Category: Science

TAMPA, Fla. — The two contenders hoping the U.K. chooses them to de-orbit a pair of derelict satellites in 2026 with a single robotic spacecraft have finished the system requirements review for their mission. 

The British subsidiary of Japan’s Astroscale announced Oct. 10 it had completed this early phase of the mission after meeting the UK Space Agency (UKSA) in August, when technical requirements that include the initial design of a robotic arm were reviewed.

Switzerland-based ClearSpace’s U.K. unit said in June it had completed its system requirements review — a key milestone in a satellite development phase where a spacecraft’s functionality, design, and operational objectives are examined. 

The reviews were done under UKSA contracts worth a combined £4 million ($5 million) awarded last year and set to culminate by early 2024 with a   preliminary design review, a more thorough examination of technical, regulatory, and other requirements. 

UKSA is then expected to select one of the early-stage debris-removal ventures by the end of June to move ahead with the mission in low Earth orbit (LEO), Rory Holmes, ClearSpace’s U.K. managing director, told SpaceNews.

ClearSpace bid

Holmes said its spacecraft leverages the core robotic and sensor payloads designed for its first debris-removal mission, ClearSpace-1, slated to launch in 2026 to grapple and then remove the upper stage of a Vega rocket from LEO under a European Space Agency contract.

The spacecraft for the U.K. mission would be heavier than the 700-kilogram ClearSpace-1, because it would need to carry additional fuel to reach and de-orbit a second piece of debris.

He said the satellite supply chain would also be more concentrated in the United Kingdom, and the spacecraft would be designed to be refueled in LEO so it could potentially remove more debris after the first two.

“The mission to be taking place in 2026 is progressing rapidly, with key technology demonstrations, including Proximity Operations and the Relative Navigation and Capture System, currently undergoing testing in the UK,” he said via email.

He said names of the target satellites will be disclosed shortly in partnership with their owners. 

“The debris that we’re aiming for are derelict UK satellites that currently are in congested orbits where many of the operational satellites in LEO are located,” he added.

Astroscale challenge

Astroscale has also not disclosed the pair of satellites it plans to de-orbit for UKSA, which requires them to have been sent to LEO under a U.K. license.

According to satellite tracker and astrophysicist Jonathan McDowell, at least 14 candidates meet this criteria. Astroscale and ClearSpace may be targeting the same satellites.

Astroscale intends to use a variant of a servicer with a mass of a few hundred kilos launching in 2025 for its End of Life Services by Astroscale-Multiple mission, or ELSA-M.

Unlike the 2026 mission, ELSA-M would use a magnetic capture mechanism to attach to and then de-orbit a OneWeb satellite previously fitted with a magnetic docking plate.

Astroscale is also in the running to remove an upper stage of a discarded H-2A rocket in LEO without a docking plate for Japanese space agency JAXA.

The launch of a precursor to that removal mission, a 150-kilogram Active Debris Removal by Astroscale-Japan (ADRAS-J) spacecraft that would rendezvous and inspect the debris, was set to launch in November but is on hold following Rocket Lab’s Sept. 19 launch failure.

In 2021, Astroscale used a magnetic mechanism on a 175-kilogram demonstrator to attach and then detach from a 17-kilogram client craft that had launched along with it. 

This End-of-Life Services by Astroscale-demonstration (ELSA-d) was supposed to end with the servicer recapturing the client for a controlled descent that would have seen them jointly burn up in the Earth’s atmosphere. 

However, the ELSA-d servicer lost half its thrusters and will instead de-orbit by the end of this year without its partner, which will be left to decay over the next several years naturally.

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Wildly missed revenue projections cast a long shadow over space firms that went public by merging with a SPAC, or special purpose acquisition company, as their shares continue to underperform in the market.

Most that joined the recent hype around merging with these publicly listed shell companies announced their deals in 2021, and the majority of them also closed that year to raise significant sums for cash-intensive businesses.

SPAC mergers do not require the intensive due diligence of a traditional IPO process, leaving companies vulnerable to making lofty financial forecasts to drum up investor support.

While most post-SPAC space firms continue to point to a massive backlog of revenues from eager customers, they have struggled to hit even near-term financial goals.

