Deploy Umbrella to Re-enter
The launch vehicle described as being "The Future of Spaceflight" is presented to the public at an event at Rainbow Beach on the 14th January 1987.
The development of space launchers has usually been shrouded in secrecy; if they were publicised at all, it would only be outline details and glossy artist’s impressions in an official announcement. Although Atlantic’s new rocket will be built to cover specifications laid down in a USAF contract, this new commercial product is very different; it is launched to the world in a show that is more like a rock concert, a loud stage and screen presentation that has rarely been seen in the industry before. Only the supersonic Boeing 7227 was unveiled with so much glamour and hype.
Both BAC's and MDAC's experience in building missiles and upper stages will be used to create a revolutionary new launch vehicle. Both firms also have close links with spacecraft manufacturers, and the new joint venture will allow them to offer a complete space service solution to customers; from design, to launch, to operations in orbit. The joint venture will enter the market with "Delta Star"; an expendable Black Anvil missile core with a Delta-derived upper stage, however the goal is to swiftly move on to a new vehicle; a launcher designed to cut costs, increase payloads and provide a long-term future for the business.
That rocket will be called Hyperion.
Most of the early spaceflight pioneers believed that the only cost-effective way of launching large masses in to orbit would be with re-usable rockets. Von Braun's Mars plans and the early USAF and Soviet moonbase studies all assumed that hundreds of flights would be needed to assemble vehicles in Earth orbit or on the Moon. In Britain, the Jervis Report is best known for providing some of the impetus that led to the formation of the Selene Project, although in fact it also highlighted the need to reduce the cost of launching payloads into orbit, suggesting the possibilities that might be offered by reusable launch vehicles.
Selene never came close to delivered any such thing - quite the opposite in fact - the Constellation Launch Vehicle was undoubtedly one of the most expensive rockets ever built, its development costs only exceeded by NASA's Saturn III. In the practical world of early spaceflight, the urgent requirements for nuclear missiles (by definition, expendable vehicles) took precedence for development, and all the early space launchers would be based on those designs. In the 1970s, NASA broken that mould and built the Space Shuttle, but even then, the partially-reusable design and a series of other issues meant that it was never cost-effective in its designated role.
A semi-reusable launcher could also have been built based on Black Anvil. Tantalisingly, several such proposals had been made in the late ‘60s, with the ambition varying from multi-core heavy-lift versions, to merely recovering the ring of six booster engines. Numerous experiments had been performed using sub-scale models, and in 1967 there was even an attempt to recover the booster ring during one of the missile's early test flights. However, that attempt had failed and interest had waned as it became clear that there wasn't the time or money to build a reusable rocket. Nonetheless, the tests had left a legacy of valuable data in BAC's and Rolls-Royce's archives on what worked, and equally importantly, on what didn't.
Like the Shuttle, all of those concepts would have been only partly reusable; in case of the early Black Anvil-based concepts, each and every launch would still expend an upper stage. Although they are often quite small and low-powered in comparison to the lower stages of a launcher, these stages are by no means a cheap piece of hardware. In fact, it is usually disproportionately expensive as it carries most of the sophisticated kit needed to make the entire vehicle work. Upper stages are not just a set of fuel tanks and engines, they carry the vehicle's guidance system, power supplies, telemetry equipment, flight computer and often need to be able to control themselves while in space - meaning they need a set of miniature control rockets, engine re-start systems, star trackers and all of the sequencing equipment needed to allow them to fly on their own for several hours and then safely deploy their payloads. All these systems are expensive, and for years engineers have struggled to come up with ways of recovering them. The best known of these is of course, the Space Shuttle, which recovers all of this expensive equipment (e.g. engines and controls) along with all the complex systems needed to support a crew. The Shuttle's designers had compromised in a variety of other ways; it couldn’t go beyond low Earth orbit, and the supposedly cheap "throwaway" tanks and solid rockets boosters had proved to be disappointingly expensive. In the 1980s, the Soviets took a different approach - throwing away the upper stage's engines, but recovering the strap-on boosters and the systems of the Buran orbiter.
For years, designers had struggled to come up with a concept for a more traditional reusable upper stage. The aeroplane-like Shuttle works adequately, but that level of aerodynamic complexity doesn't fit well with the large volumes needed to store rocket fuels and it imposes a heavy mass penalty - mass that is deducted straight out of the deployable payload.
In the early 1980s, BAC engineers thought they had come up with a way to bridge the gap by making the wings work on the way up as well as down. Their HOTOL concept would be fully reusable; a stub-winged vehicle equipped with innovative dual mode air-breathing/rocket engines. Ultimately, this reusable Single Stage to Orbit (SSTO) design proved to be far too ambitious, and the programme effectively ended in 1984 while it was still in the conceptual design stage. At much the same time, NASA tried to solve the same problem with their equally ambitious "Shuttle II" concept (also known as the Hypersonic Space Plane) and were rewarded with a similar lack of success; costs ballooned, and the agency wasted three years and nearly $500M in discovering another way to fail to build a reusable SSTO vehicle.
In fact, like the earlier American Atlas rocket, the basic Black Anvil design could do semi-SSTO (if one allows for the jettison of the booster engines) while carrying a payload; on NASA "Mercury" and Selene "Aurora" flights, the rockets did just that. If a Black Anvil core were fitted with a suitable heatshield and control systems, it might be able to re-enter and be recovered. The problem was that the mass of the heatshield and controls would use up almost all of the available payload mass. Even with the latest Block 4 Orion engines, the payload would only be a ton or so to LEO, not adequate for a viable general purpose satellite launcher.
