Space & Physics
Need of the Hour – Evading the Kessler Syndrome
In 1978, Donald J. Kessler, an astrophysicist, predicted collisions between satellites can get out of hand as their population keeps increasing.

In 2009, the Iridium 33 and Kosmos 2251 satellites collided to produce as many as 2,000 debris fragments, spraying 10 cm wide pieces in every direction – at speeds faster than a bullet.
If any of these ever struck the ISS, orbiting closely, then all hell can break loose! Remember that scene in Gravity (2013) when Sandra Bullock’s character gets flung around? Well, it’s just one of several worse-case scenarios.
Even today, these space debris hover there, too close to be completely risk-free to the ISS.
The US’ operate a Space Surveillance Network that tracks these debris, along with more than 20,000 fragments. They comprise old rocket booster stages, junk satellites, missile components from anti-satellite launches.
However, very tiny pieces of fragments (<10 cm) can still be missed by ground radars. Space debris can include spent rocket stages, or defunct satellites drifting in space.
And a technical fix in orbital debris removing technology arose.
Last month February 18th saw the launch of the Active Debris Removal by Astroscale-Japan (or ADRAS-J) satellite from Rocket Lab’s launch station in New Zealand. ADRAS-J is yet to actually demonstrate debris removal, as it’s parked in a rendezvous orbit in preparation for the demonstration later this month.
In 2022, the UK stated Active Debris Removal (ADR) as being vital to their Plan for Space Sustainability to “become tomorrow’s norms in space operation”.
Space agencies across the world now issue commands for ‘collision avoidance maneuvers’ (CAM) when satellites cross within a certain radius.
In fact, the Indian Space Research Organization (ISRO) actually made public a trend showing the number of CAM commands issued rising every year. Such close-calls will only increase with the cumulative increase of satellites in orbit.
Here’s a plot from the European Space Agency’s (ESA) 2022 Space Environment Report.

A plot of the number of space debris against time. The legend indicates the various types of space debris (rocket, satellite parts etc.). Credit: ESA
But the problem is that – these satellite numbers are rising exponentially in such a short time – with mega-constellations entering center stage.
SpaceX launched the Starlink initiative, to demonstrate connectivity even in the remotest parts of the world.
However, they alone have 5,504 satellites out there to date, all at low-earth orbit – under 600 km, which is quite where the crowd of satellites are now. That’s about 58% of the 9,414 operational satellites out there. And this happened metaphorically overnight – in the past few years. SpaceX plans to operate some 42,000 satellites in a decade.
The fear is that unregulated growth of satellites – or even satellite litter that are defunct – can make what is known as the Kessler syndrome, a reality.
When Donald Kessler anticipated a chain reaction …
In 1978, Donald J. Kessler, an astrophysicist, predicted that collisions between satellites can trigger a domino effect of other satellite collisions above a certain threshold. Dubbed the Kessler syndrome, it’s a worst-case scenario possible in outer space, when earth’s orbit becomes impossible to thrive in or operate from.
To partly address the growing clutter of low-earth orbit satellites, the US’ Federal Communications Council (FCC) has put up legislation to have newly launched satellites deorbit 5 years after operations.
The irony is that the Kessler syndrome was foreseeable, except it was ignored by policymakers until they simply couldn’t.