Of those that held investor presentations in 2021 for their SPAC tie-up, only Rocket Lab beat the revenue target it made for the following year. Planet hit its projection, and Terran Orbital was just 2% under. The rest were significantly off the mark.

However, all post-SPAC space firms look to be coming in short of the 2023 predictions they made in 2021 — even Rocket Lab, which now expects to make around $67 million in the third quarter of 2023 after reporting $117 million in revenue for the first half. That is some $83 million shy of its earlier $267 million forecast for 2023 that it will need to make up for in the fourth quarter.

Rocket Lab lowered revenue expectations for the third quarter by $6-10 million Sept. 26, a week after a launch failure forced it to delay at least one future mission.

Missed revenue targets add another weight to share prices already under pressure from tough macroeconomic conditions, reducing the value of these companies and their options for raising more capital. Virgin Orbit collapsed into bankruptcy in April after running out of cash to keep its operations running.

Momentus, which announced its SPAC deal just ahead of the 2021 rush, holds the record for falling shortest of the mark it set for itself. The space tug specialist reported $299,000 in revenue for 2022, less than 1% of the $152 million it told investors to expect.

Jason Rainbow’s Connecting the Dots column originally appeared in the October 2023 issue of SpaceNews magazine.

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New research demonstrates the power of rhythm as a design element in evolution and robotics.

As the internet quickly fills with viral videos of futuristic robots darting and racing around like the animals they’re built to mimic, researchers say that there’s an element of their movement’s programming that should not be overlooked: rhythm.

When analyzing legs, wings, and fins for moving robots or animals in the real world, the mathematics looks fairly straightforward. Limbs with multiple sections of various lengths create different ratios for leverage, bodies with alternate shapes and sizes create drag coefficients and centers of mass, and feet, wings, or fins of various shapes and sizes push on the world around them.

All of these options create more degrees of freedom in the final design. But until now, say the researchers, nobody was paying much attention to the timing of how they’re all working together.

“Minimizing the amount of work being done by varying the speed over the mover is an idea that’s been around a long time,” says Adrian Bejan, a professor of mechanical engineering at Duke University. “But varying the rhythm of that movement—the music of how the pieces move together over time—is a design aspect that has been overlooked, even though it can improve performance.”

The reasoning and mathematics exploring this thesis appears in the journal Scientific Reports.

To illustrate his point in the paper, Bejan points to natural swimmers such as frogs or humans doing the breaststroke. Their swim gate is characterized by three time-intervals: a slow period of reaching forward, a fast period of pushing backward, and a static period of coasting. For optimum performance, the lengths of time for those intervals typically go long, fast, long. But in certain situations—outracing or outmaneuvering a predator, for example—the ratios of those periods change drastically.

In the design of robots built to emulate dogs, fish, or birds, incorporating different rhythms into their standard cruising movements can make their normal operations more efficient. And those optimal rhythms will, in turn, affect the choices made for all of the other pieces of the overall design.

The work builds on research Bejan published nearly 20 years ago, where he demonstrated that size and speed go hand-in-hand across the entire animal kingdom whether on land, in the air, or under water. The physics underlying that work dealt with weight falling forward from a given animal’s height over and over again.

In this paper, Bejan shows that his previous work was incomplete, and that all animals, robots, and other moving things can further optimize their mechanics by adding an element of rhythm.

“You can—and indeed you should—teach rhythms of movements to competitive swimmers and runners looking for an edge,” Bejan says. “Rhythm increases the number of knobs you can turn when trying to move through the world. It is yet another example of how good design—whether made by humans or through natural evolution—is truly a form of art.”

Source: Duke University

A new study shows a decline in bird biodiversity across urban and agricultural areas of the United States.

The decline stems from human activities modifying or disturbing birds’ habitats, according to the study in the journal Ecography.

“We know anthropogenically modified environments can negatively impact biodiversity by decrease the number of species,” says Corey Callaghan, assistant professor of global ecology at University of Florida Institute of Food and Agricultural Sciences’ Fort Lauderdale Research and Education Center. “In our study, we learned that as you go from natural areas to human-modified areas, the number of individuals that can persist decreases, which then influences species richness.”