Putting a useful amount of payload into orbit is doable.
SSTO is doable.
Reusable spacecraft are doable.
Doing all three of those things at the same time is tricky, to borrow Deep Thought's use of the word.
America's, Russia's and Europe's best engineers had failed to find a solution, and in the ensuing embarrassment, everyone had shied away from the "holy grail" of a fully reusable launch vehicle.
Now, BAC and MDAC would try again, but their Hyperion would be a slightly less ambitious "almost fully reusable" launcher. Modern computational models, coupled to the experimental results obtained in the 1960s showed that it would be possible to attempt recovery of a Black Anvil-type booster with a reasonable chance of success, while the Orion rocket engines have a service record that is hard to match.
Hyperion will be a two-stage design. The first stage, loosely based on the missile core of Black Anvil, will lift off much as normal, but won't drop its ring of six booster engines. The jettison system will be removed and the engines will shut down in sequence to keep G-loads under control until the stage's fuel is depleted about 3 1/2 minutes into the flight. After burnout, the second stage will separate and continue on into orbit. Meanwhile, the first stage will deploy an enormous flexible shuttlecock-like “Parashield”, which will allow it to survive the dive back into the atmosphere and slow it down sufficiently to allow a safe splashdown in the sea about 500 miles downrange.
Early impression of a Hyperion first stage starting its dive back into the atmosphere
The new upper stage will also be fully recoverable from either low Earth or Geostationary transfer orbits. It will be designed and integrated by MDAC in the US and will use Oxygen-Hydrogen fuel. As with the first stage, the key to recovery would be the novel Parashield concept. With access to far better instrumentation and test data than in the 1960s, the firms have refined their computational and wind-tunnel models to show that their deployable shield design can survive atmospheric entry.
From the outside, the Hyperion Upper Stage (HUS) will look much the same as any traditional rocket stage; a chunky cylinder 260” in diameter, with a single rocket motor sticking out of the base. In 1986, as both the USAF and NASA showed signs of loosing interest in the Space Shuttle and started to move on to developing new launchers, the manufacturers of the Shuttle's J-2R rocket engines were keen to find new markets. The USAF's heavy lift rocket will use a new high-pressure expendable engine, and the other concepts all use either new lightweight motors or solids.
MDAC engineers found that these well-proven engines could be procured on the cheap, and after a series of design compromises it was decided to use a subtly modified version of the engine. With the exception of Orion and the S-3 derived motors used on the Delta rocket, it would be difficult to find an engine in the West with a better pedigree than the J-2. Originally developed for NASA's Saturn rockets, the engine was later adapted into the J-2R, a long-lived reusable motor used successfully on every Shuttle flight to date.
What makes the HUS unique is the structure on top of the LH2 tank. An arrangement of electrically operated struts and ribs will extend from the sides to form a heatshield, allowing the stage to re-enter and land within a few hours of liftoff. The shield will primarily consist of temperature-resistant fabrics held into a broad, curved shape by a series of titanium arms (the "spokes of the umbrella") When deployed, the structure will be over 100' across, giving the now-empty 15 tonne stage a very low ballistic coefficient as it re-enters Earth's atmosphere. Even when entering from an elliptical GTO, the temperatures on the fabric shield will be low enough for it to survive re-entry. As the atmosphere thickens at low altitude, the stage will slow down to about 40 mph - slow enough for small rockets and airbags to cushion the final impact with the surface. Originally proposed in the US in the 1950s, the Parashield concept had never received much serious study until engineers in both Britain and at the University of Florida independently re-discovered it the early ‘80s. Tests using wind tunnels and sounding rockets have since been made in both the UK and USA, with enough success to validate the underlying concept.
MDAC publicity artwork of an Hyperion Upper Stage re-entering
The Hyperion design is described as "almost fully re-usable", as it still expends a payload fairing and interstage adaptor on each launch. It is thought likely that the flexible heatshield will need to be replaced quite frequently - possibly even after every flight - although the high temperature fabrics will be much easier and cheaper to handle than the delicate tiles used on the NASA Shuttle and the Soviet Buran. Once complete, Hyperion should be able to put about 30t into low Earth Orbit, or inject 9t onto a geostationary transfer trajectory, with all of the most valuable components of the rocket recovered after each flight.
The interim "Delta Star" launchers use surplus missiles fitted with the older Block 3 engines. Hyperion will use the latest Block 4 versions, which were extensively re-engineered under the Cavalier programme to include digital engine control and monitoring systems, higher thrust output and a simplified pre-heater design. Initially the engines used will be spares built for the Cavalier programme, and later there are plans for Rolls-Royce to put them back into production, possibly even as a “Block 5” with further improvements. Most of the existing spares are effectively brand new; they have all been test-fired during the construction and qualification process, and have since spent a few years in either a silo or in storage. When used on a Hyperion first stage booster, each of the seven Orions will need to fire for about 200 seconds. Allowing for static ground tests, an engine with a design life of 3,000 seconds should be able to complete 10-12 missions before it reaches the end of its life.
As the project’s backers and their PR consultants had hoped, it is the last 15 seconds of a series of computer-generated launch graphics that does more to boost the profile of the event than anything else. With a view of the vast Rainbow Beach Launch Station behind them, projector screens show the launch complex as it will appear in a few years' time, with the simulation showing a Hyperion rocket lifting off. Behind the smoke and flame is a shape every rocket scientist and space geek knows only too well. Like an inverted trident, another vehicle waits on its pad.
Under the chunky, conically-topped upper stage sit three identical boosters.
