NASA Study Provides New Look at Orbital Debris, Potential Solutions
3 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
Simulation of orbital debris around Earth demonstrating the object population in the geosynchronous region.
New data analysis indicates that NASA and its partners could have more cost-effective methods for dealing with the growing issue of orbital debris than previously thought.
A new report from NASA’s Office of Technology, Policy, and Strategy provides agency leadership with new insight about how to measure the risks presented by orbital debris.
“Growing activity in Earth’s orbit has brought us everything from faster terrestrial communications to a better understanding of our changing climate,” said Charity Weeden who leads NASA’s OTPS. “These blossoming opportunities are resulting in a more crowded space environment. This study is part of NASA’s work to rapidly improve our understanding of that environment as outlined in NASA’s recently released Space Sustainability Strategy, by applying an economic lens to this critical issue.”
The OTPS Phase 1 report, released in 2023, provided initial information for policymakers looking for cost-benefit analyses of remediation measures for orbital debris including moving, removing, or reusing objects. The new report has improved the quality of the estimates of the risks posed to spacecraft by orbital debris. These new estimates cover everything from the largest debris in space down to millimeter-size fragments. The report also expands the OTPS teams’ focus to include actions that can mitigate the creation of new debris and track existing debris.
“This study allows us to start to answer the question: What are the most cost-effective actions we can take to address the growing problem of orbital debris?” said NASA analyst Jericho Locke, the lead author of the report. “By measuring everything in dollars, we can directly compare shielding spacecraft to tracking smaller debris or removing 50 large pieces of debris to removing 50,000 smaller ones.”
The new OTPS report differs from previous orbital debris studies in that it directly estimates the risk posed by space debris, instead of risk proxies like the number of pieces of debris in orbit. Additionally, it measures the risks in dollars – modeling the costs that operators would incur from maneuvering spacecraft to avoid debris, from dealing with close approaches, and from damage or loss due to debris impact. The study simulates how the orbital debris environment will evolve over 30 years.
In total, the study compares the cost-effectiveness of more than 10 different actions that can be taken to reduce the risk from orbital debris, such as shielding, tracking small debris, or remediating large debris. Eventually, the team hopes to assess the cost-effectiveness of combinations of different actions, known as portfolios.
The report’s analysis reexamines common wisdom actions the space community has historically considered cost-effective methods for supporting space sustainability. For example, the report estimates that some methods of debris remediation may be just as valuable as debris mitigation. It also estimates that quickly deorbiting defunct spacecraft is a cost-effective method of reducing risk. Such findings could provide new considerations for NASA leaders and the space community when approaching the issue of orbital debris.
OTPS plans to publicly release the research code used to produce the study. The research team plans to continue its work understanding orbital debris and the various approaches to it and will work to share its knowledge with stakeholders.
This artist’s concept shows what the warm Neptune exoplanet WASP-107 b could look like.
Why is the warm gas-giant exoplanet WASP-107 b so puffy? Two independent teams of researchers have an answer.
Data collected using NASA’s James Webb Space Telescope, combined with prior observations from NASA’s Hubble Space Telescope, show surprisingly little methane (CH4) in the planet’s atmosphere, indicating that the interior of WASP-107 b must be significantly hotter and the core much more massive than previously estimated.
The unexpectedly high temperature is thought to be a result of tidal heating caused by the planet’s slightly non-circular orbit, and can explain how WASP-107 b can be so inflated without resorting to extreme theories of how it formed.
The results, which were made possible by Webb’s extraordinary sensitivity and accompanying ability to measure light passing through exoplanet atmospheres, may explain the puffiness of dozens of low-density exoplanets, helping solve a long-standing mystery in exoplanet science.
Image: Warm Gas-Giant Exoplanet WASP-107 b (Artist’s Concept)
This artist’s concept shows what the warm Neptune exoplanet WASP-107 b could look like based on recent data gathered by NASA’s James Webb Space Telescope along with previous observations from NASA’s Hubble Space Telescope and other observatories. Observations captured by Hubble’s WFC3 (Wide Field Camera 3), Webb’s NIRCam (Near-Infrared Camera), Webb’s NIRSpec (Near-Infrared Spectrograph), and Webb’s MIRI (Mid-Infrared Instrument) suggest that the planet has a relatively large core surrounded by a relatively small mass of hydrogen and helium gas, which has been inflated due to tidal heating of the interior.
The Problem with WASP-107 b
At more than three-quarters the volume of Jupiter but less than one-tenth the mass, the “warm Neptune” exoplanet WASP-107 b is one of the least dense planets known. While puffy planets are not uncommon, most are hotter and more massive, and therefore easier to explain.
