DIRECT
Encyclopedia
DIRECT is a proposed alternative heavy lift launch vehicle
architecture supporting NASA
's Vision for Space Exploration
, which would replace the space agency's planned Ares I
and Ares V
rockets. The original family of Shuttle-Derived Launch Vehicle
s are named "Jupiter", while the more ambitious "Project 2", launched in 2011 consists of the Leviathan heavy launcher vehicle, the Olympia orbital support station, the Galleon heavy cargo ship, the Argo and the Helios space stations and the Artemis crew cargo ship.
DIRECT is advocated by a group of space enthusiasts that asserts it represents a broader team of dozens of NASA and space industry engineers who actively work on the proposal on an anonymous, voluntary basis in their spare time. , 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. A small number of non-NASA members of the team publicly represent the group.
The project name "DIRECT" refers to a philosophy of maximizing the re-use of hardware and facilities already in place for the Space Shuttle program
(STS), hence a "direct" transition. The DIRECT Team asserts that using this approach to develop and operate a family of high-commonality rockets would reduce costs and the gap between retirement of the Space Shuttle and the first launch of Orion, shorten schedules, and simplify technical requirements for future US human space efforts.
Three major versions of the DIRECT proposal have been released with the latest, Version 3.0, having been 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.
With the October 11th signing of the NASA Authorization Act of 2010
(S. 3729) by President Obama mandating work on the Space Launch System
Heavy Lift Launch Vehicle
, the DIRECT Team has declared success of their effort. They have since announced the formation of a new space technology company: C-Star Aerospace, LLC.
DIRECT advocates developing a single, high-commonality family of rockets named Jupiter, adapted closely from existing Space Shuttle systems. 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 standard four-segment Solid Rocket Boosters
(SRBs) mounted at the sides as on the Space Shuttle
. Up to four Space Shuttle Main Engine
s (SSMEs) from the Space Shuttle Orbiter
would be attached to the bottom of the External Tank. The engines would be deorbited along with the expended tank to burn up in the Earth's atmosphere.
For flights lifting payloads massing 70 Tonne
s or less, the Jupiter would fly with no upper stage and utilize only three SSMEs. This configuration is designated the Jupiter-130, indicating one cryogenic stage to reach orbital insertion, three SSMEs powering this common core stage and no engines on the upper stage (because there is no upper stage).
For heavier payloads a proposed Jupiter Upper Stage (JUS) would be added atop the tank structure and a fourth SSME would be mounted on the base of the common core stage. This configuration is designated the Jupiter-246, indicating two cryogenic stages to reach orbital insertion, four SSMEs powering the Common core stage and six RL-10
cryogenic engines powering the JUS.
For extra-planetary expeditions, the JUS would serve in a role similar to the Earth Departure Stage
planned for Ares V. DIRECT have specified existing components for their launch vehicles, but contend that they could incorporate improvements such as the more powerful five-segment SRB and J-2X upper stage engine currently under development for the Constellation Program should they become available.
Crews would be carried atop the launch vehicle in NASA's planned Orion Crew Exploration Vehicle
, itself topped by the planned Launch Abort System
. Cargo, whether carried behind the Orion spacecraft or alone on a cargo-only launch would be enclosed by a payload fairing
.
Many configurations of Jupiter are possible, but the DIRECT version 3.0 proposal, released in May 2009, recommends two: the Jupiter-130 and Jupiter-246, with claimed lift capacities exceeding 70 and 110 tonne
s, respectively, to low Earth orbit
.
The extra payload capability of the Jupiter-130 would allow 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 has suggested a number of extra missions which would be enabled by Jupiter in their proposal, including:
The DIRECT team asserts that these additional new missions can be planned and funded due to development cost savings with the Jupiter rocket family compared to the current NASA baseline. The proposed new missions and payloads could provide useful employment for many people currently working in the Space Shuttle
Program, which is scheduled to end in 2011.
along with NASA's planned Altair Lunar Surface Access Module lunar lander. Another Jupiter-246 would be launched, its Jupiter Upper Stage (JUS) fully fueled with no payload. This particular JUS would serve as the Earth Departure Stage. The two upper stages would meet in low Earth orbit and the lunar spacecraft would transfer from the spent JUS to the fresh JUS. The assembled Orion/Altair/JUS would leave Earth orbit for the Moon. The JUS would be expended on reaching the moon. After this the spacecraft would enter lunar orbit, and the entire 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 and Orion capsule would reenter Earth's atmosphere and land with parachutes deployed.
DIRECT calculates that the two Jupiter-246s will be able to send 80.7 t of mass through trans-lunar injection. This compares favourably with an Ares I / Ares V dual launch, as of September 2008, projected to be capable of 71.1 t.
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 depot
s 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.
DIRECT's Jupiter vehicle is an "in-line" Space Shuttle-derived launch vehicle. This broad category of Shuttle adaptations, postulated since before the first Shuttle launch, removes the winged Space Shuttle Orbiter
, moves the liquid main engines to the bottom of the cryogenic tankage (typically proposed to be adapted from the Shuttle External Tank
), and relocates the payload to above the tankage.
The first official study of the concept 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 alternatives for launching unmanned cargo and would have potentially allowed a re-started lunar 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.
DIRECT has a resemblance 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 Solid Rocket Boosters and modified External Tank, but instead of the reusable Space Shuttle Main Engine, specifed four of the proposed disposable, less expensive Space Transportation Main Engines. The United States Congress did not appropriate funding for the development. A great deal of reference material exists in the public domain regarding NLS.
NASA
's Exploration Systems Architecture Study
(ESAS) of 2005 included a similar design to the DIRECT proposal using three Space Shuttle Main Engine
s (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's re-exploration of the SDLV idea began in 2006 in frustration with the high cost and delays of Ares I and worries that any similar issues with the giant Ares V might put the whole Constellation Program in jeopardy. An additional goal was to maintain American ability to launch crews to space with as short a gap as possible after the planned retirement of Shuttle.
engineers and managers working in their free time, and a small group of engineers and non-engineers outside of NASA. 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 the Ares V 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 as the core engines for Ares V
. The DIRECT proposal specified that its core should include two RS-68 engines. Additional performance for carrying payloads to Low Earth Orbit would be provided by upgrading the main engines with Regenerative Cooling Nozzles to improve their efficiency.
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 Constellation program.
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 as evidence for his point.
On May 10, 2007, a revised DIRECT proposal was released. To address criticism of relying on engine studies rather than working engines, DIRECT v2.0 specified human-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 is 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.
According to the proposal, the single-stage Jupiter-120 could 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 Jupiter-232. The Earth Departure Stage for Jupiter-232 now required two standard J-2X engines instead of one.
