DIRECT

For other uses, see Direct.

DIRECT - Jupiter Launch Vehicle

Function	Partially re-usable launch vehicle
Manufacturer	None
Country of origin	United States
Size
Height	80.4 to 108.1m (263ft 9in to 354ft 8in)
Diameter	8.41 m (identical to Shuttle External Tank) (27ft 7in)
Mass	2,033,472 to 2,390,708 kg
Stages	2 or 3
Capacity
Payload to LEO	41,121 to 111,254 kg (90,655 to 220,746 lb)
Launch history
Status	Proposal
Launch sites	LC-39, Kennedy Space Center
Type of passengers/cargo	Orion EDS LSAM
Boosters - Shuttle SRB
No. boosters	2
Engines	1 solid
Thrust	13,982 kN (3,142,302 lbf)
Specific impulse	269.1 sec
Burn time	123.8 seconds
Propellant	solid
First stage (Jupiter-120 Variant) - Core Stage based on Shuttle External Tank
Engines	(2 RS-68 "Ablative")
Thrust	6,686 kN (1,502,000 lbf)
Specific impulse	409.0 sec
Burn time	494.8 sec
Propellant	LOX/LH2
First stage (Jupiter-232 Variant) - Core Stage based on Shuttle External Tank
Engines	(3 RS-68B "Ablative")
Thrust	10,639 kN (2,391,000 lbf)
Specific impulse	414.2 sec
Burn time	279.8 sec
Propellant	LOX/LH2
Second stage (Jupiter-232 Variant) J-232 EDS
Engines	2 J-2X
Thrust	2,616 kN (588,000 lbf)
Specific impulse	448.0 sec
Burn time	423.9 sec
Propellant	LOX/LH2

DIRECT is a proposal outlining an alternative architecture for supporting the Vision for Space Exploration. The cornerstone of the proposal is to replace the two new Ares I and Ares V launch vehicles with a single "Jupiter" launch system. The Jupiter system would have greater commonality with the existing Space Shuttle systems in order to reduce costs, schedule and technical requirements.

As of September 2008, the DIRECT Team consists of 69 members, 62 of whom are NASA and NASA-contractor engineers and managers from the Constellation Program volunteering their expertise in their spare time, along with 7 non-NASA "front men" who provide the public face of the group.

The name "DIRECT" refers to the use of components with a more direct heritage to the existing Space Shuttle designs. The Jupiter launch vehicle is sometimes referenced in media reports as the DIRECT v2.0 rocket, although DIRECT more properly refers to the larger-scope architecture.

Overview

Some of the many configurations possible with the Jupiter Launch Vehicle Family.

The DIRECT architecture proposes that the twin Ares I and Ares V launchers be replaced with a single launch vehicle named "Jupiter". Instead of utilizing two different rockets to perform the duties of crew and cargo launch, a single design of launch vehicle would be flown in two different configurations - the key difference essentially being whether it flies with or without an Upper Stage - to perform all of the same missions.

The core of all Jupiter vehicles is based around exactly the same configuration. All variants use a pair of Space Shuttle Solid Rocket Boosters unchanged from their configuration as used today on Shuttle. Mounted between those is the Jupiter Core Stage, based very closely on the existing Space Shuttle External Tank, modified to mount payloads on top and a set of engines underneath. The arrangement of engine mountings will support up to three RS-68 main engines, but for some configurations only the outboard two are fitted, with the central engine removed and all plumbing and electrical connections capped.

There are many different theoretical configurations of Jupiter possible, but the DIRECT proposal centers around two primary configurations; the Jupiter-120 with over 40 metric T of lift performance and the Jupiter-232 with over 111 mT of performance.

Naming Convention

The nomenclature used to identify configurations is a three-digit code, such as 120 or 232. The first digit refers to the number of Cryogenic Stages used by the vehicle to reach orbit (Note that this does not include any cryo stages designed to be used only in space as they would be considered part of the payload). The second digit refers to the number of main engines fitted on the Core Stage. The final digit refers to how many engines are fitted on the Upper Stage, or 0 if there is no Upper Stage. Additional digits can be added if extra stage configurations are ever needed in the future.

