Our dependence on space tech is greater than ever before, and this reliance is only expected to grow as technology advances. Plenty of routine activities we take for granted are backed by satellite technology, which is growing more sophisticated and reliable year after year. But this reliability results from hard work and rigorous testing of all satellite components, which is why spacecraft often take so long to manufacture.
Below, we will discuss the main uses of satellite technology back on Earth and explain why reliability control is so important. Besides, we will list essential spacecraft components that must undergo the most rigorous checks, explaining why a single failure could have major consequences — using real-life examples.
Why are satellites important?
To really answer this question, one must understand — what is the function of the satellite? In its simplest, rawest form, a satellite operating in orbit collects data and sends it back to Earth for analysis. However, the actual data and its applications vary dramatically. Today, we already rely on space tech for:
- Communication, including our access to mobile networks and internet services;
- Navigation, primarily through GPS satellites, which also help businesses with transportation and logistics;
- Emergency response to natural disasters, such as floods, earthquakes, etc., as well as alleviating their consequences through humanitarian aid and rescue efforts;
- Environmental monitoring, tracking climate change, and pollution levels, and searching for ways to minimize harmful impact — for example, through monitoring and preventing illegal mining, fishing, poaching, etc.
Even this list barely scratches the surface because each spacecraft goal described above can ensure a series of additional ‘sub-tasks’ within each mission category.
Reliability control in satellite components
To ensure spacecraft can cope with all of the above tasks, they are equipped with highly advanced electronic components that undergo strict reliability control. By reliability, space engineers typically mean a satellite’s ability to perform its functions in a harsh space environment. However, the actual definition is way more multi-dimensional and may imply spacecraft durability, overall operation logic, and the possibility of fixing any anomalies remotely.
So, spacecraft reliability presupposes testing all satellite components to ensure every little piece of equipment runs smoothly. And, even in case of a minor anomaly, failed components should not interfere with spacecraft operation or integrity.
<img alt=”Satellite with solar arrays”>
What are the components of the satellite?
Now, let’s dig a little deeper and list essential equipment any spacecraft should have to operate in orbit, explain practical uses of satellite components, and discuss some real-life examples when a single component failure caused major service disruptions — component by component!
Power System
This satellite component typically includes solar arrays (if orbit placement has enough sunlight), batteries, or both. The received power is later sent to all other satellite components over a power distribution unit. Clearly, if this component fails, the entire spacecraft will quickly go out of operation. In 1994, several navigation satellites in the Galileo constellation experienced power system failure, resulting in major communication delays.
Communication system
This component receives and sends data to ground stations. Typically, it includes antennas, transponders, and receivers. But what is reliability in satellite communication? In most cases, it implies setting backup communication paths to prevent complete contact loss. So far, there have been no recorded cases of entire communication system failure, even though many satellites experienced disruptions.
Attitude and Orbit Control System (AOCS)
As a satellite component, AOCS ensures spacecraft remains in its correct place. Typically, it relies on thrusters, gyroscopes, and reaction wheels to maintain the correct orbital position or make necessary adjustments to it. Reliability control of this segment involves testing positioning sensors for accuracy and response time. A failure in AOSC can entirely disrupt communication with the spacecraft, as with the Galaxy IV communications satellite in 1998.
Thermal Control System
Thermal components ensure proper temperature regulation within a spacecraft, which is extremely important in space, with temperature fluctuations ranging from -220°C to +220°C. Once again, failures in thermal control can result in entire spacecraft loss—for example, the Mars Climate Orbiter burned up on Mars in 1999, which cost NASA around $125 million.
Data Handling and Processing System
Similarly to communication segment components, data handling ensures communication with the ground station. But it also communicates with all other satellite components onboard. Essentially, this is a computer that stores all information and redirects commands from the ground. In 2012, the GOES-13 weather satellite experienced a data handling failure, and much of the important information was lost. Eventually, the satellite was replaced — but, of course, not without financial loss.
As you can now see, the satellite components list is not too long, but the equipment used in spacecraft is very advanced. That’s why satellites must undergo rigorous testing to prevent failures and, when they occur, ensure the consequences can be dealt with quickly. Judging from the examples of notable failures, engineers are coping with such a challenging task, which means we can keep relying on space tech for many routine activities.
