainly wouldn’t be the story they told their families and friends later in the week.

Upon receiving the command, the EDS fired up its single J-2X cryogenic engine, which began to burn two hundred twenty thousand pounds of hydrogen and oxygen, accelerating the hundred-ton Earth Departure Stage to greater than the twenty-thousand-miles-per-hour velocity required to escape the pull of Earth’s gravity.

If not for the incredibly cold liquid-hydrogen fuel circulating through the pipes wrapping the outside of the J-2X engine, the hellish six-thousand-degree heat produced by the burning of the hydrogen and oxygen in the combustion chamber would have almost immediately melted the nozzle. The fuel circulated through pumps and around the exterior of the rocket-engine nozzle and then back into the engine, where combustion would take place. The hydrogen and oxygen burned together and forced superheated and pressurized gasses out through the throat of the nozzle to its exit and then into space with a pure bright orange and white fiery glow.

The J-2 engine originally flew on the second stage of the venerable Saturn V rockets that carried the Apollo astronauts to the Moon. The J-2X was an upgraded version for the new generation of Moon rockets, and it was designed to complete its job in just less than seven minutes of burn time.

Throughout this acceleration, the Orion continued to perform what was known as the barbeque roll, so-called because it resembled the process of slow-cooking a pig on a spit over an open fire, slowly turning the pig so as to not overcook one side from the intense heat of the flame. The Orion performed this slow roll for the same reason—so as to not cook the ship by having one side of the vehicle continuously exposed to sunlight and therefore becoming a barbeque in space. After all, nobody likes their rocket overcooked on one side and raw on the other, especially not the astronauts inside it.

In addition, the delicate solar arrays that would power many of the onboard functions, previously unfurled like origami, were rotated so they would continuously point toward the sun. The solar panels were crucial in maintaining the electrical power required to keep the Orion’s systems functioning.

All of these pointing-and-control maneuvers were controlled by onboard computers. And all of the onboard computers that performed this function had within them a board manufactured by Alcoa Electric Corporation. This same board was used to control the automated rendezvous and docking maneuver between the Orion and the EDS.

“Bill, I think we’ve got one of the problems figured out.” Stetson, without having to look up from what he was doing, recognized the voice at the door as that of the chief engineer for the rendezvous and docking system. It had been almost two days since the nail-biting Earth-orbit rendezvous of the Orion with the Earth Departure Stage, and no one was really expecting the engineers to figure out the cause of the problem so quickly. Not that Bill Stetson would appear to be surprised by anything.

“Come in.” Stetson looked up from his desk and motioned for the seasoned but ever-eager Rick Carlton to take a seat at the small conference table across the room. Bill rose from his chair and strode to the table, the alpha male in the room by the way he carried himself and his purposeful stride to the chair adjacent to the one Carlton had just occupied. “What have you got?” he asked.

Carlton, no lightweight by anyone’s standards, was intimidated by the astronaut’s presence. Bill could tell, but then he hoped the man would get over it because Bill didn’t go through life trying to intimidate people. It wasn’t his style. He wasn’t trying to be intimidating—he just was. Asking him not to take control over just about any situation in which he found himself would be like asking the sun not to shine. Bill was just one of those people who demanded attention and he usually got it.

“Uh,” Carlton began his explanation, nervously shuffling the papers he’d brought in with him, “the glitch appears to be in the flight-computer software. You know the software was the tall pole leading up to this flight, and I am surprised the IV&V didn’t catch it long before now.” The NASA Independent Verification and Validation team had the task of approving all flight software. The team’s job was to be another set of eyes to review all the software, line by line, just to make sure it was correct and that there wouldn’t be any major flight-system failure from faulty computer code.

“Really?”

“Yeah. The computer is supposed to take all the sensor data from the Orion and route it to the systems that need the information to function. It’s supposed to take data from the laser ranging, the GPS, the sun sensors, and just about every other sensor on the vehicle and make sense of it. Sort it and then funnel it out to the elements that need it next. In our case, however, that didn’t happen.” Carlton paused, and Bill could tell that the pause was not only to take a breath, but also for effect.

“Why not?” asked Bill, looking at Carlton expectantly but not impatiently.

“Well,” Carlton began again, “the software got to the computer all right, but the code added the position-error function to the data twice, making its actual position appear to be incorrect, thus causing the ship’s thrusters to overcompensate in an attempt to get it where it was supposed to be—which it already was, at least the first time. Since it didn’t know where it really was, it appeared to be where it was at an earlier time. The thrusters fired to move it to where it was supposed to be, and then the lag happened again. The ship appeared to have not moved or moved only slightly. The thrusters then fired again, making the Orion move faster than it was supposed to in an effort to get to where it thought it should be when, in fact, it was already there.” He began to wonder if his wordy explanation was making any sense.

“Hmm.” Bill nodded.

“Are you following me?” Rick Carlton asked, but Bill Stetson was not just following him; he was ahead of him in his thought processes.

“So, the Orion, thinking it was sitting where it used to be sitting, fired its thrusters to get where it thought it was supposed to be when in fact it was already there. And then it got stuck in this loop, making the ship accelerate when it should have been slowing down. Correct?”

“Yes.” Carlton, who seemed pleased that Stetson had understood him, nodded and continued. “And then there is the matter of the missing GPS data. Shortly before Earth departure, the data started appearing again. The only thing we can figure is that there is some sort of short in the system. We’ve isolated the problem to a particular circuit board. A loose connector or a lead that wasn’t well potted could have caused it. We still don’t know exactly, but…” He trailed off, lost in thought or perhaps unsure of what he should say next.

“But what?” Bill asked.

“Well, the same board is used in several pieces of hardware throughout the Orion and some in the Altair.” Altair was the generic name of the lunar-lander craft, not the name given to any particular lunar lander. “We believe there is a quality problem with this one board, and that’s it. But there is a chance the problem isn’t isolated. If it’s a generic problem with the board’s design, well, then we have a big problem.”

Stetson knew what that problem would be. If the board’s design was at fault, and it had to be replaced wherever it was used in the entire system, then America’s return to the Moon would be on indefinite hold until a replacement was designed and the entire system assessed for any unforeseen changes that might result. It could mean a mission delay measured in years.

“Good work, Rick.” Trying to reassure himself as much as Carlton, Stetson added, “Let’s take it one step at a time. Since we can’t look at the board until the Orion returns from the Moon, let’s not sweat it too much. Once the team gets it in front of them on a workbench, they’ll be able to make that call.”

Carlton stood up, picked up his papers, and started to walk out the door. He almost made it before Stetson called out his name and asked another question.

“Rick, what other hardware might be affected?”

“Uh…” Carlton frowned and looked toward his feet before answering. “Lots. The Orion attitude-control system and solar-array pointing system, the Altair attitude-control system, both communications systems, and just about every other piece of hardware that has to be concerned with pointing in one direction or another. It’s all over the place.”

“Okay. Thanks,” Stetson responded. The tone of his voice conveyed both concern and that the discussion was over.

“I guess I’ve been dismissed,” Bill overheard the man mutter to himself as he hurried out the door and down the hallway toward his office. Bill paid it no mind at all. He had more important things to deal with.

Elsewhere, the now-docked Orion and Altair lunar-lander vehicles, thousands of miles away in space, separated from the EDS and began the remaining part of their journey toward the Moon.