Science and Technology

The future of European space missions goes through the CTN

The newest campus of Instituto Superior Técnico was chosen to establish the Hypersonic Plasmas Laboratory, which studies the re-entry of spacecrafts into the atmosphere

Inaugurated in March last year, it began carrying out tests in July and the final installation of its masterpiece, the shock tube, is expected to begin in summer 2016. The Hypersonic Plasmas Laboratory ESTHER, located at the Campus Tecnológico e Nuclear of Instituto Superior Técnico, is the country’s largest in the area of space research and will, within a few months, have the biggest shock tube in Europe – “the key to ensuring access to space”, explains professor Mário Lino da Silva, in charge of the project.

Passionate about space since childhood, the professor and researcher at the Institute for Plasma Research and Nuclear Fusion (IPFN) started with aerospace engineering before obtaining his PhD in Physics. Now he will lead one of the most important facilities of European space research, built at the request of the European Space Agency (ESA) to test vehicle entry conditions into planetary atmospheres. “This is a critical problem because, for example, in 2003, a spacecraft disintegrated returning to Earth because it had a faulty thermal protection”, says professor Mário Lino da Silva.

“We have already been designing and modelling in this area, now we have an experimental component and that’s great”, says the professor. “This is the only facility of its kind in Europe – it will give support to all the space exploration missions. This is a unique opportunity for us because we will welcome researchers from all over Europe. We will create a competence centre that has a truly international dimension.”

The shock tube ESTHER is composed of two main parts: a high pressure chamber, where the combustion of a mixture of hydrogen, oxygen and helium occurs, at very high pressure and temperature; and a low pressure tube in which the gases, which simulate the atmosphere, are injected (most often terrestrial atmosphere, but it can also be used to simulate the atmosphere of any planet). When the membrane separating the two is torn, the gases that come from the chambers enter the tube at a very high speed (up to 14 kilometres per second), along which there are cameras and diagnostic tools that analyse the “fireball”, which is created as if it were caused by a spacecraft or a meteorite entering the Earth’s atmosphere.

The project came into being in 2010 and, despite suffering some delays (“It started out as less ambitious, but ESA has asked us to develop a bigger equipment”, explains Mário Lino da Silva), the final assembly of the installation is expected to start this summer. For now, they are testing a prototype of the high-pressure chamber “to understand what we need to improve or do differently, not only in the design of the shock tube, but also in the laboratory”, says the professor.

ESA is the main financier for this laboratory that nonetheless “cannot function without the other partners”: “This project deals with various technological aspects and no one has skills for everything. We work with several companies in the aerospace industry as well as with universities from all over Europe”, says Mário Lino da Silva. Ultimately, everyone wants the same thing: to make European space missions possible. “A planetary exploration space mission cannot be developed without a shock tube – this lab replaces the previous one, already decommissioned, which was in Marseilles.”

Some Master’s and PhD students are part of the group that works full-time on the project (through the APPLAuSE program). “Students get the idea that space is an unattainable thing that you can only work on it in large countries, but it is not true. Nowadays, science is, increasingly, made in a network. Small competence centres in very specific areas are created and a small country can have a big impact.”

The Hypersonic Plasmas Laboratory entailed an investment of three million euros, and almost half a million were a contribution of Instituto Superior Técnico and IPFN. “Once I was told: the simple things have all been done because there have always been smart people. Now we have to do the complicated work, and it is expensive and takes a lot of time to do – that is the science of our days”, summarizes Mário Lino da Silva.