ScienceCraft for Outer Planet Exploration (SCOPE)

ScienceCraft for Outer Planet Exploration (SCOPE)

2 min read

Preparations for Next Moonwalk Simulations Underway (and Underwater)

Artist’s depiction of ScienceCraft, which integrates the science instrument with the spacecraft by printing a quantum dot spectrometer directly on the solar sail to form a monolithic, lightweight structure
Artist’s depiction of ScienceCraft, which integrates the science instrument with the spacecraft by printing a quantum dot spectrometer directly on the solar sail to form a monolithic, lightweight structure.
Mahmooda Sultana

Mahmooda Sultana
NASA Goddard Space Flight Center

Missions to the outer solar system are an important part of NASA’s goals because these scarcely visited worlds, particularly the ice giants Neptune and Uranus, hold secrets about the formation and evolution of our solar system and countless others. However, due to the high cost, long travel time and narrow window for mission implementation, outer solar system exploration has been extremely limited in more than 60 years of space exploration. In this NIAC, we are developing a mission architecture that addresses all of these challenges by using a ScienceCraft and enables science missions at the outer planet system. Sciencraft integrates a science instrument and spacecraft into one monolithic and lightweight structure. By printing an ultra-lightweight quantum dot-based spectrometer, developed by the PI Sultana, directly on the solar sail we create a breakthrough spacecraft architecture allowing an unprecedented parallelism and throughput of data collection, and rapid travel across the solar system. Unlike conventional solar sails that serve only to propel small cubesats, ScienceCraft puts its area at use for spectroscopy, pushing the boundary of scientific exploration of the outer solar system. ScienceCraft offers an attractive low resource platform that can enable

science missions at a significantly lower cost and provide a large number of launch opportunities as a secondary payload. By leveraging these benefits, we propose a mission concept to Triton, a unique planetary body in our solar system, within the short window that closes around 2045 to answer compelling science questions about Triton’s atmosphere, ionosphere, plumes and internal structure. In Phase I, we performed an end-to-end feasibility study for a Neptune-Triton mission using a ScienceCraft, as well as identifying the key technologies needed for such a mission and tall poles that we need to address. As part of phase II, we plan to further mature the mission concept, develop and demonstrate some of the key technologies, address the tall poles identified in phase I and develop a roadmap for implementing SCOPE.

2024 Phase I Selection

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Loura Hall

Flexible Levitation on a Track (FLOAT)

Flexible Levitation on a Track (FLOAT)

3 min read

Preparations for Next Moonwalk Simulations Underway (and Underwater)

Astronaut working on levitation track on lunar surface with Earth in distant sky.
Artist concept of novel approach proposed by a 2024 NIAC Phase II awardee for possible future missions depicting lunar surface with planet Earth on the horizon.
Credit: Ethan Schaler

Ethan Schaler
NASA Jet Propulsion Laboratory

We want to build the first lunar railway system, which will provide reliable, autonomous, and efficient payload transport on the Moon. A durable, long-life robotic transport system will be critical to the daily operations of a sustainable lunar base in the 2030’s, as envisioned in NASA’s Moon to Mars plan and mission concepts like the Robotic Lunar Surface Operations 2 (RLSO2), to:

— Transport regolith mined for ISRU consumables (H2O, LOX, LH2) or construction

— Transport payloads around the lunar base and to / from landing zones or other outposts

We propose developing FLOAT — Flexible Levitation on a Track — to meet these transportation needs.

The FLOAT system employs unpowered magnetic robots that levitate over a 3-layer flexible film track: a graphite layer enables robots to passively float over tracks using diamagnetic levitation, a flex-circuit layer generates electromagnetic thrust to controllably propel

robots along tracks, and an optional thin-film solar panel layer generates power for the base when in sunlight. FLOAT robots have no moving parts and levitate over the track to minimize lunar dust abrasion / wear, unlike lunar robots with wheels, legs, or tracks.

FLOAT tracks unroll directly onto the lunar regolith to avoid major on-site construction — unlike conventional roads, railways, or cableways. Individual FLOAT robots will be able to transport payloads of varying shape / size (>30 kg/m^2) at useful speeds (>0.5m/s), and a large-scale FLOAT system will be capable of moving up to 100,000s kg of regolith / payload multiple kilometers per day. FLOAT will operate autonomously in the dusty, inhospitable lunar environment with minimal site preparation, and its network of tracks can be rolled-up / reconfigured over time to match evolving lunar base mission requirements.

