How it differs and what it changes

Comparative overview

How StarRoad differs from rockets, launch loops, space elevators, StarTram, SpinLaunch and other concepts.

Alternative launch systems: their problems and the StarRoad approach

Concept	Key problem	What StarRoad changes
Orbital ring	Potentially the highest throughput, but construction already requires a developed orbital industry, shipyards, energy and mass delivery of materials.	StarRoad can serve as transitional infrastructure: it first creates cheap super-heavy cargo flow and orbital shipyards, which then make an orbital ring a realistic successor.
Starship class	Propellant consumption, stages, orbital refuelling, thermal protection, limited throughput and expensive logistics above LEO.	Acceleration comes from a stationary system; a single flight delivers thousands of tonnes to high orbits without a chain of refuelling operations and many launches.
Falcon 9 / Falcon Heavy	Mature but still rocket-based expeditionary logistics: limited GTO/GEO payload, stages, propellant and high cost per kilogram.	Transforms the task from individual launches into an infrastructure corridor: large modules, regular flow and low cost after amortisation.
Air launch	Mass is limited by the carrier aircraft; the niche is small satellites, with dependence on weather, air corridors and a small upper-stage rocket.	Does not depend on an aircraft or high-altitude release; it scales through route length, energy and shuttle size rather than aircraft payload capacity.
Laser Lightcraft / beamed launch	Atmospheric attenuation and turbulence, clouds, adaptive optics, the need for an extremely powerful laser and perception of the laser as a weapon.	Does not transmit launch energy through the atmosphere: energy is supplied in a closed tunnel, while the atmosphere is crossed by the inertia of a massive shuttle.
Skylon / SABRE / SSTO	Precooler, engine life, thermal protection, a strict dry-mass balance and the need for one vehicle to be an aircraft, rocket and spaceplane simultaneously.	Separates functions: acceleration and energy remain on the ground, so the shuttle need not carry the entire launch-energy system.
Helion-type fusion spaceplane	No compact fusion reactor with thrust above vehicle weight exists; mass, radiators, safety and certification for atmospheric flight remain uncertain.	Does not require a fusion breakthrough for launch: it uses existing and scalable maglev, tunnel, vacuum, storage and thermal-management technologies.
StarTram Gen‑1	High-g profile, cargo specialisation, an external or mountain vacuum tube, a plasma window and restrictions on fragile payloads.	Uses a long underground route and a heavy shuttle, producing lower specific aerodynamic loads, accommodating large completed structures and supporting a wider payload class.
StarTram Gen‑2	An atmospheric vacuum tube on a suspended or levitated route, plasma windows and an extreme external structure for passenger operation.	The main route is underground; the vacuum is protected by rock; exit occurs through a high-altitude ground gateway and a short controlled transition between media.
Lofstrom launch loop	An active dynamic loop requiring continuous stabilisation, an ultra-high-speed rotor and system-wide accident risk.	Underground, passively protected infrastructure; pulsed operation rather than continuous active support; accidents are localised by segmentation.
Space fountain	A vertical active tower depends on a continuous mass stream; loss of the stream removes support and causes collapse.	The structure is not supported by an active stream: the main system is embedded in rock and energy is used in pulses during launch.
Space elevator	Tether material, extreme length, vulnerability to debris and micrometeoroids, slow cargo flow and status as a global target.	Requires no supermaterial; uses tunnels, maglev, power systems, superconductors and terrestrial heavy engineering.
Skyhook / momentum-exchange tether	Rockets or suborbital vehicles are still needed to reach the interception point; frequency is limited and rendezvous precision, reboost and orbital dynamics are complex.	Immediately creates a mass flow of heavy cargo to high-energy orbits; a skyhook can later complement the system but is not a required first stage.
SpinLaunch	Extreme g-loads, small payloads, vibration, limits on electronics and the need for an upper-stage rocket.	Designed for super-heavy cargo and large completed structures; long acceleration lowers g-loads compared with a centrifuge.
Mass driver / electromagnetic gun	On Earth, atmosphere, g-loads and final insertion are obstacles; on the Moon the concept is more favourable, but it requires an existing lunar infrastructure.	Provides terrestrial maglev acceleration in vacuum on a controlled route, with a heavy reusable shuttle and direct orientation towards GEO/EML cargo flow.
