Use of high-power solar arrays, at power levels ranging from ~500 KW to several megawatts, has be... more Use of high-power solar arrays, at power levels ranging from ~500 KW to several megawatts, has been proposed for a solar-electric propulsion (SEP) demonstration mission, using a photovoltaic array to provide energy to a high-power xenon-fueled engine. One of the proposed applications of the high-power SEP technology is a mission to rendezvous with an asteroid and move it into lunar orbit for human exploration, the Asteroid Retrieval mission. The Solar Electric Propulsion project is dedicated to developing critical technologies to enable trips to further away destinations such as Mars or asteroids. NASA needs to reduce the cost of these ambitious exploration missions. High power and high efficiency SEP systems will require much less propellant to meet those requirements.
AbstractA study was conducted to determine the mass and power of an in situ propellant production... more AbstractA study was conducted to determine the mass and power of an in situ propellant production plant producing 10.5 t of liquid oxygen per year from the regolith at the lunar south pole. The car...
Introduction: Saturn's frigid moon Titan, visited by the Huygens probe in 2005, has a thick a... more Introduction: Saturn's frigid moon Titan, visited by the Huygens probe in 2005, has a thick atmosphere and three vast northern polar seas of methane and ethane : these seas are of particular interest for future exploration. These seas have a composition and conditions (1.5 bar, 92K) rather similar to those of Liquefied Natural Gas (LNG) on Earth. The largest, Kraken Mare, is 1000km in extent but of unknown depth: its complex shoreline morphology and evaporite deposits mapped by Cassini hint at a rich chemistry and climate history. We have developed a practical design for a robot submersible to explore this exotic environment, drawing on experience in terrestrial AUVs/UUVs as well as spacecraft systems. The proposed ~1-tonne vehicle, with a radioisotope Stirling generator power source, would be delivered to splashdown circa 2040, to make a ~90-day, ~2000km voyage of exploration around the perimeter, and across the central depths of, Kraken (Fig.1).
2018 AIAA SPACE and Astronautics Forum and Exposition, 2018
Mars. Two of the technologies under study that are considered to be the most near-term with respe... more Mars. Two of the technologies under study that are considered to be the most near-term with respect to technology readiness level (TRL) are traditional chemical propulsion systems and high-power Solar Electric Propulsion (SEP) systems. The benefit of relatively low trip times inherent in using impulsive chemical propulsion systems to perform the full round-trip DV for human Mars missions is hampered by the large propellant mass required to perform these burns. SEP systems offer the benefit of much lower propellant requirements to perform the same round-trip missions, at the cost of longer trip times. Traditionally, impulsive chemical systems are better suited than SEP when used in a gravity well, and SEP systems are more efficient than traditional impulsive systems when used in interplanetary space. A typical mission to Mars includes both of these scenarios, and thus several NASA architecture studies, performed over the last few years, have looked to combine the use of both SEP and chemical propulsion systems where they are the most beneficial to human Mars missions. This combined propulsion system concept has been referred to as a SEP/Chem hybrid Mars Transfer Vehicle and is currently shown as the concept Deep Space Transport (DST) in the March 2017 NASA presentation to the National Aerospace Council (NAC).
This paper presents a concept for a human mission to Mars orbit that features direct robotic expl... more This paper presents a concept for a human mission to Mars orbit that features direct robotic exploration of the planet’s surface via teleoperation from orbit. This mission is a good example of Human Exploration using Real-time Robotic Operations (HERRO), an exploration strategy that refrains from sending humans to the surfaces of planets with large gravity wells. HERRO avoids the need for complex and expensive man-rated lander/ascent vehicles and surface systems. Additionally, the humans are close enough to the surface to effectively eliminate the two-way communication latency that constrains typical robotic space missions, thus allowing real-time command and control of surface operations and experiments by the crew. Through use of state-of-the-art telecommunications and robotics, HERRO providesthe cognitive and decision-making advantages of having humans at the site of study for only a fraction of the cost of conventional human surface missions. It is very similar to how oceanograp...