Scientists building a satellite at RAL Space. Credit: UK STFC / Wikimedia
Western countries have taken some onus of responsibility into these space sustainability initiatives, simply because countries like the US own most of the satellite infrastructure operating in orbit.
From space shuttles, rockets, space planes and the lunar lander that brought Neil Armstrong and Edwin Aldrin to the moon, the Space Age heralded a brand new era for space technologies and research. But no space technology probably had more societal impact than the satellite.
Seen vital for development and infrastructure, satellites are now ubiquitous, manufactured not just by space agencies, but also by engineering labs in universities, private companies and start-ups across the world.
However, our costly endeavor to improve human lives are breeding new problems. And as a last resort, engineers are at it again to come up with technical fixes.
But weren’t the technical risks understood if Kessler expressed his concern in the 1970s?
Satellites, just like any technology, come with its set of benefits and risks. The benefits of satellites are obvious to many – phone connections, weather forecasting, banking, studying climate change, and the list goes on.
At the end of a satellite’s lifespan though, many just stay there, as defunct satellites.
Sure, there’s a ‘graveyard’ orbit where satellites can be made defunct after pushing them to a higher orbit to lay to rest forever. But not every defunct satellite is. In fact, 60% of all satellites are defunct. The operational satellites constitute a tiny minority.
Partly to do with this mess is a lack of priority. The Space Race played out during the peak of the Cold War when both the US and Soviets wanted to demonstrate technological superiority.
However, the outer orbit isn’t just a matter of mediating traffic or cleaning debris either.
Space militarization has raised fears. Much of the initial Space Race began with the US and Soviets fearing the other could surveil over their national boundaries. But the tensions have now made headlines, with the ongoing Russian invasion of Ukraine, with the US alleging that the Russians are developing a satellite that can drop nuclear weapons against the West. Building such a weapon would be violative of the 1967 Outer Space Treaty, in addition to several other regulations against weapons of mass destruction (WMDs).
There’s also anti-satellite launch systems firing repurposed ballistic missiles into space missiles. The US, Russia, China and India all possess this technology – and have the capacity to threaten orbital infrastructure – civilian or military. But the consequence of losing control over the weapons, is to hit the threshold dictated by the Kessler syndrome.
We’ll need to bear in mind that even technical fixes can’t fix design thinking. When planners aren’t held accountable, for their individual decisions – such avoidable doomsday disasters become a talking point.
Space & Physics
MIT unveils an ultra-efficient 5G receiver that may supercharge future smart devices
A key innovation lies in the chip’s clever use of a phenomenon called the Miller effect, which allows small capacitors to perform like larger ones

A team of MIT researchers has developed a groundbreaking wireless receiver that could transform the future of Internet of Things (IoT) devices by dramatically improving energy efficiency and resilience to signal interference.
Designed for use in compact, battery-powered smart gadgets—like health monitors, environmental sensors, and industrial trackers—the new chip consumes less than a milliwatt of power and is roughly 30 times more resistant to certain types of interference than conventional receivers.
“This receiver could help expand the capabilities of IoT gadgets,” said Soroush Araei, an electrical engineering graduate student at MIT and lead author of the study, in a media statement. “Devices could become smaller, last longer on a battery, and work more reliably in crowded wireless environments like factory floors or smart cities.”
The chip, recently unveiled at the IEEE Radio Frequency Integrated Circuits Symposium, stands out for its novel use of passive filtering and ultra-small capacitors controlled by tiny switches. These switches require far less power than those typically found in existing IoT receivers.
A key innovation lies in the chip’s clever use of a phenomenon called the Miller effect, which allows small capacitors to perform like larger ones. This means the receiver achieves necessary filtering without relying on bulky components, keeping the circuit size under 0.05 square millimeters.

Traditional IoT receivers rely on fixed-frequency filters to block interference, but next-generation 5G-compatible devices need to operate across wider frequency ranges. The MIT design meets this demand using an innovative on-chip switch-capacitor network that blocks unwanted harmonic interference early in the signal chain—before it gets amplified and digitized.
Another critical breakthrough is a technique called bootstrap clocking, which ensures the miniature switches operate correctly even at a low power supply of just 0.6 volts. This helps maintain reliability without adding complex circuitry or draining battery life.
The chip’s minimalist design—using fewer and smaller components—also reduces signal leakage and manufacturing costs, making it well-suited for mass production.
Looking ahead, the MIT team is exploring ways to run the receiver without any dedicated power source—possibly by harvesting ambient energy from nearby Wi-Fi or Bluetooth signals.
The research was conducted by Araei alongside Mohammad Barzgari, Haibo Yang, and senior author Professor Negar Reiskarimian of MIT’s Microsystems Technology Laboratories.
Society
Ahmedabad Plane Crash: The Science Behind Aircraft Take-Off -Understanding the Physics of Flight
Take-off is one of the most critical phases of flight, relying on the precise orchestration of aerodynamics, propulsion, and control systems. Here’s how it works:

On June 12, 2025, a tragic aviation accident struck Ahmedabad, India when a regional passenger aircraft, Air India flight A1-171, crashed during take-off at Sardar Vallabhbhai Patel International Airport. According to preliminary reports, the incident resulted in over 200 confirmed casualties, including both passengers and crew members, and several others are critically injured. The aviation community and scientific world now turn their eyes not just toward the cause but also toward understanding the complex science behind what should have been a routine take-off.
How Do Aircraft Take Off?
Take-off is one of the most critical phases of flight, relying on the precise orchestration of aerodynamics, propulsion, and control systems. Here’s how it works:
1. Lift and Thrust
To leave the ground, an aircraft must generate lift, a force that counters gravity. This is achieved through the unique shape of the wing, called an airfoil, which creates a pressure difference — higher pressure under the wing and lower pressure above — according to Bernoulli’s Principle and Newton’s Third Law.
Simultaneously, engines provide thrust, propelling the aircraft forward. Most commercial jets use turbofan engines, which accelerate air through turbines to generate power.
2. Critical Speeds
Before takeoff, pilots calculate critical speeds:
- V1 (Decision Speed): The last moment a takeoff can be safely aborted.
- Vr (Rotation Speed): The speed at which the pilot begins to lift the nose.
- V2 (Takeoff Safety Speed): The speed needed to climb safely even if one engine fails.
If anything disrupts this process — like bird strikes, engine failure, or runway obstructions — the results can be catastrophic.

Environmental and Mechanical Challenges
Factors like wind shear, runway surface condition, mechanical integrity, or pilot error can interfere with safe take-off. Investigators will be analyzing these very aspects in the Ahmedabad case.
The Bigger Picture
Take-off accounts for a small fraction of total flight time but is disproportionately associated with accidents — approximately 14% of all aviation accidents occur during take-off or initial climb.
Space & Physics
MIT claims breakthrough in simulating physics of squishy, elastic materials
In a series of experiments, the new solver demonstrated its ability to simulate a diverse array of elastic behaviors, ranging from bouncing geometric shapes to soft, squishy characters

Researchers at MIT claim to have unveiled a novel physics-based simulation method that significantly improves stability and accuracy when modeling elastic materials — a key development for industries spanning animation, engineering, and digital fabrication.
In a series of experiments, the new solver demonstrated its ability to simulate a diverse array of elastic behaviors, ranging from bouncing geometric shapes to soft, squishy characters. Crucially, it maintained important physical properties and remained stable over long periods of time — an area where many existing methods falter.
Other simulation techniques frequently struggled in tests: some became unstable and caused erratic behavior, while others introduced excessive damping that distorted the motion. In contrast, the new method preserved elasticity without compromising reliability.
“Because our method demonstrates more stability, it can give animators more reliability and confidence when simulating anything elastic, whether it’s something from the real world or even something completely imaginary,” Leticia Mattos Da Silva, a graduate student at MIT’s Department of Electrical Engineering and Computer Science, said in a media statement.
Their study, though not yet peer-reviewed or published, will be presented at the August proceedings of the SIGGRAPH conference in Vancouver, Canada.
While the solver does not prioritize speed as aggressively as some tools, it avoids the accuracy and robustness trade-offs often associated with faster methods. It also sidesteps the complexity of nonlinear solvers, which are commonly used in physics-based approaches but are often sensitive and prone to failure.
Looking ahead, the research team aims to reduce computational costs and broaden the solver’s applications. One promising direction is in engineering and fabrication, where accurate elastic simulations could enhance the design of real-world products such as garments, medical devices, and toys.
“We were able to revive an old class of integrators in our work. My guess is there are other examples where researchers can revisit a problem to find a hidden convexity structure that could offer a lot of advantages,” Mattos Da Silva added.
The study opens new possibilities not only for digital content creation but also for practical design fields that rely on predictive simulations of flexible materials.
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