Gunpowder or gas space gun	Extreme g-loads, a barrel, a ballistic projectile, risk of impact, a small payload class and the need for final insertion.	Replaces an impulsive shot with long, controlled electromagnetic acceleration; the vehicle remains a reusable shuttle rather than a disposable projectile.

Complete comparison matrix

Project / approach	Core idea	Current status	Target orbit	Payload per flight	Launch frequency from one system	Total throughput	Scalability	Payback / business model	Capital expenditure (CAPEX)	Delivery cost to GEO (USD/kg)	Safety / accident risk	Environmental footprint	Main vulnerability	Areas requiring validation	Technological maturity and feasibility (1-10)	Economic viability (1-10))	Performance in terms of risks and safety (1-10)	Cultural acceptance (1-10)	Political feasibility (1-10)	Overall probability and schedule of implementation, subjective percentage analysis	Sources / links
StarRoad / SR	Underground vacuum electromagnetic highway ~2050 km: running magnetic field, launch mass of AstroLiner/AstroLiner-S ~15000 tonnes, discharge to ~11 km/s, GATES/reserve energy and accumulators. The start energy is taken out into the infrastructure; the transition from vacuum to atmosphere is closed by a gas dynamic gradient barrier.	Pre-project architecture, baseline feasibility concept and roadmap. The complete system has not flown, but maglev, superconductors, vacuum, pulsed power, hypersonics, tunnelling and thermal management have real analogues. The main gap is integration and scale.	Direct output to GEO/GSO, EML1/2/4/5 and high-energy trajectories. AstroLiner-S: chemical uptake/correction; mature AstroLiner: EMPD/nuclear-electrical contour.	~10 000 t PN at the launch mass of the boat ~15 000 t.	Pilot 1–2/month; mature 1 line ~200–300/year; several lines 500–1500+/year.	120–240 thousand t/year start; ~2–3 million t/year 1-line in maturity; 5–15+ million t/year network.	Very high after the first line: parallel tunnels, repeatable gateways and a shared energy-industrial corridor.	The launch of the KSE, the orbital CEDs, the shipyard, the EML4/5 modules; the revenue from transportation, the GATES, the KSE and the orbital logistics.	$225–365 billion first line; median ~$295–300 billion.	$80–120/kg start; $10–20/kg after 6–10 years; mature network ~$0.3–3/kg on GSO/high orbits.	Low calculated risk and low risk in normal operation through segmentation, Alarm protocols and passive safety, subject to validation and small-scale testing.	Minimal: geothermal energy + direct air capture + space-based solar power	The initial funding of Phase 0 and the political window, the huge CAPEX, the geopolitics of Africa, the international legal status, political trust, the counterintuitive perception of the scale and security of the project.	Geological exploration (8 km), gas dynamic gateway, passive levitation and accelerator system; vacuum; evacuation; energy balance; shock wave and its influence; form aerothermodynamics. Component integration and scaling.	6/10 Everything uses existing technologies (TPC, Maglev, EGS), but integration is unprecedented.	9- What ?10 Dual model: energy partially pays off infrastructure for 5–7 The potential profit is > a trillion dollars per year. 30 years.	8/10 Alarm protocols (1/2/3), segmentation, no onboard jet fuel at the launch site, passive inductive self-stabilization of the shuttle in the tunnel when the active systems fail or shut down. An accident doesn't destroy the whole system.	7- What ?10 It's futuristic, but the analogy with the Trans-Siberian Canal makes the project understandable.	5- What ?10 Track through 3 The project is being implemented by the National Centre for the Development of Climate Change (CERN) and the National Centre for Climate Change (CERN). 90% of land disputes.	The probability: 60High technical and economic feasibility, but CAPEX and policy hold back. 25–40- What ?	StarRoad project
