India’s Reusable Launch Vehicle-Technology Demonstrator (RLV-TD)

On May 23, 2016 ISRO successfully flight tested India’s first winged body aerospace vehicle operating in hypersonic flight regime. In this experimental mission, the HS9 solid rocket booster carrying RLV-TD lifted off from the First Launch Pad at SatishDhawan Space Centre, Sriharikota at 07:00hr IST. After a successful flight of 91.1second, HS9 burn out occurred, following which both HS9 and RLV-TD mounted on its top coasted to a height of about 56 km.

At that height, RLV-TD separated from HS9 booster and further ascended to a height of about 65km. From that peak altitude of 65 km, RLV-TD began its descent followed by atmospheric re-entry at around Mach 5 (five times the speed of sound).

The vehicle’s Navigation, Guidance and Control system accurately steered the vehicle during this phase for safe descent. After successfully surviving a high temperatures of re-entry with the help of its Thermal Protection System (TPS), RLV-TD successfully glided down to the defined landing spot over Bay of Bengal, at a distance of about 450km from Sriharikota, thereby fulfilling its mission objectives.

The vehicle was successfully tracked during its flight from ground stations at Sriharikota and a shipborne terminal. Total flight duration from launch to landing of this mission of the delta winged RLV-TD, lasted for about 770seconds.

In this flight, critical technologies such as autonomous navigation, guidance & control, reusable thermal protection system and re-entry mission management have been successfully validated.

ISRO acknowledge the support of Indian coast guard and National Institute of Ocean technology (NIOT) for the mid sea wind measurement and shipborne telemetry respectively in this mission.

GSLV D6
GSLV-D6 is the ninth flight of India's Geosynchronous Satellite Launch Vehicle (GSLV). It is also the fifth developmental flight of GSLV. This is the third time the indigenously developed Cryogenic Upper Stage (CUS) is being carried on-board during a GSLV flight.

GSLV-D6 flight is significant since it intends to continue the testing of CUS. GSLV is designed to inject 2 ton class of communication satellites into Geosynchronous Transfer Orbit (GTO). GSLV-D6 will be launched from the Second Launch Pad at SatishDhawan Space Centre SHAR (SDSC SHAR), Sriharikota.

GSLV-D6 will launch 2117 kg GSAT-6, an advanced communication satellite, into a GTO. GSAT-6 will provide S-band communication services in the country. After reaching GTO, GSAT-6 will use its own propulsion system to reach its final geostationary orbital home and will be stationed 0 at 83 East longitude.

GSLV-D6 vehicle is configured with all its three stages including the CUS similar to the ones successfully flown during the previous GSLV-D5 mission in January 2014. GSLV-D5 successfully placed GSAT-14 satellite carried on-board in the intended GTO very accurately.

The metallic payload fairing of GSLV-D6 has a diameter of 3.4 m. The overall length of GSLV-D6 is 49.1 m with a lift-off mass of 416 t.

The Cryogenic Upper Stage (CUS) being flown in GSLV-D6 is designated as CUS-06. 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.

The 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 challenges. 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.
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.

S-band telemetry and C-band transponders enable GSLV-D6 performance monitoring, tracking, range safety/flight safety and Preliminary Orbit Determination (POD).

MULTI - APPLICATION SOLAR TELESCOPE (MAST)
Multi Application Solar Telescope (MAST), a telescope for the detailed study of the Solar activity including its magnetic field, has recently been operationalised at the Udaipur Solar Observatory (USO) of Physical Research Laboratory (PRL), an autonomous unit of the Department of Space. MAST is an off-axis Gregorian-Coude telescope with a 50 cm aperture.

PRL is a premier research institute engaged in basic research in the areas of Astronomy and Astrophysics, Solar Physics, Planetary Science and Exploration, Space and Atmospheric Sciences, Geosciences and Theoretical Physics. Apart from the main campus at Ahmedabad, there are two other campuses at Mt. Abu and Udaipur, hosting the Infrared Telescope and a Multi-Application-Solar Telescope (MAST), respectively.

