DIRECT is a proposal for a set of Shuttle Derived Launch Vehicles. Developed independently from NASA, DIRECT proposes launch vehicles different from those NASA is developing in its Project Constellation. Like Project Constellation, however, DIRECT would enable the missions to the Moon, Mars and beyond that were outlined in the U.S. government's Vision for Space Exploration. The name "DIRECT" is intended to emphasize the use of components with a more direct heritage to the existing Space Shuttle design. For other uses, see Direct. ... In cargo transport, the payload is the valuable contents of the vehicle. ... A low Earth orbit (LEO) is an orbit in which objects such as satellites are below intermediate circular orbit (ICO) and far below geostationary orbit, but typically around 350 - 1400 km above the Earths surface. ... Launch Complex 39 is a large site and a collection of facilities at the John F. Kennedy Space Center on Merritt Island in Florida, USA, originally built for the Apollo program, and later modified to support Space Shuttle operations. ... Merritt Island and Kennedy Space Center (shown in white). ... Orion spacecraft in lunar orbit Orion spacecraft with docked LSAM lunar lander Orion spacecraft approaching the ISS Orion during a landing on Earth The Orion Spacecraft (formerly known as the Crew Exploration Vehicle or CEV) is a proposed series of American manned and unmanned spacecraft, intended to replace the Space... The Ares V Earth Departure Stage (EDS) is the high-energy cryogenic upper stage of NASAs proposed new Ares V launch vehicle. ... The LSAM launches its ascent stage to return the astronauts to Lunar Orbit. ... The Space Shuttle Solid Rocket Booster (SRB) is the rocket that provides 83% of liftoff thrust for the Space Shuttle. ... The Space Shuttle Columbia is initially launched with the help of solid-fuel boosters A solid rocket or a solid fuel rocket is a rocket with a motor that uses solid propellants (fuel/oxidizer). ... For other uses, see Newton (disambiguation). ... A pound-force (abbreviations: lbf or lbf) is a unit of force. ... Specific impulse (usually abbreviated Isp) is a way to describe the efficiency of rocket and jet engines. ... The Space Shuttle External Tank (ET) on its way to the Vehicle Assembly Building. ... The RS-68 (Rocket System 68) is the largest existing liquid hydrogen / liquid oxygen engine, producing a thrust of 650,000 lbf (2. ... Thrust is a reaction force described quantitatively by Newtons Second and Third Laws. ... For other uses, see Newton (disambiguation). ... Specific impulse (usually abbreviated Isp) is a way to describe the efficiency of rocket and jet engines. ... This article does not cite any references or sources. ... This article does not adequately cite its references or sources. ... The Space Shuttle External Tank (ET) on its way to the Vehicle Assembly Building. ... The RS-68 (Rocket System 68) is the largest existing liquid hydrogen / liquid oxygen engine, producing a thrust of 650,000 lbf (2. ... For other uses, see Newton (disambiguation). ... Specific impulse (usually abbreviated Isp) is a way to describe the efficiency of rocket and jet engines. ... This article does not cite any references or sources. ... This article does not adequately cite its references or sources. ... The Ares V Earth Departure Stage (EDS) is the high-energy cryogenic upper stage of NASAs proposed new Ares V launch vehicle. ... J-2 Rocket Engine Specifications. ... For other uses, see Newton (disambiguation). ... Specific impulse (usually abbreviated Isp) is a way to describe the efficiency of rocket and jet engines. ... This article does not cite any references or sources. ... This article does not adequately cite its references or sources. ... Comparison of the Saturn V, Space Shuttle and the two Shuttle Derived Launch Vehicles proposed to replace the Shuttle. ... This article is about the American space agency. ... A Saturn V launch vehicle sends Apollo 15 on its way to the moon. ... Project Constellation is NASAs current plan for space exploration. ... Image from NASA site Two planned configurations for a return to the moon, heavy lift (left) and crew (right) The Vision for Space Exploration is the United States space policy announced on January 14, 2004 by President George W. Bush. ... NASAs Space Shuttle, officially called Space Transportation System (STS), is the United States governments current manned launch vehicle. ...

