This image shows the planned Star-Raker Space Plane, a startlingly ambitious NASA project
that intended to combine airplane and spaceship in an effort to harness the power of the sun.
Pitched by Rockwell International to the U.S. government as a
[QUOTE] "Airbreather/Rocket-Powered, Horizontal Takeoff Tridelta Flying Wing,
Single-Stage-To-Orbit Transportation System," it was hoped that a fleet of Star-Rakers
could launch up to four missions every day, carrying payloads of 100 tons each into orbit.
The incredible lifting power would be necessary to accomplish NASA’s ultimate goal:
a network of 60 space-based solar power stations that would beam enough energy
back down to Earth to power the United States.
An Energy Crisis
The 1970s energy crisis led to the proposal of this spacecraft as the
Western World faced a devastating shortage of oil, widespread panic ensued. As the Yom
Kippur War and the Iranian Revolution disrupted Middle Eastern oil exports,
oil production per capita declined, which exacerbated the world's issue.
The U.S. government desperately searched for alternative ways to fuel the country's energy
grids. The crisis led to NASA considering how the United States could harness the sun's energy,
redirecting it towards Earth. The idea was to build a network of 60
orbiting solar power stations, which would beam down energy.
Each geosynchronous satellite, named Satellite Power Systems or SPS, weighed between 35 and
50 thousand metric tons. The intention was to build two per year for 30 years.
However, the main issue of sending the heavy cargo into orbit every year arose.
NASA couldn't send heavy shipments if the Space shuttle only carried 25 metric tons in low-orbit.
Furthermore, there weren't enough Space Shuttles to routinely carry out the ambitious proposal.
These problems turned NASA to Rockwell's plan for the Star-Raker.
The Rockwell International American winged orbital launch craft was intended as a gigantic heavy-lift
ramjet. Using horizontal takeoff, through a ramjet and rocket, it could doubly land horizontally.
The proposal called for the vehicle to be a single-stage
craft with the capacity to cruise atmospherically.
Design Requirements
Rockwell began toying with the concept of such futuristic technology in the late 1960s.
Their research informed Mach 6 turboramjets, which sufficed for advantageous horizontal
takeoffs and landings. However, while the benefits could be applied to two-stage-to-orbit designs,
single-stage-to-orbit vehicles only see marginal increases in performance.
The idea would be revisited in the 1970s, with members of Rockwell International convinced
that new materials and the wet wing design could make their plans a reality.
The design was intentional, hoping it would serve as a spacecraft. The lower wing loading was meant
to keep reentry temperatures multiple degrees lower than what the Space Shuttle underwent.
The breathable engines were intended to carry significant weight since they
integrated Boeing's concept of a Reusable Aerodynamic Space Vehicle all-rocket HTHL
SSTO. Yet, Rockwell's Star-Raker craft was designed with a 45%
higher dry mass than Boeing's idea, which initially exposed it to more aerodynamic heat.
As for the intended massive payload of Solar Power Satellites, the company investigated the
operational requirements extensively. A significant gamble around giving the
vehicle a turbofan, which would also serve as an air-turbo-exchanger and an HTHL SSTO ramjet,
was placed. The airbreathing HTHL SSTO concept matched the idea of high fly rates
better more than vertically launching vehicles. The Star-Raker needed two aircraft maintenance
buildings, intended to have a quick turn around time of about two days. Although the prospect
of landing at an airbase gave the craft a higher chance of safe return and retrieval.
The risk of damage upon landing was significantly higher than that of a typical aircraft.
Each specially constructed runway could hold a fleet of 30 craft.
The launch range required an extensive field of 850 kilometers or 528 miles.
Rockwell International calculated that each kilogram of payload sent into low orbit
would have a cost of around 22 to 33 dollars in 1978.
To facilitate takeoffs and landings, they wanted their Star-Raker to be compatible with the cargo
handling facilities and airports used for the C-5A Galaxy, Lockheed's military transport aircraft.
Engine thrust capped at 623 kN per ramjet. No shortage of ramjets, the craft had ten.
It would also have three Space Shuttle main engines, each providing 4750 kN of thrust.
The Star-Raker
The Star-Raker, designed but never constructed,
prepared to fly from airport to spaceport for oxygen and hydrogen fuel,
and then head into space on a horizontal take off using its powerful array of engines.
The flight plan laid out in a 1979 technical article, specified a cruising altitude of
45,000 feet. After that, a downwards dive to 37,000 feet would break the sound barrier.
Reaching up to Mach 6, the aircraft would then shoot itself back up
to an altitude of 29 kilometers or 18 miles (95,144 feet).
Each aircraft of this elk carried 100 tons in payload,
shuttling day-in and day-out to place Solar Satellites and other materials in orbit.
Astronauts flying the spacecraft hybrid were to assemble and install the satellites themselves.
Its ten ramjet engines were hydrogen-fueled for supersonic flight, as was their rocket engines.
The aircraft would take off with 1,826 metric tons of liquid oxygen and hydrogen for a safe voyage.
A Worthy But Unrealized Project
Physicist Robert G. Jahn stated the following in the foreword to an 1980s SPS feasibility Report,
[QUOTE] "The SPS is an attractive, challenging, worthy project,
which the aerospace community is well prepared and able to address,
[it]...left the clear impression that if some persuasive constellation of purposes...should
assign this particular energy strategy a high priority, it could be accomplished."
During his April 18, 1977 speech, Jimmy Carter said the energy crisis was [QUOTE]
"the moral equivalent of war." He likewise expressed a need for the United States to move
away from fossil fuels, saying, [QUOTE] "We must start now to develop the new,
unconventional sources of energy we will rely on in the next century."
Ultimately, the project never materialized. By the end of the 80s, Rockwell International was sold,
its valve and meter division going to British Tyre & Rubber. Up to that point,
Rockwell was NASA's number one defense contractor. However, the loss of Rockwell's founder and
the expected peace following the fall of the Soviet bloc forced the company's dissolution.
The Star-Raker fell into the archives of history alongside the dream of Satellite Solar Power.
Nevertheless, the possibility of a similar concept remains
and may be required to address humanity's climate change crisis.