An unmanned mission, there was no cap on acceleration. The contents of the probe endured forces no human could survive. While NASA had tested the effects of extreme G-forces on protein cubes, they had not done so with a simultaneous lateral vibration. Had they been given more time, they would have.
The harmless shimmy, caused by a minor fuel mixture imbalance, rattled the payload. Mounted by strong bolts, Iris held firm. The protein cubes inside did not.
The thrust compressed the food while the shimmy rattled it. An effect similar to liquefaction during an earthquake transformed the protein cubes into a thick sludge. Stored in a compartment that originally had no left-over space, the now-compressed substance had room to slosh.
The shimmy also caused an imbalanced load, forcing the sludge toward the edge of its compartment. The shift in weight only aggravated the problem and the shimmy grew stronger.
“Shimmy's getting violent,” reported the Ascent Flight Director.
“How violent?” Mitch said.
“More than we like,” he said. “But the accelerometers caught it and calculated the new center of mass. The guidance computer is adjusting the engines' thrusts to counteract. We're still good.”
“Keep me posted,” Mitch said.
“13 seconds till staging.”
The unexpected weight shift had not spelled disaster. All systems were designed for worst-case scenarios; each did their job admirably. The ship continued toward orbit with only a minor course adjustment, implemented automatically by sophisticated software.
The first stage depleted its fuel, and the booster coasted for a fraction of a second as it jettisoned stage-clamps via explosive bolts. The now-empty stage fell away from the craft as the second-stage engines prepared to ignite.
The brutal forces had disappeared. The protein sludge floated free in the container. Given two seconds, it would have re-expanded and solidified. But it was given only a quarter-second.
As the second stage fired, the craft experienced a sudden jolt of immense force. No longer contending with the dead-weight of the first stage, the acceleration was profound. The 300kg of sludge slammed in to the back of its container. The point of impact was at the edge of Iris, nowhere near where the mass was expected to be.
Though Iris was held in place by five large bolts, the force was directed entirely to a single one. The bolt was designed to withstand immense forces; if necessary to carry the entire weight of the payload. But it was not designed to sustain a sudden impact from a loose 300kg mass.
The bolt sheared. The burden was then shifted to the remaining four bolts. The forceful impact having passed, their work was considerably easier than that of their fallen comrade.
Had the pad crew been given time to do normal inspections, they would have noticed the minor defect in one of the bolts. A defect that slightly weakened it, though would not cause failure on a normal mission. Still, they would have swapped it out with a perfect replacement.
The off-center load presented unequal force to the four remaining bolts, the defective one bearing the brunt of it. Soon, it failed as well. From there, the other three failed in rapid succession.
Iris slipped from its supports in the payload bulb, slamming in to the hull.
“Woah!” exclaimed the Ascent Flight Director. “Flight, we're getting a large precession!”
“What?” Mitch said as alerts beeped and lights flashed across all the consoles.
“Force on Iris is at 7 G's,” someone said.
“Intermittent signal loss,” came another voice.
“Ascent, What's happening here?” Mitch demanded.
“All hell broke loose. It's spinning on the long axis with a 17 degree precession.”
“At least 5 rps, and falling off course.”
“Can you get it to orbit?”
“I can't talk to it at all; signal failures left and right.”
“Comm!” Mitch shot to the Communications Director.
“Workin' on it, Flight,” came the response. “There's a problem with the onboard system.”
“Getting some major G's inside, Flight.”
“Ground telemetry shows it 200 meters low of target path.”
“We've lost readings on the probe, Flight.”
Mitch zeroed in on that last comment. “Entirely lost the probe?” Mitch asked.
“Affirm, Flight. Intermittent signal from the ship, but no probe.”
“Shit,” Mitch said. “It shook loose in the bay.”
“It's dradeling, Flight.”
“Can it limp to orbit?” Mitch said. “Even super-low EO? We might be able to-”
“Loss of signal, Flight.”
“LOS here, too.”
Other than the alarms, the room fell silent.
After a moment, Mitch said “Reestablish?”
“No luck,” said Comm.
“Ground?” Mitch asked.
“GC,” same the reply, “Vehicle had already left visual range.”
“SatCon?” Mitch asked.
“No satellite acquisition of signal.”
Mitch looked forward to the main screen. It was black now, with large white letters reading “LOS”.
“Flight,” came a voice over the radio, “US Destroyer Stockton reports debris falling from the sky. Source matches last known location of Iris.”
Mitch put his head in his hands. “Roger,” he said.
Then he uttered the words every Flight Director hopes never to say: “GC, Flight. Lock the doors.”
It was the signal to start post-failure procedures.
From the VIP observation room, Teddy watched the despondent Mission Control Center. He took a deep breath, then let it out. He looked forlornly at the blue folder, which contained the cheerful speech praising a perfect launch. Placing it in his briefcase, he then extracted the red folder with the other speech in it.
Venkat sat in his darkened office. He never decided to be in the dark. He'd just been lost in thought so long it got dark around him.
His mobile rang. His wife again. No doubt worried about him. He let it go to voice mail. He just couldn't face her. Or anyone.
A brief chime came from his computer. Glancing over, he saw an email from JPL. A relayed message from Pathfinder:
[16:03]WATNEY: How'd the launch go?
Dr. Shields says I need to write personal messages to each of the crew. She says it'll keep me tethered to humanity. I think it's bullshit. But hey, it's an order.
With you, I can be blunt:
If I die, I need you to check on my parents. They'll want to hear about our time on Mars first-hand. I'll need you to do that.