Voices Of XDA: Orbiting The Earth With Android
Editor’s note: This week’s feature has been written by forum member RowHanSolo and takes a look at the exciting prospect of launching satellites fitted with little more than an Android phone as an onboard computer. From a university to NASA, multiple projects like this have launched!
Technology is an ever-growing industry, regardless of which corner you look at. However, each area of technology has its limitations on what it can do and how far it can expand. For satellite technology, that limitation is space. Now when I say space I don’t mean the vast void of the universe, I mean the orbital space around our planet.
We rely on the array of satellites shooting around our planet for much of what we do. No doubt, every one of you has a mobile phone or tablet that requires these satellites; whether it be for GPS navigation, messaging or even internet. There are 6 billion mobile phones currently active in the world; that’s certainly a lot of satellite coverage for mobile phones alone, never mind the satellites we use for other purposes. This leads to about 1100 active satellites, both private and public, and over 2500 decommissioned satellites all orbiting the Earth. Now that is a lot of space. So how do we fix this? The answer may come from one of the causes of satellite crowding and, as I’ve said, you all most likely own one: mobile phones.
You see, as the mobile phone industry has grown, the hardware and software incorporated into each device has expanded. Current mobiles all now contain magnetometers, accelerometers, gyroscopes, cameras, a power supply and, of course, a processor; all the equipment necessary for a basic satellite.
A couple of teams of researchers in the scientific community took advantage of this and started two projects; NASA’s PhoneSat and The University of Surrey space research centre’s (SSC), in association with SSTL (Surrey Satellite Technology Ltd.), STRaND-1.
STRanD-1 is a 3U CubeSat that launched in 2013. Despite being launched two years ago it is still functioning, despite only being powered by a Google Nexus One and still running Android OS.
Not only was STRaND-1 the first nano-satellite to be run by an off-the-shelf smartphone, it also picked up a number of other firsts in the process. Alongside the equipment provided by the smartphone, such as a camera, accelerometers and radio links, the satellite also has two different types of experimental propulsion systems; a WARP DRIVE (Water Alcohol Resistojet Propulsion Deorbit Reentry Velocity Experiment)* and electric Pulsed Plasma Thrusters (PPTs). Both of these propulsion systems are the first to be used on a nano-satellite. The satellite is also flying with amateur radion 9600 bps AX.25 packet radio downlink on 437.568 MHz to allow for effective communication and tracking of the satellite and a 3D printed part, believed to be the first used in space. The telemetry information and tracking is monitored by AMSAT-UK.
*The WARP DRIVE works by firing jets of water alcohol through a 0.2mm hole, providing more thrust than similar sized propulsion systems whilst maintaining a specific impulse of the same standard.
At this point in time the project is in Phase 2. This means that now all control of the satellite is being run by the Nexus One at its heart. Furthermore, the phone is also running four additional apps designed and made by the public. While still under construction, the team at SSC ran a FaceBook competition to find these apps, and these were the four winning apps:
iTESA – This app utilizes the phone’s magnetometer, usually used to determine the orientation of the phone, to measure and record the magnetic field around the phone. This data could be used as proof of principle for principles such as Alfven waves (Magnetic oscillations in the upper atmosphere).
The STRaND Data app – Installed on the satellite is a second camera, external to the phone, that faces the screen. The app displays the telemetry information of the satellite on the phone’s screen in graphical representations. Not only will this prove that a standard smartphone screen is durable enough to withstand the harshness of space, but will also allow us to interpret trends from new graphical telemetry.
The 360 app – Using a combination of the smartphone camera and the other equipment on the satellite, this app determines the position of the satellite over Earth. Images can also be requested to be taken from the satellite via an online site and then shown on a map of where they were taken (http://www.360app.co.uk/).
Scream in Space – This app is set to test the popular theory from the Sci-Fi film Alien (1979) that in space, no one can hear you scream. The public are encouraged to record themselves screaming in many different ways and upload it to a website, where the most popular videos will then be uploaded to the satellite and played through the phone’s speakers. The phone’s mic will then attempt to re-record the scream.
Unlike STRaND-1, PhoneSat was not equipped with any propulsion systems and as such, the mission was much shorter. However, the PhoneSat mission was comprised of three satellites. The orbits of the satellites decayed after about one week, but this was enough time to achieve NASA’s mission objectives. The main objective of the PhoneSat mission was simply to prove that a satellite built from Commercial Off-The-Shelf (COTS) products could survive and operate in the harshness of space. Of the three satellites that were launched, there were two different models, Graham and Bell. Two Graham models and one Bell were launched into orbit on the maiden voyage of the Antares launch vehicle on April 21st 2013.
Graham is the PhoneSat 1.0 base model. Like STRaND-1, it is powered by a Nexus One running Google’s Android 2.3.3. As well as the phone, the satellite contains an accelerometer, magnetometer and a StenSat radio at 437.425 MHz. The radio transmissions sent small data packets containing images taken from the smartphone camera to amature radio operaters and tracking stations around the world, where they were then sent to the NASA Ames Research Centre. Here they stitched the data packets back into complete images.
Bell is the PhoneSat 1.0 (Graham) model but with one addition, an Iridium transceiver mounted on one end. The purpose of the Iridium experiment was to send data packet to the Iridium satellite constellation** which were then sent via email to NASA.
**The Iridium satellite constellation is a satellite constellation owned by Iridium Communications and is used to send data and voice coverage to pagers and satellite phones on the Earth’s surface.
NASA are currently working on a new beta model of the PhoneSat. Alexander is the beta PhoneSat 2.0. On top of the suite of equipment carried on Graham, Alexander has some additions and improvements. Firstly, Alexander carries a Nexus S, as opposed to the Nexus One, running Android 2.3.3. It also comes with a router, solar panels to charge the phone battery and magnetic torquers*** to reduce the spin rate of the satellite to no less than 5dps (degrees per second). The mission objectives of Alexander, when launched, will be to turn on, charge its batteries and send sensor data.
***Magnetic torquers work by inducing a magnetic field that interacts with the ambient magnetic field, creating forces on the torque rod that produce a torque.
Now, both of these projects were made with, now outdated, Android phones. There have been many advancements in Android technology over just a couple of years; improved magnetometers, more efficient batteries and more powerful processors, higher resolution cameras and much more. The satellites we could build out of these more advanced devices can be incredible. And if you’re thinking ‘but what about the price tag?’ bear in mind that the PhoneSat 1.0 cost just $3,500 to make by being built out of COTS. Now this is a quite bit of money but compared to the average cost of a normal satellite, around 200 million US dollars, it’s mere pennies and something that could easily be financed by a few like-minded enthusiasts.
In a world where technology appears to be getting bigger and better, maybe the answer to some of the problems this causes is to utilize the smaller ‘commercial’ advances.
For more information on the STRaND-1 project head over to here,
For telemetry information about the STRaND-1 visit this site,
Online live tracking of STRaND-1 is available here,
More information on the PhoneSat project can be found here.
This article was part of our series “Voices of XDA”. The new articles you will start to see under “Voices” are entirely thought of and written by you, the members of XDA. If you have an idea for an article you would like to write, you can find more information here and apply here.