How it works
Core elements
How the tunnel, gateway, GATES, power system and AstroLiner shuttle are arranged.
- Length. ~2050 km.
- Cross-section. Ellipsoidal (~17.5 × 12.5 m), optimized for the shuttle’s aerodynamic shape and stable magnetic levitation.
- Tunnel depth. Up to ~8 km. Greater depths are also possible if geological and temperature conditions permit. The permissible depth of the accelerator tunnel can be determined precisely only after detailed geological exploration: drilling boreholes along the route, establishing the temperature profile, assessing the stress state of the rock mass, fracturing and hydrogeology. The lower the temperatures and heat flow in the deep strata (approximately up to ~200–250 °C), the wider the range of technically feasible depths and the greater the freedom to optimize route geometry (curvature radii and transition sections), allowing peak g-loads and dynamic loads in the tunnel to be reduced while maintaining the target speeds.
- Construction. Combined. The initial section (~330 km) is a gently sloping underground straight that descends in a straight line toward the gateway to simplify acceleration. The main section is a buried or underground tunnel providing thermal stability, vacuum isolation and safety.
- The geometry of the track. S-shaped arc on the plot after ~330 km.
- The downward bow. Radius ~6300 km, smoothly leads the tunnel to the depth to create the required angle.
- Ascending arc. With a radius of 2500–3500 km, it brings the tunnel to the gateway at an angle of ~5–6° above the horizon. The radii are selected so that centripetal acceleration at hypersonic speed does not exceed 4g.
- The vacuum system. Each segment (~50 km) is autonomous, with its own vacuum pumps, sensors, and emergency valves.
Acceleration system
Acceleration and stabilization of the shuttle are provided by the interaction of its onboard superconducting magnets with distributed linear electromagnetic drives (windings) installed in the tunnel. These drives are segmented passive windings made of conventional conductors (copper, aluminum) and do not require cryogenic cooling.
- In the initial part of the tunnel (0-330 km). The drives are located mainly beneath the guideway, generating a magnetic field for levitation and initial acceleration at 4g, as well as for active compensation of gravity.
- In the middle part of the tunnel (330-2000 km), especially in the S-arc section. The drives surround the tunnel around its perimeter, providing precision acceleration, force-based centering of the shuttle in the middle of the tunnel at hypersonic speeds, and course stabilization in curves. In the final portion of the tunnel, where radial accelerations are high, structurally redundant and reinforced winding materials are used along the floor. Over the 330-2000 km section, acceleration decreases along a curve from 4g at the start of the section to 0g at its end, with the final speed reaching ~11 km/s by the end of the trajectory.
- In the final section (2000-2050 km). The final 50 km are intended for stabilization and centering before entry into the atmosphere through the atmospheric gateway. There is no acceleration on this section.
Pulsed energy from GATES substations is supplied to specific winding segments in strict synchronization with the shuttle position, creating a traveling magnetic field that interacts with the field of the onboard magnets to accelerate the shuttle. This architecture minimizes tunnel complexity, makes the tunnel maintainable, and places the high-technology elements on the reusable shuttle.
It eliminates the last mile problem.
Location and design
The gateway complex is located on the summit plateau of Mount Mohi (~3400 m) in the DR Congo. A broad southern plateau (16 km farther south) is reserved for future scaling and can accommodate dozens of parallel gateways. The structure is a massive facility with a main mechanical shutter and systems for creating a gas-dynamic barrier. In effect, it is a stationary ground-based jet engine with a triple annular nozzle aimed skyward at an angle, but its purpose is not to accelerate a body; it displaces the atmosphere and creates a buffer as the shuttle enters the atmosphere.
The gas dynamic barrier
The main working element. As the shuttle approaches, it initiates, several seconds in advance, the formation of a conical supersonic gas flow directed outward along the tunnel axis.
- Source and configuration. The gas-dynamic barrier is produced by three independent concentric annular jet engines (belts), or analogous hypersonic ramjet engines in a similar three-belt arrangement, installed around the gateway exit plane and operating on an air-hydrogen fuel mixture. Hydrogen is produced on site by electrolysis. This triple redundancy provides fault tolerance: operation of any two belts is sufficient to create an effective barrier, so the system remains functional if one of the three fails. Each belt has its own fuel-supply, control and ignition system. The belts are arranged around the outer part of the gateway, one behind another in stepped offset from the smallest belt to the largest; the mechanical gate is located inside the gateway behind the belt cascade. This allows the belts to be started without first opening the mechanical gate.
- Key functions.
1) Creation of outward-directed pressure to protect the tunnel vacuum during shuttle passage;
2) Preliminary displacement and heating of atmospheric air in the exit zone ahead of the gateway to create a gradient at the interface between the tunnel vacuum and the atmosphere, forming a gradient transition between the tunnel vacuum and the atmosphere.
The gas-dynamic barrier is not aerodynamic protection for the shuttle and does not shield it from the atmosphere. Its function is to extend the transition between the two media in time, converting the practically instantaneous (microsecond) shock load from contact with cold stationary air into a distributed millisecond load from contact with a heated co-directed flow. This does not reduce the integral aerodynamic forces, but it sharply reduces jerk and the high-frequency component of the loads, lowering the risk of local structural damage and thermal shock.
