User:Fotoguzzi/direct edits

DIRECT is a proposed alternative Shuttle-Derived Launch Vehicle (SDLV) architecture supporting NASA's Vision for Space Exploration, [which would (intended to?)] replace the planned Ares I and Ares V with a family of rockets dubbed "Jupiter".

DIRECT is advocated by a grassroots group of space enthusiasts (the "DIRECT Team") who claim to represent a broader team of dozens of NASA and space industry engineers who actively work on the proposal on a volunteer basis. As of September 2008, the DIRECT Team was said to consist of 69 members, 62 of whom were NASA engineers, NASA-contractor engineers, and managers from the Constellation Program volunteering their expertise in their spare time, remaining anonymous due to career concerns, while seven non-NASA members of the team were providing the public face of the group.

The project name "DIRECT" refers to a philosophy of maximizing re-use of hardware and facilities with more direct heritage to those of today's Space Shuttle. The DIRECT Team asserts that using this approach to develop and operate a family of high-commonality rockets would reduce the costs, shorten the schedules, and simplify the technical requirements for future US human space efforts, especially in the wake of the planned 2010 retirement of the Space Shuttle.

Three major versions of the DIRECT proposal have been released; the latest, Version 3.0, was unveiled in May 2009. On 17 June 2009, the group presented its proposal at a public hearing of the Review of U.S. Human Space Flight Plans Committee, a panel reviewing US space efforts, in Washington, D.C.

Jupiter Launch Vehicle Family

DIRECT advocates developing a single, high-commonality family of "Jupiter" rockets, adapted closely from existing Space Shuttle systems. By comparison, NASA's Ares family would use two different highly modified versions of the Space Shuttle Solid Rocket Booster (SRB)and two different upper stages. as its first stage, for example. Supporters of DIRECT argue that NASA would be better served by developing and operating essentially a single mid-sized rocket system rather than two different rockets to perform crew launch (the smaller Ares I) and cargo launch (the larger Ares V).

Some envisioned Jupiter configurations, including crew and cargo variants

Each Jupiter launch vehicle would use a "common core stage" consisting of a tank structure based closely on the existing Space Shuttle External Tank with a pair of Solid Rocket Boosters SRBs mounted to its sides, as on the Space Shuttle. To reduce program cost and speed production, DIRECT advocates using the use of "standard" Shuttle SRBs, consisting of four propellant segments as opposed to the five-segment and five-and-one-half segment versions under development for Ares, in order to reduce program cost and schedule. Up to four Space Shuttle Main Engines normally carried in the "boattail" of from the Space Shuttle Orbiter would be attached to the bottom of the tank. In cargo-only Cargo versions would enclose the payload would be enclosed by a with a large aerodynamic fairing, while Crew versions would use would fly on Jupiters in the Orion spacecraft, currently under design by NASA, is currently designing topped by the Launch Abort System. As with Ares, the Shuttle Orbiter itself would be retired from flight.

Every Jupiter common core stage would be fitted for up to four SSMEs at the base. Smaller variants of DIRECT's Jupiter would use the same common core with fewer engines attached. would use this common core stage configuration as-is, typically with three main engines at the base. On Larger Jupiter vehicles, particularly those for missions to the Moon or beyond, would use all four SSMEs and include a cryogenic upper stage [link].an additional SSME would be mounted to the rocket's base, and a cryogenic upper stage would be added.

The DIRECT version 3.0 proposal, released in May 2009, centers around two primary configurations of the Jupiter: the Jupiter-130, which the group says would be capable of lifting over 60 metric tons to low Earth circular orbit, and the Jupiter-246, with an envisioned 90 metric-ton capability to the same a similar orbit.

Jupiter-130 (J-130) [if it's really a problem]

DIRECT proposes that its the smaller J-130 (the "130" standing for one cryogenic core stage with three SSME engines and zero upper stage engines) be developed first the first configuration of its configurations to be developed and flown with the goal of becoming operational shortly after near the time of Space Shuttle retirement. of the Space Shuttle. The J-130 , would consist of the Jupiter common core stage alone, fitted with three SSMEs and a large payload fairing on top. The "130" designation indicates one cryogenic stage, three cryogenic main engines, and zero upper-stage engines. The group asserts that the J-130 could lift 64,293 kg of payload to a 100 nmi (190 km), 29° inclined, circular_orbit above the Earth. In addition to the Orion spacecraft and crew, the J-130 would be designed to could accommodate cargo such as the Altair Lunar Surface Access Module as part of a two-launch lunar mission with a larger Jupiter-246 (described below).

