Rocketing into the Future

As a Dutch kid growing up in the early 1980s I devoured the ‘Euro 5’ science fiction series by Bert Benson. They were typical boy’s adventures: in each book a secret team of European policemen had some 200 pages to track down a menagerie of rampaging robots, mutant criminals and murderous scientists hell-bent on terrorizing Earth and the solar system. The bad guys were usually seeking world domination, which they inevitably intended to obtain via some overly complicated but fascinating scheme. As required by the genre, the good guys always managed to arrest the interplanetary villains before they could bring their devious schemes to fruition. Just in the nick of time of course. It was ideal literature for a certain somewhat nerdy would-be aerospace engineer. The books were all written in Dutch, and much later I found out that writer Bert Benson’s real name was Adrianus Petrus Maria de Beer, which sounds about as futuristic in Dutch as is does in English. In spite of this, the stories breathed a kind of cosmopolitan atmosphere, with a diverse team of agents from various European countries (the leader was Dutch, naturally) flying to exotic countries, forgotten islands and hostile moons and planets. Their means of transportation was the Euro 5, a wedge­shaped rocket spaceplane with a set of large wings at the back and smaller ‘canard’ wings in front, four rotating ray-guns, and a small boat-shaped plane for short reconnaissance trips (which I now know looks a lot like NASA’s M2-F3 ‘lifting body’ experimental rocket plane of the early 1970s). In the final pages of each book, it was usually this marvelous machine that saved the day, if not the entire universe. For me this gigantic blue vehicle was really the centerpiece of the stories, rather than the colorful team of international heroes. I guess kids in other countries at the time were reading similar adventure books with rocket planes in a starring role.

To me, part of the appeal of the Euro 5 books was that the idea of a spacefaring rocket plane did not seem to be very far-fetched. After all, when I was reading them the Space Shuttle had just entered service and promised to make all those boringly tube-shaped, expendable rockets obsolete. In 1976, NASA predicted that it would be launching around seventy-five Space Shuttles per year; more than six per month. Because most of the system’s hardware could be reused, launch prices would be lower than for the old-fashioned single-use rockets. The low cost and flexibility of the Shuttle would even make it economically feasible to repair satellites or bring

them back to Earth for major refurbishments. Companies would be able to use the Shuttle to build microgravity factories in orbit, and scientists would be able to fly all manner of experiments and instruments. The Shuttle was going to be everything for everybody, a kind of real-life, American Euro 5. And that would be just the first step in reusable launch vehicle development. Many space experts, members of the public, and for sure a certain twelve-year-old, expected that real rocket planes would soon follow, taking off from normal airports, operating more or less like normal aircraft and flying ordinary people (and even Dutch teenagers) into space.

Like many childhood fantasies, that did not come true. The Space Shuttle proved to be a very complex, extremely expensive and dangerous launch vehicle. Instead of taking off like a plane, a Shuttle lift off is a major event with an enormous checklist of things that can easily postpone the launch if not working perfectly. If you headed to Kennedy Space Center to watch a Shuttle lift off, you could count yourself very lucky if it got off on time. You ran the risk of spending many days at nearby Cocoa Beach, watching a continuous parade of launch delay messages on NASA TV and eating lunches that would likely ground you for being overweight if you were an astronaut. Instead of witnessing two launches within a week, as had been predicted by NASA’s optimistic forecasts of the early 1980s, you were more likely to return home for work and other commitments without having seen even one (ruining yet another childhood dream).

The huge numbers of flights per annum did not materialize mainly because the Shuttle system took much more time than anticipated to prepare for each flight, and because NASA had been extremely optimistic in the number of satellite launches and other missions the Shuttle would be required to perform. Although the Space Shuttle performed some spectacular missions, like repairing the Hubble Space Telescope in orbit, retrieving malfunctioning satellites and putting a large space station up module by module, it did not grow into the cheap, regularly flying ‘space truck’ envisioned in the early 1980s. In fact, during its thirty-year operational lifetime it was the most costly way to launch anything or anyone into space, even without taking into account the costs of new safety measures introduced in response to the loss of Challenger in 1986 and Columbia in 2003.

