Space News and Facts Newsletter #54
May 22, 2022 - May 28, 2022
What is the Space Data Association (SDA)?
Back in 2009, a few of the large satellite companies recognized the need for better, integrated satellite tracking capabilities. As more players came into the industry, the likelihood of collisions was becoming a reality.
In fact, it was in 2009 that the first severe and accidental in-orbit collision happened between an American comm satellite, Iridium-33, and a Russian military satellite, Kosmos2251.
So the SDA was formed by three of the biggest satellite operators of the day: Inmarsat, Intelsat and SES. Together with a fourth large operator, Eutelsat, they today form the Executive Board of the SDA.
Before its formation, collision avoidance was managed by - incredibly - phone calls! This usually meant anticipatory predictions far in advance. Not only that, satellite operators used different data formats and units of measurement, compounding the complexity of the problem.
The only thing going in favour of the industry at the time was the relatively small number of satellites in orbit. That, of course, is not the situation today. About 4,852 satellites are orbiting Earth as of January 1, 2022, according to the Union of Concerned Scientists. (See link below. Includes breakdown of satellites by country and orbital position. FYI: These figures do not include the tens of thousands of pieces of space debris orbiting Earth.)
The SDA says, "The Space Data Association (SDA) is an international organization that brings together satellite operators to support the controlled, reliable and efficient sharing of data critical to the safety and integrity of the space environment. The SDA membership includes the world’s major satellite communications companies."
Most satellite operators today are members of the SDA. This includes some recognizable names such as NASA, NOAA, Hawkeye 360, Planet, Viasat, Iridium, Telesat, and many others.
To facilitate its activities, the SDA needed to be incorporated. They did so by incorporating in the Isle of Man. The Isle of Man, located in the Irish Sea between Great Britain and Ireland, is a self-governing island owned by the British Crown (not strictly speaking a part of the United Kingdom). The Isle of Man is frequently used as a location for the incorporation of international ventures. It is well-known as a tax haven.
The SDA also needed an operational location, the "Space Data Center", which is operated and managed by Philadelphia, USA-based Analytical Graphics, Inc. (AGI). That's interesting.
AGI is either owned by or has become (I can't tell*) "Ansys Government Initiatives" which, in turn, is owned by one of the largest software engineering companies in the world, publicly-traded Anysys, Inc. (NYSE: ANSS).
*AGI's LinkedIn profile says, "AGI is now Ansys Government Initiatives — an Ansys entity dedicated to United States national security customers."
The connection to a top-level US security firm shouldn't be a concern or even surprising. Satellite operators are closely connected to the countries they service and international cooperation is necessary. No borders in space.
SDA members provide "ephemerides" and "special perturbation" data to AGI/SDC's computers. (Ephemerides are just trajectory data.) Members now have immediate access to satellite information.
This is the SDA's website:
Here is Ansys Government Initiatives' website:
Here is NASA/JPL's info on "Orbits & Ephemerides"
Union of Concerned Scientists Satellite Database
In the last week, I've seen a number of articles about the Golden Records on the Voyager 1 and Voyager 2 spacecraft. These disks contain information about Earth designed to be read by life outside our solar system. Some of the information was designed by Carl Sagan.
But equally fascinating is recent calculated projections about just how long these two spacecraft will exist. Both of these spacecraft are now beyond our Sun's Heliosphere, well into interstellar space. They were originally planned to last about 5 years - that was the expectation.
Let me provide some background ...