RLV-LEX MISSION - SCI
& TECH
News: ISRO all set for third
reusable launch vehicle landing experiment
What's in the news?
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Taking its Reusable Launch Vehicle (RLV) programme
one more step closer to reality, the Indian Space Research Organisation (ISRO)
is all set to carry out the third and final RLV landing experiment (RLV LEX).
Key takeaways:
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RLV-LEX missions involve taking an unmanned winged prototype, christened
Pushpak, to a designated height and releasing it to land safely under varying conditions.
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In LEX-03, Pushpak will be carried to a height of
4.5 km and 500 metres to one side of the runway using an IAF Chinook helicopter
and released.
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In LEX-02, the second mission, the altitude was the
same but the lateral distance from the runway was 150 metres.
ISRO’s RLV TD project:
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ISRO aims to develop RLVs, or space
planes/shuttles, which can travel to low
earth orbits to deliver payloads and return
to earth for use again.
Objective:
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To develop
essential technologies for a fully reusable launch vehicle to enable
low-cost access to space.
Mission:
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The RLV-TD will be used to develop technologies
like hypersonic flight (HEX),
autonomous landing (LEX), return
flight experiment (REX), powered
cruise flight, and Scramjet Propulsion Experiment (SPEX).
Features:
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ISRO’s RLV-TD looks like an aircraft. It consists
of a fuselage, a nose cap, double delta wings, and twin vertical tails.
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The 2016
experiment involved sending a winged spacecraft on a rocket powered by a
conventional solid booster (HS9) engine used by ISRO into space. The spacecraft
traveled at a speed of Mach 5 (five times the speed of sound) when re-entering
the earth’s orbit and traveled a distance of 450 km before splashdown in the
Bay of Bengal.
Significance:
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With the costs acting as a major deterrent to space
exploration, a reusable launch vehicle is considered a low-cost, reliable, and on-demand mode of accessing space.
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Nearly 80 to 87 percent of the cost in a space
launch vehicle goes into the structure of the vehicle. The costs of propellants
are minimal in comparison.
○
By using RLVs, the cost of a launch can be reduced by nearly 80 percent of the present
cost.
Go back to basics:
First Experiment:
●
In the first flight, critical technologies such as autonomous navigation, guidance and
control, reusable thermal protection system, and re-entry mission management
have been successfully validated.
Second Experiment:
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In the second flight, autonomous landing under the exact conditions of a Space Re-entry
vehicle’s landing - high speed, unmanned, precise landing from the same return
path were tested.
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It also tested landing parameters such as ground
relative velocity, the sink rate of landing gears, and precise body rates, as
might be experienced by an orbital re-entry space vehicle in its return path,
were achieved.
Difference Between First
and Second Experiment:
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According to ISRO, the first test with RLV-TD
(HEX1) involved the vehicle landing on a hypothetical runway over the Bay of
Bengal while the LEX experiment conducted recently involved a precise landing on a runway.
Three More Experiments - Return flight experiment (REX), powered cruise flight, and Scramjet
Propulsion Experiment (SPEX) have to be
conducted.