In his 1986 State of the Union address, only five years after the Shuttle’s debut, President Ronald Reagan already called for a successor, “.. .a new Orient Express that could, by the end of the next decade, take off from Dulles Airport, accelerate up to 25 times the speed of sound, attaining low earth orbit or flying to Tokyo within two hours”. The design for the X-30 experimental precursor of this National Aerospace Plane (NASP) initially looked very much like the famous Concorde supersonic airliner: delta wings on a long and slender fuselage with a pointy nose. However, while Concorde’s maximum speed record was 2,330 km per hour (1,450 miles per hour, 2.2 times the speed of sound), the X-30 would have to accelerate to an orbital velocity almost 14 times faster. Unlike the Space Shuttle, it would not shed rocket stages and propellant tanks on the way up, but would be a true single-stage – to-orbit, fully reusable spaceplane. It was also to be much safer to fly than the Shuttle, which only a few days prior to Reagan’s speech had experienced its first disaster, resulting in the loss of the Challenger Orbiter, killing seven astronauts and throwing the entire program into complete disarray.

Although the X-30 was initially envisioned to use only (exotic and very complex) airbreathing engines, meaning it wouldn’t really be a rocket aircraft, its development would be founded on a long history of rocket plane and mixed-propulsion jet/rocket aircraft experiments. Prior to the advent of rehable, powerful jet engines, rockets enabled revolutionary Second World War fighters to climb quickly and intercept high-altitude bombers. Soon after the war, rocket planes were the first to break the dreaded ‘sound barrier’ and then the lesser-known ‘heat barrier’, establishing them not to be real barriers at all. Then they became the first (and only) aircraft to reach the edge of space, breaking record after record by flying faster and higher than any airbreathing type of aircraft. And large rocket boosters were used to shoot aircraft straight into the air without a runway. Step by step, often involving considerable danger and consequently some disasters, engineers and pilots thus learned how to design and fly vehicles that were part airplane, part missile and part spacecraft. In fact, up until the early 1960s many people expected the rocket plane rather than the expendable ballistic missile to represent the near future of manned spaceflight. The vehicle envisioned by president Reagan therefore appeared to be long overdue.

However, in spite of the impressive aeronautical and spaceflight heritage and optimistic expectations, only a couple of years after Reagan’s speech it became clear that the X-30 as well as its contemporary European and Japanese competitors (the German Sanger-II, the British HOTOL and the Japanese JSSTO), were technically too ambitious and would be extremely expensive to develop. By the mid-1990s all these spaceplane projects had been killed off by alarmingly rising costs and ever mounting technical difficulties.

It now seems that the concept of the reusable spaceplane has reached a kind of dead end, due to a lack of technology breakthroughs, political will and economic rationale. Work on spaceplanes is still ongoing, but at a rather slow pace and at a relatively modest level, and generally with a focus on hypersonic military missiles rather than orbital crewed launch vehicles. The Space Shuttle was retired in 2011, and its currently planned successors are old-fashioned-looking capsules that will be launched on conventional expendable launchers. Also European and Russian plans for new launchers and crewed vehicles focus on next-generation expendable rockets and relatively simple re-entry capsules. This is a very sad situation, considering the long history of rocket plane and spaceplane development, in addition to the huge amounts of time and money already invested in their development.

There is however also some good news. A new industry of companies developing and marketing suborbital rocket planes has recently emerged. Scaled Composites’ rocket plane SpaceShipOne reached an altitude of just over 100 km (330,000 feet) in June 2004, making it the first fully privately funded human spaceflight mission. Less then four months later it won the $10 million Ansari X Prize by flying beyond 100 km in altitude twice in a two-week period. As per the rules of the X Prize, no more than ten percent of the empty weight of the spacecraft was replaced between these flights, making SpaceShipOne a truly reusable spaceplane, albeit a suborbital one. It is also interesting to note that the flight on 4 October 2004 not only earned Scaled Composites the X Prize, but with a maximum altitude of 112 km (367,441 feet) also the unofficial record for the highest altitude reached by a manned aircraft (unofficial because the plane did not take off under its own power). The previous unofficial record of 108 km (354,199 feet) had been set on 22 August 1963 by the air-launched X-15 rocket plane, and thus had stood for over 41 years!

