Overview of the Aquarius Launch Vehicle
Aquarius is a launch vehicle concept designed by Space Systems/Loral. The Aquarius concept is optimized for launching inexpensive bulk materials like water, fuel, and other consumables that can be affordably replaced in the event of a launch failure. By focusing on low-value payloads rather than expensive satellites, Aquarius aimed to provide extremely low-cost access to space.
The key features of Aquarius include:
- Single-stage to orbit design powered by a single pressure-fed engine burning liquid hydrogen and liquid oxygen propellants
- 43 meters tall, 4 meters in diameter
- Capable of placing 1,000 kg into a 200 km orbit
- Launch would take place from a floating platform in the ocean to reduce infrastructure costs
- Low reliability design to minimize costs
- Once in orbit the payload would be extracted by a space tug before Aquarius deorbits
- Target launch cost of only $1 million; Goal of $600,000 at approximately 100 launches per year
Development History
The Aquarius concept was first proposed by Space Systems/Loral in 1998. An initial technical paper on Aquarius was published in 1999, which included estimated performance and vehicle sizes based on launch simulations.
In 2000, the FAA indicated approval of sea-based launch as long as it occurred outside US territorial waters.
In 2001, the state of California awarded Space Systems/Loral a $110,000 grant to further study Aquarius. This led to a final report in 2002, though no hardware was built.
There was renewed interest in Aquarius in the mid-2000s, when NASA looked into using it for supplying the International Space Station. However, the project was ultimately cancelled due to technical challenges and lack of funding.
Launch Vehicle Design
As a single-stage to orbit vehicle, Aquarius aimed to simplify operations compared to multistage rockets. It would use a single 400,000 lbf thrust pressure-fed engine burning liquid hydrogen and oxygen propellants.
The propellants would be contained in a composite pressure vessel structure. Pressure-fed systems avoid the complexity of turbopumps but require much stronger and heavier tanks.
Aquarius was designed to launch from a floating platform in the ocean, with the payload inserted into a 200 km orbit. A small space tug would then extract the payload and transport it to its final destination, such as the ISS.
Cost Savings Approach
The key innovation of Aquarius is its ultra-low-cost design, targeting launch prices an order of magnitude cheaper than existing vehicles. This is enabled by several cost-saving measures:
- Launching only inexpensive, replaceable payloads
- Avoiding first stage recovery or reuse
- Minimizing launch infrastructure by using floating ocean platforms
- Reduced reliability requirements, approximately 1/3 of launches were expected to fail
- Simple pressure-fed propulsion system with minimum complexity
This low-cost focus would allow Aquarius to serve niche markets, such as supplying bulk consumables to orbiting depots at very low prices.
Feasibility Concerns and Cancellation
While innovative, the Aquarius concept faced questions about its technical and economic feasibility.
Technical challenges included developing very lightweight composite pressure vessels and large pressure-fed engines. There were also concerns about controllability during ascent and achieving sufficient orbit accuracy.
The small satellite market Aquarius aimed to serve was still nascent in the early 2000s. There were doubts whether enough launch demand existed at the $1 million price point.
Ultimately the technical risks, high development costs, and uncertain market led to the cancellation of Aquarius as a commercial venture. However, the concepts pioneered by Aquarius continue to influence low-cost launch vehicle designs today.
Legacy and Future Outlook
Though never built, Aquarius pioneered the idea of ultra-low-cost expendable launchers. While early attempts like Aquarius faced cancellation, maturing technology and launch markets make concepts like Aquarius increasingly viable today. Its legacy lives on as launch companies strive to finally realize the dream of orders-of-magnitude lower launch costs first envisioned over 20 years ago.