Engineering topics

Slostad, Jeffrey

Publications and source records attributed to Slostad, Jeffrey.

3 records

NASA NTRS2018

SpiderFab: Process for On-Orbit Construction of Kilometer-Scale Apertures

The SpiderFab effort has investigated the value proposition and feasibility of radically changing the way we build and deploy spacecraft by enabling space systems to fabricate and integrate key components on-orbit. In this Phase II effort, we have focused on developing and demonstrating tools and processes to enable robotic systems to manufacture and assemble high performance structural elements that will serve as the support structures for components such as antennas and solar arrays. Through testing of these technologies in the laboratory environment,these efforts have established the technical feasibility of the key capabilities required for in-space manufacture of large apertures such as antennas, solar arrays, and optical systems,maturing prototype technical solutions for these capabilities to TRL-4. The SpiderFab effort has resulted in successful post-NIAC transition of the technology, first to SBIR-funded development of a technology for in-space manufacture (ISM) of truss structures, and then to a NASA/STMD Tipping Point Technologies funded effort to prepare a flight demonstration of ISM of a structure for a GEO communications satellite.

Manufacturing↗

NASA NTRS2013

SpiderFab(TradeMark):Process for On-Orbit Construction of Kilometer-Scale Apertures

The SpiderFab effort investigated the value proposition and technical feasibility of radically changing the way we build and deploy spacecraft by enabling space systems to fabricate and integrate key components on-orbit. Weeveloped an architecture for a SpiderFab system, identifying the key capabilities, and detailed two concept implementations of this architecture, one specialized for fabricating support trusses for large solar arrays, and the second a robotic system capable of fabricating spacecraft components such as antenna reflectors. We then performed analyses to evaluate the value proposition for on-orbit fabrication, and in each case found that the dramatic improvements in structural performance and packing efficiency enabled by on-orbit fabrication can provide order-of-magnitude improvements in key system metrics. For phased-‐array radars, SpiderFab enables order-of-magnitude increases in gain-per-stowed-volume. For the New Worlds Observer mission, SpiderFab construction of a starshade can provide a ten-fold increase in the number of Earth-like planets discovered per dollar. For communications systems, SpiderFab can change the cost equation for large antenna reflectors, enabling affordable deployment of much larger apertures than feasible with current deployable technologies. To establish the technical feasibility, we identified methods for combining several additive manufacturing technologies with robotic assembly technologies, metrology sensors, and thermal control techniques to provide the capabilities required to implement a SpiderFab system. We performed proof-of-concept level testing of these approaches, in each case demonstrating that the proposed solutions are feasible, and establishing the SpiderFab architecture at TRL-3. Further maturation of SpiderFab to mission-readiness is well-suited to an incremental development program. Affordable smallsat demonstrations will prepare the technology for full-scale demonstration that will unlock the full potential of the SpiderFab architecture by flight qualifying and validating an on-orbit fabrication and integration process that can be re-used to reduce the life-cycle cost and increase power, bandwidth, resolution, and sensitivity for a wide range of NASA Science and Exploration missions.

Hoyt, Robert↗

NASA NTRS2010

Orbital Winch for High-Strength, Space-Survivable Tethers

An Orbital Winch mechanism enables high-load, multi-line tethers to be deployed and retracted without rotating the spool on which the tether is wound. To minimize damage to the tether and the wound package during retraction or deployment under load, it can incorporate a Tension Management Module that reduces the infeed tension by a factor of 15 through the use of a powered capstan with guide rollers. This design eliminates the need for rotating high-voltage electrical connections in tether systems that use propellantless electro-dynamic propulsion. It can also eliminate the need for rotating optical connections in applications where the tether contains optical fibers. This winch design was developed to deploy a 15-km-long, 15-kg high-strength Hoytether structure incorporating conductive wires as part of the MXER-1 demonstration mission concept. Two slewing rings that orbit around the tether spool, combined with translation of one of the slewing rings back and forth along the spool axis to traverse the wind point, enables the winch to wind the tether. Variations of the traverse motion of the slewing ring can accomplish level winds and conical pirn winds. By removing the non-traversing slewing ring, and adding an actuated guide arm, the winch can manage rapid, low-drag deployment of a tether off the end of a pirn-wound spool, followed by controlled retraction and rewinding, in a manner very similar to a spin-casting reel. The winch requires at least two motor driver controller units to coordinate the action of two stepper motors to accomplish tether deployment or retraction.

Hoyt, Robert↗