Although much research has highlighted patterns of bird diversity and how changes occur along different urban and agricultural environments, the scope of change has been challenging to confirm, as have the conditions by which the change occurs.

“Luckily, citizen science datasets such as eBird allow for increasingly broad-scale studies in space and time, which provide an exceptional dataset to answer some of these questions,” says Callaghan.

For the study, scientists used a combination of datasets. They started by compiling bird data from the eBird citizen science app. The eBird app enlists volunteer birders to submit checklists of all bird species and the abundance of each species they hear and/or see while birding. eBird is among the world’s most significant biodiversity-related science projects, with users around the work contributing more than 100 million bird sightings annually.

Using more than 90,000 of these checklists from across the continental US, the scientists found strong evidence of an overall decline in bird diversity along a human-modified gradient, from natural areas to areas with high human activities, such as urban or agricultural areas.

Callaghan highlights that this result is “unimodal,” meaning that there is a peak in diversity around the rural-suburban interface. This suggests that small and local actions can have a positive effect on biodiversity. In other words, despite the decline of bird diversity in urban environments, scientists say there is still hope for building biodiversity bird species in urban areas so long as humans adopt inviting changes to their surrounding environment.

Callaghan suggests introducing native plants and shrubs to landscapes, researching, and placing the right bird feeder for your area, and providing wildlife cover. If you must cut down a standing dead tree or one dying due to disease, lightning, or animal damage, consider leaving the lower trunk as a snag. Snags serve as inviting nesting cavities for woodpeckers for example. On a grander scale, municipalities and communities can implement urban forests and utilize urban forest remnants as buildings for birds to influence and promote bird conservation in urban areas.

Source: University of Florida

WASHINGTON — A startup has raised a seed round of funding to develop customized satellites with the assistance of artificial intelligence as an alternative to standardized buses.

Los Angeles-based Proteus Space announced Oct. 10 that it raised a $4.2 million seed round led by Moonshots Capital. Other investors participating in the round included Lavrock Ventures, The Veteran Fund, Mana Ventures, AIN Ventures, Capital Factory and Industrious Ventures.

Proteus will use the funding to advance its technology to enable rapid development of customized small satellites using AI, which the company argues can rapidly shorten the time to develop those satellites without requiring payloads to confirm to requirements of a more standardized satellite.

“You can’t win the new space race when it takes you three years to get to the starting line,” said David Kervin, chief executive of Proteus Space, in an interview. “The whole goal here is to end up in a place where somebody can come in and say, ‘I want a bus built,’ and six months later they have something ready to launch.”

Company executives say that they expect to be able to complete the design of a customized satellite in 30 days, versus the 18 months of traditional approaches. Machine learning can help speed up the iterative phases of satellite design, they argue, while other AI approaches like deep learning could eventually help identify design solutions more quickly than a human could.

“We’re really focused on rapidly designing new buses for new kinds of payloads to proliferate that technology as quickly as possible,” he said. “We’re talking about new kinds of buses with the same or less risk than a standard bus.”

The company has disclosed few details about the capabilities of the satellites they expect to produce beyond them being ESPA-class, weighing a couple hundred kilograms. The company expects to produce those satellites using some amount of additive manufacturing, said Terry Gdoutos, vice president of spacecraft systems, based on the designs that result, but will also incorporate traditional manufacturing techniques.

“You have to be very selective with when it makes sense to use that,” said Andrew Shapiro, chief technology officer of Proteus Space, of additive manufacturing. “We’re very careful about using it when it’s appropriate.”

The funding will enable the seven-person startup to hire more developers to create the end-to-end satellite design system and build out its manufacturing capability. An initial version of that system should be operational by next summer, Kervin said.

Proteus Space is targeting commercial and government customers who would prefer to design a satellite around their payload rather than modify their payload to conform to a standardized satellite. Kervin said the company has a pipeline of about $100 million of potential business from both startups and established space companies, as well as government agencies, although it has yet to announce any contracts.

