Space One's Kairos rocket is a Japanese small-lift launch vehicle developed by Space One, targeting the small satellite launch market. It is designed to deliver payloads of up to 250 kg to low Earth orbit (LEO) or 150 kg to Sun-synchronous orbit (SSO) at approximately 500 km altitude and 97° inclination. Launches take place from Spaceport Kii in Kushimoto, Wakayama Prefecture, Japan.
Comparison to Rocket Lab's Electron
| Rocket | Height (m) | Diameter (m) | Payload to SSO (kg) | Estimated Cost per Launch |
|---|---|---|---|---|
| Electron | 18 | 1.2 | 200 | ~$8 million |
| Kairos | 18 | 1.35 (fairing 1.5) | 150 | ~$9 million |
Kairos adopts a four-stage architecture, with the first three stages using solid propellant and the fourth (upper) stage using liquid propellant. This differs from many competitors in the small-launch sector, which often use two-stage liquid-propellant designs.
Launch History
The first two flights in 2024 were unsuccessful:
- Flight 1 (March 2024): The rocket's autonomous flight termination system activated approximately 5 seconds after liftoff due to underperformance in the first stage.
- Flight 2 (December 2024): The vehicle lost attitude control around 95 seconds into flight, near first-stage separation, following a sensor issue that affected trajectory.
Upcoming Mission
The third Kairos flight (Flight 3) is scheduled to carry five small satellites to a Sun-synchronous orbit. The launch is targeted from Spaceport Kii, Japan, with recent attempts postponed due to weather conditions (latest reported window: March 4, 2026, around 11:00 JST / 02:00 UTC, pending final confirmation).
This mission, if successful, would mark the first orbital insertion by a fully privately developed Japanese rocket.
Livestream
Kairos 3rd Flight Rising Hope Star
Useful links to stay up to date on launches:
Next Spaceflight nextspaceflight.com
NASA Spaceflight nasaspacefight.com
More about Kairos
The Launch Pad: LAUNCH FAILURE! SpaceOne KAIROS | Helicopter View
SciNews: KAIROS launch anomaly