You cannot use scramjet beyond 100kms you need oxidizer any how. Hence semicryogenic because you are using only LOX and Kerosene. Not LOX and LH.
The semi-cryogenic Project envisages the design and development of a 2000 kN semi-cryogenic engine for a future heavy-lift Unified Launch Vehicle (ULV) and Reusable Launch Vehicle (RLV). The semi-cryogenic engine uses a combination of Liquid Oxygen (LOX) and ISROSENE (propellant-grade kerosene), which are eco-friendly and cost-effective propellants.
http://isro.gov.in/sites/default/files/AnnualReports/2014/STS.html[/QUOTE]
i found this.on the page..
Air Breathing (AB) propulsion along with Reusable Launch Vehicle technology is the key for low cost access to Space. Unlike conventional rockets, Air Breathing Propulsion system makes use of atmospheric oxygen for combustion thus resulting in substantial improvement in payload fraction and reduction in overall cost.
ISRO has taken up a systematic R&D programme for demonstrating stable supersonic combustion through a series of ground tests on the Air-Breathing Propulsion Technology. The flight demonstration of this technology is planned with Advanced Technology Vehicle (ATV).
Towards Scramjet flight testing, mission studies have been carried out and feasibility established. Qualification and flight model of the Scramjet Engine Avionics Module with High Frequency Data Acquisition Units and its sub-systems were realised. Test and evaluation of these packages for flight were also successfully carried out.
Functional tests of the ignition system of scramjet with different mixture ratios of Gaseous Hydrogen – Gaseous Oxygen were carried out. High pressure gaseous hydrogen flow control module and a module for operating the start valves of Fuel Feed System for scramjet engine flight testing were realised.
The scramjet engine frame assembly for flight and the flow duct segments made out of super alloy Inconel-718 have been realised. Qualification test to demonstrate sliding capability of scramjet engine and vehicle interface was successfully carried out. The Scramjet Characterisation flight is targeted in 2014.
THEY ARE DEVELOPING SCRAMJET ENGINE TOO. SO SCRAMJET TO GET TO THE EDGE OF ATMOSPHERE AND SEMI CRYOGENIC FROM THERE TO SPACE..
WHY ELSE ISRO WILL DEVELOP SCRAMJET THEN