That approach attracted investors like Moonshots Capital. “We were impressed by the Proteus Space technical concepts and mission focus,” said Craig Cummings, general partner at Moonshots Capital and member of the board of directors of Proteus Space, in a statement. “We are confident their extraordinary leadership, domain expertise, and determined resolve will carry the company to success.”

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A new theory may explain how gold, platinum, and other precious metals found their way to shallow pockets within Earth’s mantle rather than deep in the planet’s core.

More broadly, the new theory offers insights into planet formation throughout the universe.

The new work provides valuable information about the story of gold. It’s a story that begins with violent collisions of large objects in space, continues in a half-melted region of Earth’s mantle, and ends with precious metals finding an unlikely resting spot much closer to the planet’s surface than scientists would have predicted.

“Our research is a good example of making an unexpected discovery after re-examining conventional wisdom,” says Jun Korenaga, a professor of earth and planetary sciences at Yale University.

Korenaga and Simone Marchi, a researcher at SRI in Boulder, Colorado, are coauthors of the study in the Proceedings of the National Academy of Sciences.

Recent research from scientists around the world has established that precious metals such as gold and platinum came to Earth billions of years ago after the early proto-Earth collided with large, moon-sized bodies in space, which left behind deposits of materials that were folded into what is today’s Earth.

But that absorption process has remained something of a mystery.

Aside from being valued for their scarcity, aesthetic beauty, and use in high-tech products, gold and platinum are what is known as highly “siderophile” elements. They are drawn to the element iron to such a degree that they would be expected to collect almost entirely in Earth’s metallic core—either by merging directly with the metal core on impact or by sinking quickly from the mantle into the core.

By this logic, they should not have collected at or near the Earth’s surface. Yet they did.

“Working with Simone, who is an expert on impact dynamics, I was able to come up with a novel solution to this conundrum,” Korenaga says.

Korenaga and Marchi’s theory centers around a thin, “transient” region of the mantle, where the shallow part of the mantle melts and the deeper part remains solid. The researchers found that this region has peculiar dynamic properties that can efficiently trap falling metallic components and slowly deliver them to the rest of the mantle.

Their theory posits that this delivery is still ongoing, with the remnants of the transient region appearing as “large low-shear-velocity provinces”—well-known geophysical anomalies in the deep mantle.

“This transient region almost always forms when a big impactor hits the early Earth, making our theory quite robust,” Marchi says.

The researchers say the new theory not only explains previously enigmatic aspects of Earth’s geochemical and geophysical evolution, but it also highlights the wide range of time scales involved in Earth’s formation.

“One of the remarkable things we found was that the dynamics of the transient mantle region take place in a very short amount of time—about a day—yet its influence on subsequent Earth evolution has lasted a few billion years,” Korenaga says.

NASA and the National Science Foundation funded the work.

Source: Yale University

WASHINGTON — SpaceX Chief Executive Elon Musk says it will be about a year before the company’s new Starship vehicle will be ready to start launching satellites.

Musk, speaking virtually at the International Astronautical Congress (IAC) in Baku, Azerbaijan, Oct. 5, said he felt that the vehicle would be able to start launching SpaceX’s advanced Starlink satellites even before the company had demonstrated the ability to safely recover both stages of the vehicle.

“There’s a good chance we start deploying Starlink V3 satellites next year, in roughly a year from now,” he said. The company has not previously disclosed a version 3 of its Starlink satellites; it previously said it would launch full-sized V2 satellites on Starship rather than the smaller “V2 mini” satellites currently being launched on Falcon 9.

Those launches, he suggested, could begin before mastering recovery of both the Super Heavy booster and the Starship upper stage, or ship. “The hardest part about this, or the part that will take the longest, is solving for safe ship reentry and landing,” he said. “Before we solve that, we can launch the satellites because, in any case, with Falcon 9 the upper stage is expendable. It’s actually fine to start launching satellites even before we solve for ship reusability.”

Musk offered few new details about Starship itself, which is awaiting regulatory approvals for its second test flight after an inaugural launch in April. He noted that SpaceX has shifted to a passive stage separation system between the booster and ship to eliminate parts, as well as previously announced plans to perform “hot staging” where the ship ignites its engines before separating from the booster.

