- \n
- Constellation Forum Sections<\/li>\n
- L2 Shuttle Extension Section)<\/li>\n
- L2 Ares\/Orion Sections (over several hundred gbs in size)<\/li>\n
- Click here to Join L2<\/li>\n<\/ul>\n
\u201cWith the addition of a robust launch abort system, we believe both Atlas and Delta can exceed stringent NASA Loss of Crew requirements. Both launch vehicles offer unique advantages for a commercial crew development program, or for the launch of the Orion Crew Exploration Vehicle.\u201d<\/p>\n
Playing to the key strength of flight history, the paper emphasizes the key difference between the current forward plan of Ares, and its Shuttle Derived Heavy Lift Launch Vehicle alternatives.<\/p>\n
(adsbygoogle = window.adsbygoogle || []).push({});<\/p>\n
\u201cExisting launch vehicles offer a number of benefits, most notably the demonstrated reliability offered by continuing uncrewed launches during on-going operations,\u201d the paper continues. \u201cThis is evident in the significant reduction in the historical infant mortality rate of new launch vehicles. Design flaws manifest themselves in early flights, which is minimized by the evolutionary design approach demonstrated by Atlas and Delta.<\/p>\n
\u201cThis means that with a common fleet of launch vehicles, the uncrewed missions bear the first flight risk, thus significantly reducing the risk for crewed missions.<\/p>\n
\u201cThis illustrates the demonstrated reliability benefits of a common fleet of launch vehicles. Additionally, by 2015, the current Ares\/Orion ILC, Delta IV will have flown over 50 Common Booster Cores, including 8 Delta IV-Heavy vehicles. Atlas V will have flown nearly 65 times.\u201d<\/p>\n
Citing the basis of their confidence on safety, the paper expands on the three primary factors of Human Rating a vehicle \u2013 specifically launch vehicle reliability, the addition of an Emergency Detection System, and intact abort capability.<\/p>\n
\u201cThe combination of these three elements provides a common-sense, system-level approach to accomplish the goal of safe, reliable transportation to LEO.\u201d<\/p>\n
For EELV HR references:
\nhttp:\/\/www.nasaspaceflight.com\/2009\/04\/study-eelv-capable-orion-role-griffin-claims-alternatives-fiction\/
\nhttp:\/\/www.nasaspaceflight.com\/2007\/01\/human-rated-atlas-v-for-bigelow-space-station-details-emerge\/
\nhttp:\/\/www.nasaspaceflight.com\/2007\/04\/spacedev-announce-dream-chaser-agreement-with-ula-atlas-v\/<\/p>\nGap Reduction:<\/p>\n
Currently, Orion won\u2019t be launched on its debut flight (IOC \u2013 Initial Operating Capability) via Ares I until March, 2015 \u2013 at the very earliest, due to a low confidence level. Another year will pass before Orion 4\u2019s (FOC \u2013 Full Operating Capability) flight to the International Space Station (ISS).<\/p>\n
![\"ULA13\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2009\/09\/ULA13.jpg\" "\\"ULA13\\"")
This \u201cgap\u201d between the previously scheduled 2010 retirement of the shuttle and Orion\u2019s working schedule is one of the key concerns facing NASA, and indeed at the Augustine Committee\u2019s review into the future of the US\u2019 Human Space Flight plans.<\/p>\nAn argument often made relates to changing course after several years of Ares development and several billion dollars of expenditure. More so, it has been argued that moving to a different launch vehicle architecture now would actually increase the gap between the shutte\u2019s retirement \u2013 now likely in 2011 \u2013 and the operational capability of its successor.<\/p>\n
ULA counter this, claiming they have a proven history of being able to refine their family of vehicles for manned flight in a timescale that would result in Atlas V being ready to launch Orion in less than four years.<\/p>\n
\u201cAtlas and Delta have a long history of successful launch vehicle development and launch pad activation. ULA has built on that experience by developing a detailed plan and schedule to provide crew launch services for NASA and commercial providers. Based on our understanding of the requirements, we believe that that an Atlas V can be ready for commercial Human Spaceflight in less than 4 years and that the Delta IV-Heavy can be ready to launch Orion in 4-1\/2 years.<\/p>\n
