It seemed like the entire town of Woomera had braved the heat to come watch the launch from bleachers moved over from the school and laid out near the combination integration building and control center. At least a hundred and people had crowded together, watching the K-1 lift off from the pad a few kilometers away and fly away into the stratosphere, holding hands over their eyes or placing binoculars to their face to help follow it and fight the glare from the noon sun. The school had even made a field trip out, the primary and high schoolers mixing with the festival atmosphere common from any children blessed with a Monday excuse to be out of classes. Much of the town had taken an early lunch break and come out to watch the first rocket to fly from Woomera in half a lifetime. Not everyone was a local though--in truth, only fifty or sixty, just half the town population of 150. The rest were RpK personnel, ATK contractors, NASA observers, international press, and Australian service members and Thales Australia contractors from the nearby test range. There were even a handful of dedicated tourists, a combination which had brought the ELDO Hotel to near capacity for the first time in years. The launch events, broadcast from speakers mounted on the side of the building, had brought cheers and shouts, contributing to the festival atmosphere. This launch meant a lot to the town, particularly as the first of many--this would hopefully be no fizzle like Black Arrow and Europa.
Once the LAP had fallen over the horizon to the landing area, drifting gently under parachutes, and the RpK announcers called the nominal orbit of the OV, the crowd began to break up. The school children boarded their bus, and villagers and base staff began to pack up as well. Other broke out grills, getting ready for an impromptu party. The roar of diesel engines sprouted, as RpK technicians and ATK contractors warmed up the big straddle truck which would be used to retrieve the LAP. Already, a few utes were bouncing along the access road to the landing ellipse, carrying technicians to begin the safing process while the truck made its way more slowly. They carried one of the major improvements in K-1 operations since the vehicle had originally been designed in 1999: a GPS tracker located on the stage which had begun sending its location as soon as the stage registered touchdown. The landing ellipse covered a circular area nearly two kilometer in diameter, and RpK wanted to waste no time in finding the stage in the area. They hoped to have the stage safed, the parachutes cut away for repacking, and the stage brought back to the barn by the end of the day. If all went well, the OV would be back tomorrow, and it was better to have the LAP already safely secured before the OV touched down and put them behind.
For its part, the K-1 Orbital Vehicle had left the coast of Australia behind as it finished its OMS-1 burn. Now, five minutes later, it was already over the Marshall Islands, the last ground it would see below it until it passed over the French Frigate Shoals of the Hawaiian chain in another ten minutes. If the K-1’s avionics had been human, they might have taken a moment to reflect on the path that had finally brought it here. Almost a decade after the original Kistler Aerospace team had tried to bring their rocket to Woomera and after several false starts--the challenge by SpaceX to the Space Launch Initiative contract which had lead to the original Kistler’s bankruptcy, the acquisition by Rocketplane which had brought the ability to exit bankruptcy and bid on NASA’s COTS contract, and the critical investments by ATK which had helped paper over the cracks and reassure enough investors to secure funding for everything up to the flight today. It had been a massive bet, a series of tragically close calls, but the K-1 rocket had finally seen space. A human astronaut would have found it hard not to give thanks for their luck, for the view of the Earth spread below, or simply to take a moment to think about the crazy paths of life.
The rocket wasn’t human, though. It was only digital, a Motorola PowerPC architecture. Its radiation-hardened 200 MHz processors had little time free for such reflections on the nature of life. Moreover, it had a major challenge ahead of itself, and as Robert Frost might have said, orbits to go before it slept. The K-1 Orbital Vehicle was no simple upper stage, suited to just get to the right orbit, separate a payload, and safe itself. It was a true spacecraft, with attitude control thrusters, an ethanol/LOX Orbital Maneuvering System, and the recovery systems to bring it home--and it had a tightly controlled window for how long it could stay in space, where it needed to land, and how much propellant it had to get there. It wasn’t even a simple matter of flight optimization--the rocket also had to ensure it didn’t have an excess of OMS propellant aboard which could cause it to be too heavy as it descended into the atmosphere. The PowerPC chips went to work executing the Draper-designed, RpK-polished algorithms which would steer it through the series of five burns which would bring it to payload deployment and back home to the ground safely.