Orbital ring	An active ring megastructure around Earth. In Birch’s concept, a rotating ring with stations and elevators; in the SR documentation version, a transport ring and a GEO port ring, with the transport ring fitted with rotors and anchored on one side to the planetary surface and on the other to a static geosynchronous ring.	Concept / distant astroengineering. No large demonstrator; requires a developed orbital industry.	LEO↔GEO, GEO port and EML transport.	Theoretically tens to thousands of tonnes per lift or container, depending on architecture.	Near-continuous flow after commissioning.	Potentially millions to tens of millions of tonnes per year.	Extremely high, but only after mass orbital industry exists.	Lift tariffs, orbital ports, energy, communications and industry.	Hundreds of billions to trillions of dollars; lower with extraterrestrial material production.	Theoretically <$1–10/kg after depreciation; the first generation is higher.	Low after construction	Electricity	Requires an existing space industry	Construction in space and stabilisation	2- What ?10 It requires a mega-building in space of thousands of launches.	2- What ?10 It's unrecoverable without a cargo stream, which doesn't exist without the ring itself.	4/10 After construction safe, but construction in radiation and garbage conditions.	5/10 It's perceived as the next step after space industrialization, but far too far away.	2/10 Requires global consensus and dozens of states.	The probability: 5%. Technologically and economically unrealizable in the near future 100 Without StarRoad or something like that, it probably won't be available. 100+ years.	https://launchloop.com/slides/launchloop.pdf
Starship class	A fully reusable chemical super-heavy rocket: Super Heavy + Starship, methane/oxygen and orbital refuelling.	Flight testing and development. Real prototypes fly, but regular reusability and orbital refuelling have not yet been demonstrated as an operational system.	Direct to LEO; GTO/GEO, Moon and Mars through refuelling or tugs.	>100 t to orbit in a fully reusable configuration on SpaceX; GEO depends on refueling.	The target is high frequency; in 2026 it's still the testing/growth phase.	Hundreds to thousands of tonnes per year during early operation; tens of thousands of tonnes per year at high frequency.	High manufacturing and launch-site scalability; constraints are propellant, licensing and thermal-protection maintenance.	Starlink, NASA/Artemis, government contracts, commercial cargo and lunar logistics.	Many billions of dollars in R&D and infrastructure; the exact public estimate changes.	The target order $100–1000+/kg for high orbits at full reuse/refuel; the actual price has not yet been proven.	Average (1–2% accident at start)	CO₂ and soot, although methane is cleaner than kerosene	Complex reusability, thermal protection and refuelling	Long-duration propellant storage and landing	8/10 It's already flying prototypes.	6- What ?10 There's a satellite market, but the price of GSO is still high.	6/10 — 1–2% of accidents is acceptable for missiles.	9- What ?10 The most media-friendly project.	7- What ?10 Private companies avoid bureaucracy, but there are military restrictions and licensing issues.	Probability: 80%. Already working, there are good chances of getting it right, but it's leaning towards the economic ceiling.	https://www.spacex.com/vehicles/starship
Falcon 9 / Falcon Heavy	Modern chemical rockets with partial multiplexing capabilities. Falcon 9 working carrier; Falcon Heavy heavy tri-block version.	The Falcon 9 one of the most reliable modern carriers; the Falcon Heavy flies less frequently.	LEO, SSO and GTO; direct GEO and high-energy trajectories are possible in selected profiles.	Falcon . 9From: 8.3 Falcon Heavy: tens of tons of GTO in the disposable/partially reusable profile.	High for the Falcon 9; low/middle for the Falcon Heavy.	Thousands of tonnes per year to LEO across the system; substantially less to GTO/GEO.	Good, but rockets remain discrete expeditionary logistics with limited payload per flight.	Commercial satellites, Starlink, government contracts, rideshare and scientific missions.	Development is already being amortised; total infrastructure is in the billions of dollars.	Falcon 9 standard GTO of the order of $13k+/kg; Falcon Heavy GTO in the best profiles several thousand $/kg, direct GEO higher.	Average (1–2%)	CO₂ and soot	Limited payload and high cost	Higher frequency and lower price	8- What ?10 It's been around for decades.	7/10 Stable revenue, but the price does not allow to create industrial cargo flow.	7/10 Reliable, but accidents happen: 1% is statistically one accidental launch on 100 launches.	9/10 Famous and reliable.	7/10 Launching is regulated, but companies know how to work with bureaucracy.	Probability: 100%. They're already working. They'll be used for decades in their niche.	https://www.spacex.com/vehicles/falcon-9/; https://www.spacex.com/assets/media/Capabilities%26Services.pdf