Proposed Configurations

The Jupiter-120 (1 cryo stage, 2 core stage engines, no upper stage engines) is the first proposed configuration. It is intended to be relatively simple develop in order to become fully operational in 2013 so as to shorten the gap after the retirement of the Space Shuttle to the minimum possible. Jupiter-120 consists of the Core vehicle alone, fitted with just a pair of RS-68's and a large Payload Fairing on top. This small configuration can lift over 40 mT of payload to orbit, of which the 20 mT Orion spacecraft carrying a crew would be roughly half. Jupiter-120 would therefre be capable of replacing the most useful capabilities of the Space Shuttle by allowing crew to be launched along with approximately 20 mT of useful payload. Unlike the Shuttle, however, crew safety would not be compromised as the cargo would remain seperate from the crew spacecraft, which would have a Launch Abort System capable of pulling the crew capsule to safety in the event of an abort.

The Jupiter-232 (2 cryo stages, 3 core stage engines, 2 upper stage engines) would follow in around 2016-2017 with a performance envelope above 111 mT, designed to support the efforts to return humans to the surface of the Moon, and to support the first human exploration of Mars and other destinations beyond.

Crew Safety

The Jupiter launch vehicles have five main safety features:

• The Jupiter design re-uses the proven method of Space Shuttle to safely attach the SRB's, avoiding all of the severe vibration problems which the Ares I design is experiencing in the form of thrust oscillation.

• The Jupiter's main engines are ignited on the ground. Any start-sequence problems can then be detected before committing to the launch.

• With multiple engines on all stages, one of the engines can be safely shut down after a non-catastrophic failure without aborting the mission. Some Jupiter flight configurations offer the ability to survive engine-out situations starting as early as 45 seconds after launch.

• Located at the top of a large payload fairing, just like the Saturn V, the Orion spacecraft is always at least 10 meters (33ft) further away from the stages filled with fuel than it would be on an Ares I. This provides an additional "buffer space" between an exploding vehicle and the crew in any catastrophic failure situations.

• With approx. 20mT of additional cargo performance any Orion crew flight which would not be utilizing all of its payload capacity could be flown with additional protective hardware inside the payload fairing, mounted below the spacecraft. Options include flying with a composite panel made from boron-carbide and Kevlar, designed to create a light-weight "bullet proof vest" between the spacecraft and the stages below. Another option is to fit a full-width tank filled with water, which could act as a shield to protect the spacecraft from high-velocity shrapnel during a disaster.

The currently baselined Ares V configuration, with 6 RS-68B main engines and 5.5segment SRB's has a Loss of Mission (LOM) risk factor below 1 in 90 and a Loss of Crew (LOC) risk factor below 1 in 850. The ESAS Report specified that an LOC of 1 in 1000 (a figure estimated to be at least five times higher than the Space Shuttle today, even accounting for the latest safety upgrades) would be the minimum required to be acceptable for human use for any new systems, using this issue to dismiss vehicles from consideration such as the Atlas V. Because Ares V will not meet NASA's targets regarding human safety all Ares-based missions will be forced to utilize an Ares I, incurring all of its associated costs for every mission type.

However, being considerably smaller and with fewer engines even the larger Jupiter variant, the Jupiter-232, is expected to comfortably exceed these targets with an LOC of 1 in 1162. This allows both the small and the large configurations of Jupiter launcher to fly safely with crew. The flexibility this offers is considerable, as is the additional performance offered by flying two large boosters instead of only one large and one small booster for all lunar missions.

Program Risk

Proponents of DIRECT contend that the high costs and continually growing schedule for both Ares I and Ares V are leading the current efforts towards cancellation. Parallels are drawn between Ares and the many previous NASA programs which have been cancelled, such as the X-33/Venture Star development, the Orbital Space Plane, the First Lunar Outpost, the Space Launch Initiative and even the premature termination of the historically successful, but brief, Apollo Program - all terminated due to high costs and/or severe delays to their schedules.

One of the strongest programmatic criticisms with the current Ares I and Ares V architecture is the high cost for both developing two new launchers and for operating two concurrent programs. The cost concerns have been cited in GAO Reports to Congress noting that the Ares I alone is expected to cost up to $14.4 billion to develop. NASA Administrator Michael D. Griffin confirmed that the total cost for developing both Ares launchers would be $32 billion, clearly indicating that the Ares V will be even more expensive to develop than the Ares I.

