Small satellites, miniaturized satellites, or smallsats, are satellites of low mass and size, usually under 500 kg (1,100 lb). Like your mobiles, satellites are also getting smaller and better. Small satellites are those satellites that are just about the size of your shoe box. But, they can do almost everything a conventional satellite does, and that too at a fraction of the cost. Which is why everybody — from government organizations and start-ups to educational institutes — is scrambling to get a piece of the small-sat pie.
The big bang theory of small sats can be attributed to fast-changing technology trends cutting down gestation periods. The industry is responding to the subsequent profit vulnerability by making smaller spacecrafts quickly, deploying them even more swiftly and getting data from them rapidly.
While all such satellites can be referred to as “small”, different classifications are used to categorize them based on mass. Satellites can be built small to reduce the large economic cost of launch vehicles and the costs associated with construction. Miniature satellites, especially in large numbers, may be more useful than fewer, larger ones for some purposes – for example, gathering of scientific data and radio relay. Technical challenges in the construction of small satellites may include the lack of sufficient power storage or of room for a propulsion system.
To be clear, not all small satellites are, well, small satellites. A spacecraft that weighs between 100 to 500 kgs is called a mini-satellite. If it weighs between ten to 100 kgs, you would call it a micro satellite. A nano satellite’s mass range is between 1 and 10 kgs. And if your spacecraft weighs between 100 grams and 1 kg, it would be called a pico satellite. That’s not all! We even have a name for satellites that weigh less than 100 grams. They are known as femto satellites.
Research firm, Markets and Markets has predicted a bullish future for the small satellite industry. The nano and microsatellite market is estimated to grow from $702.4 million in 2014 to $1,887.1 million in 2019. A study by Northern Sky Research predicts earth observation as the primary driver behind this growth. This is because earth observation market suffers from data poverty in many industry verticals, like agriculture, disaster management, forestry and wildlife. The research firm believes that a staggering 40 percent of the nano and microsatellites, which are to be launched by the end of year 2024, will be for earth observation applications. It’s safe to say, in the future, small satellites are going to play a big role.
One rationale for miniaturizing satellites is to reduce the cost: heavier satellites require larger rockets with greater thrust that also has greater cost to finance. In contrast, smaller and lighter satellites require smaller and cheaper launch vehicles and can sometimes be launched in multiples. They can also be launched ‘piggyback’, using excess capacity on larger launch vehicles. Miniaturized satellites allow for cheaper designs as well as ease of mass production.
Another major reason for developing small satellites is the opportunity to enable missions that a larger satellite could not accomplish, such as:
- Constellations for low data rate communications
- Using formations to gather data from multiple points
- In-orbit inspection of larger satellites
- University-related research
- Testing or qualifying new hardware before using it on a more expensive spacecraft
The nano satellite and micro satellite segments of the satellite launch industry have been growing rapidly in recent years, and was based on the Spanish low cost manufacturing for Commercial and Communication Satellites from the 1990s. Development activity in the 1–50 kg (2.2–110.2 lb) range has been significantly exceeding that in the 50–100 kg (110–220 lb) range.
In the 1–50 kg range alone, there were fewer than 15 satellites launched annually in 2000 to 2005, 34 in 2006, then fewer than 30 launches annually during 2007 to 2011. This rose to 34 launched in 2012, and 92 launched in 2013. European analyst Euroconsult projects more than 500 smallsats being launched in the years 2015–2019 with a market value estimated at US$7.4 billion. By mid-2015, many more launch options had become available for smallsats, and rides as secondary payloads had become both greater in quantity and with the ability to schedule on shorter notice.
PSLV-C40 carries a Microsatellite (Microsat) built by ISRO as a co-passenger payload. Microsat is a small satellite in the 100 kg class that derives its heritage from IMS-1 bus. This is a technology demonstrator and the fore runner for future satellites of this series. The satellite bus is modular in design and can be fabricated and tested independently of payload.
Space closer to a wider audience
Covert organizations, geopolitical rivalries, astronomical (pardon the pun) budgets, technology nearly indistinguishable from magic: a clichéd view of space exploration, but not an inaccurate one. Starting with the world’s first artificial satellite, Sputnik I, through the intense rivalries of the Cold War, and even down to India’s IRNSS navigation platform, space has mostly been the exclusive domain of nation-states (or powerful corporations).
But all that’s changing now. In what’s a fitting corollary to today’s start-up-focused, agile-is-smart, small-is-beautiful world, satellites have shrunk, physically as well in terms of budget, and are now within the reach of start-ups and educational institutions. From Australia to Silicon Valley, or even here in India, there’s a new boom in space, one riding on the shoulders of low-cost, lightweight satellites.
