Pushing the Limits of Satellite Technology

They hitched a hike on the Insight Mars lander, separating from the spacecraft to fly on their own. Before long they had gone farther than any previous CubeSat craft. They were the Mars Cube One (MarCO) satellites, nicknamed Wall-E and Eve. Although they finished their mission, the breakthroughs in minimalistic satellite technology remain. Among them, traveling the farthest distance for a Yocto Project Linux-based computer, a distribution that we are all too familiar with in the embedded space. Closer to home or farther into space, the satellite technology continues to evolve, from small low-orbit satellites to cubesats, and Wind River is there to enable this revolution.

Photo copyright: NASA/JPL-Caltech

Minimalism in Space

The first US Weather Satellite, TIROS I, weighted 270 pounds. That made most people associate the word “satellite” with either a moon, a sputnik, or a modern rig with rocket motors, solar panels, and antennae. This could not be further away from the truth. Since 1998, over 2000 satellites have been launched that a person could hold in their hand. These are CubeSats – satellites a bit larger than a softball that can be developed a fraction of the cost and are becoming common research tools.

The Mars InSight CubeSats mentioned earlier were no bigger than a lunch-box – 36 x 24 x 11 cm (14in x 9.5in x 4in, or “6U” sized). These were the first two cubesats to go beyond Earth orbit to another planet. They served as communications relays for Mars InSight as she went through Entry, Descent, and Landing on the Red Planet. These two 14-pound miniature satellites hitched a ride on InSight’s Atlas V launch vehicle, and were deployed by spring-loaded carriers after the upper-stage released InSIght on its course to Mars.

CubeSats are not just the current sweethearts of government agencies. With costs estimated between $8,000.00 and $11,000.00, and NASA projects creating affordable ways to get them into space, 1U and 3U CubeSats are becoming the research pride of universities as well. Venture Class Launch Services (NASA) contracts with 3 companies for Cubesat/nanosat/smallsat launch capability. In addition, CubeSats can hitch rides on larger rockets aboard spring-loaded launchers call “Pea Pods”.

CubeSat Launch Initiative: Electron will carry 10 cubesates as part of ELaNa program – Educational Launch of NanoSatellites – which has selected about 150 cubesats for launching, though about 10 launches starting this year (2019). As part of the CSLI, ELaNa provides launch opportunities for educational programs (High Schools, Universities, etc.) that might not otherwise be able to afford to launch satellites on their own. CSLI is part of the Venture Class Launch Initiative, part of the overall Launch Services Program for NASA. LSP itself covers everything from larger rockets (Delta II, Atlas V, etc.) on which CubeSat “pea-pods” can be piggybacked, through the VCSL NASA enables programs like CSLI and ELaNa focusing on launch systems designed just for these tiny satellites. (Rocket Lab USA Inc. of Los Angeles, builds the $6.9 million “Electron” rocket in Long Beach CA. The 3-D printed engines take about 24 hours to print, and are propelled by RP1 and Liquid Oxygen fuel.) CSLI and ELaNa currently have contracts with three companies to provide launch capabilities - Firefly Space Systems Inc. of Cedar Park, Texas; Virgin Galactic LLC of Long Beach, California, via Virgin OneLaunch; and Rocket Lab USA Inc. of Los Angeles, via “Electron” rocket, launched from NZ.

Technological Breath

Size: The cube-shaped satellites being manifested as part of these two venture class demonstration launches are approximately four inches long, have a volume of about one quart and weigh about 3 pounds. The standard dimension of a CubeSat is 1 unit or 1U, which is equal to 10x10x10 cm, and CubeSats can be up to 6U in total size. The CubeSats on NASA’s venture class missions are 3U and 6U in size, providing more room for science and instruments. Other small satellites may be closer to 1m x 1m x 1m — but still very small compared to a traditional telecommunications satellites.

Computers: CubeSats come with a variety of modern miniaturized computers, many are similar to BeagleBoard or Pine64. These credit-card sized computers can feature multiple ARM cores and memory sizes in excess of 2 GB of RAM and a micro-SD slot for Flash storage. CubeSats tend to be more conservative, featuring similar ARM7 architectures with memories of 256MB of RAM and 500MB of ROM space. Considering Mars Exploration Rovers Opportunity and Spirit used 32MB of RAM for the OS, and 3MB of EEPROM, CubeSats are the perfect platform for the VxWorks.

Operating Systems: The boards powering the Mars InSight CubeSats ran Yocto Project based Linux on a Cortex-A8 DM3730 SoC from Texas Instruments. This was a new approach and it pushed the limits of COTS hardware and open source components. At the same time, many of the traditional challenges associated with space programs still hold true. Closer to home, new constellations of satellites are preparing to provide connectivity for IoT solutions. Deployed in the Low Earth Orbit as opposed to the traditional Geosynchronous Orbit, these satellites surpass previous signal issues, but are bound by the same strict security requirements dictated by telecommunication use cases.

VxWorks provides deterministic hard real-time performance, enabling applications such as asset tracking, agriculture, and fleet management to utilize the full performance capabilities of the CubeSat computer platform. VxWorks is also scalable and highly configurable, enabling system designers to configure the software footprint to match the available resources of the underlying COTS hardware platform. VxWorks also provides extensive security capabilities to safeguard the systems, connections, data and intellectual property against threats. Testing and simulation technologies play a very important role as well in managing quality and lifecycle cost.

Cubesat/nanosat/smallsat: The New Space Race

New business models and significant venture funding are now finding their way to commercial space applications. Approximately two dozen startups, including Astranis, Astrocast, and Swarm, have entered this new space race in an effort to increase the value proposition of satellite-connected IoT solutions. These startups are joining established satellite communications companies and are focused on reducing the costs of creating new communication networks at a significantly lower deployment and solution costs.

Wind River has worked with Astranis to enable these new communication use cases. Astranis is building satellites the size of a washer/dryer that are capable of delivering broadband internet services to telecommunications services around the globe. Their business case highlights especially areas where broadband internet isn't widely available or unavailable at all. Over half of the world doesn't have access to the internet - and satellites might play a major role in connecting them.

Image copyright: Astranis

New satellite technology is powering a revolution on Earth and beyond. Either from more than 2 million miles beyond Mars or from the low Earth orbit, it is redefining the connectivity landscape.

Images and videos courtesy of NASA, NASA/JPL, and NASA/JPL-Caltech

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