The DIRECT Team produced a 131-page DIRECT v2.0 exploration architecture study that was released on September 19, 2007 at the AIAA "Space 2007" Conference in Long Beach, CA. According to the group, this paper was created within a 9-month study. The paper provided detail on how the launch vehicles would be one component of a wider-reaching architecture for enabling the US to maintain the ISS
, fly lunar missions, and provide additional capabilities for the NASA human spaceflight program. These capabilities included missions to Mars, Lagrangian point
staging architecture options, and mission architectures for visiting Near-Earth object
destinations.
, 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 NASA statements of no special studies on DIRECT, the space agency released some internal studies conducted in 2006 and 2007. Nearly a year later, on May 18, 2009, the DIRECT team released a 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."
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 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 was 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. 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. Similarly, for the upper stage, the DIRECT Team recommends using six of the flight-proven RL10B-2 engine.
In May 2009 the Office of Science and Technology Policy
announced the Review of United States Human Space Flight Plans Committee
to be chaired by Norman R. Augustine
. On 17 June 2009, team member Stephen Metschan presented the DIRECT v3.0 concept to the Committee, which was formed to offer independent advice to the incoming Obama Administration
. The Committee's final report did not directly compare DIRECT to the Constellation Program, but did offer budget, schedule, and mission combinations where a shuttle-derived launch vehicle could be used.
On 19 January 2010, amid rumors that NASA would propose a DIRECT-like inline launch vehicle, the DIRECT team made a presentation to NASA Associate Administrator for Exploration Systems Mission Directorate, Douglas Cooke, and NASA Associate Administrator for Space Operations, William H. Gerstenmaier
, in a meeting convened by NASA Administrator Charles F. Bolden, Jr.
and the various launch-processing facilities currently at the Kennedy Space Center
. DIRECT proposes to re-use nearly all of the existing facilities with minimal modifications in contrast to the Ares I
and Ares V
rockets which will require extensive modifications and replacements over existing facilities.
The DIRECT's core stage would remain at the existing 8.41 m (27.6 ft) diameter of the Shuttle's External Tank compared to 10.06 m (33 ft) for Ares V. The DIRECT team claims that by not increasing the core stage diameter the existing External Tank manufacturing tooling 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 Platform
s and Crawler-Transporter
s, and parts of the structure of the existing Fixed Service Structure and Flame Trenches at Launch Complex 39 could be used without major modifications.
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, indicating that the Ares V
will be more expensive to develop than the Ares I
.
The disadvantage of one launcher for two very different roles was pointed out by David King
, director of NASA's Marshall Space Flight Center
. "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."
has incurred several delays since the inception of the new lunar program. The original intent in the Exploration Systems Architecture Study
(ESAS) Report was to have a crewed flight as early as mid-2011 after the Space Shuttle retirement in 2010. The official current NASA schedule has a 65% confidence that the first manned flight of Ares I with Orion (Orion 2
) will occur in March 2015.
The critical
activity of Ares I
development is currently the schedule for the J-2X upper stage engine and the five-segment version of the SRB
. Engineers are concerned about thrust oscillation and Orion-Ares I integration. In 2008, Lockheed Martin requested that NASA redesign Ares I
in order to end integration risks with the Orion crew capsule. The combined test results from the Ares I-X launch and the Ares I static test firing now indicate that thrust oscillation is not a critical issue, according to program engineers.
in order to fly the first Orion is directly responsible for the delays in schedule and the comparatively high development costs. All-new manufacturing at the Michoud Assembly Facility
and launch facilities at Kennedy Space Center
are also required for Ares I. In contrast, DIRECT proposes to reuse the existing 4-segment fully human rated Space Shuttle Solid Rocket Booster
and Space Shuttle Main Engine
. DIRECT also proposes reuse of existing manufacturing to build a modified variant of the existing Space Shuttle External Tank
. Only moderate modifications would be required at Kennedy Space Center
to enable launches. DIRECT’s proposal for a single launch vehicle removes the program risks associated with the possible cancellation of the Ares V launcher due to budgetary constraints.
DIRECT asserts its Jupiter launchers avoid the delays of Ares I by not requiring the J-2X on the first-generation Jupiter-130 vehicle, by not requiring the five-segment SRB
and by providing more than 60 t of lift performance that would ameliorate weight issues on the Orion design.
DIRECT also claims that money would be saved by avoiding a parallel development of the Ares V
booster, since the Jupiter family would represent a single rocket family program. The group suggests that the money saved on Ares V be reused to speed development work of such other elements as the Orion, the 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 trimmed substantially, allowing full operational capability of an Orion/Jupiter-130 system to perform 6-person crew rotations and cargo deliveries to the ISS
by 2013.
sooner and more safely than the planned Ares I and Ares V, at a lower cost and with less programmatic risk due to a simpler approach which decreases new development efforts. Advocates say the DIRECT proposal would allow NASA to provide sufficient money to continue funding programs beyond launch vehicle development and operation, including extending its participation in the International Space Station
, which is scheduled to end in 2016 as of 2009. The DIRECT proposal also suggests that NASA uses costs savings from the DIRECT proposal to accelerate the VSE's
schedule for returning to the Moon and to potentially fly other missions such as servicing missions to the Hubble Space Telescope.
In contrast to these claims, NASA senior manager for the STS program, John Shannon has stated that he thinks the DIRECT proposal underestimates the costs for the Jupiter rocket family.
series of upper stages, DIRECT specifically cites new materials, new welding techniques, and a common bulkhead separating the Liquid Oxygen and Liquid Hydrogen tanks as sufficient to account for the low stage mass. Bernard Kutter of United Launch Alliance
described the even more radical DIRECT v2.0 JUS design as, "...very reasonable. I’d even call it conservative."
completed in 2007 only requires a 125mt+ launch vehicle with a 10m+ diameter shroud for a Mars mission with 6 separate Ares V launches. The Jupiter rocket fulfills the requirements of the Design Reference Mission with only a very narrow shortfall in payload to LEO, while fulfilling the volume requirements.
The Jupiter rockets are shorter in height than the Ares V, permitting very long payload fairings and thus greater total internal volume than possible with the taller Ares V which quickly encounters restraints due to height limitations within the Vehicle Assembly Building
at Kennedy Space Center
.
Heavy Lift Launch Vehicle
A Heavy Lift Launch Vehicle, or HLLV, is a launch vehicle capable of lifting more mass into Low Earth Orbit than Medium Lift or Mid-Heavy Lift Launch Vehicles.There is no universally accepted capability requirements for heavy-lift launch vehicles....
architecture supporting NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
's Vision for Space Exploration
Vision for Space Exploration
The Vision for Space Exploration is the United States space policy which was announced on January 14, 2004 by President George W. Bush. It is seen as a response to the Space Shuttle Columbia disaster, the state of human spaceflight at NASA, and a way to regain public enthusiasm for space...