Jupiter-246

The Jupiter-246 (J-246) would add an upper stage and one more main engine to the Jupiter-130 configuration. The J-246 would consist of two cryogenic stages, four core-stage SSME engines, and six RL-10B-2 engines in its cryogenic upper stage. DIRECT asserts that the J-246 could lift 91,670 kg of payload to a 130 nmi (240 km) 29° inclined, circular orbit. The RL-10 engine family, while not used on the Space Shuttle, was said to be chosen due to its near-term availability, long heritage of use on uncrewed rockets (including the Saturn I, Atlas V and Delta IV), and perceived readiness for full human-rating (certification for safe use in flying crews). The primary role for the Jupiter-246 would be to launch heavier cargo, although all Jupiters would be designed to be capable of launching crew.

Lunar Mission Architecture

As with the Ares I and Ares V, the DIRECT Team advocates the use of its Jupiter launchers for a variety of missions, including ISS crew rotation and cargo resupply, and the launch of heavy satellites and robotic exploration missions. However, a chief intent would be to use Jupiter to send astronauts to the Moon.

The baseline lunar mission approach for DIRECT Version 3.0 is similar to that for NASA's Constellation Program. Two launches would be performed for each lunar mission. The first Jupiter rocket would carry such payload as the planned Altair lunar lander, and/or the upper stage to be used as an Earth Departure Stage (EDS) to propel the mission out of low Earth orbit. The second rocket, to be launched shortly after the first, would bring the crewed Orion spacecraft to be mated with the payload from the first launch. The assembled Orion/Altair/EDS would leave Earth orbit for the Moon. The EDS would be expended, the spacecraft would enter lunar orbit, and the crew would descend to the Moon in the Altair while the Orion remained in lunar orbit.

Following surface exploration, the crew would fly a section of the Altair (the ascent stage) back to the Orion, discard the ascent stage, and put the Orion on a return trajectory to Earth. Before reentry, the Orion would discard its service module, and the crew would reenter and land in the Orion capsule.

In its various versions and literature, the DIRECT Team has postulated other mission architectures, for example using Lagrangian points in the Earth-Moon system as staging sites, as well as developing cryogenic propellant depots in low Earth orbit, to allow spacecraft to re-fuel in space and thus extend their range and capability. However, the primary DIRECT architecture intentionally matches that of NASA's.

Origins and History

1978 image of a Morton Thiokol-proposed In-Line Shuttle Derived Launch Vehicle. Note white tankage

DIRECT's Jupiter vehicle is a classic "inline" Shuttle-derived launch vehicle (SDLV) concept. This broad category of Shuttle adaptations, postulated since well before the first Shuttle launch, "discards" the winged Space Shuttle Orbiter, moves the liquid main engines to the bottom of the cryogenic tankage (typically proposed to be adapted from the Space Shuttle External Tank), and relocates the payload to above the tankage. (The other broad category of SDLV is the "side-mount", where the Orbiter is replaced directly by some form of payload carrier with engines.)

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.

NASA's Exploration Systems Architecture Study (ESAS) of 2005 included a very similar design, using three 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).

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 took 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 applied 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 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. NASA specified five RS-68 engines to make the Ares V Cargo LV. DIRECT's rocket would only need two engines. Additional performance and Initial Mass in Low Earth Orbit (IMLEO) could be provided by upgrading the main engines with Regenerative Cooling Nozzles to improve their efficiency; however, this upgrade was not required to accomplish the basic missions of both the crew and cargo programs.

The v1.0 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.

Criticism of v1.0

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 2,000 posts about DIRECT v1.0 appeared on the public forum at NASASpaceflight.com over a seven 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 Rocketdyne about the RS-68 Regen upgrades to prove his point. Later evidence from Rocketdyne confirmed that DIRECT v1.0's “overly-optimistic” RS-68 variant was in fact technically achievable, although it would 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 specified man-rating the standard performance RS-68 as used on existing Delta IV launchers and for the upper stage chose the lower of two specifications of J-2X engine which 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 Jupiter-120 and Jupiter-232.

