It seems as though every week we see something that clearly shows we’re living in the future. The components we routinely incorporate into our projects would have seemed like science fiction only a few short years ago, but now we buy them online and have them shipped to us for pennies. And what can say we’ve arrived in the future more than off-the-shelf plasma thrusters for the DIY microsatellite market?
Although [Michael Bretti] does tell us that he plans to sell these thrusters eventually, they’re not quite ready for the market yet. The AIS-gPPT3-1C series that’s currently under testing is designed for the micro-est of satellites, the PocketQube, a format with a unit size only 5 cm on a side – an eighth the size of a 1U CubeSat. The thrusters are solid-fueled, with blocks of Teflon, PEEK, or Ultem that are ablated by a stream of plasma. The gaseous exhaust is accelerated and shaped by a magnetic nozzle that’s integrated right into the thruster. The thruster is mounted directly to a PCB containing the high-voltage supplies and control electronics to interface with the PocketQube’s systems. The 34-gram thrusters have enough fuel for perhaps 500 firings, although that and the specifics of performance are yet to be tested.
[Fossa Systems], a non-profit youth association based out of Madrid, is developing an open-source satellite set to launch in October 2019. The FossaSat-1 is sized at 5x5x5 cm, weighs 250g, and will provide free IoT connectivity by communicating LoRa RTTY signals through low-power RF-based LoRa modules. The satellite is powered by 28% efficient gallium arsenide TrisolX triple junction solar cells.
The satellite’s development and launch cost under EUR 30000, which is pretty remarkable for a cubesat — or a picosatellite, as the project is being dubbed. It has been working in the UHF Amateur Satellite band (435-438 MHz) and recently received an IARU frequency spectrum allocation for LoRa of 125kHz.
The satellite’s specs are almost as remarkable as the acronyms used to describe them. The design includes an onboard computer (OBC) based on an ATmega328P-AU microcontroller, an SX1278 transceiver for telecommunications, and an electric power system (EPS) based on three SPV1040 MPPT chips and the TC1262 LDO. The satellite also uses a TMP100 temperature sensor, an INA226 current and voltage sensor, a MAX6369 watchdog for single-event upset (SEU) protection, a TPS2553 for single-event latch-up (SEL) protection and various MOSFETs for the deployment of solar panels and antennas.
Up until this point the group has been tracking adoption of LoRa through the use of weather balloons. The cubesat project plans to test the new LoRa spread spectrum modulation using less than $5 worth of receivers. Ultimately with the goal of democratizing telecommunications worldwide.
The satellite is being built in a cleanroom at Rey Juan Carlos University and has undergone thermovacuum and vibration testing at the facility. The group has since developed an educational satellite development kit, which offers three main 40×40 mm boards that allow the addition of modifications. As their mission states, the group is looking to develop an open source project, so the code for the satellite is freely available on their GitHub.
There was a time when building your own satellite and having it placed into orbit would have been a wild dream. Now it is extremely possible, but still not trivial. A CubeSat is a very small satellite that can hitch a ride with a bigger satellite or get tossed out of a friendly space station. This week’s issue of The Orbital Index has a very good overview of what all is required. It also contains a great selection of links to get more information.
At first glance, it seems like it would be pretty simple. A computer, a battery, and some solar cells. Well, you probably want to hear back from it, so then you need a radio. Oh, and an antenna. But the antenna can’t stick out during launch so you need a way to deploy it. If you want the satellite to point somewhere, you’ll need things for that, too. Some CubeSats even have tiny thrusters to affect their orbit.
While recent commercial competition has dropped the cost of reaching orbit to a point that many would have deemed impossible just a decade ago, it’s still incredibly expensive. We’ve moved on from the days where space was solely the domain of world superpowers into an era where multi-billion dollar companies can join on on the fun, but the technological leaps required to reduce it much further are still largely relegated to the drawing board. For the time being, thing’s are as good as they’re going to get.
If we can’t count on the per pound cost of an orbital launch to keep dropping over the next few years, the next best option would logically be to design spacecraft that are smaller and lighter. Thankfully, that part is fairly easy. The smartphone revolution means we can already pack an incredible amount sensors and processing power into something that can fit in the palm of your hand. But there’s a catch: the Tsiolkovsky rocket equation.
Often referred to as simply the “rocket equation”, it allows you to calculate (among other things) the ratio of a vehicle’s useful cargo to its total mass. For an orbital rocket, this figure is very small. Even with a modern launcher like the Falcon 9, the payload makes up less than 5% of the liftoff weight. In other words, the laws of physics demand that orbital rockets are huge.
Unfortunately, the cost of operating such a rocket doesn’t scale with how much mass it’s carrying. No matter how light the payload is, SpaceX is going to want around $60,000,000 USD to launch the Falcon 9. But what if you packed it full of dozens, or even hundreds, of smaller satellites? If they all belong to the same operator, then it’s an extremely cost-effective way to fly. On the other hand, if all those “passengers” belong to different groups that split the cost of the launch, each individual operator could be looking at a hundredfold price reduction.
Back in April we reported on the successful launch of the SpaceX Falcon 9 rocket to the International Space Station which carried, along with supplies and experiments for the orbiting outpost, the RemoveDEBRIS spacecraft. Developed by the University of Surrey, RemoveDEBRIS was designed as the world’s first practical demonstration of what’s known as Active Debris Removal (ADR) technology. It included not only a number of different technologies for ensnaring nearby objects, it even brought along deployable targets to use them on.
Orbital debris (often referred to simply as “space junk”) is a serious threat to all space-faring nations, and has become even more pressing of a concern as the cost of orbital launches have dropped precipitously over the last few years, accelerating number and frequency of new objects entering orbit. The results of these first of their kind tests have therefore been hotly anticipated, as the technology to actively remove debris from Low Earth orbit (LEO) is seen by many in the industry to be a key element of expanding access to space for commercial purposes.
Every year at Supercon there is a critical mass of awesome people, and last year Sophi Kravitz was able to sneak away from the festivities for this interview with Katherine Scott. Kat was a judge for the 2017 Hackaday Prize. She specializes in computer vision, robotics, and manufacturing and was the image analytics team lead at Planet Labs when this interview was filmed.
You’re going to chuckle at the beginning of the video as Kat and Sophi recount the kind of highjinks going on at the con. In the hardware hacking area there were impromptu experiments in melting aluminum with gallium, and one of the afternoon’s organized workshop combined wood and high voltage to create lichtenberg figures. Does anyone else smell burning? Don’t forget to grab your 2018 Hackaday Superconference tickets and join in the fun this year!
Below you’ll find the interview which dives into Kat’s work with satellite imaging.
Space elevators belong to that class of technology that we all want to see become a reality within our lifetimes, but deep-down doubt we’ll ever get to witness firsthand. Like cold fusion, or faster than light travel, we understand the principles that should make these concepts possible, but they’re so far beyond our technical understanding that they might as well be fantasy.
Except, maybe not. When Japan Aerospace Exploration Agency (JAXA) launches their seventh Kounotori H-II Transfer Vehicle towards the International Space Station, riding along with the experiments and supplies for the astronauts, will be a very special pair of CubeSats. They make up the world’s first practical test of space elevator technology, and with any luck, will be one of many small steps that precedes the giant leap which access to space at a fraction of the cost will be.
Of course, they won’t be testing a fully functional space elevator; even the most aggressive of timelines put us a few decades out from that. This will simply be a small scale test of some of the concepts that are central to building a space elevator, as we need to learn to crawl before we can walk. But even if we aren’t around to see the first practical space elevator make it to the top, at least we can say we were there on the ground floor.