“Relatively small yet complex spacecraft can be built and successfully operated in orbit on a budget that is at least an order of magnitude smaller than that associated with a traditional approach,” wrote a British university engineer in the conclusion of a paper about a small satellite program.
That is, in 2016, hardly a surprising statement: recent years have demonstrated that smallsats can increasingly perform missions that used to require larger spacecraft with larger price tags. However, in 1987, the year that paper was published, that was a fairly radical conclusion.
The author, though, knew what he was writing about: Dr. Martin Sweeting led the development of two smallsats at the University of Surrey, and established a company to commercialize that work: Surrey Satellite Technology Ltd. (SSTL), which is today one of the world’s leaders in smallsats. And he was presenting to a sympathetic audience, in the form of the first Conference on Small Satellites at Utah State University.
Today, the conference is one of the world’s leading events in the smallsat field, attracting more than 1,800 people last year to the Utah State campus in Logan for several days of presentations. A similar number of people is expected for this year’s 30th annual conference, taking place August 6–11.
The proceedings of the past 29 conferences are all available online, and offer a review of the evolution of the smallsat field over the last three decades. Many of those papers are quite technical, going into details about the development of spacecraft and their components. Combined, though, they show how the field has grown as smallsats have become more capable, even if they are still dealing with some of the same problems in 2016 as they were in 1987.
The Rise, Fall and Rise of Constellations
Small satellites, of course, were not new in 1987, but were largely relegated to technology demonstration and other, simple applications. “The small satellite concept was ludicrous to many people. Smallsats were thought of as toys, with no relevant value,” recalled Kristen Redd Wilkinson in a 2006 paper marking the conference’s 20th anniversary. “Everyone thought that they required too much ground support for communications and couldn’t perform useful missions.”
That began to change in the early 1990s as a number of ventures proposed constellations of small satellites to provide global communications services. Companies such as Globalstar, Iridium and Orbcomm started to become subjects of conference presentations as these constellations went from concepts to flight.
One of the most ambitious satellite constellations was one called The Calling Network, presented at the 1993 conference. It proposed a network of 840 Ka-band satellites, plus 84 spares, to provide telephone service to developing nations and other remote regions. “Global demand for such service is great enough to support at least three networks of the size described herein,” the paper concludes, “sufficient to propel certain industries to market leadership positions in the early 21st Century.”
If that proposed constellation sounds familiar, it’s because the company developing it, Calling Communications Corp., became Teledesic. Of course, Teledesic never deployed that constellation, or scaled-down versions of it that the company later proposed, and many of the other proposed constellations similarly vanished.
Those smallsat constellations that did launch faced problems more related to business than technology, as Globalstar, Iridium and Orbcomm all went through bankruptcy protection and reorganization. Would it be any easier to do a constellation in the 2000s, given the lessons learned from the 1990s?
Not necessarily, a 2007 SSTL paper concluded, comparing the original Orbcomm constellation with proposals for a next-generation replacement. Smallsats have access to improved technology, but those were balanced by increased requirements and regulatory issues, including export control and orbital debris mitigation. “New requirements and constraints offset small satellite technology advances,” that analysis concluded.
That hasn’t stopped Orbcomm, or Globalstar or Iridium, from developing replacement constellations. Now others are joining the fray, including OneWeb’s 650-satellite system and SpaceX’s proposals for a constellation of thousands of smallsats to provide communications services.
Earth Imaging Comes into Focus
Preceding those new communications constellations have been fleets of remote sensing satellites, packaging into smallsat form factors capabilities that once required much larger satellites. The best known is Planet, formerly Planet Labs, which has placed nearly 150 satellites into space to date, with the goal of a constellation that can provide medium-resolution imagery on a daily basis.
That approach would not be possible without using smallsats. “A system of this scale would be extravagantly expensive if comprised of traditional satellite elements, yet we have attempted this with venture capital funding at a level that would be considered irrationally small by most aerospace standards,” the company concluded in a paper at the 2014 conference.
While smallsats have been providing Earth imagery at lower resolutions for years, the move by some companies into high-resolution images wasn’t foreseen by some conference attendees. A 2001 paper by University of Michigan researchers concluded that smallsats would require advanced technologies, like deployable optics, in order to take such images. “Until such systems become operational, microsatellites are most likely not a cost effective solution for high-resolution images of the Earth,” the paper concluded.
