more at
http://scitech.quickfound.net/astro/o...The
second J-2X rocket engine to be built is tested. Three J-2X engines
will be used to power the Block II Upper Stage (Earth Departure Stage)
of the Space Launch System. This advanced configuration is not expected
to fly until 2030 or later in the very slow SLS development schedule.
"J-2X
engine No. 10002 is tested June 13 on the A-1 Test Stand at NASA's
Stennis Space Center in south Mississippi. The 60-second test signals
the start of a series of firings to collect critical data on engine
performance. By the time the J-2X tests conclude later this summer, the
engine will have been fired at full power and for the total time it
would operate during an actual flight, while being gimbaled in the same
way it must move during flight. (NASA/SSC)"
Public domain film from NASA.
http://creativecommons.org/licenses/b...http://en.wikipedia.org/wiki/J-2XThe
J-2X is a liquid-fuel cryogenic rocket engine planned for use on NASA's
Space Launch System. Built in the United States of America by
Rocketdyne, the J-2X will burn cryogenic liquid hydrogen & liquid
oxygen propellants, with each engine producing 1,307 kN (294,000 lbf) of
thrust in vacuum at a specific impulse (Isp) of 448 seconds. The engine
will have a mass of approximately 5,450 pounds (2,470 kg),
significantly heavier than its predecessors.
The J-2X was
originally intended to be based on the J-2 used on the S-II and S-IVB
stages of the Saturn rockets used during the Apollo program, but as
required thrust for the Ares I increased due to weight problems it
became a clean sheet design. It entered development in 2007 as part of
the now-cancelled Constellation program. Originally planned for use on
the upper stages of the Ares I and Ares V rockets, the J-2X is now
intended for use in the 2030s and beyond on the Earth Departure Stage of
the Block II Space Launch System, the successor to the Constellation
program. The engine is intended to be more efficient and simpler to
build than its J-2 ancestor, and cost less than the RS-25 Space Shuttle
Main Engine. Differences in the new engine include the removal of
beryllium, a centrifugal turbo pump versus the axial turbo pump of the
J-2, different chamber and nozzle expansion ratios, a channel-walled
combustion chamber versus the tube-welded chamber of the J-2, a redesign
of all the electronics, supersonic injection, and the use of
21st-century joining techniques...
Testing
On 16 July 2007
NASA officially announced the award to Pratt & Whitney Rocketdyne
(PWR) of a $1.2 billion dollar contract "for design, development,
testing and evaluation of the J-2X engine", and began construction of a
new test stand for altitude testing of J-2X engines at Stennis Space
Center on 23 August 2007...
Starting in 2011, the full J-2X engine, derived from heritage and new designs, has undergone hot-fire tests.
- June 2011: The first hot-fire test.
- November 2011: A test-firing lasting 499.97 seconds.
- June 2012: A test-firing lasting 1,150 seconds, during which the J-2X was throttled up and down.
- July 2012: A test-firing for 1,350 seconds (22½ minutes)
- December 2012: Final test-firing [of the first engine built]
http://en.wikipedia.org/wiki/Space_La...The Space Launch System, or SLS, is a United States Space Shuttle-derived heavy launch vehicle...
The
SLS launch vehicle... initial Block I version, without an upper stage,
is to lift a payload of 70 metric tons to orbit. The final Block II
version with an integrated upper Earth Departure Stage is to, depending
on the configuration, have a payload lift capability of 130 metric tons
to low earth orbit, 12 metric tons above that of Saturn V, which would
make the SLS the most capable heavy lift vehicle ever built...
...Upper stage
The SLS will make use of several upper stages in its various configurations:
- Block 0 -- No upper stage.
-
Block I -- A Delta Cryogenic Second Stage (DCSS), referred to as the
Interim Cryogenic Propulsion Stage (ICPS). This 70-metric ton
configuration currently will only fly two missions: Exploration Mission 1
(EM-1) in 2017 and Exploration Mission 2 (EM-2) in 2021...
-
Block IA -- A large Cryogenic Propulsion Stage, specifically developed
for SLS and powered by liquid hydrogen fuel and liquid oxygen oxidizer.
This 105-metric ton rocket will first launch as SLS-3, nominally in
2023, and be followed by SLS-4 in 2025. Currently there are four
configurations of this vehicle under analysis by NASA, of which only two
will be produced.
- Block IB - CPS consisting of four RL10A-4-2 engines with a 8.4 m fairing and 105 mt to LEO.
-
Block II -- A fully-fledged Earth Departure Stage to be powered by
three J-2X engines. This 130-metric ton rocket evolution will not debut
until the 2030s. As with the Block IA there are also four corresponding
configurations of this vehicle under analysis by NASA.