The single-stage J-120 could still achieve low Earth orbit with two standard ablative RS-68 engines, while an extra RS-68 was required on the core stage of the heavier two-stage J-232. The Earth Departure Stage for J-232 now required two standard J-2X engines instead of one.

DIRECT v2.0 was further expanded with a 9-month study culminating in a 131-page exploration architecture study released on September 19, 2007 at the AIAA "Space 2007" Conference in Long Beach, CA. This 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. These capabilities included missions to Mars, Lagrangian point staging architecture options, and mission architectures for visiting Near-Earth object destinations..

v2.0 criticism and rebuttal

In June 2008, David King, director of NASA's Marshall Space Flight Center stated that NASA has considered DIRECT as well as many other rocket proposals, and that the Ares family was 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."

In July 2008, following statements of no special studies on DIRECT, NASA released some internal studies conducted in 2006 and 2007. Nearly a year later, on May 18th, 2009, the DIRECT team released a comprehensive rebuttal to the charges raised by NASA, concluding: "NASA’s October 2007 analysis of DIRECT, on the surface, appears to be a carefully executed analysis of the DIRECT architecture and its central launch vehicle, Jupiter. However, a closer examination of the document reveals significant flaws in the evaluation of DIRECT that set up a scenario where DIRECT would inevitably look inferior when compared to Ares. The errors are so numerous that the only conclusion possible is that this document cannot be used to properly assess the value of the DIRECT alternative."

DIRECT v3.0

On 29 May 2009, DIRECT spokesperson Stephen Metschan gave a presentation to the 28th Annual International Space Development Conference in Orlando, Florida entitled, "Direct 3.0: Landing Twice the Mass on the Moon at Half the Cost." In April of 2009, following NASA trade studies comparing use of the Space Shuttle Main Engine (SSME) to the originally planned RS-68 engine for Ares V, the DIRECT Team announced that future DIRECT proposals would recommend SSME as the core-stage engine. The engine change is due to concerns that the ablatively-cooled RS-68 would not survive the intense heat produced by the nearby exhaust plumes of the Space Shuttle SRBs. With Space Shuttle retirement nearing, DIRECT asserts that the higher cost of the regeneratively-cooled SSME will be offset by the time and money saved by not human-rating the RS-68, as that engine currently flies on uncrewed vehicles only. Similarly, for the upper stage, the DIRECT Team recommends using six RL-10B-2 engines as a proven, nearly human-rated alternative to NASA's J-2X engine, still in development.

On 17 June 2009, team member Stephen Metschan presented the DIRECT v3.0 concept to the Review of United States Human Space Flight Plans Committee chaired by Norman R. Augustine. The competing concepts presented included NASA's Ares I, commercial alternatives such as the United Launch Alliance Delta IV and SpaceX Falcon 9, and a new NASA "side-mount" Shuttle-derived launch vehicle concept presented by Space Shuttle Program Manager John Shannon.

Design Considerations

Expanded diagram of the DIRECT v2.0 Jupiter-120 configuration

DIRECT v2.0 performance examples

DIRECT v3.0 performance should be similar to the following DIRECT v2.0 examples: According to its proponents, initial DIRECT v2.0 performance to Low Earth Orbit (LEO) [specifically to 42x120nm, 28.5-degree inclination initial orbit] for this initial variant of the DIRECT Crew LV was conservatively expected to be at least 46,635kg (102,812lb), which was 250% of Ares I's 19,300kg (42,500lb) maximum performance. This meant 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 would have been 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 would have increased to at least 103,342kg (227,829lb).

Expanded diagram of the DIRECT v2.0 Jupiter-232 configuration

Gross performance for the two Ares I and Ares V launchers required for every Lunar mission was expected to be no more than 150,900kg (333,000lb). By comparison, two DIRECT v2.0 J-232 vehicles, one launching crew and spacecraft and the other launching mostly propellant, would have been capable of launching in excess of 220,000kg (485,000lb), including greater performance margin reserves.

