Image: Reaction Engines
How the Skylon fleet would operate
By Amjad P. Zaidi
A fleet of Skylon vehicles can
operate from a spaceport. A
Vehicle Loading Hall receives and
processes payloads which are
installed in the Skylon payload
bay. Skylon is then towed to the
spaceport’s
Refuelling
Apron.
Liquid Oxygen and Liquid Hydrogen
propellants are loaded through
connections in the wheel wells.
Skylon is towed to the runway for
pre-flight checks.
At the start of the take-off roll
the vehicle weighs 275 tonnes,
whilst maximum landing weight is
55 tonnes. At take-off the vehicle
carries approximately 66 tonnes of
liquid hydrogen and approximately
150 tonnes of liquid oxygen for the
ascent.
The SABRE engines are ignited
in air-breathing mode, burning
hydrogen fuel with air. Air must be
heavily cooled by heat exchangers
before being used by the hybrid
SABRE engine.
The SABRE engines have a dual
mode capability using the same
nozzles, pumps and hydrogen fuel
in-air breathing mode as in rocket
mode. In rocket mode the engine
operates as a closed cycle Lox/Lh2
high specific impulse rocket engine.
In air-breathing mode (from takeoff to Mach 5) the liquid oxygen
flow is replaced by atmospheric
air, increasing the installed specific
impulse 3-6 fold. The airflow is
drawn into the engine via a 2 shock
axisymmetric intake and is cooled
to cryogenic temperatures prior
to compression. The hydrogen fuel
acts as a heat sink for the closed
cycle helium loop before entering
the combustion chamber. The
intake and heat exchangers supply
the engines with air until the engine
switches to rocket mode.
Upon entering rocket mode
the air intakes close, the heat
exchangers stop and the engines
transfer to the on-board liquid
oxygen supply for rocket mode. This
transition takes place at Mach 5.5
and 25 kilometres altitude. Skylon
then pitches up and accelerates
climbing rapidly towards space.
Orbital manoeuvring engines in the
tail give the final boost into orbit.
In orbit, the payload doors are
opened. Skylon can deliver a
range of payloads to low Earth
orbit. The Skylon D1 configuration
has a 15 ton capacity to deliver a
variety of modern payloads from
space science satellites, Earth
observation satellites, and small
satellite conste llations to Low Earth
Orbit.
It can also launch Upper Stages
for
deploying
geostationary
satellites even further into space.
The Upper Stage propels a satellite
towards the correct orbit, separates
from the satellite and enables the
satellite to begin operations. The
Upper Stage continues on its orbit
to rendezvous with Skylon and be
reused on future missions.
Skylon can launch satellites and
so much more. Its large payload
bay makes it a flexible launch
system capable of transporting
people and supplies into space,
enabling space station resupply
missions, and transporting modules
for the construction of space
stations.
Even more is possible with space
hotels, servicing and fuel stations,
and large Orbit Transfer Vehicles,
performing
construction
and
logistics missions, using components
and supplies delivered by Skylon.
This even includes components
for the construction of vehicles for
missions to the Moon, Mars and
beyond.
On returning the Earth, the Orbital
Manoeuvring Engines fire, reducing
speed and allowing Skylon to reenter the atmosphere. Skylon
then glides to a runway landing,
completing its mission. Skylon is
then towed back to its hangar to
be made ready for its next mission
taking place within 48 hours.
Sources about the Skylon:
• www.reactionengines.co.uk
• Bloomberg: Skylon Spaceplane Discussion 31.07.13
• www.spacefuture.com
• www.bbc.co.uk/news/science-environment-23590080
• www.rocketeers.co.uk/taxonomy/term/42
• www.wired.co.uk/news/archive/2013-08/12/skylonalan-bond
• BBC Documentary: The Three Rocketeers
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