At the 31st Space Symposium on April 13, 2015 , United Launch Alliance (ULA) announced that its Next Generation Launch System (NGLS) would be named “Vulcan”, after the Roman god of fire. The company also revealed plans for a step-by-step Vulcan development process that would keep some existing EELV elements in service for years.
During the first step, a new booster stage will replace the existing Atlas 5 Common Core Booster (CCB). The new 5 meter diameter booster will be powered, as previously announced, by two Blue Origin BE-4 LOX/LNG engines. It will lift existing Centaur stages and existing four or five meter diameter payload fairings. As many as four solid rocket boosters (SRBs) can be added to augment the four meter rocket, while up six SRBs can boost the five meter rocket. The solids will also be offered for competitive bidding, but are expected to be similar to the existing Aerojet Atlas 5 solids.
With six SRBs and a Centaur within a five meter fairing, Vulcan would lift more payload than Atlas 5-551, but less than Delta 4 Heavy.
During the second step, the Centaur second stage will be replaced by a heavier and more powerful stage named Advanced Cryogenic Evolved Stage (ACES). ACES will carry three times more LH2/LOX propellant than Centaur and will produce more thrust than Centaur. ACES will also feature an “Integrated Vehicle Fluids” system that will use existing propellant boil-off gases for thrusting, pressurization, and electricity generation, eliminating or reducing hydrazine and helium systems and batteries. Another competition will be held to determine which engine or engines will power ACES. Contenders include RL10, Blue Origin’s BE-3U, and an XCOR engine. With six SRBs and ACES, Vulcan will be able to outlift the existing Delta 4 Heavy.
A tri-core “Vulcan Heavy” topped by an ACES could conceivably lift an impressive 22.6 tonnes to geosynchronous transfer orbit – 1.6 times more than Delta 4 Heavy – but development of such a heavy-lifter is unlikely.
ULA will consider recovery of the BE-4 engines, using a heat shield, a parachute, and helicopter air recovery.
ULA’s existing Delta 4 Medium will be phased out beginning in 2018, as Vulcan with Centaur begins to fly. Delta 4 Heavy will be phased out later, likely when ACES begins to fly in 2023. When Delta 4 Heavy stops flying, one launch pad on each coast will be retired. Retiring Delta 4 will free up 5 meter tank tooling for Vulcan.
Also read: New Launchers – Esa Vega
ULA/Blue Origin to Develop Powerful New Engine (September 17, 2014)
BE-4 Model at Press Conference
On September 17, 2014, United Launch Alliance and Blue Origin, a privately held company owned by Amazon.com founder Jeff Bezos, announced that they were teaming to jointly fund development of Blue Origin’s new BE-4 rocket engine. The development effort would last four years, with full-scale testing in 2016 and first flight in 2019. The new engine would be available for use by both companies.
BE-4 will burn liquid oxygen and liquefied natural gas (LNG) in an oxygen rich staged combustion cycle to produce 550,000 pounds (249.5 tonnes) of sea level thrust. ULA boosters would use two BE-4s to produce 1,100,000 pounds (499 tonnes) of total thrust at sea level.
Blue Origin has been working on BE-4 development for three years, with component testing underway at the company’s test site near Van Horn, Texas and in facilities near Kent, Washington. Completed testing has included subscale oxygen-rich preburner development and staged combustion testing of the preburner and main injector assembly. Testing of the turbopumps and main valves is the next major step. A large new test facility was completed in May, 2014 in Texas to support full-scale engine testing.
BE-4 will likely operate at a specific impulse comparable to the Atlas 5 RD-180, but not as high as Delta 4’s RS-68. The engine could be heavier than RD-180, and the less dense propellant would force use of bigger, heavier tanks than those used by Atlas 5, but BE-4s higher thrust compared to RD-180 would help offset those factors.
ULA noted that BE-4 is not a direct replacement for RD-180, but that “two BE-4s are expected to provide the engine thrust for the next generation ULA vehicles”. The company said that the “next generation vehicles” would “maintain the key heritage components of ULA’s Atlas and Delta rockets”, including the strap-on solid boosters, and said that details would be announced at a later date.
Potential NGLS Appearance (Unofficial Estimates)
The phrase “Next Generation Launch System” (NGLS) has been linked with ULA’s BE-4 powered design. The company was expected to reveal details of NGLS during 2015.