\u201cThese schedules are consistent with the US experience during the Mercury-Atlas and Gemini-Titan Program experience, both of which flew the first manned mission within 4 years of the selection of the launch vehicle.\u201d<\/p>\n
Outlining the elements of their current ground and launch systems for the purpose of conforming to the Human Rating requirements, the paper cites the need for modifications to be carried out at the launch site, plus redundancy\/safety upgrades, and the inclusion of an Emergency Detection System (EDS).<\/p>\n
\u201cWe anticipate that this system will be similar for either Atlas or Delta, and will use the recent Atlas V Fault Tolerant Inertial Navigation Unit (FTINU) as the point of departure for design and development,\u201d the paper added on the specific note on the EDS.<\/p>\n
\u201cThe FTINU was developed in less than 3 years and was launched on an Atlas 551 for the NASA Pluto New Horizon mission in 2006. With EELV vehicle subsystem highly characterized, and with added flights-of-opportunity to check out the EDS (without its LAS) EELV has lowered schedule, technical, and cost risk for EDS development.\u201d<\/p>\n
All of which factors in to the EELV\u2019s Loss of Mission (LOM)\/Loss of Crew (LOC) ratings, which range from the Atlas V 401\u2019s rating of 1\/250 for a LOM and 1\/2500 for LOC, to the Delta IV-Heavy\u2019s 1\/80 LOM and 1\/800 for LOC, although the table notes that all the values represent 50 percent confidence level \u2013 in part due to Delta IV\u2019s lack of flights.<\/p>\n
\u201cSystem reliability was one of the most important design considerations for the EELV systems, Atlas V and Delta IV. It was one of only four critical performance parameters specified by the Operational Requirements Document (ORD),\u201d added the paper on the LOM and LOC values. \u201cAs such, a tremendous amount of effort was expended to develop credible reliability estimates to prove that the requirements were met.<\/p>\n
\u201cProbabilistic Risk Assessment (PRA) type analysis was used to determine so-called design reliability. But mission reliability, what the program called the true reliability, was calculated by applying a Bayesian update to incorporate actual flight experience of similar systems or subsystems.<\/p>\n
\u201cThis approach was arrived at through lengthy technical interchanges between the EELV contractors and the Aerospace Corporation, representing the Air Force customer. The results of the analysis (are based) with the associated LOC numbers assuming the probability of a failed abort is 1\/10.\u201d<\/p>\n
For CxP Gap References:
\nhttp:\/\/www.nasaspaceflight.com\/news\/constellation\/<\/p>\nAtlas V vs Delta IV Human Rating:<\/p>\n
With the paper continuing by citing the attributes of both the Atlas V and Delta IVs on preference for which vehicle would be best to Human Rate.<\/p>\n
![\"Atlas](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2009\/09\/ULA11.jpg\" "\\"Atlas")
Atlas V has numerous benefits, not least due to the minimal modifications the vehicle would require to launch humans into space, with only ground support and the addition of a EDS required.<\/p>\n\u201cThe Atlas V 401 and 402 vehicles are well suited for commercial human spaceflight. They are simple, low cost, reliable systems with a long successful heritage. They use two flight proven propulsion systems (RD-180 & RL-10), with only two engine starts, and two separation events.<\/p>\n
\u201cThey have benign, well characterized environments, robust margins, and high demonstrated reliability (100% for the 401) and design reliability (.9960 for the 401 and .9942 for a 402). Atlas 401 and 402 can provide up to approximately 27,500lbs of performance to LEO, depending on the specific configuration of the crew vehicle.<\/p>\n
\u201cTrajectories can easily be shaped to eliminate \u2018Black Zones\u2019 with no appreciable impact to performance. (\u2018Black Zones\u2019 are defined as any period of flight when an abort would result in unsafe landing conditions if: 1) the aborting capsule falls into hostile terrain; or 2) High-g loads occur during a reentry.<\/p>\n
