MDV Leviathan B-IK

MDV Leviathan B-IK

Hydrolox Aerospike Kickstage Variant

Manufacturer: Sierra Dynamics
Type: Megastructure Deployment Vehicle
Configuration: B-IK (Block I with integrated Kickstage)
Propellant: Methalox (main stages) / Hydrolox (Kickstage)
Role: Extended-range Heavy Lift / Deep-Orbit Deployment
Operational Status: Commissioned / Operational

Overview

Following the success of the baseline B-I configuration, Sierra Dynamics advanced development toward an integrated kickstage variant to extend operational reach.
The B-IK trades a portion of its direct payload mass for significantly greater Δv capability and transfer versatility — the hydrolox kickstage is inserted into Low Droo Orbit by the main vehicle, from which it performs the final transfer and precision injection burns.

The Hydrolox Aerospike Kickstage maintains near-constant efficiency throughout altitude transitions, eliminating nozzle-related performance losses and granting exceptional control for orbital construction and deep-space deployment profiles.

Key Data

Configuration: B-IK (Integrated Kickstage)
Kickstage Mass (wet): 106 kt
Kickstage Engine: Hydrolox Aerospike
Kickstage Thrust: 101 MN
Kickstage Burn Duration: ~1.02 hours
Total Launch Mass: ≈ 4 527 kt
Total Liftoff Thrust: ≈ 57.3 GN
Recommended Payload to LDO (baseline): 300 – 350 kt (accounts for kickstage mass)

Recommended Kickstage Transfer Payloads

(With 30 % Safety Margin Applied)

These are conservative, mission-ready payload figures that the Serpentine Kickstage can Hohmann-transfer from Low Droo Orbit after main-vehicle delivery.
Values include a 30 % safety reduction from ideal maxima to compensate for steering, gravity losses, capture, and operational margins.

Vulco – Ideal Max: 131 kt / Recommended: ≈ 92 kt (≈ 92 000 t)
Sergeaa – Ideal Max: 364 kt / Recommended: ≈ 255 kt (≈ 255 000 t)
Cylero – Ideal Max: 576 kt / Recommended: ≈ 403 kt (≈ 403 000 t)
Tydos – Ideal Max: 207 kt / Recommended: ≈ 145 kt (≈ 145 000 t)
Urados – Ideal Max: 182 kt / Recommended: ≈ 127 kt (≈ 127 000 t)

Operation Guidelines

• Wait for the flight-computer prompt “Proceed to Launch” before liftoff.
• On lower-FPS systems, avoid time-warp during ascent to prevent control desynchronization.
• Mission is considered complete when “Ascent Completed” appears — the upper stage may then be discarded or used for further orbital work.
• The hydrolox kickstage is restart-capable for multiple burns within cryogenic limits.

Development Note

Integration of the hydrolox aerospike kickstage demanded extensive retuning of the Leviathan flight program.
Each configuration within the series requires independent validation before certification.

The B-IK emerged as the first production-ready extended-range variant — emphasizing precision, endurance, and controlled efficiency over brute payload mass.
Its operational maturity established it as the primary orbital-transfer workhorse of the Leviathan fleet, bridging the era of sea-launched heavy lifters with that of orbital megastructure deployment.

Credits

Developed and maintained by Sierra Dynamics
Technical Documentation by ChatGPT (GPT-5)
Poseidon’s Cradle Program Division — Operational Log Ref #SD-B-IK-O7