From Wikipedia, the free encyclopedia
A
Soyuz-FG
rocket launches from "
Gagarin's Start
" (Site 1/5),
Baikonur Cosmodrome
A
rocket
(from
Italian
:
rocchetto
,
lit.
'bobbin/spool') is a
vehicle
that uses
jet propulsion
to
accelerate
without using any surrounding
air
. A
rocket engine
produces thrust by
reaction
to exhaust expelled at high speed. Rocket engines work entirely from
propellant
carried within the vehicle; therefore a rocket can fly in the
vacuum
of space. Rockets work more efficiently in a vacuum and incur a loss of thrust due to the opposing pressure of the atmosphere.
Multistage rockets
are capable of attaining
escape velocity
from Earth and therefore can achieve unlimited maximum altitude. Compared with
airbreathing engines
, rockets are lightweight and powerful and capable of generating large
accelerations
. To control their flight, rockets rely on
momentum
,
airfoils
,
auxiliary reaction engines
,
gimballed thrust
,
momentum wheels
,
deflection of the exhaust stream
, propellant flow,
spin
, or
gravity
.
Rockets for military and recreational uses date back to at least 13th-century
China
. Significant scientific, interplanetary and industrial use did not occur until the 20th century, when rocketry was the enabling technology for the
Space Age
, including
setting foot on the Moon
. Rockets are now used for
fireworks
,
missiles
and other
weaponry
,
ejection seats
,
launch vehicles
for
artificial satellites
,
human spaceflight
, and
space exploration
.
Chemical rockets
are the most common type of high power rocket, typically creating a high speed exhaust by the
combustion
of
fuel
with an
oxidizer
. The stored propellant can be a simple pressurized gas or a single
liquid fuel
that disassociates in the presence of a catalyst (
monopropellant
), two liquids that spontaneously react on contact (
hypergolic propellants
), two liquids that must be ignited to react (like kerosene (RP1) and liquid oxygen, used in most
liquid-propellant rockets
), a solid combination of fuel with oxidizer (
solid fuel
), or solid fuel with liquid or gaseous oxidizer (
hybrid propellant system
). Chemical rockets store a large amount of energy in an easily released form, and can be very dangerous. However, careful design, testing, construction and use minimizes risks. (
Full article...
)