The archive · Space, Robots, Defence · Technical decision · 2022–2026
Unastella's electric-pump rocket bet: UNA EXPRESS-I flew from Korea, $44M raised
Seoul rocket startup bets simpler electric motor pumps beat turbo pumps to market: UNA EXPRESS-I flew in May 2025, $44M raised by June 2026.
Unastella
What the business is
Unastella is a Seoul-based rocket startup designing kerosene/liquid-oxygen launch vehicles with electric motor pumps, targeting 400 kg-class smallsat launches to low orbit and, later, crewed suborbital flight.
Starting capital：Total ₩61.5B (~$44M) as of 2026-06-01; Series B of ₩33.5B (~$24M) led by Altos Ventures with Korea Development Bank, Strong Ventures and Hana Ventures.
How it started
Founder Jae Park spent his career on rocket engines: combustion systems for Korea's Nuri rocket at KARI, then the German Aerospace Center, then another Korean rocket startup. He founded Unastella in Seoul in February 2022 to be a commercial launch company, not an R&D group.
What happened
The company test-launched UNA EXPRESS-I from its own Goheung site at 23:50 KST on 2025-05-28 — its first end-to-end test of design, manufacturing, ground ops and flight data. KARI transferred electric motor pump technology and advised the team; Korea's space agency flew components on the rocket. In June 2026 it closed a ₩33.5B (~$24M) Series B led by Altos Ventures, taking total funding to ₩61.5B (~$44M).
How it ended up
Still running: UNA EXPRESS-II is targeted for 2027 with the goal of passing 100 km altitude, which CEO Jae Park says would open partnerships with Korea's major aerospace and defense firms.
Background
Unastella is a Seoul-based rocket startup building kerosene/liquid-oxygen launch vehicles with electric motor pumps, aiming at 400 kg-class smallsat launches to low orbit and later crewed suborbital flight. Its bet is that a simpler, cheaper engine architecture gets a small Korean team to market faster than trying to match the most impressive rocket technology.
Founder and CEO Jae Park had worked on combustion systems for Korea's Nuri rocket at KARI, then at the German Aerospace Center, then at another Korean rocket startup before founding Unastella in February 2022. The company chose kerosene/LOX propulsion and swapped the traditional turbo pump for an electric motor pump — an approach Rocket Lab had already validated in flight. The tradeoff is payload, but Park said the goal was commercial launches, not the most impressive rocket.
On May 28, 2025, Unastella test-launched UNA EXPRESS-I — 9.45 m long, about 2 tonnes, with a 5-tonne-thrust engine — from its own launch site in Goheung, Jeollanam-do. It was the first end-to-end test of the entire system, and Korea's space agency flew components on board. In June 2026 the company closed a ₩33.5 billion (about $24M) Series B led by Altos Ventures, bringing total funding to about $44M; it still had no revenue.
What has to be true
- Electric motor pumps cut engine complexity and cost, letting a 22-person team build and fly its own launch vehicle instead of buying expensive turbo-pump hardware.
- Proven kerosene/LOX chemistry de-risked the engine so the company could spend its energy on speed and integration rather than fundamental R&D.
- Keeping design, manufacturing, ground ops and flight data in-house made the first launch a complete system test that investors could actually see.
- KARI technology transfer and space-agency payloads gave the young company institutional credibility that helped close the Series B.
What can be applied
When your constraint is time-to-market, choose the proven-enough component over the most impressive one: a heavier electric pump that flies sooner beats a lighter turbo pump that flies later.
Aftermath
As of the June 2026 TechCrunch report, Unastella is a 22-person company with no revenue yet, preparing UNA EXPRESS-II for 2027 with a goal of passing 100 km altitude — a milestone CEO Jae Park believes will unlock partnerships with Korea's major aerospace and defense firms. Its first launch was a suborbital test; no Korean private company has yet achieved a commercial orbital launch. Competitors Innospace and Perigee Aerospace are also in the race, while Hanwha Aerospace took over the government-built Nuri rocket.
Sources
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