The schedule for the simpler Ares I launcher continues to slip ever-further to the right. From the original intent in the Exploration Systems Architecture Study (ESAS) Report proposing crewed CEV flights as early as mid-2011, the schedule has been pushed-back by more than a year for every year of work so far done on the system. 3 years later, the current NASA schedule has slipped by more than 4 years with the very first test-crewed flight of Orion - Orion 2 – now with no that 65% confidence of occurring as early as September 2015 meaning that the first fully operational flight - Orion 4 - will not now occur until March 2016 at the soonest.

DIRECT contends that the requirement to develop so much new hardware for Ares I in order to fly the first Orion is directly responsible for pushing the schedule so far to the right and that this is driving up the development costs. Specifically, the requirement to develop the brand-new 5-segment version of the Space Shuttle SRB, a brand-new J-2X engine, a brand-new Upper Stage, all-new manufacturing at the Michoud Assembly Facility and new launch facilities at Kennedy Space Center are all contributing to this constant slippage.

Comparatively, to fly the Orion sooner, DIRECT proposes a launcher which re-uses the existing 4-segment Space Shuttle Solid Rocket Boosters which are already fully qualified for human use, uses the existing RS-68 main engine needing to be only re-qualified for human use, re-uses all of the existing manufacturing to build a modified variant of the existing Space Shuttle External Tank and only requires moderate modifications at Kennedy Space Center to enable launches.

The key program risk, according to DIRECT, is that NASA's Ares I is already over-budget, late and is lacking in performance, so when serious funding is required for the much larger and more expensive Ares V, Congress is not likely to be impressed. The risk is that Congress may pull the budgetary plug on the Heavy Lift effort before it is complete. This would leave NASA with a very expensive, yet small, Ares I launcher and no heavy-lift capability to enable any Lunar or Martian exploration programs in the future. NASA would then be locked into small missions incapable of venturing beyond Low Earth Orbit, and would have a small launch system comparable in performance to the Delta-IV Heavy EELV, but costing four or five times as much to operate each year.

DIRECT’s proposal for a single launch vehicle entirely removes the program risks associated with the possible cancellation of any second launcher. The brand-new J-2X is still needed to go to the Moon around 2017, but is not required to support the initial Orion crew flights to the International Space Station (ISS) around 2013.

Schedule

The long-pole of the Ares I development effort is currently the schedule for the J-2X Upper Stage engine. Second is the development of the 5-segment version of the SRB, after that, the third major item driving the schedule is the constant revisions needed to the Orion spacecraft to get it light enough to fit within the Ares I's performance envelope while strengthening it due to the Thrust Oscillation concerns. These two factors have resulted in the contractor, Lockheed Martin, requesting that NASA fixes the Ares I and stops impeding their design progress. Latest information indicates this process has resulted in setting back the entire Orion program, from a relatively complete Cycle-3 effort, back to the beginning of a brand-new Cycle-2 effort in order to try to change the primary structure of the Crew Module from Aluminum-Lithium to a lighter-weight composite material. This change has already pushed the Preliminary Design Review (PDR) milestone date back by more than a year to February 2010 and promises to add a considerable amount of additional development cost and production costs to an already-over-budget Orion Project.

DIRECT's Jupiter launchers avoid all these delays by firstly not requiring the J-2X at all on the first generation of the Jupiter-120 vehicle, by not requiring the 5-segment SRB at all and by providing more than 40mT of lift performance allowing the Orion design to be solidified today and go straight on to PDR unhindered in November 2008 as originally planned.

In addition, by removing the parallel development of the Ares V booster, DIRECT removes a complete layer of high development costs from the budget requirements. Most of this money would be re-used to speed development work of the other elements, Orion, Jupiter-120, launch facility modifications and all associated systems. A significant cash injection is expected to allow the schedules of all those elements to be significantly trimmed allowing an initial crew launch to occur in 2012 and full operational capability of an Orion/Jupiter-120 system to perform 6-person crew rotations and cargo deliveries at the ISS in early 2013 - three years ahead of the current Ares I schedule.