- Flow shape. A cone with an elliptical cross-section corresponding to the cross-sections of the tunnel and shuttle. It extends tens to hundreds of metres outward from three rows of annular nozzles in the jet belts of the atmospheric gateway.
The gas-dynamic barrier of the atmospheric gateway does not require a geometrically perfect, stationary or strictly axisymmetric cone. Its operating regime is inherently dynamic and permits temporal and spatial fluctuations in flow shape, density and velocity.
The critical and only strict condition for gateway operability is maintaining, throughout the shuttle's exit, a positive (outward-directed) gradient of pressure and momentum that completely prevents atmospheric air from entering the tunnel, together with preliminary gas-dynamic and thermal preparation of the atmosphere in the exit zone. This substantially increases the reliability and practical feasibility of the system.
Thus, the flow shape is treated as an adaptive parameter rather than a target value and is optimized in real time using integral characteristics (pressure, mass flow rate and momentum), rather than a rigidly prescribed geometry.
- Scalability and testing. Unlike the thousand-kilometre accelerator, the gateway structure is modular and readily scalable. The key technologies — creation of a stable supersonic gas-dynamic cone, synchronization and operation of the jet belts — can be fully developed on full-function physical test stands at scales of 1:5 or 1:10, allowing the project's main technical risks to be retired before full-scale construction of the main route begins.
The security system
Working with hydrogen imposes heightened explosion and fire safety requirements. The entire gateway infrastructure is designed accordingly: redundant hydrogen-leak detection systems, inert nitrogen purging of pipelines, explosion-proof equipment, physical separation of electrolysis units, storage facilities and engine belts, and directed ventilation ducts for safely venting possible releases into the atmosphere away from service personnel and critical infrastructure.
Dimensions and launch mass
Length ~150 m, elliptical cross-section ~10x15 m. The shape is a hypersonic wedge optimized to minimize drag and thermal loads while penetrating the atmosphere.
- Optimal launch mass. ~15 000 tonnes.
The shuttle mass of 15 000 tonnes is the result of seeking an engineering-economic optimum lying in the “golden mean” between physical constraints and implementation feasibility.
| Criterion | The lower boundary (< 8 000 – 10 000 t) | Optimum (15 000 t) | The upper limit (> 20 000 – 25 000 t) |
|---|---|---|---|
| Aerodynamics and overloading | The resistance force Fd = ρ·A·v2 creates high overloads a = Fd/m, requiring complex active stabilization and leading to peak heat loads. | Inertia dominates. Atmospheric drag causes initial short-duration (up to 5 sec) loads of ~3–6g, allowing the use of simpler shock-absorption systems and thermal protection. | Overloads are reduced slightly, but the benefits are levelled by other factors. |
| Heat mode | Low heat capacity. Low m mass leads to rapid temperature rise ΔT = Q·t / (m·c), requiring extreme systems of active cooling. | High thermal inertia: a massive design absorbs and dissipates the peak heat of short-term atmospheric penetration, allowing a combination of passive and active heat protection. | The heat capacity is increasing, but the heat from the massive structure becomes a separate problem. |
| The power of the launch | The required energy E = ½·m·v² is acceptable, but does not compensate for the disadvantages. | The clever balance. The displacement energy up to 11 km/s is ~9×10¹⁴ J (~252 GWt·h), which corresponds to the capabilities of the distributed system of GATES and accumulators. | Energy costs are rising linearly, requiring disproportionate increases in storage capacity and capacity, which is not economically viable. |
| Construction and logistics | It's feasible, but it doesn't give the key advantage of an inertial tarn. | The dimensions and mass are compatible with modern shipbuilding docks, welding and transportation methods. | The design is losing its rigidity, there are problems with its own fluctuations, assembly, delivery to the start point, and the cost is rising super-linearly. |
| The philosophy of StarRoad | It's a relatively lightweight device, vulnerable to the atmosphere. | It realizes the paradigm of the inertional tarann: the atmosphere is not a barrier, but a short-term outrage that can be overcome at the expense of mass and strength. | It's becoming an industry-wide challenge, making it impossible to save on scale. |
- Physically is above the threshold (~10 000 t), after which inertia begins to dominate over aerodynamic impact.
- Energy does not lead to an exponential increase in infrastructure requirements.
- Technically remains within the scope of scale-up industrial practices (shipbuilding, heavy machining).
- Economically balances between lowering the cost of the withdrawal by scale and limiting capital expenditure.
Thus, this parameter is the computational optimum that makes StarRoad's concept physically viable and economically justified.
Compounding and systems
The entire interior architecture is designed as a multi-level longitudinal structure with a functional division along the height of the building.
- The bottom and the back of the body fully allocated to energy and power systems: on-board reactor, heat exchangers, active cooling circuits, power converters, energy storage, The heat carrier's main lines and the elements of the marine power plant. This position reduces the center of mass of the shuttle, increasing the stability of the hypersonic flight, planning and conduction, and simplifying the heat and radiation protection of the upper sections.
- Superconducting system of levity and stabilization It's integrated along the hulls of the shuttle and partly in the bottom. The superconducting modules are fixed directly behind the outer shell and heat shielding layer, which minimizes the gap between the magnetic field and the passive shell of the tunnel.
