SEA STAR TSAAHTO

Orbital Launch Vehicle: The partially reusable Sea Star TSAAHTO rocket is currently under construction at the IOS Mojave facility. It is designed to demonstrate IOS' orbital capability and to serve as a low-cost commercial micro satellite launcher.

Two-Stage-And-A-Half-To-Orbit (TSAAHTO): The Sea Star TSAAHTO is a pressure-fed, two-stage-and-a-half-to-orbit launcher. It has a configuration similar to the Atlas IIA. Half-staging is equivalent to dropping unused ballast. Overall, the TSAAHTO is less complex and therefore safer and more reliable than a three-stage-to-orbit vehicle.

Capability: The standard Sea Star TSAAHTO is designed to place a 45-pound (20.4-Kg) payload into a 150-mile (242-Km)  polar orbit or a 58-pound (26.3-Kg) payload into a 150-mile (242-Km) equatorial orbit.

Components: The three main components of the launch vehicle are the Booster Module (BM), the Sustainer Module (SM), the Satellite Module (STM).

Liquid Rocket Engines and Propellants: The Sea Star TSAAHTO is primarily powered by eight (8) identical, fixed liquid Booster/Sustainer rocket engines and a one (1) liquid Satellite Module rocket engine. Each Booster/Sustainer engine is designed to be throttled independently up to 60 percent to provide pitch and yaw control. A set of on/off thrusters provide roll control. The satellite module is spin stabilized. Storable White Fuming Nitric Acid (WFNA) and Hydrocarbon X (HX) are the rocket’s primary propellants. These storable, environmentally-friendly propellants provide reliable, efficient, hypergolic ignition. The eight (8) Booster/Sustainer rocket engines generate 24,000-pounds (106,757-Nt) of thrust at sea level. A 500-pound (2,224-Nt) thrust liquid rocket engine will power the satellite module.

Click on the picture below to see an excerpt of a Sea Star Booster/Sustainer rocket engine throttling test. The rocket engine nozzle is set to ambient pressure with a maximum thrust of 3,000-pounds (13,345-Nt). Ignition is hypergolic (auto-chemical).

Booster Module (BM): The Booster Module is composed of the four booster engines, the pressurant system,  and their associated subsystems. After approximately 77% of the Sea Star’s propellants are consumed at altitude, the main booster engines will shut down. At this point, the Booster Module is jettisoned. This results in a 44% reduction in the vehicle’s dry weight. The Booster Module is recoverable and can be reused four times.

Sustainer Module (SM): The Sustainer Module includes the Sea Star’s propellant tanks, guidance system, attitude control system, and four sustainer rocket engines. Immediately before booster module engine cutoff, the four sustainer engines are ignited and power the STM until satellite module deployment.

Satellite Module (STM): The satellite module is designed for easy satellite integration. Before the STM is deployed, it is spun like a top to provide spin stabilization. After a coast period, the STM "kick" engine is ignited.

Click on the picture below to see an excerpt of a Sea Star Satellite Module rocket engine test. The rocket engine nozzle is set to ambient pressure with a maximum thrust of 500-pounds (2,224-Nt). Ignition is hypergolic (auto-chemical).

Modular Construction: Sea Star TSAAHTO is primarily assembled from identical modular units composed of a single propellant tank, a valve system, and a single rocket engine. Each modular unit is constructed with state-of-the-art composite and computer technology and incorporates many commercial off-the-shelf hardware components. The modular configuration reduces development costs and is mass-production friendly.

Floating Sea-launch: Sea Star TSAAHTO launch operations will be carried out at sea. Launching a rocket at sea is the most economical method for launching payloads into orbit. It eliminates the tremendous costs and scheduling bottlenecks associated with using the existing land spaceports and airports. Launches can be scheduled according to the customer’s requirements. Other advantages include: 

1)      Launch positions can be selected from a nearly infinite number points around the world

2)       Ocean launch systems are portable

3)       Launch insurance costs are substantially lower

4)       Vehicle recovery operations are simplified

5)       Federal launch licenses are easier to obtain

IOS will stage its launch operations from Port of Long Beach, California. Initial launches will take place from the Pacific Ocean West of Long Beach. 

Maximum Reliability: Most rocket failures are the result of overly complex designs. IOS engineers have simplified the orbital launch vehicle by eliminating unnecessary systems. Turbopumps have been replaced by regulated and blowdown pressure feed systems. The steering system has been simplified by replacing mechanical gimballing by fixed engines with differential throttling. Hypergolic propellants eliminate the need for separate rocket engine ignition system. Storable propellants simplify propellant loading, transport, and stay time. The use of high-density nitric acid reduces the size and weight of the propellant tank system. The IOS rocket systems have been streamlined to the point that the only moving parts they employ are valves.

Minimum Cost: Minimizing the number of rocket systems substantially reduces the cost of both production and development.

Interorbital Systems P.O. Box 662 Mojave, CA 93502-0662
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