John Paniagua

StarTram: a new approach for low-cost Earth-to-orbit transport

StarTram is a revolutionary concept for low-cost, high volume Earth-to-Orbit transport of passengers and/or cargo. StarTram is an evacuated launch tube that is magnetically levitated above the Earths surface, up to a maximum altitude of /spl sim/18 km above the local terrain. Although the concept is advanced, it is within the limits of existing technology. The launch tube is levitated by the magnetic repulsive force between a set of superconducting (SC) cables attached to the tube and a set of SC cables on the ground beneath. A total current of 14 mega-amps in the levitated cables and an oppositely directed current of 280 mega-amps in the ground cables, produces a repulsive force of 4 tonnes/m at an altitude of 22 km above sea level (18 km above local ground level). These forces levitate a robust 7 meter diameter launch tube with an adequate margin of safety. The launch tube is stabilized, both vertically and horizontally, against the net upwards magnetic force and wind forces, by an array of high tensile strength (e.g., Kevlar) tethers that are anchored to the ground. Traveling inside the launch tube is a reusable StarTram Space Vehicle (SSV) that is magnetically levitated and accelerated to near orbital velocity in an evacuated tunnel at ground level. The SSV carries a set of lightweight SC magnets that inductively interact with a guideway of simple normal aluminum loops that operate at ambient temperature to stably levitate the moving vehicle. A separate AC current winding in the guideway pushes on the SSVs SC magnets, accelerating it. After the SSV reaches 8 km/sec at the end of its 1280 km long acceleration tunnel, it transitions into the ascending, magnetically levitated 220 km long launch tube, in which it coasts upwards to the launch point at an altitude of /spl sim/22 km The SSV then enters the upper atmosphere at a launch angle of 5 degrees. A subsequent 0.34 km/sec /spl Delta/V burn by a conventional LOX-kerosine rocket engine on the SSV inserts it into orbit. For a high-traffic system, StarTram can deliver payloads into orbit at a projected cost of

Maglev Launch and the Next Race to Space

30 per kilogram This includes amortization of the launch complex, vehicle, and energy costs.

SUSEE - ultra light nuclear space power using the steam cycle

A new approach for greatly reducing the unit cost to launch payloads into space is described. The approach, termed Maglev launch, magnetically levitates and accelerates space craft to orbital type speeds in evacuated tunnels at ground level, using superconducting Maglev technology similar to that already operating for high speed passenger in Japan. Two Maglev launch systems are described. The near term Gen-1 Maglev launch system would accelerate heavy cargo craft (-40 tons) to 8 km/sec using electrical energy at a unit energy cost of only 50 cents per kilogram. No propellants would be required. After achieving orbital speed the Gen-1 cargo craft would exit into the atmosphere at a high altitude point (> 4000 meters) on the surface, and climb through the atmosphere to orbit. The aerodynamic deceleration and heating loads during the ascent through the atmosphere appear acceptable. A single Gen-1 facility could launch over 100,000 tons annually at a unit launch cost of less than

MIC - a self deploying magnetically inflated cable system for large scale space structures

50 per kg of payload, compared to present costs of

SUSEE: A Compact, Lightweight Space Nuclear Power System Using Present Water Reactor Technology

10,000 per kg. The longer term Gen-2 system would launch human passengers as well as cargo. To reduce the aerodynamic deceleration and heating loads on the Gen-2 spacecraft, it would transition into a magnetically levitated evacuated launch tube conveying it to a high altitude (-20 km) where the very low atmospheric density would not cause substantial deceleration and heating. A Gen-1 system could be operational within the next 10 years with aggressive funding, and a Gen-2 system within the next 20 to 30 years. Major applications include space solar power satellites for beaming power to Earth and a greatly expanded space exploration program.

Mini-MITEE: Ultra Small, Ultra Light NTP Engines for Robotic Science and Manned Exploration Missions

A near term, ultra lightweight nuclear space power system (SUSEE) using existing water cooled reactor/steam cycle technology is proposed. SUSEE uses an innovative new lightweight condensing radiator that can operate in zero g, with /spl sim/1 m/sup 2//KW(e), 10 times smaller than other concepts. With standard 1000 F, 1000 psi superheated steam, 80% turbine efficiency and 2 atm condenser pressure, SUSEE has 24% thermal efficiency. SUSEE can deliver powers from a few kilowatts to multi-megawatts, with very small reactors (a 1 MW(e) reactor has 40 cm OD). SUSEEs radiator is a flexible assembly of thin metal strips (Al or Be) with internally grooved channels for the steam/water condensate. It can be rolled into a compact launch package and unrolled in space.