NGLS is likely to be designed to use existing launch pads, upper stages, and payload fairings to the greatest extent possible. Since LNG is less dense than kerosene, one possibility is that ULA will use Delta 4 Common Booster Core 5.1 meter diameter tanks for the BE-4 powered first stage. This would allow the first stage to be the same height as the Atlas 5 Common Core Booster first stage, which is about 4.2 meters shorter than the Delta 4 CBC. Since two BE-4 engines would produce a bit more thrust than a single RD-180 engine at liftoff, the NGLS first stage would likely weigh an equivalant amount more than the Atlas 5 first stage.
At liftoff, the NGLS first stage thrust could be augmented in some vehicle variants by the same Aerojet solid rocket motors (SRBs) that power Atlas 5. At 1.55 x 17.7 meters and weighing more than 46 tonnes loaded, the composite case, single-segment motors produce 172 tonnes of thrust at liftoff. ULA may want to increase the number of SRBs beyond the maximum of five used by Atlas 5 to provide a variant capable of replacing Delta 4 Heavy. This NGLS Heavy would require a new, or upgraded, upper stage, but once developed would be able to perform EELV Heavy missions using a single-core vehicle.
For NGLS, ULA is likely to initially continue use of the Atlas 5 Centaur, the descendant of the world’s first liquid hydrogen/oxygen upper stage. Centaur uses stainless steel balloon tanks, with the lower LOX and upper LH2 tanks separated by a common elliptical bulkhead. The Atlas 5 Centaur is transitioning from its original restartable Pratt & Whitney RL10A-4-2 engine to an updated Aerojet Rocketdyne RL10C-1 engine. Both use a fixed carbon-carbon composite nozzle extension. RL10C-1 produces 10.383 tonnes of thrust at about 450 seconds ISP, compared to RL10A-4-2 thrust of 10.12 tonnes of thrust at 450.5 seconds ISP.
ULA will likely want to replace the RL10C-1 engines at some point in the future with a new, more efficient 15 tonne thrust class engine.
Thin-skinned Centaur cannot support the heavier 500-series payloads, so the existing Atlas 5 setup that uses a Contraves 5-meter diameter composite fairing to transfer payload weight to the first stage by enclosing Centaur will likely be used. This approach was originally used for the Centaur stages on Titan 3E and Titan 4. The fairing itself was derived from Ariane 5 designs.
ULA currently launches Atlas 5 from Cape Canaveral Space Launch Complex (SLC) 41 and Vandenberg AFB SLC 3 East. It also launches Delta 4 from Cape Canaveral SLC 37B and Vandenberg AFB SLC 6. At the Cape, Atlas V is assembled in a new 85.4 meter tall Vertical Integration Facility (VIF) and transported 550 meters on a mobile launch platform to the pad no more than 24 hours before liftoff. The Vandenberg pad uses a conventional mobile service tower, rather than a “clean pad”.
The company will want to consolidate these costly launch support facilities for NGLS. If a single-core NGLS can be designed to perform a range of missions from EELV Medium to EELV Heavy, it should be possible to retire Delta 4, allowing the company to abandon SLC 6 and SLC 37B. NGLS could then fly from updated SLC 41 and SLC 3 East. In this scenario, NGLS will also replace Atlas 5, allowing ULA to end use of Russian-made engines.