- along the board along the entire length of the hull, including the upper and middle zones to the line of the displacement barrel;
- the middle and back of the bottom;
- except for the exit zones of the main wings and mechanical niches.
This distribution ensures an even magnetic field, high resistance at hypersonic speeds and failure resistance at local damage.
- Middle part of the body The main wings are removed from the interior of the body and isolated from the energy and cargo sections. The front of the middle zone of the nose is used to place small forward control wings used for trajectory correction and stabilization in transition modes.
- The upper part of the body It's designed to accommodate a universal shift module of payload. The module is standardized by size, attachment points, mass and permissible centre of gravity position and can be configured as cargo, tanker, passenger or combined. The module is installed and removed in the dock before launch, and can also be removed in orbit after the upper barrel is opened. The cargo compartment is equipped with a built-in hydraulic or electromechanical lift and guides that allow the automated lifting and removal of the modules in microgravity conditions without the participation of the crew.
- The upper slits They are not a carrier element of the power frame and perform the functions of aerodynamic bypass and orbital access. Once the barrel is fully opened and fixed, the panels are automatically rolled up, and then a refrigerant is applied to the barrel to release excess heat into the vacuum.
- The nose of the shuttle has a multi-level functional composition:
- the upper nasal zone bridge, control, navigation and communication systems;
- the middle nasal zone of the mechanisms of small forward wings and control surfaces;
- the lower nasal zone of cryogenic fuel tanks and refrigerant, providing minimal hydraulic resistance and maximum rapid cooling access to the nasal cooling systems during atmospheric penetration.
This combination provides short heat and hydraulic circuits, reduces the heat inertia of the nose and increases the reliability of heat protection systems in the most congested part of the flight. The overall design of the shuttle is a rigidly structured, scalable and modular architecture, optimized for hypersonic start, orbital operations, Autonomous navigation and multiple operation without deep overloading of the hull.
The thermal protection of the body
The hull's nose and bottom are equipped with a multilayered composite-metal thermal protection system, designed for extreme heat and dynamic loads during hypersonic flight and subsequent powering. The structure combines passive and active elements and includes:
- an external heat-resistant layer resistant to short-term temperatures of thousands of degrees and intense radiation heating;
- a metallic substrate with a force that perceives mechanical and vibrational loads;
- active cooling contours that ensure the removal of heat from the most stressed areas, primarily the nasal part and the front edge of the bottom;
- replaceable ablation elements in local critical zones designed for controlled wear without damaging the main structure.
The thermal protection system is designed with the heat shock of the heated body in contact with water when landing in the ocean, including sharp temperature gradients and cyclical heat stresses. The architecture provides for segmentation and modular replacement of the most loaded elements during regulated service, which increases repair capacity and resource of multiple use.
Wings
The belt is equipped with two pairs of protruding wings, designed for stabilization, planning and landing.
- The front pair of wings provides trajectory correction, pitch and roll stabilization, and damping of dynamic disturbances. They deploy after the vehicle enters the rarefied layers of the atmosphere for gliding.
Parameters of each front wing:
- length (range from root): ~35 m;
- width by root / finishing: ~14 / 7 m;
- The area: ~360–400 m2.
- The back wing pair . is the main aerodynamic surface of the shuttle.
Parameters of each back wing:
- length (range from root): ~100 m;
- width by root / finishing: ~14 / 7 m;
- The area: ~1000–1100 m2.
The total wing area is about 2800–2900 m2. Additional contribution to the lifting force is the carrier form of the fuselage, which increases the effective aerodynamic area by about 20–30%.
In the subsonic mode, the sum configuration provides the orientational aerodynamic quality of L/D ≈ 9–13, which allows for stable planning and controlled selection of landing point. Typical planning and drainage speeds are estimated in the range 90–120 m/s (≈ 320–430 km/h). At such speeds, the safety of landing is determined not by the absolute horizontal speed, but by the vertical touch speed, angle of attack and glyssad profile.
Parachute systems
To reduce the impact loads when driving and expand the permitted landing window, the shuttle is equipped with a multiple parachute-parafoil system, which works as a conditional-state contour of soft landing.
- Architecture and location. The system includes two parafile positions:
- one in the upper aft section;
- One in the upper front part (just past the nose area).
Each position is executed according to the scheme . N+1 (basic + reserve parafoil) with independent layers and elongated lines. cross-sectional line of attachment to the power frame, which reduces local peak loads and increases tank and crane stability. The space of the domes is spread along a longitudinal axis, excluding mutual influence and splashing.
- Places and working mode. The parafoils are not designed to fully hold the weight of the apparatus, but to dampen the vertical speed at the end of the track and form the phase of smooth touch.
- area of one main parafoil: ~4500–6000 m²;
- total active area with both parafoils operating: ~9000–12 000 m².
The target value of the vertical speed at the touch point Vz≈1 m/s.
- Criteria for inclusion. The parachute-parafoil system is used Only if necessary. The landing algorithm takes into account total overload (vector sum of aerodynamic, inertial and hydrodynamic components):
- if the estimated total overload at touch not exceed 4g, landing is performed without use The parafollow (on the wings);
- when The risk The overhead 4g The system activates and reduces the vertical component speed to the target value, translating landing into a smooth slipping mode.