There is considerable interest in expanding the applicability of cubesat spacecraft into lightwei... more There is considerable interest in expanding the applicability of cubesat spacecraft into lightweight, low cost missions beyond Low Earth Orbit. A conceptual design was done for a 6-U cubesat for a technology demonstration to demonstrate use of electric propulsion systems on a small satellite platform. The candidate objective was a mission to be launched on the SLS test launch EM-1 to visit a Near-Earth asteroid. Both asteroid fly-by and asteroid rendezvous missions were analyzed. Propulsion systems analyzed included cold-gas thruster systems, Hall and ion thrusters, incorporating either Xenon or Iodine propellant, and an electrospray thruster. The mission takes advantage of the ability of the SLS launch to place it into an initial trajectory of C3=0. Targeting asteroids that fly close to earth minimizes the propulsion required for fly-by/rendezvous. Due to mass constraints, high specific impulse is required, and volume constraints mean the propellant density was also of great importance to the ability to achieve the required ∆V. This improves the relative usefulness of the electrospray salt, with higher propellant density. In order to minimize high pressure tanks and volatiles, the salt electrospray and iodine ion propulsion systems were the optimum designs for the fly-by and rendezvous missions respectively combined with a thruster gimbal and wheel system For the candidate fly-by mission, with a mission ∆V of about 400 m/s, the mission objectives could be accomplished with a 800s electrospray propulsion system, incorporating a propellant-less cathode and a bellows salt tank. This propulsion system is planned for demonstration on 2015 LEO and 2016 GEO DARPA flights. For the rendezvous mission, at a ∆V of 2000 m/s, the mission could be accomplished with a 50W miniature ion propulsion system running iodine propellant. This propulsion system is not yet demonstrated in space. The conceptual design shows that an asteroid mission is possible using a cubesat platform with high-efficiency electric propulsion.
Global surface mobility is the key to comprehensive exploration of the diverse surfaces of worlds... more Global surface mobility is the key to comprehensive exploration of the diverse surfaces of worlds such as Triton. We propose to do this with a rocket-powered "hopper" vehicle • The Triton Hopper is a NASA Innovative Advanced Concepts (NIAC) project to design a mission to not merely land, but repeatedly fly across the surface of Triton, utilizing the volatile surface ices (primarily nitrogen) as propellant for a radioisotope-heated thermal rocket engine to launch across the surface and explore all the moon's varied terrain. • With a calculated range of 20 km per hop, equator-to-pole mobility can be achieved over a primary mission duration of 2 years. • The same concept of using in-situ ices to refuel a radioisotope engine for global mobility would be applicable to other airless bodies in the solar system. Using Nuclear Electric Propulsion for the transfer vehicle, the same concept can be applied for a mission to the surface of Pluto. The mission described would be either a flagship-class mission, or a component of a flagshipclass mission that also includes science investigations of Neptune and its smaller moons.
We present a preliminary design for a 3 kg expendable measurement system to descend to a depth of... more We present a preliminary design for a 3 kg expendable measurement system to descend to a depth of up to 1 km in the cryogenic hydrocarbon seas (Kraken and Ligeia Mare) of Saturn's moon Titan. These could profile the temperature and gross composition (methane/ethane) and providing information on the constitution of the seabed. Particular features of the Titan environment distinct from Earth are (1) the interior of this small vehicle must be thermally isolated from the 94 K liquid (2) 1 km depth on Titan entails overpressures of only 10 bar, and (3) that the low dielectric loss of the liquid allows data transmission by radio link. A surface vessel equipped with such expendable dropsondes could accomplish much of the science previously considered for submersible vehicles, while avoiding the challenges of buoyancy control.
Advances in solar array and electric thruster technologies now offer the promise of new, very cap... more Advances in solar array and electric thruster technologies now offer the promise of new, very capable space transportation systems that will allow us to cost effectively explore the solar system. NASA has developed numerous solar electric propulsion spacecraft concepts with power levels ranging from tens to hundreds of kilowatts for robotic and piloted missions to asteroids and Mars. This paper describes nine electric and hybrid solar electric/chemical propulsion concepts developed over the last 5 years and discusses how they might be used for human exploration of the inner solar system.
The Mars Geyser Hopper is a design concept for a Discovery-class spacecraft using Advanced Stirli... more The Mars Geyser Hopper is a design concept for a Discovery-class spacecraft using Advanced Stirling Radioisotope Generator (ASRG) power source, with the capability to make a rocket-powered "hop" to investigate regions of scientific interest.