Workforce

Artists impression of an Orion spacecraft taking a DIRECT Space Shuttle Payload Delivery Module (SSPDM) to the International Space Station in 2013, carrying an airlock, the $1.5bn AMS Experiment and some other cargo - all which could be launched on a single Jupiter-120.

An additional aspect of the DIRECT proposal is to utilize some of the extra cash made available by removing the need for a second launcher, to fund additional projects intended to make use of the extra performance of the Jupiter-120. The 20mT of extra payload capability of the Jupiter-120 allows for a range of additional cargo payloads to be flown with each Orion crew, a capability which is not possible with the Ares I. The DIRECT Team have suggested a number of extra missions which would be enabled by Jupiter in their proposal, including:-

• New ISS resupply missions delivering the 3 Italian-built Multi-Purpose Logistics Module's in 2012, 2013 and 2014
• Performing even more Hubble Space Telescope Servicing Missions with Orion crews around 2015
• Launching massive new space telescopes over 8 meters in diameter (twice the diameter and 4 times the resolution of Hubble)
• Perform NASA's Mars Sample Return mission on a single Jupiter launcher, to land on Mars and return a sample of its soil back to Earth for study as early as 2013
• Launching a human crew to fly around the moon as early as 2013

This wide range of new missions can be planned and afforded if only one new launcher is being developed instead of two. The new missions and payloads would all require new contracts, providing useful employment for many of the experienced people who will otherwise be laid-off at the end of the Space Shuttle Program in 2010. Instead of being released, thousands of these knowledgeable and skilled people would be required for building, preparing and processing all the additional payloads. And such employment would keep those valuable skills and knowledge within the agency until the Lunar phase is ready to pick up their contracts around 2016-2018 to support the new Lunar base and Lunar Lander projects. Essentially this approach provides a “bridge” to help transition the thousands of experienced staff across the gap and avoid a devastating repeat of the Apollo Program to Space Shuttle "brain-drain" which occurred in the 1975-1981 period.

Origins

A 1978 image of a Morton Thiokol-proposed In-Line Shuttle Derived Launch Vehicle concept - Note the "white" tanking

The basic concept behind DIRECT has been around since the inception of the Space Shuttle Program. Drawings and artwork of an In-Line Shuttle stack configuration date back to 1978 – 3 years before the first Shuttle flight.

The first official trade study was conducted 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 would have potentially allowed a re-started Apollo spacecraft program as well. There were, however, no funds available to NASA for building any new vehicles while the Space Shuttle Program continued. The idea was shelved and NASA concentrated on fixing and operating the Space Shuttle instead.

Of all the previous studies and development efforts, DIRECT bears the strongest relationship to the 1991 National Launch System effort. Proposed jointly by NASA and the Department of Defense as an alternative to the Titan IV, the design was based on the same SRB’s as Shuttle and the same core tanking, but it had four inexpensive engines and considerably lower performance than the original concept. But again, Congress did not appropriate funding for the development while Shuttle continued to be operated, so the work never proceeded beyond the design phase. A great deal of reference material exists in the public domain regarding NLS.

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 Earth Departure Stage (EDS) and no versions were investigated powered by the less costly, but higher thrust RS-68 engines.

DIRECT v1.0

According to its proponents, DIRECT v1.0 was the product of a three-month grass-roots study produced by more than a dozen NASA engineers and managers working purely in their free time, and a small group of dedicated enthusiasts. 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 LV-24/25.

The next change in DIRECT's development was in response to NASA dropping the Space Shuttle Main Engine 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 Initial Mass in Low Earth Orbit (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.

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 19 2007 at the AIAA "Space 2007" Conference in Long Beach, CA.

Criticism and Changes

The original DIRECT v1.0 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 v1.0 appeared on the public forum at NASASpaceflight.com over a 7 month period.

In late 2006, head of the ESAS Study, Dr. Doug Stanley, declared that the DIRECT v1.0 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 Pratt & Whitney, Rocketdyne confirmed that DIRECT v1.0's “overly-optimistic” RS-68 variant was in fact technically achievable, although was going to be expensive and time-consuming to develop.