He reiterated a cautious optimism about the chances of success for that upcoming launch. “I want to set expectations not too high,” he said. “If the engines light and the ship doesn’t blow itself up during stage sep, then I think we’ve got a decent chance of reaching orbit.”

As with the planned profile for the first flight in April, the upcoming flight will not complete a single orbit, with the ship splashing down near Hawaii. That is linked to the gradual approach SpaceX is taking to recovering and eventually reusing the vehicle.

Neither the booster nor the ship will be recovered on the upcoming flight. The booster, he said, could be recovered within the next year, he said, by flying it back to the launch site and catching it with arms extending from the launch tower, a contraption dubbed “Mechazilla.”

Recovering the ship will take longer. “We want to make sure that it comes in fully intact and lands in a precise location in the Pacific before we try to catch it at the launch site,” he said. “Hopefully, we might catch the ship towards the end of next year.”

Musk, though, is known for setting timelines that the company does not meet. Later in the presentation he said that he expected the first Starship mission to Mars to take place in three to four years. At his previous appearance at the IAC in 2017, in Adelaide, Australia, he offered an “aspirational” goal of initial cargo missions to Mars in 2022.

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Advanced practical registered nurses would benefit from formalized and standardized education and about treating breast cancer survivors, a study finds.

By 2040, an estimated 26 million Americans will be living as survivors of cancer. While advances in technology and medical treatments have increased their survival rates, cancer survivors are still at a higher risk than the general population for both a return of their cancer or a new type of cancer forming. They are also at higher risk for developing cardiovascular issues and lymphedema, a chronic condition of swelling caused by disruptions to the body’s lymphatic system.

In a new study at the University of Missouri, researchers found that Advanced Practice Registered Nurses (APRNs) recognized the importance of breast cancer survivorship care and were willing to proactively plan the best next steps for their patients. Education on the topic would likely improve and streamline the health care provided by the APRNs, who are well-positioned to care for the growing population of cancer survivors.

According to Allison Anbari, an assistant professor in the University of Missouri’s Sinclair School of Nursing who led the study, by approaching cancer survivorship as a chronic condition, similar to hypertension or diabetes, researchers can equip clinicians with the information they need to in turn help better educate cancer survivors, thus improving their long-term health outcomes.

To better understand the experiences of APRNs caring for breast cancer survivors, Anbari interviewed APRNs about how they were helping plan care for their patients as well as potential areas for improvement.

“What we found is that while APRNs are doing a great job, they were often learning about breast cancer survivorship care on the job and used previous experiences of helping breast cancer survivors to inform current or future care plans for patients,” Anbari says. “If we start to think of cancer survivorship as a chronic condition, similar to hypertension, we can create a more formalized, standardized approach that provides clinicians with more systematic and streamlined trainings, resources, and education so that they can be even more successful going forward.”

The findings could lead to more formalized education, including lectures or webinars, specifically about cancer survivorship when they are in residency, in practicum, in clinical rotations, or as undergraduate students.

“Educating patients about symptom management, monitoring their body, continued surveillance screenings, echocardiograms, and clinical breast exams is crucial,” Anbari says. “Basic things like healthy diet and exercise can reduce the chances of cancer coming back or new cancers forming. Also, asking more holistic questions about stress, mental health, mammogram scheduling, and follow-up appointments with oncologists can be extremely helpful as well.”

As a two-time breast cancer survivor herself, Anbari received six chemotherapy agents, immunotherapy, two types of radiation, two surgeries, reconstruction, and physical therapies.

“Patients with diabetes get formally educated with programming and education about all kinds of things like foot health, skin health, and the glycemic index of foods, but the information for cancer survivors is currently not as formalized or standardized,” Anbari says. “If we can help streamline the process for clinicians to have the education and resources they need, the trickle-down effect of what the patients learn will ultimately improve their health outcomes.”

Anbari adds that emerging technologies, such as electronic health records and telehealth, can play a critical role in assisting APRNs and other non-oncology clinicians.

“As the number of cancer survivors continues to go up, this topic will only become more important going forward, and my goal is to help others who may not have had the same privileges or health care access that I had,” Anbari says. “APRNs are in a great position to help, as they have advanced training in health assessment and early illness detection, in pharmacology, and in diagnostics. As researchers, it is our job to support them, which ultimately helps their patients.”