, which would replace the space agency's planned Ares I
Ares I
Ares I was the crew launch vehicle that was being developed by NASA as part of the Constellation Program. The name "Ares" refers to the Greek deity Ares, who is identified with the Roman god Mars...
and Ares V
Ares V
The Ares V was the planned cargo launch component of the Constellation program, which was to have replaced the Space Shuttle after its retirement in 2011. Ares V was also planned to carry supplies for a human presence on Mars...
rockets. The original family of Shuttle-Derived Launch Vehicle
Shuttle-Derived Launch Vehicle
Shuttle-Derived Launch Vehicle, or simply Shuttle-Derived Vehicle , is a term describing one of a wide array of concepts that have been developed for creating space launch vehicles from the components, technology and/or infrastructure of the Space Shuttle program. SDVs have also been part of...
s are named "Jupiter", while the more ambitious "Project 2", launched in 2011 consists of the Leviathan heavy launcher vehicle, the Olympia orbital support station, the Galleon heavy cargo ship, the Argo and the Helios space stations and the Artemis crew cargo ship.
DIRECT is advocated by a group of space enthusiasts that asserts it represents a broader team of dozens of NASA and space industry engineers who actively work on the proposal on an anonymous, voluntary basis in their spare time. , 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. A small number of non-NASA members of the team publicly represent the group.
The project name "DIRECT" refers to a philosophy of maximizing the re-use of hardware and facilities already in place for the Space Shuttle program
Space Shuttle program
NASA's Space Shuttle program, officially called Space Transportation System , was the United States government's manned launch vehicle program from 1981 to 2011...
(STS), hence a "direct" transition. The DIRECT Team asserts that using this approach to develop and operate a family of high-commonality rockets would reduce costs and the gap between retirement of the Space Shuttle and the first launch of Orion, shorten schedules, and simplify technical requirements for future US human space efforts.
Three major versions of the DIRECT proposal have been released with the latest, Version 3.0, having been 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.
With the October 11th signing of the NASA Authorization Act of 2010
NASA Authorization Act of 2010
The NASA Authorization Act of 2010 is a U.S. law which authorizes NASA appropriations for fiscal years 2011–2013 with the same top-line budget values as requested by President of the United States Barack Obama...
(S. 3729) by President Obama mandating work on the Space Launch System
Space Launch System
The Space Launch System, or SLS, is a Space Shuttle-derived heavy launch vehicle being designed by NASA, following the cancellation of the Constellation Program, to replace the retired Space Shuttle. The NASA Authorization Act of 2010 envisions the transformation of the Ares I and Ares V vehicle...
Heavy Lift Launch Vehicle
Heavy Lift Launch Vehicle
A Heavy Lift Launch Vehicle, or HLLV, is a launch vehicle capable of lifting more mass into Low Earth Orbit than Medium Lift or Mid-Heavy Lift Launch Vehicles.There is no universally accepted capability requirements for heavy-lift launch vehicles....
, the DIRECT Team has declared success of their effort. They have since announced the formation of a new space technology company: C-Star Aerospace, LLC.
Jupiter launch vehicle family
Space Shuttle Solid Rocket Booster
The Space Shuttle Solid Rocket Boosters were the pair of large solid rockets used by the United States' NASA Space Shuttle during the first two minutes of powered flight. Together they provided about 83% of liftoff thrust for the Space Shuttle. They were located on either side of the rusty or...
(SRBs) mounted at the sides as on the Space Shuttle
Space Shuttle
The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...
. Up to four Space Shuttle Main Engine
Space Shuttle main engine
The RS-25, otherwise known as the Space Shuttle Main Engine , is a reusable liquid-fuel rocket engine built by Pratt & Whitney Rocketdyne for the Space Shuttle, running on liquid hydrogen and oxygen. Each Space Shuttle was propelled by three SSMEs mated to one powerhead...
s (SSMEs) from the Space Shuttle Orbiter
Space Shuttle Orbiter
The Space Shuttle orbiter was the orbital spacecraft of the Space Shuttle program operated by NASA, the space agency of the United States. The orbiter was a reusable winged "space-plane", a mixture of rockets, spacecraft, and aircraft...
would be attached to the bottom of the External Tank. The engines would be deorbited along with the expended tank to burn up in the Earth's atmosphere.
For flights lifting payloads massing 70 Tonne
Tonne
The tonne, known as the metric ton in the US , often put pleonastically as "metric tonne" to avoid confusion with ton, is a metric system unit of mass equal to 1000 kilograms. The tonne is not an International System of Units unit, but is accepted for use with the SI...
s or less, the Jupiter would fly with no upper stage and utilize only three SSMEs. This configuration is designated the Jupiter-130, indicating one cryogenic stage to reach orbital insertion, three SSMEs powering this common core stage and no engines on the upper stage (because there is no upper stage).
For heavier payloads a proposed Jupiter Upper Stage (JUS) would be added atop the tank structure and a fourth SSME would be mounted on the base of the common core stage. This configuration is designated the Jupiter-246, indicating two cryogenic stages to reach orbital insertion, four SSMEs powering the Common core stage and six RL-10
RL-10
The RL10 was USA's first liquid hydrogen fueled rocket engine. An updated version is used in several current launch vehicles. Six RL10 engines were used in the S-IV second stage of the Saturn I rocket. One or two RL10 engines are used in the Centaur upper stages of Atlas and Titan rockets...
cryogenic engines powering the JUS.
For extra-planetary expeditions, the JUS would serve in a role similar to the Earth Departure Stage
Earth Departure Stage
The Ares V Earth Departure Stage was a rocket stage which NASA planned to design at its Marshall Space Flight Center in Huntsville, Alabama as part of Project Constellation...
planned for Ares V. DIRECT have specified existing components for their launch vehicles, but contend that they could incorporate improvements such as the more powerful five-segment SRB and J-2X upper stage engine currently under development for the Constellation Program should they become available.
Crews would be carried atop the launch vehicle in NASA's planned Orion Crew Exploration Vehicle
Orion (spacecraft)
Orion is a spacecraft designed by Lockheed Martin for NASA, the space agency of the United States. Orion development began in 2005 as part of the Constellation program, where Orion would fulfill the function of a Crew Exploration Vehicle....
, itself topped by the planned Launch Abort System
Launch escape system
A Launch Escape System is a top-mounted rocket connected to the crew module of a crewed spacecraft and used to quickly separate the crew module from the rest of the rocket in case of emergency. Since the escape rockets are above the crew module, an LES typically uses separate nozzles which are...
. Cargo, whether carried behind the Orion spacecraft or alone on a cargo-only launch would be enclosed by a payload fairing
Payload fairing
Payload fairing is one of the main components of a launch vehicle. The fairing protects the payload during the ascent against the impact of the atmosphere . More recently, an additional function is to maintain the cleanroom environment for precision instruments.Outside the atmosphere the fairing is...
.
Many configurations of Jupiter are possible, but the DIRECT version 3.0 proposal, released in May 2009, recommends two: the Jupiter-130 and Jupiter-246, with claimed lift capacities exceeding 70 and 110 tonne
Tonne
The tonne, known as the metric ton in the US , often put pleonastically as "metric tonne" to avoid confusion with ton, is a metric system unit of mass equal to 1000 kilograms. The tonne is not an International System of Units unit, but is accepted for use with the SI...
s, respectively, to low Earth orbit
Low Earth orbit
A low Earth orbit is generally defined as an orbit within the locus extending from the Earth’s surface up to an altitude of 2,000 km...