DIRECT v2.0

On May 10 2007, a revised DIRECT v2.0 proposal was released by the same volunteer group to meet peer-reviewed critiques of the initial proposal. To address criticism of relying on engine studies rather than working engines, DIRECT v2.0 uses only man-rated versions of the standard performance RS-68 as flown on existing Delta IV launchers, with no performance upgrades at all and the lower of two specifications of J-2X engine which Pratt & Whitney, Rocketdyne were currently developing for NASA's Ares launchers. DIRECT v2.0 introduced a scalable, modular family of Shuttle-derived launch vehicles, starting with the DIRECT Jupiter-120 and DIRECT Jupiter-232.

The Jupiter-232 heavy launch vehicle in the revised DIRECT v2.0 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, and 3 human-rated ablative nozzle RS-68 main engines instead of 2 new Regenerative Cooling Nozzle RS-68 main engines. The Jupiter-120 Crew LV in the revised DIRECT v2.0 proposal specifies the use of 2 existing man-rated ablative nozzle RS-68 main engines instead of 2 new Regenerative Cooling Nozzle RS-68 main engines.

DIRECT v2.0 was further expanded in September 2007 with a 9-month study culminating in a 131 page exploration architecture study released at the AIAA "Space 2007" Conference in Long Beach, CA. The 131 page paper detailed specifically how the launch vehicles were a single part of a much wider-reaching architecture designed to enable the US to maintain the ISS, progress on to the moon with even larger missions than Ares I and Ares V could perform, and presented the wide range of additional capabilities available to evolve the program using Jupiter launchers to achieve the goals of the future 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..

Advantages and disadvantages

Proponents of DIRECT also argue that this proposal will enable NASA to fulfil 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.

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 1970s and the related localized economic hardship in Florida's Space Coast that was seen during the same time period.

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.

David King, director of NASA's Marshall Space Flight Center said that NASA has considered DIRECT and many other rocket proposals were considered, and the Ares family is the right set of rockets for the mission. "DIRECT v2.0 falls significantly short of the lunar lander performance requirement for exploration missions as specifically outlined in Constellation Program ground rules. The concept also overshoots the requirements for early missions to the International Space Station in the coming decade. These shortcomings would necessitate rushed development of a more expensive launch system with too little capability in the long run, and would actually increase the gap between space shuttle retirement and development of a new vehicle. Even more importantly, the Ares approach offers a much greater margin of crew safety - paramount to every mission NASA puts into space."

Design

Exploded Diagram of the Jupiter-120 configuration

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.

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).

Exploded Diagram of the Jupiter-232 configuration

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 IV program. DIRECT explicitly 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 the maximum possible reliability and safety.

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, less-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.

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.

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 Launcher Platforms and Crawler-Transporters, and much of the structure of the existing Fixed Service Structure and Flame Trenches at Launch Complex 39.

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.

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.

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.

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.

References

• Article about DIRECT on American Institute of Aeronautics and Astronautics website
• NASASpaceFlight.com article on DIRECT
• 85 Unclassified Technical Documents about the National Launch System (NLS) - the 1991 NASA/USAF Predecessor which DIRECT is based upon
• v2.0.1 Updated PDF Baseline Proposal
• AIAA Space 2007 Conference presentation in High Res

External links

• DIRECT Launcher proposal website
• v2.0.2 Updated PDF Baseline Proposal
• AIAA Space 2007 Conference presentation in High Res or Low Res
• TheSpaceReview.com commentary on ESAS including DIRECT
• TheSpaceReview.com article about DIRECT
• DIRECT v1.0 discussion on NASASpaceFlight.com (now locked at 131 pages)
• DIRECT v2.0 discussion on NASASpaceFlight.com (now locked at 250 pages)
• DIRECT v2.0 Thread 2 discussion on NASASpaceFlight.com (current discussion ongoing)
• TeamVision page about DIRECT
• Q&A: ESAS Lead - Dr Doug Stanley (On DIRECT)
• TheSpaceShow.com interview about DIRECT, 07/01/2007 issue
• TheSpaceShow.com interview about DIRECT, 02/17/2008 issue and related presentation in PDF
• TheSpaceReview.com article about DIRECT by Stephen Metschan, "There is a better way forward" Part One and Part Two
• Orlando Sentinel article about DIRECT : "NASA remains silent on rocket that could rescue the Cape"
• International Space Development Conference presentation in PPS
• Saving America's Space Program - The Space Review Aug 11, 2008