Portsmouth, UK

The financial outlay involved in sending a satellite into orbit has prohibited many small organizations from getting involved in the space sector. However, carrying multiple satellites on the same rocket (ridesharing) is now making it much more convenient and affordable for academic institutes and SMEs to send their hardware into space. This means the space sector needs no longer be the preserve of the few large space primes.

One company taking ridesharing to a new level is GAUSS Srl (Group of Astrodynamics for the Use of Space Systems). Based in Italy, GAUSS was spun out from Sapienza University of Rome’s School of Aerospace Engineering and has been involved in the development of microsatellites since the 1990s. Since 2012, it has been serving the space industry as a private company, utilizing proprietary technology originally developed at the university as well as making its own engineering advances. In addition to the design and production of microsatellite hardware, it also undertakes mission analysis for low Earth orbit (LEO), geostationary orbit (GEO), and interplanetary missions as well as various ground-based monitoring operations.

A key objective for GAUSS is to lower the financial investment levels that academic institutes and small businesses must make to get involved in space-related projects. This led to the company introducing the game-changing UNISAT platform in 2013. UNISAT represented an industry first, as it allowed the in-orbit release of third-party satellites. Over the following years, several different UNISAT units have been placed into orbit, with each of them subsequently deploying a series of CubeSats and PocketQubes for educational and scientific research usage.

One of the electronic towers of the engineering model of UNISAT-7, featuring Harwin connectors. (Photo: GAUSS)

This form of ridesharing has made it more convenient and affordable to put hardware into space, with 30-35 percent cost savings being realized compared to other launches. As well as the more attractive pricing, academic institutes do not have to worry about preparing all the documentation for the launch agency or purchasing their own deployment mechanism, as GAUSS can take care of all this. They also have more control on the release timing, orientation, and tracking of their pico/nanosatellite after release — with accurate and safe deployment of each item into a Sun-synchronous orbit (SSO).

With its latest UNISAT project, UNISAT-7, the GAUSS engineering team looked to take the concept to the next level. They needed to increase the payload capacity so that more pico/nanosatellites could be transported into space as well as making more room for additional experimental instrumentation. Central to UNISAT-7’s success would be keeping its construction as lean as possible, as this would allow them to increase the payload.

Flight electronics of UNISAT-7 with the GAUSS breakout Board 1 used to connect satellite subsystems. (Photo: GAUSS)

The UNISAT-7 spacecraft had to be very compact, fitting within dimensions of just 50 × 50 × 50 mm. It would have a total launch mass of 32 kg, with 15 kg of this being allocated to the payload it was assigned to carry into space. It is therefore vital to keep the weight of all the constituent hardware down. To achieve this, it was constructed using an avionics-grade aluminum honeycomb frame fitted with carbon fiber skins. Body-mounted solar cells were then added externally to provide all the necessary power.

To accelerate the development time, the engineers at GAUSS made use of commercial off-the-shelf components wherever possible. These were supplemented by the utilization of open-source hardware that had been specially modified to cope with challenging space environments.

With the UNISAT-7 needing to be in operation for a period of approximately three to five years, all the constituent components had to support long-term operation. Ongoing reliability was therefore essential. Likewise, these components had to exhibit strong resilience to the shocks and vibrations during launch. In addition to coping with the payload demands already outlined, they also had to be compact and lightweight, as there was very little room available.

UNISAT-7 selfie from space. (Photo: GAUSS)

When selecting the connectors to be incorporated into the UNISAT-7, all of the attributes just outlined needed to be covered. After considering products from different vendors, it was clear to the GAUSS engineers that Harwin’s Datamate series would best address their interconnect requirements. These high-reliability connectors would be used for both data and power transmission. They were integrated into the radio communication modules needed for telemetry, the onboard computer, the power conditioning and distribution unit, the electronic power system, the deployer door mechanism, etc.

Harwin’s Datamate and Datamate Mix-Tek connectors are suited for use in space applications and have a long track record in this area. With small footprints, these 2-mm-pitch components take up only minimal board real estate. Tested to 20-G vibrations and 100-G shocks, they can cope with the extreme conditions encountered during launch — with the 4-finger Beryllium Copper contacts always able to maintain a connection to the corresponding mating surfaces.

The contacts of standard Datamate units have a 3A current rating, while Datamate Mix-Tek contacts can deliver up to 40A of current. The ability to withstand temperatures of up to 125 °C, plus low-outgassing properties, are also highly advantageous. A variety of locking mechanisms are available to ensure interconnect retention.

“In terms of both the cost and logistics, our UNISAT platform has real benefits over conventional launching methods for missions that only have limited resources and budget,” explained Riccardo Di Roberto, Engineering Lead for UNISAT-7 at GAUSS. “But to make sure that our missions are successful, we need to have access to robust, high-performance technology. After considering many different possibilities, it was apparent to us that specifying Harwin Datamate connectors solved a lot of our problems. These components provided us with assured connectivity and would be able to cope with the uncompromising conditions involved. As a result, they feature in nearly all of the UNISAT-7 subsystems.

“When investigating possible options, we managed to get a lot of useful information from the Harwin website and this helped us to find the best fit for our particular requirements,” he added. “The samples we requested were quickly received, which allowed us to start work on prototyping almost immediately. We were also able to get useful technical advice from Harwin's technical department as the development work progressed.”

UNISAT-7 was sent into space via the Russian Soyuz-2-1a on March 22, 2021, from the Baikonur launch site in Kazakhstan. Once in orbit, the two CubeSats and three PocketQubes it was carrying (ranging in size from 1/3U to 1U and 1P to 6P) were all successfully deployed and received by their respective owners. These will now execute a variety of different scientific tasks including multispectral radiation and RF analysis, validation of electronic and photovoltaic devices in space, etc. In addition to acting as an in-orbit pico/nanosatellite deployment system, UNISAT-7 will also be utilized for space debris research and in-situ testing work.

Preliminary work is currently underway at GAUSS on UNISAT-8 and the company is also engaged in developing hardware for several upcoming interplanetary missions. The team is confident that these projects will provide opportunities for them to work with Harwin again soon.

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