.
Low Earth Orbit and Unmanned Scientific Missions
Ares I
Ares I was the crew launch vehicle that was being developed by NASA as part of the Constellation Program. The name "Ares" refers to the Greek deity Ares, who is identified with the Roman god Mars...
. The DIRECT Team has suggested a number of extra missions which would be enabled by Jupiter in their proposal, including:
- New ISS resupply missions with the three ESAEuropean Space AgencyThe European Space Agency , established in 1975, is an intergovernmental organisation dedicated to the exploration of space, currently with 18 member states...
/ASIItalian Space AgencyThe Italian Space Agency is a government agency established in 1988 to fund, regulate and coordinate space exploration activities in Italy...
-built Multi-Purpose Logistics ModuleMulti-Purpose Logistics ModuleA Multi-Purpose Logistics Module is a large pressurized container used on Space Shuttle missions to transfer cargo to and from the International Space Station . An MPLM was carried in the cargo bay of a Shuttle and berthed to the Unity or Harmony modules on the ISS. From there, supplies were...
s - Performing more Hubble Space TelescopeHubble Space TelescopeThe Hubble Space Telescope is a space telescope that was carried into orbit by a Space Shuttle in 1990 and remains in operation. A 2.4 meter aperture telescope in low Earth orbit, Hubble's four main instruments observe in the near ultraviolet, visible, and near infrared...
Servicing Missions with Orion crews - Launching massive new space telescopes over 8 meters in diameter (more than 3 times the diameter of HubbleHubble Space TelescopeThe Hubble Space Telescope is a space telescope that was carried into orbit by a Space Shuttle in 1990 and remains in operation. A 2.4 meter aperture telescope in low Earth orbit, Hubble's four main instruments observe in the near ultraviolet, visible, and near infrared...
) - Perform a 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
The DIRECT team asserts that these additional new missions can be planned and funded due to development cost savings with the Jupiter rocket family compared to the current NASA baseline. The proposed new missions and payloads could provide useful employment for many people currently working in the Space Shuttle
Space Shuttle
The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...
Program, which is scheduled to end in 2011.
Lunar Mission Architecture
As with NASA's Constellation Program baseline, two launches would be performed for a DIRECT lunar mission. One Jupiter-246 rocket would carry the crew in NASA's planned Orion Crew Exploration VehicleOrion (spacecraft)
Orion is a spacecraft designed by Lockheed Martin for NASA, the space agency of the United States. Orion development began in 2005 as part of the Constellation program, where Orion would fulfill the function of a Crew Exploration Vehicle....
along with NASA's planned Altair Lunar Surface Access Module lunar lander. Another Jupiter-246 would be launched, its Jupiter Upper Stage (JUS) fully fueled with no payload. This particular JUS would serve as the Earth Departure Stage. The two upper stages would meet in low Earth orbit and the lunar spacecraft would transfer from the spent JUS to the fresh JUS. The assembled Orion/Altair/JUS would leave Earth orbit for the Moon. The JUS would be expended on reaching the moon. After this the spacecraft would enter lunar orbit, and the entire 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 and Orion capsule would reenter Earth's atmosphere and land with parachutes deployed.
DIRECT calculates that the two Jupiter-246s will be able to send 80.7 t of mass through trans-lunar injection. This compares favourably with an Ares I / Ares V dual launch, as of September 2008, projected to be capable of 71.1 t.
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 depot
Propellant depot
An orbital propellant depot is a cache of propellant that is placed on an orbit about the Earth or another body to allow spacecraft to be fuelled in space. Launching a spacecraft separately from some of its propellant enables missions with more massive payloads...
s 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
Space Shuttle Orbiter
The Space Shuttle orbiter was the orbital spacecraft of the Space Shuttle program operated by NASA, the space agency of the United States. The orbiter was a reusable winged "space-plane", a mixture of rockets, spacecraft, and aircraft...
, moves the liquid main engines to the bottom of the cryogenic tankage (typically proposed to be adapted from the Shuttle External Tank
Space Shuttle external tank
A Space Shuttle External Tank is the component of the Space Shuttle launch vehicle that contains the liquid hydrogen fuel and liquid oxygen oxidizer. During lift-off and ascent it supplies the fuel and oxidizer under pressure to the three Space Shuttle Main Engines in the orbiter...
), and relocates the payload to above the tankage.
The first official study of the concept was conducted in 1986 by NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
's Marshall Space Flight Center
Marshall Space Flight Center
The George C. Marshall Space Flight Center is the U.S. government's civilian rocketry and spacecraft propulsion research center. The largest center of NASA, MSFC's first mission was developing the Saturn launch vehicles for the Apollo moon program...
in the aftermath of the Space Shuttle Challenger disaster
Space Shuttle Challenger disaster
The Space Shuttle Challenger disaster occurred on January 28, 1986, when Space Shuttle Challenger broke apart 73 seconds into its flight, leading to the deaths of its seven crew members. The spacecraft disintegrated over the Atlantic Ocean, off the coast of central Florida at 11:38 am EST...
. It was promoted as one of the alternatives for launching unmanned cargo and would have potentially allowed a re-started lunar program as well. There were, however, no funds available to NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
for building any new vehicles while the Space Shuttle
Space Shuttle
The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...
Program continued. The idea was shelved and NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
concentrated on fixing and operating the Space Shuttle
Space Shuttle
The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...
instead.
DIRECT has a resemblance to the 1991 National Launch System
National Launch System
The National Launch System was a study authorized in 1991 by President George H. W. Bush to outline alternatives to the Space Shuttle for access to Earth Orbit. Shortly thereafter, NASA asked Lockheed Missiles and Space, McDonnell Douglas, and TRW, to perform a ten-month study...
effort. Proposed jointly by NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
and the Department of Defense
United States Department of Defense
The United States Department of Defense is the U.S...
as an alternative to the Titan IV
Titan IV
The Titan IV family of space boosters were used by the U.S. Air Force. They were launched from Cape Canaveral Air Force Station, Florida, and Vandenberg Air Force Base, California. At the time of its introduction, the Titan IV was the "largest unmanned space booster used by the Air Force."The...
, the design was based on the same Solid Rocket Boosters and modified External Tank, but instead of the reusable Space Shuttle Main Engine, specifed four of the proposed disposable, less expensive Space Transportation Main Engines. The United States Congress did not appropriate funding for the development. A great deal of reference material exists in the public domain regarding NLS.
NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
's Exploration Systems Architecture Study
Exploration Systems Architecture Study
The Exploration Systems Architecture Study is the official title of a large-scale, system level study released by the National Aeronautics and Space Administration in November 2005 in response to American president George W...