\u201cAtlas V can accommodate commercial human spaceflight with no changes to the existing vehicles. The only enhancements will be the addition of the Emergency Detection System and changes to the Mobile Launch Platform to allow crew ingress and egress. Once a particular crew vehicle is selected, Atlas V will conduct a series of analyses and system testing to integrate vehicle on a 401 or 402. These include Hazard Analyses, Design Margin Analyses and Mission Unique Analyses specific for the Crew vehicle configuration.<\/p>\n
\u201cIn addition, we may conduct wind tunnel tests and subsequent aerodynamics and loads analyses to ensure that we maintain our existing vehicle margins. The Atlas V 4XX offers the lowest risk, lowest cost solution for commercial crew.<\/p>\n
\u201cThe demonstrated reliability record and robust vehicle design allows Atlas the flexibility to meet the needs of a variety of commercial crew vehicles currently being contemplated and designed.\u201d<\/p>\n
![\"ULA12\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2009\/09\/ULA12.jpg\" "\\"ULA12\\"")
Delta IV-H wins on performance, with over 4 metric ton of margin for both ISS and Lunar Orion delivery, even after taking into account the elimination of black zones \u2013 often cited by Constellation as one of EELV\u2019s main flaws in being able to Human Rate.<\/p>\n\u201cThe Delta IV has ample performance margin. For the ISS crew mission, based on current Orion weight allocations, the Delta IV Heavy has 4.8t of margin for lifting the Orion capsule to the ISS delivery orbit. This drops to 4.3t of margin for the Lunar Crew delivery mission. These 20 percent margins are very healthy, especially given that Orion would be flying on a demonstrated launch vehicle.<\/p>\n
\u201cThese margins are after depressing the trajectories to close all Black Zones. (Performance margins would have been ~1t higher if this had not been done.) These performance margins are so big that they can cover almost any conceivable human rating penalty, or combination of penalties, including a 1.40 safety factor, and significant RL-10 derating.<\/p>\n
\u201cNASA has now acknowledged that they believe that the Delta IV Heavy has adequate performance margin and no Black Zones. This should refocus any questions about EELV compatibility onto human rating, reliability, and schedule.<\/p>\n
\u201cThe human rated Delta IV Heavy fundamentally is the same Delta IV vehicle that has flown successfully three times, and is expected to fly 10 times by the projected mid 2014 IOC date. (32 total Delta IV CBC booster elements are projected to have flown by this same date.). This is a huge benefit from a crew safety standpoint.<\/p>\n
\u201cThough there are many measures of reliability, demonstrated reliability is the least subjective measure. Even with an analytic reliability which is higher, the EELVs cumulative launch total before the 2014 IOC, and additional accumulation of launches including DoD, means that the Ares 1 or another new vehicle might effectively never catch up with Delta\u2019s demonstrated reliability.\u201d<\/p>\n
However, more work is required on this vehicle when it comes to modifications in order to provide the necessary Human Rating safety additions \u2013 which would also need to satisfy the Delta IV\u2019s main customer at present, the Department Of Defense (DOD).<\/p>\n
\u201cDelta IV vehicle changes include removal of the fairing, and replacement with the Orion System, including service module and launch abort system and adapters. The Emergency Detection System will be incorporated into the launcher. An array of relatively small redundancy and safety modifications have been identified based on NASA requirements, but these remain modest in scope compared to the legacy design.<\/p>\n
\u201cWe anticipate these upgrades to be acceptable to the DoD customers, and expect these to be incorporated fleetwide with no need for a unique NASA vehicle design apart from the EDS kit. Currently 1.40 safety factor has been removed from NASA requirements, though a return to this requirement driving some regauging and requalification could be accommodated within the same proposed schedule.\u201d<\/p>\n
Numerous upgrades and modifications are listed, but also with cited uncertainty as to how many of the modifications would be required.<\/p>\n
\u201cThe details of redundancy upgrades on Delta remain an area of interest. Of note is that quite a few of the requirements are not driven by explicit redundancy requirements, but on other anticipated safety criteria as the desire to reduce the release of burning H2 at RS-68 start,\u201d added the paper.<\/p>\n