- Recurring. Paraprofils, barbed systems and attachment nodes are designed for multiple use with regulated service (inspection, drying, replacement of rapidly moving elements) without disassembling the body's power frame.
Autonomous power and motor installation
The vest is equipped with a fully autonomous energy-driven system designed for the entire mission cycle: from manoeuvring in orbit to months of autonomous swimming.
- The basic The source The energy of the onboard nuclear reactor.
- Type of the car: A compact fast salt dissolving reactor (SMR) or a high-temperature gas-cooled reactor (HTR) of the next generation. In the future a compact thermonuclear module (for example, based on a field-compression scheme, like Helion Energy).
- Power: electrical 10-20 MW, thermal 50-100 MW.
- The destination: energy supply of all on-board systems, superconducting elements of the magnetolevitation system, electrical and electronic plasma engines (EMPD), active cooling systems and drivers for autonomous swimming. The reactor is designed to operate without re-starting the fuel during the entire life of the shuttle (5-10 years).
- The onboard superconducting levitation and stabilization system. Along the hull of the shuttle are cryogenic modules with superconducting magnets based on high-temperature superconductors (HTCs) cooled by liquid nitrogen or hydrogen from the board systems. These magnets create a powerful main magnetic field for levitation and active stabilization (a system of magnetic pendulum). They allow the shuttle to maintain levitation even when the external power supply of the tunnel is completely turned off due to induction interaction with passive wrap-rails (magnetic mirror effect).
The system of stabilization management is built on the hierarchical principle:
- Passive contour (microsekund): the induction connection of superconductors with the tunnel wrap creates a returning force automatically at any shift without the involvement of electronics.
- Hardware contours (microsekund millisecond): specialized schemes (FPGA, ASIC) detect imbalances and switch sections by hard algorithms.
- The programming contour (milliseconds tens of milliseconds): The onboard calculator (with limited AI support) redistributes the currents between the superconducting sections to compensate for slow drift and local imbalances, without requiring a reaction in the nanosecond range.
This architecture provides milliseconds of response time to the shock, which is well above the stability requirements for a 15 000 tonne-tone shuttle at hypersonic speeds.
- The main ones The engine: high-pressure electromagnetic plasma engines (EMPDs).
- The principle is: magnetoplasmodynamic (MPD) engines or azimuth-flowing (VASIMR) engines powered by a on-board reactor.
- Thrust: up to 50–100 kN (5–10 tonnes-force) in pulsed mode, sufficient for orbital corrections, deorbiting, and transfers between orbits.
- The working body: liquid xenon, argon or hydrogen (also used for cooling systems).
- The autonomy: The engines are controlled by an AI on board, capable of calculating and performing manoeuvres for orbital station connections, unloading and return.
- Heat system The management:
- The moving radiators. Liquid-containing panels deployed in space to release excess heat from the reactor and equipment into the vacuum.
- Phase heat accumulators (TA). Critical elements are located in the nasal part and critical nodes. They absorb peak heat (megajouli) when the atmosphere is penetrated at start and inlet, preventing overheating of the structure. In space or ocean, heat is slowly released through radiators or into the environment.
- The system of active cooling. A closed-loop liquid helium/hydrogen for emergency cooling of the heat shield and critical elements in flight.
- Reserving and safety: Duplicate reactor control systems, independent cooling circuits, emergency heat dissipation devices.
Autonomous landing and marine systems
After being flooded in a given area of the Atlantic, the shuttle is converted to a fully autonomous marine shuttle.
- Propulsion system. Two retractable azimuth thruster units or waterjet propulsors provide high maneuverability at low speeds.
- Energy for swimming. Electricity for drivers and onboard systems the standard onboard nuclear/thermonuclear reactorThe reserve of the active zone is enough for many months of autonomous transitions.
- Navigation and communication. Satellite (GPS/GLONASS), inertial navigation, radar and navigation leaders for surface-recognition.
- The final braking system. For extinguishing the remaining speed (100-150 km/h) before touching the water, the combined system is used: small area brake parachute (for stabilization and initial braking) and short pulse of marching plasma engines (for precise shutting down of vertical speed). The parachute fires after the flood.
This configuration allows the shuttle to travel to the landing port or to the towing point without immediate assistance. It can autonomously hold on to a storm surge, make long transitions and arrive at a designated dock for scheduled service, turning from a spacecraft into a robotic sea shuttle.
AstroLiner-S: Started / Simplified
During the early stages of StarRoad implementation, and as a baseline, technologically simplified and operationally more conservative configuration, the initial shuttle version — AstroLiner-S (Simplified / Start) — is envisaged.
This modification is a fully functional, yet energetically and systemically simplified version of AstroLiner, designed for initial operation of the main line, early cargo and manned launches, and to reduce the technological, operational and regulatory risks of the system.
- Key idea of AstroLiner-S. AstroLiner-S implements StarRoad's core paradigm — inertial penetration of the atmosphere, but without an onboard nuclear or thermonuclear energy source and with the launch mass and dimensions of the main version fully preserved.
All the energy-extreme operations (disconnection, levitation, stabilization in the tunnel) are fully carried out in the ground infrastructure.