(ESAS) of 2005 included a similar design to the DIRECT proposal using three Space Shuttle Main Engine
Space Shuttle main engine
The RS-25, otherwise known as the Space Shuttle Main Engine , is a reusable liquid-fuel rocket engine built by Pratt & Whitney Rocketdyne for the Space Shuttle, running on liquid hydrogen and oxygen. Each Space Shuttle was propelled by three SSMEs mated to one powerhead...
s (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
Earth Departure Stage
The Ares V Earth Departure Stage was a rocket stage which NASA planned to design at its Marshall Space Flight Center in Huntsville, Alabama as part of Project Constellation...
(EDS).
DIRECT's re-exploration of the SDLV idea began in 2006 in frustration with the high cost and delays of Ares I and worries that any similar issues with the giant Ares V might put the whole Constellation Program in jeopardy. An additional goal was to maintain American ability to launch crews to space with as short a gap as possible after the planned retirement of Shuttle.
DIRECT v1.0
According to the DIRECT team, the first version of the DIRECT proposal was the product of a three-month study produced by more than a dozen NASANASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
engineers and managers working in their free time, and a small group of engineers and non-engineers outside of NASA. DIRECT took the final ESAS
Exploration Systems Architecture Study
The Exploration Systems Architecture Study is the official title of a large-scale, system level study released by the National Aeronautics and Space Administration in November 2005 in response to American president George W...
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
Space Shuttle main engine
The RS-25, otherwise known as the Space Shuttle Main Engine , is a reusable liquid-fuel rocket engine built by Pratt & Whitney Rocketdyne for the Space Shuttle, running on liquid hydrogen and oxygen. Each Space Shuttle was propelled by three SSMEs mated to one powerhead...
on the Ares V 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 as the core engines for Ares V
Ares V
The Ares V was the planned cargo launch component of the Constellation program, which was to have replaced the Space Shuttle after its retirement in 2011. Ares V was also planned to carry supplies for a human presence on Mars...
. The DIRECT proposal specified that its core should include two RS-68 engines. Additional performance for carrying payloads to Low Earth Orbit would be provided by upgrading the main engines with Regenerative Cooling Nozzles to improve their efficiency.
The v1.0 proposal was submitted on October 25, 2006 to NASA's Administrator, Michael D. Griffin
Michael D. Griffin
Michael Douglas Griffin is an American physicist and aerospace engineer. From April 13, 2005 to January 20, 2009 he served as Administrator of NASA, the space agency of the United States...
, and a wide range of industry, political and advocacy groups involved in the Constellation program.
Criticism of v1.0
In late 2006, head of the ESASExploration Systems Architecture Study
The Exploration Systems Architecture Study is the official title of a large-scale, system level study released by the National Aeronautics and Space Administration in November 2005 in response to American president George W...
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
Rocketdyne
Rocketdyne was a Rocket engine design and production company headquartered in Canoga Park, California, United States. The company was related to North American Aviation for most of its history. NAA merged with Rockwell International, which was then bought by Boeing in December, 1996...
about the RS-68 Regen upgrades as evidence for his point.
DIRECT v2.0
According to the proposal, the single-stage Jupiter-120 could 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 Jupiter-232. The Earth Departure Stage for Jupiter-232 now required two standard J-2X engines instead of one.
The DIRECT Team produced a 131-page DIRECT v2.0 exploration architecture study that was released on September 19, 2007 at the AIAA "Space 2007" Conference in Long Beach, CA. According to the group, this paper was created within a 9-month study. The paper provided detail on how the launch vehicles would be one component of a wider-reaching architecture for enabling the US to maintain the ISS
International Space Station
The International Space Station is a habitable, artificial satellite in low Earth orbit. The ISS follows the Salyut, Almaz, Cosmos, Skylab, and Mir space stations, as the 11th space station launched, not including the Genesis I and II prototypes...
, fly lunar missions, and provide additional capabilities for the NASA human spaceflight program. These capabilities included missions to Mars, Lagrangian point
Lagrangian point
The Lagrangian points are the five positions in an orbital configuration where a small object affected only by gravity can theoretically be stationary relative to two larger objects...
staging architecture options, and mission architectures for visiting Near-Earth object
Near-Earth object
A near-Earth object is a Solar System object whose orbit brings it into close proximity with the Earth. All NEOs have a perihelion distance less than 1.3 AU. They include a few thousand near-Earth asteroids , near-Earth comets, a number of solar-orbiting spacecraft, and meteoroids large enough to...
destinations.
Criticism and Rebuttal of v2.0
In June 2008, David KingDavid A. King
David A. King was the tenth Director of the NASA Marshall Space Flight Center located in Huntsville, Alabama. He was appointed to the position on June 15, 2003. He announced his retirement from NASA on March 26, 2009...
, director of NASA's Marshall Space Flight Center
Marshall Space Flight Center
The George C. Marshall Space Flight Center is the U.S. government's civilian rocketry and spacecraft propulsion research center. The largest center of NASA, MSFC's first mission was developing the Saturn launch vehicles for the Apollo moon program...
stated that NASA has considered DIRECT as well as many other rocket proposals, and that the Ares family
Ares (rocket)
In terms of rocketry, Ares could mean:*Three Shuttle-Derived Launch Vehicles under development for NASA's Project Constellation program:**The Ares I Crew Launch Vehicle , designed to launch the Orion ....
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 NASA statements of no special studies on DIRECT, the space agency released some internal studies conducted in 2006 and 2007. Nearly a year later, on May 18, 2009, the DIRECT team released a 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
International Space Development Conference
The International Space Development Conference is the annual conference of the National Space Society . Now in its 30th year, these conferences connect the general public and the NSS membership with leaders of contemporary space efforts...
in Orlando, Florida
Orlando, Florida
Orlando is a city in the central region of the U.S. state of Florida. It is the county seat of Orange County, and the center of the Greater Orlando metropolitan area. According to the 2010 US Census, the city had a population of 238,300, making Orlando the 79th largest city in the United States...
entitled, "Direct 3.0: Landing Twice the Mass on the Moon at Half the Cost." In April 2009, following NASA trade studies comparing use of the Space Shuttle Main Engine
Space Shuttle main engine
The RS-25, otherwise known as the Space Shuttle Main Engine , is a reusable liquid-fuel rocket engine built by Pratt & Whitney Rocketdyne for the Space Shuttle, running on liquid hydrogen and oxygen. Each Space Shuttle was propelled by three SSMEs mated to one powerhead...
(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 was due to concerns that the ablatively
Ablation
Ablation is removal of material from the surface of an object by vaporization, chipping, or other erosive processes. This occurs in spaceflight during ascent and atmospheric reentry, glaciology, medicine, and passive fire protection.-Spaceflight:...
-cooled RS-68 would not survive the intense heat produced by the nearby exhaust plumes of the Space Shuttle SRBs. 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. Similarly, for the upper stage, the DIRECT Team recommends using six of the flight-proven RL10B-2 engine.
