Losing a satellite is a big deal – its not like losing your car keys. So, once contact with a satellite is lost what actually happens? Dr Lily Qiao from UNSW Canberra explains how satellites might become lost and what happens after we lose contact with them.
The answer is yes, satellites can be lost.
Sometimes, satellites can have problems, like losing contact with their controllers on Earth, getting into technical glitches, or even bumping into other space stuff. If a satellite can't talk to us, or if it stops working correctly, we might consider it "lost."
It then becomes a priority for those working in space surveillance awareness, who keep an eye on satellites, to find the “lost” satellite – which can be like finding a needle in a haystack.
With space being vast and satellites being quite delicate, they can sometimes go missing due to technical issues, collisions, or just wearing out over time.
The frequency with which satellites are "lost" in space can vary, depending on several factors. Generally, space agencies and satellite operators take great care to plan and operate satellites, minimising the risk of loss.
However, occasional losses do occur due to technical malfunctions, communication failures, collisions, or other unforeseen events. It's essential to note that most satellites are carefully monitored, and efforts are made to extend their operational life.
The space industry continually improves technology and procedures to enhance satellites' reliability, but space's vastness and complexity still pose challenges.
When a satellite loses contact, it's a bit like parents losing touch with their child who is on a faraway adventure. The people on the ground responsible for the satellite (the parents) get worried and then try to figure out why they lost contact and how to get it (the child) back!
The satellite might keep doing its tasks on its own, orbiting quietly in space. However, if something goes wrong, it could stop working correctly.
Sometimes, it might start drifting away from its planned path like a balloon floating away. Without someone guiding it, it could become space clutter, or if it's in a lower orbit, it might reenter Earth's atmosphere and burn up like a shooting star. Imagine trying to call your child but not hearing back—satellites in a similar situation might carry on silently in space or face different fates based on their design and where they are in the sky.
Staying in contact with satellites in space is done through unique spots on Earth called ground stations with powerful antennas (e.g. Canberra Deep Space Communication Complex) that send and receive signals via radio waves to and from the satellites.
These antennas must be pointed in the right direction, so it's a bit like aiming a flashlight at a moving object.
The satellites send us updates about how they're doing, which we call telemetry and if we need the satellite to do something specific, we can send it commands.
This way, even though the satellites are up in space, we can keep in touch and make sure they're doing their job correctly.
Yes, it's possible to bring satellites back to Earth safely, but it depends on how they're designed. Some satellites have special engines that allow them to lower their orbit until they reenter Earth's atmosphere gradually.
Once in the atmosphere, they burn up due to the heat caused by friction. It's a bit like guiding a spaceship to return home.
Others may be moved to a higher "graveyard" orbit to reduce the risk of collisions with operational satellites.
Some satellites are designed with capsules that can separate and come back to Earth, like a mini spaceship returning with valuable experiments or samples.
However, not all satellites are brought back—many are left in orbit or moved to specific orbits when their job is done.
The key is careful planning to ensure safe returns and avoid adding to space debris.
Dr Lily Qiao is a Senior Lecturer in Space Systems Engineering at the School of Engineering and Technology (SET), UNSW Canberra campus.
Lily completed her PhD in Guidance Navigation and Control in 2011, including a study exchange at the School of Surveying and Spatial Information system at the University of New South Wales, Sydney.
Her research interests lie in space engineering, systems engineering, and applying Systems Engineering computer-based analysis methods on including, but not limited to, engineering systems.
Dr Qiao specializes in a wide range of topics, including autonomous spacecraft navigation based on Global Navigation Satellites System (GNSS) and celestial navigation, spacecraft attitude determination and control, system modular analysis, data clustering, and network analysis. Click here to read Dr Qiao's profile.
If you would like to speak with Dr Qiao about satellites or spacecraft navigation you can email her at l.qiao@unsw.edu.au