In Phase 2, we will continue to retire risks related to the manufacture, deployment, control, and long-term operation of meter-scale robots / km-scale tracks that support human exploration (HEO) activities on the Moon, by accomplishing the following key tasks:

— Design, manufacture, and test a series of sub-scale robot / track prototypes, culminating with a demonstration in a lunar-analog testbed (that includes testing various site preparation and track deployment strategies)

— Investigate impacts of environmental effects (e.g. temperature, radiation, charging, lunar regolith simulant contamination, etc.) on system performance and longevity

— Investigate / define a technology roadmap to address technology gaps and mature manufacturing capability for critical hardware (e.g. large-area magnetic arrays with mm-scale magnetic domains, and large-area flex-circuit boards)

— Continue refining simulations of FLOAT system designs with increased fidelity, to provide improved performance estimates under the RLSO2 mission concept We will also leverage these sub-scale prototypes to explore opportunities for follow-on technology demonstrations on sub-orbital flights (via Flight Opportunities / TechFlights) or lunar technology demos (via LSII / CLPS landers)

2024 Phase I Selection

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Loura Hall

Radioisotope Thermoradiative Cell Power Generator

Radioisotope Thermoradiative Cell Power Generator

3 min read

Preparations for Next Moonwalk Simulations Underway (and Underwater)

Artist’s depiction of Radioisotope Thermoradiative Cell Power Generator
Artist’s depiction of Radioisotope Thermoradiative Cell Power Generator
Stephen Polly

Stephen Polly
Rochester Institute of Technology

In this project we will continue our Phase I efforts to develop and demonstrate the feasibility of a revolutionary power source for missions to the outer planets utilizing a new paradigm in thermal power conversion, the thermoradiative cell (TRC). Operating like a solar cell in reverse, the TRC converts heat from a radioisotope source into infrared light which is sent off into the cold universe. In this process, electricity is generated. In our Phase I study, we showed 8 W of electrical power is possible from the 62.5 W Pu-238 pellet from a general purpose heat source using a 0.28 eV bandgap TRC operating at 600 K. The necessary array includes 1,125 cm² of TRC emitters, or just over 50% of the surface area of a 6U cubesat. With a mass (heat source + TRC) of 622 g, a mass specific power of 12.7 W/kg is possible, over a 4.5x improvement from heritage multi-mission radioisotope thermoelectric generator (MMRTG) was shown. Building on our results from Phase I, we believe there is much more potential to unlock here.

Using low-bandgap III-V materials such as InAsSb in nanostructured arrays to limit potential loss mechanisms, a 25x improvement in mass specific power and a four order of magnitude decrease in volume from a MMRTG is an early estimate, with higher performance possible depending on operating conditions. TRC technology will allow a proliferation of small versatile spacecraft with power requirements not met by photovoltaic arrays or bulky, inefficient MMRTG systems. This will directly enable small-sat missions to the outer planets as well as operations in permanent shadow such as polar lunar craters.

This study will investigate the thermodynamics and feasibility of the development of a radioisotope enabled thermoradiative power source focusing on system size, weight, power (SWaP) while continuing to integrate the effects of potential power and efficiency loss mechanisms developed in Phase I. Experimentally, materials and TRC devices will be grown including InAsSb-based type-II superlattices by metalorganic vapor phase epitaxy (MOVPE) to target low-bandgap materials with suppressed Auger recombination. Metal-semiconductor contacts capable of surviving the required elevated temperatures will be investigated. TRC devices will be tested for performance at elevated temperature facing a cold ambient under vacuum in a modified cryostat testing apparatus developed in Phase I.

We will analyze a radioisotope thermoradiative converter to power a cubesat mission operating at Uranus. This will include an engineering design study of our reference mission with the Compass engineering team at NASA Glenn Research Center with expertise on the impact of new technologies on spacecraft design in the context of an overall mission, incorporating all engineering disciplines and combining them at a system level. Finally, we will develop a technological roadmap for the necessary components of the TRC to power a future mission.

2024 Phase I Selection

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Loura Hall

The Great Observatory for Long Wavelengths (GO-LoW)

The Great Observatory for Long Wavelengths (GO-LoW)

3 min read

Preparations for Next Moonwalk Simulations Underway (and Underwater)

Artist’s depiction of The Great Observatory for Long Wavelengths (GO-LoW)
Artist’s depiction of The Great Observatory for Long Wavelengths (GO-LoW)
Mary Knapp

Mary Knapp
MIT

Humankind has never before seen the low frequency radio sky. It is hidden from ground-based telescopes by the Earth’s ionosphere and challenging to access from space with traditional missions because the long wavelengths involved (meter- to kilometer-scale)

require infeasibly massive telescopes to see clearly. Electromagnetic radiation at these low frequencies carries crucial information about exoplanetary and stellar magnetic fields (a key ingredient to habitability), the interstellar/intergalactic medium, and the earliest

stars and galaxies.