“Based on its radius, mass, age, and assumed internal temperature, we thought WASP-107 b had a very small, rocky core surrounded by a huge mass of hydrogen and helium,” explained Luis Welbanks from Arizona State University (ASU), lead author on a paper published today in Nature. “But it was hard to understand how such a small core could sweep up so much gas, and then stop short of growing fully into a Jupiter-mass planet.”
If WASP-107 b instead has more of its mass in the core, the atmosphere should have contracted as the planet cooled over time since it formed. Without a source of heat to re-expand the gas, the planet should be much smaller. Although WASP-107 b has an orbital distance of just 5 million miles (one-seventh the distance between Mercury and the Sun), it doesn’t receive enough energy from its star to be so inflated.
“WASP-107 b is such an interesting target for Webb because it’s significantly cooler and more Neptune-like in mass than many of the other low-density planets, the hot Jupiters, we’ve been studying,” said David Sing from the Johns Hopkins University (JHU), lead author on a parallel study also published today in Nature. “As a result, we should be able to detect methane and other molecules that can give us information about its chemistry and internal dynamics that we can’t get from a hotter planet.”
A Wealth of Previously Undetectable Molecules
WASP-107 b’s giant radius, extended atmosphere, and edge-on orbit make it ideal for transmission spectroscopy, a method used to identify the various gases in an exoplanet atmosphere based on how they affect starlight.
Combining observations from Webb’s NIRCam (Near-Infrared Camera), Webb’s MIRI (Mid-Infrared Instrument), and Hubble’s WFC3 (Wide Field Camera 3), Welbanks’ team was able to build a broad spectrum of 0.8- to 12.2-micron light absorbed by WASP-107 b’s atmosphere. Using Webb’s NIRSpec (Near-Infrared Spectrograph), Sing’s team built an independent spectrum covering 2.7 to 5.2 microns.
The precision of the data makes it possible to not just detect, but actually measure the abundances of a wealth of molecules, including water vapor (H2O), methane (CH4), carbon dioxide (CO2), carbon monoxide (CO), sulfur dioxide (SO2), and ammonia (NH3).
Image:Warm Gas-Giant Exoplanet WASP-107 b Transmission Spectrum (Hubble WFC3, Webb NIRCam, and Webb MIRI
This transmission spectrum, captured using NASA’s Hubble and James Webb space telescopes, shows the amounts of different wavelengths (colors) of starlight blocked by the atmosphere of the gas-giant exoplanet WASP-107 b. The spectrum includes light collected over four separate observations using a total of three different instruments: Hubble’s WFC3 (Wide Field Camera 3) Grism Spectrometer in green, Webb’s NIRCam (Near-Infrared Camera) Grism Spectrometer in orange, and Webb’s MIRI (Mid-Infrared Instrument) Low-Resolution Spectrometer in pink. This spectrum shows clear evidence for water (H2O), carbon dioxide (CO2), carbon monoxide (CO), methane (CH4), sulfur dioxide (SO2), and ammonia (NH4) in the planet’s atmosphere, allowing researchers to estimate the interior temperature and mass of the core.
Image:Warm Gas-Giant Exoplanet WASP-107 b (Transmission Spectrum: Webb NIRSpec)
This transmission spectrum, captured using Webb’s NIRSpec (Near-Infrared Spectrograph) Bright Object Spectrometer, shows the amounts of different wavelengths (colors) of near-infrared starlight blocked by the atmosphere of the gas-giant exoplanet WASP-107 b. The spectrum shows clear evidence for water (H2O), carbon dioxide (CO2), carbon monoxide (CO), methane (CH4), and sulfur dioxide (SO2) in the planet’s atmosphere, allowing researchers to estimate the interior temperature and core mass.
Roiling Gas, Hot Interior, and Massive Core
Both spectra show a surprising lack of methane in WASP-107 b’s atmosphere: one-thousandth the amount expected based on its assumed temperature.
“This is evidence that hot gas from deep in the planet must be mixing vigorously with the cooler layers higher up,” explained Sing. “Methane is unstable at high temperatures. The fact that we detected so little, even though we did detect other carbon-bearing molecules, tells us that the interior of the planet must be significantly hotter than we thought.”
A likely source of WASP-107 b’s extra internal energy is tidal heating caused by its slightly elliptical orbit. With the distance between the star and planet changing continuously over the 5.7-day orbit, the gravitational pull is also changing, stretching the planet and heating it up.
Researchers had previously proposed that tidal heating could be the cause of WASP-107 b’s puffiness, but until the Webb results were in, there was no evidence.
Once they established that the planet has enough internal heat to thoroughly churn up the atmosphere, the teams realized that the spectra could also provide a new way to estimate the size of the core.
