Satellite internet used to be a woeful thing. Early networks relied on satellites in geostationary orbits, with high latency and minimal bandwidth keeping user demand low. That was until Starlink came along, and provided high-speed, low-latency internet access using a fleet of thousands of satellites in Low Earth orbit.
Much of the reporting around climate change focuses on carbon dioxide. It’s public enemy number one when it comes to gases that warm the atmosphere, as a primary byproduct of fossil fuel combustion.
It’s not the only greenhouse gas out there, though. Methane itself is a particularly potent pollutant, and one that is being emitted in altogether excessive amounts. Satellites are now on the hunt for methane emissions in an attempt to save the world from this odorless, colorless gas.
Hanging around in earth orbit is like walking into the middle of a Wild West gunfight — bullets are flying around everywhere, and even though none are purposefully aimed at you, one might have your name on it. Many of these bullets are artificial satellites that are actively controlled and monitored, but we also find dead satellites, remnants of satellites, discarded rocket stages, tools lost during spacewalks, and even flecks of paint and rust, much of it zipping around at multiple kilometers per second without any guidance.
While removing this space debris directly would be ideal, the reality is that any spacecraft and any spacesuit that has to spend time in orbit needs to be capable of sustaining at least some hits by space debris impacting it.
Orbital Mechanics
That it’s easy to create new debris should come as no surprise to anyone. What may take a bit more imagination is just how long it can take for this debris to make its way towards earth’s atmosphere, where it will uneventfully burn up. Everything in orbit is falling toward the earth, but its tangential velocity keeps it from hitting — like a marble spinning around the hole in a funnel. Drag from the planet’s atmosphere is the friction that eventually slows the object down, and where it orbits in the planet’s atmosphere determines how long this descent will take. Continue reading “Orbital Safety: The Challenges Of Surviving Space Junk”→
On a dark night in 2006 I was bicycle commuting to my office, oblivious to the countless man made objects orbiting in the sky above me at thousands of miles per hour. My attention was instead focused on a northbound car speeding through a freeway underpass at dozens of miles per hour, oblivious to my southbound headlamp. The car swerved into the left turn lane to get to the freeway on-ramp. The problem? I was only a few feet from crossing the entrance to that very on-ramp! As the car rushed through their left turn I was presented with a split second decision: slow, and possibly stop in the middle of the on-ramp, or just go for it and hope for the best.
In Blue: Terrified cyclist. In Red: A speeding car careening around a corner without slowing down.
By law I had the right of way. But this was no time to start discussing right of way with the driver of the vehicle that threatened to turn me into a dark spot on the road. I followed my gut instinct, and my legs burned in compliance as I sped across that on-ramp entrance with all my might. The oncoming car missed my rear wheel by mere feet! What could have ended in disaster and possibly even death had resulted in a near miss.
Terrestrial vehicles generally have laws and regulations that specify and enforce proper behavior. I had every right to expect the oncoming car be observant of their surroundings or to at least slow to a normal speed before making that turn. In contrast, traffic control in Earth orbit conjures up thoughts of bargain-crazed shoppers packed into a big box store on Black Friday.
So is spacecraft traffic in orbit really a free-for-all? If there were stringent rules, how can they be enforced? Before we explore the answers to those questions, let’s examine the problem we’re here to discuss: stuff in space running into other stuff in space.
Want to build your own CubeSat but have been put off by the price? There may be a solution in the works — [RG Sat] has challenged himself to design and build one for less than $1,000. (Video, embedded below.)
He begins by doing a survey of available low-cost options in the first video, and finds there isn’t a complete package for less than $10,000. By the time you added all necessary “options”, the final tally would probably be well over $20,000.
His idea isn’t just a pipe dream, either. In the the fifteen months since he began the project, [RG Sat] has designed and built the avionics and electrical power system circuit boards, and is currently testing his sun tracker design. Software is written in Rust, just because he wants to learn something new. You can check out the hardware and software design files on the project’s GitHub repositories, if you are inclined to build one yourself.
