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1090 Global

From Apollo to Aireon: Our Satellite Expert’s Incredible Five Decade Career


I graduated from Purdue University two years before Apollo 11 landed on the Moon.  My first job was in St. Louis with McDonnell Douglas, which is now Boeing. My supervisor had me look into Venus swingby missions to Mars.  Eight months later, the company needed help in Houston on the Apollo program and I was now their interplanetary expert.  This job was the very beginning of my space career, which has now spanned more than five decades.

One of my past jobs was with Motorola in Phoenix.  In 1989, the system Engineering Team I was part of was looking for new ways to communicate from anywhere to anywhere on the planet.  Many concepts were envisioned and what finally emerged became the Iridium project.  I was one of the first five people assigned to create the Iridium System concept.  During the early years on Iridium, I wrote a Windows program that was able to show how the dynamics of the Iridium System worked.  It proved useful to show the early banker/investors how the system would work and was instrumental in convincing them to invest in the original system.

Dennis in 1963

Dennis in 2015

Years later, in 2009, I rejoined Iridium as the Director of Hosted Payloads.  My role was to find customers to sign up for the 81 hosted payload slots being designed into the next generation of Iridium® satellites.  From 2009 until the end of 2011, I supported private companies and all types of government entities in understanding how their mission needs could be satisfied by a box measuring 40 cm X 70 cm X 30 cm that would fit on the Iridium satellite.  After over 30 studies, the Iridium Team came across a need within the aviation community to receive Automatic Dependent Surveillance-Broadcast (ADS-B) messages from aircraft flying in oceanic airspace.  All aviation infrastructure was terrestrial-based, and could not track aircraft beyond 200 miles from the shore.

The idea of an aircraft transponder receiver as a hosted payload gained traction in 2011 within Iridium, which then led to a Request For Information (RFI). The RFI was sent to a few contractors for feedback.  Then, meetings were scheduled to begin working hosted payload concepts.  I was asked to join the small, new business team as the only engineer on the project.  In parallel with this activity, the mechanical and electrical interfaces for a generic hosted payload were being finalized with Thales, the company selected by Iridium to build the next generation of satellites.  As the year moved on and the idea of an aircraft transponder receiver looked more and more promising, I shaped the mechanical and electrical interfaces between the satellite and the hosted payload to be highly reliable and supportive of a radio receiver type payload.

The project became real when the Request for Proposal (RFP) was issued to six contractors in February 2012 to bid on developing the ADS-B Hosted Payload.  As each contractor’s design concept evolved during the Q&A process, the Harris design emerged as being the most capable, leading to their eventual selection in June of 2012.  This was the first contract awarded by the new company, Aireon, to produce 81 hosted payloads.  Around the time of this contract award, I was asked by Aireon’s CEO, Don Thoma, to become the System Development Program Manager and get the AireonSM system built.  Around the same time, NAV CANADA agreed to join as a major investor.

My immediate priority was to get the first four Harris payload units and the qualification unit delivered on a very tight schedule for “space hardware” programs.  The quality unit needed to be delivered in under 24 months and then shipped to Thales in France to be tested with the first satellite!  The Harris Program Manager developed a one-page summary schedule that showed the design, production and testing activities that needed to be accomplished before Harris could deliver the qual unit and the first four flight payloads.  The one-page schedule never needed an update. Harris delivered the qual unit and the first four payloads on time. Incredibly, the 81 payloads were delivered ahead of schedule; a monumental feat for space hardware development! As on-orbit testing began after the first launch, the ADS-B payloads turned out to over-perform when compared to the original design requirements.  Besides designing a highly flexible and programmable payload, the capability of the payload to receive ADS-B messages from an aircraft was discovered to be 1.82 times greater (in terms of coverage area) than called for in the payload design requirements.  During the constellation deployment timeframe, that old simulation program I wrote in the early 1990s turned out to be useful to generate the coverage times for a partial constellation flying over some of our early customer’s service volumes.  I was able to add the capability to that 20+ year old Windows program to compute when our customers would receive no coverage, partial coverage or full coverage over their service volumes.  The customers have used this data to compare early test data with their current terrestrial based coverage.

Now that the final launch has been completed and all of the operational Aireon Hosted Payloads are in position and configured, my job to “get the system developed” is nearly over.  This year I will continue to support the Aireon team in achieving the objective of getting the Aireon system certified for use by our customers.  Once that milestone has been accomplished, the world’s first space-based ADS-B system will be operational and generating revenue.  It’s been an incredible journey and an amazing project to conclude my five-decade career. I’ve not only assisted Aireon in creating this groundbreaking technology, but I was able to use all of my experience in doing so. With this success, my role at Aireon and Iridium will be complete, and my next step will be riding off into the Arizona sunset to start my next chapter in life — a well-earned retirement.

 Click play to hear more in detail about Dennis’ experiences working on the world’s very first air traffic surveillance system from the expert himself.