Air launch	The carrier aircraft raises the rocket for [10–15 km], then the rocket is detached.	Pegasus exists and is used occasionally; Virgin Orbit/LauncherOne closed; Stratolaunch shifted towards hypersonic testing.	LEO/SSO for small spacecraft; GSO through small upper stages is economically weak.	The Pegasus XL was up to ~454 kg LEO; the LauncherOne was a ~300 kg LEO-class.	Low: individual or rare launches.	Tonnes per year, not thousands.	Limited by aircraft and rocket mass; scales poorly to heavy payloads.	Niche urgent and flexible small satellites, military and scientific missions.	Low to medium CAPEX relative to spaceports; high operating cost.	Practically uncompetitive for GSO; often tens of thousands of dollars per kilogram to LEO.	Medium, because of rocket separation	Aviation kerosene + rocket propellant	Micro-payload and weather	Increasing payload mass	7/10 Already working.	5- What ?10 Very expensive per kg. Only for small satellites.	6/10 Division risk, but manageable.	5/10 Interesting as an aviation trick, but not as an industry.	6/10 We need air bases and corridors, but this is a national issue.	Probability: 100%. Will exist as a niche for small military and scientific satellites.	https://www.northropgrumman.com/what-we-do/space/launch-vehicles/pegasus; https://science.nasa.gov/blogs/swift/2026/06/15/rocket-attached-to-aircraft-for-katalyst-nasa-swift-boost/
Laser Lightcraft / beamed launch	A ground-based laser array heats air or onboard working fluid; first-stage energy is supplied from the ground.	Experimental small models and analyses; no orbital system has been built.	Theoretically LEO; GSO through subsequent stages or tugs.	Initially grams to kilograms; heavy payloads are extremely distant.	Theoretically high with a completed laser; not demonstrated in practice.	From kilograms per year in demonstrations to hypothetical thousands of tonnes per year.	Requires enormous lasers, adaptive optics, atmospheric control and beam safety.	Microsatellites, urgent launches and military/scientific demonstrators.	Billions to tens of billions of dollars for an orbital-class laser array.	Theoretically <$100–1000/kg for small masses; GSO is unproven.	High, because the laser is a weapon	Electricity	Atmospheric laser attenuation and clouds	Laser power and focusing	4/10 Lasers exist, but the power and accuracy at 100 km have not been achieved.	4/10 Energy is cheap, but the laser installation is expensive, and the load is small.	3/10 Laser weapons of mass destruction when not aimed.	4/10 Interesting, but too science fiction.	3/10 Countries will not allow the installation of megawatts-class lasers without military control.	Probability: 20%. Remains a laboratory exotic. Requires a breakthrough in adaptive optics. Duration/status: 30–50 years.	https://ayuba.fr/pdf/myrabo1998a.pdf; https://ntrs.nasa.gov/api/citations/20010020022/downloads/20010020022.pdf
Skylon / SABRE / SSTO	A single-stage spaceplane: SABRE operates as an air-breathing engine to hypersonic speed and then switches to rocket mode.	The pre-cooling system showed Mach 5 conditions; the full engine and Skylon were not flying; Reaction Engines entered administration.	Direct to LEO; GTO/GEO through an upper stage or refuelling.	Classic Skylon ratings: order ~15 t LEO; to GSO is significantly smaller.	Designed for aircraft-like operations, but not demonstrated.	Hundreds to thousands of tonnes per year with a fleet, not millions.	Scales through vehicle and runway production, but the engine and thermal protection are complex.	Commercial cargo, passenger/fast transport and government contracts.	Many billions of dollars in R&D plus production; exact CAPEX unconfirmed.	Estimated $2k10k+/kg on GSO with displaced blocks; low LEO-prices have not been proven.	Medium, because of engine failure	Hydrogen, clean	Precooler, thermal protection and engine life	Cooling machine on Mach 5, heat protection	4/10 SABRE refrigerator Outstanding engineering, but not yet fully tested.	4- What ?10 Too difficult and too expensive for the SSTO.	5/10 Cooling rejection = critical rejection of hypersonic.	6/10 Beautiful project, but too risky.	5/10 Based in the UK, but without global support.	The probability: 30%. Technically interesting, but economically losing Starship and StarRoad. 15–20 years.	https://www.esa.int/Enabling_Support/Space_Engineering_Technology/Air-breathing_engine_precooler_achieves_record-breaking_Mach_5_performance; https://aerospaceglobalnews.com/news/time-runs-out-for-reaction-engines-as-it-enters-administration/