Safer, Simpler, Sooner

The proposal would replace the planned Ares I and Ares V with two launch vehicles developed more directly from existing Shuttle components. Proponents assert that DIRECT would cut development, production and annual operations costs roughly in half by reducing the number of new launchers NASA intends to build from two to just one. Combined with minimizing the modification of existing Shuttle components this would also considerably reduce schedules for fielding the new vehicles closing the "gap" in US manned space access after the Space Shuttle retires by two years and also bringing the new return to the moon mission schedule forward two years. It has been suggested that Ares I-1 be merged into this article or section. ... The Ares V (formerly known at the Cargo Launch Vehicle or CaLV) is the cargo launch component of Project Constellation. ... NASAs Space Shuttle, officially called Space Transportation System (STS), is the United States governments current manned launch vehicle. ...

Origins

According to its proponents, DIRECT v1.0 was the product of a three-month grass-roots study produced by nearly 50 NASA engineers and managers working purely in their free time, and a small group of dedicated enthusiasts. The proposal was submitted on October 25, 2006 to NASA's Administrator, Michael D. Griffin, and a wide range of industry, political and advocacy groups involved in the current development plans. v2.0 of the proposal is a 9 month refinement study which was announced on September 19th 2007 at the AIAA "Space 2007" Conference in Long Beach, CA. is the 298th day of the year (299th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... Dr. Michael D. Griffin Dr. Michael Douglas Griffin (born November 1, 1949 in Aberdeen, Maryland) has been the Administrator of NASA since April 13, 2005. ... September 19 is the 262nd day of the year (263rd in leap years). ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... The American Institute of Aeronautics and Astronautics (AIAA) is the scholarly society for the field of aerospace engineering. ...

DIRECT 2.0

On May 10, 2007, a revised DIRECT 2.0 proposal was released by the same volunteer group to meet peer-reviewed critiques of the initial proposal. The revised proposal calls for reducing the development costs and risks of the Vision for Space Exploration program through the use of man-rated versions of existing RS-68 and J-2X rocket engines instead of developing new, upgraded versions of these engines as originally proposed by both DIRECT 1.0 and by the NASA Ares I and Ares V proposals. is the 130th day of the year (131st in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... Image from NASA site Two planned configurations for a return to the moon, heavy lift (left) and crew (right) The Vision for Space Exploration is the United States space policy announced on January 14, 2004 by President George W. Bush. ... The RS-68 (Rocket System 68) is the largest existing liquid hydrogen / liquid oxygen engine, producing a thrust of 650,000 lbf (2. ... J-2 Rocket Engine Specifications. ... This article is about the American space agency. ... It has been suggested that Ares I-1 be merged into this article or section. ... The Ares V (formerly known at the Cargo Launch Vehicle or CaLV) is the cargo launch component of Project Constellation. ...

The Jupiter 232 heavy launch vehicle in the revised DIRECT 2.0 proposal differs from the original proposal primarily by specifying the use of two existing J-2 engines on the Earth Departure Stage (EDS) instead of one new J-2X engine, and 3 man-rated ablative nozzle RS-68 main engines instead of 2 new regeneratively cooled nozzle RS-68 main engines. The Jupiter 120 Crew LV in the revised DIRECT 2.0 proposal specifies the use of 2 existing man-rated ablative nozzle RS-68 main engines instead of 2 new regeneratively-cooled nozzle RS-68 main engines. J-2 Rocket Engine Specifications. ... The Ares V Earth Departure Stage (EDS) is the high-energy cryogenic upper stage of NASAs proposed new Ares V launch vehicle. ... J-2 Rocket Engine Specifications. ... The RS-68 (Rocket System 68) is the largest existing liquid hydrogen / liquid oxygen engine, producing a thrust of 650,000 lbf (2. ... The RS-68 (Rocket System 68) is the largest existing liquid hydrogen / liquid oxygen engine, producing a thrust of 650,000 lbf (2. ... The RS-68 (Rocket System 68) is the largest existing liquid hydrogen / liquid oxygen engine, producing a thrust of 650,000 lbf (2. ... The RS-68 (Rocket System 68) is the largest existing liquid hydrogen / liquid oxygen engine, producing a thrust of 650,000 lbf (2. ...