A conceptual design was performed for a 6-U cubesat for a technology demonstration to be launched... more A conceptual design was performed for a 6-U cubesat for a technology demonstration to be launched on the NASA Space Launch System (SLS) test launch EM-1, to be launched into a free-return translunar trajectory. The mission purpose was to demonstrate use of electric propulsion systems on a small satellite platform. The candidate objective chosen was a mission to visit a Near-Earth asteroid. Both asteroid fly-by and asteroid rendezvous missions were analyzed. Propulsion systems analyzed included cold-gas thruster systems, Hall and ion thrusters, incorporating either Xenon or Iodine propellant, and an electrospray thruster. The mission takes advantage of the ability of the SLS launch to place it into an initial trajectory of C3=0.
The Triton Hopper is a NASA Innovative Advanced Concepts (NIAC) project to design a mission to no... more The Triton Hopper is a NASA Innovative Advanced Concepts (NIAC) project to design a mission to not merely land, but repeatedly fly across the surface of Triton, utilizing the volatile surface ices (primarily nitrogen) as propellant for a radioisotope-heated thermal rocket engine to launch across the surface and explore all the moon’s varied terrain. An engineering design study of the vehicle and mission was done. With a calculated range of 20 km per hop, equator-to-pole mobility can be achieved over a primary mission duration of 2 years. Using Nuclear Electric Propulsion for the transfer vehicle, the same concept can be applied for a mission to the surface of Pluto.
The Lunar Communications Terminal (LCT) COllaborative Modeling and Parametric Assessment of Space... more The Lunar Communications Terminal (LCT) COllaborative Modeling and Parametric Assessment of Space Systems (COMPASS) session designed a terminal to provide communications between lunar South Pole assets, communications relay to/from these assets through an orbiting Lunar Relay Satellite (LRS) and navigation support. The design included a complete master equipment list, power requirement list, configuration design, and brief risk assessment and cost analysis. The Terminal consists of a pallet containing the communications and avionics equipment, surrounded by the thermal control system (radiator), an attached, deployable 10-m tower, upon which were mounted locally broadcasting and receiving modems and a deployable 1 m diameter Ka/S band dish which provides relay communications with the lunar relay satellites and, as a backup, Earth when it is in view. All power was assumed to come from the lunar outpost Habitat. Three LCT design options were explored: a stand-alone LCT servicing the m...
Use of high-power solar arrays, at power levels ranging from ~500 KW to several megawatts, has be... more Use of high-power solar arrays, at power levels ranging from ~500 KW to several megawatts, has been proposed for a solar-electric propulsion (SEP) demonstration mission, using a photovoltaic array to provide energy to a high-power xenon-fueled engine. One of the proposed applications of the high-power SEP technology is a mission to rendezvous with an asteroid and move it into lunar orbit for human exploration, the Asteroid Retrieval mission. The Solar Electric Propulsion project is dedicated to developing critical technologies to enable trips to further away destinations such as Mars or asteroids. NASA needs to reduce the cost of these ambitious exploration missions. High power and high efficiency SEP systems will require much less propellant to meet those requirements.
AbstractA study was conducted to determine the mass and power of an in situ propellant production... more AbstractA study was conducted to determine the mass and power of an in situ propellant production plant producing 10.5 t of liquid oxygen per year from the regolith at the lunar south pole. The car...
Introduction: Saturn's frigid moon Titan, visited by the Huygens probe in 2005, has a thick a... more Introduction: Saturn's frigid moon Titan, visited by the Huygens probe in 2005, has a thick atmosphere and three vast northern polar seas of methane and ethane : these seas are of particular interest for future exploration. These seas have a composition and conditions (1.5 bar, 92K) rather similar to those of Liquefied Natural Gas (LNG) on Earth. The largest, Kraken Mare, is 1000km in extent but of unknown depth: its complex shoreline morphology and evaporite deposits mapped by Cassini hint at a rich chemistry and climate history. We have developed a practical design for a robot submersible to explore this exotic environment, drawing on experience in terrestrial AUVs/UUVs as well as spacecraft systems. The proposed ~1-tonne vehicle, with a radioisotope Stirling generator power source, would be delivered to splashdown circa 2040, to make a ~90-day, ~2000km voyage of exploration around the perimeter, and across the central depths of, Kraken (Fig.1).