\u201cAlso, in some cases different redundancy upgrades (RS-68 backup valves, feedline prevalves, and hydraulics redundancy) need to be traded off to find the smartest implementation path. This makes the final suite of upgrades somewhat uncertain. However, the anticipated total scope and cost of these safety upgrades is programmatically small, with engine mods the most expensive due to high intrinsic recertification cost.<\/p>\n
\u201cGenerally speaking, schedule impacts on IOC (effecting the US human spaceflight \u201cgap\u201d) is a more significant consideration.\u201d<\/p>\n
One interesting line near the end of the \u201cAtlas and Delta Capabilities to Launch Crew to Low Earth Orbit\u201d paper is a reference to both vehicles being used to launch humans into space.<\/p>\n
\u201cThough we assume Orion on Delta IV, and commercial crew capsules on Atlas, the difference in human rating is intrinsic to the launch vehicles, and not to assumed differences in human rating requirements.\u201d<\/p>\n
In summary, the \u201cwinner\u201d of becoming a Human Rated launcher between the Atlas V and the Delta IV comes down to a question of schedule, risk numbers and performance.<\/p>\n
\u201cThe EELVs are ready to support crew lift with flight proven vehicles that will have an even longer legacy of flights by the crewed IOC date with superior demonstrated reliability compared to any new system. Our schedules are grounded by ULA\u2019s unmatched legacy of vehicle development and modifications programs and launch pad developments,\u201d the paper summarizes.<\/p>\n
\u201cThe Atlas V, with the relatively minor addition of an Emergency Detection System and a dedicated NASA Vertical Integration Facility (VIF) and Mobile Launch Platform (MLP), is ready for commercial human spaceflight and complies with NASA human rating standards. The 3 1\/2 year integration span is likely shorter than the development for any new commercial capsule that might fly on it.<\/p>\n
\u201cThe Delta IV has ample performance to support the existing Orion vehicle, without Black Zones. The Delta IV can support a mid-2014 Crewed IOC, which is superior to Orion launch alternatives. The proposed 37A pad is a look-alike counterpart to the existing 37B pad with low development risk.<\/p>\n
\u201cHuman rating the Delta is a relatively modest activity, with the addition of an Emergency Detection System, an array of relatively small redundancy and safety upgrades, both in the vehicle and the engines that are minor compared to the original development of the Delta IV.\u201d<\/p>\n
An architecture complimented by fuel depots:<\/p>\n
ULA are proposing a change of direction that is unmatched by the other alternative architectures, combining the use of vehicles that are already flying, with an on orbit ability to refuel in space via fuel depots.<\/p>\n
![\"ULA6\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2009\/09\/ULA6.jpg\" "\\"ULA6\\"")
As a result, one of the greatest challenges vehicles face \u2013 the need to launch with all the propellant they intend to use on orbit \u2013 can be staged in space.<\/p>\n\u201cThe present ESAS architecture for lunar exploration is dependent on a large launcher. It has been assumed that either the ARES V or something similar, such as the proposed Jupiter \u2018Direct\u2019 lifters are mandatory for serious lunar exploration,\u201d another associated paper opened.<\/p>\n
\u201cThese launch vehicles require extensive development with costs ranging into the tens of billions of dollars and with first flight likely most of a decade away. In the end they will mimic the Saturn V programmatically: a single-purpose lifter with a single user who must bear all costs. This programmatic structure has not been shown to be effective in the long term. It is characterized by low demonstrated reliability, ballooning costs and a glacial pace of improvements.<\/p>\n
\u201cThe use of smaller, commercial launchers coupled with orbital depots eliminates the need for a large launch vehicle. Much is made of the need for more launches \u2013 this is perceived as a detriment. However since 75 percent of all the mass lifted to low earth orbit is merely propellant with no intrinsic value it represents the optimal cargo for low-cost, strictly commercial launch operations.<\/p>\n
