Tethers Unlimited Aims to Put SPIDERs on Mars

by Douglas Messier
Managing Editor

During the 1970’s, David Bowie sang about Ziggy Stardust and the spiders from Mars. If Tethers Unlimited has its way, the Red Planet will be crawling with them.

Earlier this month, NASA selected the Bothell, Washington-based company for a small business award to work on its Sensing and Positioning in Deep Environments with Retrieval (SPIDER) surface exploration system.

“The SPIDER concept is an innovative exploration architecture that shatters the mold of traditional wheeled, legged, or propulsive hopper vehicles,” the company said in its proposal summary. “Instead, SPIDER utilizes launchable tethered anchors and on-board winches to perform landing, mobility, and sampling operations while suspended over the crater of interest.

“The concept is akin to the ‘skycams’ used in sports arenas, and it eliminates several major concerns with ground-based rovers, including: 1) entrapment, 2) overturning, 3) contamination of the sample site, and 4) lunar dust in the mechanisms,” the summary added.

Tethers Unlimited said the SPIDER technologies could be customized for the exploration of the moon, Mars, Venus and Titan. They could also be used to assist astronauts as they walk on other planetary surfaces.

SPIDER was one of four Tethers Unlimited proposals that NASA selected for funding under its Small Business Innovation Research (SBIR) Phase 1 program. The awards are worth up to $125,000 apiece for six months.

NASA also selected a proposal from Tethers Unlimited and Western Washington University for funding under the Small Business Technology Transfer (STTR) Phase I program. That award is worth a maximum of $125,000 over 13 months.

The company’s HyperBus Cargo Platform is focused on moving modules around in space to support orbital construction. The goal is “to create a palletized system that is capable of supporting transport, emplacement, and exchange of sub-modules in the 1-100 kg range,” the proposal summary stated.

The HyperBus would enable the “transport, emplacement, servicing, and exchange of sub-modules on persistent platforms assembled in-space,” the company said. “It will provide a cost-effective means for utilizing secondary payload launches and ISS deployment to support construction and operation persistent platforms for Earth science, space astronomy, and manned exploration.”

NASA also selected Tethers Unlimited’s androgynous robotic tool-change interface (ARTIE) for a SBIR award. ARTIE is designed for the hard and soft capture of tools and infrastructure support for robotic assets such as Tethers Unlimited’s KRAKEN robotic manipulator and NASA’s Astrobee.

“The ARTIE interface will provide tool-change functionality for robotic systems supporting astronaut activities and autonomous operations on the ISS and the Deep Space Gateway, on platforms such as AstroBee and the MANTIS teleoperation system,” the project summary stated. “It will also support robotic manipulator functionalities for in-Space Assembly activities such as construction of the 30 m iSAT Space Telescope.”

Tethers Unlimited’s SBIR awards are not just limited to the moon, Mars and Earth orbit.

“The Venus or Titan EXploration (VORTEX) gimbal is a low Size, Weight, and Power, high performance pointing mechanism capable of supporting future aerobot exploration missions as well as other missions with extreme environments,” according to the proposal summary.

“The VORTEX gimbal will support future NASA aerobot exploration missions to Venus and other planetary bodies by providing a reliable, lightweight, mechanism for pointing and articulation of high gain antennas,” the proposal added. “VORTEX is well suited for missions with instruments that require precision pointing and articulation with data or power throughput, such as optical and high-frequency RF satellite crosslinks.”

For the STTR award, Tethers Unlimited partnered with Western Washington University to use additive manufacturing to develop an improved thermal protection system for spacecraft. The company said the Resin Additive Manufacturing Processed Thermal Protection Systems (RAMP TPS) would be cheaper and easier to produce as well as stronger than existing systems.

“RAMP TPS technology will enable cost-effective production of advanced thermal protection shields for a range of re-entry applications, including lunar exploration missions, Mars sampling missions, and asteroid sampling missions such as OSIRIS-Rex,” the company said.

“RAMP TPS could enable rapid, cost-effective production of thermal protection shields for ICBM re-entry bodies. It will also enable in-space production of large aerobrakes to support commercial ventures to obtain lunar resources such as water from the lunar poles and deliver it to propellant depots in LEO using aerobraking techniques,” Tethers Unlimited added.

Summaries of Tethers Unlimited’s small business awards follow.

SBIRs

Sensing and Positioning in Deep Environments with Retrieval (SPIDER)
Subtopic Title: Lunar Rover Technologies for In-situ Resource Utilization and Exploration

Tethers Unlimited, Inc.
Bothell, WA

Principal Investigator
Gregory Jimmerson

Estimated Technology Readiness Level (TRL) :
Begin: 2
End: 4

Technical Abstract

To enable future Lunar ISRU missions to more effectively explore, sample, and excavate within the permanently shaded polar craters, Tethers Unlimited Inc. (TUI) proposes to develop the Sensing and Positioning In Deep Environments with Retrieval (SPIDER) System.

