1. Stellant Systems is a new name for a company with a storied history. Trace the genealogy for us.
There are three paths that led to what is now Stellant Systems: Charles Litton’s San Carlos, Calif., Engineering Laboratories, originated in 1932; coupled with Howard Hughes’ Torrance, Calif., Microwave Tube division that started in 1959; along with multiple acquisitions and consolidation of divisions that operated under larger organizations—Sylvania, Loral, GM Hughes, Sperry, GE, RCA, Raytheon, L3Harris, to name a few—led to what is currently the three Stellant Systems locations at Torrance; Williamsport, Pa. and Folsom, Calif.
What is now known as Stellant Systems was purchased by Arlington Capital Partners (ACP), a Washington D.C.-based private equity firm, in October of 2021 because they saw it as an especially unique asset within the defense electronics ecosystem.
2. What markets and products are you focusing on in this new chapter as a private company? Does this reflect any shift in strategy?
I would say Stellant is re-dedicating itself to those market area strategies where we know our products and services make a difference, adapting to those market demands rather than shifting our strategy.
We cover a broad array of markets, cross-sectioning defense, space and commercial. Stellant products are used in defense systems protecting the U.S. and its allies around the globe, as critical power amplification products in radars, air defense missile and counter UAS systems, airborne and sea-based electronic protection systems, etc. But we also offer key products in sight- and life-saving medical devices, synthetic diamond manufacturing, television broadcasting and laboratory and university research.
We see space—in all orbital areas—as a vital industry, where higher frequency and power coupled with size, weight and power consciousness will continue to grow. Stellant is one of only two manufacturers of space-qualified traveling wave tube (TWT) amplifiers (TWTA) in the world, and we are the only one in the U.S.
Electromagnetic spectrum operations (EMSO) is a resurgent market area for the types of products Stellant makes, particularly our helix TWT and microwave power modules (MPM), and we are excited about supporting companies and military services around the world that are helping put the U.S. back in a position of excellence in that domain.
3. What's the breadth of your product portfolio, in terms of frequency coverage and power?
Stellant currently has a deep portfolio of RF amplification products, and we are actively looking to expand that portfolio where it can help us meet specific customer product and/or mission gaps. From our existing product offerings, from klystrons and magnetrons to TWTAs and MPMs, power outputs range from a few watts to megawatts, depending on the product; and frequency coverage ranges from low bands, such as L-Band for Cobra Dane, up through mmWave for electronic warfare and space-based applications.
4. Give us a sense of the size and footprint of the company.
Stellant is an ISO 9001:2015, AS9100:2016, DCMA certified company currently employing more than 800 people at three U.S. manufacturing facilities.
However, as an ACP-owned “platform” company, we are actively looking to grow Stellant’s footprint in our market areas. We are constantly looking for high impact technology companies in the RF spectrum to join with us and ACP, who has a solid reputation as being “founder friendly” and very receptive to investing further capital behind businesses with growth opportunities.
5. You said Stellant is the only supplier of space-qualified TWTs in the U.S. As the space market is in the midst of a resurgence, from new satellite systems to space tourism, how is this tapping your capabilities?
I agree that the market is really bouncing back and opportunities—especially as the demand for higher power and higher frequency continues to grow—are increasing.
But I also believe that in order for the U.S. to regain the technological “high ground,” the domestic industrial base needs immediate attention. As you may be aware, in a recent report entitled “State of the Space Industrial Base 2021,” the Atlantic Council noted that “while the pace of innovation and investment in the U.S. is at an all-time high, participants [in its report, including the Space Force and Defense Innovation Unit] cautioned that this will not be sustained without strategic direction, robust adoption of commercial space capabilities expressed in meaningful contract opportunities, [and] attention to fragile domestic supply chains…”
Those concerns extend to the fragile industrial base that supports the manufacture of space-qualified TWTs and TWTAs. Space-qualified TWTs are extremely specialized due to the rigors of the design, assembly, testing and reliability screening. Therefore, the market has very high barriers to entry, resulting in only two Western-based companies supplying U.S. defense, NASA and many commercial satellites.
We are actively working to improve and reduce the risk to the TWT critical supply chain, as described in the Department of Defense Annual Industrial Capabilities Report (IC Report) to Congress in 2018, 2019 and 2020, where it concluded that investment is needed to spur development of TWTAs better suited to the small satellite market and asserting that having a strong domestic source would reduce dependence on the foreign source and ensure availability of National Security Strategy (NSS) specific TWTAs.
6. Where is the technology border between tubes and solid-state? How do you choose between the two when developing a new product?
TWTAs and solid-state power amplifiers (SSPA), I think, are really two sides of the same coin. Both provide power amplification across a range of frequencies, with SSPAs generally best suited at lower powers and frequencies, while tubes generally excel at higher powers and frequencies—think mmWave in medium Earth orbit and higher orbits or mmWave electronic jammers on ships or aircraft.
