Before understanding path decision of the rocket we need to understand deep space network(DSN). Deep space network is space communication network use for information transfer, controlling and many others. Every organization has independent space network frequency. they use separately for own spacecraft. The image sent by satellite or robots are not in the image(digital) form they transfer in coded form; we need to decode for seeing an image. Many of challenges in deep space network to overcome. let’s divide controlling in two parts for better understanding:
To locate own exact location
Rocket contains GPS, Accelerometers, Gyroscopes, and too many sensors to know its own exact location from earth and distance from the target. The GPS sensor is connected through controllers. this sensor sent a radio signal to the satellite to know the exact location of the rocket. Rocket generally moved in three directions vertically, left, right.
To know where the target is
Rocket focus on target is a result of accurate calculation, timing. Time changes with different interplanetary space. timing calculation should be done according to gravitational acceleration. When the altitude increases velocity increases due to two reasons
- Mass decrease
- Gravity decrease
The rocket knows the location of the target with the help of radio waves and satellites. path decision of rocket is based on upper two factors.
Fuels and oxidizers
The propellant has some requirements for better efficiency of the rocket. there are some properties for propellant –
- The calorific value of propellant must be high and density should be high for low space requirement. negligible Corrosion characteristic. Ignition should be smooth. Release high pressure nearly 270-350kg/cm after burning.
- It can use a cryogenic or coolant purpose.
List of propellant used in rocket engine
The freezing point of this propellant is high and need to add some chemicals for decreasing its freezing point. This fuel is most explosive. UDNH is a derivative of hydrazine is also used as a propellant.
liquid hydrogen is grouped is a cryogenic propellant. the boiling point of liquid hydrogen is very low. It requires larger volume because they are in form of liquid and density of the liquid is low compared to other fuel. A chemical reaction is important in this propellant. this is grouped under liquid propellant
it is used as a liquid propellant with specified oxidizer, but the combustion temperature is low compared to others.
List of oxidizer used in rocket
The most common rocket oxidizer used in a rocket is liquid hydrogen. This oxidizer can be used with many rocket propellants. it is a cryogenic oxidizer, means it can be used for cooling purpose.
highly reactive fluid and leads to continuous combustion. It requires special volume container to handling. Nitrogen tetroxide, nitric acid, are also used as an oxidizer.
Before reading: Combustion chamber and Rocket engine nozzle
How rocket change orbit
For escaping earth orbit rocket needs to increase the semimajor axis, and it could be possible by increasing speed of the rocket. An orbit of any planet is possible because of the mass and gravity of a planet. Rocket assembly is specially designed to escape orbit. Geosynchronous orbit is the circular around the earth, and rocket follows these orbits. For changing orbit rocket need to reverse thrust for decrease velocity. All planets have an elliptical orbit and they move around the sun.
The Hohmann principle for orbit maneuvers is a fuel efficient method for orbit change. Hohmann transfer uses elliptical way to change orbit from lower orbit to higher orbit. For example, rocket take-off from north or south pole. The rocket moves in determined inclination, in this case, if we want to place rocket in equatorial orbit we need to decrease the velocity of the rocket.
The landing of rocket is can be divided into two part
- Landing on target surface
- Landing back in earth surface
The development of reusable rocket is essential for space travel. There are many methods of the landing of the rocket in target surface. the challenges in the landing of an object are entering in a gravitational area, this is the place where changes of the explosion are high. Recently new method used for dropping an object on the surface. the object is covered under a self-thrust generating device and with the help of wire string it will drop to the surface. Rocket use mid-air recovery used for landing back on earth. the aim of building a reusable rocket for making space travel more economical.