The SPIDER concept is an innovative exploration architecture that shatters the mold of traditional wheeled, legged, or propulsive hopper vehicles. Instead, SPIDER utilizes launchable tethered anchors and on-board winches to perform landing, mobility, and sampling operations while suspended over the crater of interest.

The concept is akin to the “skycams” used in sports arenas, and it eliminates several major concerns with ground-based rovers, including: 1) entrapment, 2) overturning, 3) contamination of the sample site, and 4) lunar dust in the mechanisms.

In the Phase I effort, TUI will perform concept development, design, and engineering of the launchable tethered anchoring system and accompanying winch sized for a specific lunar crater and to accommodate an ISRU payload to be agreed upon with the sponsor.

At the end of the Phase I the SPIDER technology will be at TRL 4. Prototyping and testing of the integrated system will be performed in the Phase II effort, establishing the design at TRL 6.

Potential NASA Applications

The SPIDER System directly addresses NASA 2015 Space Technology Roadmap TA4.2.1 for Extreme Terrain Mobility, TA4.2.3 for Above Surface Mobility, TA 4.2.8 for Mobility Components, and TA7.1.2 for In-Situ Resource Utilization. The SPIDER technologies can be customized to enable greater mobility for Lunar Exploration, Mars Rovers, Venus and Titan aerobots, and Astronaut EVAs on planetary surfaces.

Potential Non-NASA Applications

SPIDER systems can support resource exploration and development by ventures such as Blue Origin, Astrobotic, Moon Express, Lockheed Martin, and Boeing. The SPIDER concepts could enable wrangling of asteroids or excavating resources from Martian valleys and cliff faces. Terrestrial applications include launchable anchoring systems for the DoD, FEMA, and Search and Rescue organizations.

Duration: 6 months


HyperBus Cargo Platform
Subtopic Title: In-Space Sub-Modular Assembly

Tethers Unlimited, Inc.
Bothell, WA

Principal Investigator
Dr. Daniel Reuster

Estimated Technology Readiness Level (TRL) :
Begin: 2
End: 3

Technical Abstract

NASA has identified the need for a palletizing system to support transport, emplacement and exchange of sub-modules in the 1-100 kg range. This need correlates to NASA’s Technology Roadmaps in the publication entitled, “Space Assembly of Large Structural System Architecture (SALSSA)”.

In support of this need, Tethers Unlimited, Inc. (TUI) proposes to leverage its HyperBus “Space as a Service” platform to create a palletized system that is capable of supporting transport, emplacement, and exchange of sub-modules in the 1-100 kg range.

The HyperBus Cargo will utilize a “double decker” configuration of TUI’s HyperBus platform in conjunction with NanoRacks’ KABER (24U) ISS and ENRCSD (36U) Cygnus satellite deployers to create a low cost, rapid deployment palletizing cargo transportation system, which will set a new standard for customer experience in the small satellite industry.

During the HyperBus Cargo program effort (Phase I and II), TUI personnel will evaluate multiple Concepts of Operations (ConOps) for the Cargo system, identify a complete set of requirements, develop a concept design, fabricate a prototype, and demonstrate the Cargo system in TUI’s robotics laboratory.

Potential NASA Applications

The HyperBus Cargo Platform supports NASA’s Space Assembly of Large Structural System Architectures (SALSSA) architecture, by enabling transport, emplacement, servicing, and exchange of sub-modules on persistent platforms assembled in-space. It will provide a cost-effective means for utilizing secondary payload launches and ISS deployment to support construction and operation persistent platforms for Earth science, space astronomy, and manned exploration.

Potential Non-NASA Applications

The HyperBus Cargo Platform will support construction and operation of persistent space platforms such as the AF/SMC Advanced Space Testbed (XST) and TUI’s Constructable LEO Platform by providing a cost-effective means to deliver modules and payloads to the platforms via secondary payload launches, and by facilitating integration of these modules onto the platforms.

Duration: 6 months


Versatile Hot-Swappable Robotic Interface
Subtopic Title: Technologies for Intra-Vehicular Activity Robotics

Tethers Unlimited, Inc.
Bothell, WA

Principal Investigator
Dr. Nathan Britton

Estimated Technology Readiness Level (TRL) :
Begin: 2
End: 4

Technical Abstract

Tethers Unlimited, Inc. (TUI) proposes to develop the “ARTIE”, an androgynous robotic tool-change interface for hard and soft capture of tools and infrastructure support for robotic assets on the Lunar Orbital Platform-Gateway.

ARTIE serves as a miniaturized power and data grapple interface for use on robotic assets, such as TUI’s KRAKEN robotic manipulator and NASA’s Astrobee. A Gateway version of Astrobee and KRAKEN can share tools and payloads with other assets for more efficient use of Gateway resources.

The androgynous nature of ARTIE will allow the same interface to be used throughout the Gateway as an infrastructural element. ARTIE can also serve Astrobee docking, support of a Gateway KRAKEN for base mounting and inch-worming, and dynamic reconfigurability of all Gateway robotic assets. The low-profile nature of ARTIE also reduces the cost and overhead of including soft-capture fixtures on payloads tools and infrastructural elements where autonomous support is anticipated.

