A Cryogenic rocket stage is more efficient and provides more thrust for
every kilogram of propellant it burns compared to solid and
earth-storable liquid propellant rocket stages. Specific impulse (a
measure of the efficiency) achievable with cryogenic propellants
(liquid Hydrogen and liquid Oxygen) is much higher compared to earth
storable liquid and solid propellants, giving it a substantial payload
advantage.
However, cryogenic stage is technically a very complex system compared to solid or earth-storable liquid propellant stages due to its use of propellants at extremely low temperatures and the associated thermal and structural problems.
Oxygen liquifies at -183 deg C and Hydrogen at -253 deg C. The propellants, at these low temperatures are to be pumped using turbo pumps running at around 40,000 rpm. It also entails complex ground support systems like propellant storage and filling systems, cryo engine and stage test facilities, transportation and handling of cryo fluids and related safety aspects.
ISRO's Cryogenic Upper Stage Project (CUSP) envisaged the design and development of the indigenous Cryogenic Upper Stage to replace the stage procured from Russia and used in GSLV flights. The main engine and two smaller steering engines of CUS together develop a nominal thrust of 73.55 kN in vacuum. During the flight, CUS fires for a nominal duration of 720 seconds.
Liquid Oxygen (LOX) and Liquid Hydrogen (LH2) from the respective tanks are fed by individual booster pumps to the main turbopump to ensure a high flow rate of propellants into the combustion chamber. Thrust control and mixture ratio control are achieved by two independent regulators. Two gimbaled steering engines provide for control of the stage during its thrusting phase.
India is the 6th country in world to possess cryo engine after United States, Russia, and China, as well as France and Japan.
Sun Synchronous Orbit: A Sun-synchronous orbit (sometimes called a heliosynchronous orbit) is a geocentric orbit which combines altitude and inclination in such a way that an object on that orbit ascends or descends over any given Earth latitude at the same local mean solar time. The surface illumination angle will be nearly the same every time. This consistent lighting is a useful characteristic for satellites that image the Earth's surface in visible or infrared wavelengths (e.g. weather and spy satellites) and for other remote sensing satellites (e.g. those carrying ocean and atmospheric remote sensing instruments that require sunlight). For example, a satellite in sun-synchronous orbit might ascend across the equator twelve times a day each time at approximately 15:00 mean local time. This is achieved by having the osculating orbital plane precess (rotate) approximately one degree each day with respect to the celestial sphere, eastward, to keep pace with the Earth's movement around the Sun.
Geo Synchronous Orbit:
Also known as geostationary orbits, satellites in these
orbits circle the Earth at the same rate as the Earth spins. The Earth
actually takes 23 hours, 56 minutes, and 4.09 seconds to make one full
revolution. So based on Kepler's Laws of Planetary Motion, this would
put the satellite at approximately 35,790 km above the Earth. The
satellites are located near the equator since at this latitude, there is
a constant force of gravity from all directions. At other latitudes,
the bulge at the center of the Earth would pull on the satellite.
eosynchronous
orbits allow the satellite to observe almost a full hemisphere of the
Earth. These satellites are used to study large scale phenomenon such
as hurricanes, or cyclones. These orbits are also used for
communication satellites. The disadvantage of this type of orbit is
that since these satellites are very far away, they have poor
resolution. The other disadvantage is that these satellites have
trouble monitoring activities near the poles. See the picture below.
The more correct term would be near polar orbits. These
orbits have an inclination near 90 degrees. This allows the satellite
to see virtually every part of the Earth as the Earth rotates underneath
it. It takes approximately 90 minutes for the satellite to complete one
orbit. These satellites have many uses such as measuring ozone
concentrations in the stratosphere or measuring temperatures in the
atmosphere.
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However, cryogenic stage is technically a very complex system compared to solid or earth-storable liquid propellant stages due to its use of propellants at extremely low temperatures and the associated thermal and structural problems.
Oxygen liquifies at -183 deg C and Hydrogen at -253 deg C. The propellants, at these low temperatures are to be pumped using turbo pumps running at around 40,000 rpm. It also entails complex ground support systems like propellant storage and filling systems, cryo engine and stage test facilities, transportation and handling of cryo fluids and related safety aspects.
ISRO's Cryogenic Upper Stage Project (CUSP) envisaged the design and development of the indigenous Cryogenic Upper Stage to replace the stage procured from Russia and used in GSLV flights. The main engine and two smaller steering engines of CUS together develop a nominal thrust of 73.55 kN in vacuum. During the flight, CUS fires for a nominal duration of 720 seconds.
Liquid Oxygen (LOX) and Liquid Hydrogen (LH2) from the respective tanks are fed by individual booster pumps to the main turbopump to ensure a high flow rate of propellants into the combustion chamber. Thrust control and mixture ratio control are achieved by two independent regulators. Two gimbaled steering engines provide for control of the stage during its thrusting phase.
India is the 6th country in world to possess cryo engine after United States, Russia, and China, as well as France and Japan.
Sun Synchronous Orbit: A Sun-synchronous orbit (sometimes called a heliosynchronous orbit) is a geocentric orbit which combines altitude and inclination in such a way that an object on that orbit ascends or descends over any given Earth latitude at the same local mean solar time. The surface illumination angle will be nearly the same every time. This consistent lighting is a useful characteristic for satellites that image the Earth's surface in visible or infrared wavelengths (e.g. weather and spy satellites) and for other remote sensing satellites (e.g. those carrying ocean and atmospheric remote sensing instruments that require sunlight). For example, a satellite in sun-synchronous orbit might ascend across the equator twelve times a day each time at approximately 15:00 mean local time. This is achieved by having the osculating orbital plane precess (rotate) approximately one degree each day with respect to the celestial sphere, eastward, to keep pace with the Earth's movement around the Sun.
Geo Synchronous Orbit:
Geosynchronous Orbits
Polar Orbits
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