space debris

13 Articles

Photo manipulation of Skynet-1A hovering a planet

Britain’s Oldest Satellite On The Move: A Space Curiosity

November 11, 2024 by 7 Comments

Space and mystery always spark our curiosity, so when we stumbled upon the story of Skynet-1A, Britain’s first communication satellite from 1969, we knew it was worth exploring. The BBC recently highlighted its unexpected movement across the sky – you can check out their full coverage here. The idea that this half-century-old hunk of metal mysteriously shifted orbits leaves us with more questions than answers. Who moved Skynet-1A, and why?

Launched just months after the Apollo 11 Moon landing, Skynet-1A stood as a symbol of Cold War innovation, initially placed above East Africa to support British military communications. But unlike the silent drift of inactive satellites heading naturally eastward, Skynet-1A defied orbital norms, popping up halfway across the globe above the Americas. This wasn’t mere chance; someone or something had made it fire its thrusters, likely in the mid-1970s.

Experts like Dr. Stuart Eves and UCL’s Rachel Hill suggest the possibility of control being temporarily transferred to the US, particularly during maintenance periods at the UK’s RAF Oakhanger. Still, the specifics remain buried in lost records and decades-old international collaborations. Skynet-1A’s journey serves as a stark reminder of the persistent challenges in space and the gaps in our historical data.

Looking for more space oddities? Hackaday has some interesting articles on space debris. You can read the original BBC article here.

Flirting With Kessler: Why Space Debris Physics Make It Such An Orbital Pain

November 5, 2024 by 37 Comments

Picture in your mind a big parking lot with 131 million cars on it. Now imagine that they are spread out over the entire Earth’s inhabited areas. Although still a large number, it is absolutely dwarfed by the approximately 1.47 billion cars registered and in use today, with room to spare for houses, parks and much more. The 131 million represents the total number of known and estimated space debris objects in Earth orbit sized 1 mm and up, as per the European Space Agency. This comes on top of the approximately 13,200 satellites still in Earth orbit of which 10,200 are still functional.

Now imagine that most of these 131 million cars of earlier are sized 10 cm or smaller. Spaced out across the Earth’s entire surface you’d not be able to see more than at most one. Above the Earth’s surface there are many orbital planes and no pesky oceans to prevent millimeter and centimeter-sized cars from being spaced out there. This gives a rough idea of just how incredibly empty Earth’s orbital planes are and why from the International Space Station you rarely notice any such space debris until a small bit slams into a solar panel or something equally not amusing.

Cleaning up space debris seems rather unnecessary in this perspective, except that even the tiniest chunk travels at orbital velocities of multiple kilometers per second with kinetic energy to spare. Hence your task: to chase down sub-10 cm debris in hundreds of kilometers of mostly empty orbital planes as it zips along with destructive intent. Surely this cannot be so difficult with lasers on the ISS or something?

Continue reading “Flirting With Kessler: Why Space Debris Physics Make It Such An Orbital Pain” →

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Hackaday Links: July 7, 2024

July 7, 2024 by 7 Comments

Begun, the Spectrum Wars have. First, it was AM radio getting the shaft (last item) and being yanked out of cars for the supposed impossibility of peaceful coexistence with rolling broadband EMI generators EVs. That battle has gone back and forth for the last year or two here in the US, with lawmakers even getting involved at one point (first item) by threatening legislation to make terrestrial AM radio available in every car sold. We’re honestly not sure where it stands now in the US, but now the Swiss seem to be entering the fray a little up the dial by turning off all their analog FM broadcasts at the end of the year. This doesn’t seem to be related to interference — after all, no static at all — but more from the standpoint of reclaiming spectrum that’s no longer turning a profit. There are apparently very few analog FM receivers in use in Switzerland anymore, with everyone having switched to DAB+ or streaming to get their music fix, and keeping FM transmitters on the air isn’t cheap, so the numbers are just stacked against the analog stations. It’s hard to say if this is a portent of things to come in other parts of the world, but it certainly doesn’t bode well for the overall health of terrestrial broadcasting. “First they came for AM radio, and I did nothing because I’m not old enough to listen to AM radio. But then they came for analog FM radio, and when I lost my album-oriented classic rock station, I realized that I’m actually old enough for AM.”

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Upper stage of a Japanese H-2A rocket which has been in orbit since 2009. It's one of the largest pieces of orbital debris. (Credit: Astroscale)

Astroscale’s ADRAS-J Satellite Takes Up-Close Photo Of Discarded Rocket Stage

June 18, 2024 by 23 Comments

Although there is a lot of space in Earth orbit, there are also some seriously big man-made objects in those orbits, some of which have been there for decades. As part of efforts to remove at least some of this debris from orbit, Astroscale’s ADRAS-J (“Active Debris Removal by Astroscale-Japan”) satellite has been partaking in JAXA’s Commercial Removal of Space Debris Demonstration (CRD2). After ADRAS-J was launched by a Rocket Lab Electron rocket on February 18, it’s been moving closer to its target, with June 14th seeing an approach by roughly 50 meters, allowing for an unprecedented photo to be made of the H-2A stage in orbit. This upper stage of a Japanese H-2A rocket originally launched the GOSAT Earth observation satellite into orbit back in 2009.