At the time of writing, commercial space tourism flights onboard the larger SpaceShipTwo plane, also developed by Scaled Composites but marketed by Virgin Galactic, are scheduled to start no earlier than 2012. Several other suborbital rocket planes are under development, and there are even plans to run rocket plane races to boost their development and commercial value.

Nevertheless, suborbital rocket planes are a far cry from the large orbital spaceliners we were promised. We can’t yet book tickets for an orbital cruise around the planet on a luxury spaceplane, or fly from New York to Tokyo within two hours as president Reagan announced over a quarter of a century ago. Even the incredible Concorde supersonic jetliner, which during its 27 years of operations notched up more supersonic flying hours than all the world’s air forces together, is no longer flying and there is no successor in sight! In the second decade of the twenty-first century, astronauts are still launched vertically on top of expendable missiles, and planes with rocket engines are only used for suborbital tourist trips. A true rocket spaceplane, taking off under its own power from a runway, using its wings to fly into orbit and then to glide back to Earth for an elegant landing at an airport seems to a remote vision, as far away from reality as it was in the 1950s.

Why is it so hard to develop a true rocket propelled spaceplane to fly us into orbit “the way it was meant to be”, perhaps even doing a playful roll on the way up? And why has the continued evolution of rocket planes, which has been progressing for over 80 years, seemingly run into a brick wall? Is there any hope left for would-be rocket plane passengers and pilots, and if so, what might an operational spaceplane look like? Is Euro 5 ever going to fly? These are some of the questions I will address in this book. In search of answers, but also just out of curiosity, we will journey through history and discover all the wonderful, exciting and weird rocket planes that people have dreamed of, have designed, and in some cases have actually flown (and crashed). Rocket planes have always been at the forefront of technology, pushing the established boundaries of aviation and spaceflight. Because of this they were often highly secret projects, which just adds to their appeal. Whatever rocket aircraft in history you look at, you will always find that at the time it represented a daring leap in technology, and involved much adventure for their brave pilots. Rocket planes were showing a glimpse of the future, even if that future changed continuously and often did not materialize as expected. Hence the title of this book, Rocketing into the Future.

In this book many key technical issues for rocket planes are described, such as how rocket engines work or how the speed of sound varies with altitude. Books on spaceflight of the 1950s and 1960s tended to explain such things, as it was rightly considered that the general public did not know much about such novel technologies. Nowadays not many books and articles about high-speed aircraft and spaceflight bother to explain the technology and physics involved, assuming that readers are either already familiar with or would be bored by such ‘details’. However, to truly understand the enormous challenges facing rocket plane designers, and the often brilliant solutions that have been implemented, some understanding of the basics of air – and spaceflight is necessary. It is certainly possible to explain these without complicated mathematics, as you will see (but you are allowed to skip the passages concerned of course, since there is no exam at the end).

To limit the scope of this book to a reasonable level, I defined ‘rocket planes’ as manned aircraft that use lift-producing wings and rocket power to fly. Spaceplanes that are launched vertically into orbit on top of conventional rockets, without the use of lift – producing wings, and only truly fly upon return to Earth (such as the Space Shuttle) are only described where appropriate; I consider these mere winged gliding payloads rather than true rocket planes. The ‘brute force’ launchers on which such shuttles are bolted ascend almost vertically out of the atmosphere as rapidly as possible in order to quickly escape aerodynamic drag, rather than exploiting the lift-producing capabilities of the air to fly up to high altitude prior to rocketing into orbit; what is called a ‘lifting ascent’. Conventional aircraft that use added rocket boosters to help them to take off are also mostly considered beyond the scope of this book. Unmanned winged missiles and rockets that have small wings only for steering and stability purposes are also only described when there is an important link to the main topic.

