Tech

Safe Precision Landing

 

Autonomous and human missions demand highly accurate, safe landings. Astrobotic achieves unprecedented precision and safeguarding while landing in challenging terrain. While past Moon and Mars missions landed within 10s of kilometers of an intended site, Astrobotic’s landers will land within 100m. Astrobotic’s landing technology autonomously aligns real-time data from cameras and laser with existing satellite imagery of the Moon to navigate to a precise target, identify a safe landing location, and maneuver past hazards to safely touch down.

Safe, pinpoint landings are the gateway to high-interest destinations on Mars, the Moon, and beyond that presently are avoided due to landing risks. Pinpoint landing capability enables bold missions to crater rims, caves, and peaks of persistent light; serial visits to establish and sustain habitats; and revisiting cached samples gathered on previous missions. The same technologies are ideal for penetrators and for autonomous orbital maneuvers performed very remote from Earth.

Lightweight Robotic Excavation

 

Excavation on the Moon enables compelling planetary exploration, science, and regolith operations on the Moon. Efficient soil moving techniques are essential to lay the groundwork for future human colonization by preparing terrain and mine ice and other volatiles. Astrobotic Robust, lightweight, and productive lunar excavation robots effectively address this need.

The key challenge in excavation on other planets is mass. Mass equates to cost in terms of fuel to launch and land necessitating low mass solutions. Low mass machines in low gravity environments can only produce limited traction with which to generate the substantial forces to dig dirt. Astrobotic’s innovative low-mass design incorporates a bucket-wheel, a high-volume dump bed, and composite materials.

  • The bucket-wheel keeps excavation resistance low by taking only small bites of regolith at a time. High production is maintained by taking a large number of these small bites repeatedly.
  • A high-volume dump bed increases an excavator’s payload ratio (ratio of weight of regolith carried to empty robot weight). This pound-for-pound regolith moving capacity governs the productivity of small machines.
  • Composite materials, such as carbon fiber and Kevlar, provide significant strength and stiffness to mass advantages over metal structures, dramatically reducing mass.

 

Planetary Cave Exploration

Sub-surface caverns may be the best place for human habitation on the Moon and to find life on Mars. They can provide a window into a planet’s history of geology, climate, and biology. Skylights provide access to sub-surface voids. They have been conclusively shown to exist on Mars and the Moon and some evidence points to existence throughout the solar system. Robotic precursor missions will map and characterize skylights and sub-surface caverns for future human missions and they can gather scientific data at sites where humans may never go.  Planetary caves provide a challenging mission environment. Unlike surface explorers, robots in caves cannot get power from the sun, nor can they use the sun’s light to illuminate the terrain for photography. Emerging technologies, such as magneto-inductive radars, can provide a low bandwidth data link into a cave, but this data link is nowhere near enough for teleoperation, so cave exploring robots must operate with a high degree of autonomy. Accessing lava tube caves through skylights presents a difficult mobility challenge, including both vertical descent and navigation of rubble piles.

Astrobotic innovates technologies for robotic exploration of skylights and lava tubes.  Complementary flyover and surface rover modeling of skylights provides detailed reconnaissance data. Astrobotic’s precision navigation and hazard avoidance technology enables a lander to fly near a skylight at low altitude. Lander flyover captures detailed overview data, as well as perspectives that cannot be observed from a rover viewpoint. A rover can capture close-up images of the terrain, and it can linger to capture multiple views from stationary locations, though always from low, grazing perspectives. Alternately, a lander can acquire bird’s-eye views but with less detail and resolution since its one-pass, always-moving trajectory is constrained by fuel limitations. Lander and rover data are combined, using lander data to localize and plan rover paths, to autonomously construct a quality 3D model of a skylight.  Astrobotic is developing robots, autonomy, and missions to meet the power, sensing, comm, autonomy and mobility challenges of skylight and cave exploration. This effort benefits from the deep experience of Astrobotic engineers and Carnegie Mellon University partners in subterranean robotics.

Driveline

Dust abrasion, thermal extremes, harness-bending, actuator minimization, and lubrication failure are the major challenges for planetary rovers. For reliable long-life operation under extreme environmental conditions in space, drivelines must move beyond the exposed hub motors, high reduction ratio, minimal capability, low duty cycle, and the short-range paradigm of planetary rover mobility. Traditional hub motors locate sensitive high-speed shafts at the location of worst-case thermal extremes and dust intrusion, limiting component and lubrication options and imposing mass and complexity for thermal regulation. Hub motors also require wiring through motions of suspension and steering.

Astrobotic innovates inboard drivelines that locate motors and gear reductions in clean, thermally regulated robot interiors grounded to the chassis and efficiently transfers torque to the exterior mechanisms (e.g., wheels and tools) through lightweight roller chain. Components in rover interiors benefit from close coupling to avionics thermal control (e.g., passive radiator cooling, active fluid control, or radioactive heating). This also enables choice of lubricant and use of a lubricant reservoir to recycle lubricant.

Astrobotic’s robot drivelines couple actuation, moving from traditional one actuator per wheel drive and one actuator per steered joint to two total actuators, one per side with torque transfer to all wheels on that side. Steering is by skidding. Using only one actuator per side is a game-changer – the ability to introduce significant margin in actuation. By serving all mass allocation with two actuators, larger motors can be used with lower gear reductions and significant margin on torque. This dramatically reduces cycles at motor per distance and increases cycle life by operating with 10x torque margin. The resulting long cycle life, high torque transfers, and operability in abrasive dust and thermal extremes deliver increased rover mobility and reliability.

Structural and Thermal Composites for Planetary Rovers

Structural and thermal composite materials solve a fundamental space robotics problem. Lightweight, stiff structures have a cascading effect reducing actuator loads, power loads and increasing payload ratio. This effect is compounded further when multi-axis manipulators or mobility is considered. Implementation to date is often limited to quasi-isotropic composite plate and tube, commonly known as “black aluminum”. Integrating tailored composites early in the development of robotic platforms achieves game-changing mass reductions. Composites play a key role in thermal systems of lunar rovers, which are exposed to temperature extremes ranging between -175°C and 120°C. Thermally conductive composites are used for lightweight thermal management of sensitive components.  Composite structures and thermal components are mission enablers for Astrobotic spacecraft. Components are numerous and far reaching such as rover chassis, I-Beam, thermal strap, battery case and wheels.

 

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