Swedish satellite trackers will reduce the risk of space crashes

The number of objects in orbit around the earth is increasing at a dramatic rate. The basis for this is, among other things, satellite-based research and companies that send up large fleets of satellites to provide worldwide internet.

The increasing number of satellites increases the risk of more collisions, which in turn can lead to more space debris in orbit. In 2007, China tested an anti-satellite missile on one of its weather satellites, a collision that increased space debris in orbit around the Earth by 25 percent. The first collision between two satellites took place in 2009 between the American Iridium-33 and the Russian Kosmos2251.

Recently, the state-owned company implemented Swedish Space Corporation (SSC) sine first tests of a satellite tracking optical station with the purpose of cataloging objects in space as part of handling the increasing number of satellites in our immediate space.

An accurate spatial image is important

Jacob Ask is the program manager for Space Situational Awareness (SSA) on SSC. SSA is called the space situation image in Swedish and is about getting a picture of the position in space to avoid satellite collisions, among other things.

– SSA has been a very important area for a long time, but became even more relevant in 2007 and 2009 when two serious collisions occurred in our immediate area. The collisions resulted in an incredible number of smaller fragments of satellites orbiting the earth, which still affects the space environment today, says Jacob Ask, who also leads the project with the satellite tracker.

With the increasing number of satellites around the earth, it is becoming increasingly important to have reliable cataloging of the objects’ orbits for safer space traffic.

– In short, it can be said that SSA is incredibly important to avoid collisions between active and inactive objects in space, says Jacob Ask.

There are different ways to collect SSA data. One way is to use large radar instruments. A more cost-effective approach may be to use optical telescopes, and that is the path SSC has taken in this project.

– There are significantly lower costs. Then there are different types of data you can get out. Both in terms of volume, ie how many objects you can detect during a certain period of time, and at what height you can easily detect objects at. With an optical instrument, for example, we have no problems at all looking in a geostationary orbit, which is much more difficult with a radar, says Jacob Ask.

The tests exceeded expectations

The optical station has been built from components provided by the companies Planewave, Andor and Baader Planetarium, among others. The latter has also been responsible for the installation of the station, which will track satellites through the sunlight they reflect.

– There are very few satellites that have active lighting, but they do reflect sunlight. First, reflected sunlight from an object is detected and then we can use image processing and algorithms to compare the object’s position in relation to the stars under several images to make a trajectory determination, says Jacob Ask.

The station is made up of many components, including two telescopes and two cameras. But it is above all the cameras that raise the quality of the observations.

– It’s an incredibly good telescope, but it’s the choice of cameras that’s the big thing. We have two sCMOS cameras (scientific complementary metal – oxide – semiconductor) that not many people use to generate SSA data. The most common is that SSA stations have CCD cameras (charge-coupled device). So we have faster cameras with low noise. This allows us to make many more observations and take many more pictures. We can then maximize every second that we make observations and maximize our data to build the best and most efficient station in the world, says Jacob Ask.

The first tests were conducted in March this year at the Baader Planetarium in Germany. After being in place for three days and assembling the instruments, the first satellite was captured on image. In this case, the telescope followed the satellite’s orbit, which is therefore visible as a dot in the image. The surrounding stars appear as dashes because the shutter speed is longer than zero.

– We were well prepared for the tests, but assumed that what can go wrong will go wrong and that it is not certain that we will be able to make an observation on the spot. But already after three days we were able to make an observation, it was really above expectations and I am proud that the team managed to get everything done so early, says Jacob Ask at SSC who leads the project.

The optical station is located in Western Australia

Now that the first tests have been completed, SSC will soon start delivering SSA data.

– When the station is installed, probably at the end of the summer, we will start making observations in the geostationary belt. But soon after that we will start making observations of lower flying satellites in LEO – low earth orbit. We are not going to focus on any specific satellites or objects. We work to detect as many objects as possible. Both satellites and space junk, says Jacob Ask.

The goal is to contribute to a more sustainable use of space, for example by contributing to the detection and orbital updating of space objects for cataloging purposes. And SSC wants to make the system autonomous to increase efficiency.

– What we want to do is minimize whitespace as much as possible – that is, when we can observe, we should observe. And we should be able to do that autonomously in the long run. We will not need to have operators who control the station in real time, says Jacob Ask.

The station will be located at SSC’s antenna facility in Western Australia. There are several benefits to locating the station there.

– Among other things, we have none horizon mask – that is, no large buildings or other objects that interfere with visibility. In addition, Western Australia is one of the absolute darkest places on earth, which makes the night sky absolutely unique. This enables the detection of low-lit objects, says Jacob Ask.

The goal is high-quality data

If everything goes as it should, more stations can be built in the future according to Jacob Ask. He says that a possible upscaling of the project is not a problem, but emphasizes that what SSC is focusing on at present is to produce as high-quality SSA data as possible.

There are several players that currently deliver SSA data. Among other things, there is Europe’s consortium European union space surveillance and tracking (EU SST) which has several stations around Europe. According to Jacob Ask, several of their stations are originally astronomy observatories that have been rebuilt for satellite tracking.

SSC will collaborate with and share its data with several actors. Among other things, they will enter into a data sharing agreement with the German Center for Aerospace DLR and collaborate with local operations in Australia such as Western Sydney University and Silentium Defense.