Tim Furniss/LONDON
Rotary Rocket Company has raised $17 million from investors and hired Barclays Capital to assist in an additional $20 million private investment in its bid to offer commercial satellite launches.
The Redwood Shores, California-based company will offer transportation of payloads weighing 3,200kg to low earth orbit (LEO) by 2000, at a cost of just $7 million - or $2,200kg per kilogramme. Rotary aims "-to herald the arrival of a new space age - the age of routine, commercial space transportation". Its fleet of rapid-turnaround launchers, called Roton, will be the world's first single-stage-to-orbit (SSTO), reusable commercial boosters - and they will be piloted.
The company's name refers to the rotary pumping action of its RocketJet engine and free-spinning helicopter-style blades that deploy for landing. It may sound like fantasy but this is serious. Rotary has the startup funds, employs 60 people at Redwood Shores and has started production of a $5 million research and development plant in the Mojave Desert, near Edwards AFB, California. Sections of the Roton's fuel tank, a major part of the 20m high, 6.7m diameter booster, are being produced at the Scaled Composites factory in Mojave.
COMPOSITE MATERIALS
Composite materials will be used for most of the parts and are simply and quickly replicated from inexpensive moulds. Successful test firings of the hydrogen peroxide and hydrogen peroxide/methanol thrusters for the Roton's reaction control system and the rotor tip thrusters for powered landing have been carried out at Mojave. These propellants have been selected over hydrazine-nitrogen tetroxide because they are safer and not so toxic. The Roton's 500,000lb (2,225kN) thrust RocketJet rotary altitude compensating engine uses centrifugal force to spin kerosene fuel and liquid oxygen oxidiser out of dozens of small combusters arranged in a ring pattern at the rocket's base.
The simple design eliminates the need or heavy and expensive turbopumps. Successful tests have been completed of RocketJet engine components, including the combuster module and igniter. The engine will have groups of these arranged on the periphery of a rotating hub to provide the thrust. The tests were made at the company's own three test stands near Mojave civilian airport.
The Roton lands gently and precisely using helicopter style rotors which are folded flat against the vehicle's sides during powered flight. They are deployed during descent, for piloted landing. The company has completed its Rotor test stand at Mojave.
The whirl stand, as it is called, will be used to measure the performance of the tip thrusters integrated into a set of modified 8.5m-long blades of a Sikorsky S-58 helicopter. After testing, the modified blades will be attached to the S-58 and flown to simulate approach and landings. Rotary took delivery of the S-68 in April.
The rotor development programme will run in parallel with the main engine development, to allow the engineering team greater flexibility and result in a rapid, cost effective development. The company is on schedule for an approach and landing demonstrator atmospheric test vehicle flight early next year.
The powered rotors will be used to "bunny hop" the craft to altitudes of between 5,000ft (1,525m) and 8,000ft for test flights. A rocket powered test flight is planned for late 1999. The test programme will begin "-with a couple of vertical hops before we head for orbit", says the company's chief executive Gary Hudson. The Roton could also fly from various parts of the world, rather than a single site.
PILOTED BY TWO
The Roton will be piloted by two crew during all development and operational flights, housed in a cockpit towards the rear of the vehicle, rather than the front. A flight test team is being recruited from experienced graduates of military and civilian flight test programmes, who "will be familiar in handling the latest high performance air and rotorcraft", says Rotary. The company believes that being piloted, the Roton will be safer to operate.
Airliners have multiple engines and so does the Roton. Airliners can return to land in the event of emergencies, which the Roton will be able to do. The Roton has redundant control systems like an airliner. Although it is highly automated like an airliner, the crew can quickly intervene in the event of a systems failure. Roton also carries one fifth the amount of kerosene that a Boeing 747 does and can land within a 30m2 (320ft2) target, rather than a 747's long runway.
The Roton will be targeted initially at the burgeoning market for deploying constellations of LEO mobile telecommunications satellites and "-we will offer commercial service to LEO during the first half of 2000, with cargo deployments and cargo retrievals", says Hudson. "Follow-on market opportunities for the Roton include solar power satellites and space manufacturing of new materials," Hudson adds. As it is piloted, the Roton will be able to be used to conduct the final satellite check before the release and to return the payload if there is a problem in orbit. If there is, the launch would be repeated for free.
The Roton will also offer rescue missions to repair or retrieve damaged or "dead' satellites. Hudson believes that this will lead to much lower insurance costs for the customer. Launch payment will be received upon successful delivery of the payload into orbit, having been placed in an escrow account by the customer, rather than the client having to pay a non-refundable advanced payment, as is the case with other commercial launchers.
Source: Flight International
