Engineering degree, or how to get a piece of Mars to Earth
Introduction h5>
"State Examination Commission decided to put a rating of" excellent "and the title of engineer." That's how I began Jan. 21 izhenerov in "Spacecraft and boosters».
In this article I want to talk about his thesis project, "Apparatus for lifting the soil from the surface of the planet." The planet Mars has been selected and the spacecraft was created specifically for this planet.
To begin to clarify what a thesis project that makes the student-student and as a result it looks.
In the beginning h5>
Work begins with getting the job. I have nothing interesting had not occurred and the job had to ask the research supervisor. So was the theme chosen for the award. So, the task: to fly to Mars; go down to the surface, taking with him a rover; use inflatable braking device; use the manipulator arm; capsule with soil samples to fly into orbit; return to Earth.
One person to master all in a few months is unrealistic, therefore, taken any part, for example I have: the descent to the surface and take off. Furthermore, all payments, except the special part is taken as a first approximation (ie, approximately).
Composition diploma:
1. General. This section describes the spacecraft and its systems, alignment, justification, mass summary.
2. Special part. A detailed calculation or a detailed examination of any part or parts of the spacecraft.
3. The design part. Calculation of the structure or parts. Mandatory consultation with the teacher, required his signature.
4. Ballistics. It is usually not isolated in a separate part, included in the total. You can consult with the teacher.
5. Technological part.
6. The economic part.
7. Occupational safety.
The latter three also require mandatory counseling and signature.
Crowned by the signature of all the signatures of the reviewer, and then given tolerance protection.
Here is a brief overall view.
Certificate h5>
When tasks are clear design begins.
The first thing I started - this arrangement. The first step was to define constraints.
Inflatable braking device - the development of NPO. Lavochkin. By analogy with the prototype (demonstrator) and found a lot of screen size. Stopped on the weight of 1500 kg. Subsequently, the mass was increased to 2000 kg: mass of the entire spacecraft, including the rover and the recovery vehicle. The diameter of the screen got about 8, 5 m. The central part, which takes the critical thermal loads - metal.
To determine the size, shape and weight of the recovery vehicle had to be considered ballistics. At the department gave a program that considers the rise. The orbit on which the migratory module 400 km - orbit around Mars. To put into orbit a payload of 150 kg (that dock with the migratory module and go to the Earth) must be 1,000 kg of fuel. At this stage and had to increase the total weight of the spacecraft up to 2000 kg, as well as limit the weight up to 500 kg rover (originally planned to take a lot of, like Curiosity).
That Define the first frame.
Fuel took a two-component high boiling point. Fuel: unsymmetrical dimethylhydrazine. Oxidizer: nitrogen tetroxide. Oxygen, and the more hydrogen is not considered due to their properties quickly evaporate. A flight is supposed to Mars long.
Chose the propulsion of the existing ones. One main engine and four engines for orientation. Due to lack of traction engines orientation had used for lifting.
Depending on the ratio of the fuel / oxidizer tanks of fuel volumes considered. Diagram of the recovery vehicle was chosen as the "Frigate" 4 tank with fuel, 2 compartment with the hardware. Also on the recovery vehicle added docking assembly manipulator malonapravlennye 2 (non-directional) antenna. 3 tank pressurization with nitrogen.
Let me explain: In the conditions of weightlessness fuel, as well as any liquid is collected in the balls and balls. Start the engine with fuel in this state is impossible. Therefore invented in tanks put an elastic membrane. On one side of the membrane is pumped fuel which fills the entire tank. On the other hand presses the gas from the tank pressurization, thereby keeping the fuel under constant pressure, and not letting it gather into a ball. Gas in the tanks at high pressure turbocharging many atmospheres.
The recovery vehicle is attached to the frame through the transfer compartment in which the rover should be located. Compartment itself is attached to the inflatable landing gear. In the expanded state of the inflatable landing gear has the form of a torus (donut shape - a bagel). Finally, the mounting device is attached to the brake device.
Description of the spacecraft. Drawing on a piece of technology.
Here is the circuit:
1. The spacecraft during descent, inflatable braking device is disclosed.
2. On a surface.
3. Return the unit.
The special part is combined with the design. This section was engaged only at the end. It was necessary to find the same cylindrical compartment rover made of composite material. But I could not find a more or less clear methodology of calculation, until he came to the electronic version of lectures, where he was even an example. Material was taken CFRP. Communication - epoxy resin. The shell is obtained by winding on the mandrel. Were taken some values of loads, material properties and calculate the thickness of a cylinder with a safety factor.
Safety factor for automatic machines is 1, 1 - 1, 3. For manned missions 1, 5. It is in many times increased thickness of materials of various units, which were counted from the conditions of maximum loads.
Next, I started ballistics. Extraatmospheric considered part of the descent manually from the textbook. The rest of the multiple programs. On the basis of the data were graphed overload, thermal loads, range and other sites on the descent and ascent.
During the descent a few hundred meters to the surface of the screen reset the brake. Simultaneously, the mounting device is inflated. In order not to "land" on the screen is thrown, the spacecraft makes a small maneuver, flying away to the side.
Inflatable braking device has its own instrument compartment. The recovery vehicle and its more complicated.
On the surface, the device works only on-board batteries which are charged immediately before undocking from migratory module.
Soil collects rover. After receiving the capsule comes off. During recovery after a reset time boosters, as already craving need less. Without the engine can be put into orbit a few extra pounds is not. After reaching orbit by a manipulator made soft docking with the migratory module. And then a long way back.
Protection was on the question of descent capsule to Earth. Answer. Capsule fires back from the orbit of the Earth in the direction of our country. The capsule has its own heat shield and parachute system. After landing starts beacon on which we find it, and.
By the way, we can bring the soil up to 3 kg.
Technological part of all similar. It examines the manufacturability of designs, details the division (see. Above), the choice of materials is carried out, the type of joints, the circuit assembly. Yet each is described by its manufacturing process. In my case assembly (welding) spherical tank. I also found the existing fixture for welding. Simply put, a stationary welding machine. So separately develop the device is not necessary. Drawings on it found semi-finished.
According to the technology, as well as in design, the teacher writes a review. These reviews also play a role in the evaluation of the diploma committee.
OSH described harmful fakory affecting humans. In my case, again, when welding. And describes measures to prevent and reduce these harmful effects. Someone found a small settlement ventilation. Inserted in this section. Not turned over.
In the economic part assesses the costs of R & D (research and development), drawn network diagram with all the design work. Naturally costs are untrue. It do not pay attention. Pay attention to the roadmap and all the calculations related.
Briefly say that roadmap - a graphical representation of the work, the time spent on these activities, which work can be carried out in parallel and at what stages.
That's all. Common types and sizes can be estimated from the drawing. It is assumed that the spacecraft will launch vehicle Proton. As the Transfer module conventionally depicted Breeze upper stage.
Finally h5>
Of course, something he took from other diplomas, something with a classmate exchanged. But the work was done. R & D is also interesting. Wanted something really interesting to create, use all their knowledge. And I think I did it.
