|Space Launch Report The Road to Ares V|
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The Road to Ares V - a Short History
Ares V, NASA's proposed heavy-lift lunar exploration cargo launch vehicle, nearly realized the long-considered "Shuttle-derived" concept.
Studies of heavy-lift Shuttle-derived launch vehicles actually predated Space Shuttle. Boeing performed one of the first "Shuttle-derived" launch vehicle studies for NASA in 1977, four years before the first Space Shuttle flight. The company evaluated a side-mount design with an expendable cargo shroud and recoverable propulsion module, carrying three or four Space Shuttle Main Engines (SSMEs), mounted to the side of a standard External Tank. Twin four-segment Solid Rocket Boosters (SRBs) straddled the tank. The design was expected to lift 91 to 102 tonnes to low Earth orbit (LEO). Like most early concepts of this type, it was designed to co-exist with Shuttle, requiring few launch facility modifications.
NASA contemplated such heavy-lift cargo-only flights as a way to handle what, at the time, appeared to be a rapidly expanding Shuttle payload manifest for NASA, for the Department of Defense, and for commercial satellite operators.
Martin Marietta reexamined the Shuttle-derived concept during 1980-83 for NASA's Marshall Space Flight Center (MSFC). With one Martin design, up to 68 tonnes of payload could be carried within a large side-mount "Payload Module" that would mimic many features of the Shuttle payload bay, and would therefore reduce payload compared to the earlier Boeing design. A recoverable "Propulsion/Avionics Module" mounted below the Payload Module would house three SSMEs. The company also considered something new: "Inline" designs that carried payloads atop the tank in a traditional payload fairing. An "Inline II" design powered by four to six SSMEs, carried two-to-three-apiece in each of two side-mounted propulsion modules, would have lifted 109 to 136 tonnes to LEO.
During the 1980s, Boeing
also proposed what may have been the first true in-line Shuttle-derived designs, with
engines below the core and payload above. One "Shuttle Derived Cargo Launch
Vehicle" design described in 1982 used a single expendable SSME placed below a
shortened ET-based core, straddled by a pair of shortened three-segment SRBs - a design
similar to an Ares I alternative proposed 24 years later that was nicknamed
"Stumpy". When fitted with a low-thrust hypergolic boost (circularization)
stage, it would have been able to haul 29.5 tonnes to LEO. With four-segment SRBs,
it would have lifted 39.55 tonnes. A more powerful vehicle powered by standard SRBs
and two SSMEs mounted in an aft recovery module would have orbited 68 tonnes.
After the January 1986 loss of Challenger, numerous Shuttle-derived concepts appeared, or reappeared. Boeing Aerospace dusted off its in-line concepts when the company became involved with Hughes Aircraft's 1986 U.S. Air Force Medium Launch Vehicle (MLV) competition submission. Hughes was also trying to find a way to launch the many commercial communications satellites it was building that had been grounded by the Challenger failure.
Named "Jarvis" after Hughes employee Gregory Jarvis who was lost with Challenger, the initial design used ET-diameter tanks, but no other Shuttle elements. It would have been powered by a pair of F-1 Saturn V first stage engines and a single J-1 second stage engine. A smaller hypergolic trim stage would have been used to place up to six GPS satellites, or up to 38.6 tonnes, into orbit during a single launch.
By the end of 1986, Boeing had shifted the design toward its earlier in-line Shuttle-derived plans. Using four-segment SRBs, a core stage with a single SSME would have orbited 36 tonnes. A two-SSME core would have launched nearly 64 tonnes. Three SSMEs would have lifted nearly 84 tonnes. Two SSMEs in a recovery module would have orbited 59 tonnes. With a Centaur G-Prime upper stage, Jarvis would have been able to boost 7.7 tonnes to geosynchronous orbit, roughly equivalent to 15.5 tonnes to geosynchronous transfer orbit (GTO). Although Jarvis was never developed, the Boeing/Hughes relationship eventually spawned an active commercial launch system named Sea Launch.
