Three Diamonds

Three Diamonds – Photo: Sky and Space Global / GOMSpace

Three Diamonds is a three-satellite prototype constellation segment operated by Sky and Space Global as a pathfinder for an envisioned Low Earth Orbit constellation of 200 nanosatellites for narrowband communications for various services including Internet connectivity – initially providing services to the developing world and eventually expanding to a global constellation.

Based in London, Sky and Space Global was founded in November 2015 by Meir Moalem and Meidad Pariente. The company has locations in the UK, Israel and Australia.

Through a reverse merger, the company was able to complete an Initial Public Offering at the Australian Stock Exchange for $4.5 million in May 2016. In August 2016, the company signed a contract with Sat-Space Africa for the provision of bandwidth on the three prototype satellites to be launched in 2017 with the expectation of an annual revenue of $500,000 from the three-satellite constellation alone.

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Photo: GOMSpace

Sky and Space Global entered an agreement with Flextronics Israel Ltd for the design, development and production of end user devices for access to the narrowband satellite system. Ayecka Communications Systems was contracted to design and build prototype hotspots that will act like any conventional hotspot and connect mobile devices to the Internet via the Sky and Space satellite constellation.

Furthermore, Sky and Space Global signed a memorandum of understanding with SocialEco Ltd which is developing a low-cost smartphone envisioned to enable digital financial inclusion of 4 billion people in developing countries. SocialEco is looking into the possibility of integrating an SAS app on their phones to connect directly to the Sky and Space network.

A second IPO in November 2016 raised another $7 million and the company entered an agreement with Globalsat for testing and offering satellite services in Latin America.

In architecture, the Sky and Space Global constellation is not dissimilar to the Iridium Network with the exception of vastly different satellite sizes and operational orbit. Per the company’s design, a multi-plane constellation of CubeSats will provide large area or global coverage with inter-satellite links to connect a user on the ground to a ground-based gateway, e.g. for Internet connectivity, or to another user anywhere within the footprint of the constellation. Sky and Space Global plans to use the S- and L-Band frequency ranges for mobile communications coverage, S-Band for the inter-satellite links and S-Band / UHF for telemetry and commands.

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The Sky and Space Global Satellites comply with the standard 3U CubeSat form factor (10 x 10 x 30 cm) and are being designed with low cost in mind, targeting a unit price of $500,000 to enable the company’s planned business model of regular replacement. The satellites are designed for an operational life of five to seven years, however, the intention is to keep them in active service for four years before dropping them into a lower orbit to dispose of them. This will require 25% of the constellation to be replaced each year, corresponding to 50 satellites with the initial constellation.

This regular replacement will also enable new and improved satellite versions to be integrated to full-operational strength in a short period of time.

Blue Diamond Assembly – Photo: GOMSpace

The “Three Diamonds” prototype satellites – Red, Green and Blue Diamond – were manufactured by Danish small satellite builder GOMSpace based on a commercial 3U satellite platform. GOMSpace is also on contract for the initial operational constellation with a contract value of €35 to €55 million covering a period of four years with first deliveries starting in 2018.

Unique features of the planned SAS Satellite Constellation include on-board orbit management through active drag management and a non-toxic and non-hazardous propulsion system on each satellite. This ensures the satellites remain at the proper spacing within their orbital planes even in varying drag conditions, guaranteeing 24/7 coverage for any location within the service area. The satellites employ three-axis attitude control and agile pointing capabilities.

 

The heart of the SAS satellites is a powerful software defined radio that can be reconfigured during flight, giving the constellation the utmost flexibility to respond to changing communication demands and also allowing for in-flight upgrades of the software-driven radio system. Each satellite can hold four simultaneous inter-satellite links, two in-plane links to the satellites orbiting directly in front and behind and two links to satellites in adjacent planes. A novel software system allows the satellite network to autonomously manage itself for optimal routing of data.

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2020 Constellation Vision – Image: Sky and Space Global

Services supported by the SAS constellation include machine-to-machine communications, real-time tracking for airliners and shipping companies, complementary service for cellular networks in areas with poor coverage, point-to-point communications, Internet distribution, various bandwidth services, ad-hoc-disaster and crisis relief, and premium secure services for governments or commercial entities.

The equatorial satellite constellation to be established by SAS will consist of 200 CubeSats with 40 satellites in each of five orbital planes, one located directly over the equator at zero inclination and four near-equatorial planes with proper spacing to create a coverage band spanning from 15 degrees north to 15 degrees south – providing access to 4 Billion people that are currently only poorly connected.

Sky and Space Global is launching the Three Diamonds pathfinder satellites as a secondary payload on India’s Polar Satellite Launch Vehicle in June 2017 and has purchased four dedicated LauncherOne vehicles from VirginOrbit for the deployment of the operational constellation.

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Three Diamonds bridged Communications Demo – Image: Sky and Space Global

The Three Diamonds proof-of-concept mission will test out a number of the satellite’s abilities including point-to-point communications within the footprint of a single nano satellite, point-to-point communications between two satellites with one inter-satellite handoff, the same over a longer bridge from the trailing to the leading satellite with the central craft acting purely as relay, data handover between two or three satellites and store and forward capability in which one satellite picks up a data packet from one location and relays it to another when reaching its location minutes or hours later.

The Three Diamonds, operating in a high-inclination orbit, will be made available for commercial services through Sat-Space Africa and BeepTool LLC. Sky and Space Global holds a license from the UK Ministry of Defence for the use of its UHF frequencies for command and telemetry for the Three Diamonds for operation through 2019 with the option of an extension. The company has also entered a partnership with USSTRATCOM for Space Situational Awareness data provision and conjunction assessments for the safe operation of the large operational constellation.