In May 2009 the Office of Science and Technology Policy
Office of Science and Technology Policy
The Office of Science and Technology Policy is an office in the Executive Office of the President , established by Congress on May 11, 1976, with a broad mandate to advise the President on the effects of science and technology on domestic and international affairs.The director of this office is...
announced the Review of United States Human Space Flight Plans Committee
Review of United States Human Space Flight Plans Committee
The Review of United States Human Space Flight Plans Committee was a group reviewing the human spaceflight plans of the United States...
to be chaired by Norman R. Augustine
Norman Ralph Augustine
Norman Ralph Augustine is a U.S. aerospace businessman who served as Under Secretary of the Army from 1975-77. Augustine currently serves as chairman of the Review of United States Human Space Flight Plans Committee.-Career:...
. On 17 June 2009, team member Stephen Metschan presented the DIRECT v3.0 concept to the Committee, which was formed to offer independent advice to the incoming Obama Administration
Presidency of Barack Obama
The Presidency of Barack Obama began at noon EST on January 20, 2009 when he became the 44th President of the United States. Obama was a United States Senator from Illinois at the time of his victory over Arizona Senator John McCain in the 2008 presidential election...
. The Committee's final report did not directly compare DIRECT to the Constellation Program, but did offer budget, schedule, and mission combinations where a shuttle-derived launch vehicle could be used.
On 19 January 2010, amid rumors that NASA would propose a DIRECT-like inline launch vehicle, the DIRECT team made a presentation to NASA Associate Administrator for Exploration Systems Mission Directorate, Douglas Cooke, and NASA Associate Administrator for Space Operations, William H. Gerstenmaier
William H. Gerstenmaier
William H. Gerstenmaier has been the Associate Administrator for Space Operations for NASA since 2005. Prior to being Associate Administrator, Gerstenmaier served as the International Space Station Office Program Manager, at Johnson Space Center, a position he began in June 2002.-Early...
, in a meeting convened by NASA Administrator Charles F. Bolden, Jr.
Charles F. Bolden, Jr.
Charles Frank "Charlie" Bolden, Jr. is the current Administrator of NASA, a retired United States Marine Corps major general, and former NASA astronaut....
Design Considerations
Integrated Approach
According to the DIRECT team, many NASA engineers and managers have supported the concept and have completed a cost analysis comparison with NASA's current Constellation program 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 FacilityMichoud Assembly Facility
The Michoud Assembly Facility is an 832-acre site owned by NASA and located in New Orleans East, a large district within the city of New Orleans, Louisiana, United States. Organizationally, it is part of NASA's Marshall Space Flight Center...
and the various launch-processing facilities currently at the Kennedy Space Center
Kennedy Space Center
The John F. Kennedy Space Center is the NASA installation that has been the launch site for every United States human space flight since 1968. Although such flights are currently on hiatus, KSC continues to manage and operate unmanned rocket launch facilities for America's civilian space program...
. DIRECT proposes to re-use nearly all of the existing facilities with minimal modifications in contrast to the Ares I
Ares I
Ares I was the crew launch vehicle that was being developed by NASA as part of the Constellation Program. The name "Ares" refers to the Greek deity Ares, who is identified with the Roman god Mars...
and Ares V
Ares V
The Ares V was the planned cargo launch component of the Constellation program, which was to have replaced the Space Shuttle after its retirement in 2011. Ares V was also planned to carry supplies for a human presence on Mars...
rockets which will require extensive modifications and replacements over existing facilities.
The DIRECT's core stage would remain at the existing 8.41 m (27.6 ft) diameter of the Shuttle's External Tank compared to 10.06 m (33 ft) for Ares V. The DIRECT team claims that by not increasing the core stage diameter the existing External Tank manufacturing tooling at the Michoud Assembly Facility
Michoud Assembly Facility
The Michoud Assembly Facility is an 832-acre site owned by NASA and located in New Orleans East, a large district within the city of New Orleans, Louisiana, United States. Organizationally, it is part of NASA's Marshall Space Flight Center...
, the existing Pegasus barge used to transport the tank from Michoud to Kennedy Space Center
Kennedy Space Center
The John F. Kennedy Space Center is the NASA installation that has been the launch site for every United States human space flight since 1968. Although such flights are currently on hiatus, KSC continues to manage and operate unmanned rocket launch facilities for America's civilian space program...
, the existing work platforms in the Vehicle Assembly Building
Vehicle Assembly Building
The Vehicle Assembly Building, or VAB, at NASA's Kennedy Space Center was used to assemble and house American manned launch vehicles from 1968-2011. It is the fourth largest building in the world by volume...
, the existing Mobile Launcher Platform
Mobile Launcher Platform
The Mobile Launcher Platform or MLP is one of three two-story structures used by NASA to support the Space Shuttle stack during its transportation from the Vehicle Assembly Building to Launch Pad 39-A at the Kennedy Space Center as well as serve as the vehicle's launch platform...
s and Crawler-Transporter
Crawler-Transporter
The crawler-transporters are a pair of tracked vehicles used to transport spacecraft from NASA's Vehicle Assembly Building along the Crawlerway to Launch Complex 39. They were originally used to transport the Saturn IB and Saturn V rockets during the Apollo, Skylab and Apollo–Soyuz programs....
s, and parts of the structure of the existing Fixed Service Structure and Flame Trenches at Launch Complex 39 could be used without major modifications.
Ares I/V Costs
One of the strongest programmatic criticisms with the current Ares IAres I
Ares I was the crew launch vehicle that was being developed by NASA as part of the Constellation Program. The name "Ares" refers to the Greek deity Ares, who is identified with the Roman god Mars...
and Ares V
Ares V
The Ares V was the planned cargo launch component of the Constellation program, which was to have replaced the Space Shuttle after its retirement in 2011. Ares V was also planned to carry supplies for a human presence on Mars...
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
Ares I
Ares I was the crew launch vehicle that was being developed by NASA as part of the Constellation Program. The name "Ares" refers to the Greek deity Ares, who is identified with the Roman god Mars...
alone is expected to cost up to $14.4 billion to develop. Former NASA Administrator Michael D. Griffin
Michael D. Griffin
Michael Douglas Griffin is an American physicist and aerospace engineer. From April 13, 2005 to January 20, 2009 he served as Administrator of NASA, the space agency of the United States...
confirmed that the total cost for developing both Ares launchers would be $32 billion, indicating that the Ares V
Ares V
The Ares V was the planned cargo launch component of the Constellation program, which was to have replaced the Space Shuttle after its retirement in 2011. Ares V was also planned to carry supplies for a human presence on Mars...
will be more expensive to develop than the Ares I
Ares I
Ares I was the crew launch vehicle that was being developed by NASA as part of the Constellation Program. The name "Ares" refers to the Greek deity Ares, who is identified with the Roman god Mars...
.
The disadvantage of one launcher for two very different roles was pointed out by David King
David A. King
David A. King was the tenth Director of the NASA Marshall Space Flight Center located in Huntsville, Alabama. He was appointed to the position on June 15, 2003. He announced his retirement from NASA on March 26, 2009...