[RG Sat] lays out a compelling case, but we wonder if there’s a major gotcha lurking in the dark somewhere. In fact, [RG Sat] himself asks the question, “where do these high costs come from?” Our first instinct is to point the finger at qualifying parts for space and/or testing. But if you don’t care about satellite longevity or failure rates, then maybe [RG Sat] is onto something here.
Stepping back and looking at the big picture, however, the price of a CubeSat can be a drop in the bucket when compared to the launch costs, unless you’ve got a free ride. Is hardware the best place to focus cost reduction efforts? Regardless, [RG Sat]’s project is bound to provide interesting and useful results whether he succeeds in his goal or confirms that indeed you need $10,000 to build a CubeSat. We’ll be following his progress with interest.
South Korea’s space program achieved another milestone yesterday with the launch of the first Compact Advanced Satellite 500 (CAS500) in a planned series of five vehicles. A second-generation Russian Soyuz 2.1a lifted the Korean-made CAS500-1 from historic Baikonur Cosmodrome in southern Kazakhstan and successfully placed it into a 500 km sun-synchronous orbit, inclined by 97.7 degrees or 15 orbits/day. Living up to its reputation as a workhorse, the Soyuz then proceeded to deposit multiple other satellites into 600 km and 550 km orbits. The satellite is pretty substantial, being 2.9 m tall and 1.9 m diameter and topping the scales at 500 kg. (Don’t be confused, like we were, by this Wikipedia article that says it is a 1.3 kg CubeSat.)
South Korea already has over a dozen satellites in orbit, and the CAS500 adds a modular space platform to the mix. It was designed by the Korea Aerospace Research Institute (KARI) to provide a core backbone which can be easily adapted to other missions, not unlike a car manufacturer that sells several different models all based on the same underlying chassis. Another down-to-earth goal of the CAS500 program was to foster the transfer of core technologies from state-owned KARI to private industry. We wonder how such figures are calculated, but reportedly 91.3% of CAS500-1 was made in Korea. Subsequent flights will further involve local services and industry.
The purpose of the first two satellites is to provide images to the private sector, for example, online mapping and navigation platforms. How popular this will be is yet to be determined — as one local newspaper notes, the 2 meter image resolution (50 cm in monochrome) pales in comparison to Google’s advertised 15 cm resolution. The next three satellites will focus on space science imagery.
The Soyuz launch is shown below, and this short video clip from KARI shows a nice animation of the satellite. Try not to cringe at the simulated whooshing sound as two satellites pass each other in the vacuum of space — turn down the volume if you need to.
When you look back on the development history of any technology, it’s clear that the successful products eventually reach an inflection point, the boundary between when it was a niche product and when it seems everyone has one. Take 3D-printers, for instance; for years you needed to build one if you wanted one, but now you can buy them in the grocery store.
It seems like we might be getting closer to the day when satellites reach a similar inflection point. What was once the province of nations with deep pockets and military muscles to flex has become far more approachable to those of more modest means. While launching satellites is still prohibitive and will probably remain so for years to come, building them has come way, way down the curve lately, such that amateur radio operators have constellations of satellites at their disposal, small companies are looking seriously at what satellites can offer, and even STEM programs are starting to get students involved in satellite engineering.
Michael Bretti is on the leading edge of the trend toward making satellites more DIY friendly. He formed Applied Ion Systems to address one of the main problems nano-satellites face: propulsion. He is currently working on a range of open-source plasma thrusters for PocketQube satellites, a format that’s an eighth the size of the popular CubeSat format. His solid-fuel electric thrusters are intended to help these diminutive satellites keep station and stay in orbit longer than their propulsion-less cousins. And if all goes well, someday you’ll be able to buy them off-the-shelf.
Join us for the Hack Chat as Michael discusses the design of plasma thrusters, the details of his latest testing, and the challenges of creating something that needs to work in space.
Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.