Helion-type fusion spaceplane	A hypothetical SSTO using a compact fusion reactor and high-thrust air-plasma or electromagnetic engines.	Systemically speculative: compact fusion has not been demonstrated as a high-power-density aerospace engine.	Theoretically LEO/GTO/GEO and, with development, interplanetary trajectories.	Uncertain: tens to hundreds of tonnes in a successful version.	Theoretically aircraft-like high frequency.	Potentially high, but dependent on the reactor.	If the reactor is solved, scaling by fleet; until then there is no engineering base.	Ultra-low-cost transport, energy, military and interplanetary markets; currently no testable model.	Tens to hundreds of billions of dollars in R&D vehicle CAPEX unknown.	Hypothetically <$100–1000/kg; not confirmed.	Medium to high, because of reactor depressurisation	Hydrogen / helium-3 (clean)	Reactor mass, radiators and fusion not yet achieved	Compact fusion, radiation protection and reactor reliability.	2/10 Compact thermonuclear reactor and gravity-surpassing magnetic plasma engines have not been developed in the laboratory.	3- What ?10 The cost of the reactor and fuel, including helium, is3- What ?	5/10 De-harmonisation of the reactor in the atmosphere instant engine shutdown and fall. But it's more environmentally safe than, say, a nuclear reactor.	4/10 Mass radiophobia is possible.	3/10 Not regulated as it does not exist.	The probability: 10%. Not feasible in the foreseeable future without a breakthrough in the thermodynamics. 50+ years, if at all.	https://www.helionenergy.com/
StarTram Gen‑1	High-g cargo maglev acceleration in a vacuum tube along a high mountain slope; the container exits into the atmosphere at high speed.	A concept with detailed Powell/Maise calculations; no full-scale demonstrator, though components resemble maglev, vacuum and pulsed-power systems.	LEO, polar and low orbits; GSO through a kick stage or tug.	About 35 t the PN at 40 t the apparatus.	10–12 launches/days in the author's estimates.	~128–150 thousand tons per year for one system.	Scalable through multiple lines, but tied to mountains and high-g cargo.	Bulk cargo, propellant, raw materials and structures; not people or fragile equipment.	~$20 billion in estimates 2010; today higher.	Author's estimate ~$43/kg LEO; up to GSO with conditional deduction ~$100–300+/kg.	High (overloads 30g)	Electricity	Overloads 30g, tower at 20 km	Magnetic levitation of the tube	3/10 Requires a giant levitating tube and a plasma window.	4/10 It may be economical for cargo, but the market is small.	5/10 Cascading superconductivity failure. More secure than a Gen2 tube without a suspension in the atmosphere.	4/10 Interested in engineers, but not the public.	5/10 Requires land, but not global consensus.	The probability: 15%. Too difficult for cargo; the passenger version is even more difficult. 15–30 years.	https://startram.com/wp-content/uploads/2020/12/StarTram2010.pdf
StarTram Gen‑2	A people-capable StarTram with a longer route, low g-loads and a levitated or supported exit tube at high altitude.	More ambitious than Gen-1: requires a long support/levitating pipe and passenger mode.	LEO and beyond through final insertion.	Tens of tonnes per flight, depending on the capsule.	Many launches per day with a completed line.	Hundreds of thousands of tonnes per year, possibly more.	Limited by suitable sites and the complexity of the high-altitude tube.	Passenger and cargo transport, orbital infrastructure and tourism.	Estimated tens to hundreds of billions of dollars.	Theoretically $100–500/kg to high orbits; not proven.	High, because of levitated-tube instability	Electricity	Tube levitation and plasma window	20km tower, plasma window	3/10 Technically more complicated Gen-1: the pipe must levitate at 20 km.	4/10 More expensive Gen-1, but the payback is unclear.	3/10 Instability of the suspended outer pipe due to exposure to external conditions. Cascading refusal of superconductivity.	5/10 The passenger aspect is interesting, but the risks are high.	3/10 Requires global funding and political will.	The probability: 15%. Too high risk for humans. 30–40 years.	https://startram.com/wp-content/uploads/2020/12/StarTram2010.pdf