The AstroLiner-S belt is:
- by an autonomous transport apparatus,
- fully reusable,
- capable of self-orbiting, descending and returning,
- but using only chemical pull outside the tunnel,
- Not containing on board sources of high-power ionizing radiation.
- Energy and superconducting systems. In the configuration of AstroLiner-S , the following are completely excluded:
- nuclear and thermonuclear power plants,
- radiation, heat and accident risks associated with them,
- The scenes of irreversible tunnel and gateway pollution.
Superconducting elements of levitation, stabilization and interaction with the trail:
- pre-charged before start,
- are transferred to a permanent mode,
- They're isolated from each other and controlled by a flight system.
The power supply of the on-board electronics, control and protection systems is provided by accumulators and inertial accumulators (machines), which are designed for a full cycle of tunnel disassembly with time reserve.
Active control of the superconducting contours in the displacement process is limited to small adjusting currents and emergency modes, which eliminates the need for a high-powered continuous power source on board.
In orbit, folding solar panels are used as an active energy source.
- Motor installation outside the tunnel
All AstroLiner-S orbital operations are performed using chemical pull.
The belt is equipped with:
- medium-traction chemical marching engines (LOX/LH₂ or LOX/LCH₄ class),
- the duplicate guidance and emergency management (RCS) systems .
The motor installation ensures:
- the launching of the aircraft into target orbit after leaving the atmosphere,
- correction of the orbital parameters,
- deorbiting,
- controlled entrance and return.
The rejection of the electrical and magnetic plasma engines in this version is due to the absence of a high-powered power source on board and is not considered an architectural limitation of the system as a whole.
- Return and repeated
The AstroLiner-S is capable of:
- autonomous disembarkation from orbit,
- a shallow, controlled atmospheric entry,
- aerodynamic planning,
- landing in the ocean using wings and a parachute-parafoil system.
The absence of a reactor makes it much easier:
- maritime exploitation,
- the regulation of services,
- Rehabilitation of the machine after extra-ordinary landings.
- The Role AstroLiner-S I 'm not the development of StarRoad
AstroLiner-S is considered as:
- the first production version of the StarRoad shuttle,
- a platform for accumulating launch and failure statistics,
- means of early commissioning of the system,
- basic transport for the initial orbital infrastructure.
As the project progresses, compact high-power power sources emerge and experience builds, the AstroLiner-S can be evolved to complement or replace the full-featured version of AstroLiner, It's equipped with high-powered power plants and electromagnetic plasma engines.
Thus, AstroLiner-S is not a compromise but a logical entry-level configuration of the system, enabling StarRoad operations to begin earlier, more safely, and with lower systemic risk without changing the fundamental architecture of the main line.
The purpose and principle
The project includes the creation of its own integrated energy and climate infrastructure of gigawatts class based on the modified technology Enhanced Geothermal Systems (EGS). As a working body, supercritical carbon dioxide (sCO₂) is used, obtained by direct capture from the atmosphere (Direct Air Capture, DAC). The system combines three critical functions: 1) active management of the geothermal heat field to ensure the thermal stability of the accelerating tunnel; 2) generating basic electricity; 3) long-term utilization of atmospheric CO₂.
The underground architecture of the GATES
To ensure thermal stability, energy independence and durability, each accelerator tunnel is accompanied by a complex of seven small-diameter service tunnels. constituting the integrated system of the GATES:
- Six main collector-and-energy tunnels (diameter 2 m). They are located 30 m below the accelerator-tunnel floor, with a uniform 7 m spacing between their axes. They operate in pairs with reversible circulation of aggressively subcooled (+5°C) supercritical CO₂. This arrangement forms a continuous cooled slab more than >15 m thick beneath the full accelerator cross-section, eliminating thermal bridges.
- One technical service tunnel (diameter 3 m). It is located at the same level as the accelerator tunnel, 3 m to the side. It provides continuous diagnostic and repair access without stopping traffic. The GATES tunnels are designed for the combined effects of high internal pressure (up to 25 MPa), rock pressure, and dynamic loads. The entire seven-tunnel complex is excavated by a fully robotic fleet of micro-tunnel-boring machines (micro-TBMs). GATES physically and functionally separates the energy infrastructure from the transport infrastructure, providing exceptional reliability and maintainability.
Cooling system and TCMC
- It's a deep cooling outline. Under the accelerator tunnel are collector-energy tunnels of the GATES, through which the working body circulates on the basis of CO₂ in a dense high-pressure or supercritical mode. The target temperature range of the cold stream before entering the collectors is about +5...+15°C in the standard low temperature mode. After selecting geothermal heat and passing the depth site CO₂ it can heat up above +100°C depending on the depth, heat flow of the strains and the energy generation mode. The contour diverts geothermal heat, forms a cooling zone under the main tunnel and allows the highway to be laid safely at depths of about 5–8 km.
- Hydro-Thermal Main Canal (HTMC). Along the StarRoad route, parallel to the service highway, power transmission line, and communications, the Hydro-Thermal Main Canal — HTMC — is constructed. It links the terminals into a unified surface heat-rejection system.
