Technology for Space Travel

Source: NASA

Goddard’s GIANT optical navigation software helped guide the OSIRIS-REx mission to the Asteroid Bennu. Today its developers continue to add functionality and streamline useability for future missions.

As NASA scientists study the returned fragments of asteroid Bennu, the team that helped navigate the mission on its journey refines their technology for potential use in future robotic and crewed missions.
The optical navigation team at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, served as a backup navigation resource for the OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security – Regolith Explorer) mission to near-Earth asteroid Bennu. They double-checked the primary navigation team’s work and proved the viability of navigation by visual cues.

Optical navigation uses observations from cameras, lidar, or other sensors to navigate the way humans do. This cutting edge technology works by taking pictures of a target, such as Bennu, and identifying landmarks on the surface. GIANT software – that’s short for the Goddard Image Analysis and Navigation Tool – analyzes those images to provide information, such as precise distance to the target, and to develop three-dimensional maps of potential landing zones and hazards. It can also analyze a spinning object to help calculate the target’s mass and determine its center – critical details to know for a mission trying to enter an orbit.
“Onboard autonomous optical navigation is an enabling technology for current and future mission ideas and proposals,” said Andrew Liounis, lead developer for GIANT at Goddard. “It reduces the amount of data that needs to be downlinked to Earth, reducing the cost of communications for smaller missions, and allowing for more science data to be downlinked for larger missions. It also reduces the number of people required to perform orbit determination and navigation on the ground.”

During OSIRIS-REx’s orbit of Bennu, GIANT identified particles flung from the asteroid’s surface. The optical navigation team used images to calculate the particles’ movement and mass, ultimately helping determine they did not pose a significant threat to the spacecraft.
Since then, lead developer Andrew Liounis said they have refined and expanded GIANT’s backbone collection of software utilities and scripts.
New GIANT developments include an open-source version of their software released to the public, and celestial navigation for deep space travel by observing stars, the Sun, and solar system objects. They are now working on a slimmed-down package to aid in autonomous operations throughout a mission’s life cycle.
“We’re also looking to use GIANT to process some Cassini data with partners at the University of Maryland in order to study Saturn’s interactions with its moons,” Liounis said.
Other innovators like Goddard engineer Alvin Yew are adapting the software to potentially aid rovers and human explorers on the surface of the Moon or other planets.
Adaptation, Improvement
Shortly after OSIRIS-REx left Bennu, Liounis’ team released a refined, open-source version for public use. “We considered a lot of changes to make it easier for the user and a few changes to make it run more efficiently,” he said.
An intern modified their code to make use of a graphics processor for ground-based operations, boosting the image processing at the heart of GIANT’s navigation.
A simplified version called cGIANT works with Goddard’s autonomous Navigation, Guidance, and Control software package, or autoNGC in ways that can be crucial to both small and large missions, Liounis said.
Liounis and colleague Chris Gnam developed a celestial navigation capability which uses GIANT to steer a spacecraft by processing images of stars, planets, asteroids, and even the Sun. Traditional deep space navigation uses the mission’s radio signals to determine location, velocity, and distance from Earth. Reducing a mission’s reliance on NASA’s Deep Space Network frees up a valuable resource shared by many ongoing missions, Gnam said.
Next on their agenda, the team hopes to develop planning capabilities so mission controllers can develop flight trajectories and orbits within GIANT – streamlining mission design.
“On OSIRIS-REx, it would take up to three months to plan our next trajectory or orbit,” Liounis said. “Now we can reduce that to a week or so of computer processing time.”
Their innovations have earned the team continuous support from Goddard’s Internal Research and Development program, individual missions, and NASA’s Space Communications and Navigation program.
“As mission concepts become more advanced,” Liounis said, “optical navigation will continue to become a necessary component of the navigation toolbox.”
By Karl B. Hille
NASA’s Goddard Space Flight Center in Greenbelt, Md.