Pluto Orbiter/lander/sample return missions using the MITEE nuclear engine

Abstract A new approach, termed MIC (Magnetically Inflated Cable) that enables large, lightweight very strong and rigid space structures is described. MIC would be launched as a compact package of coiled superconducting (SC) cables. After reaching orbit, the cables would be cryogenically cooled and electrically energized by a small power source. The resultant repulsion magnetic forces between the DC currents in the SC cables automatically cause the coiled launch package to self deploy into the final large space structure. The SC cables are held in place by a distributed network of high tensile strength tethers (e.g., Spectra material), creating a very stiff, rigid truss structure that strongly resists bending and torsional, etc. movements, without the need for gravity gradient stabilization. A linear quadrupole (LQ) MIC configuration is described that is suitable for large solar power satellites, space stations, space hotels, propellant tanks, manned Mars spacecraft, etc. The LQ has 2 long SC dipole loops, of horizontal width W, length L, and opposite magnetic polarity, which are vertically separated by distance W, producing a long truss structure of square cross-section (width W) with the 4 SC cables at the corners of the square. The SC currents are opposite in adjacent cables, yielding an outwardly directed net radial force on each cable. The ends of each SC loop experience outwards longitudinal forces. The magnetic forces are very strong, even for modest supercurrents. For example, a 4 meter square truss with I = 250 kiloamp has an outwards radial force of 220 kg per meter of cable. and 5250 kg outwards longitudinal force at the ends of each SC loop. The network of restraining tensile lines can support lightweight structures, including solar panels, propellant tankage, habitat modules, power transmission lines, etc. The design of a 1 kilometer long, 4 meter square cross section MIC truss for solar power satellites is described. The MIC launch package fits within the length/weight constraints of the shuttle bay, and includes all of the helium coolant lines, thermal insulation, and refrigeration equipment required.

A self-sustaining Earth-Mars architecture utilizing Martian colonies based on the North Polar Cap

The SUSEE space reactor system uses existing nuclear fuels and the standard steam cycle to generate electrical and thermal power for a wide range of in‐space and surface applications, including manned bases, sub‐surface mobile probes to explore thick ice deposits on Mars and the Jovian moons, and mobile rovers. SUSEE cycle efficiency, thermal to electric, ranges from ∼20 to 24%, depending on operating parameters. Rejection of waste heat is by a lightweight condensing radiator that can be launched as a compact rolled‐up package and deployed into flat panels when appropriate. The 50 centimeter diameter SUSEE reactor can provide power over the range of 10 kW(e) to 1 MW(e) for a period of 10 years. Higher power outputs are possible using slightly larger reactors. System specific weight (reactor, turbine, generator, piping, and radiator is ∼3 kg/kW(e). Two SUSEE reactor options are described, based on the existing Zr/O2 cermet and the UH3/ZrH2 TRIGA nuclear fuels.

Self-sustaining Mars colonies utilizing the North Polar Cap and the Martian atmosphere.

A compact, ultra lightweight Nuclear Thermal Propulsion (NTP) engine design is described with the capability to carry out a wide range of unique and important robotic science missions that are not possible using chemical or Nuclear Electric Propulsion (NEP). The MITEE (MInature ReacTor EnginE) reactor uses hydrogeneous moderator, such as solid lithium‐7 hydride, and high temperature cermet tungsten/UO2 nuclear fuel. The reactor is configured as a modular pressure tube assembly, with each pressure tube containing an outer annual shell of moderator with an inner annular region of W/UO2 cermet fuel sheets. H2 propellant flows radially inwards through the moderator and fuel regions, exiting at ∼3000 K into a central channel that leads to a nozzle at the end of the pressure tube. Power density in the fuel region is 10 to 20 megawatts per liter, depending on design, producing a thrust output on the order of 15,000 Newtons and an Isp of ∼1000 seconds. 3D Monte Carlo neutronic analyses are described for MITEE rea...

MIC: Magnetically Deployable Structures for Power, Propulsion, Processing, Habitats and Energy Storage at Manned Lunar Bases

Pluto Orbiter/lander and sample return missions are not impossible using chemical propulsion, but are possible with nuclear thermal propulsion. Using the MITEE nuclear engine, a spacecraft could first orbit Pluto, mapping it, and then land at a selected site, 12 years after the departure form Earth. If surface water/ice is available, fresh H/sub 2/ propellant could be manufactured by electrolysis of melt H/sub 2/O using power from the bi-modal nuclear engine, enabling multiple hops to new sites for further data collection. A warm water probe could also be deployed to explore the interior of Plutos ice sheets. After completing exploration, the spacecraft could return samples from Pluto to Earth with a 12-year trip time. Mission architectures and the design of the spacecraft, nuclear propulsion engine, propellant manufacturing unit and warm water probe are described herein.