DIRECT v3.0 uses existing engines

A major goal of DIRECT is to field the simplest rocket first. The recommended Jupiter-130 configuration specifies the standard 4-segment Solid Rocket Boosters (SRBs) from the Space Shuttle mounted to a tank structure as on the Space Shuttle. The Space Shuttle Main Engines attached to the bottom of the tank are identical to those of the Space Shuttle orbiter. To leave Low Earth Orbit, DIRECT calls for six RL-10B-2 engines on the J-246 Jupiter Upper Stage. All of these engines have extensive flight history or are already human-rated. By contrast, the Ares I cannot launch until both the 5-segment SRBs and J-2X upper stage engine are developed.

DIRECT can operate with existing engines, but could be modified to take advantage of developments such as the 5-segment SRB, the RL-60, or the J-2X.

Integrated Approach

Since design of the basic vehicle, more NASA engineers and managers have supported the concept and begun to consider the concept from a wider perspective. These professionals have contributed to a complete cost analysis comparison and 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.

These analyses show a clear difference in cost, schedule, maintenance, manufacturing and launch processing flow between the Ares and DIRECT approaches. DIRECT would re-use almost all of the existing facilities, whereas Ares I and Ares V each would require its own set of extensively overhauled or completely replaced facilities. This impacts almost every aspect of the operation from cost to design, development, testing, evaluation, implementation, schedule, risk mitigation, workforce retention and safety.

More specifically, 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.

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

Crew Safety

DIRECT envisions continued development and operation of NASA's Orion crewed spacecraft, including its launch abort system. In the event of an emergency, the Orion Launch Abort System would pull the crew capsule to safety, as it would on NASA's Ares I. The DIRECT Team asserts, however, that the Jupiter-130's greater lift capacity - 64 metric tons, versus 25 metric tons for Ares I - would enable the Orion to be designed with more crew safety capability than currently planned, at least from a launch-capacity standpoint.

For crewed flights to the International Space Station (ISS), DIRECT says the added lift capacity of the Jupiter would allow these missions to carry significant cargo in a separate module mounted below the Orion spacecraft. In this plan, once orbit was reached, the Orion would dock with this module and ferry it to the ISS. By comparison, Ares I would be capable of bringing only the Orion spacecraft to the ISS. DIRECT asserts that flying Orion and a separate payload module on a Jupiter would satisfy the safety concerns raised about flying crew separately from cargo following the 2003 Space Shuttle Columbia disaster, since the Orion capsule would still be able to separate from the launch vehicle and any cargo in the event of a launch abort.

Jupiter vs. Ares I

The DIRECT Team cites a number of particular features that it says would make a Jupiter-130 safer than the Ares I:

• The Jupiter design would re-use the proven method of Space Shuttle of attaching the SRBs to the tankage though an internal structural member. DIRECT says this would avoid the inducing of potentially severe vibration in the vehicle, resulting from a "thrust oscillation" effect endemic in large solid rockets. This effect has become a concern for the Ares I design..

• As with the Space Shuttle, the liquid main engines of a Jupiter-130 would be ignited on the ground and undergo a rapid checkout before the SRBs are ignited and the vehicle is launched. Start-sequence problems could be detected before committing to the launch, and the only vehicle staging event would be the burnout and separation of the SRBs. By comparison, the Ares I launch consists of the immediate ignition of its single SRB first stage, then requires a staging event and ignition at altitude of its cryogenic second stage. While staging is common launch vehicle practice, it introduces safety, risk and reliability concerns, particularly on crewed flights. (The larger J-246, with its upper stage, would typically include this risk.)

• The DIRECT Team asserts that the Jupiter-130 and -246, with their multiple main engines, would be capable of reaching orbit even in the event of an engine shutdown.

• In the Jupiter concept, the crewed Orion spacecraft would be supported by a large aerodynamic fairing. This arrangement would place the Orion at least 10 meters (33ft) further away from propellant-filled stages than it would be on an Ares I. DIRECT asserts this would provide a valuable additional "buffer space" between an exploding vehicle and the crew.

