manu/mldr-zoomed-100char-total-queries-documents

chunk_id stringlengths 3 9	chunk stringlengths 1 100
9828_274	upon the number of Earth orbits required to attain the lunar window for translunar trajectory.
9828_275	History Development
9828_276	Inspiration for the J-2 dates back to various NASA studies conducted in the late 1950s, of
9828_277	LH2-fuelled engines producing thrust of up to following the success of the RL-10 used on the
9828_278	Atlas-Centaur's Centaur upper stage. As ever-heavier launch vehicles entered consideration, NASA
9828_279	began to look at engines producing thrusts of up to , with development being officially authorized
9828_280	following the 1959 report of the Saturn Vehicle Evaluation Committee. A source evaluation board was
9828_281	formed to nominate a contractor from five bidding companies, and approval was given on 1 June 1960
9828_282	for Rocketdyne to begin development of a "high-energy rocket engine, fuelled by LOX and hydrogen,
9828_283	to be known as the J-2". The final contract, awarded in September 1960, was the first to explicitly
9828_284	require the design "insure maximum safety for crewed flight."
9828_285	Rocketdyne launched the development of the J-2 with an analytical computer model that simulated
9828_286	engine operations and aided in establishing design configurations. The model was supported by a
9828_287	full-sized mockup which was used throughout development to judge the positioning of the engine's
9828_288	components. The first experimental component, the engine's injector, was produced within two months
9828_289	of the contract being awarded, and testing of the engine's components began at Rocketdyne's Santa
9828_290	Susana Field Laboratory in November 1960. Other test facilities, including a vacuum chamber and
9828_291	full-size engine test stand, were used during the development, with the engine's turbopumps
9828_292	entering testing in November 1961, the ignition system in early 1962, and the first prototype
9828_293	engine running a complete 250-second test run in October 1962. In addition to flight hardware, five
9828_294	engine simulators were also used during the development process, assisting in the design of the
9828_295	engine's electrical and mechanical systems. Contracts were signed between NASA and Rocketdyne in
9828_296	the summer of 1962, requiring 55 J-2 engines to be produced to support the final designs for the
9828_297	Saturn rockets, which required five engines for each S-II second stage of the Saturn V and one
9828_298	engine for each S-IVB Saturn IB and Saturn V third stage.
9828_299	The J-2 entered production in May 1963, with concurrent testing programs continuing to run at
9828_300	Rocketdyne and at MSFC during the manufacturing run. The first production engine, delivered in
9828_301	April 1964, went for static tests on the S-IVB test stage at the Douglas test facility near
9828_302	Sacramento, California and underwent its first full-duration (410 seconds) static test in December
9828_303	1964. Testing continued until January 1966, with one engine in particular igniting successfully in
9828_304	30 successive firings, including five tests at full duration of 470 seconds each. The total firing
9828_305	time of 3774 seconds represented a level of accumulated operational time almost eight times greater
9828_306	than the flight requirements. As successful single-engine tests moved toward their completion,
9828_307	integration tests of the propulsion system with the S-IVB accelerated with the availability of more
9828_308	production engines. The first operational flight, AS-201, was scheduled in early 1966 for the
9828_309	Saturn IB using the S-IB first stage and the S-IVB as the second stage.
9828_310	The first all-up test of a complete S-IVB, including its single J-2, in July 1965 was inconclusive
9828_311	when a component malfunction in one of the pneumatic consoles prematurely ended the test after a
9828_312	successful propellant loading and automatic countdown. Confidence in the design was regained in
9828_313	August, however, when the same stage, S-IVB-201, performed flawlessly on a full-duration firing of
9828_314	452 seconds, which was the first engine test sequence to be controlled entirely by computers. The
9828_315	J-2 was cleared for flight and, on 26 February 1966, AS-201 went through a flawless launch.
9828_316	In July 1966, NASA confirmed J-2 production contracts through 1968, by which time Rocketdyne agreed
9828_317	to finish deliveries of 155 J-2 engines, with each engine undergoing a flight qualification firing
9828_318	at the Santa Susana Field Laboratory before delivery to NASA. Reliability and development testing
9828_319	continued on the engine, with two uprated versions being used by NASA in the later flights of the
