Hundred space flights
Interview with Valentin Ivanovich Buzuluk, the Head of Research Sector of Prospects for Aerospace Systems Development, a member of eh K.E. Tsiolkovsky Space Academy of Russia.
Fifty three years ago the first manned space flight took place. There have been many changes since that time: now spacecrafts leave from the Earth on a regular basis, many satellites support communication and broadcasts of TV signals, and space tourism has become an expensive, but quite real entertainment. Previously, the Moon was seen as a distant celestial body with Mars just a bright point on the night sky, and now we seriously consider the possibility to use these bodies for populating, mining, production and other human needs.
Research of spacecraft is one the most important field of TsAGI activities. Our Institute is the only organization in the country and one of the biggest in the world that is capable of simulating, on land, all the complexities of spacecraft flight conditions: hypersonic velocities, acoustic effects, high temperatures, vacuum, etc.
The possibility of rockets/spececraft reuse has occupied scientists in our country and abroad for a long time. An outstanding example of achievements in this field is the Buran orbiter — a reusable space vehicle, which was created with TsAGI playing a key role in its creation. The booster rocket for this space shuttle was designed as destroyable and not reusable.
Today scientists have as a goal the design the orbital injection system as a reusable system. This year TsAGI has completed a series of research activities related to reusable spacecraft boosters (RSB) and their re-entry winged vehicles. This injection system is under development by the Khrunichev State Research and Production Space Center (SRPSC) in co-operation with more than 20 companies of the aerospace industry.
We interviewed Valentin Ivanovich Buzuluk, Doctor of Engineering, a leading TsAGI expert in this field, the Head of the NIO-10 Research Sector of Prospects for Aerospace Systems Development, and associate member of the K.E. Tsiolkovsky Space Academy of Russia. Valentin Ivanovich presented highlights of the system, its advantages and shortages, and described the work done by the large team of TsAGI scientists.
— Valentin Ivanovich, as defined by its name, the orbital injection system can be used several times. How many is this “several”?
— These re-entry winged vehicles are designed for one hundred flights maximum.
— What is the re-entry rocket vehicle? Does it mean that all of the system launched into space should return back to the Earth?
— In general the reusable booster is a two-stage injection system. Only its first stage is “reusable”, that includes one or two re-entry winged vehicles (RWV). The RSB starts vertically, and at Mach number equal to seven (approximately 7000 km/h) winged vehicles of the first stage are detached from it. It takes place at the height of approximately fifty kilometers. There is practically no air at this height, thus the spacecraft initially moves in the free flying mode. When the vehicle re-entries into the Earth’s atmosphere, aerodynamic controls switch on, braking begins and the vehicle turns to the direction of the launching site, from which it was launched with the booster rocket. When subsonic velocity is achieved at the height of about seven kilometers jet-propulsion engines of the re-entry vehicle are activated. The vehicle becomes a real remote-piloted aircraft and performs its return flight in automatic control mode at the speed of
— Where will these vehicles return?
— Currently a new Russian launching site “Vostochny” is under construction in the Far East, in the Amur Region, near the Uglegorsk settlement. It is this site that will be the RSB start point and the return point for reusable vehicles of the first stage. The construction of a five-kilometer-long landing runway is already underway.
— The only returnable part is the first stage, and what will happen with other parts of the system?
— The used second stage will be burnt partly in the atmosphere and fall to the antipode of the launching point on the Earth. For the “Vostochny” launching site this antipode point will be located in the area of the Atlantic Ocean between South America and the Antarctic Continent.
— Why did developers design the first stage of booster rocket as reusable, and not the second stage?
— This is mainly due to economical and environmental reasons. It is the first stage that accepts maximum load in terms of energy, weight, and its manufacturing cost forms the most considerable portion in the total cost of the rocket. In addition, the first stage, unlike the second stage, would fall onto a continental part of the Earth not far from the launching site. Single-shot orbital injection systems require allocation of restricted zones, which are prohibited for living or working because metal, fuel remnants and other wastes pollute soil and air.
— What is the economic gain?
— There is such a term as “specific cost of payload injection to orbit”. It consists of the cost of system development, the cost of system manufacturing and the cost of its operation. The most expensive is manufacturing, and, as you understand, in the case of a conventional booster this part of the cost is repeated with every launch. In the case of a reusable system we can reduce the cost by a hundred times! However, development of the first stage will be more expensive because it will not be just a single-shot rocket part, but a а reusable winged vehicle. Also, the “post-flight maintenance” cost will be added. However, finally the reusable design of the fist stage will allow us to achieve a quantum leap in spacecraft building and save hundreds of billions of roubles.
— What can you say about total efficiency of the system? For example, in terms of load capacity: does this new system correspond to its predecessors?
— It exceeds them by several times! We have considered four options of reusable system arrangement. The most simple option, “1+1”, when the rocket includes one unit of the first stage and one unit of the second stage, is is capable of delivering five tons of payload into orbit. For example, the Proton booster injects into orbit a bit more than twenty tons of payload, while the Soyuz booster can inject about seven tons.
The RSB option with one single-shot unit and two re-entry units is capable to inject thirty five tons of payload, and the option with two reusable units and two single-shot units can deliver fifty five tons of payload into orbit. A maximum load capacity of sixty tons can be achieved by combining two re-entry first stages and three single-shot second stages.
— Why do you create a family of these boosters?
— A rocket launch into space may have various goals: from injection of communication satellites to their orbits, requiring small load capacity, to the building of new space platforms or complex systems that require large capacities.
In fact, the RSB family is a flexible range of orbit injection means that will meet the majority of “space” needs. More over, I’m sure that the RSB family will play the key role in Lunar and Martian missions, because these will require first to inject hundreds of tons of space payload to a near-earth orbit.
— And TsAGI has carried out a large amount of tests in this field?
— That’s right, employees from seven key departments of the Institute were involved in these tests. These activities were generally managed by Igor Kovalyov, the Deputy General Director of TsAGI, and Alexandr Filatiev, the Head of Aerospace Research Programme.
The conceptual design project considered two options of re-entry vehicle : with straight movable wing and with fixed trapezoidal wing. The first RWV option within RSB is a conventional rocket unit equipped with wings, which are pulled out by a wing actuator after the unit is detached from the booster. Before this moment wings are arranged along the body of the spacecraft. The second RWV option looks like the Buran space shuttle modified in accordance with new functions.
A wide range of calculations and experimental studies of the RSB family were carried out in TsAGI. In particular, comprehensive calculations and theoretical studies of all four RSB options and two options of the first-stage winged vehicle were performed by department No. 10. We optimized the main design parameters of the RSB and their orbit injection paths. Concurrently, we have developed new approaches to achieve better characteristics and main parameters of the entire RSB family. We have shown that it is possibly to add from eight to ten tons to the RSB load capacity, while reducing the specific cost of orbit injection by four/five percent. Also, we have found that increasing the number of re-entry vehicles with straight movable wings will allow us to extend the rocket family with load capacity up to one hundred and sixty — one hundred and seventy tons. This will completely meet domestic space industry needs in heavy and superheavy orbit injection means.
We have a lot of things to complete. Scientific research is planned for the year 2015 and development engineering will be continued in the year 2016.
— So, when will the reusable booster will “see the stars”?
— I can tell you that the work performed by TsAGI includes large amounts of research results. They open real scientific and technical possibilities to create a qualitatively new reusable system of orbit injection with winged vehicles of the first stage in the near future. If no obstacles arise and the aerospace industry development is stable, our reusable boosters are to be launched after the year 2020.