The 1987 launch of the side-mount heavy lift Energia launch vehicle by the Soviet Union, coupled with potential heavy payload needs of the U.S. Strategic Defense Initiative, provided even more impetus to heavy lift launch vehicle development. The Pentagon, with some NASA involvement, initiated the Advanced Launch System (ALS) program in 1987, an effort to define a "cleen sheet" heavy lift launch vehicle architecture. Although some interim ALS designs included Space Shuttle components like SSMEs, most of the long-term ALS designs veered from Shuttle derived hardware or launch facilities, which were deemed too costly. The ALS program quickly turned into a technology incubating effort, but it did support early work on a new, lower-cost "Space Transportation Main Engine" (STME).
Shuttle-C, a side-mount NASA
design studied from 1987 to 1990, nearly entered development before Congress cancelled
it. With three non-recoverable SSMEs, Shuttle-C would have lifted up to 77 tonnes to
LEO. A larger Shuttle-Z design, powered by four SSMEs, would have orbited 136
tonnes. Shuttle-C would have helped build the Space Station, among other things.
1990s In-Line Designs
In 1991, NASA Ames and Martin Marietta proposed an in-line design, named "Ares", for launching "Mars-Direct" missions. This "Mars-Direct Ares", with payload on top, would have been powered off the pad by four SSMEs in a side-mounted recoverable module and two Advanced Solid Rocket Motors (ASRMs). A liquid hydrogen upper stage with a new highly efficient 113 tonne thrust engine allowed the vehicle to lift 121 tonnes to LEO (130 tonnes if two engines were used). A core-only variant with no upper stage would have orbited 75 tonnes. If two standard four-segment SRBs were used in place of the proposed ASRMs, LEO payload for the two-stage rocket fell to 106 tonnes.
An important in-line design, with engines below the core and payload above, was the joint NASA/USAF National Launch System (NLS) of the early 1990s. NLS would have used the new lower-cost STME from the ALS program. Each STME would have produced 250 tonnes of liftoff thrust (365 sec ISP) and 295 tonnes of thrust in vacuum (428.5 sec ISP). STME would go on to serve as the model for today's RS-68 engine, making NLS an early ancestor of today's Ares V. Four STMEs would have been mounted directly below the ET-diameter core, which would have been boosted by twin four segment SRBs. A "medium-lift" variant, named "NLS-2", would have used a 1.5 stage version of the core, with a total of six STMEs and no SRBs, to orbit 23 tonnes. The heavy-lift rocket, named "NLS-1", would have lifted up to 61.2 tonnes to LEO. Perceived high projected development costs and the end of the Cold War led Congress to terminate NLS funding in October 1992.
NLS-1 served as the starting
point for repeated lunar and Mars exploration launch vehicle studies during the 1990s,
iniitally in response to President George H. W. Bush's 1989 "Space Exploration
NASA's 1992 First Lunar Outpost (FLO) study, headed, interestingly enough, by NASA's Office of Exploration head Dr. Michael D. Griffin, who became NASA Administrator in 2005, considered a heavy lifter that replaced the NLS-1 SRBs with two to four kerosene strap on boosters powered by Saturn V F-1A type engines. This rocket, informally dubbed "Comet" according to some reports, added a dual-SSME-powered Trans-Lunar Injection (TLI) stage on top of the NLS-1 core to boost up to 95 tonnes to TLI. Numerous designs of the FLO "Comet" type were evaluated during NASA's extensive Advanced Transportation Systems Studies of the mid-1990s. The four-booster model would have weighed 5,610 tonnes at liftoff, rising on 7,531 tonnes (16.6 million pounds) of earth-pummeling liftoff thrust. Such massive launch vehicles were considered because, Griffin said in 1992, his group had determined that a lunar launch vehicle would have to lift 1.5 times as much payload as a Saturn V.
In 1996, NASA's Marshall Space Flight Center studied
in-line Shuttle-derived heavy lifters, leading to the "Magnum" launch vehicle
designs. One of several "Magnum" designs, an in-line arrangement with
standard four-segment SRBs, used four SSMEs housed in recoverable
Propulsion/Avionics modules and a final insertion "kick
stage". It would have lifted 80 tonnes to LEO. Another variant, that
replaced the SSMEs with two STME-type engines beneath the core, would have orbited 55
tonnes. More powerful versions would have required liquid, rather than solid,
strap-on boosters. Magnum appeared in late 1990s presentations given by Michael
Griffin when he was an Executive VP at Orbital Sciences.