Lofstrom launch loop	Active structure: the super-speed rotor/lens in the shell supports the loop at a height of ~80 km and displaces the loads.	Concept with engineering calculations; no large demonstrator.	GEO, near-lunar, EML and high-energy trajectories in the original concept; LEO requires circularisation.	The classical assessment of 5 t the device/pack.	Up to tens of launches per hour in the original calculations.	Theoretically hundreds of thousands to millions of tonnes per year.	High after construction, but the single structure is large and active.	Mass cargo transport, energy and orbital industry.	Historical estimates of ~$10–30 billion; the current realistic range is higher.	Theoretically $3–30/kg; GSO/near-lunar are indicated as target trajectories.	Extremely high, because of rotor failure	Electricity	Rotor failure is catastrophic; continuous power required	Rotor safety and loop containment	2/10 Requires a continuous rotor movement at 14 km/h. Any stop is a disaster.	3/10 The continuous energy losses make the economy questionable.	1/10 A rotor rupture destroys everything for hundreds of miles.	3/10 Known in narrow circles, but too dangerous.	2- What ?10 Nobody will allow the building of a kinetic bomb.	The probability: 5%. Unrealized for safety and energy reasons. 30–40 years.	https://launchloop.com/slides/launchloop.pdf
Space fountain	A vertical active tower supported by a stream of pellets or mass that is deflected at the top to create supporting force.	Theoretical active structure; no large prototypes.	Suborbital/LEO support; GSO through additional systems.	Theoretically tonnes to tens of tonnes.	Potentially continuous or frequent operation.	Theoretically thousands to hundreds of thousands of tonnes per year.	Limited by the stability of the vertical active system.	Lifting cargo to an upper platform, launching upper stages, energy and observation.	Tens to hundreds of billions of dollars, with very high uncertainty.	Not demonstrated; theoretically low under high utilisation, but GSO requires a second system.	Extremely high, because stopping the stream causes failure	Electricity	Stopping the stream means immediate collapse	Control of flow at 200 km	1/10 Requires nanosecond synchronization of the flow at 200 km.	2/10 Huge losses of energy to circulation.	1/10 Crash disaster at 200 km.	3/10 Too difficult to understand.	1- What ?10 Nobody's gonna let you build a hanging tower.	Probability: 1%. Purely theoretical exotic. Duration/status: 50+ years/almost never.	https://en.wikipedia.org/wiki/Space_fountain
Space elevator	A tether extends from the surface beyond geostationary orbit; climbers carry cargo and a counterweight holds the system taut.	Concept. The main stopper is material and production of an ultra-long, defect-tolerant tether.	GSO as the base point; interplanetary release from upper sections.	Kilograms to tens of tonnes per climber, depending on ribbon and power.	Continuous climbs at intervals; slower than rockets.	Hundreds to thousands of tonnes per year initially, increasing with ribbon expansion.	Expansion is possible after the first ribbon, but tether vulnerability remains.	Lift tariffs, GSO logistics, energy, communications and tourism.	Tens to hundreds of billions of dollars, but the material is not ready.	Theoretically $10–100/kg; actually not achievable without material.	High, because tether failure may trigger a Kessler cascade	Electricity	Material such as nanotubes and space debris	Tether strength and debris protection	1- What ?10 The material doesn't exist in the industry.	2/10 Even if built, the clampers build about 10 tons a week.	1/10 The cable breaking the risk of destroying all the connected space infrastructure.	5/10 A symbol of futurism, but too fragile.	1- What ?10 Tross global target; terrorism, garbage or micro-meteorites cut it off.5- What ?10I 'm not .	Probability: 1% (50% outside the Earth). Not realized due to material, garbage and safety. Duration/status: 50+ years (outside the Earth) / practically never.	https://www.isec.org/space-elevator-tether-materials; https://ntrs.nasa.gov/api/citations/20060000015/downloads/20060000015.pdf?attachment=true
