FEATURE

50 years since the first European satellite

May/16/2018
On 17 May 1968, AT 3:07 AM CET, the SCOUT rocket was launched from Vandenberg Air Force Base in California carrying the European Space Research Organisation ESRO-2B satellite, Europe’s first.

A few minutes later the telex message from the control centre read: “May 17, 02:07 Z lift off confirmed.”

Preparations had been underway at the Tromsø Satellite Station (TSS) for several hours. But now excitement notched up. If everything went as planned, the first signals from the ESRO-2B satellite would be received in about 100 minutes.

The preparations had actually begun in January. Simulations had been run more or less continuously, using data from the final tests of the satellite. We had direct communication lines to the European Space Operations Centre (ESOC) in Darmstadt, Germany, and the simulations had been performed as realistically as possible.

But simulating a satellite flyby might differ considerably from conducting it in practice, not least because this was the first time it had been done. For both the small TSS staff and for the satellite controllers in ESOC, the event was a baptism by fire.

Not only the human staffs were new at it. The ESRO-2B was fitted with a new technology for sending signals to Earth stations. Pulse Code Modulation (PCM) had been developed and tested during the Second World War, but was far from being a routine technology.

At TSS, the PCM gear was connected to a Norwegian-developed digital computer. At the time, TSS was the first station of its kind in world to have a digital computer connected to its decoding equipment.

It was to become a key element in the station real-time services. Named SAM-2, the digital computer had been developed at the Norwegian Defence Research Establishment (NDRE) at Kjeller, near Oslo. It was to trigger the foundation of Norsk Data, but that’s another story.

The small TSS staff had meticulously adjusted all equipment according to ESOC instructions. We had used the nominal orbital parameters to program the antennas, consisting of azimuth and elevation look angles for the first satellite flyby.


The team at Tromsø Telemetry Station was able to celebrate that the first support of a satellite launch from the new station in Tromsø was successful. The world´s most advanced ground station at the time, with a Norwegian–developed computer connected, even before NASA had it.

The look angles were entered into the antenna control unit to ensure smooth movement. The big question was therefore whether they were correct. Would ESRO-2B appear in the sector of sky at which the antennas aimed?

The wait was unbearably long. But Launch Control had reported that the rocket had performed as planned. The tasks at TSS had been specified concisely. Hans Magnar Pettersen was to monitor the receivers; Kåre Amundsen was to check the PCM and telecommand equipment; and my tasks were to ensure that the antenna system functioned and carry out voice contact with the satellite controllers in Darmstadt.

The Station Manager, Dagfnn Leiulfsrud, was of course present, and, as a back-up, so was Roald “Pedro” Pedersen, an expert hired in from the Andøya Rocket Range (ARR) for the initial effort.

The simulations had indicated that the station was considerably understaffed. The critical instant was when ESRO-2B would fly into the antenna beam. The distance from the antenna to the satellite at that time would be about 3800 km. The predicted time to receive the signals, Acquisition of Signal, (AOS), from the satellite was set to be 03:31:00 Z.

The event

The station clock showed 03:25 Z in the telemetry room; the silence was deafening. At the receiver, Dagfinn and Hans Magnar stared at the green line on its display. They would be the first to see a received signal. It was 3:30. Now we were watching the station. It passes 03:31:00, nothing happens!

The antenna starts to move slowly as programmed. Dagfinn reaches for but doesn’t move the adjustment knob on the receiver.

“Has something gone wrong? Have we erred, or…?”

Innumerable questions, but nobody dares answer. This is unexplored ground! Then at 03:31:14 there’s a sound from the receiver, and a spike shows in the green line; suddenly we’ve received a signal from ESRO-2B!

“Tromsø confrm AOS at 03:31:15;”

The message is forwarded to ESOC using voice control.

“Confrm PCM-lock” Kåre reports.

This means that the demodulation gear has locked onto the signal from the satellite. I immediately report “PCM lock” to ESOC and the satellite controller confirms receiving the message.

We have started the first satellite reception and “all systems are looking good.” Now everything happens as simulated for the past months.

The antenna elevation is increasingly higher, and the first command signals are sent to the satellite. This is a critical operation. The satellite battery capacity is limited, so its systems should be started to charge its batteries.

Everything works as planned. The dialogue with ESOC seems problem-free, and all systems are working normally. After some nine minutes, ESRO-2B again nears the horizon, and Tromsø Telemetry Station has completed its first flyby of the first European satellite.

“Tromsø reports “Loss-of Signal (LOS) at 03:40:20” is the final voice message to ESOC. The satellite controller confirms and congratulates.


Station Manager Dagfinn Leiulfsrud gives the “thumbs up” for successful reception of the signals from ERS-2, Europe’s first satellite 17th of May 1968, Norway´s Constitution Day.

Now only a PASS REPORT needs be sent to ESOC. It goes out in a telex message.We congratulate each other upon having taken part in a historical event. Europe, Norway, and Tromsø have entered the space age.

It’s almost 5 o’clock in the morning of the seventeenth of May, Constitution Day, Norway’s national holiday. In a few hours the traditional children’s parades will start. But for the staff at Tromsø Telemetry Station it’s no holiday this year.

The next ESRO-2B flyby will be in about 100 minutes; thereafter it’ll be non-stop.

Legacy

The rest is history. Growth came apace. TTS became Tromsø Satellite Station (TSS) and today, 50 years later, the station is still fully operational, and serves as headquarters for what has become the world´s largest commercial provider of Ground Station Services, tracking both satellites and launchers.

KSAT, Kongsberg Satellite Services owns and operates 20 satellite ground stations round the world, including the two unique polar stations at Svalbard in the Arctic and Troll in Antarctica. Together the stations use more than 140 antennas to receive data from and send command signals to satellites in polar orbit more than 36 000 per month.

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Ove Ronny Haraldsen

Corporate Communication Manager

MOBILE:
+47 99 15 59 20
E-MAIL:
ove.ronny.haraldsen@kongsberg.com

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