, director of NASA's Marshall Space Flight Center
Marshall Space Flight Center
The George C. Marshall Space Flight Center is the U.S. government's civilian rocketry and spacecraft propulsion research center. The largest center of NASA, MSFC's first mission was developing the Saturn launch vehicles for the Apollo moon program...
. "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."
Ares I Schedule
The schedule for Ares IAres I
Ares I was the crew launch vehicle that was being developed by NASA as part of the Constellation Program. The name "Ares" refers to the Greek deity Ares, who is identified with the Roman god Mars...
has incurred several delays since the inception of the new lunar program. The original intent in the Exploration Systems Architecture Study
Exploration Systems Architecture Study
The Exploration Systems Architecture Study is the official title of a large-scale, system level study released by the National Aeronautics and Space Administration in November 2005 in response to American president George W...
(ESAS) Report was to have a crewed flight as early as mid-2011 after the Space Shuttle retirement in 2010. The official current NASA schedule has a 65% confidence that the first manned flight of Ares I with Orion (Orion 2
Orion 2
Orion 2 may refer to:* a proposed Project Constellation spaceflight* the Orion 2 Space Observatory* the star 2 Orionis...
) will occur in March 2015.
The critical
Critical path method
The critical path method is an algorithm for scheduling a set of project activities. It is an important tool for effective project management.-History:...
activity of Ares I
Ares I
Ares I was the crew launch vehicle that was being developed by NASA as part of the Constellation Program. The name "Ares" refers to the Greek deity Ares, who is identified with the Roman god Mars...
development is currently the schedule for the J-2X upper stage engine and the five-segment version of the SRB
Space Shuttle Solid Rocket Booster
The Space Shuttle Solid Rocket Boosters were the pair of large solid rockets used by the United States' NASA Space Shuttle during the first two minutes of powered flight. Together they provided about 83% of liftoff thrust for the Space Shuttle. They were located on either side of the rusty or...
. Engineers are concerned about thrust oscillation and Orion-Ares I integration. In 2008, Lockheed Martin requested that NASA redesign Ares I
Ares I
Ares I was the crew launch vehicle that was being developed by NASA as part of the Constellation Program. The name "Ares" refers to the Greek deity Ares, who is identified with the Roman god Mars...
in order to end integration risks with the Orion crew capsule. The combined test results from the Ares I-X launch and the Ares I static test firing now indicate that thrust oscillation is not a critical issue, according to program engineers.
DIRECT Self Comparison to Ares
DIRECT contends that the requirement to develop 5-segment SRBs and the J-2X upper stage engine for Ares IAres I
Ares I was the crew launch vehicle that was being developed by NASA as part of the Constellation Program. The name "Ares" refers to the Greek deity Ares, who is identified with the Roman god Mars...
in order to fly the first Orion is directly responsible for the delays in schedule and the comparatively high development costs. All-new manufacturing at the Michoud Assembly Facility
Michoud Assembly Facility
The Michoud Assembly Facility is an 832-acre site owned by NASA and located in New Orleans East, a large district within the city of New Orleans, Louisiana, United States. Organizationally, it is part of NASA's Marshall Space Flight Center...
and launch facilities at Kennedy Space Center
Kennedy Space Center
The John F. Kennedy Space Center is the NASA installation that has been the launch site for every United States human space flight since 1968. Although such flights are currently on hiatus, KSC continues to manage and operate unmanned rocket launch facilities for America's civilian space program...
are also required for Ares I. In contrast, DIRECT proposes to reuse the existing 4-segment fully human rated Space Shuttle Solid Rocket Booster
Space Shuttle Solid Rocket Booster
The Space Shuttle Solid Rocket Boosters were the pair of large solid rockets used by the United States' NASA Space Shuttle during the first two minutes of powered flight. Together they provided about 83% of liftoff thrust for the Space Shuttle. They were located on either side of the rusty or...
and Space Shuttle Main Engine
Space Shuttle main engine
The RS-25, otherwise known as the Space Shuttle Main Engine , is a reusable liquid-fuel rocket engine built by Pratt & Whitney Rocketdyne for the Space Shuttle, running on liquid hydrogen and oxygen. Each Space Shuttle was propelled by three SSMEs mated to one powerhead...
. DIRECT also proposes reuse of existing manufacturing to build a modified variant of the existing Space Shuttle External Tank
Space Shuttle external tank
A Space Shuttle External Tank is the component of the Space Shuttle launch vehicle that contains the liquid hydrogen fuel and liquid oxygen oxidizer. During lift-off and ascent it supplies the fuel and oxidizer under pressure to the three Space Shuttle Main Engines in the orbiter...
. Only moderate modifications would be required at Kennedy Space Center
Kennedy Space Center
The John F. Kennedy Space Center is the NASA installation that has been the launch site for every United States human space flight since 1968. Although such flights are currently on hiatus, KSC continues to manage and operate unmanned rocket launch facilities for America's civilian space program...
to enable launches. DIRECT’s proposal for a single launch vehicle removes the program risks associated with the possible cancellation of the Ares V launcher due to budgetary constraints.
DIRECT asserts its Jupiter launchers avoid the delays of Ares I by not requiring the J-2X on the first-generation Jupiter-130 vehicle, by not requiring the five-segment SRB
Space Shuttle Solid Rocket Booster
The Space Shuttle Solid Rocket Boosters were the pair of large solid rockets used by the United States' NASA Space Shuttle during the first two minutes of powered flight. Together they provided about 83% of liftoff thrust for the Space Shuttle. They were located on either side of the rusty or...
and by providing more than 60 t of lift performance that would ameliorate weight issues on the Orion design.
DIRECT also claims that money would be saved by avoiding a parallel development of the Ares V
Ares V
The Ares V was the planned cargo launch component of the Constellation program, which was to have replaced the Space Shuttle after its retirement in 2011. Ares V was also planned to carry supplies for a human presence on Mars...
booster, since the Jupiter family would represent a single rocket family program. The group suggests that the money saved on Ares V be reused to speed development work of such other elements as the Orion, the 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 trimmed substantially, allowing full operational capability of an Orion/Jupiter-130 system to perform 6-person crew rotations and cargo deliveries to the ISS
International Space Station
The International Space Station is a habitable, artificial satellite in low Earth orbit. The ISS follows the Salyut, Almaz, Cosmos, Skylab, and Mir space stations, as the 11th space station launched, not including the Genesis I and II prototypes...
by 2013.
