Nerve-wracking four hours: Struggling with the connection to the new Danish satellite

11. januar kl. 09:59
Nerve-wracking four hours: Struggling with the connection to the new Danish satellite
Illustration: Sternula.
Sternula’s launch of its first satellite, sent into orbit on a SpaceX Falcon 9 rocket, was not without drama.
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Shortly before 8 p.m. on the 3. of january, Danish company Sternula based in North Jutland could breathe a sigh of relief and call itself Denmark’s first commercial satellite operator.

Four hours earlier, at 3:56 p.m., a SpaceX Falcon 9 rocket lifted off from Cape Canaveral, Florida, carrying Sternula-1, a tiny 10x20x30 cm nanosatellite.

The satellite is the first of a total of 60 satellites which will deliver the next generation AIS (automatic identification system, ed.)—a maritime surveillance system for ships.

The first task of Sternula-1 will be to broadcast periodic weather and ice alerts in the Arctic and on Greenland for the Danish Meteorological Institute (DMI).

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The entire launch was streamed live on YouTube by SpaceX, and you can just make out the Sternula-1 satellite as it exits the second stage. It happens approx. an hour after the Falcon 9 launch.

Remote video URL

“It was a big moment. This is the last time we see the satellite, and I have to admit that I was more nervous than I had expected,” says Lars Moltsen, CEO and co-founder of Sternula.

Nerve-wracking moments

The first two times Sternula’s engineers tried to establish radio communications, nothing happened, partly because the satellite operator did not have the satellite’s exact position and there was noise from other satellites.

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But shortly before 8 p.m. evening, the third attempt was finally successful.

The technical team from Sternula, Aalborg University, Gatehouse, Satlab, and Space Inventor prepares for the first radio contact. Illustration: Sternula.

“Fortunately, it was not a fault on the satellite that delayed the radio communications. It was quite a relief when we established radio contact,” Lars Moltsen says.

So far, everything looks good.

“We monitor all components for temperature, and it looks reasonable. The satellite spends approx. 45 minutes in the sunlight and 45 minutes in the shadow, and it cools down rapidly while it’s in the shadow. The satellite’s construction distributes the heat from the sun, and it seems to be working,” Lars Moltsen says.

Facts: Sternula-1

Type: 6U CubeSat.
Weight: 11 kg when packed up.
Dimensions: 10x20x30 cm.
Solar arrays: Two fold-out arrays.
VHF antenna: A single fold-out antenna. Transmits over the 160 MHz frequency band.
Transmission speed: Approx. 100 kbit/s.

When a satellite is launched from the Falcon 9 rocket, it is not unusual for the satellite’s trajectory to be imprecise.

This complicates radio communications with Earth because it is difficult to calculate the satellite’s exact trajectory. However, Sternula-1 appears to have a fairly precise orbit determination.

“We have also investigated how the satellite spins around itself. In an unlucky scenario, the satellite could rotate on an axis which prevents the solar arrays from charging properly. It was one of the first things we checked. If the axis turns out to be unlucky, we have flywheels on the satellite that we can turn. But it doesn’t seem like that will be necessary,” Lars Moltsen says.

Ready for operation in April

Now begins a long series of tests of the satellite’s internal components before the primary payload, a VHF antenna, is to be tested.

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“We will start by testing the antenna’s communication with us in the office, and it will soon after communicate with a Royal Arctic Line ship. Then we begin to approach the first real tasks, which will be sending out ice alerts,” Lars Moltsen says.

CEO and co-founder of Sternula Lars Moltsen with a duplicate of the satellite launched by SpaceX on Tuesday. Illustration: Sternula.

The plan is for Sternula to be able to broadcast the first ice and weather reports via AIS from the Arctic in March.

“We hope to be able to provide the service to the first customers by April, and then we’ll start planning the launch of the next satellite, which will hopefully be in two years,” Lars Moltsen says.

Sternula is not the only company working on commissioning dedicated AIS 2.0 satellites. But it is leading the race with the launch of its first commercial satellite.

The 60 Sternula satellites are to be launched into Earth orbit over the next six years.

“We are the first to commercially provide an AIS 2.0 connection to service providers and maritime authorities,” Lars Moltsen says.

Growing North Jutland cluster

Both Lars Moltsen and the other co-founder Stefan Pielmeier come from the antenna and telecommunications industry.

They have not had to go far from Aalborg to get help.

“We are not space geeks, and we are therefore completely dependent on the gradually growing North Jutland space cluster. We even have two satellite factories to choose from just here in Aalborg,” Lars Moltsen says.

In fact, the satellites could hardly be more Jutlandish.

The physical nanosatellite was built by Space Inventor in Aalborg’s Vestbyen, while the radio module was built by Satlab in Aalborg East. Software for backhaul has been developed at GateHouse just north of Limfjorden in Nørresundby.

The run up to the launch on Tuesday has not been entirely without obstacles.

"We had actually booked a launch with Russian Roscosmos. But then came the war in Ukraine, and that meant that we neither could, wanted, nor were allowed to launch satellites from Russia. So we had a quick transfer to SpaceX’s Falcon 9 from Cape Canaveral in Florida,” Lars Moltsen says.

It is somewhat reminiscent of booking a seat on an overseas flight.

“We got a contract with the title ‘ticket to space’. It’s still expensive, but the price has fallen by a third within just three years because there is now real competition in the commercial space payload market, with launches from Europe, the USA, China, India, Japan, and Russia.”

Sternula-1 was supposed to be launched during the World Cup final in football on 18 December. But SpaceX had to postpone the launch of the Transporter 6 mission first to January 2nd and then to January 3rd.

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