9828_320	Apollo program.
9828_321	Upgrades
9828_322	J-2S
9828_323	An experimental program to improve the performance of the J-2 started in 1964 as the J-2X (not to
9828_324	be confused with a later variant by the same name). The main change to the original J-2 design was
9828_325	a change from the gas generator cycle to a tap-off cycle that supplied hot gas from a tap on the
9828_326	combustion chamber instead of a separate burner. In addition to removing parts from the engine, it
9828_327	also reduced the difficulty of starting up the engine and properly timing various combustors.
9828_328	Additional changes included a throttling system for wider mission flexibility, which also required
9828_329	a variable mixture system to properly mix the fuel and oxygen for a variety of different operating
9828_330	pressures. It also included a new "Idle Mode" that produced little thrust for on-orbit maneuvering
9828_331	or to settle the fuel tanks on-orbit prior to a burn.
9828_332	During the experimental program, Rocketdyne also produced a small run of six pre-production models
9828_333	for testing, the J-2S. These were test fired many times between 1965 and 1972, for a total of
9828_334	30,858 seconds burn time. In 1972 it became clear no follow-on orders for Saturn boosters were
9828_335	coming, and the program shut down. NASA did consider using the J-2S on a number of different
9828_336	missions, including powering the Space Shuttle in a number of early designs as well as on the Comet
9828_337	HLLV.
9828_338	J-2T
9828_339	While work on the J-2S continued, NASA also funded a design effort to use the J-2S turbomachinery
9828_340	and plumbing to a toroidal combustion chamber with a new aerospike nozzle. This would improve
9828_341	performance even further. Two versions were built, the J-2T-200k that provided thrust, allowing it
9828_342	to be "dropped in" to the existing S-II and S-IVB stages, and the J-2T-250k of .
9828_343	Like the J-2S, work on the J-2T had progressed to a lengthy series of ground-based test runs, but
9828_344	further development ended in the post-Apollo draw-down.
9828_345	J-2X
9828_346	What became a different engine with a similar name, called the J-2X, was chosen in 2007 for the
9828_347	Project Constellation crewed lunar landing program. A single J-2X engine, generating of thrust,
9828_348	was to be used to power the Earth Departure Stage (EDS).
9828_349	NASA began construction of a new test stand for altitude testing of J-2X engines at Stennis Space
9828_350	Center (SSC) on 23 August 2007. Between December 2007 and May 2008, nine tests of heritage J-2
9828_351	engine components were conducted at SSC in preparation for the design of the J-2X engine.
9828_352	The new J-2X is designed to be more efficient and simpler to build than its Apollo J-2 predecessor,
9828_353	and cost less than the Space Shuttle Main Engine (SSME). Design differences include the removal of
9828_354	beryllium, modern electronics, a centrifugal turbo pump versus the axial turbo pump of the J-2, a
9828_355	different chamber and nozzle expansion ratios, a channel-walled combustion chamber versus the
9828_356	tube-welded chamber of the J-2, a redesign of all the electronics, supersonic injection and the use
9828_357	of 21st-century joining techniques.
9828_358	On July 16, 2007 NASA officially announced the award to Pratt & Whitney Rocketdyne, Inc. of a $1.2
9828_359	billion contract "for design, development, testing and evaluation of the J-2X engine" intended to
9828_360	power the upper stages of the Ares I and Ares V launch vehicles. On Sept. 8, 2008 Pratt & Whitney
9828_361	Rocketdyne announced successful testing of the initial J-2X gas generator design. The completion of
9828_362	a second round of successful gas generator tests was announced on September 21, 2010.
9828_363	Project Constellation was cancelled by President Barack Obama on October 11, 2010, but development
9828_364	of the J-2X has continued for its potential as the second stage engine for the new, heavy-lift
9828_365	Space Launch System. The first hot-fire test of the J-2X was scheduled for late June, 2011.
9828_366	On November 9, 2011 NASA conducted a successful firing of the J-2X engine of 499.97 seconds in
9828_367	duration.
9828_368	On February 27, 2013 NASA continued testing of the J-2X engine of 550 seconds in duration at NASA's
9828_369	Stennis Space Center.
9828_370	Specifications See also Comparison of orbital rocket engines References
9828_371	Rocket engines using hydrogen propellant Rocketdyne engines North American Aviation
9828_372	Apollo program hardware Rocket engines using the gas-generator cycle
9828_373	Rocket engines of the United States

9828_274

upon the number of Earth orbits required to attain the lunar window for translunar trajectory.