The GTMK is a water channel about 5–8 m wide and 2–3 m deep. Several independent high-pressure pipelines-smeeviki pass through the bottom of the channel, through which CO₂ is moved between neighboring terminals. Water serves as a heat buffer and intermediate heat carrier.
After turbine, heat exchange or compressor nodes CO₂ enters the serpentine motor with a temperature of approximately +50...+80°C. On the long terminal section of about 50 km, it gives warm water, cooling to about +22...+35°C depending on the season, air humidity, rainfall intensity, radiation cooling and the operating mode of the channel.
The water temperature in the GTMC in the standard mode is maintained at approximately +22...+32°C, with local elevation in hot sections to +35...+45°C. In some areas near the entrance of the hot stream, it is possible to heat water for a short time to +50...+80°C, which may even partially reduce biological activity, but does not make water drinking water without purification.
The upper channel is closed with light selective plates that reflect the sun's rays and allow heat to be released in the infrared range.
- Terminal cooling. Each terminal is equipped with cooling towers, heat exchangers, pumps, booster compressors, turboexpanders, and backup chillers. In normal operation, most low-grade heat is rejected passively through the HTMC.
Gradiers and heat exchangers conduct flow CO₂ after the GTMC from approximately +22...+35°C to +15...+25°C. When necessary, the reserve chillers should reduce the temperature to -5...+5°C before being fed into the deep collectors. Chillers are not used as a primary permanent mode, but as a peak, emergency or seasonal reserve.
- Booster compression and turbo-de-tender. The next terminal CO₂ is cooled but under high pressure. It can then be directed to the turbo-de-tender, where part of the compression energy is recovered, and the temperature is further reduced by expanding approximately to -10...+5°C depending on the pressure, The cost and phase required.
After that CO₂ is fed into the collector tunnels of the GATES with the required temperature, pressure and phase state. This cycle is not a free energy source: the compressor is running, the channel is shedding the heat of compression, and the turbocharger is only partially restoring the energy used. The useful result is a more cold flow with less load on the active cooling units.
- Redundancy and bidirectionality. The coil pipelines are designed with redundancy and bidirectional flow. If one circuit is damaged, the flow is rerouted through a backup pipeline or a neighboring terminal. The direction of CO₂ flow can be changed depending on thermal load, emergency mode, and the condition of individual sections.
- Maintainability. The HTMC is divided by gates at approximately kilometre intervals. If a section is damaged, the segment is isolated and pumps lower the water to the minimum operating level, or the section is partially drained. After depressurization, repair crews or robotic systems can access the coils without shutting down the entire main line. During repairs, cooling is maintained by backup loops, reversing the flow, increasing heat exchange through neighboring terminals, and temporarily operating chillers.
- Limited water management function. The GTMC can perform a secondary water-economy function. With a constant east-west slope, the canal is capable of maintaining slow, self-moving water, sections washing, and regulated discharge of excess.
Night equatorial rains can be used to fill the canal through water pits, dams, filters and spillways. Since water does not come into direct contact with CO₂, after local filtration it can be used for limited irrigation, technical water supply of terminals, fire reserves and green protection zones.
This function remains secondary: water is only allowed within the limits that do not violate the main task of the GTMC cooling CO₂ and maintaining the thermal stability of the GATES.
- What is the value of StarRoad. Deep collectors, heat pumps, terminal coolers, gridirons, booster compressors, turbo-de-tander and spare chillers form a single distributed heat management system. It reduces dependence on local refrigeration machines, increases failure resistance, allows for redistribution of heat flows between terminals, and makes deep acceleration tunnel laying more realistic.
The surface cooling system also enhances the economic value of StarRoad: a linear belt of terminals, service roads, power stations, waterways is formed along the route, industrial sites and irrigated agricultural areas.
Integration with technical tunnels and ground terminals
- Integration with the GATES. Under each sloping tunnel, at a depth of additional 10-20 m, collector tunnels of the GATES are passed for pre-freezing and stabilizing the rock at the construction stage and subsequent generation of energy.
- Ground terminal complex. Each sloping tunnel on the surface is completed by a multifunctional ground terminal. Each of the 40 terminals is an independent node that includes:
- Ventilation and gas purification complex to maintain air regime in the tunnel and remove exhaust air.
- The construction base with storage, overloading and temporary storage of modules, soil and building materials.
- The administrative and household for the placement of shift staff (dispatchers, rest rooms, workshops, warehouses).
- GATES — Geothermal power station and cooling unitsThe electricity generated by the gas pipeline is the energy efficiency of the gas pipeline.
- Capture and processing station CO₂ (DAC). Direct Air Capture (DCC) provides a closed cycle for the GATES: the extracted CO₂ is liquefied, purified and fed into deep collector tunnels as a heat carrier.
- Connection point to external energy networks and communications (reserved power, broadband channel).
Strategic importance
In addition to power supply and thermal stabilization, a key function of the system is to make safe and economical construction of the main accelerator tunnel at extreme depths (5–8 km and deeper) fundamentally possible. Active management of the thermal field and removal of geothermal heat flow eliminates temperature constraints that would otherwise make such depths impractical. This, in turn, enables the optimal S-shaped route geometry with large radii of curvature needed for a gradual climb and for the shuttle to exit at ~5–6° above the horizon while keeping loads on cargo and crew within acceptable limits (~4g) over the 2050 km route. GATES is therefore a technological foundation not only for the energy system, but also for the overall ballistic optimization of the StarRoad trajectory. The entire complex is excavated by a fully robotic fleet of micro-TBMs.
