Hisdesat speeds up the race to make its 2nd Earth radar satellite a reality

The company providing secure satellite communications and images to the Government, the Ministry of Defence, the Armed Forces and the intelligence services in Spain and other countries has just started the race to incorporate a second space platform for observing the Earth into its catalogue.  

On the third anniversary of launching Paz, the first Spanish Earth radar satellite, on 22 February 2018, the national strategic services operator Hisdesat has immersed itself in an arduous process to bring to life the replacement for its first-born. 

It is a dual-purpose spacecraft, whose high-quality three-dimensional images facilitate decision-making by senior government officials and provide intelligence and surveillance to the Operations Command, which are passed on in operational guidelines to Spanish military units abroad. But it is also very useful, for example, for border control, natural disaster assessment, environmental monitoring and verifying compliance with United Nations sustainability goals. 

Hisdesat has recently presented a Manifesto of Interest to the Department of Industry, Trade and Tourism, a document that reflects the importance of its Paz 2 project, with which it hopes to obtain the backing of the General Secretariat of Industry and SMEs. One of the advantages to achieve this is that its new electronic radar eye will be able to merge with the data from the satellite information system (AIS) of exactEarth -a Canadian company in which Hisdesat has a stake-, which provides real-time information on the situation of world maritime traffic, an advantage that will differentiate Paz 2 from other similar satellites.

The Ministry of Defence, headed by Margarita Robles, and the Ministry of Industry and Trade, headed by Reyes Maroto, seem to be leaning towards launching Paz 2, either within or outside a National Satellite Earth-Observation Program (PNOTS-2), which does not yet exist. However, the Ministry of Science and Innovation, piloted by astronaut Pedro Duque, confirms that "they are still studying different options, but no decision has yet been taken". 

According to Hisdesat's CEO, Miguel Ángel García Primo, it would be desirable to complete "in early 2022" all the steps to materialise Paz 2. He considers that to be the "deadline" for signing the manufacturing contract with the company assuming the role of prime contractor.  

However, although there are still ten months to go before the end of 2021, there are still some important milestones to be reached. First, the definition of the operational specifications to be met by Paz 2 must be finalised, a task for the EMACON's (Joint Defence Staff) Chief, Admiral Teodoro Lopez Calderón, who will submit the document, once ratified, to the Ministry of Defence headed by Margarita Robles. 

The competent organisation in this matter is the Secretary of State for Defence, where the teams of Head Esperanza Casteleiro and the Directorate General for Armaments and Material, headed by Admiral Santiago Ramón González Gómez, will develop its content and draw up the Feasibility Report. This will set out the different options for obtaining the capabilities that define the operational requirements established by EMACON.  

In the event that all of the above are implemented, it will be feasible to complete production in 2025 and achieve orbit launch "by the end of 2025 or early 2026". In view of the milestones that remain to be achieved, the best possible time to start tackling the development of Paz "is now", says García Primo, when the moment for its replacement is already in sight and Brussels has activated the Next Generation Recovery Fund that supports the Recovery, Transformation and Resilience Plan.

Paz is positioned at an altitude of 514 kilometres, in the same orbit as the German satellites TerraSAR-X and TanDEM-X. All three have equivalent image acquisition capabilities and modes, forming a constellation that allows them to be operated jointly by Hisdesat, the German Aerospace Agency (DLR) and Airbus. 

However, the German platforms' lifetime is also about to expire and Berlin will replace the two with a single platform. Called HRWS-SAR - an acronym for High Resolution Wideband SAR satellite - it has many synergies with the Spanish Paz 2, so both will constitute the Spanish-German radar constellation in the second half of 2020.

But, what will the new Spanish radar satellite look like? While Paz weighs 1.3 tonnes, its successor will weigh " approximately 4 tonnes". Its antenna will also be larger, longer and wider. The current antenna is 4.8 metres long and "for the new one we want to exceed 6 metres". As for the width, the one that flies in Paz is 70 centimetres and "for the new one we want to reach around 1.50 metres". 

This is the consequence of having multiplied the bandwidth of radar emissions fourfold. In the second half of the 1990s, the regulations of the International Telecommunications Union of the United Nations only allowed radar satellites to have a maximum of 300 Megahertz. Today, those three hundred MHz have been exceeded and have become 1,200 MHz. At the technological level, this huge leap requires adapting, for example, electronic chips, power amplifiers and antennas to be able to radiate a signal with such a high signal frequency.

In line with a long-term vision and plans sector, replacing the Paz satellite "was already on my desk long before it was put into orbit in February 2018", recalls Miguel Ángel García Primo. As the driving force behind the national space community, the first Spanish radar satellite "represented an enormous challenge for our industrial fabric, which never had the opportunity to make any satellite-based on radar technology a reality until the second half of the 2000s". 

From the point of view of García Primo - the technical "father" of his advanced X-band antenna - such a complicated and large-scale device was "the greatest technological challenge for Spanish industry in the 20th century". The situation is very different now. The learning acquired has given the Spanish industry "first-rate knowledge", which now enables it to make "the national technological contribution much more important than it was in the past".