\u201cThese commercial launch vehicles, lifting a simple payload to a repeatable location, can be operated on regular, predictable schedules. Relieved of the burden of hauling propellants, the mass of the Altair and Orion vehicles for a lunar mission is very small and can also be easily carried on existing launch vehicles. This strategy leads to high infrastructure utilization, economic production rates, high demonstrated reliability and the lowest possible costs.<\/p>\n
\u201cThis architecture encourages the exploration of the moon to be conducted not in single, disconnected missions, but in a continuous process which builds orbital and surface resources year by year. The architecture and vehicles themselves are directly applicable to Near Earth Object and Mars exploration and the establishment of a functioning depot at earth-moon L2 provides a gateway for future high-mass spacecraft venturing to the rest of the solar system.\u201d<\/p>\n
ULA provide a \u201cProposed Architecture Concept of Operations\u201d in the paper, which shows a logistics stream and a crew stream feeding off depots, including one at L2 (Lagrange point). However, the paper notes that \u201cthe architecture is illustrated using ULA vehicle concepts for convenience. In reality, no single industrial entity can entirely support this architecture.<\/p>\n
\u201cThe production and launch rates are simply not sustainable by a single team. It must be a concerted effort of several launch providers, perhaps a consortium linking industry and NASA.\u201d<\/p>\n
![\"ULA7\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2009\/09\/ULA7.jpg\" "\\"ULA7\\"")
The backbone of the architecture is the ACES (Advanced Common Evolved Stage), which is currently being developed by ULA, and expected to replace the three existing cryogenic upper stages presently being used.<\/p>\n\u201cContaining 41 mT of liquid hydrogen and liquid oxygen it is powered by four RL10 class engines. ACES builds on over 200 flights of Centaur and Delta, fusing technologies from both programs: sharing the Delta IV 200\u201d tank diameter but with a common\/nested intermediate bulkhead. ACES uses tank geometry, low conductivity tank structures, passive thermal protection and vapor cooling to suppress cryogenic propellant loss to boiloff,\u201d noted the paper.<\/p>\n
\u201cSince it is wholly protected from aeroloads during launch a thick MLI blanket surrounds every exposed surface \u2013 drastically reducing external heating. ACES has no helium or hydrazine systems- all pressurization, attitude control and power is generated by consuming its two main propellants. Most importantly ACES is designed to be refilled with propellants once in space.\u201d<\/p>\n
The 41 mT ACES propellant capacity is sized for usage with DoD, NASA science and commercial payloads. Because ACES sub-systems are concentrated on an aft mounted equipment deck the propellant capacity can be readily modified through changes in tank side wall length.<\/p>\n
However, thanks to the use of propellant depots lunar exploration can efficiently be accommodated with as few as two tank volumes, the basic 41 mT. ULA provide an outline of Orion riding with ACES, Altair with ACES and the ACES tanker.<\/p>\n
\u201cIn the Orion Service Module configuration, an ACES 41 is mated to an ECLSS module and the Orion Command Module. ACES provides its own power and that for Orion by consuming its ullage gases. Solar arrays and dedicated radiators are unneeded \u2013 ACES provides these services,\u201d the paper adds.<\/p>\n
\u201cAttitude control is provided by ACES working in concert with the Orion RCS (Reaction Control System). The Orion-peculiar services such as N2 replenish , CO2 scrubbing and voice communications are provided by the ECLSS module.<\/p>\n
\u201cIn the Altair configuration, ACES 41 is mated to a Lunar Cargo Module or the Crew Ascender as well as multiple 1,000 pound thrust lateral-facing engines and landing gear for the final hover and landing phases.<\/p>\n
![\"ULA8\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2009\/09\/ULA8.jpg\" "\\"ULA8\\"")