Power and scale
- The cost of one station 2.5 GW: $2.0–3.0 billion.
- Cost of 40 stations: $80–120 billion.
This assessment is confirmed by the lower limit of costs for Russian GeoTES (according to ITURUP about $650/kWt) and the upper limit for complex projects ($1,500/kWt).
The calculation is based on the upper estimate of the total power of the GATES in 100 GW. The actual available power can only be estimated after geological exploration and can be much lower, up to units of gigawatts. In this case, the funds released go to the construction of alternative energy sources.
Environmental and regional functions
StarRoad is implementing an active environmental service model. The project is the world's largest stationary consumer of atmospheric CO₂, which in supercritical condition is a permanent working body in the closed system of the GATES. Millions of tons of carbon dioxide are being taken out of the atmospheric cycle and locked in a technological outline for centuries. This makes StarRoad a powerful climate engineering tool that offsets the carbon emissions of entire industries.
The GTMC is not just a component of the GATES cooling system, but also a dual-purpose transcontinental infrastructure that benefits the region:
- Irrigation. The drainage canals allow water to be used to irrigate agricultural land along the route, turning the arid areas into the green belt of Africa.
- The natural addition. The canal is automatically filled by frequent equatorial rains.
- The gravitational flow. Due to the natural slope of the terrain (3400 m to the east → 0 m to the west), water moves through the canal alone without pumps, providing free circulation.
- The micro-GES. The rise in heights along the canal allows for a cascade of micro-hydroelectric power plants to generate additional renewable energy for local networks and self-sufficiency.
Thus, StarRoad becomes not only a transportation but also an agro-energy platform integrated into the sustainable development of the region.
The GATES and the power station network provide the surplus green energy not only to the accelerator, but also to nearby cities, industrial enterprises and farms.
Technical perpendicular side tunnels system
To support construction, ventilation, repair and evacuation, 40 inclined transport tunnels are built along the route at intervals of about 50 km (30° inclination; elliptical cross-section ~17.5 × 12.5 m). They are excavated by the same tunnel-boring complex used for the main tunnel and connect the surface to the main line at depths of up to 8 km.
- Logistics is what it is. Provide an independent evacuation route for personnel and crew at an emergency stop (Alarm-2). Unlike vertical shafts, the sloping tunnel allows self-propelled machinery to be used to evacuate dozens of people in one flight.
- Safety. They provide a second independent evacuation route for personnel and crew in the event of an emergency stop (Alarm-2).
- It's scalable. The sloping tunnels serve as a base for connecting future parallel lines of StarRoad. They can drill horizontal branches into new accelerating tunnels, turning the network of approaches into a constantly growing transportation frame.
- Integration with the GATES. Under each sloping tunnel, at a depth of additional 10-20 m, collector tunnels of the GATES are passed for pre-freezing and stabilizing the rock at the construction stage and subsequent generation of energy.
Ground terminal complex
Each sloping tunnel on the surface is completed by a multifunctional ground terminal. Each of the 40 terminals is an independent node that includes:
- A ventilation and gas purification complex to maintain air conditioning in the tunnel and remove exhausted air.
- A building base with storage, reloading and temporary storage of modules, soil and building materials.
- Administrative and household building for shift staff (dispatchers, rest rooms, workshops, warehouses).
- Geothermal power station and cooling facilities integrated into the GATES's common grid that use and manage the heat carrier deep collector tunnels.
- Capture and processing station CO₂ (DAC). Direct air capture (DAC). The closed cycle of the GATES is provided: the extracted CO₂ is liquefied, purified and fed into deep collector tunnels as a heat carrier.
- The connection point to the external power grid and the communication (reserve power, broadband channel).
- Road access (automobile or railway branch) for connecting to the regional transport network.
- Evacuation point (exit to the surface), equipped with a point of emergency medical assistance and a helicopter platform.
Legal and environmental flexibility
The inclined geometry of the technical tunnels allows surface terminals to be located outside protected areas (national parks, nature reserves and water-catchment zones), even where the StarRoad main line passes deep beneath them. This removes the principal legal obstacle to routing the main line beneath protected areas, because no infrastructure has to be built within park boundaries. Each terminal can be placed on the nearest unprotected land and connected to the tunnel by an inclined shaft, simplifying approvals, reducing environmental impact and eliminating the risk of direct disturbance to protected ecosystems.
Energy supply and storage system
The StarRoad accelerator power supply system is built as a three-level network that provides:
- Guaranteed reservation (refusal of units does not lead to a stop),
- Adaptive rate of return (from seconds at start to microseconds at finish),
- Minimum length of power cables (loss and inductivity reduction).
The topology levels
Level 0: Primary storage (terminals)
- 40 terminals, each with a park of gravity storage, a hydroelectric power plant (micro-hydroelectric power plant on the channel) and lithium-ion batteries (BESS).
- Total capacity for the terminal: ~5–9 GWh (all ~360 GWh on the track).
