Chapter 241: Perfect Success

Three hours before lunar approach.

The moon on the main screen in the Goheung Space Center control room had grown as large as a dish.

The Goldstone and Madrid bases of the DSN alternately tracked Selene’s signal.

The ‘Selene Kick Stage’ was entering the Moon’s gravitational field, following a curved trajectory and gradually descending toward the Moon.

“18 minutes and 40 seconds until LOI entry.”

Park Cheol-jin read out the timer.

“Target perilune 102.0 km, planned Δv 860 m/s.”

Then,

“Guidance residual rising.”

The Guidance, Navigation, and Control (GNC) system warned that the discrepancy between the planned path and the actual position was widening.

That wasn’t the only problem.

“Star tracker-2 saturated, star tracking lost.”

Too much reflected light had entered, causing a sudden drop in the navigation system’s accuracy.

Soon, warning lights began to flash in succession on the telemetry panel.

“IMU-B drift deviation spiking to 0.21 degrees/h.”

“Luna filter innovation value exceeds 3 sigma.”

“Expected perilune altitude fluctuating… from 102 to 38… 22… 17 km in a sharp decline.”

At 17 km, there was a risk of colliding with the Moon’s surface mountains or highlands.

The NASA Flight Dynamics Officer (FDO) swallowed hard and asked,

“This is off-nominal. Abort LOI-1?”

I immediately shook my head.

Nothing had been confirmed yet to warrant an abort.

“First, confirm the cause!”

Kim Se-bin and our team members quickly tapped on their keypads.

“The cause of the star tracker saturation is… solar reflection flare. The lens panel was hit directly by the Moon’s bright halo.”

“Keep-out angle 28 degrees. Beyond the operational limit angle range for the navigation sensor.”

Ivan Petrovich added further analysis.

“The IMU-B drift is due to thermal changes. The header tank pressure ripple and onboard clock time axis error overlapped. The internal clock deviation is estimated at +37 ms.”

Having identified the cause, I immediately gave Luna (Luna AI-RTOS) the command.

“Luna! Reset the navigation filter and reduce the star tracker weight to 0.2.”

First, we needed to confirm the precise location of the kick stage.

Next, it was necessary to reduce the reliability of the star tracker, which had been blinded by the flare.

I continued to issue commands.

“Blend DSN’s Doppler and distance data at 0.7. Reflect clock offset +37 ms, apply ‘flare rejection’ noise mask.”

Instead of relying on the star tracker, we reflected the Earth-tracked data with 70% reliability.

We also immediately corrected the internal clock deviation.

Finally, we applied a dedicated filter (noise mask) and algorithm (flare rejection) to eliminate sensor errors caused by solar reflection.

Luna responded immediately to my uninterrupted instructions.

[Application complete. EKF reconvergence in 14 seconds, settling thrusters firing.]

Micro-pulses ignited to press the propellant to the bottom of the tank.

A meticulous procedure that left no room for cavitation (bubbles in the fuel pump) to occur.

New data flowed from the DSN console.

[Delta-DOR received. Line of sight correction +6.2 microrad.]

I immediately recalculated the orbital vector.

The red band (predicted collision path) on the orbit panel gradually faded.

The perilune altitude also rose again from 17 → 31 → 64 → 91 km.

“Filter convergence complete.”

As I spoke, Kim Se-bin exclaimed,

“Perilune 97.3±0.9 km. Guidance status ‘green’!”

A collective sigh of relief filled the control room.

The NASA flight supervisor cautiously asked,

“Can LOI-1 be resumed…?”

I pointed to the countdown window.

The timer still showed ‘2 minutes and 40 seconds’ remaining.

[KTalk LIVE] — Real-time viewers: 32,187,655

└I thought my heart was going to drop just now;;;

└At least all the warning lights are gone now.

└Did you see Kang Tae-joon just now? His expression didn’t change at all, even in that situation?

└The awkward (?) voice that answered Kang Tae-joon’s question earlier… Could it be… Luna?

└Yeah, I was wondering the same thing.

└……

Fortunately, there was still a chance to enter LOI, so the subsequent process proceeded immediately.

“LOI-1 sequence load complete.”

“Main engine pre-valve open.”

“Header tank pressure 24.6 bar, stable.”

“Δv 860 m/s, target perilune 102 km maintained.”

As the team members spoke, I instructed the final check.

“Luna, maintain flare mask. DSN weight at 0.7.”

[Acknowledged. EKF convergence good.]

With Luna’s response, I shouted,

“Trans Lunar Capture LOI-1, ignite!”

With my signal, a long white-blue plume extended from Selene’s bell nozzle.

