Career
Johnston started his career as a software engineer doing high-frequency algorithmic trading, and later returned to South Africa to do venture capital.[13] Later, from 2019 to 2021, Johnston worked as an associate at McKinsey & Company where he worked with national space agencies.[14][15]
In March 2021, Johnston co-founded Opontia alongside Manfred Meyer, a digital brand aggregator focused on the Central & Eastern Europe, Middle East, and Africa (CEEMEA) region.[16] The company's business model centered on acquiring profitable digital brands.[16]
In June 2021, Opontia raised $20 million in seed funding from Global Founders Capital, Presight Capital, Raed Ventures, and Kingsway Capital, along with angel investors including Tushar Ahluwalia, Jonathan Doerr (co-founder of Jumia), and Hosam Arab.[17]
In December 2021, Opontia raised $42 million in a Series A round, making it one of the largest Series A rounds in the region. The round was a mix of equity and venture debt, with STV leading the equity investment.[18][19][20] The company ranked 12th on Forbes Middle East's Top 50 most funded startups in 2021.[21] Opontia was acquired by Perfection in 2023.[22]
In early 2024, Johnston co-founded Starcloud (originally named Lumen Orbit).[14][23] Starcloud is a US–based company that designs, builds, and deploys orbital data centers in space.[24]
Starcloud participated in Y Combinator's Summer 2024 cohort and raised approximately $21 million in seed funding by the end of 2024.[25] Investors include Y Combinator, NFX and In-Q-Tel, and the company is part of NVIDIA's Inception Program.[25] The company rebranded from Lumen Orbit to Starcloud in February 2025.[14]
In November 2025, Starcloud launched its first satellite, Starcloud-1, equipped with an NVIDIA H100 GPU, which the company reported as being 100 times more powerful than any GPU previously operated in space.[26][27] The satellite successfully trained NanoGPT, a large language model, marking the first time an LLM was trained in space.[27][28]
On March 13th, 2026, the FCC accepted for filing, an application by Starcloud for a constellation of 88,000 orbital data center satellites.[29]
On March 30th, 2026, Starcloud announced that it had raised a $170M Series A at a $1.1bn valuation led by Benchmark and EQT Ventures, making Starcloud the fastest unicorn in Y Combinator history just 17 months after completing the program.[30]