Proponents of the DIRECT 2.0 proposal argue that the additional performance capacity of the Jupiter 120 Crew LV proposal over the Ares I Crew LV provides sufficient performance margin to substantially increase crew safety through more robust safety systems, including several tons of protective armor between the Orion spacecraft and the fuel and engines of the core stage. Proponents also argue that the use of existing, flight-proven systems derived from the Space Shuttle and Delta IV EELV in DIRECT 2.0 is inherently much safer than the untested new components that would need to be developed for either Ares I or the original DIRECT proposal. It has been suggested that Ares I-1 be merged into this article or section. ... Orion spacecraft in lunar orbit Orion spacecraft with docked LSAM lunar lander Orion spacecraft approaching the ISS Orion during a landing on Earth The Orion Spacecraft (formerly known as the Crew Exploration Vehicle or CEV) is a proposed series of American manned and unmanned spacecraft, intended to replace the Space... NASAs Space Shuttle, officially called Space Transportation System (STS), is the United States governments current manned launch vehicle. ... It has been suggested that some sections of this article be split into a new article entitled Delta IV launches. ... The Evolved Expendable Launch Vehicle (EELV) program was a United States government, primarily a Department of Defense–sponsored effort to develop at least one family of space launch vehicles, that would meet the long term needs of the military. ... It has been suggested that Ares I-1 be merged into this article or section. ...

Advantages and disadvantages

Proponents of DIRECT also argue that this proposal will enable NASA to fulfill the mandate of the Vision for Space Exploration faster, safer, and sooner than the planned Ares I and Ares V, at a much lower cost and with far less programmatic risk. Unlike the budget plans for Ares I and Ares V, DIRECT will still allow NASA sufficient room in its current budgets beyond launch vehicle development and operations to continue funding other missions such as the International Space Station beyond 2016, while being better able to withstand the unpredictability of future annual congressional/administration budget allocations. Image from NASA site Two planned configurations for a return to the moon, heavy lift (left) and crew (right) The Vision for Space Exploration is the United States space policy announced on January 14, 2004 by President George W. Bush. ... It has been suggested that Ares I-1 be merged into this article or section. ... The Ares V (formerly known at the Cargo Launch Vehicle or CaLV) is the cargo launch component of Project Constellation. ... “ISS” redirects here. ...

The DIRECT proposal calls for NASA to use the massive development-cost and fixed-cost savings from DIRECT to accelerate the VSE's schedule for returning to the moon, to continue to fly missions to support the International Space Station, and to potentially fly other missions such as servicing missions to the Hubble Space Telescope. Like NASA's official Constellation plans, the DIRECT proposal calls for ensuring that the existing NASA Space Shuttle industrial base and workforce at sites around the U.S. would be retained (which is important from both the standpoint of maintaining Congressional support and maintaining the skills and know-how of this workforce). However, compared to Constellation, the much shorter gap in manned U.S. space flight under DIRECT would prevent the type of knowledge-loss that NASA suffered in the gap between Apollo and the Shuttle in the late 1970's and the related localized economic hardship in Florida's Space Coast that was seen during the same time period. Image from NASA site Two planned configurations for a return to the moon, heavy lift (left) and crew (right) The Vision for Space Exploration is the United States space policy announced on January 14, 2004 by President George W. Bush. ... “ISS” redirects here. ...

