This presentation briefly reviews the history of Reusable Launch Vehicle development and reuse techniques. The presentation considers a range of techniques for recovery and reuse of launch vehicles. Various different concepts of reusability have been discussed. The economics of reuse and the advantages of this technology is also presented.
2. WHAT IS REUSABLE LAUNCH VEHICLE ?
• A Reusable launch vehicle (RLV) refers to a vehicle
which can be used for several missions.
• A Reusable Launch Vehicle is the space analog of an
aircraft. Ideally it takes off vertically on the back of
an expendable rocket and then glides back down
like an aircraft. During landing phase, an RLV can
either land on a runway or perform a splashdown.
• The main advantage of an RLV is it can be used
multiple times, hopefully with low servicing costs.
The expendable rocket that is used for launching the
RLV can also be designed to be used multiple times.
A successful RLV would surely cut down mission
costs and make space travel more accessible.
3. HISTORY
The thought of Reusable launch vehicles started in
1950’s, but serious attempts at completely reusable
launch vehicles started in the 1990s. The most
prominent were the McDonnell-Douglas DC-X and the
Lockheed Martin X-33 VentureStar.
DC-X X-33 VentureStar
4. TODAY
• SpaceX is a recent player in the private launch market
succeeding in converting its Falcon 9 expandable launch
vehicle into a partially reusable vehicle by returning
the first stage for reuse.
• On 23 November 2015, Blue Origin New Shepard rocket
became the first proven Vertical Take-off Vertical Landing
(VTVL) rocket which can reach space 100.5 kilometers.
5. Working of an RLV
• Subsonic and supersonic Stage
• Hypersonic Stage
• Space Stage
• Re Entry Stage
- Upto about 100,000 feet or 30 km.
- Use a combination of conventional jet-engine and
ramjet engine.
- Plane is accelerated to a speed of mach 4 or mach 5.
- At an altitude of about 100,000 feet and at a velocity of
about mach 4.
- Combustion and ignition takes place in milliseconds.
- Scramjet engines takes RLV to mach 15.
- Rocket engines are fired as there isn’t enough oxygen
for scramjet engines.
- RLV is accelerated to mach 25.
- Rocket engine takes RLV to payload release site and
required operations are performed.
- RLV performs de-orbit operations to slow itself down.
- It drops to lower orbit and enters upper atmospheric
layers.
- RLV uses its aerodynamics to glide down once it reaches
dense air.
6. Design of an RLV
Body: The body has to withstand very high stresses. It
has to cope with the rapid change in temperatures which
changes from -250°C in shade to 250°C in direct sunlight.
Wings: Delta wings provides enough lift to fly to space
and also reduce the friction during re-entry.
Cockpit: Cockpit has double-paned glass windows which
can withstand the force of flight, pressure and vacuum.
Oxygen bottles are used to add breathable air. An
absorber system removes the exhaled carbon dioxide.
Electrical Power: The power required is taken from
lithium batteries which could be charged, if needed by
using solar energy.
8. Stages to orbit
• Single-stage-to-orbit (SSTO) reaches the space orbit
carrying small payloads of 9,000 to 20,000kg without
losing any hardware to LEO.
• Two-stage-to-orbit (TSTO or DSTO) are two
independent vehicles which interactions while
launching.
• Cross Feed has two or three similar stages are
stacked side by side, and burn in parallel. They
carry heavy payloads to outer space.
9. Vertical Landing
• Parachutes could be used to land vertically, either at sea,
or with the use of small landing rockets, on land
• Rockets could be used to softland the vehicle on the
ground from the subsonic speeds reached at low
altitude. This typically requires about 10% of the landing
weight of the vehicle to be propellant.
• Alternately, autogyro or helicopter rotor. This requires
perhaps 2-3% of the landing weight for the rotor.
10.
11. Retro-Propulsion/ Backward Propulsion
• Retro-propulsion means firing
your rocket engines against your
velocity vector in order to
decelerate.
• The vehicle fires its rockets
towards the surface to slow the
craft’s descent, after parachutes
had already brought it below
the speed of sound.
• It is very expensive in the sense
that the fuel required for
landing must be carried to
space, which erodes the
useable payload capacity of the
launch system.
12. Mid-Air Recovery (MAR)
• The reentering vehicle is slowed by means
of parachutes, and then a specially
equipped aircraft matches the vehicle's trajectory and
catches it in mid-air.
• This approach avoids high impact accelerations and/or
emersion in salt water.
• MAR can be up to (and beyond) a 10 ton payload. It
has been successfully demonstrated for 1000 lbs class
objects
13. Launch Assistance/Non Rocket Space
Launch
• Stratolaunch uses an aircraft to gain some initial
velocity and altitude; either by towing, carrying or
even simply refueling a vehicle at altitude.
• Rocket sled launch (ground based launch assist)
• Launch loop or Lofstrom loop
• Space Tether or Tether Propulsion
• Space Elevator
Stratolaunch
Rocket Sled Launch
Launch loop
Space Tether
Space Elevator
14. Preparing for Reuse
• The vehicle requires extensive inspection and
refurbishment.
• Each and every part of the launch vehicle needed to
be individually inspected. For example the orbiter’s
thermal protection tiles needed to be individually
inspected (and potentially replaced).
• Main engines needed to be removed to undergo
extensive inspection and overhaul.
• Parts contaminated with ocean salt water and had to
be cleaned, disassembled, and refurbished before
reuse.
16. Advantages of an RLV
• Cost is the first and foremost consideration, Reusable
Launch Vehicles reduce cost very much by avoiding
repeatedly making of new use and throw launch vehicles.
• International Space Station needs periodical replenishment
and may need other support missions from earth even at
short notice. RLVs become very useful in these
circumstances.
• India is getting and trying to get more commercial launches
of other nations' satellites. By using dependable RLV s the
frequency of missions can be increased and more number
of commercial payloads can be carried into space.
17. Reusable launch systems have the highest development
costs and technical risks, but the technology is within
current state of the art. Current efforts to economically
recover and reuse launch vehicle elements are more
promising than they have ever been. A reusable system
has extremely low direct operating costs. A future
reusable launch vehicle should be constructed within
low cost, use cryogenic engine for all stages.
Autonomous reusable launch vehicles are considered
to be low cost alternatives. Future RLV are to be
developed through an extensive flight demonstration.
Conclusion
18. References
Research Papers:
• Bhavana Y, Mani Shankar N and Prarthana BK (2013) “Reusable
Launch Vehicle: Evolution Redefined”. J Aeronaut Aerospace Eng: 2-2
• Mohamed M. Ragab, F. McNeil Cheatwood, Stephen J. Hughes and
Allen Lowry “Launch Vehicle Recovery and Reuse”. Acta Astronautica:
41-11
Thesis:
• Greg J. Gstattenbauer “Cost Comparison Of Expendable, Hybrid, And
Reusable Launch Vehicles”. Air Force Institute of Technology, Ohio
Websites:
• Wikipedia
• Quora
• YouTube
• ISRO (isro.gov.in/launchers/rlv-td)
• SpaceX (spacex.com/news/2013/03/31/reusability-key-making-
human-life-multi-planetary)