Skyhook / momentum-exchange tether	A rotating orbital tether captures a suborbital vehicle and transfers momentum to it, then requires reboost.	Tethers have been tested in small missions; no full skyhook has captured cargo.	LEO to higher orbit; potentially part of a chain to GEO/EML.	Hundreds of kilograms to tens of tonnes depending on tether and capture system.	Limited by reboost time and rendezvous windows.	Theoretically thousands to tens of thousands of tonnes per year with a network.	Scales well as a network, but every node requires precise rendezvous.	Interorbital transport, propellant savings and integration with rockets, StarRoad or aircraft.	Billions to tens of billions of dollars for a network.	Theoretically $100–1000/kg in the network; GSO requires several nodes/reboost.	Medium, because of collision risk	Electricity	Capture precision and materials	Materials and capture system	3/10 Requires super-strong materials and precision of capture.	4/10 Can lower the cost of an LLC, but not a GSO.	4/10 Collision with an apparatus risk.	4/10 Interesting, but difficult to understand.	4/10 Requires the launch coordinates.	The probability: 20%. Can be useful as a complement to rockets, but not a base. 20–30 years.	https://ntrs.nasa.gov/citations/20020068839; https://ntrs.nasa.gov/api/citations/20060047739/downloads/20060047739.pdf
SpinLaunch	A centrifugal vacuum accelerator spins a vehicle and ejects it upward; a rocket then completes orbital insertion.	There's a 33-meter suborbital accelerator and test; the orbital system is not implemented.	LEO for small robust cargo; GSO through separate rocket and orbital logistics.	Tens to hundreds of kilograms on the orbital vehicle, depending on upper stage and g-tolerance.	Theoretically high; not demonstrated in practice.	Kilograms to tens of tonnes per year initially, potentially more for small standardised cargo.	Limited by mechanical stress, g-loads and rotor size.	Small satellites, components, propellant and consumables if they withstand the g-load.	Hundreds of millions to several billion dollars for an orbital complex.	Claimed low prices are unproven; GSO is probably uncompetitive without a separate upper stage.	Medium, because of vibration and release failure	Electricity + propellant	Overloads (10 000g), vacuum	Increasing payload mass	5/10 The prototype works, but overloads will kill any sensitive load.	5/10 It's economical for small satellites, but the market is limited.	5/10 Vibrations destroy electronics.	4/10 It's amazing, but it's exotic.	4/10 Military clearance needed: looks like a gun.	The probability: 40%. It will remain a niche for military and low-cost Starlink-like satellites. 5–10 years if it goes into business.	https://www.spinlaunch.com/
Mass driver / electromagnetic gun	A linear electromagnetic accelerator in which coils or rails accelerate a container or vehicle. Particularly attractive on the Moon because of vacuum and low gravity.	Ground, military and laboratory electromagnetic accelerators exist; no space mass driver is operational. A lunar version is more realistic than a terrestrial one.	Moon to lunar orbit/EML; Earth to LEO only for high-g cargo; GSO through tugs.	Ktonnes per shot; lunar concepts 1–10 kg with frequent launches or up to a ton.	From one launch every few seconds for small containers to infrequent large launches.	Moon: thousands to millions of tonnes per year with an established base. Earth: limited by high-g and atmosphere.	High on the Moon; limited on Earth by atmosphere and safety.	Lunar raw materials, construction materials for orbital shipyards, propellant and regolith.	Lunar system: billions to tens of billions of dollars after a base exists; terrestrial system: tens of billions or more.	Earth→GSO is bad. Moon→orbital nodes can be <$10–100/kg after infrastructure.	Low on the Moon	Electricity	Requires lunar infrastructure	Energy and materials	4/10 The technology of mass-drivers is mature, but on the Moon it requires an energy base.	5/10 With a lunar base can be paid for by export.	6/10 The Moon is safe: there is no biosphere.	5/10 Interesting as part of the lunar program.	3/10 Requires an international agreement on the Moon.	The probability: 30%. Only appears after the lunar database is created. 30–50 years with a lunar base.	https://ntrs.nasa.gov/api/citations/19930007725/downloads/19930007725.pdf; https://ntrs.nasa.gov/api/citations/20110007073/downloads/20110007073.pdf
