Jul 25, 2009 · The RS-68A engine, an upgraded version of the current RS-68 liquid hydrogen-liquid oxygen engine used on Delta IV, will allow the Delta IV Heavy vehicle to boost heavier payloads into orbit. Currently, the RS-68 engine can deliver more than 660,000 pounds of sea level thrust and the upgraded RS-68A will increase this to more than 700,000 pounds ...

Apr 11, 2022 · The RS-68A differs from the RS-68 in having slightly greater thrust, producing 705,000 lbf (3,140 kN) thrust at sea level and 800,000 lbf (3,560 kN) thrust in a vacuum. It was first flown on June 29, 2012, and all Delta IV launches following the launch of Delta flight 371 on March 25, 2015 have used the RS-68A as the first stage engine.

Aug 9, 2009 · The press release says specifically the RS-68A will be used on the Delta IV Heavy, but I presume they mean all Delta IV's, not just the heavy? Does anyone know what the expected lift capability will be with the upgraded engines?

Oct 4, 2012 · Have you looked at how many RS-68A engines it would take to get an SLS Block 1 core off the ground, i.e. to have a thrust-to-weight ratio greater than 1 at T-0? Or do you mean a core like SLS Block 1, only smaller, [EDIT: or larger], or only partially filled with propellant?

Feb 10, 2010 · Pratt & Whitney Rocketdyne will hot-fire test the first RS-68A certification engine a minimum of 12 times through February and follow that with a similar series of hot-fire tests on its second certification engine in March and April. Engine design certification review and acceptance of flight readiness are currently planned for July 2010.

Jul 7, 2014 · Could RS-68A with it's ablative nozzle have been clustered under a wide diameter core to make an all liquid HLV? Obviously with SRB's they couldn't survive. On D4H they can survive two other RS-68's that are 5m away, but that's only on two sides. Was a 10m HLV core with something like 8 RS-68A around it's perimeter, ever a possiblity?

Jun 2, 2012 · The remaining Delta IV Medium and Medium+ configurations are also expected to incorporate the RS-68A upgrade, with availability sometime after implementation on the Heavy configuration. My assumption based on that statement is the RS-68A will be used on all future DIV-H flights, and at some point in the future on non-heavy variants.

Jun 17, 2012 · The RS-68A was certified to three power levels -- minimum power level, full power level, and enhanced power level -- to meet flight performance objectives, improve engine acceptance yields, and preserve the ability to use the RS-68A as a drop-in replacement for the RS-68, the current Delta IV first-stage engine.

Aug 23, 2014 · Since regenerative RS-68 will likely never be funded, here's a concept: An 8.4 meter Corestage with 5 or 6x RS-25E and surrounded with 16x Aerojet solid boosters from the Atlas V. Or 16x GEM-60 solids; some of them airlit? Upper stage: 2x J2X or 5x MB-60. Extensive use of composites and aluminum/lithium. 'Rocket Lego'? Maybe. But I'd love to know the performance... 120 metric tons to L.E.O?

Oct 13, 2012 · It is an effect of ascent aerodynamics you understand, where hot plume gases flow upstream at the base end of a supersonic body, similar to plume-induced flow separation, which can go significantly up the length of the side of a vehicle. It has to do with the shape of the aft end mostly, and is a function of aerodynamic blockage, Mach number, angle of attack and hot gas source.Slick SLS Block ...