Opponents of DIRECT argue that the safety factor of this proposal is not as good as that of the original ESAS Crew LV proposal. DIRECT's proponents counter that the Jupiter 120 Crew LV has much greater safety margins than NASA's current plans for an Ares I Crew LV, which is a significantly different vehicle from the originally selected ESAS Crew LV. Opponents also contend that, as a plan developed outside of official NASA channels (NIH), DIRECT stands little chance of being implemented. The Exploration Systems Architecture Study (ESAS) is the official title of a large-scale, system level study conducted by the National Aeronautics and Space Administration (NASA) during the Summer of 2005 in response to the American president George W. Bushs announcement on January 14, 2004 of his goal of... This article does not cite any references or sources. ...

Design

The DIRECT 1.0 Launch Vehicle and its heritage.

The DIRECT launch vehicle concept consists of a core stage, based on many existing elements of the current External Tank with either two or three Pratt & Whitney/Rocketdyne RS-68 main engines mounted directly underneath, and a pair of Alliant Techsystems 4-segment Solid Rocket Boosters (SRBs) unchanged from the Space Shuttle today. According to its proponents, initial performance to Low Earth Orbit (LEO) [specifically to 42x120nm, 28.5-degree inclination initial orbit] for this initial variant of the DIRECT Crew LV is conservatively expected to be at least 46,635kg (102,812lb), which is 250% of Ares I's 19,300kg (42,500lb) maximum performance. This means that an Orion spacecraft could be launched on top of the vehicle, along with 24,600kg (54,000lb) of additional cargo on every flight - a useful capability that is impossible with the Ares I. Image File history File links Size of this preview: 800 × 404 pixelsFull resolution (2905 × 1468 pixel, file size: 397 KB, MIME type: image/jpeg) Unlike Ares, DIRECT shares significant, immediate commonality with existing Space Shuttle hardware that flies today. ... Image File history File links Size of this preview: 800 × 404 pixelsFull resolution (2905 × 1468 pixel, file size: 397 KB, MIME type: image/jpeg) Unlike Ares, DIRECT shares significant, immediate commonality with existing Space Shuttle hardware that flies today. ... Diagram of Space Shuttle External Tank showing internal structure The Space Shuttle External Tank (ET) contains the liquid hydrogen fuel and liquid oxygen oxidizer and supplies them under pressure to the three space shuttle main engines in the orbiter during lift-off and ascent. ... The RS-68 (Rocket System 68) is the largest existing liquid hydrogen / liquid oxygen engine, producing a thrust of 650,000 lbf (2. ... The Space Shuttle Solid Rocket Booster (SRB) is the rocket that provides 83% of liftoff thrust for the Space Shuttle. ... A low Earth orbit (LEO) is an orbit in which objects such as satellites are below intermediate circular orbit (ICO) and far below geostationary orbit, but typically around 350 - 1400 km above the Earths surface. ... It has been suggested that Ares I-1 be merged into this article or section. ... Orion spacecraft in lunar orbit Orion spacecraft with docked LSAM lunar lander Orion spacecraft approaching the ISS Orion during a landing on Earth The Orion Spacecraft (formerly known as the Crew Exploration Vehicle or CEV) is a proposed series of American manned and unmanned spacecraft, intended to replace the Space...

An optional upper stage, known as the Earth Departure Stage (EDS), powered by two Pratt & Whitney/Rocketdyne J-2XD engines would be used to increase payload capacity for certain missions. Payload performance to LEO increases to at least 103,342kg (227,829lb). The Ares V Earth Departure Stage (EDS) is the high-energy cryogenic upper stage of NASAs proposed new Ares V launch vehicle. ... J-2 Rocket Engine Specifications. ...

Gross performance for the two Ares I and Ares V launchers required for every Lunar mission is expected to be no more than 150,900kg (333,000lb). By comparison, two DIRECT J-232 vehicle, one launching Crew and spacecraft and the other launching mostly propellant, are capable of launching in excess of 220,000kg (485,000lb), including greater performance margin reserves.