9828_275

History Development

9828_276

Inspiration for the J-2 dates back to various NASA studies conducted in the late 1950s, of

9828_277

LH2-fuelled engines producing thrust of up to following the success of the RL-10 used on the

9828_278

Atlas-Centaur's Centaur upper stage. As ever-heavier launch vehicles entered consideration, NASA

9828_279

began to look at engines producing thrusts of up to , with development being officially authorized

9828_280

following the 1959 report of the Saturn Vehicle Evaluation Committee. A source evaluation board was

9828_281

formed to nominate a contractor from five bidding companies, and approval was given on 1 June 1960

9828_282

for Rocketdyne to begin development of a "high-energy rocket engine, fuelled by LOX and hydrogen,

9828_283

to be known as the J-2". The final contract, awarded in September 1960, was the first to explicitly

9828_284

require the design "insure maximum safety for crewed flight."

9828_285

Rocketdyne launched the development of the J-2 with an analytical computer model that simulated

9828_286

engine operations and aided in establishing design configurations. The model was supported by a

9828_287

full-sized mockup which was used throughout development to judge the positioning of the engine's

9828_288

components. The first experimental component, the engine's injector, was produced within two months

9828_289

of the contract being awarded, and testing of the engine's components began at Rocketdyne's Santa

9828_290

Susana Field Laboratory in November 1960. Other test facilities, including a vacuum chamber and

9828_291

full-size engine test stand, were used during the development, with the engine's turbopumps

9828_292

entering testing in November 1961, the ignition system in early 1962, and the first prototype

9828_293

engine running a complete 250-second test run in October 1962. In addition to flight hardware, five

9828_294

engine simulators were also used during the development process, assisting in the design of the

9828_295

engine's electrical and mechanical systems. Contracts were signed between NASA and Rocketdyne in

9828_296

the summer of 1962, requiring 55 J-2 engines to be produced to support the final designs for the

9828_297

Saturn rockets, which required five engines for each S-II second stage of the Saturn V and one

9828_298

engine for each S-IVB Saturn IB and Saturn V third stage.

9828_299

The J-2 entered production in May 1963, with concurrent testing programs continuing to run at

9828_300

Rocketdyne and at MSFC during the manufacturing run. The first production engine, delivered in

9828_301

April 1964, went for static tests on the S-IVB test stage at the Douglas test facility near

9828_302

Sacramento, California and underwent its first full-duration (410 seconds) static test in December

9828_303

1964. Testing continued until January 1966, with one engine in particular igniting successfully in

9828_304

30 successive firings, including five tests at full duration of 470 seconds each. The total firing

9828_305

time of 3774 seconds represented a level of accumulated operational time almost eight times greater

9828_306

than the flight requirements. As successful single-engine tests moved toward their completion,

9828_307

integration tests of the propulsion system with the S-IVB accelerated with the availability of more

9828_308

production engines. The first operational flight, AS-201, was scheduled in early 1966 for the

9828_309

Saturn IB using the S-IB first stage and the S-IVB as the second stage.

9828_310

The first all-up test of a complete S-IVB, including its single J-2, in July 1965 was inconclusive

9828_311

when a component malfunction in one of the pneumatic consoles prematurely ended the test after a

9828_312

successful propellant loading and automatic countdown. Confidence in the design was regained in

9828_313

August, however, when the same stage, S-IVB-201, performed flawlessly on a full-duration firing of

9828_314

452 seconds, which was the first engine test sequence to be controlled entirely by computers. The

9828_315

J-2 was cleared for flight and, on 26 February 1966, AS-201 went through a flawless launch.

9828_316

In July 1966, NASA confirmed J-2 production contracts through 1968, by which time Rocketdyne agreed

9828_317

to finish deliveries of 155 J-2 engines, with each engine undergoing a flight qualification firing

9828_318

at the Santa Susana Field Laboratory before delivery to NASA. Reliability and development testing

9828_319

continued on the engine, with two uprated versions being used by NASA in the later flights of the

9828_320

Apollo program.