2018 AIAA SPACE and Astronautics Forum and Exposition, 2018
Mars. Two of the technologies under study that are considered to be the most near-term with respe... more Mars. Two of the technologies under study that are considered to be the most near-term with respect to technology readiness level (TRL) are traditional chemical propulsion systems and high-power Solar Electric Propulsion (SEP) systems. The benefit of relatively low trip times inherent in using impulsive chemical propulsion systems to perform the full round-trip DV for human Mars missions is hampered by the large propellant mass required to perform these burns. SEP systems offer the benefit of much lower propellant requirements to perform the same round-trip missions, at the cost of longer trip times. Traditionally, impulsive chemical systems are better suited than SEP when used in a gravity well, and SEP systems are more efficient than traditional impulsive systems when used in interplanetary space. A typical mission to Mars includes both of these scenarios, and thus several NASA architecture studies, performed over the last few years, have looked to combine the use of both SEP and chemical propulsion systems where they are the most beneficial to human Mars missions. This combined propulsion system concept has been referred to as a SEP/Chem hybrid Mars Transfer Vehicle and is currently shown as the concept Deep Space Transport (DST) in the March 2017 NASA presentation to the National Aerospace Council (NAC).
This paper presents a concept for a human mission to Mars orbit that features direct robotic expl... more This paper presents a concept for a human mission to Mars orbit that features direct robotic exploration of the planet’s surface via teleoperation from orbit. This mission is a good example of Human Exploration using Real-time Robotic Operations (HERRO), an exploration strategy that refrains from sending humans to the surfaces of planets with large gravity wells. HERRO avoids the need for complex and expensive man-rated lander/ascent vehicles and surface systems. Additionally, the humans are close enough to the surface to effectively eliminate the two-way communication latency that constrains typical robotic space missions, thus allowing real-time command and control of surface operations and experiments by the crew. Through use of state-of-the-art telecommunications and robotics, HERRO providesthe cognitive and decision-making advantages of having humans at the site of study for only a fraction of the cost of conventional human surface missions. It is very similar to how oceanograp...
There is considerable interest in expanding the applicability of cubesat spacecraft into lightwei... more There is considerable interest in expanding the applicability of cubesat spacecraft into lightweight, low cost missions beyond Low Earth Orbit. A conceptual design was done for a 6-U cubesat for a technology demonstration to demonstrate use of electric propulsion systems on a small satellite platform. The candidate objective was a mission to be launched on the SLS test launch EM-1 to visit a Near-Earth asteroid. Both asteroid fly-by and asteroid rendezvous missions were analyzed. Propulsion systems analyzed included cold-gas thruster systems, Hall and ion thrusters, incorporating either Xenon or Iodine propellant, and an electrospray thruster. The mission takes advantage of the ability of the SLS launch to place it into an initial trajectory of C3=0. Targeting asteroids that fly close to earth minimizes the propulsion required for fly-by/rendezvous. Due to mass constraints, high specific impulse is required, and volume constraints mean the propellant density was also of great importance to the ability to achieve the required ∆V. This improves the relative usefulness of the electrospray salt, with higher propellant density. In order to minimize high pressure tanks and volatiles, the salt electrospray and iodine ion propulsion systems were the optimum designs for the fly-by and rendezvous missions respectively combined with a thruster gimbal and wheel system For the candidate fly-by mission, with a mission ∆V of about 400 m/s, the mission objectives could be accomplished with a 800s electrospray propulsion system, incorporating a propellant-less cathode and a bellows salt tank. This propulsion system is planned for demonstration on 2015 LEO and 2016 GEO DARPA flights. For the rendezvous mission, at a ∆V of 2000 m/s, the mission could be accomplished with a 50W miniature ion propulsion system running iodine propellant. This propulsion system is not yet demonstrated in space. The conceptual design shows that an asteroid mission is possible using a cubesat platform with high-efficiency electric propulsion.
Global surface mobility is the key to comprehensive exploration of the diverse surfaces of worlds... more Global surface mobility is the key to comprehensive exploration of the diverse surfaces of worlds such as Triton. We propose to do this with a rocket-powered "hopper" vehicle • The Triton Hopper is a NASA Innovative Advanced Concepts (NIAC) project to design a mission to not merely land, but repeatedly fly across the surface of Triton, utilizing the volatile surface ices (primarily nitrogen) as propellant for a radioisotope-heated thermal rocket engine to launch across the surface and explore all the moon's varied terrain. • With a calculated range of 20 km per hop, equator-to-pole mobility can be achieved over a primary mission duration of 2 years. • The same concept of using in-situ ices to refuel a radioisotope engine for global mobility would be applicable to other airless bodies in the solar system. Using Nuclear Electric Propulsion for the transfer vehicle, the same concept can be applied for a mission to the surface of Pluto. The mission described would be either a flagship-class mission, or a component of a flagshipclass mission that also includes science investigations of Neptune and its smaller moons.