To speed development of DIRECT, the RS-68 engines on the core stage would be man-rated versions of those used successfully on the current Delta 4 program. DIRECT explicity plans not to require performance upgrades, even rejecting the 6% additional performance NASA requires from the RS-68 for use on the Ares V instead opting to operate the engines at the lower performance levels being used today to gain maximum possibly reliability and safety. The RS-68 (Rocket System 68) is the largest existing liquid hydrogen / liquid oxygen engine, producing a thrust of 650,000 lbf (2. ... It has been suggested that some sections of this article be split into a new article entitled Delta IV launches. ... The Ares V (formerly known at the Cargo Launch Vehicle or CaLV) is the cargo launch component of Project Constellation. ...

Unlike NASA's Ares I, DIRECT does not require any new engines to be developed for the first vehicle, designated J-120, in order to fly the first manned Orion spacecraft. This removes the greatest cost and schedule impacts that Ares I faces. J-2XD engines are only required by DIRECT on the optional upper stage for the later lunar missions. Even then DIRECT would only require the lower-thrust, lest-costly J-2X "Development" variant. DIRECT does not require the additional performance of the fully upgraded J-2X engine needed by both Ares I and Ares V. Orion is a spacecraft currently under development by the United States National Aeronautics and Space Administration (NASA). ... J-2 Rocket Engine Specifications. ...

Similarly, DIRECT does not require the very expensive development of new 5-segment Solid Rocket Boosters as needed by Ares I and Ares V. The existing fully man-rated 4-segment Shuttle SRB's provide adequate thrust for DIRECT while helping to reduce costs. The Space Shuttle Solid Rocket Booster (SRB) is the rocket that provides 83% of liftoff thrust for the Space Shuttle. ...

Finally, DIRECT's Core Stage uses the existing 8.41m diameter of the Shuttle's External Tank. Unlike Ares V with its 10.06m diameter Core Stage, this allows DIRECT to re-use the existing manufacturing tooling for the External Tank at the Michoud Assembly Facility, the existing Pegasus barge used to transport the tank from Michoud to Kennedy Space Center, the existing work platforms in the Vehicle Assembly Building, the existing Mobile Launch Platforms and Crawler-Transporters, and much of the structure of the existing Fixed Service Structure and Flame Trenches at Launch Complex 39. The Space Shuttle External Tank (ET) on its way to the Vehicle Assembly Building. ... Michoud Assembly Facility in 1968 The Michoud Assembly Facility is an 832 acre (3. ... Merritt Island and Kennedy Space Center (shown in white). ... The Vehicle (originally Vertical) Assembly Building, or VAB, is a very large building located at in NASAs Kennedy Space Center, halfway between Jacksonville and Miami, and due east of Orlando on Merritt Island, on the Atlantic coast of Florida. ... An MLP being carried by a Crawler-Transporter. ... Crawler-transporter #2 (Franz) in a December 2004 road test after track shoe replacement. ... Launch Complex Plan - 1963 Launch Complex 39A Launch Complex 39B with Discovery shuttle Launch Complex 39 actually refers to LC39A and LC39B at the John F. Kennedy Space Center on Merritt Island in Florida, USA, which are currently launch pads for the space shuttle. ...

While DIRECT does not require any of the upgraded hardware needed by the Ares launchers, should additional performance be required in the future DIRECT can take advantage of these enhancements to increase performance - but they are not requirements in the critical path to success and the additional capital investment is not required.