- Delivery: a high voltage (up to 100 kV) continuous current through the main cables to the technical tunnel.
Level 1: Segment controllers (50-km segments)
- The trail is divided into 41 segments (by 50 km; the last 50 km to the gate).
- Each segment has a main distribution controller that receives energy from two adjacent terminals (interrupted reservation).
- The segment controller distributes energy across the kilometre energy blocks (by 1 km each), synchronizing their work.
Level 2: Kilometre energy blocks
Each kilometer block has a local controller that:
- It's powered by a segment controller.
- manages buffer lithium-ion batteries (located under the walls of the main tunnel),
- manages switchable winding sets connected through flywheels and supercapacitors (located in dedicated niches behind the tunnel walls).
Two independent channels from the segment controller to each kilometer block provide reservation.
The architecture of cableways
- Mainline cables (Level 0→1): are laid in a three-metre technical tunnel (service tunnel) running parallel to the main tunnel at a distance of 3 m.
- Distribution along the route: from each terminal, cables run 50 km in both directions (100 km in total from the terminal), overlapping the service areas of neighbouring terminals. Thus, each segment is supplied by at least two terminals (neighbours), providing 100% redundancy.
- The main tunnel is open: Each 1 km, the cables are removed from the technical tunnel mainly through the seal passages and connected to the kilometer block controller.
- Distribution within the block: after the controller, the power supply is divided into two parallel paths:
- Tract A: for buffer lithium-ion batteries (capacity ~0.5–1 GWh per block, for smoothing secondary peaks).
- Path B: power is supplied to switchable winding sets through flywheels (kinetic energy storage) and supercapacitors installed behind the tunnel walls.
Three-zone discharge-rate adaptation
The propulsion profile of the shuttle is optimized so that the peak power per single pack of wrappers is the highest at the beginning (where no super short pulses are required), and decreases towards the end of the track. This allows you to use different types of storage and switching equipment in different zones:
| Zone | Route section | Discharge characteristics | Storage/switching technology | Reason |
|---|---|---|---|---|
| Zone I (low speed) | 0 – 200 km | Seconds to milliseconds | Lithium-ion batteries + standard IGBT inverters | The shuttle moves slowly; the transit time over one kilometre is >0.1 s. Operation directly from BESS without buffers is possible. |
| Zone II (medium speed) | 200 – 1000 km | Milliseconds to microseconds | Buffered lithium-ion storage + flywheels, SiC inverters | The shuttle is gaining speed; faster switching is required, but mechanical flywheels are still viable. |
| Zone III (high speed) | 1000 – 2000 km | Microsecond pulses | Ionistors (supercapacitors) + fast thyristor switches (GTO/IGCT) | The time of the kilometer drops to 0.09 s. Only supercapacitors and nanoseconds-response ionistors can stabilize the pulse. |
It 's important . In Zone III, the energy required is less per kilometer than in Zone I (due to the decrease in acceleration), which reduces the load on the elements despite higher demands on the yield speed.
Reservation and emergency stability
- Duplicate the controllers: Each segment and kilometer controller has a hot reserve (two identical plates with independent power supply).
- Intermittent feeding: Each kilometer block can receive energy not only from its segment controller, but also from neighbouring ones (through backup cables in the technical tunnel).
- Local winding redundancy: each kilometre block has three independent winding sets that are switched alternately. If one set is damaged, the other two continue operating, providing acceleration at lower efficiency but without stopping.
- Disconnect in an emergency: When a short shutdown or overheating is detected, the kilometer controller disconnects the power supply from its block and isolates it through intersectional locks without affecting the adjacent blocks.
Material implementation and conclusions
| The element | Place of location | The function |
|---|---|---|
| Primary storage | On the surface (terminals) | Long-term storage of energy (360 GW·h). |
| Highway cables | Technical tunnel (3 m) | Transferring power from terminals to reserved segments. |
| Segment controllers | Niches in mainly tunnel (each 50 km) | Distribution of energy over 10 kilometers, synchronization. |
| Buffer lithium-ion batteries | Under the walls of the main tunnel | Smoothing secondary peaks in Zones II. |
| Flywheels | Behind the tunnel walls (Zone II) | Buffer for millisecond pulses. |
| Ionizers (supercondensers) | Behind the tunnel walls (Zone III) | Microsecond stabilization, compensation for failure. |
| Local controllers (kilometers) | In the niches, every 1 km | Control of the switch, monitoring of the condition, buffer control. |
| Winding the accelerator | The inner surface of the tunnel | Creating a magnetic field to deflect the shuttle. |
The advantages of energy supply architecture
- A smooth distribution of load. Peak power is not required simultaneously over the entire length of the tunnel: at the beginning slow pulses, at the end short but less powerful.
- Redundancy at all levels. Failure of one terminal, controller, or even an entire 50-km segment does not stop the system — neighbouring terminals and segments compensate for the energy shortfall.
- The flexibility of the scale. The addition of new parallel StarRoad lines does not require a redesign of the power system just lay additional mainline cables in the existing technical tunnel.
- Cost optimization. Expensive supercapacitors and flywheels are used only where they are actually needed (the final sections), while cheaper lithium-ion batteries are used at the beginning of the route.