Space Weather Strikes Again

Author: Justin McKennon – justin@ema3d.com

In April of this year (2019), the Boeing-built Intelsat 29e communications satellite (launched in 2016) suddenly failed. A recent investigation concluded that an electrostatic discharge, or a micro-meteoroid strike, was the cause of the premature end of the satellite’s mission. This failure was expensive – costing Intelsat ~$382 million.

This satellite had a planned 15 year mission, provided C-band and data distribution services over South America, and beamed Ku-band signals across the Americas (providing passengers aboard aircraft with TV and internet). Ground based telescopes, operated by ExoAnalytic Solutions, a commercial company that tracks objects in space with a network of optical telescopes, show the Intelsat 29e leaking propellant and debris. On April 10th, Intelsat said that the spacecraft “experienced damage” on April 7th.  ExoAnalytics sensors detected a change in the brightness of the 29e around the time of the event, which suggested that the spacecraft was tumbling. Intelsat said that the 29e experienced a second anomaly on April 9 that caused a loss of communications with the satellite. Debris was detected coming off the satellite over the following few days. The video below, captured by ExoAnalytics, depicts the failure occurring.

(Video courtesy of Space Flight Now)

A micro-meteoroid is a fragment of a meteoroid, typically smaller than a grain of sand. At the immense speeds the satellites are traveling at, it’s easy to imagine the damage that something that small can cause. In case you’re having trouble visualizing that, here’s something for reference :

(photo courtesy of ESA/NASA)

While that may seem fairly obvious, the other potential cause of the failure, was an electrostatic discharge. This is a phenomena that we at EMA are intimately familiar with. The space environment presents some very unique and difficult challenges for spacecraft. On Earth, we’re largely protected by the Earth’s magnetic field and atmosphere from these effects, but in space it’s a whole new ballgame. Contrary to popular belief, space is not empty. In fact, it’s a soup of highly energetic particles – protons, photons, electrons (etc.). Spacecraft and satellites comprise many different materials, and each is impacted by these particles very differently. Design and operating constraints – weight, resistance of materials, and more, further complicate things.

As spacecraft travel through the space plasmas in their respective orbits, they come in contact with electrons and ions, and also receive photons from the sun. In addition to this, spacecraft are also subject to Coronal Mass Ejections (CMEs) from the sun, which sends showers of these particles towards spacecraft as well.

These particles all serve to deposit charge into the materials they come in contact with. Depending on the properties of the material (dielectrics, conductors, etc.) there are areas where charge can accumulate, producing a voltage difference between various areas. If too much charge accumulates, and this voltage becomes too large, arcing can occur.

(Damage to a solar array, caused by arcing, photo courtesy of ESA)

With the massive costs of space programs, it seems logical to try and address these issues in the design phase. EMA has been involved in many of the industry’s largest space programs, and has helped countless customers make their designs safer and more reliable. At the moment, EMA is in the process of developing a test facility to empirically evaluate the effects of spacecraft charging on materials, and in parallel, EMA is also developing a simulation tool to better allow for the analysis of these effects. EMA hopes that these capabilities can help to prevent things like the 29e from occurring!

References:

https://spaceflightnow.com/2019/07/30/investigators-conclude-external-forces-killed-an-intelsat-satellite-in-april/
https://spaceflightnow.com/2019/04/15/stricken-with-fuel-leak-intelsat-29e-seen-drifting-in-geostationary-orbit/