The planetary exploration (PLANEX) programme and the astronomy group are housed in the fourth campus at Thaltej, close to Ahmedabad.

The USO is situated on an island in the middle of the Lake Fatehsagar of Udaipur, Rajasthan, India. The sky conditions at Udaipur are quite favourable for solar observations. The large water body surrounding the telescopes decreases the amount of heating of the surface layers.

This decreases the turbulence in the air mass and thereby improves the image quality and seeing. The main objective of obtaining the high spatial and temporal resolution observations of solar photospheric and chromospheric activity is to understand the various dynamic phenomena occurring on the surface of the Sun.

The recently operationalised Multi Application Solar Telescope’s dome is a collapsible dome made of tensile fabric. Built by Mechanical and Optical Systems (AMOS) of Belgium, MAST was tested by USO for onsite acceptance. Test results accumulated over a year was examined by a committee of experts and telescope was made operationalized on June 16, 2015.

The back-end instruments of MAST, developed in-house at USO, include an adaptive optics system and a narrow band imaging polarimeter using a tandem Fabry-Perot etalon pair and LCVR polarimetric module. Another instrument, viz., a spectropolarimeter, has been developed at ISRO Satellite Centre and will be soon deployed at MAST.

MAST will be used to measure vector magnetic fields of active regions at different heights of the solar atmosphere. It will also be used to study seismic effects of solar flares. Some test images taken during the trial runs of MAST are shown in Figures, which include images taken with H-alpha and G-band filters.

FLOATING TEST RANGE FOR MISSILE DEFENCE SYSTEM
India is building a unique floating testing range — a huge ship — to overcome the limitations imposed by the land mass for carrying out missile tests of varying ranges for the two-tier ballistic missile defence (BMD) system to protect important cities.

The system seeks to engage and destroy incoming enemy missiles at different altitudes in the endo- and exo-atmospheres.

The first phase of the programme envisages development of interceptors to annihilate incoming missiles with a range of 2,000 km, while the second phase aims to build such weapons to destroy missiles with a longer range.

The system will waylay a ballistic missile and destroy it in mid-air.India has so far conducted 10 interceptor missile tests, eight of them successful. Most of the trials were conducted in the endo-atmosphere, and a few in the exo-atmosphere.

The first phase of the system is expected to be deployed after some more interceptor trials in deployable configuration. Currently the missile testing range on Wheeler Island posed certain limitations as people needed to be evacuated from the villages every time a trial took place. More important, the range of the missile had to be confined to less than 300 km. Also, different trajectories could not be tested.

To overcome these problems, scientists at the Defence Research and Development Organisation (DRDO) designed the floating testing range — a huge ship with a designated displacement equivalent to 10,000 tonnes.

The state-of-the-art range would have many facilities such as a launch-pad, a launch control centre and a mission control centre.The construction of the range, which has just started, might take at least three to four years for the ship to be ready to conduct the first trial.

“It will pave the way for conducting trials for different trajectories, varying altitudes and also for higher ranges. We can go up to 1,000-1,500 km without any problem. Currently, we conduct simulation tests for longer ranges. Once, this FTR is ready we will be able to carry out live tests.

KARWAR NAVAL BASE – The Largest To The East of Suez Canal.
INS Vajrakosh, a naval station near Karwar in Karnataka together with INS Kadamba, 20 km, away, is now the world's largest naval base east of the Suez Canal. Spread out over 1000 acres, the new naval base would be the home base for a bulk of the Indian Navy's strength on the western coast.

Indian Naval Station Vajrakosh - which loosely translates to 'Thunder Chest' - was constructed as the second phase of Project Seabird, which was initiated by the Centre in 1985. INS Kadamba had been commissioned earlier. INS Vajrakosh alone is spread out over 600 acres.

At the new naval base, The Indian Navy will be positioning two aircraft carriers - INS Vikramaditya and the indigenously built INS Vikrant - over 20 submarines in underground pens and 47 warships. Besides this, it will also have a Naval air station that will base the Boeing P-8i, an advanced maritime surveillance aircraft that is known as 'Poseidon'. The facility will also feature a helicopter base.

By:Balalatha Mallavarapu