Traditional satellites can weigh as much as a few tonnes (the GSAT-11, the largest satellite built by the Indian Space Research Organisation, or Isro, tips the scales at just under 6,000kg). At the other end of the spectrum is KalamSat, weighing a miniscule 64g, designed by Space Kidz India, which offers hands-on and technology training programmes for students. Of course, this would be a meaningless comparison without taking into account the difference in their capabilities. The GSAT-11 is a full-fledged communications satellite, while the KalamSat was a technology experiment and test-bed that carried a handful of sensors to collect data for future missions.
In general, satellites that weigh less than 500kg are deserving of the tag “small satellite”. However, it’s the really light ones that have become popular. You will find several weight classes emerging over the years: microsatellites (10-100kg), nanosatellites (1-10kg), picosatellites (100g-1kg), and femtosatellites (under 100g). Awais Ahmed, founder and team lead of the Bengaluru-based Pixxel, which straddles the fields of machine learning and satellite imagery, describes this in layman’s terms, “Anything from a shoebox to a refrigerator.”
Why the emphasis on size? Cost, for one. Traditional satellites, such as India’s GSAT and Cartosat series, are expensive. Cartosat 2E, launched in 2017, had a budget of ₹160 crore, while the cost for the GSAT-9 communications satellite mission eventually touched ₹450 crore. Now compare this with a 1kg CubeSat, which could cost as little as ₹2.5 crore.
“Over 60% of the budget for a satellite mission is the cost of launching it. Lower mass offers a cost advantage,” explains Rifath Sharook, chief technical officer of space education company Space Kidz India and lead scientist for the KalamSat mission. Combine this with the remarkable advances made in electronics over the years, and we are finally at a juncture where lightweight, specialized satellites based on affordable, off-the-shelf hardware can be a viable alternative to their larger cousins.
Yes, there’s a vast gap in capabilities, and you wouldn’t expect a shoebox-size satellite to replace a multi-million-dollar machine, but what if you don’t need all that power? As the saying goes, why use a sledgehammer to crack a nut. Nick Allain, brand head for Spire Global, which bills itself as a “data company that uses satellites as the means of collecting this data”, points out how small satellites are critical to their business model. “There is no way we could have offered the services we do at our price point with a traditional solution,” says Allain.
Cost saving is just one reason for the popularity of small form factors. Equally important is their role in creating what Ahmed calls “responsive access to space”. Significantly less time is needed to build one (anything from a week to a couple of months, versus a few years for a larger satellite), so it’s easy to launch upgraded versions every few months, or even put up a massive constellation for wider coverage within a very short span. This speeded-up development process also allows for a regular launch schedule, making planning for future missions a lot simpler.
Allain points out how Spire builds its satellites in batches of four-eight. “It’s an iterative process. You learn quickly what works.” According to Allain, it’s now possible to build a satellite in a day, and even with testing, the process requires less than a week—something that would have been impossible a few years ago.
The future is bright
But the greatest impetus for small satellites has come from the way they cater to new applications. SpaceX has plans to launch 12,000 satellites as part of its Starlink broadband project. Meanwhile, Spire, which has 60 satellites in orbit, offers maritime and aviation tracking (for uses as diverse as supply chain management, data collection for investors, environmental compliance and emergency response) and even weather forecasting. On the other hand, Pixxel, which will launch three satellites next year (with plans for another 30 by 2020), promises near real-time imagery for crop monitoring and fighting illegal mining. Then there’s Australia’s Fleet Space Technologies, which offers a satellite gateway for internet-of-things sensors (which connects on-ground sensors to a satellite link) for use in remote areas in the mining, agriculture and maritime industry (Fleet is currently using Iridium satellite constellation, but is in the process of launching its own as well).
Many factors have come together at the right time to create what Allain describes as the “space-as-a-service” industry. It’s also interesting how these small satellites have attracted young students. Sharook was part of the student team (he was in high school) that created KalamSat. The founders of Pixxel worked together on BITS Pilani Goa’s Project Apeiro, which used a balloon-launched satellite, while the founders of Spire met at the International Space University in France. Today, it would be hard to pick out a university that’s not working on its own small satellite programme. There’s also official recognition. Isro is offering free training to students from developing nations, while the Indian Technology Congress Association’s India@75: Students’ Satellites programme hopes to enable the launch of 75 student-built satellites by 2022.
While small satellites might be getting a lot of attention, they have some limitations. Usually launched in lower orbits, their lifetime is affected by orbital decay. It’s not much of an issue given the lower cost and the fast pace of development, the bigger issue is that of physical capacity. Battery backup constraints and the available space limit how powerful these small satellites can get. We’re a long way off from expecting small satellites to take over a full-fledged communications role or to provide very high-resolution imagery. But Sharook remains optimistic, given the pace of technological improvements. “Parts will become smaller, power requirements will come down,” says Sharook. The future is bright.