“If we know how much energy is in the planet, and we know what proportion of the planet is heavier elements like carbon, nitrogen, oxygen, and sulfur, versus how much is hydrogen and helium, we can calculate how much mass must be in the core,” explained Daniel Thorngren from JHU.
It turns out that the core is at least twice as massive as originally estimated, which makes more sense in terms of how planets form.
All together, WASP-107 b is not as mysterious as it once appeared.
“The Webb data tells us that planets like WASP-107 b didn’t have to form in some odd way with a super small core and a huge gassy envelope,” explained Mike Line from ASU. “Instead, we can take something more like Neptune, with a lot of rock and not as much gas, just dial up the temperature, and poof it up to look the way it does.”
The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).
NASA to Start Designing More Sustainable Jet Engine Core
4 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
This artist concept shows a NASA-developed small-core jet engine installed in General Electric Aerospace’s CFM RISE jet engine design. The more fuel-efficient small core powers a large open turbofan, which also helps increase efficiency. The effort is part of NASA’s Sustainable Flight National Partnership to help inform the next generation of ultra-efficient airliners.
GE Aerospace
NASA, alongside industry, will soon begin designing a new jet engine concept for the next generation of ultra-efficient airliners — officially graduating to the project’s next phase.
As part of NASA’s goal to make the aviation industry more sustainable, the agency is developing a small core for a hybrid-electric turbofan jet engine that could reduce fuel burn by 10% compared to today’s engines.
A jet engine’s core is where compressed air is combined with fuel and ignited to generate power. By making this core smaller, fuel efficiency can be improved and carbon emissions reduced.
To achieve its ambitious goal, HyTEC is structured in two phases:
Phase 1, which is wrapping up, focused on selecting the component technologies to use in the core demonstrator.
Phase 2, starting now, will see researchers design, build, and test a compact core in collaboration with GE Aerospace.
“Phase 1 of HyTEC is winding down and we are ramping up Phase 2,” said Anthony Nerone, who leads HyTEC at NASA’s Glenn Research Center in Cleveland. “This phase will culminate in a core demonstration test that proves the technology so it can transition to industry.”
The End of the Beginning
Before researchers could start the design and build process for the core, they had to explore innovative new materials to use in the engine. After three years of notably fast progress, HyTEC researchers came up with solutions.
“We’ve been laser-focused since day one. We began the project with certain technical goals and metrics for success and, so far, we haven’t had to change course from any of them,” Nerone said.
To shrink the size of a core while maintaining the same level of thrust, heat and pressure must increase compared to standard jet engines used today. This means the engine core must be made of more durable materials that can withstand higher temperatures.
In addition to conducting materials research, the project also explored advanced aerodynamics and other key technical elements.
Cross section of a typical turbofan jet engine highlights parts of the core HyTEC will work to advance. These include the high-pressure compressor, combustor, high pressure turbine, and power extraction components.
NASA
What Comes Next
Phase 2 builds on Phase 1 to create a compact core for ground testing that proves HyTEC’s capabilities.
“Phase 2 is very complex. It’s not just a core demonstration,” Nerone said. “What we’re creating has never been done before, and it involves many different technologies coming together to form a new type of engine.”
Technologies tested in the HyTEC program will help enable a much higher bypass ratio, hybridization, and compatibility with sustainable aviation fuels.
The bypass ratio describes the relationship between the amount of air flowing through the engine core compared to the amount of air bypassing the core to flow around it.
By decreasing the core size while increasing the size of the turbofan it powers – while maintaining the same thrust output — the HyTEC concept would use less fuel and reduce carbon emissions.
“HyTEC is an integral part of our RISE program,” said Kathleen Mondino, who helps lead RISE program technologies at GE Aerospace. “GE Aerospace and NASA have a long history of collaboration to advance the latest aviation technologies. The HyTEC program builds on this relationship to help chart the future of more sustainable flight.”
Another piece of the puzzle is hybridization. HyTEC’s hybrid-electric capability means the core will also be augmented by electrical power to further reduce fuel use and carbon emissions.
“This engine will be the first mild hybrid-electric engine, and hopefully, the first production engine for airliners that is hybrid-electric,” Nerone said.
About the Author
John Gould
Aeronautics Research Mission Directorate
John Gould is a member of NASA Aeronautics’ Strategic Communications team at NASA Headquarters in Washington, DC. He is dedicated to public service and NASA’s leading role in scientific exploration. Prior to working for NASA Aeronautics, he was a spaceflight historian and writer, having a lifelong passion for space and aviation.