The study appears in the Journal of the American Association of Nurse Practitioners.

Source: University of Missouri

TAMPA, Fla. — SpaceX called on the Federal Aviation Administration to correct a report to Congress warning that, by 2035, falling debris from U.S.-licensed constellations in low Earth orbit (LEO) could injure or kill someone every two years if they deploy as planned.

In an Oct. 9 letter to the FAA and Congress seen by SpaceNews, SpaceX principal engineer David Goldstein said the report relied on “deeply flawed analysis” based on assumptions, guesswork, and outdated studies. The letter came four days after SpaceNews contacted the company with questions about the report, published Oct. 5 on the FAA’s website.

In the report, the regulator said 28,000 hazardous fragments from de-orbiting satellites and the rockets that launch them could be surviving reentry each year by 2035 — particularly if SpaceX’s rapid Starlink expansion plans remain on track.

SpaceX has launched 5,000 Starlink satellites since 2019, has permission from the U.S. Federal Communications Commission to grow the constellation to 12,000, and is seeking international approvals to eventually expand to 40,000 Starlinks in orbit. According to the FAA report, Starlink represents more than 85% of the expected risk to people on the ground and aviation from falling debris in the timeframe.

The FAA was directed by Congress in 2020 to issue a report on the risks associated with the reentry disposal of satellites from LEO megaconstellations. In 2021, the FAA commissioned the Aerospace Corp., a federally funded nonprofit focused on space, to provide a technical assessment of the rise of LEO constellations and the risks posed to aviation and people on the ground by unplanned and controlled reentries of these satellites and the upper stages that launch them. 

The FAA told Aerospace Corp. to focus on non-geostationary satellites launched by the United States under FAA licenses, so the analysis excluded constellations such as China’s proposed 13,000-satellite Guowang network. 

The Aerospace Corp. also concluded the probability of “an aircraft downing accident” in 2035 at 0.0007 per year as a result of falling debris, which would likely kill all onboard.

However, the FAA conceded any “rise in reentry risk is minimal over the current risk” if SpaceX is correct in reporting zero surviving Starlink debris to date, and that their components are fragile enough to burn up entirely in the atmosphere.

“By 2035, if the expected large constellation growth is realized and debris from Starlink satellites survive reentry, the total number of hazardous fragments surviving reentries each year is expected to reach 28,000, and the casualty expectation, the number of individuals on the ground predicted to be injured or killed by debris surviving the reentries of satellites being disposed from these constellations, would be 0.6 per year, which means that one person on the planet would be expected to be injured or killed every two years. 

“Some debris fragments would also be a hazard to people in aircraft. Projecting 2019 global air traffic to 2035 and assuming that a fragment that would injure or kill a person on the ground also would be capable of fatally damaging an aircraft, the probability of an aircraft downing accident (defined in the Aerospace report as a collision with an aircraft downing object) in 2035 would be 0.0007 per year.”

Excerpt from FAA report to Congress: Risk Associated with Reentry Disposal of Satellites from Proposed Large Constellations in Low Earth Orbit

According to satellite tracker and astrophysicist Jonathan McDowell, 358 Starlink satellites have de-orbited. There have been no reports of their debris reaching the ground.

“To be clear, SpaceX’s satellites are designed and built to fully demise during atmospheric reentry during disposal at end of life, and they do so [emphasis in original],” Goldstein wrote in the letter.

“Extensive engineering analysis and real-world operational experience verify this basic fact.”

The FAA based its conclusions on a claim that the space industry has not met the 90% success rate for post-mission disposal, he added, whereas he said SpaceX’s post-mission disposal success rate is greater than 99%.

Goldstein also said the analysis improperly leveraged a 23-year-old NASA study that found roughly one piece of debris survives reentry for every 100 kilograms on Iridium Communications satellites — a much smaller LEO constellation.

“The analysis is inapplicable to SpaceX satellites because — among other things — Iridium satellites were not even built to be fully demisable,” he said, and are “not similar in material, construction, design, orbit and operation from SpaceX or any other modern satellite in LEO.”