• The envisioned lift capacity of the Jupiter-130 could allow protective hardware to be mounted inside the payload fairing, below the Orion spacecraft. DIRECT has postulated such options as mounting a lightweight shield made from Boron carbide and Kevlar between the spacecraft and the stages below to help protect the crew from shrapnel and other debris from a vehicle explosion.

Jupiter vs. Ares V

The current baseline configuration of the Ares V heavy-lift cargo rocket employs six RS-68B main engines and two "stretched" 5.5segment SRBs. According to NASA, this vehicle design 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 1,000 (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.

The DIRECT Team asserts that, 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 now superseded DIRECT v2.0 Jupiter-232, was expected to comfortably exceed these targets with an LOC of 1 in 1,162. DIRECT's advocates say that, if the DIRECT v3.0 vehicles have similar safety margins, the DIRECT system could offer considerable mission flexibility. Lunar missions could be flown with a pair of powerful two-stage Jupiters instead of one single-stage crew vehicle and one two-stage cargo vehicle.

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 canceled, 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. Former 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. 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. Three years later, the current NASA schedule has slipped by more than 4 years with a 65% confidence that the very first flight of Orion 2 (the first manned flight with the Orion spacecraft) will occur 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 the delays 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 the slippage.

Comparatively, to fly the Orion sooner, DIRECT proposes to reuse the existing 4-segment Space Shuttle Solid Rocket Booster and Space Shuttle Main Engine which are already fully qualified for human use and reuse existing manufacturing to build a modified variant of the existing Space Shuttle External Tank. Only moderate modifications are required at Kennedy Space Center to enable launches. All DIRECT variants share a common footprint which allows flexibility in final assembly and choice of launch site.

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 critical activity of Ares I development 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 fix the Ares I to stop 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-130 vehicle, by not requiring the 5-segment SRB at all and by providing more than 60 t of lift performance allowing the Orion design to be solidified today and go straight on to PDR unhindered.

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 reused to speed development work of the other elements, Orion, Jupiter-130, 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-130 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-130.

An additional aspect of the DIRECT proposal is to utilize some of the funds 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-130. The 20 t of extra payload capability of the Jupiter-130 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 Modules 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.

Missions

Because DIRECT relies heavily on technology derived from the Space Shuttle, much of the planned missions in Project Constellation will move significantly earlier in schedule. The first crewed CEV will fly in December 2012. The first ISS rotation will take place in September 2013. The first crewed Lunar flyby will take place in December 2013. A possible fifth Hubble Space Telescope service mission can fly in December 2014. The first manned Lunar mission can take place on December 2017 and the first manned Mars mission can take place in 2031.

Advantages and disadvantages

Proponents assert that the DIRECT proposal would enable NASA to fulfill the mandate of the Vision for Space Exploration sooner and more safely than the planned Ares I and Ares V, at a lower cost and with far less programmatic risk due to the "simpler" approach of minimizing new development. Unlike the budget plans for Ares I and Ares V, advocates say DIRECT would allow NASA provide sufficient budget to do more continue funding programs beyond launch vehicle development and operation, including extending its participation in the International Space Station beyond 2016, while being better able to withstand the unpredictability of future annual congressional/administration budget allocations. (In a play on Alliant Techsystems' tagline that Ares would be "Simple, Safe and Soon", proponents have quipped that DIRECT would be "Simpler, Safer and Sooner.")

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-130 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.

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
• NASASpaceFlight.com
  • DIRECT v1.0 discussion (now locked at 131 pages)
  • DIRECT v2.0 discussion (now locked at 250 pages)
  • DIRECT v2.0 Thread 2 discussion (now locked at 300 pages)
  • DIRECT v2.0 Thread 3 discussion (now locked at 250 pages)
  • DIRECT v2.0 Thread 4 discussion (13 pages)
  • DIRECT v3.0 discussion
• 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" June 22, 2008 Retrieved on 2009-06-04.
• International Space Development Conference presentation in PPS
• Saving America's Space Program - The Space Review Aug 11, 2008
• Article about Direct on Popular Mechanics
• New Scientist - In search of NASA's next rocket Illustration with DIRECT pros and cons
• Revisiting a DIRECT approach, Horizons, American Institute of Aeronautics and Astronautics - Houston Section, 34,2 (Summer 2009), 8-11.