Today is Monday, the 21st March 2005, a pleasant evening in the Conference room of the Institute Astronautical Engineering of the Technical University of Munich, and I have the privilege to talk to Prof.Dr.H.O.Ruppe, emeritus of the institute. Professor Ruppe is the author of more than 100 publications in the field of astronautics, including two comprehensive double-volume books; and, before he introduced astronautics to this university, he was head of the "Future Project Office" at NASA's Marshall Space Flight center in Alabama. It is now 22 years ago that I finished my dissertation under his supervision at his institute. His professional help during the following years and many pleasant talks I had with him encouraged me to write this book. Now the book is finally finished, and at this occasion we want to talk about astronautics: the past, the present and the future.

 

Manned Space Flight - glorious past but gloomy prospects 

 

Prof.Ruppe, astronautics is often used as a synonym for manned space flight. When I look at the American Space Shuttle System STS or at the International Space Station ISS, I get the feeling that presently manned space flight experiences a serious crisis. Do you agree with this point of view and, in case, can you explain to us how it came to the present situation?  

 

Ruppe:   Till the end of world war II astronautics was essentially "manned astronautics". At that time automated space flight was thought about but not really. It appeared necessary for all complicated functions to have man aboard. This may be compared to the development of aeronautics which had to do with human flight in machines. Of course there were models, usually from school children, but this was used to initiate the children to the science of flight. In the same way we thought about unmanned flights, for example to the moon, to bring us to human flight to the moon. In this way the Apollo mission followed the thoughts of the oldtimers: man to the moon. Such developed the competition between the two superpowers for a lunar race. Of course the total development was very complex. The then Sowjet Union had wonderful successes in both, unmanned and manned astronautics. The United States experienced a desaster with respect to Cuba. As a consequence, the young president John F.Kennedy  proposed the challenge of a lunar race. The logic was, that the advantage of the Sowjet Union would not be decisive with respect to a manned lunar programme. We - that is the American oldtimers in matters of space - assured the president we could do! So project Apollo was born in 1961. We promised that the job would be accomplished within ten years. As we know now, we did it; the Sowjet Union failed; and the United States preeminence in space was assured.     

 

Apollo was, of course, a manned mission. Every interested citizen could follow such a mission, since its duration was about ten days, a good time interval to capture the interest of a large population. A big question was: what comes after Apollo? There appeared no simple answer. As space station had already been realized both, by the US and by the SU, those were small stations for small crews. So as a follow-on project a large international space station appeared attractive and doable. As a tool for this international station a comfortable and large space shuttle seemed attractive. This tool became a goal of its own; and I think this started the trouble which continues till today. The space station cannot compare to Apollo, and problems with the Shuttle endanger the programme of the ISS.  

 

But how about the manned Mars mission?

 

Ruppe:   President George W.Bush has suggested manned return to the moon and manned flight to Mars. He sees the lunar field as a thought of training ground for manned Mars flights. We also have quite a floury of unmanned Mars missions which followed the Viking missions. So Mars has been much in the news and it seems that we are ready to follow with man. I think this is very wrong. The manned Mars mission probably is the most difficult space mission we could do. Man to Mars is not a somewhat bigger Apollo, instead of weeks it takes years. It is not possible to fly with one vehicle from earth to the target. Instead we have to assemble a Mars fleet in earth orbit and fly from this orbit to Mars. A crew of three may not suffice. I do not think that the lunar training is of much help with the Mars job.

 

Don't you think that a manned Mars mission would be a way out of the present crisis?

 

Ruppe:  Yes, I think so definitely. A manned Mars mission would again put an attractive goal for manned space missions. This would keep us busy for a long time - I think much more than ten years. It is a very attractive chance to help international cooperation.

 

Recently we have seen the privately financed flight of Burt Rutan's spaceship 1 vehicle. Isn't private astronautics another way out of the crisis?

 

Ruppe:   I do not think so. Rutan's vehicle showed us a jump about 100 kilometers high and a few hundred kilometers in distance. Even that is quite expensive; and you cannot develop real space flight from it. The minimum for space flight is in my opinion an earth satellite. To do this you need a step rocket with two or three stages. To return from orbit a capsule of sorts is necessary. We have just to look at American or Russian or Chinese beginnings. That is hundreds or thousands of millions of dollars away from Rutan.

 

The shuttle must be replace one day, maybe even soon if another accident occurs. Isn't a capsule the better solution for manned space flight?