The FAA was unable to comment because Oct. 9 is a federal holiday in the United States.

Tricky work

Determining the exact risk from reentering satellites is difficult due to the uncertainties in reentry survivability calculations, Marlon Sorge, executive director of Aerospace’s Center for Orbital and Reentry Debris Studies, told SpaceNews via email Oct. 5.

“The phenomenology is quite complex and the available ‘ground truth’ data is limited,” Sorge said, and the exact results are also highly dependent on the specifics of satellite designs.

“As you can imagine it is very difficult to get ‘ground truth’ data on what survives reentry by observing actual reentries as they occur randomly all over the world, not usually in convenient locations,” he added.

Rather than trying to predict the future, he said the analysis sought to understand how behaviors lead to reentry consequences, so action can be taken to reduce potential risks. 

“This kind of information helps in planning for possible future rule changes given the increased traffic that is possible in the future,” he said.

According to Goldstein, Aerospace Corp did not seek to review Starlink’s demisability analysis, and its “errors may have been avoided if Aerospace had simply made basic inquiries with SpaceX, but it elected not to do so.”

Goldstein also slammed Aerospace Corp. and the FAA for failing to update figures in the 2021 analysis for the size of constellations before submitting it to Congress. 

While the report assumes 54,902 FCC-licensed satellites are in space across 12 filings from nine operators, updated regulatory filings have reduced this number by 7,518.

In addition to excluding constellations licensed by China and other foreign governments, Goldstein said the analysis failed to sufficiently consider U.S.-based Amazon’s plans to begin launching its proposed constellation of more than 3,200 satellites next year.

“The fact FAA simply accepted the Aerospace report without question or scrutiny raises concerns regarding FAA’s technical competence to responsibly assess and regulate in this area,” Goldstein wrote.

Rocket debris risk

As well as satellite reentries, the FAA report highlighted the increasing risk of falling debris from the rise in launches needed to deploy and sustain large LEO constellations. 

The U.S. commercial rockets that launch large constellations typically leave their upper stage in orbit, which the report noted usually has more mass than individual satellites “and therefore poses a greater reentry risk to people on the ground.”

Whereas 60 Starlink first-generation satellites have a total mass of just over 17 tons, an upper stage of the Falcon 9 that launched them to LEO is over 25 tons.

The report also pointed to the reentry of a Falcon 9 upper stage in March 2021 following a Starlink launch that “could have landed anywhere from 53 degrees south to 53 degrees north latitude.”

Wreckage from the core stage of a Chinese Long March 5B rocket that reentered into Earth’s atmosphere two months later was widely criticized in the U.S. and elsewhere.

Although the debris fell into the ocean, where most random reentries end up because water covers 70% of the Earth, the FAA said the risk of large objects reentering over populated areas remains.

“Despite guidelines recommending purposeful reentry, large space objects reenter the Earth’s atmosphere roughly once a week,” the report added. 

“Some are recently launched, and many more were launched prior to any agreed-upon disposal strategies.”

The U.S. government tracks reentries, but the FAA said it can’t predict them accurately enough to provide meaningful warnings to those in danger.

“As a rule of thumb, a reentry time can be off by ten percent of the orbital time remaining,” the report warned. “This means that 10 hours before reentry, the predicted reentry time can be off by one hour.”

Goldstein’s letter to the FAA did not touch on the risk of injury or death from rocket reentries.

The FAA published draft regulations in September that would require U.S. commercial launch providers to deorbit spent upper stages post-launch, primarily to reduce risks of orbital debris but also to limit risks to people on the ground from uncontrolled reentries.

However, the FAA said it does not have the authority to adequately address the risks associated with satellite constellations reentering from LEO.

An FAA rule-making on this matter depends on whether other agencies — the FCC or Department of Commerce — choose to begin their own process for regulating the reentry of constellation-related debris.

Oct. 10 update: Aerospace Corp. told SpaceNews via email that its technical team is in communication with SpaceX and others to review and update the data. An FAA spokesperson said it is reviewing SpaceX’s letter.

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A haptic device called JumpMod uses vertical force-feedback to mimic the full-body feeling of gravity.