The Great Observatory for Long Wavelengths (GO-LoW) proposes an interferometric array of thousands of identical SmallSats at an Earth-Sun Lagrange point (e.g. L5) to measure the magnetic fields of terrestrial exoplanets via detections of their radio emissions at

frequencies between 100 kHz and 15 MHz. Each spacecraft will carry an innovative Vector Sensor Antenna, which will enable the first survey of exoplanetary magnetic fields within 5 parsecs.

In a departure from the traditional approach of a single large and expensive spacecraft (i.e. HST, Chandra, JWST) with many single points of failure, we propose an interferometric Great Observatory comprised of thousands of small, cheap, and easily-replaceable

nodes. Interferometry, a technique that combines signals from many spatially separated receivers to form a large ‘virtual’ telescope, is ideally suited to long wavelength astronomy. The individual antenna/receiver systems are simple, no large structures are required, and the very large spacing between nodes provides high spatial resolution.

In our Phase I study, we found that a hybrid constellation architecture was most efficient. Small and simple “listener” nodes (LNs) collect raw radio data using a deployable vector sensor antenna. A small number of larger, more capable “communication and computation” nodes (CCNs) collect data from LNs via a local radio network, perform beamforming processing to reduce the data volume, and then transmit the data to Earth via free space optics (lasercomm). Cross correlation of the beamformed data is performed on Earth, where computational resources are not tightly constrained. The CCNs are also responsible for constellation management, including timing distribution and ranging. The Phase I study also showed that the LN-CCN architecture optimizes packing efficiency, allowing a small number of super-heavy lift launch vehicles (e.g. Starship) to deploy the entire constellation to L4.

The Phase I study showed that the key innovation for GO-LoW is the “system of systems.” The technology needed for each individual piece of the observatory (e.g. lasercomm, CubeSats, ranging, timing, data transfer, data processing, orbit propagation) is not a big leap from current state of the art, but the coordination of all these physical elements, data products, and communications systems is novel and challenging, especially at scale.

In the proposed study, we will (1) develop a real-time, multi-agent simulation of the GO-LoW constellation that demonstrates the autonomous operations architecture required to achieve a

large (up to 100k) constellation outside of Earth’s orbit, (2) continue to refine the science case and requirements by simulating science output from the constellation and assessing major error sources informed by the real-time simulation, (3) develop appropriate orbital modeling to assess propulsion requirements for stationkeeping at a stable Lagrange point, and (4) further refine the technology roadmap required to make GO-LoW feasible in the next 10-20 years. GO-LoW represents a disruptive new paradigm for space missions. It achieves reliability through massive redundancy rather than extensive testing. It can evolve and grow with new technology rather than being bound to a fixed point in hardware/software development. Finally, it promises to open a new spectral window on the universe where unforeseen discoveries surely await.

2024 Phase I Selection

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Loura Hall

Pulsed Plasma Rocket (PPR): Shielded, Fast Transits for Humans to Mars

Pulsed Plasma Rocket (PPR): Shielded, Fast Transits for Humans to Mars

2 min read

Preparations for Next Moonwalk Simulations Underway (and Underwater)

Labeled simplified diagram of the PPR system.
Simplified image of the PPR system.
Brianna Clements

Brianna Clements
Howe Industries

The future of a space-faring civilization will depend on the ability to move both cargo and humans efficiently and rapidly. Due to the extremely large distances that are involved in space travel, the spacecraft must reach high velocities for reasonable mission transit times. Thus, a propulsion system that produces a high thrust with a high specific impulse is essential. However, no such technologies are currently available.

Howe Industries is currently developing a propulsion system that may generate up to 100,000 N of thrust with a specific impulse (Isp) of 5,000 seconds. The Pulsed Plasma Rocket (PPR) is originally derived from the Pulsed Fission Fusion concept, but is smaller, simpler, and more affordable. The exceptional performance of the PPR, combining high Isp and high thrust, holds the potential to revolutionize space exploration. The system’s high efficiency allows for manned missions to Mars to be completed within a mere two months. Alternatively, the PPR enables the transport of much heavier spacecraft that are equipped with shielding against Galactic Cosmic Rays, thereby reducing crew exposure to negligible levels. The system can also be used for other far range missions, such as those to the Asteroid Belt or even to the 550 AU location, where the Sun’s gravitational lens focuses can be considered. The PPR enables a whole new era in space exploration.

The NIAC Phase I study focused on a large, heavily shielded ship to transport humans and cargo to Mars for the development of a Martian base. The main topics included: assessing the neutronics of the system, designing the spacecraft, power system, and necessary subsystems, analyzing the magnetic nozzle capabilities, and determining trajectories and benefits of the PPR. Phase II will build upon these assessments and further the PPR concept.

In Phase II, we plan to:

  1. Optimize the engine design for reduced mass and higher Isp
  2. Perform proof-of-concept experiments of major components
  3. Complete a ship design for shielded human missions to Mars

2024 Phase I Selection

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Loura Hall