 

Ruppe:   This is a very difficult question. At this time many investigations are under way both at NASA and at United States space industry. There is no clear answer yet. I think the main objective of the new vehicle will determine how the solution will look like. For a lunar landing you cannot use wings. The astronauts told me that they like the comfortable landing in a shuttle. From a reliability point of view I think there are no significant differences between both systems. Until now the shuttle has about 100 flights with two significant accidents. I think that a future shuttle will have better rescue possibilities for the crew.  Presently the capsule has better rescue capabilities - but we have had two fatal accidents in the Sovjet programme. It appears to me that the struggle between capsule and shuttle is about even. It will be interesting to see what the future will hold. Obviously, the winged vehicle is limited to low earth orbit since in space the wings are just ballast and not really useful. Hence, for deep space or lunar environment capsules are the natural solution. Mars may be an exception. Wernher von Braun's first Mars study, ca. 1950, utilized winged Mars landers. You should remember that, at this time, the Mars atmosphere was assumed to be more dense than we learned from Viking!            

 

Launch Vehicles - tools for astronautical activities

 

Well, also for me it is evident that high-altitude airplanes are not the correct way to access space. Twenty years ago I believed that the shuttle was the best and safest option, but today the experience spoils that view. Today I think that conventional rockets are the best opportunity for space transportation. However, in my book I state that it was a bad mistake from the European space agency to take the commercially successful Ariane-4 launcher from the market; and I believe that  the Ariane-5 launch vehicle in its present form is ill-conditioned for the transportation of commercial satellites, particularly because of the application of strong solid booster motors. You worked for more than 60 years on the subject of space launcher optimization. What do you think about the present space launcher situation?

 

Ruppe:  The transport system "Ariane 4" could be adapted to mission requirements by relatively simple modifications of the first stage. This way is not useful for Ariane 5. Here the final stage can be changed by using different propellents - hydrogen or storable. An advanced hydrogen version has been cancelled but is still being talked about. Nevertheless it remains basically the Ariane 5 with associated high transport costs. In my opinion the decision between solid or liquid propulsion is more or less even, at least as it concerns first stages; reasons of availability might be decisive for upper stages. Also there are rumors that in the case of the US-shuttle the solid propellent company "Thiokol" had to be involved. So you see that sometimes the problem of industrial participation might be decisive. 

 

European nationalistic reasons will keep the Ariane 5 in operation, for example for the transportation of military satellites. The space transport picture gets more difficult if the many available systems in US, Russia and China are considered. We can expect survival of only some of the many systems.

 

Application Satellites - a shrinking market

 

Well, then the space launch business is presently in a difficult situation, because the market for satellite services is actually shrinking. But why is this so? The telephone market is booming, television occupies more time in everyday life, and the new GPS navigation system in my car is really a useful device. I nearly never miss the eight o'clock news, particularly because of the weather forecast for the next day. Considering all this, shouldn't we expect a booming satellite business? 

 

Ruppe:   The most important part of application satellites has to do with communications. This market is fairly saturated at present. Only the failed satellites and of course extensions of the system have to be replaced. But I understand that glass fibers with optical communication give a stiff competition to the satellites. So this market may shrink compared to the past. Of course this is all undecided and only the future will tell. Weather satellites pose difficulties of their own. We are quite accustomed that weather surveys and predictions are provided by the governments. So private weather predictions is rare. Military weather prediction falls into the same class: it is not derived from private satellites. The military serve their own purposes.

 

After Global Positioning System we are accustomed to non-pay services. So again the government gives us such satellites and the infrastructure which is required. It is not a private service! Recently there was a big Tsunami in Asia. This lead to the expectation of catastrophy warning satellites. Again, this is no field for private enterprise. I think that the governments should provide this service. Observation of the surface of the earth is a typical task for spacecraft. The military require good resolution in the order of ten centimeters, they have a close supervision of this field. They will do so in all foreseeable future. Because of this, private earth observation is rare.   

 

Scientific Missions - brilliant jewels in astronautics 

 

You often told me that you see the search for extraterrestrial life as the ultimate goal for astronautical activities. Well, up to now we didn't find any aliens in our solar system; but the scientific deep space probes were surely worth the money. How poor would be our understanding of the solar system without them. I am always fascinated when I look at the pictures which the deep space probes returned to the earth, many of them are prettier than a space artist could paint.

 

Ruppe:   I fully agree with what you say. There is a fascinating task to determine how life began. Did it come from space? Were comets important in this respect? How about life on other worlds? Do other suns have planets? I think of earthlike planets and not of giants like Jupiter. Some large planets of other suns have been found but not small bodies like our home planet. Observations from space promise to help; but these satellites have to be much larger than the Hubble space telescope. The Hubble telescope is the largest space observatory which has been launched so far. No doubt there will be more potent successors. In my opinion the never ending task of astronautics is the determination of the human role on earth and all the history of the universe. 

 

Prof.Ruppe, I want to thank you very much for this interesting interview.

 

Ruppe: I'm proud to accompany this fine book with this preface interview. I wish you all success.