Design History

The basic concept is not new. It was first proposed in 1986 by NASA's Marshall Space Flight Center in the aftermath of the Space Shuttle Challenger disaster. It was promoted as one of the most logical alternatives for launching unmanned cargo and even potentially a re-started Apollo spacecraft program if required. There were, however, no funds available to NASA for building any new vehicles, so the idea was shelved and NASA concentrated on fixing and operating the Space Shuttle program instead. Aerial view of the test area at Marshall Space Flight Center The George C. Marshall Space Flight Center (MSFC) is a lead NASA center for propulsion, Space Shuttle propulsion, external fuel tank, crew training and payloads, International Space Station (ISS) design and construction, for computers, networks, and information management. ... The iconic image of Space Shuttle Challengers smoke plume after its breakup 73 seconds after launch. ... Apollo Spacecraft: Command Module, Service Module, Lunar Module. ...

In 1991 the National Launch System brought the idea back to life. Proposed by NASA and the DoD as an alternative to the Titan IV. The design was based on the same SRB's as Shuttle, the same core tanking, but it had four smaller, inexpensive engines and considerably lower performance than the original concept. The Titan IV family (including the IVA and IVB) of space boosters are used by the US Air Force. ...

Then in 2005, NASA's Exploration Systems Architecture Study (ESAS) included a very similar design, but with three of the Space Shuttle Main Engines (SSME). Known as LV-24 in Crew launch form, and LV-25 in Cargo configuration, the idea was dismissed because it did not have sufficient performance for the proposed lunar program - however the concept was not considered using an EDS. The Exploration Systems Architecture Study (ESAS) is the official title of a large-scale, system level study conducted by the National Aeronautics and Space Administration (NASA) during the Summer of 2005 in response to the American president George W. Bushs announcement on January 14, 2004 of his goal of... Space Shuttle Main Engine cluster The Space Shuttle Main Engines (SSMEs) are the three main engines on the Space Shuttle orbiter. ...

DIRECT takes the final ESAS recommendation of using the EDS during the ascent phase of the flight to gain additional launch performance on the Cargo LV, and applies this same methodology to the basic LV 24/25 design - at which point LV-24/25 considerably out-performs the ESAS's final solutions for Lunar missions. The Exploration Systems Architecture Study (ESAS) is the official title of a large-scale, system level study conducted by the National Aeronautics and Space Administration (NASA) during the Summer of 2005 in response to the American president George W. Bushs announcement on January 14, 2004 of his goal of...

The next change in DIRECT's development was in response to NASA dropping the SSME on their Cargo LV design. This was due to the high manufacturing cost of the SSME engines, and the difficulty in producing the required number of units per year with existing manufacturing facilities. So NASA chose to replace them with five RS-68 engines to make the Ares V Cargo LV. This same change was also applied to DIRECT's concept. Analysis showed, however, that the number of engines required for this particular vehicle could be reduced to just two of the basic RS-68 engines. Additional performance and IMLEO could be provided by upgrading the main engines with the Regenerative Cooling Nozzles to improve their efficiency. It should be noted, however, that the analysis also demonstrated that this improvement, while desirable, is not required in order to accomplish the basic missions of both the crew and cargo programs. Space Shuttle Main Engine block The Space Shuttle orbiter has three main engines. ... Space Shuttle Main Engine block The Space Shuttle orbiter has three main engines. ... The RS-68 (Rocket System 68) is the largest existing liquid hydrogen / liquid oxygen engine, producing a thrust of 650,000 lbf (2. ... The Ares V (formerly known at the Cargo Launch Vehicle or CaLV) is the cargo launch component of Project Constellation. ... Regenerative cooling in rockets is where the propellant is passed through tubes around the combustion chamber or nozzle as the fuel is a good conductor of heat. ...

Integrated Approach

Once the basic vehicle was pinned down, more NASA engineers and managers started to support the concept and offer their time to flesh out the concept from a wider perspective. These professionals contributed to creating a complete cost analysis comparison, a detailed series of evaluations for supporting facilities such as data on the existing manufacturing facilities for the External Tank at the Michoud Assembly Facility and the various launch-processing facilities currently at the Kennedy Space Center. The Space Shuttle External Tank (ET) on its way to the Vehicle Assembly Building. ... Michoud Assembly Facility in 1968 The Michoud Assembly Facility is an 832 acre (3. ... Merritt Island and Kennedy Space Center (shown in white). ...