We present a preliminary design for a 3 kg expendable measurement system to descend to a depth of... more We present a preliminary design for a 3 kg expendable measurement system to descend to a depth of up to 1 km in the cryogenic hydrocarbon seas (Kraken and Ligeia Mare) of Saturn's moon Titan. These could profile the temperature and gross composition (methane/ethane) and providing information on the constitution of the seabed. Particular features of the Titan environment distinct from Earth are (1) the interior of this small vehicle must be thermally isolated from the 94 K liquid (2) 1 km depth on Titan entails overpressures of only 10 bar, and (3) that the low dielectric loss of the liquid allows data transmission by radio link. A surface vessel equipped with such expendable dropsondes could accomplish much of the science previously considered for submersible vehicles, while avoiding the challenges of buoyancy control.
Advances in solar array and electric thruster technologies now offer the promise of new, very cap... more Advances in solar array and electric thruster technologies now offer the promise of new, very capable space transportation systems that will allow us to cost effectively explore the solar system. NASA has developed numerous solar electric propulsion spacecraft concepts with power levels ranging from tens to hundreds of kilowatts for robotic and piloted missions to asteroids and Mars. This paper describes nine electric and hybrid solar electric/chemical propulsion concepts developed over the last 5 years and discusses how they might be used for human exploration of the inner solar system.
The Mars Geyser Hopper is a design concept for a Discovery-class spacecraft using Advanced Stirli... more The Mars Geyser Hopper is a design concept for a Discovery-class spacecraft using Advanced Stirling Radioisotope Generator (ASRG) power source, with the capability to make a rocket-powered "hop" to investigate regions of scientific interest.
A conceptual design was performed for a 6-U cubesat for a technology demonstration to be launched... more A conceptual design was performed for a 6-U cubesat for a technology demonstration to be launched on the NASA Space Launch System (SLS) test launch EM-1, to be launched into a free-return translunar trajectory. The mission purpose was to demonstrate use of electric propulsion systems on a small satellite platform. The candidate objective chosen was a mission to visit a Near-Earth asteroid. Both asteroid fly-by and asteroid rendezvous missions were analyzed. Propulsion systems analyzed included cold-gas thruster systems, Hall and ion thrusters, incorporating either Xenon or Iodine propellant, and an electrospray thruster. The mission takes advantage of the ability of the SLS launch to place it into an initial trajectory of C3=0.
The Triton Hopper is a NASA Innovative Advanced Concepts (NIAC) project to design a mission to no... more The Triton Hopper is a NASA Innovative Advanced Concepts (NIAC) project to design a mission to not merely land, but repeatedly fly across the surface of Triton, utilizing the volatile surface ices (primarily nitrogen) as propellant for a radioisotope-heated thermal rocket engine to launch across the surface and explore all the moon’s varied terrain. An engineering design study of the vehicle and mission was done. With a calculated range of 20 km per hop, equator-to-pole mobility can be achieved over a primary mission duration of 2 years. Using Nuclear Electric Propulsion for the transfer vehicle, the same concept can be applied for a mission to the surface of Pluto.
The Lunar Communications Terminal (LCT) COllaborative Modeling and Parametric Assessment of Space... more The Lunar Communications Terminal (LCT) COllaborative Modeling and Parametric Assessment of Space Systems (COMPASS) session designed a terminal to provide communications between lunar South Pole assets, communications relay to/from these assets through an orbiting Lunar Relay Satellite (LRS) and navigation support. The design included a complete master equipment list, power requirement list, configuration design, and brief risk assessment and cost analysis. The Terminal consists of a pallet containing the communications and avionics equipment, surrounded by the thermal control system (radiator), an attached, deployable 10-m tower, upon which were mounted locally broadcasting and receiving modems and a deployable 1 m diameter Ka/S band dish which provides relay communications with the lunar relay satellites and, as a backup, Earth when it is in view. All power was assumed to come from the lunar outpost Habitat. Three LCT design options were explored: a stand-alone LCT servicing the m...
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Papers by Steven Oleson