9828_321

Upgrades

9828_322

J-2S

9828_323

An experimental program to improve the performance of the J-2 started in 1964 as the J-2X (not to

9828_324

be confused with a later variant by the same name). The main change to the original J-2 design was

9828_325

a change from the gas generator cycle to a tap-off cycle that supplied hot gas from a tap on the

9828_326

combustion chamber instead of a separate burner. In addition to removing parts from the engine, it

9828_327

also reduced the difficulty of starting up the engine and properly timing various combustors.

9828_328

Additional changes included a throttling system for wider mission flexibility, which also required

9828_329

a variable mixture system to properly mix the fuel and oxygen for a variety of different operating

9828_330

pressures. It also included a new "Idle Mode" that produced little thrust for on-orbit maneuvering

9828_331

or to settle the fuel tanks on-orbit prior to a burn.

9828_332

During the experimental program, Rocketdyne also produced a small run of six pre-production models

9828_333

for testing, the J-2S. These were test fired many times between 1965 and 1972, for a total of

9828_334

30,858 seconds burn time. In 1972 it became clear no follow-on orders for Saturn boosters were

9828_335

coming, and the program shut down. NASA did consider using the J-2S on a number of different

9828_336

missions, including powering the Space Shuttle in a number of early designs as well as on the Comet

9828_337

HLLV.

9828_338

J-2T

9828_339

While work on the J-2S continued, NASA also funded a design effort to use the J-2S turbomachinery

9828_340

and plumbing to a toroidal combustion chamber with a new aerospike nozzle. This would improve

9828_341

performance even further. Two versions were built, the J-2T-200k that provided thrust, allowing it

9828_342

to be "dropped in" to the existing S-II and S-IVB stages, and the J-2T-250k of .

9828_343

Like the J-2S, work on the J-2T had progressed to a lengthy series of ground-based test runs, but

9828_344

further development ended in the post-Apollo draw-down.

9828_345

J-2X

9828_346

What became a different engine with a similar name, called the J-2X, was chosen in 2007 for the

9828_347

Project Constellation crewed lunar landing program. A single J-2X engine, generating of thrust,

9828_348

was to be used to power the Earth Departure Stage (EDS).

9828_349

NASA began construction of a new test stand for altitude testing of J-2X engines at Stennis Space

9828_350

Center (SSC) on 23 August 2007. Between December 2007 and May 2008, nine tests of heritage J-2

9828_351

engine components were conducted at SSC in preparation for the design of the J-2X engine.

9828_352

The new J-2X is designed to be more efficient and simpler to build than its Apollo J-2 predecessor,

9828_353

and cost less than the Space Shuttle Main Engine (SSME). Design differences include the removal of

9828_354

beryllium, modern electronics, a centrifugal turbo pump versus the axial turbo pump of the J-2, a

9828_355

different chamber and nozzle expansion ratios, a channel-walled combustion chamber versus the

9828_356

tube-welded chamber of the J-2, a redesign of all the electronics, supersonic injection and the use

9828_357

of 21st-century joining techniques.

9828_358

On July 16, 2007 NASA officially announced the award to Pratt & Whitney Rocketdyne, Inc. of a $1.2

9828_359

billion contract "for design, development, testing and evaluation of the J-2X engine" intended to

9828_360

power the upper stages of the Ares I and Ares V launch vehicles. On Sept. 8, 2008 Pratt & Whitney

9828_361

Rocketdyne announced successful testing of the initial J-2X gas generator design. The completion of

9828_362

a second round of successful gas generator tests was announced on September 21, 2010.

9828_363

Project Constellation was cancelled by President Barack Obama on October 11, 2010, but development

9828_364

of the J-2X has continued for its potential as the second stage engine for the new, heavy-lift

9828_365

Space Launch System. The first hot-fire test of the J-2X was scheduled for late June, 2011.

9828_366

On November 9, 2011 NASA conducted a successful firing of the J-2X engine of 499.97 seconds in

9828_367

duration.

9828_368

On February 27, 2013 NASA continued testing of the J-2X engine of 550 seconds in duration at NASA's

9828_369

Stennis Space Center.

9828_370

Specifications See also Comparison of orbital rocket engines References

9828_371

Rocket engines using hydrogen propellant Rocketdyne engines North American Aviation

9828_372

Apollo program hardware Rocket engines using the gas-generator cycle

9828_373

Rocket engines of the United States