The challenges with this kind of approach is that the orbital debris does not actively broadcast its location, ergo it requires a combination of on-ground and on-satellite tracking to match the orbital trajectory for a safe approach. Here ADRAS-J uses what is called Model Matching Navigation, which uses known visual information to compare it with captured images, to use these to estimate the relative distance to the target.

Although the goal of ADRAS-J is only to study the target from as closely as possible, the next phase in the CRD2 program would involve actively deorbiting this upper stage, with phase start projected to commence in 2026.

Thanks to [Stephen Walters] for the tip.

Continue reading “Astroscale’s ADRAS-J Satellite Takes Up-Close Photo Of Discarded Rocket Stage” →

IRCB S73-7 Satellite Found After Going Untracked For 25 Years

May 12, 2024 by 26 Comments

When the United States launched the KH-9 Hexagon spy satellite into orbit atop a Titan IIID rocket in 1974, it brought a calibration target along for the ride: the Infra-Red Calibration Balloon (IRCB) S73-7. This 66 cm (26 inch) diameter inflatable satellite was ejected by the KH-9, but failed to inflate into its intended configuration and became yet another piece of space junk. Initially it was being tracked in the 1970s, but vanished until briefly reappearing in the 1990s. Now it’s popped up again, twenty-five years later.

As noted by [Jonathan McDowell] who tripped over S73-7 in recent debris tracking data, it’s quite possible that it had been tracked before, but hidden in the noise as it is not an easy target to track. Since it’s not a big metallic object with a large radar cross-section, it’s among the more difficult signals to reliably pick out of the noise. As can be seen in [Jonathan]’s debris tracking table, this is hardly a unique situation, with many lost (XO) entries. This always raises the exciting question of whether a piece of debris has had its orbit decayed to where it burned up, ended up colliding with other debris/working satellite or simply has gone dark.

For now we know where S73-7 is, and as long as its orbit remains stable we can predict where it’ll be, but it highlights the difficulty of keeping track of the around 20,000 objects in Earth orbit, with disastrous consequences if we get it wrong.

Five Years On, Where Is Starman And Where Will He Go?

February 9, 2023 by 55 Comments

On 6 February 2018, a Tesla Roadster was launched as the mass simulator on the first ever Falcon Heavy launch — putting for the first time ever a car on a Mars-crossing orbit. While undoubtedly a bit of a stunt, the onboard cameras provided an amazing view of our planet Earth as the Starman dummy in the Roadster slowly drifted away from that blue marble, presumably never to be seen again.

This “never” is the point that researchers at the University of Toronto would like to clarify in a paper published after the launch titled The Random Walk of Cars and Their Collision Probabilities with Planets. Using N-body simulations, they come to the conclusion that there’s a 22%, 12%, and 12% chance of the Roadster impacting the Earth, Venus, and the Sun, respectively. But don’t get too excited, it’s not due to happen for a few million years, so it isn’t something any of us will be around to see.

As the Where Is Starman? website shows, the Roadster never reached escape velocity from the Sun’s gravity, meaning that it’s still zipping around in an orbit around our day star. Exposed to the harsh UV and other radiation, it’s likely that very little is left at this point of the Tesla, or Starman himself. Even so, scientists to this day are feeling less than amused by what they see as essentially littering, adding to the discarded rocket stages, dead satellites and other debris that occasionally makes it into the news when it smashes into the Moon, or threatens the ISS.

Quick Reaction Saves ESA Space Telescope

October 22, 2021 by 5 Comments

Once launched, most spacecraft are out of reach of any upgrades or repairs. Mission critical problems must be solved with whatever’s still working on board, and sometimes there’s very little time. Recently ESA’s INTEGRAL team was confronted with a ruthlessly ticking three hour deadline to save the mission.

European Space Agency INTErnational Gamma-Ray Astrophysics Laboratory is one of many space telescopes currently in orbit. Launched in 2002, it has long surpassed its original designed lifespan of  two or three years, but nothing lasts forever. A failed reaction wheel caused the spacecraft to tumble out of control and its automatic emergency recovery procedures didn’t work. Later it was determined those procedures were dependent on the thrusters, which themselves failed in the summer of 2020. (Another mission-saving hack which the team had shared earlier.)

With solar panels no longer pointed at the sun, battery power became the critical constraint. Hampering this time-critical recovery effort was the fact that antenna on a tumbling spacecraft could only make intermittent radio contact. But there was enough control to shut down additional systems for a few more hours on battery, and enough telemetry so the team could understand what had happened. Control was regained using remaining reaction wheels.

INTEGRAL has since returned to work, but this won’t be the last crisis to face an aging space telescope. In the near future, its automatic emergency recovery procedures will be updated to reflect what the team has learned. Long term, ESA did their part to minimize space debris. Before the big heavy telescope lost its thrusters, it had already been guided onto a path which will reenter the atmosphere sometime around 2029. Between now and then, a very capable and fast-reacting operations team will keep INTEGRAL doing science for as long as possible.