Vibration 0.04g, the combustion chamber pressure curve was as perfect as the one in the textbook.

Micro-thrust blending shaved off the slightest tremors around the main vector like a knife.

“Δv 300… 540… 810… Cut!”

As the engine shut down (SECO), the orbit/navigation parameters on the control screen simultaneously updated from ‘predicted’ to ‘confirmed’ values.

“Orbital energy, negative. Lunar gravity capture confirmed.”

“LOI-1 result, 97 x 7,420 km, inclination 88.7 degrees, RAAN 19.2 degrees.”

Just as cheers were about to erupt, I raised my hand.

“Not yet. Polar orbit circularization ends with LOI-2.”

As we entered the coast phase, Luna further reduced the star tracker exposure time

and widened the ‘keep-out’ angle boundary to 35 degrees.

As the thermal load on the tank’s outer wall became uniform,

the IMU-B drift flattened out again.

“Residual Δv margin 3.2%. LOI-2 will perform circularization + polar angle trim simultaneously.”

There was about a 3.2% margin left in the thrust needed to change the orbit,

and based on that, the orbit was stably changed from an ellipse to a circle.

“Target 100 × 100 km, inclination 90.0 degrees.”

As the Moon’s surface filled the screen, the countdown began,

and shouts were heard from all around.

“10 seconds until LOI-2!”

“Settling thrusters, maintain firing.”

“Main engine, ignite.”

This time, the vector tilted slightly to the side.

A profile that also performed plane changes.

It was a complex maneuver that involved both engine combustion and orbit inclination adjustments,

requiring very precise execution to reduce fuel consumption.

Luna scattered the trim pulses into dozens of pieces, like a symphony.

“Δv 52… 96… 142… Cut!”

The Selene Kick Stage’s main engine increased its speed by 142 m/s, then shut down.

Kim Se-bin shouted,

“Calculating results… 98.7 × 100.9 km, inclination 89.98 degrees, comprehensive error ±0.9 m/s.”

We had precisely entered a 100 x 100 km circular orbit passing over the Moon’s polar region, with an error margin far lower than the 1.1 m/s announced in the presentation.

The NASA FDO took the microphone.

“Guidance excellent. Lunar polar orbit—achieved.”

The FDO’s words set off an explosion in the control room.

Park Cheol-jin, suddenly relaxed, slumped into his chair but was still smiling.

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└Lunar capture and polar orbit circularization a huge success!

└Just need to deploy the payload now and we’re done!

└South Korea’s first ‘private lunar polar orbit demonstration’ ta-da!

└I have goosebumps right now.

└DJF stock up 39.6(+23.7%) to an all-time high

After confirming lunar orbit entry, I proceeded to the final stage.

“Fairing interior—Polar Orbiter status ‘green’. Link handshake pending.”

“Antenna blending test—polar relay link initiated.”

“Deep space navigation—horizon crossing solution up.”

“NASA payload, are you ready?”

Through the earpiece, the NASA flight supervisor calmly replied,

“Go. Godspeed.”

I shouted again,

“Polar Orbiter—separation in 3, 2, 1… Release!”

The faint sound of a spring mechanism reached through the speakers.

The separated orbiter quietly slid out, deploying its solar panels.

Then, Luna inserted a collision avoidance pulse to ensure a safe distance.

“Orbiter telemetry received. Deployment normal.”

“Polar antenna blending signal composite SNR +7.2 dB, quality ‘excellent’.”

“Deep space navigation deviation +2.4 m/s within baseline.”

A thin green line was drawn on the map panel.

The first real-time link coming back around the rim of the lunar south pole crater.

In the corner of the screen, a timer for ‘continuous 8-hour relay’ started ticking.

A procedure to confirm that communication could be maintained uninterrupted for over 8 hours.

I took the microphone one last time.

“This is Dojin Frontier Mission Control. Reporting. Polar Orbiter has settled into lunar polar circular orbit. Antenna blending demonstration ‘successful’, deep space navigation verification ‘passed’. Remaining procedures will proceed as planned.”

Hugs and applause echoed throughout the control room,

but everyone stayed at their stations until the final verification was complete.

Payload crossover test, thermal cycle verification, link failover… Check, check, check…

Finally, green lights appeared next to every item.

I quietly raised my fist and exclaimed,

“Polar Orbiter mission, complete!”

Whoooooooooooooooo!

Everyone in the control room jumped to their feet, cheering wildly.

This time, even I couldn’t hold back my emotions and joined in the celebration.

When we started this project, I never imagined we’d achieve such perfect success.

The results exceeded all expectations.

Beyond the glass, applause continued,

while on the screen, the Moon was serene, and the orbiter’s path traced precisely above it.