From these contributions, a clear difference in cost, schedule, maintenance, manufacturing & launch processing flow became apparent between the Ares and DIRECT approaches. DIRECT would re-use almost all of the existing facilities, whereas Ares I and Ares V each required seriously overhauled or completely replaced facilities – and each required its own set. This impacts almost every aspect of the operation from cost to design, development, testing, evaluation, implementation, schedule, risk mitigation, workforce retention and safety. It has been suggested that Ares I-1 be merged into this article or section. ... The Ares V (formerly known at the Cargo Launch Vehicle or CaLV) is the cargo launch component of Project Constellation. ...

A fully integrated assessment of all these factors, under the outlines of the political requirements NASA must operate within, and a detailed analysis of the wider range of Lunar mission procedures which DIRECT can offer, resulted in the complete DIRECT Launch Vehicle Proposal.

Criticism and Changes

The original DIRECT 1.0 proposal created a wave of discussion within both professional NASA/aerospace circles and within the broader community of NASA supporters and enthusiasts. Approximately 2000 posts about DIRECT 1.0 appeared on the public forum at NASASpaceflight.com over a 7 month period.

In late 2006, NASA's Dr. Doug Stanley declared that the DIRECT 1.0 proposal could not work as it relied on overly-optimistic and speculative performance specifications for an upgraded RS-68 Regen engine. Dr. Stanley produced official specifications from Pratt & Whitney/Rocketdyne about the RS-68 Regen upgrades to prove his point. Later evidence from PWR concluded that DIRECT 1.0's overly-optimistic RS-68 variant was in fact technically possible, although was going to be expensive and time-consuming to develop.

The DIRECT team took this and other criticisms about the initial proposal into account in early 2007. After several months of work, the team came back with a revised proposal, DIRECT 2.0. To address criticism of relying on engine studies rather than working engines, DIRECT 2.0 uses only man-rated versions of the existing RS-68 with no performance upgrades at all and the lower of two specifications of J-2X engine which Pratt & Whitney/Rocketdyne are currently developing for NASA's Ares launchers. DIRECT 2.0introduced a scalable, modular family of Shuttle-derived launch vehicles, starting with the DIRECT Jupiter-120 and DIRECT Jupiter-232.

DIRECT 2.0 was further expanded in September 2007 with a 130 page study, covering 9 months of refinement into the concept, at the AIAA "Space 2007" Conference in Long Beach, CA. in which the launch vehicles were presented as a single part of a much wider reaching architecture enabling the US to maintain the ISS, progress on to the moon with larger missions than Ares I and Ares V can perform, and presented the wide range of options available to evolve the program using DIRECT launchers to achieve the goals of the Mars program which will follow eventually. The paper also considered many other options which are enabled by DIRECT, such as Lagrangian point staging architecture options and mission architectures for visiting Near-Earth object destinations. The American Institute of Aeronautics and Astronautics (AIAA) is the scholarly society for the field of aerospace engineering. ... “ISS” redirects here. ... A contour plot of the effective potential (the Hills Surfaces) of a two-body system (the Sun and Earth here), showing the five Lagrange points. ... Near-Earth objects (NEO) are asteroids, comets and large meteoroids whose orbit intersects Earths orbit and which may therefore pose a collision danger. ...

References

External links

• Direct Launch Vehicle: DIRECT proposal website
• v2.02 PDF Proposal
• TheSpaceReview.com commentary on ESAS including DIRECT
• TheSpaceReview.com article about DIRECT
• Q&A: ESAS Lead - Dr Doug Stanley (On DIRECT)
• DIRECT v1.0 discussion on NASASpaceFlight.com
• DIRECT v2.0 discussion on NASASpaceFlight.com
• AIAA Space 2007 Conference presentation in low res or hi res
• TheSpaceShow.com interview about DIRECT