Saturday, February 9, 2019

Polar Satellite Launch Vehicle (PSLV) of ISRO

Polar Satellite Launch Vehicle or PSLV is the first Indian launch vehicle to be equipped with liquid stages. It's a 4stage, 44m high, 2.8m wide launching vehicle with 320 tons of lift-off mass. It carries 41.5 tonnes of liquid propellant – Unsymmetrical Dimethylhydrazine (UDMH) as fuel and Dinitrogen Tetroxide (N2O4) as an oxidizer for its indigenously made Vikas engine.
Vikas-Engine testing
PSLV  is the third generation launch vehicle of India and one of the most versatile launch vehicle across the globe. After its first successful launch in October 1994, PSLV emerged as the reliable and versatile workhorse launch vehicle of India with 39 consecutively successful missions by June 2017. During this period the vehicle has launched 48 Indian satellites and 209 satellites for customers from abroad.
The main speciality of this vehicle is versatility. It's the same rocket by which ISRO  launches its Chandrayaan (Lunar explore mission)  & Mars Orbiter Mission(MOM) & also broke the world record of deploying the maximum satellite in orbit in one launch. It broke the earlier record of launching 37 satellites of  Russia by successfully carried and deployed a record 104 satellites in Sun-Synchronous Orbits (SSO). It can carry up to  3,800 kg in Low Earth Orbit (LEO), 1,750 kg in  Sun-Synchronous Orbits (SSO), 1,425 kg in Sub-Geostationary Transfer Orbit (Sub-GTO) and 1,200 kg in Geostationary Transfer Orbit (GTO).

The vehicle has four stages using solid and liquid propulsion systems alternately. For this complex but efficient design, the rocket achieves such unique versatility. And that's why ISRO can launch satellite much cheaper in comparison to others.
Assembling the Second stage with the first stage & solid rocket motors

PSLV uses 6 solid rocket strap-on motors to augment the thrust provided by the first stage in its PSLV-G and PSLV-XL variants. It carries Hydroxyl-Terminated Polybutadiene-Bound (HTPB) as the propellant and generates 719 kilonewtons of thrust.
Stage one of the rocket is Solid rocket motor, carries 138 tonnes of HTPB propellant and develops a maximum thrust of about 4,800 kilonewtons. The first stage flight is provided by the Secondary Injection Thrust Vector Control System (SITVC).
Second stage with Vikash-Engine

The second stage employs the earth storable liquid rocket engine (Vikas engine) and carries 41.5 tonnes of liquid propellant which generates a maximum thrust of 800 kilonewtons.

After the atmospheric phase of the launch, the third stage of PSLV is a solid rocket motor that provides the upper stages with the high thrust. It also uses HTPB and generates 240 kilonewtons of thrust.

The fourth stage is the uppermost stage of PSLV, comprising of two Earth storable PS4 liquid engines. Each engine generating 7.6 kilonewtons of thrust and carrying  2,500 kg of Mono Methyl Hydrazine + Mixed Oxides of Nitrogen (MMH + MON) propellant in the PSLV and PSLV-XL and 2,100 kg in the PSLV-CA.

Due to its unmatched reliability, PSLV has also been used to launch various satellites into Geosynchronous and Geostationary orbits. It can take up to 1,750 kg of payload to Sun-Synchronous Polar Orbits (SSPO) of 600 km altitude.

And that's how it can outperform any space vehicle by its versatility and low launching cost. It's truly "the Workhorse of ISRO".

Thursday, September 20, 2018

ISRO- New success: NovaSAR, S1-4 & PSLV- C42

Sep16, 2018. PSLV-C42 successfully launches two foreign satellite from Satish Dhawan Space Centre (SDSC). The Polar Satellite Launch Vehicle (PSLV) was programmed to put NovaSAR & S1-4 in orbit, that is 583 km above the surface.
NovaSAR has the ability to take pictures of the surface of the Earth in every kind of weather, day or night. The spacecraft will assume a number of roles like forest mapping, land use & ice cover monitoring, flood & disaster monitoring but its designers specifically want to see if it can help monitor suspicious shipping activity.
S1-4 is a high-resolution Optical Earth Observation Satellite, used for surveying resources, environment monitoring, urban management and for the disaster monitoring. This spacecraft will discern objects on the ground as small as 87cm across.
Both S1-4 & NovaSAR were manufactured by Surrey Satellite Technology Limited of Guildford.

UK engineers have long had expertise in space radar but their technology has previously always gone on broader missions, such as those for the European Space Agency. NovaSAR, which has the distinctive shape of a cheese grater, is uniquely British. However, Its radar instrument was developed for SSTL by Airbus in Portsmouth. The mission incorporates low-cost, miniaturised components and will aim to demonstrate a more affordable approach to radar imaging. It will operate in a number of modes for applications that include the detection of oil spills, flood and forestry monitoring, disaster response, and crop assessment. But perhaps its most interesting role will be in maritime observation.


Low-cost was the first priority from the start of this project & ISRO did a great job at launching these 889 kgs payload (Together NovaSAR & S1-4) successfully with the help of its versatile PSLV-C42.

Launch at a glance