آر إس-25

The Aerojet Rocketdyne RS-25, otherwise known as the Space Shuttle main engine (SSME), is a liquid-fuel cryogenic rocket engine that was used on NASA's Space Shuttle. NASA is planning to continue using the RS-25 on the Space Shuttle's successor, the Space Launch System (SLS).

RS-25

RS-25 test firing (the bright area at the bottom of the picture is a Mach diamond)
بلد الأصل	الولايات المتحدة
أول طيران	12 أبريل 1981 (STS-1)
الصانع	Rocketdyne, Pratt & Whitney Rocketdyne, Aerojet Rocketdyne
مركبة الإطلاق المقترنة	مكوك الفضاء نظام الإطلاق الفضائي
السابق	HG-3
الوضع	Out of service since STS-135, in testing for SLS
سائل
النسق
نسبة الفوهة	69:1
الأداء
الدفع (فراغ)	512,300 lbf (2,279 kN)
الدفع (SL)	418,000 lbf (1,860 kN)
نسبة الدفع إلى الوزن	73.1
ضغط التجويف	2,994 psi (20.64 MPa)
دنو (فراغ)	452.3 seconds (4.436 km/s)
دنو (SL)	366 seconds (3.59 km/s)
الأبعاد
الطول	168 inches (4.3 m)
القطر	96 inches (2.4 m)
الوزن الجاف	7,775 pounds (3,527 kg)
المراجع
المراجع
ملاحظات	Data is for RS-25D at 109% throttle.

Designed and manufactured in the United States by Rocketdyne (later known as Pratt & Whitney Rocketdyne and Aerojet Rocketdyne), the RS-25 burns cryogenic liquid hydrogen and liquid oxygen propellants, with each engine producing 1,859 kN (418,000 lb_f) of thrust at liftoff. Although the RS-25 can trace its heritage back to the 1960s, concerted development of the engine began in the 1970s, with the first flight, STS-1, occurring on April 12, 1981. The RS-25 has undergone several upgrades over its operational history to improve the engine's reliability, safety, and maintenance load.

The engine produces a specific impulse (I_sp) of 452 seconds (4.43 km/s) in a vacuum, or 366 seconds (3.59 km/s) at sea level, has a mass of approximately 3.5 tonnes (7,700 pounds), and is capable of throttling between 67% and 109% of its rated power level in one-percent increments. The RS-25 operates at temperatures ranging from −253 °C (−423 °F) to 3300 °C (6000 °F).

The Space Shuttle used a cluster of three RS-25 engines mounted in the stern structure of the orbiter, with fuel being drawn from the external tank. The engines were used for propulsion during the entirety of the spacecraft's ascent, with additional thrust being provided by two solid rocket boosters and the orbiter's two AJ10 orbital maneuvering system engines. Following each flight, the RS-25 engines were removed from the orbiter, inspected, and refurbished before being reused on another mission.

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 المكونات

RS-25 schematic

Fuel flow

Oxidizer flow

RS-25 propellant flow

 Powerhead

The large silver pipe across the top carries fuel from the low-pressure fuel turbopump (not visible) to the high pressure fuel turbopump (HPFTP, silver drum at lower left). The top of the HPFTP is bolted to part of the hot gas manifold (black, with brown diagonal pipe) and above that is the fuel preburner (also black, with brown pipe entering at right).

 Nozzle

The nozzles of مكوك فضاء كلومبيا's three RS-25s following the landing of STS-93

 جهاز التحكم

A Block II RS-25D main engine controller

 Gimbal

SSME gimbal test

 التاريخ

 التطوير

RS-25 testing at Stennis Space Center

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 برنامج مكوك الفضاء

انظر أيضاً: قائمة مهام برنامج مكوك الفضاء

مكوك فضاء أتلانتس's three RS-25D main engines at liftoff during STS-110

SSME startup and shutdown sequences

 التحديثات

Flight history of the Space Shuttle Main Engines

 Engine throttle/output

	مستوى سمطح البحر	Vacuum
100% thrust	2,094.22272928 kN (470,799.99838 lbf)	2,120 kN (480,000 lbf)
104.5% thrust	1,750 kN (390,000 lbf)	2,170 kN (490,000 lbf)
109% thrust	1,860 kN (420,000 lbf)	2,280 kN (510,000 lbf)

 حوادث

This Shuttle control panel is set to select the abort to orbit (ATO) option, as used in the STS-51-F mission. After orbit was achieved, the mission continued normally and the orbiter returned to Earth with the crew.

Recovered power-head of one of Columbia's main engines. Columbia was lost on re-entry, from a suspected heat shield failure.

 Constellation

The 6 RS-25Ds used during STS-134 and STS-135 in storage at Kennedy Space Center

 نظام الإطلاق الفضائي

انظر أيضاً: نظام الإطلاق الفضائي

NASA's SLS reference configuration from February 2011

 إكس إس-1

انظر أيضاً: إكس إس-1 (مركبة فضاء)

 انظر أيضاً

• المكوك-سي

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 الهوامش

ڤيديو خارجي

STS-49 Flight Readiness Firing

Time-lapse video of STS-135 SSME installation

RS-25 Engine Test for SLS on 28 May 2015

RS-25 Engine controller system test on 27 July 2017

 المصادر

هذه الصورة من إنتاج ناسا و أخذت من صفحة ناسا (NASA) أو من منشوراتها. حقوق النشر لناسا تُؤكد أن منتوجاتها ليست محمية من طرف حقوق النشر، إلا إذا ذُكِر ذلك. للمزيد من المعلومات، المرجوا الاطلاع على صفحة ناسا لحماية حقوق النشر.

 وصلات خارجية

• Spherical panoramas of RS-25D in SSME Processing Facility prior to shipping to Stennis Space Center