Highly efficient, high power amplifiers are required for two primary reasons today: 1) the constant addition of new electronics packages to system RF chains are consuming existing power margins and 2) the increasing stand-off requirements (i.e., distance from threat or target). The future of the electronic attack side of electronic warfare (EW) is through coherent waveforms, i.e., called “digital EW,” instead of noise, but power is still required to send those smart waveforms across long distances.
At the recent AOC Electronic Warfare Gaps and Enabling Technologies Conference, the EW Science and Technology panel discussed this very issue. Solid-state amplifiers are closing the power gap faster than the bandwidth gap when contrasted with vacuum tube electronics. For instance, several solid-state amplifier manufacturers now offer > 250 W amplifiers in X- and Ka-Band, but they cover no more than 200 MHz bandwidth. In addition, there are two different 400 W solid-state X-Band amplifiers in production today. These small bandwidth, high power solid-state amplifiers seem to work for concepts like small swarming, unmanned systems, where discreet units can be programmed to cover segmented portions of the entire threat bandwidth. But tube technology is still required and, in many cases, demanded to deal with very large bandwidth threats.
SSPA’s are getting better than they were in the past in the thermal efficiency area, especially with the temporary (spray on) treatments available for components, but tubes are, as a rule, more efficient across the board.
Finally, size, weight, power, efficiency and form factor matter. SSPA’s are also demonstrating greater “line replaceable unit” functionality—think ease of replacement at the flight line or on board ship—than generally associated with TWTs, but that is something our industry is working to improve. A good example of TWT LRUs are the tubes used in the U.S.’s premier EW jamming pod, the U.S. Navy’s ALQ-99, where Stellant tubes have been in use and replaceable at the unit level for decades.
7. Perhaps superficially, we think of tube technology as mature. Yet you are probably investing R&D to improve the performance of the underlying structure and to expand your product line. Tell us about the frontiers of tube technology.
As I stated above, our industry is investing in the future of TWT technology across many fronts, precisely because of the need for high-power across a wide part of the frequency spectrum and because the need for higher frequency utilization continues to grow.
Stellant, thanks to our “re-birth” as part of the ACP portfolio of companies, is investing in the research and development as well as engineer and technician training and capital equipment to do just that.
We are very proud of our industry-leading K-Band Quad Space nanoMPM®. It’s a state-of-the-art RF power amplifier for use in satellite downlink applications, specifically designed to enable the next generation of software-defined satellites utilizing phased array antennas for increased flexibility on-orbit.
We are also investing in manufacturing process improvements to really meet the increasing customer demand for products in the time frames they need them.
8. Tubes require high voltage (HV) bias—not your standard off-the-shelf power supply. Do you develop your own power supplies?
Stellant is the only vertically integrated space TWTA supplier in the world. We manufacture all in one: TWT, HV power supply, predistorter/preamp (LCAMP). MPMs and TWTAs are TWTs integrated with a power supply.
9. Reliability is one of the cited disadvantages of tubes. What are the primary failure mechanisms? Is it possible to improve reliability?
We have a tremendously experienced engineering team, who help keep me out of trouble for these questions!
The citations referencing TWT reliability, I think, are somewhat dated and stem from a few perceptions: Tube reliability in “the old days”— circa 1950s glass vacuum tubes in computers—were suspect in reliability and that reputation persists, unfortunately. We have obviously developed, matured and improved TWTs in the 70-odd years since that was true. I am sure some users have experienced poorly designed TWTs or TWTAs that had a higher than representative number of failures in the field and, in some cases, people are simply misinformed.
Today’s modern, all-metal-and-ceramic TWTs and well-designed power supplies with correct HV stand-off have proven to be extremely reliable. It’s all about design margin and cost at this point. TWTAs can be as reliable as we decide to build them.
Stellant’s on-orbit FIT rate (failures per billion hours) is exceptionally low, well below what you would predict with analysis. Our TWT FIT rate is less than 50 and the TWTA FIT rate is less than 100 for all Stellant TWTAs. Based on reported failures and approximately 20,000 units and 2 billion total operating hours for all TWTAs in space, of those failures, most are related to the power supply.
Recall that the Voyager spacecraft, launched by NASA in the 1970s and now traveling well beyond our solar system, are still reliably communicating back to Earth through Stellant X-Band TWTs. That’s tellable!
10. What career path led you to Stellant Systems and what keeps you engaged?
That makes me smile. I’ve spent over 30 very good years in the U.S. Air Force and the defense industry, where I learned and internalized key lessons and behaviors that have led to being a member of Stellant Systems’ leadership team.
I first learned and, today, firmly believe that the mission comes first; individual needs are second to that. In business, that mission is our customers.’ Secondly, no one person can do everything; it takes a team, where each member of that team has a distinct skill and role in accomplishing the mission. When we all accept and carry out those roles, it’s amazing what we can do.
Combine those two things, and I can truly say I am at Stellant Systems now because I believe in our “mission,” and I believe in our team. I trust our CEO and all our leaders to excel in their roles, and they expect the same of me. So I guess you could say, I followed the mission and it ain’t done yet!