In June, Terra Bella, the Google-owned remote sensing company previously known as Skybox Imaging, launched its SkySat-3 spacecraft, capable of taking images with a resolution of about 0.9 meter per pixel. The spacecraft’s mass: just 120 kilograms.
Here Come the Cubesats
One of the biggest trends in smallsats has been a revolution at the lower end of the market. For much of the conference’s history, satellites weighing several hundred kilograms were considered small — and understandably so, given the comparison to those weighing thousands of kilograms. Today, though, such a “small” satellite seems positively huge compared to the cubesats that dominate the industry, and also the conference.
When cubesats emerged around the turn of the century, their potential looked promising despite their mass and weight constraints. “The notion of building a fully-functional, one-kilogram, one-liter satellite is a very challenging one,” wrote a group of Montana State University engineers in a 2002 paper, one of the first published at the conference about cubesats.
They were optimistic about the use of cubesats for basic science missions, “provided they are small and require little power,” and for technology demonstrations. “Of course,” they added, “innovation and imagination will continue to place more and more interesting payloads into CubeSats.”
That prediction has proved to be accurate. Cubesats dominate the conference today, from a two-day workshop the weekend before the conference to many of the main conference sessions. Their uses have grown, too: Planet’s constellation of remote sensing satellite are three-unit cubesats, a common form factor for a wide variety of missions. And, at the 2015 conference, NASA discussed plans to send cubesats to Mars accompanying the Insight lander (a mission now delayed from 2016 to 2018 because of issues with the lander, not the cubesats.)
The Perennial Problem of Launch
While smallsats have changed in both size and application, one thing has remained constant throughout the conference’s 30 years: the difficulty in getting those satellites launched. It’s a problem that’s had no shortage of proposed solutions, yet nothing that had radically improved access to space.
Over the years, presentations suggested the use of secondary payloads, as well as inexpensive launches on former Soviet ballistic missiles turned into launch vehicles. Those have found some success, but not enough to ease the concerns of smallsat developers. And they had problems of their own: the Montana State group developing a cubesat in 2002 eventually flew it as a secondary payload on a Dnepr launch in 2006 — one that failed.
In the late 1990s, companies developing reusable launch vehicles (RLV) attempted to attract smallsat developers. A 2000 paper by Kistler Aerospace proposed a “Ticket-to-Orbit” concept where smallsat developers would buy slots on regularly scheduled launches of the company’s K-1 RLV. “Kistler hopes satellite designers will find these opportunities so valuable that they will build their buses especially to fit the Kistler interface and envelope,” the company stated. Alas, the K-1 never flew.
In the mid-2000s, the smallsat community pinned its hopes largely on a single company: SpaceX. Its Falcon 1 rocket promised “more affordable, reliable and pleasant” access to space, in the words of a 2003 conference paper co-authored by company founder Elon Musk (“pleasant” referred to the limited vibrations payloads would be subject to during the launch). Falcon 1 eventually flew, but SpaceX retired it after a 2009 launch to focus on the much larger Falcon 9.
The surge of interest in cubesats and other smallsats has attracted a new wave of proposed launch vehicles to serve them. A paper by Orbital ATK at the 2015 conference identified 22 vehicles in service or under development. By the time they presented the paper, they found several more vehicles designed to serve the smallsat market in early stages of development.
Not all of those vehicles will enter service (and some have already fallen by the wayside, like the DARPA-funded ALASA air-launch system), but those efforts are providing new optimism for a smallsat industry finding new ways to use smallsats. The 2015 conference, for example, included presentations on cubesat and other smallsat missions to the moon, Mars, asteroids and even to search for planets orbiting the nearby star Alpha Centauri.
“It’s very difficult not to be bullish about the continued development of microspace in a world where the desire to explore and exploit space is seemingly endless, despite the launch question,” wrote Matt Bille of Booz Allen Hamilton in a 2011 paper that looked at the long-term prospects for smallsats. Given the progress smallsats have made in the last 30 years, it’s easy to see why.