This article originally appeared in the Aug. 13, 2018 issue of SpaceNews magazine.
Radar images are not pretty. They tend to invite comparisons to grainy black-and-white TV broadcasts from the 1950s. But in the age of artificial intelligence, a treasure trove of data can be extracted from these grainy images. Another plus: unlike electro-optical satellites that need light and clear skies to gather imagery, radar satellites can see through any weather, day or night.
More companies and investors are moving to capitalize on the potential of small satellites equipped with synthetic aperture radar, creating what looks likely to become a highly competitive market. SAR services through low-cost smallsats is a segment of the industry that is being closely watched. Governments around the world also have been paying attention.
One would-be player in this sector is Trident Space Inc. of Fairfax, Virginia. It plans to launch its first SAR smallsat in 2021, followed by six more satellites in 2023, and 12 each year thereafter, eventually building a 48-satellite constellation in low Earth orbit.
President and CEO Nick Karangelen says “affordable services” and timely data is what will help startups like Trident compete in a crowded market.
Trident Space is designing the satellites, including the bus structure, payload and electrical power system. “We are evaluating several potential business partners who will assume responsibility for the remaining bus avionics and spacecraft assembly, integration, and test for our first flight unit,” said Karangelen. The partner will then manufacture approximately 12 spacecraft per year for each of the constellations that are built for various customers. “We expect to make a final decision on our manufacturing partner this year as we prepare to start the first flight unit for launch in 2020.”
As with any remote-sensing service, refresh rate is key. The first of Trident’s SAR satellites will offer two to five revisits per day for most latitudes. The six-satellite constellation will provide an average of 20 revisits per day. The fully populated 48 satellite constellation will bring revisit times to below 10 minutes.
“We strongly believe that the future of Earth imaging is in providing businesses government agencies and [non-governmental organizations] with critical information that can be extracted automatically from the SAR imagery we collect,” he tells SpaceNews.
Trident Space has begun discussions with data analytics companies on possible ways to apply machine learning to SAR imagery, he says. “Our strategy is teaming with selected data-analytics partners for specific markets where information extracted automatically from SAR imagery can provide compelling value.”
Karangelen predicts Trident Space satellites operating in inclined orbits will have higher revisit rates than satellites in sun-synchronous orbits and will be capable of imaging through an eclipse. SAR smallsats will collect images from one-meter to 0.3-meter resolution.
Pricing for one-meter-resolution SAR imagery will be about $10 per square kilometer. Karangelen says that price will ensure the company can compete aggressively in the United States and internationally.
“We expect that a majority of our SAR imagery will be purchased by government and military users in the U.S. and allies,” says Karangelen. “We have no intention of competing directly for Defense Department or intelligence community contracts but are discussing strategic relationships with potential partners to sell into the U.S. government as well as foreign markets.”
— Nick Karangele, Trident Space president and CEO. Credit: Trident Space
Over the next few years, companies like Trident will be closely monitoring advances in SAR technology. The miniaturization of electronics for space is a key issue. “SAR performance is highly dependent on antenna size,” says Karangelen. Improved composite technology and manufacturing techniques have helped slash the cost of large aperture X-band antennas. Trident Space recently completed an internal preliminary design review for its SAR smallsats. It concluded that the best option is a 300-kilogram satellite that is compatible with the growing lineup of commercial dedicated and ride-share launch options.
The design review was developed internally with the assistance of a select group of engineering services companies that specialize in satellite design, said Karangelen. The review was focused on satellite subsystems that are unique to the SAR mission — antenna, bus thermal design, X-band high-power amplifier and spacecraft power electronics. “The results show adequate system design margin consistent with our business and technical goals,” he said. In addition to the space segment, the design review looked at the ground segment, mission planning segment, and data product storage and processing.
At 300 kilograms, these are “not-so-small” satellites with an on-orbit life of four years and a lifetime SAR image collection capacity of 44 million square kilometers at 1 meter resolution, Karangelen says. At $10 per square kilometer, that’s a lifetime earning capacity of $440 million for a satellite with an on-orbit cost of about $42 million.
An engineering model of the company’s SAR payload electronics has been tested on a Cessna aircraft. The payload technology was developed by Trident Systems Inc. The company flew the engineering model of the payload electronics on a small aircraft and collected raw SAR data around Southern Maryland. Karangelen said the results of these tests “confirm sub-meter resolution performance of the payload electronics.”
Turning data into insightful information will be the secret sauce, however.
“We believe advanced data analytics in the form of machine learning is a key to our future success,” he says. “No one in business really wants to look at pictures. They want a reliable, consistent source of affordable information required to support their most critical business decisions.”
The use of machine learning to extract information from electro-optical imagery is a booming industry. “However, the applications of machine learning to SAR has been delayed by the lack of large, affordable SAR image data sets required for neural network training,” says Karangelen.
In response, Trident Space plans to conduct periodic high-resolution airborne SAR data gathering starting in early 2019. The plan is to collect SAR imagery at the same grazing angles, resolution and quality that would be collected from space. “We will use these SAR images, and concurrently collected electro-optical images at the same resolution, to create a portfolio of annotated SAR image data sets to support training of machine learning algorithms,” he says. “Using this approach, we hope to establish a foundation for automated SAR data analytics development.”
Trident Space wants to team up with emerging data-analytics companies while it tests the market for business information applications of SAR prior to the launch of the first satellite.
Karangelen predicts smallsats will become increasingly more capable as remote-sensing platforms. “Certainly, there are limits to what can be accomplished on a SAR smallsat,” he says. Some important technical achievements of late are increased power and storage capacity for small satellites. “RF power, payload processing power, and available antenna aperture size will continue to improve in incremental steps.”
Low-cost launch will be essential to the survival of this industry, says Karangelen, who is also an investor in Tucson, Arizona-based small-lift startup Vector. “In my view, affordable launch will set the pace in this new generation space race. Companies like Vector will be fully subscribed as they offer small satellites affordable access first to LEO and then beyond,” he says. “I believe our biggest schedule risk in the future will be launch availability.”
Trident Space is privately funded and expects to close on a $7 million Series A round of financing in September.