In the Phase I effort, a proof of concept mechanism will be built and demonstrated to establish the feasibility of a small form-factor androgynous hard and soft capture connector, maturing the TRL to 4. In Phase II, the design will be implemented as an Astrobee payload for functional testing on the ISS.

Potential NASA Applications

The ARTIE interface will provide tool-change functionality for robotic systems supporting astronaut activities and autonomous operations on the ISS and the Deep Space Gateway, on platforms such as AstroBee and the MANTIS teleoperation system. It will also support robotic manipulator functionalities for in-Space Assembly activities such as construction of the 30 m iSAT Space Telescope.

Potential Non-NASA Applications

The ARTIE interface will enable TUI”s KRAKEN robotic arm to perform multiple functions in robotic assembly and in-space manufacturing systems such as the LEO Knight smallsat servicing vehicle, the OrbWeaver payload, and the AF/SMC Advanced Space Testbed (XST) Platform.

Duration: 6 months


Gimbal Mechanism for Extreme Environments
Subtopic Title: Extreme Environments Technology

Tethers Unlimited, Inc.
Bothell, WA

Principal Investigator
Jory St. Luise

Estimated Technology Readiness Level (TRL) :
Begin: 4
End: 5

Technical Abstract

The Venus or Titan EXploration (VORTEX) gimbal is a low Size, Weight, and Power, high performance pointing mechanism capable of supporting future aerobot exploration missions as well as other missions with extreme environments.

Scaled from Tethers Unlimited Inc.’s (TUI’s) existing COBRA carpal-wrist gimbal, the VORTEX gimbal provides continuous full hemispherical-plus pointing with accuracies better than 0.5 degrees and supports slew rates of better than 30 degrees per second at less than 5W operational power.

Currently at TRL-4, the VORTEX gimbal features an improved design that protects vital components to make it compatible with wide temperature ranges, radiation, and chemically corrosive environments.

In the Phase I effort, we will continue development of the VORTEX gimbal by defining system requirements, improving our gimbal model and design tools, and conducting necessary trade studies to complete detailed system and sub-system designs in preparation for producing an engineering development unit that will be used for testing and flight qualification in follow-on efforts.

Potential NASA Applications

The VORTEX gimbal will support future NASA aerobot exploration missions to Venus and other planetary bodies by providing a reliable, lightweight, mechanism for pointing and articulation of high gain antennas. VORTEX is well suited for missions with instruments that require precision pointing and articulation with data or power throughput, such as optical and high-frequency RF satellite crosslinks.

Potential Non-NASA Applications

Antenna pointing and solar array articulation for both small spacecraft and extreme environments are leading use cases for the VORTEX gimbal. There is a significant amount of commercial interest in the use of the gimbal for high performance satellite cross-links and data return.

Duration: 6 months


STTR

Resin Additive Manufacturing Processed Thermal Protection Systems (RAMP TPS)
Subtopic Title: In-situ Curing of Thermoset Resin Mixtures

Tethers Unlimited, Inc.
Bothell, WA

Western Washington University
Bellingham, WA

Principal Investigator
Jesse Cushing

Estimated Technology Readiness Level (TRL) :
Begin: 2
End: 4

Technical Abstract

Tethers Unlimited, Inc. (TUI) and Western Washington University (WWU) propose to develop the “Resin Additive Manufacturing Processed Thermal Protection System” (RAMP TPS), an in-situ cured, additively manufactured, spacecraft heat shield material and process.  RAMP TPS uses Direct Ink Writing (DIW) of an optimized benzoxazine resin-based compound, filled with carbon fibers, silica micro-balloons, cure accelerators, and viscosity modifiers.

Current TPS systems are expensive to produce, and they make various compromises in their heat shield performance properties.  The RAMP TPS effort will leverage automation techniques borrowed from 3D printing, along with state of the art heat shield materials, while adding the ability to cure in-situ during robotic deposition.

RAMP TPS will offer superior mass-effectiveness through optimized material composition as well as graded low density printed core structures.  While conventional TPS resins can require hours for an oven cure process,

WWU’s Benzoxazine formulation will use accelerator additives to chemically set within minutes of deposition using the heat supplied by TUI’s feedhead assembly. Initial heat shield performance characterization will be performed using density, strain at break, thermal conductivity, TGA measurements, and thermo-oxidative ablation testing with an oxy-acetylene torch.

This novel  heat shield technology will have near term applications in lowering the cost of high-performance spacecraft production, as well as future applications within TUI’s in-space processes for automated production and servicing of re-entry vehicles.

Potential NASA Applications

RAMP TPS technology will enable cost-effective production of advanced thermal protection shields for a range of re-entry applications, including lunar exploration missions, Mars sampling missions, and asteroid sampling missions such as OSIRIS-Rex.

Potential Non-NASA Applications

RAMP TPS could enable rapid, cost-effective production of thermal protection shields for ICBM re-entry bodies.  It will also enable in-space production of large aerobrakes to support commercial ventures to obtain lunar resources such as water from the lunar poles and deliver it to propellant depots in LEO using aerobraking techniques.

Duration: 13 months