Source: NASA

Lidar technology improvements will help NASA scientists and explorers with remote sensing and surveying, mapping, 3D-image scanning, hazard detection and avoidance, and navigation.

Like a sonar using light instead of sound, lidar technology increasingly helps NASA scientists and explorers with remote sensing and surveying, mapping, 3D-image scanning, hazard detection and avoidance, and navigation.
Cutting edge innovations by NASA researchers seek to refine lidars into smaller, lighter, more versatile tools for exploration.
“There are a lot of flavors of lidar right now,” said Cheryl Gramling, assistant chief for technology at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “It’s such an important technology because of the precision and versatility that it offers.”
Light detection and ranging, or lidar, is a remote sensing technology related to sonar and radar. Lidar uses pulses of light to measure distances and properties of objects accurately, by measuring the time it takes the light to reflect back to the lidar sensor.
Goddard innovators are looking to expand the usefulness of lidar applications in communication and navigation, planetary exploration, and space operations. Here are a few of the current investigations.
Foldable, Flat Lidar Optics

Research engineer Mark Stephen is developing a deployable, segmented telescope to capture the returning light signal using state-of-the-art flat-panel optics organized in foldable, origami-inspired panels. Working with researchers at Brigham Young University, their team seeks to provide future missions with the benefits of lidar technology without the current technologies’ high cost and limited efficiency.
Lidar typically is a high-cost technology that may not make the cut for tomorrow’s smaller, lighter, and more efficient missions. Size, weight, and power demands limit the technology’s ability to be implemented in more missions.
“Most people want really high performance,” Stephen said, “But they want it in a small, light, and power-efficient package. We’re trying to find the best balance, and cost matters. Often the cost comes more from the size, weight, and power than it does from the actual development if we’re launching something into space. That is where it gets expensive.”
Stephen is wrapping up a three-year effort to improve lidars through a Radical Innovation Initiative grant within Goddard’s Internal Research and Development (IRAD) program. Their project has been picked up by NASA’s Earth Science Technology Office to fund further improvements.
Typically, lidar receivers depend on bulky lenses to capture light, each lens needs a specific curvature and size to bend the light, in addition to the structures which hold the lenses, and other mechanics, Stephen said. Larger lenses are more effective, and that is where lidar technology tends to get heavy.
Flat optics use new types of nano-structured materials to manipulate individual photons, he said. These meta-materials allow thin and lightweight optics to perform the same functions as much larger and more expensive three-dimensional counterparts.

“We are working toward being able to have a family of instruments where we have some flexibility and agility to meet the needs of a given mission,” Stephen said. “We want to develop a tool where you can make a better trade in terms of size, weight and power versus performance.”
One Laser, Many Wavelengths
Goddard engineer Guangning Yang is looking to improve lidar by producing multiple wavelengths of light from a single beam. Most modern lidars use multiple beams of a single wavelength to increase their accuracy.
Yang is the primary investigator for CASALS, or Concurrent Artificially intelligent Spectrometry and Adaptive Lidar System, a lidar technology that can sweep a large area more efficiently.
CASALS starts with one laser pulse, but instead of splitting that pulse into the many directions it needs to travel, their technology changes the wavelength of the laser at a very high speed. The different wavelengths of light then exit the laser transmitter at different angles based on their wavelength.
This pulse sequence produces a broom-like array sweeping across the object, landscape, or celestial body being studied.
“We have improved the efficiency,” Yang said, “and that will allow us to reduce the instrument’s size dramatically.”
Along with improvements in efficiency, CASALS is smaller than a typical lidar instrument. Yang said CASALS could help provide higher-density mapping of Earth and of other planets and moons as well as assisting with autonomous descents and landings.
Both flat optics and wavelength scanning offer new possibilities for lidar technology and are part of an array of investigations expected to unlock new opportunities in science and navigating distant worlds, Gramling said.
By Elizabeth Markham
NASA’s Goddard Space Flight Center in Greenbelt, Md.

Category: Technology for Space Travel

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