The first was already behind it, the cleanup burn with the OMS which had resolved any uncertainty in how the decades-old engines might perform in vacuum. The use of the OMS burn, a single-engine burn a minute after the AJ-26-60 engine had seen MECO, meant that the stage could essentially burn to depletion, leaving minimal residuals of the un-needed kerosene and main stage liquid oxygen aboard, while still tracking to a precisely calculated initial trajectory. The initial orbit shape was a strange one compared to most rockets--it had essentially set its apogee to the initial parking altitude of 500 kilometers, then nosed over and burnt purely prograde to add velocity until the perigee cleared Earth’s atmosphere. As soon as the bare essentials of orbit were satisfied, the main engine had done its work. The second burn would finish the job of circularizing at the target orbit.
The stage played a waiting game, biding its time and working ahead on the tightly calculated autonomous guidance problems until its first apogee over Minnesota. Under the watchful eye of radar dishes outside the company’s headquarters in Oklahoma City, the K-1 OV fired its OMS again, circularizing on target for the deployment of today's demonstration payloads, both simulated and real. It didn’t really need the watching--though the ground could watch via radar, its only communications for telemetry down and override commands up if needed came over NASA’s TDRS satellite network, bouncing down from geostationary orbit whether the satellite was in line of a ground station or not. It was insufficient for the video footage which the stage had initially beamed home, but it was enough for the stage’s four minders in the control center at Woomera and their backup team of six working under the eyes of the rest of the team at the ceremonial launch control at Oklahoma City. The orbiter fired just one engine on the burn, reserving the other for backup--the K-1’s conservative design meant it had redundancies everywhere the weight could be justified, and the OMS was critical to mission success and a safe return home.
The stage and ground confirmed the second burn’s results: perfectly on target. Another twenty minutes passed before the stage proceeded to payload deployment--more than an hour since launch. The hatch opened up and flipped clear of the payload bay, giving the camera recording onboard inside the payload module a view of space as a “boresight” from its mounting spot on the aft end of the payload module. The stage reoriented, pointing itself sideways along the orbital track to give some clearance between the payload and itself as they went along their way. The K-1 was carrying three payloads on this mission. Two were inert. One would remain attached--a chunk of gold alloy to be cast into ceremonial coins after the recovery of the mission, bound for those who had contributed to the launch. The second was also a fake payload, though it at least would be cast loose of the vessel. A steel frame and sheet metal structure contained a tank of nearly three tons of water, sitting on top of the payload dispenser. The forward telescoping portion of the Expanded Payload Module retracted aft and the elevator inside the payload module shifted forward, pushing the watery simulated payload to the rim of the bay. Under the camera’s watchful eye, the deployment system pushed the “satellite” free and away as the signal came from the avionics on redundant pathways. After another half orbit, once the K-1 OV had a chance to move clear, the simulator was just smart enough to use a nitrogen thruster system to orient itself retrograde, then vent the rest of its nitrogen through the water tank like an overgrown bottle rocket. The sublimating cloud would provide a visible signal to be tracked by Australians of the deployment system’s precision, and the venting “propellants” would both lower the simulator’s perigee and the remaining structure and tanks light enough to quickly deorbit.
The third and final payloads--and the only real satellites being deployed on the maiden launch--weren’t in the bay at all, but instead mounted among the avionics boxes, tanks, and thruster systems inside the aft flare. A PPOD dispenser, carrying three cubesats, was mounted just inside the view of the flare’s camera. After a few minutes were allowed for the mass simulator forward to drift away, the three satellites were kicked loose, the small boxes covered in foil and surface-mounted solar panels tumbling away above the Earth. One was a project by students at Oklahoma State University, lead by a masters student in engineering who was a former RpK summer intern, the chance for a launch donated by RpK to their home state in a gesture of goodwill. Similar goodwill drove the second of the three satellites in the standard 3U dispenser, this one built by students at the University of Adelaide. The third was from cadets with the US Air Force Academy and would do minor science experiments for the weeks before the tiny satellite fell into the atmosphere. If the simulator’s venting and the OV’s return to Earth went well, within a week or so these three spacecraft, totalling less than five kilos, would be the only record of the mission’s success on orbit. As the tumbling trio of cube floated away from the OV, grad students and cadets worked over their arrangements for contacting their tiny satellites trying to beat the odds of cubesats which saw many fail without every signalling home.