\u201cIn its simplest and most common configuration the ACES tanks are stretched so that they contain 71 tons of propellants. This ACES 71 vehicle has no payload attached and uses the very simplest of payload fairings. Its principle purpose is to deposit or remove propellants from a depot. The ACES tanker is capable of supporting propellants that are subcooled.<\/p>\n\u201cSubcooling of the LH2 and LO2 allows propellants to absorb heat while stored in LEO without saturation pressures rising excessively. This permits extended storage times in high heating conditions without suffering excessive mass losses.\u201d<\/p>\n
The result of this multi-use of the ACES system is the ability to create the fuel depots in space, which is an idea that was heavily supported by the Augustine Review panel.<\/p>\n
\u201cThe ACES depot is an ACES 41 mated to a modified ACES 71 Tanker. The tanker has a shifted intermediate bulkhead to maximize LH2 storage. The main engines have been removed and a high performance deployable sunshield installed. The LH2 storage element is launched empty as a payload on an Atlas 554 or Delta IV HLV,\u201d the paper continues.<\/p>\n
\u201cBecause it is not filled with cryogenic propellants on the ground it can dispense with external conductive insulation such as foam. Its thermal protection is strictly optimized for vacuum operations. The depot provides the multiple interfaces for transferring propellants to and from the docked vehicles and can supply power and support services to those vehicles for extended periods.<\/p>\n
\u201cMultiple Orion, Altair and tanker vehicles can be simultaneously docked. The proposed architecture relies on two depots \u2013 one in LEO and the other at L2.<\/p>\n
\u201cBeing an empty shell the depot is extremely light, weighing approximately 12 mT. Launched on a Delta HLV results in nearly 20t of residual propellant remaining in the ACES 41 upper stage. Once in LEO, the ACES-41 residual LH2 is transferred into the LH2 depot tank. The ACES-41 LO2 residuals are then transferred to the now empty ACES-41 LH2 tank, after the tank has been evacuated of any residual H2.\u201d<\/p>\n
Other solutions are noted, such as a passive Thermal Protection System (TPS) for the depot in Low Earth Orbit (LEO), to protect against propellant boiloff, whereas the far lower heating rate for the depot at L2 can establish near-zero boiloff losses \u2013 amounting to a few pounds per day which also nearly matches the minimal station keeping requirements at the quasi stable L2.<\/p>\n
A dedicated paper further outlines the depot plan, and available options for alternative paths.<\/p>\n
Lunar Exploration:<\/p>\n
With the combination of the EELV heavy lift options and the fuel depots en route, the proposed path to returning to the moon involves the ACES\/Altair duo being launched on a Delta IV HLV booster with ACES\/Altair replacing the Delta IV upper stage providing a total LEO lift mass of 36t.<\/p>\n
![\"ULA10\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2009\/09\/ULA10.jpg\" "\\"ULA10\\"")
\u201cRefueled from the LEO depot the ACES\/Altair can deliver in excess of 30 tons of combined cargo and vehicle mass to L2,\u201d notes the paper. \u201cGenerally however it arrives at L2 with substantial propellant residual. If the Altair is intended to be cached at L2 for future crew use it deposits its propellants into the depot for efficient long term storage.\u201d<\/p>\nThe result of using depots at LEO and L2 would allow for 20mt and a crew of four astronauts to be landed on the lunar surface.<\/p>\n
\u201cThe ACES\/Altair is loaded or topped from the L2 depot just prior to lunar descent. This includes the loading of the Ascender propellant tanks which are used during the terminal hover\/landing phase. Fully loaded, it can deliver a combined mass of vehicles (such as the ascender), cargo and unused propellants greater than 40t to the lunar surface.<\/p>\n
\u201cThe ACES tanks on the landed descenders are used for cryogenic propellant storage on the lunar surface and just as at L2 they gradually build their stores. The cycle of power generation would be established with fuel cells active during the lunar night and solar systems during the day. The conversion of water to the reactants and back in rhythm with the lunar day would be established.<\/p>\n
