Technology

How to control a satellite flying 27,000 km/h?

How do you communicate with a small cube flying around our planet at a speed of 27,000 km/h? By building a ground station, with antennas on the rooftop of your office building.

Building a satellite and launching it into space are just a part of what we are doing in the Reaktor Space Program. Without a support system on earth, launching a satellite would be like letting go of a balloon: the moment you release the balloon is the last moment you have control over it.

That is why we need a Mission Control Center (MCC) for our Hello World cubesat. The center is built around our first ground station at the Reaktor headquarters in Helsinki. The ground station, utilized by MCC, has outdoor antennas (on our rooftop) and the computers with software are indoors (in our office). There will be more ground stations later, and all of them will be monitored from the Mission Control Center in Helsinki.

From the MCC and ground station, we can send commands to and receive data from the satellite. If you need a picture from space, simply send a command to the satellite from MCC via ground station antennas. Hello World will snap the pictures and send them back to earth.

This is what our Mission Control Center in Helsinki looks like right now. As you can see, our MCC is mostly computers running software, linked via cables to the rooftop antennas in the future.
This is what our Mission Control Center in Helsinki looks like right now. As you can see, our MCC is mostly computers running software, linked via cables to the rooftop antennas in the future.

Helsinki is more or less at the same latitude as Anchorage in Alaska. Or Tobolsk, the former capital of Siberia, Russia. It is far up in the northern hemisphere – which gives us a longer communication time with a satellite in polar orbit.

Reaktor Hello World Ground Station communication window of 10 minutes.

Hello World flies around the globe at a speed of 27,000 km/h, 16 times a day, going from the north pole to the south pole and back in 90 minutes. However, because the planet is rotating underneath it, the satellite flies over Helsinki only three times a day.

It is visible to our ground station around 10 minutes at a time, giving approximately 30 minutes of communication time per 24 hours. Our plan is to have ground stations near our offices in New York and Tokyo as well, thus significantly extending the communication window per day. All the data are sent to our Mission Control Center in Helsinki through the internet.

 

Satellite Ground stations for Polar, Solar Synchronous orbits

We plan to build an array of antennas, including a satellite dish for higher frequencies – a couple of meters in diameter – on top of our office building in Helsinki. Right now we are testing the setup with a smaller, handheld antenna.

All the hardware needed to run a satellite is fun, but Reaktor excels at software, which makes the satellite come alive. Our first goal is to build a fully functional minimum viable product (MVP): an end-to-end prototype that works from our Mission Control Center to the processors inside the Hello World satellite, plus all the necessary technology in-between. Improvements and additional functionality will be added later on top of this.

 

Here is what our first iteration of ground station is capable of: receiving images from the NOAA-19 weather satellite! Looks like we have a part of our MVP working!

More information about Reaktor Space here.