Vehicle Configurations (Estimated)
| LEO Payload (metric tons) (185 km x 28.5 deg)(1) | LEO Payload (metric tons) (407 km x 51.6 deg) | LEO Payload (metric tons) (200 km x 28.5 deg) (1) 90.0 deg) (2) | GTO Payload 1500 m/s to GEO* (metric tons)## | GTO Payload 1800 m/s to GEO (metric tons)## | GEO Payload (metric tons) | Configuration | LIftoff Height (meters) | Liftoff Mass (metric tons) | |
| Vulcan 401 (est) | 14.4 t | 13.4 t | 12.5 t (2) | – | 5.7 t | 2.7 t | Core + SEC/DEC + EPF | 58.3 m | 432 t |
| Vulcan 421 (est) | 17.3 t | 16.3 t | 15.3 t (2) | – | 6.9 t | 3.4 t | Core + 2SRB +SEC + EPF | 58.3 m | 527 t |
| Vulcan 441 (est) | 20.0 t | 18.9 t | 17.5 t (2) | – | 8.1 t | 4.0 t | Core + 4SRB +SEC + EPF | 58.3 m | 620 t |
| Vulcan 501 (est) | 13.7 t | 12.7 t | 11.8 t (2) | – | 5.5 t | 2.5 t | CCB + SEC/DEC + 5mSPLF | 62.2 m | 434 t |
| Vulcan 521 (est) | 16.5 t | 15.3 t | 14.4 t (2) | – | 6.7 t | 3.2 t | CCB + SEC/DEC + 3SRB + 5mSPLF | 62.2 m | 530 t |
| Vulcan 541 (est) | 19.0 t | 18.0 t | 17.1 (1) | – | 7.7 t | 3.8 t | CCB + SEC/DEC + 4SRB + 5mSPLF | 62.2 m | 623 t |
| Vulcan 56x/Aces (est) | 36.0 t | 33.0 t | 31.0 (t) | – | 15.06 t | 7.26 t | Core + 6SRB + ACES + 5mSPLF | 63 m | 781 t |
| Vulcan Heavy/Aces (est) | – | – | – | – | 22.68 t | – | 3Core + ACES + 5mSPLF | 63 m | 1,280 t |
# Using Dual Engine Centaur
## Using Single Engine Centaur
* GEO: Geosynchronous Earth Orbit
Shaded Models to be Phased Out as RL-10C-1 Enters Service
Vehicle Components (NGLS Building Blocks)
| SRBs (Aerojet) | NGLS First Stage | Centaur (Lockheed Martin) Single (SEC) Engine | ACES | 400 Interstage | 500 Interstage | |
| Diameter (m) | 1.55 m | 5.1 m (est) | 3.05 m | 5.1 m | 3.85/3.05 m | 3.83 m |
| Length (m) | 17.7 m | 32.46 m (est) | 12.68 m | – | 4.78 m | 4.31 m |
| Usable Propellant Mass (tonnes) | 42.63 t | ~360 t | 20.8 t | ~63.5 t | ||
| Total Mass (tonnes) | 46.26 t | ~394 t | 22.83 t | ~69.8 t | 0.8 t | 1.57 t |
| Engine | AJ-62 | BE-4 | RL-10C-1 | – | ||
| Engine Manufacturer | Aerojet | Blue Origin | Aerojet Rocketdyne | – | ||
| Fuel | HTPB | LNG | LH2 | LH2 | ||
| Oxidizer | HTPB | LOX | LOX | LOX | ||
| Thrust (sea level, tonnes) | 172.2 t | 499 t | – | |||
| Thrust (vac (avg) tonnes) | 126.98 t | ~540 t (est) | 10.383 t | ~44 t | ||
| ISP (sea level, sec) | 245 s | ~310 s | – | |||
| ISP (vac sec) | 275 s | ~335 s | ~450 s | ~460 | ||
| Burn Time (sec) | 90 s | ~240 s | ~835 s (SEC) | – | ||
| No. Engines | 1 | 2 | 1 | 1-4 |
Vehicle Components, Cont’d
| 400 Large Fairing | 400 Extended Fairing | 5 m Short Fairing | 5 m Long Fairing | ||
| Diameter (meters) | 4.2 m | 4.2 m | 5.4 m | 5.4 m | |
| Length (meters) | 12.2 m | 13.1 m | 20.7 m | 23.4 m | |
| Mass (tons) | 2.09 t | 2.26 t | 4.09 t | 4.65 t |
======================================================================================
======================================================================================
Date Vehicle ID Payload Mass Site* Orbit Orbit
kg (kmxkmxdeg) Type**
----------------------------------------------------------------------------------------
NN/NN/NN NGLs NNNNN NNNNN NNNN CC41 NNNxNNNNNxNN.NN AAA
----------------------------------------------------------------------------------------
*Site Code:
CC = Cape Canaveral, FL, USA
CC37B = Space Launch Complex 37B: Delta 4
CC41 = Space Launch Complex 41: Atlas 5
VA = Vandenberg AFB, CA, USA
VA3E = Space Launch Complex 3E: Atlas 5
VA6 = Space Launch Complex 6: Delta 4