The technology is housed in a compact, wearable backpack and modifies the user’s perceived jump.

Immersive technology, like interactive sports or virtual reality, has leveraged the power of motion sensors to create a unique way for humans to interact with computers. While the technology does add a new layer of depth to a novel, at-home experience, it often falls short of realism for one critical reason: The sensors can’t provide a full-body sensation without large enough equipment capable of moving an entire human body.

A group of scientists from the Human Computer Integration Lab at the University of Chicago’s computer science department have been working on a solution to tackle that problem.

The new JumpMod technology lives within a compact, wearable backpack and modifies the user’s perceived jump through five different effects: the feeling of jumping higher, landing harder or softer, and being pulled higher or lower.

The portable, untethered nature of JumpMod marks a distinct difference in comparison to other solutions. The backpack does not use any outside handles, platforms, or grounding technology, nor does it actually lift or move a person— which would allow access to hyper-realistic, immersive experiences at home a possibility in the not-so-distant future.

“If you want to modify the way you feel about gravity, then traditionally, you would need a motion platform, to go to a theme park and ride a roller coaster, or have an entire infrastructure with cables that can pull you up,” says PhD student Romain Nith.

“That all requires large machines and a lot of power as well. It’s obviously not practical to have those things inside your house if you are trying to experience similar sensations on a daily basis. So I’ve been investigating if there are ways we can shrink them down to a more manageable form.”

While it might seem like a simple problem to fix, gravity doesn’t necessarily work in favor of scalability.

“The reality is there hasn’t been an easy way to create these types of full body sensations because the physics don’t work,” explains Pedro Lopes, an associate professor. “We asked ourselves how it would be possible to generate the feeling of these large forces in a scalable device that could also still trick the human senses. JumpMod is one of the solutions we have landed on.”

In VR and other similar modalities, a lot of scientists have looked at the sensory experience on a horizontal field, leaving the vertical space much less explored. For example, creating the sensation of walking slowly by adding wind resistance can be an easy experience to recreate because you can simply add a fan to the space without having to do much else. However, recreating the feeling of gravity when moving up or down is a trickier process. When the team started experimenting with vertical space, they found that adding weight to the body in a controlled way was a great way to mimic the force of gravity.

A small weight in the JumpMod backpack moves up and down the user’s back in combination with a motor to add acceleration. At specific moments in a virtual reality experience, the weight and motor are activated to create a pull or push on the body. If the user is trying to jump over something, the weight and motor moves toward the top of the backpack in tandem with the user’s movement. Once the user lands, the weight moves down at an accelerated speed to create the feeling of absorbing impact.

The team has tested JumpMod in the context of a virtual reality game, but the technology has the potential to be used in many other ways. Applied gravity could work to train athletes how to commit a movement to muscle memory, aid in physical therapy, help someone overcome a gravity-related fear such as falling or climbing, and a variety of applications that have yet to be explored.

“I think one of the most interesting pieces of feedback we received when conducting demos was the potential application for someone working in CGI,” says Nith. “Actors can sometimes have a hard time getting into character or embodying a bigger avatar in front of a green screen because it’s largely imagination. For instance, if someone playing the Hulk wanted to strike down their arm, they might really enjoy this backpack because it could potentially create a stronger sense of punch.”

In the future, the team would like to continue exploring other avenues where this technology can be implemented.

“In the past decade we have seen tremendous advances in VR, with graphics and interaction bringing it to a point where it is easy to feel visually immersed,” Lopes adds. “Yet, we think that unlocking the full potential of VR requires the physics to also ‘feel right.’ With JumpMod, we took a step toward uncovering how a relatively small wearable device might alter a large sensation, such as one’s sense of weight during a jump. Now we want to look deeper into how to create more physical sensations while keeping the resulting prototypes small, so that they will be compatible with everyday life.”

The team presented their work at the ACM CHI Conference on Human Factors in Computing Systems earlier this year but also took it on the road as a live demonstration to the ACM SIGGRAPH conference—a conference of around 15,000 attendees. While there, over 300 people had the opportunity to jump with the researcher’s device. The full paper details a breakdown of how JumpMod works, the hardware used, and the results from three different user studies.

Source: University of Chicago