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An instrument designed in Romania will measure the first asteroid deflection in a NASA/ESA planetary defence mission

on 21 September 2022

What will happen to humanity if an asteroid hits Earth again? Will we suffer the same fate as the dinosaurs or will we be able to avoid disaster? This year sees the first international effort to deflect an asteroid's trajectory, and Romania is one of the countries contributing to the European component of this mission.

65803 Didymos is an asteroid classified as potentially hazardous, consisting of the main asteroid and its satellite, called Dimorphos. 65803 Didymos is the target of the international AIDA (Asteroid Impact and Deflection Assessment) mission, with its two components: the American DART component that will impact the asteroid's satellite on 26 September 2022, and the European Hera component that will observe whether or not we have successfully deflected the asteroid.

Romania will provide some key elements in the success of the European mission. The Romanian expertise will help Hera to reach the asteroid and measure its deflection very precisely following the impact with DART. It will also support one of ESA's first two deepspace cubesats to approach the asteroid.

You can read here about the "eyes" of the Hera mission without which it could not be properly guided and manoeuvred, developed with the involvement of GMV Romania.

In this article we explore the Hera mission altimeter, which will measure the asteroid's deflection with an accuracy of up to 10 cm. This altimeter was developed with the support of the National Institute for Research and Development in Optoelectronics - INOE 2000.

The altimeter, whose optical design was entirely made by INOE, is the main instrument that will confirm or deny the success of the whole mission, answering the questions: did we succeed in deflecting the asteroid? And if so, by how much was its trajectory altered?

Why deflect an asteroid?

NASA's DART mission is heading towards two asteroids that form the Didymos binary system. NASA's spacecraft will intentionally collide with the smaller of the two asteroids on 26 September 2022 to see if it can alter its orbit.

ESA will then send its own mission to the two asteroids to observe in detail what happened after the impact. The Hera mission will measure the asteroid's mass and composition, analyse the crater caused by the collision and help us better understand the asteroids. In addition to the main satellite, Hera will also have two smaller probes, Juventas and Milani, which will get much closer to the asteroid, to collect scientific data and then land on it.

So far, the scientific community has incomplete information about the asteroids, and the mission is based on theoretical knowledge, not yet validated. Hera and the two probes will send us information about this binary system, helping us to better understand asteroids and find out, for example, what kind of resources are found on asteroids and whether we can use them for the benefit of humankind.

Hera will also measure whether or not the deflection attempt was successful — a method that could help us better manage asteroid risks. To see how far the satellite asteroid has moved relative to the centre of the binary system, the Hera mission needs a highly accurate altimeter.

The success of the mission, measured with Romanian expertise

After the impact with DART, the Hera mission will reach the asteroid and make a detailed survey with several instruments on board. Among these, the altimeter is the only instrument that will be installed on Hera to measure the distance to the asteroid and determine the new orbit following impact. The altimeter is capable of measuring the distance of targets near the satellite from 100m to 15km with an accuracy of 0.1m. It will send a laser beam to the asteroid and a telescope will capture the return signal. Using this method, researchers will be able to calculate whether and how far the Dimorphos asteroid has moved from its original position.

The optical design of the altimeter was entirely developed at the National Research and Development Institute for Optoelectronics - INOE 2000. The participation in the development of a scientific instrument under the coordination of the main contractor, Efacec Portugal, in the context of an international NASA/ESA mission, stands as proof for Romania's expertise, appreciated at European level.

2022 09 INOE Image B

Credit: ESA-Science Office

"INOE is developing much more sophisticated instruments than the one on the Hera mission, but for terrestrial use," explains Dr Anca Nemuc, INOE manager, "The biggest challenge of this project was to adapt our technologies and knowledge so that the altimeter could work properly in the extreme conditions of space."

To qualify an instrument for flight is almost as complicated as to develop an entirely different device. The INOE team had to rethink everything from special materials that had to withstand the shock of space launch and extreme temperature changes, to selecting suppliers with space experience, to testing the instrument's functionality in special space conditions that are so different from those on Earth.

The benefits of collaboration with ESA and Romanian expertise recognised at European level

INOE's collaboration with ESA started in 2014, with the Multiply project, which developed a multispectral lidar. Based on that performance, INOE started to be recommended at European level In 2017, Efacec Portugal, the prime contractor, contacted the INOE team for the Helena project. As part of this project, the team developed the concept and the first miniature prototype for the future Hera mission altimeter, to demonstrate the feasibility of the concept.

In 2021, the PALT project continued the work started with the development of a larger prototype and then the development of the final instrument, which will be launched into space aboard Hera.

In addition to the optical design of the altimeter, INOE has also been involved in the procurement of the parts that are used to build the instrument and their testing.

"As we are involved in all stages of the project, from concept development to building the prototype and then qualifying the instrument for flight,the Romanian team is being exposed to extremely valuable knowledge gained over time by teams in Europe," explains Dr Nemuc. "The Hera involvement has undoubtedly contributed to the consolidation of the expertise accumulated in Multiply and the development of new skills that strengthen INOE's competitiveness in the space field at European level and beyond."

The instrument is currently in the construction phase. Dr Livio Belegante, leader of the INOE technical team involved in Hera, will travel to Portugal this autumn to participate in the final assembly of the instrument and the tests corresponding to this phase. A team of four researchers and engineers from INOE was involved in the Hera mission.

Main image credit: ESA-Science Office