Space One KAIROS
Japanese private small-lift orbital rocket
From Wikipedia, the free encyclopedia
The KAIROS rocket (カイロスロケット), or Kii-based Advanced & Instant Rocket System,[1] is a Japanese solid-fuel rocket designed to launch small satellites of mass up to 250 kg to low Earth orbit and up to 150 kg to sun-synchronous orbit by the private spaceflight company Space One.[2] It consists of 3 solid fuel powered stages and a liquid propellant upper stage.
| Function | Launch vehicle |
|---|---|
| Manufacturer | Space One |
| Country of origin | Japan |
| Size | |
| Height | 18 m (59 ft) |
| Diameter | 1.35 m (4 ft 5 in) |
| Mass | 23,000 kg (51,000 lb) |
| Stages | 4 |
| Capacity | |
| Payload to LEO | |
| Altitude | 500 km (310 mi) |
| Orbital inclination | 33° |
| Mass | 250 kg (550 lb) |
| Payload to SSO | |
| Altitude | 500 km (310 mi) |
| Orbital inclination | 97° |
| Mass | 150 kg (330 lb) |
| Associated rockets | |
| Comparable | Minotaur I Pegasus Electron Ceres-1 |
| Launch history | |
| Status | In development |
| Launch sites | Spaceport Kii |
| Total launches | 3 |
| Success(es) | 0 |
| Failure | 3 |
| First flight | 13 March 2024 |
| Last flight | 5 March 2026 |
Namesake
Manufacture
IHI Aerospace manufactures the KAIROS rocket at Tomioka Plant in the city of Tomioka, Gunma Prefecture.[4][5]

Launches
Launch site
Launches are planned from Spaceport Kii in Kushimoto, Wakayama, Japan, a dedicated launch site built by Shimizu Corporation.[6][7] This spaceport is accessible from Tokyo International Airport (Haneda Airport) via Nanki–Shirahama Airport in approximately 2 hours and 20 minutes, and from Kansai International Airport in approximately 2 hours and 30 minutes.[7]
First launch
The first launch was planned on 9 March 2024[8] but was postponed because a ship was spotted in the "maritime warning area" set up in waters near the launch pad.[9][10][11] The launch eventually took place on 13 March 2024, but the vehicle exploded five seconds after liftoff.[12] The remains of the rocket and payload fell close to the launch pad, but no substantial damage was found.[13] Space One announced several hours later that the autonomous flight termination system could have activated and ended the mission.[14] On 25 August 2024, the company's director confirmed that a destruct command was issued on the rocket. The AFTS detected a speed and level of thrust on the first stage that was lower than was modeled. Because this was the first rocket launch in Japan that used a flight safety system capable of intervening in a launch without human involvement, the destruct criteria were set to be particularly conservative.[15]
Second flight
The second flight took place on 18 December 2024, which was canceled because of a failed rocket shortly after launch.[16][17] The mission was planned to carry five satellites, including four CubeSats and one microsatellite.[18] These satellites include payloads developed by Taiwan Space Agency, Space Cubics LLC, Terra Space Inc. and Lagrapo, as well as an additional satellite owned by an unnamed customer.[19] The rocket began tumbling during 1st stage burn. The flight was terminated some time after.[20]
Third flight
The third flight of KAIROS took place on March 4, 2026, lifting off from Spaceport Kii at 9:10pm but was also unsuccessful with flight termination measures being implemented at around 70 seconds after liftoff.[21] With this third failure the commercial viability of Space One was thrown into doubt as Japan seeks to increase its domestic launch industry.[22][23]
List of launches
| Flight | Date (UTC) | Payload(s) | Outcome | Remarks |
|---|---|---|---|---|
| 1 | 13 March 2024, 02:01:12 | Rapid Launch Small Satellite | Failure | Vehicle automatically destroyed by its Flight Termination System at T+5 seconds,[14] owing to lower vehicle thrust and speed than intended.[15] |
| 2 | 18 December 2024, 02:00:00 | TATARA-1 PARUS-T1A SC-Sat1 ISHIKI |
Failure | Carried four CubeSats and one microsatellite. Rocket tumbling was observed at T+95 seconds. Vehicle lost attitude control around the time of 1st stage separation.[24][20] |
| 3 | 5 March 2026, 02:10:00 | TATARA-1R SC-Sat1a HErO AETS-1 Nutsat-3 |
Failure | Vehicle destroyed by its Flight Termination System. |
See also
- Interstellar Technologies, another private orbital launch services provider developing orbital launch vehicles in Japan
- Comparison of orbital launchers families
- Comparison of orbital launch systems