NASA Around the World: Interns Teach Virtual Lessons in Kenya
2 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
Video Credit: NASA/Dennis Brown, TechLit Africa
When it comes to inspiring the next generation, NASA interns know no bounds. Interns at NASA’s Glenn Research Center in Cleveland taught students 7,600 miles away in Mogotio, Kenya, but thanks to technology, they didn’t travel a single mile.
Collaborating with TechLit Africa — a non-profit organization that teaches digital skills in Kenyan rural primary schools — interns shared virtual lessons on robot simulation, artificial intelligence, and drawing and modeling applications.
Nelly Cheboi, TechLit Africa CEO and founder, enjoys a virtual reality demonstration in NASA Glenn’s GVIS Laboratory.
Credit: NASA/Jef Janis
“It was an absolute privilege to help these kids and being a part of it,” said Marc Frances, extended reality developer and former NASA Glenn intern. “We do a lot of outreach events and try to influence kids from every part of life to become an engineer and be part of something that’s bigger than themselves.”
Students learn digital skills in rural primary schools in Mogotio, Kenya.
Credit: TechLit Africa
The opportunity arose after Herb Schilling, a Glenn computer scientist, met Nelly Cheboi, TechLit Africa CEO and founder, through a virtual event in 2020. The two began talking about Cheboi’s work with Kenyan students, and Schilling felt inspired to get involved.
“I haven’t done a lot of the teaching,” Schilling said. “I let the interns do it, because I want to give them the experience and encourage them to do these kinds of things too.”
Nelly Cheboi tests a virtual reality demonstration in NASA Glenn’s GVIS Laboratory.
Credit: NASA/Jef Janis
Using a beginner-level coding application, the interns showed Cheboi’s students how to design and animate a rocket that would launch into space. After several virtual lessons, Cheboi, CNN’s 2022 Hero of the Year, and her partner, Tyler Cinnamon, visited Glenn to learn more about NASA and meet Schilling in person.
“I think it has really helped shape our curriculum, Cheboi said. “For these kids to look at this experience as something normal to them really speaks volumes of the impact. It matters what environment you grow up into, and you really can only be it if you see it.”
NASA’s Mars rover Curiosity acquired this image using its Mars Hand Lens Imager (MAHLI), located on the turret at the end of the rover’s robotic arm, on May 14, 2024, Sol 4184 of the Mars Science Laboratory Mission, at 06:58:35 UTC.
NASA/JPL-Caltech/MSSS
Earth planning day: Wednesday, May 15, 2024
The rover planning engineers yet again did a great job navigating through the large bedrock blocks that litter the terrain in front of us. We are getting ever closer to being able to cross the Gediz Vallis channel and associated deposits, a feature we identified long before landing and of high scientific interest. As a member of the group responsible for planning the observations we hope to get on the Gediz Vallis deposits and associated landforms (called the Channel Surfers), I am very excited to finally be at this point in the mission. To help decide where to drive onto the deposit, we are driving a little closer to the edge and taking extra post-drive imaging to aid in that decision. We are also acquiring a large Mastcam mosaic of an area of the deposit we hope to study in more detail, “Arc Pass.”
Before we drive, we will of course acquire lots of science observations from our current location. The workspace in front of the rover contained an interesting textured block that immediately drew all our attention – a polygonally patterned erosional feature (“Tuolumne Meadows”) that we were able to place the rover’s arm on for contact science. We will also be able to brush it and clear the dust before analyzing with APXS for chemistry and MAHLI for the fine-scale texture. ChemCam will also analyze the same spot, as well as the front face of the same block (“Wapama Falls”), which will also be documented by Mastcam. To compare with this block, we are also planning APXS and MAHLI on a separate, more typical looking bedrock block, “Parker Lakes.”
Looking a little further afield, the views continue to be stunning as we climb Mount Sharp, and so of course we wanted to document features of interest. The Yardang unit, high above us on Mount Sharp, is about to disappear from view, so we planned a ChemCam RMI mosaic to capture structures and textures. A little closer to the rover, we will also image another area of the “Pinnacle Ridge” section of the Gediz Vallis deposit to continue documenting the textures and structures associated with this relatively young feature in Gale crater.
The team also planned a series of observations to monitor environmental and atmospheric conditions. These included Navcam dust devil and suprahorizon movies, a line of sight scan and deck monitoring. Standard DAN and RAD round out this jam-packed plan.
As the APXS strategic planner this week, and as a Channel Surfer, I am excited for the downlink from this plan, and for the upcoming investigations of the Gediz Vallis deposit. To whet our appetite, we got down the results of APXS and MAHLI observations from the previous plan on an interesting textured, included block from the deposit. See the image associated with this post to marvel at the “Tenaya Lake” rock.
Written by Lucy Thompson, Planetary Geologist at University of New Brunswick