That was the end of the easy activities, the primary mission. The old military pilot joke was that the trip out was for Uncle Sam, and the trip home was for yourself. The RpK team joked that the burns until payload separation were for the customer, and then the burns afterward were for themselves. These were the three burns which left the avionics the largest optimization challenge. In atmosphere, the OV flew like a brick. Even worse than the Space Shuttle, the K-1 OV had a cross range of barely 100 kilometers. In order to ensure the safe return to the tiny landing ellipse, the stage would have to make its fifth burn, the retro burn, precisely in the right place. To get it to the right place with the right amount of propellant remaining, the stage had two burns in its arsenal--the phasing burns. By burning to raise or lower one side of its circular orbit, the stage could adjust to the second its orbital period, and thus its ground track over Woomera 22 hours away. The main burn would happen two hours after launch, the second would serve as a cleanup of the phasing just a few orbits before entry. The stage’s task was to determine the right amount to raise or lower the orbit to ensure it used up the right amount of propellant. The 32-bit, 1990s grade radiation-hardened Motorola chips thought long and hard, looked at the internal guidance solution, compared the position to the projections and to tracking, and judged the right solution. It lined itself up with bursts from the attitude jets and waited for its calculated moment. The OMS flared to life.
Monitoring the phasing burn was among the last activities that RpK’s team in Oklahoma City would take before handing off to their relief. Jean-Pierre Boisvert nursed a cup of lukewarm coffee as they waited for TDRS to update telemetry and bring the news if the stage was coming home or not. In the lead-up to the launch, he’d lead the simulation teams through ground override responses any number of failures, each more unlikely than the rest. In a nominal mission, the control teams at Woomera and Oklahoma City were so much window dressing for a vehicle that literally flew itself. In an off-nominal mission, they’d have to be ready to leap into action to come to the aid of a wounded, confused spacecraft to recover the mission, get the payload away, and bring home a corporate asset with a value measured in the tens of millions. He took a sip of the coffee and winced. Soon enough, they’d know if they needed to do any of that, or if the scenarios he’d brainstormed over reams of printouts with his engineers and over beers with his old RCAF buddy William Anderchuk when his company’s oil business brought him to town were just so much waste of time. The moment the OV had signalled it calculated for the burn came and went, and the telemetry flashed its updates. The controllers on two sides of the planet leaned forward in unison, fingers flying across keyboards to update their own projections and to query details of the spacecraft’s health. The team was disciplined and professional--Jean-Pierre was proud of that. They called off by the numbers as he polled down the list, no wasted time as the men and women he’d trained snapped back their answers. He’d learned to read them, though, and he knew the answers they’d give from the set of their shoulders as they leaned over their consoles.
“Power?”
“Go flight.”
“Propulsion?”
“Nominal! No residuals.”
“Guidance?”
“Go flight! Good burn, we’re right on target. Might not need OMS-4, phasing accuracy looks within acceptable limits. Updating ground retro estimate, OV analysis in progress.”
The team sat back, all smiles, the relaxation and confidence their shoulders had shown filling the room. The hardest part of the flying home was already behind them. Their baby had done its job, and was coming home. Now, they could go home themselves and rest, to wait for the landing tomorrow. The Woomera team would take over monitoring while they worked on finishing getting the LAP onto the truck and back to the barn, with a relief overnight, and then they’d pick back up as primary here in Oklahoma City in the morning. Jean-Pierre smiled behind his coffee mug. A hell of a thing, he thought to himself. A hell of a team.