There is of course a grey area associated with this definition of a ‘true’ rocket plane. For example, one could argue that the vertically launched Natter interceptor and the Ohka manned missile of the Second World War are not really rocket aircraft; that the ‘Zero-Length Launch’ jet fighters catapulted into the air with the help of huge rocket boosters represent merely an extreme form of rocket assisted take-off; and that the X-30 was not a rocket plane because it used only airbreathing engines. Nevertheless this book does include relatively detailed descriptions of them, in part because they play a role in the overall story of the rocket plane, but also due to the writer’s fascination with these exotic aircraft. This isn’t a very scholarly approach, but this book does not pretend to be an academic report. Similarly, vehicles like the X-20, the Space Shuttle and the Russian Buran also clearly fall outside the main scope, but it is necessary to discuss them in broad strokes because they represent important intermediate steps that link twentieth century rocket aircraft to possible future orbital rocket spaceplanes; in fact, the Space Shuttle has been mentioned several times in this introduction already. Moreover, several early Space Shuttle concepts were actually true rocket planes.

However, even focusing on rocket aircraft that fit my definition requires further selectivity: there is a vast amount of information ‘out there’, certainly enough for a hefty encyclopedia of rocket aircraft. In particular, the assortment of rocket planes designed during the Second World War in Germany, Japan and Russia is simply bewildering. Selections thus had to be made, and this book is not intended to be an all-encompassing database of rocket airplanes: if you are interested in the diameter of the tail wheel of the Me 163 or have an urgent desire to know the liquid oxygen boil-off rate for the Bell X-l, then you will need to look elsewhere. Whole volumes have been written about the individual rocket planes and pilots that are mentioned in the following pages. The aim of this book is to offer a concise account of the amazing history of rocket aircraft, the perseverance of their designers, the bravery of their pilots, the logic of their technical evolution and how they paved the way to future spaceplanes.

Another thing that I quickly found out is that for early rocket planes, say up to the end of the Second World War, it is possible to concisely describe their development, since it was usually short and involved only a few key individuals. But after the war, aircraft and rocket technology increased in complexity so rapidly that large numbers of people and long development times were required; even the initial design became a team effort rather than the work of a single, brilliant ‘lone wolf inventor. The Opel RAK-1 rocket glider for instance, involved three key people and several technicians, and flew a few months after the project was conceived; in contrast the Space Shuttle took over a decade to develop, involved six main contracting companies and over 10,000 engineers, technicians, managers and support personnel. It is impractical to completely describe the entire history of an extremely complex vehicle such as the Shuttle or even the earlier X-15 in only a few pages, and thus the further we move through time, the more I had to focus on a rocket aircraft project’s most important issues and events.

Researching this story has led me to an astonishing wealth of books, magazine articles, websites and technical papers, many of which are listed in the bibliography. Sometimes different sources provide conflicting pieces of information. Faced with such conflicts, I either sought the original source or used what appeared to be most plausible. My search also often led to surprising finds, such as descriptions of truly weird and suicidal designs that thankfully for the pilots never left the drawing table; and websites selling such must-have items as an intricately detailed scale model of a rocket propelled Opel car, and a wooden made-in-the-Philippines model of a 1920s’ spaceplane design (both of which now decorate my bookshelves). I hope the readers of this book will have as much fun and amazement as I had in writing it. Ready for take-off?

Thanks to Shamus Reddin for information on the Me 163A’s RII-203 engine and also for the interesting information on Hellmuth Walter’s rocket technology on his website (www. walterwerke. co. uk). Bruno Berger of the Swiss Propulsion Laboratory provided some clarifications on the Mirage SEPR 844 rocket boost pack. Alessandro Atzei and Rogier Schonenborg accompanied me on two fruitless efforts to witness a Shuttle launch, during which we nevertheless had a lot of fun and saw much of Cape Canaveral and the Kennedy Space Center. My father allowed himself be talked into making a long car ride to see the Soviet Buran shuttle in a museum in Germany. The European Space Agency team of the Socrates study, of which I was part, I thank for all the interesting discussions and information on the design of a rocket plane (even although it never left the Powerpoint stage). To Georg Reinbold, thanks for all the interesting discussions over many years about the costs of spaceplanes and reusable launchers. I thank Amo Wielders, Stella Tkatchova, Ron Noteborn, Dennis Gerrits and Peter Buist for their suggestions and many interesting ideas concerning space transportation, Ufe, the universe and everything. And David M. Harland, himself an accomplished writer, did all the editing required to put this text into shape. And last but not least, a big thank-you to all those writers who managed to tell the stories of many almost forgotten rocket aircraft projects; without their books, reports, papers and websites the ‘big picture’ presented in this book would not have been possible.