Gunpowder or gas space gun	A ballistic gun or light-gas gun accelerates a projectile or vehicle through a barrel. Historical examples include HARP, SHARP and Project Babylon.	Suborbital altitudes have been demonstrated historically; orbital launch has not. SHARP and HARP ended.	Suborbital trajectories; LEO/GSO only with rocket final insertion and robust cargo.	Historically kilograms to tens of kilograms; large masses require an enormous barrel.	Can fire frequently for small projectiles, but barrel wear imposes limits.	Kilograms to tonnes per year in real versions; not suitable for delicate cargo.	Scales poorly to people or fragile systems; high dual-use potential.	Suborbital research, robust sensors and materials; weak orbital economics.	Hundreds of millions to many billions of dollars for a modern complex.	Practically unjustified for GSO; expensive and niche with an upper stage.	High, because of g-loads and trajectory deviation	Gunpowder / gas	Overloads (>10 000g)	Larger calibre and projectiles	6/10 Technically implemented for suborbits: HARP, SHARP.	3/10 Too expensive for a kilo, no lifting capacity.	3/10 The snare can fall anywhere.	3/10 Interesting as a historical curiosity.	3/10 Military projects are closed.	Probability: 10%. Will be used as a military laboratory device, but not for orbit.	https://secwww.jhuapl.edu/techdigest/content/techdigest/pdf/V20-N03/20-03-Gilreath.pdf; https://www.army.mil/article/205046/new_technology_testing_may_achieve_the_goals_of_harp_space_gun

Composite index

Project / approach	Category	Component technology	Economic model	Safety	Politics/regulation	Culture	Scalability	Overall index	Probability / schedule
StarRoad / SR	Infrastructure launch corridor	6	9	8	5	7	9	7.3	60%; 25–40 years
Orbital ring	Astroengineering structure	2	2	4	2	5	10	4.2	5%; 100+ years
Starship class	Reusable rocket	9	6	6	7	9	7.5	7.4	80%; already being tested / first commercial launches
Falcon 9 / Falcon Heavy	Partially reusable rocket	10	7	7	7	9	4.5	7.4	100%; already working
Air launch	Air-and-rocket niche	7	5	6	6	5	2	5.2	100%; already working
Laser Lightcraft / beamed launch	Beamed launch	4	4	3	3	4	6	4.0	20%; 30–50 years
Skylon / SABRE / SSTO	SSTO spaceplane	4	4	5	5	6	5	4.8	30%; 15–20 years
Helion-type fusion spaceplane	Energy-speculative SSTO	2	3	5	3	4	7	4.0	10%; 50+ years, if at all
StarTram Gen‑1	Cargo maglev	3	4	4	5	4	7	4.5	15%; 15–30 years
StarTram Gen‑2	Passenger maglev	3	4	3	3	5	7	4.2	15%; 30–40 years
Lofstrom launch loop	Active dynamic structure	2	3	1	2	3	7	3.0	5%; 30–40 years
Space fountain	Active tower	1	2	1	1	3	6	2.3	1%; 50+ years / almost never
Space elevator	Tether megastructure	1	2	1	1	5	7	2.8	1%; 50+ years / almost never
Skyhook / momentum-exchange tether	Orbital tether network	3	4	4	4	4	6.5	4.3	20%; 20–30 years
SpinLaunch	Centrifugal accelerator	5	5	5	4	4	3	4.3	40%; 5–10 years if it goes into business
Mass driver / electromagnetic gun	Electromagnetic accelerator	4	5	6	3	5	7.5	5.1	30%; 30–50 years with a lunar base
Gunpowder or gas space gun	Ballistic gun	6	3	3	3	3	2	3.3	10%; already there; not working for orbit

The main difference

StarRoad does not compete with rockets as “another launch vehicle”. It changes the type of system: rockets remain transport vehicles, while StarRoad operates as a launch corridor with capital infrastructure, growing frequency and falling cost after amortisation.

What scale changes

Almost all alternatives are constrained by materials, active dynamic stability, small payload or the need for an already existing orbital industry. StarRoad focuses on terrestrial infrastructure and super-heavy cargo flow as the first step towards orbital industry.