آر إس-25

RS-25
A rocket engine firing. A blue flame is projecting from a bell-shaped nozzle with several pipes wrapped around it. The top of the nozzle is attached to a complex collection of plumbing, with the whole assembly covered in steam and hanging from a ceiling-mounted attachment point. Various pieces of transient hardware are visible in the background.
RS-25 test firing
(the bright area at the bottom of the picture is a Mach diamond)
بلد الأصلالولايات المتحدة
أول طيران12 أبريل 1981 (STS-1)
الصانعRocketdyne, Pratt & Whitney Rocketdyne, Aerojet Rocketdyne
مركبة الإطلاق المقترنةمكوك الفضاء
نظام الإطلاق الفضائي
السابقHG-3
الوضعOut of service since STS-135, in testing for SLS
سائل
النسق
نسبة الفوهة69:1[1]
الأداء
الدفع (فراغ)512,300 رطلق (2,279 )[1]
الدفع (SL)418,000 رطلق (1,860 kن)[1]
نسبة الدفع إلى الوزن73.1[2]
ضغط التجويف2,994 psi (20.64 Mبا)[1]
دنو (فراغ)452.3 ثوان (4.436 كم/ث)[1]
دنو (SL)366 ثوان (3.59 كم/ث)[1]
الأبعاد
الطول168 بوصة (4.3 م)
القطر96 بوصة (2.4 م)
الوزن الجاف7,775 رطلs (3,527 kغ)
المراجع
المراجع[3][2]
ملاحظاتData is for RS-25D at 109% throttle.


The Aerojet Rocketdyne RS-25, otherwise known as the Space Shuttle main engine (SSME),[4] 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).

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 kن (418,000 رطلق) 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 (Isp) of 452 ثوان (4.43 كم/ث) in a vacuum, or 366 ثوان (3.59 كم/ث) at sea level, has a mass of approximately 3.5 طن متري (7,700 رطلs), 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 °م (−423 °ف) to 3300 °C (6000 °F).[1]

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

A diagram showing the components of an RS-25 engine. See adjacent text for details.
RS-25 schematic
A flowchart showing the flow of liquid hydrogen fuel through an RS-25 engine. See adjacent text for details.
Fuel flow
A flowchart showing the flow of liquid oxygen oxidizer through an RS-25 engine. See adjacent text for details.
Oxidizer flow
RS-25 propellant flow




Turbopumps

نظام المؤكسد

نظام الوقود

Powerhead

The SSME is a compact tangle of pipework attached to a much larger rocket nozzle.
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).[5]


Preburners

غرفة الاحتراق الرئيسية

Nozzle

Three bell-shaped rocket engine nozzles projecting from the aft structure of a Space Shuttle orbiter. The cluster is arranged triangularly, with one engine at the top and two below. Two smaller nozzles are visible to the left and right of the top engine, and the orbiter's tail fin projects upwards toward the top of the image. In the background is the night sky and items of purging equipment.
The nozzles of مكوك فضاء كلومبيا's three RS-25s following the landing of STS-93



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جهاز التحكم

A black, rectangular box, with cooling fins mounted to its outer surface. Various tubes and wires project from the side of the box facing the camera, with the other side mounted to a complex of silvery plumbing. The box is nestled in amongst other wires and pieces of hardware, and some warning stickers are attached to the casing.
A Block II RS-25D main engine controller



الصمامات الرئيسية

Gimbal

SSME gimbal test


نظام الهليوم

التاريخ

التطوير

RS-25 testing at Stennis Space Center




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برنامج مكوك الفضاء

Three bell-shaped rocket engine nozzles projecting from the aft structure of a Space Shuttle orbiter. The cluster is arranged triangularly, with one engine at the top and two below, with two smaller nozzles visible to the left and right of the top engine. The three larger engines are firing, with white-hot flames visible projecting from each nozzle. The Space Shuttle's left solid rocket booster (a white, cylindrical rocket) is visible in the background, with the two large, grey tail service masts visible to the left and right of the orbiter's aft structure.
مكوك فضاء أتلانتس's three RS-25D main engines at liftoff during STS-110
SSME startup and shutdown sequences



التحديثات

A chart showing the flight history of each RS-25 used during the Space Shuttle program, sorted by engine version.
Flight history of the Space Shuttle Main Engines


Engine throttle/output

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


حوادث

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


Constellation

Six rocket engines, consisting of a large bell-shaped nozzle with working parts mounted to the top, stored in a large warehouse with white walls decorated with flags. Each engine has several pieces of red protective equipment attached to it and is mounted on a yellow wheeled pallet-like structure.
The 6 RS-25Ds used during STS-134 and STS-135 in storage at Kennedy Space Center


نظام الإطلاق الفضائي

A diagram showing the configuration of a Space Launch System rocket consisting of an orange first stage with a cluster of RS-25s at its base and flanked by two solid rocket boosters. This stage is topped with a white second stage and several measurements are indicated. See adjacent text for details.
NASA's SLS reference configuration from February 2011



اختبارات المحرك

إكس إس-1

انظر أيضاً

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

Shuttle.svg
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.
  1. ^ أ ب ت ث ج ح خ Aerojet Rocketdyne, RS-25 Engine (accessed July 22, 2014)
  2. ^ أ ب Wade, Mark. "SSME". Encyclopedia Astronautica. Retrieved December 28, 2017.
  3. ^ "Space Shuttle Main Engine" (PDF). Pratt & Whitney Rocketdyne. 2005. Archived from the original (PDF) on February 8, 2012. Retrieved November 23, 2011.
  4. ^ "RS-25 Engine".
  5. ^ خطأ استشهاد: وسم <ref> غير صحيح؛ لا نص تم توفيره للمراجع المسماة Orientation

وصلات خارجية