Post-Columbia In-Line Designs
ATK Heavy Lifter, 2004
The Shuttle-derived idea faded in the face of budget realities during the later 1990s, not reappearing until after the 2003 loss of orbiter Columbia and crew and the early 2004 "Vision for Space Exploration" plan announced by President Bush, which was a long-term plan for NASA to retire Shuttle and to send astronauts to the Moon and eventually Mars. Heavy-lift proposals were quickly dusted off, especially when it became apparent that NASA was interested in a capsule based approach. Orbital Sciences re-introduced an 80 tonne to LEO "Magnum" type design boosted by four expendable SSMEs. ATK proposed use of four or five expendable SSMEs on an ET-based core augmented by new five-segment SRBs. An upper stage could be powered by an SSME or by a pair of J-2S engines. LEO payloads of 100 tonnes to more than 135 tonnes were suggested.
At the same time, ATK proposed a separate "single-stick" Crew Launch Vehicle that would use a single SRB topped by a new upper stage. This approach was soon embraced by incoming NASA Administrator Michael Griffin, who in 2005 assigned a committee to perform the landmark Exploration Systems Architecture Studies (ESAS), which examined a wide variety of launch systems for exploring the Moon and Mars. The final recommendation looked much like ATK's 2004 proposal, which in turn was heavily based on "Magnum", "Comet", "Mars Direct Ares", National Launch System and others.
Ares V Defined, and Redefined
In 2006, NASA modified the heavy-lift "Cargo Launch Vehicle" design from the ESAS recommended version, expanding the core stage to 10 meters in diameter, replacing the core stage SSMEs with RS-68 engines, and replacing the specified pair of J-2S second stage engines with a single new higher-performance "J-2X" engine. Only the second stage retained the Shuttle External Tank diameter. The new rocket, able to boost nearly 130 tonnes to LEO, was named "Ares V" in late 2006. This Ares V essentially served as the baseline until 2008. Subsequent designs expanded the second stage to 10 meters diameter, added a sixth RS-68 engine, and contemplated use of a 5.5 segment booster.
The final Ares V was barely, if at all, "Shuttle-derived" since it no longer used Space Shuttle four-segment SRBs, External Tanks, or Space Shuttle Main Engines. It would, however, have been built, tested, and launched using modified Space Shuttle facilities.
The program was cancelled along with
Project Constellation on February 1, 2010. The cancellation, coupled with the
planned end of Shuttle, ended, for the time being at least, consideration of
"Shuttle-derived" launch vehicles.
The Role, Rationale, and Economics of a Shuttle Derived Cargo Vehicle, Frank Williams and Robert Tewell, Martin Marietta Aerospace, 1983..
Advanced Transportation Systems Studies, Technical Area 2, Heavy Lift Launch Vehicle Development Contract, NAS8-39208, Final Report, Lockheed Martin Missiles and Space for the Launch Systems Concepts Office of the George C. Marshall Space Flight Center, July 1995.
Heavy Lift Launch for Lunar Exploration, Michael D. Griffin, University of Wisconsin Lecture, 1997.
Extending Human Presence into the Solar System, An Independent Study for the Planetary Society on Strategy for the Proposed U.S. Space Exploration Policy, July 2004.
Service Life Extension Program Summit 2, Strategy Panel, Presentation by Doug Cooke, Chair, February 17, 2004.
Exploration Transportation System, Presentation by Mike Kahn of ATK at the 2004 Space Congress, April 2004.
Shuttle Derived Launch Vehicles - A Solution for Space Access, James A. Furfaro and Dennis G. Johnson, ATK Thiokol Inc., 2005.
Shuttle Derived In-Line Heavy Lift Vehicle, Terry Greenwood, MSFC, 2005.
NASA's Exploration Systems Architecture Study (ESAS), Final Report, NASA-TM-2005-214062, November 2005.
Upper Stage Request for Information, NASA's Exploration Launch Office, March 20, 2006.
Ares Project Status, Presentation by Steve Cook, Director Exploration Launch, NASA, Second AIAA Space Exploration Conference, December 2006.