Cost Savings and Space Shuttle Gap
Proponents assert that the DIRECT proposal would enable NASA to fulfill the mandate of the Vision for Space ExplorationVision for Space Exploration
The Vision for Space Exploration is the United States space policy which was announced on January 14, 2004 by President George W. Bush. It is seen as a response to the Space Shuttle Columbia disaster, the state of human spaceflight at NASA, and a way to regain public enthusiasm for space...
sooner and more safely than the planned Ares I and Ares V, at a lower cost and with less programmatic risk due to a simpler approach which decreases new development efforts. Advocates say the DIRECT proposal would allow NASA to provide sufficient money to continue funding programs beyond launch vehicle development and operation, including extending its participation in the International Space Station
International Space Station
The International Space Station is a habitable, artificial satellite in low Earth orbit. The ISS follows the Salyut, Almaz, Cosmos, Skylab, and Mir space stations, as the 11th space station launched, not including the Genesis I and II prototypes...
, which is scheduled to end in 2016 as of 2009. The DIRECT proposal also suggests that NASA uses costs savings from the DIRECT proposal to accelerate the VSE's
Vision for Space Exploration
The Vision for Space Exploration is the United States space policy which was announced on January 14, 2004 by President George W. Bush. It is seen as a response to the Space Shuttle Columbia disaster, the state of human spaceflight at NASA, and a way to regain public enthusiasm for space...
schedule for returning to the Moon and to potentially fly other missions such as servicing missions to the Hubble Space Telescope.
In contrast to these claims, NASA senior manager for the STS program, John Shannon has stated that he thinks the DIRECT proposal underestimates the costs for the Jupiter rocket family.
Orbital Assembly Steps
Currently, the DIRECT proposal requires more orbital assembly steps than the current proposed Constellation Program. In Constellation, after Low Earth Orbital rendezvous of Ares I and Ares V, the Orion Crew Exploration Vehicle (approximately 22 t) from the Ares I would invert and dock with the Altair lunar lander (approximately 44 t) which would still be attached to the Ares V Earth Departure Stage. In the case of DIRECT, the combined mass of Orion and Altair exceeds the carrying capacity of the Jupiter-130. If a Jupiter-130 were launched with Orion and a Jupiter-246 launched with Altair, the Jupiter Upper Stage (JUS) with Altair would have insufficient propellant to push Altair/Orion beyond Earth orbit. Thus, the current DIRECT baseline is to launch two Jupiter-246s, one with a partially fueled (75 t) JUS carrying Orion/Altair and the other with only a fully fueled (175 t) JUS. After orbital rendezvous, the Orion would invert and re-dock with Altair much like in the Apollo Program and Constellation Program. However, with DIRECT, the crew in Orion would have to separate Orion/Altair from the first JUS and dock Altair to the second JUS. The second JUS would have enough remaining propellant to serve as the Earth Departure Stage. The first JUS would be discarded in Low Earth Orbit, while the second would be discarded after its Earth departure burn.Jupiter Upper Stage Mass
The Jupiter Upper Stage (JUS) mass to propellant capacity has been regarded as realistic. Minimal upper stage mass is desirable so that the stage may propel the Orion and Altair spacecraft out of Earth orbit, but the JUS must be made large enough to carry enough propellant to both achieve low Earth Orbit and to serve as the Earth departure stage. The DIRECT v3.0 JUS has a mass of 11.3 t for a propellant capacity of 175.5 t. While claiming a design heritage from the CentaurCentaur (rocket stage)
Centaur is a rocket stage designed for use as the upper stage of space launch vehicles. Centaur boosts its satellite payload to geosynchronous orbit or, in the case of an interplanetary space probe, to or near to escape velocity...
series of upper stages, DIRECT specifically cites new materials, new welding techniques, and a common bulkhead separating the Liquid Oxygen and Liquid Hydrogen tanks as sufficient to account for the low stage mass. Bernard Kutter of United Launch Alliance
United Launch Alliance
United Launch Alliance is a joint venture of Lockheed Martin and Boeing. ULA was formed in December 2006 by combining the teams at these companies which provide spacecraft launch services to the government of the United States. U.S...
described the even more radical DIRECT v2.0 JUS design as, "...very reasonable. I’d even call it conservative."
Payload Capacity
The payload capacity of Ares V to low earth orbit, according to NASA, is 188,000 kg. This is more than the largest proposed Jupiter rocket (Jupiter-246 Heavy with 5 segment SRBS) which is claimed to lift about 120,000 kg to LEO. For potential Mars missions more launches per mission would thus be required using Jupiter instead of Ares V and the mission modules would need to be separated in more different parts. However, NASA's Design Reference Mission 5.0Manned mission to Mars
A manned mission to Mars has been the subject of science fiction, engineering, and scientific proposals throughout the 20th century and into the 21st century...
completed in 2007 only requires a 125mt+ launch vehicle with a 10m+ diameter shroud for a Mars mission with 6 separate Ares V launches. The Jupiter rocket fulfills the requirements of the Design Reference Mission with only a very narrow shortfall in payload to LEO, while fulfilling the volume requirements.
The Jupiter rockets are shorter in height than the Ares V, permitting very long payload fairings and thus greater total internal volume than possible with the taller Ares V which quickly encounters restraints due to height limitations within the Vehicle Assembly Building
Vehicle Assembly Building
The Vehicle Assembly Building, or VAB, at NASA's Kennedy Space Center was used to assemble and house American manned launch vehicles from 1968-2011. It is the fourth largest building in the world by volume...
at Kennedy Space Center
Kennedy Space Center
The John F. Kennedy Space Center is the NASA installation that has been the launch site for every United States human space flight since 1968. Although such flights are currently on hiatus, KSC continues to manage and operate unmanned rocket launch facilities for America's civilian space program...
.
See also
- National Launch SystemNational Launch SystemThe National Launch System was a study authorized in 1991 by President George H. W. Bush to outline alternatives to the Space Shuttle for access to Earth Orbit. Shortly thereafter, NASA asked Lockheed Missiles and Space, McDonnell Douglas, and TRW, to perform a ten-month study...
- NASA Advanced Space Transportation ProgramNASA Advanced Space Transportation ProgramThe Advanced Space Transportation Program is a NASA program which is developing future space transportation systems. The ASTP's work, or purpose, is to intentionally advance current technologies, and innovate novel technologies, through intense research efforts that culminate in regularizing the...
- Shuttle-Derived Heavy Lift Launch VehicleShuttle-Derived Heavy Lift Launch VehicleThe Shuttle-Derived Heavy Lift Launch Vehicle, also known as the High Confidence Heavy Lift Launch Vehicle is an alternate launch vehicle proposal for the NASA Constellation program...
- Space Launch SystemSpace Launch SystemThe Space Launch System, or SLS, is a Space Shuttle-derived heavy launch vehicle being designed by NASA, following the cancellation of the Constellation Program, to replace the retired Space Shuttle. The NASA Authorization Act of 2010 envisions the transformation of the Ares I and Ares V vehicle...
- Jupiter (rocket family)Jupiter (rocket family)The Jupiter family of Heavy Lift Launch Vehicles is part of the proposed DIRECT Shuttle-Derived Launch Vehicle architecture. It is intended to be an alternative to the Ares I and Ares V rockets which were under development for the United States National Aeronautics and Space Administration's ...