Every time ISTSat-1 passes over Oeiras, regardless of the time of day, there are always people working at the Satellite Tracking Station (ERS-IST), of Instituto Superior Técnico – Oeiras campus, trying to decode the signals sent by the satellite to Earth. Particularly at night, when electromagnetic noise is very low, the Técnico researchers have successfully decoded several telemetry data. This has brought good news: the antennas have opened correctly; the algorithm that “stabilises” the satellite’s rotation after launch is functioning as expected; the solar panels are operational and the battery is charged; the temperature of the various systems, although low (around 4 ºC), is in line with forecast. In addition, commands were successfully sent to the satellite and it responded appropriately. “This information indicates that ISTSat-1 is stable and, overall, performing as expected”, explains João Paulo Monteiro, a researcher at Instituto Superior Técnico.

The only thing that needs to be improved is the strength of ISTSat-1’s signals, which have been arriving on Earth weaker than expected. “The low power of the signals received suggests that there may be problems with the satellite’s transmission”, explains João Paulo Monteiro. “The ISTSat-1 team is now focussing on finding solutions to improve signal reception, either by installing antennas with higher gain on ERS-IST or implementing error correction algorithms in decoding”, he adds. These solutions will be tested over the next few weeks and it is expected that it will be possible to resume the satellite’s nominal operation. It will then be possible to test its ability to detect the presence of aircraft in remote areas. After successfully launched into orbit by the Ariane 6 rocket on 9 July, ISTSat-1 is in a low circular orbit 580 km from Earth.

From the launch of Ariane 6 to the first ISTSat-1 signals received on Earth

On 9 July, at 8 p.m. (Lisbon time), after years of delays and anticipation, the European Space Agency successfully launched the Ariane 6 rocket, which carried ISTSat-1, the first satellite built entirely in Portugal at Instituto Superior Técnico. Minutes after the launch, ISTSat-1 was deployed into space and established its orbit at an altitude of 580 kilometres.

“After the launch, it was quite challenging to locate ISTSat-1’s signals. Eight satellites were launched at the same time, and since there was no precise information on where to find ISTSat-1, tracking it required a lot of patience”, says João Paulo Monteiro.
A few hours after the launch, the team received the news they had been waiting for: a Belgian radio amateur heard and recorded the first signal from ISTSat-1, which was the satellite’s beacon – a Morse-coded signal that provided limited information but made it easy to locate the satellite. The following day, ERS-IST also managed to detect the same signal. Although the signal was weaker than expected, it confirmed that ISTSat-1 was “alive” and in orbit.

In the following days, the information on the satellite’s location, provided by the North American Aerospace Defense Command (NORAD), became more precise. After making some adjustments to the equipment, ERS-IST was able to receive the first digital telemetry signals from ISTSat-1. In addition to the work carried out by Técnico researchers at the satellite tracking station (ERS-IST), several national radio amateurs have been tirelessly helping ERS-IST to monitor ISTSat-1 and have also been able to hear its signals.

The moment ISTSat-1 is deployed into orbit (ESA Twitter):

It’s been two weeks since the historic inaugural flight of the Ariane 6, and this just in – we received the video from our friends at #YPSat of our CubeSats being deployed! 🚀

Take a look as the @Exolaunch deployer first releases ³Cat-4, then ISTSat-1 into orbit. Both of these… pic.twitter.com/CYjEbALCE2

— ESA Education (@ESA__Education) July 24, 2024

ISTSat-1 is the first university satellite entirely developed and built in Portugal. It involved many hours of work and the contribution of around 50 people. It is estimated that more than 20 master’s theses have been written on this topic. The project required overcoming several demanding development stages, after being one of the projects chosen by the European Space Agency (ESA) for the “Fly Your Satellite!” program.

Entirely built by Técnico students and professors, except for the solar panels, this 10/10 cube – with 10 cm edges – internationally standardized unit size for these types of devices – explores the potential of nanotechnology in electronics and carries five boards. Four of these boards are part of a platform and are required in all satellites. They all have a computer, one of them is the so-called satellite payload – responsible for the mission – and the rest are part of the power platforms, which include the on-board computer and the communications subsystem.

The project is coordinated by Rui Rocha, a Técnico professor at the Department of Electrical and Computer Engineering (DEEC), a researcher at the Instituto de Telecomunicações (IT) and one of the founders of IST NanosatLab.

*The project had the financial support of Técnico, Instituto de Engenharia de Sistemas e Computadores, Investigação e Desenvolvimento (INESC-ID), Instituto de Telecomunicações (IT), and the Mechanical Engineering Institute (IDMEC). A team of researchers at the Institute for Systems and Robotics (ISR-Lisboa) and several companies linked to the sector also participated in the project. The NanosatLab consortium is led by INESC-ID and coordinated by Rui Rocha (IT) and Gonçalo Tavares (INESC-ID).