\u201cThe support of a substantial crew on the lunar surface requires the storage, handling and transport of industrial quantities of reactants, water, sewage, nitrogen, scrubbed CO2, etc. The landed descenders each have substantial capacity to support the storage and processing of these materials and with each landing the ACES tanks are added to this lunar base tank farm.<\/p>\n
\u201cThe ability to close the local ecosystem would gradually increase with a subsequent reduction in lost mass. Transfer of fluids between tanks is enabled by the ability to move the ACES\/Altair after landing. It can be driven or towed to be adjacent to other landed vehicles so their systems can be joined.\u201d<\/p>\n
The paper outlines each of the paths required to launch the crew, pass them through the depots \u2013 including transportation to L2 \u2013 to the lunar surface and subsequent return to Earth. It also provides a roadmap for the move to the ACES system.<\/p>\n
\u201cACES first flight would occur with either a commercial or DoD payload nearly five years before the first crewed flight to the moon. The final six crew flights to ISS would be conducted using ACES and the Orion capsule. To demonstrate the lunar lander as quickly as possible a robotic lander mission is included in 2016 with a direct lunar descent.<\/p>\n
![\"ULA9\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2009\/09\/ULA9.jpg\" "\\"ULA9\\"")
\u201cInitial crewed landing would occur in 2018. Either a single crewed mission per year coupled with 20mT of cargo or two crewed missions per year can be supported within the anticipated budgets. The assumed cost of transport to LEO ranged from 9.2 to 10.2 $M\/mT depending on launch vehicle. This scenario also assumes the cost of flights to the ISS are included at a rate of 2\/year commencing in 2013.\u201d<\/p>\nExpanding on costs, one graph lays out the funding requirements for as far downstream as 2024.<\/p>\n
Four to five billion a year would cover the costs of development and operation through to 2017 \u2013 which includes lunar systems (which the current Constellation Program has been struggling to find monies for) \u2013 before rising to seven billion per year from 2020 to 2024.<\/p>\n
Lunar Lander \u2013 DTAL:<\/p>\n
At the center of the lunar landing plan is the DTAL \u2013 or Dual Thrust Axis Lander. The vehicle \u2013 which lands horizontally, uses an RL10 engine to accomplish the descent deceleration to just above the lunar surface. Final landing is accomplished using thrusters mounted along the DTAL body. ULA claim this configuration places the crew and payloads safely and conveniently close to the lunar surface.<\/p>\n
\u201cULA\u2019s Centaur and Delta IV upper stages provide an excellent cryogenic propulsion framework for developing a reliable, mass efficient lunar lander.<\/p>\n
\u201cInitial DTAL-enabled large robotic missions allow NASA to return to the moon quickly and demonstrate hardware to be used by crews that follow. This same mission design supports placement of large lunar base elements (habitats, power plants, rovers, excavation equipment, etc),\u201d the paper on the DTAL notes.<\/p>\n
\u201cAs the uncrewed missions are completed, and the system matures, astronauts will then use the same, now proven system to access the lunar surface.<\/p>\n
![\"ULA3\"](\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2009\/09\/ULA3.jpg\" "\\"ULA3\\"")
\u201cThe reliable DTAL propulsion stage provides the flexibility to visit destinations other than the moon. DTAL\u2019s mass and thermal efficient design provides the capability to visit NEO\u2019s or possibly even Mars. By supplying the life support consumables with O2 and H2 from the large primary propellant tanks long duration missions are possible.\u201d<\/p>\nThe DTAL looks completely different to the current Altair design that NASA are working on \u2013 although the Constellation Program have noted Altair is likely to change in design as it matures. Interestingly, it\u2019s that very design of Altair that reduces crew safety during their expeditions on to the lunar surface.<\/p>\n","protected":false},"excerpt":{"rendered":"
The United Launch Alliance (ULA) have created an expansive plan to utilize the Atlas and Delta Launch Vehicle families to provide the United States with an architecture that both reduces the gap and provides greater flexibility \u2013 when compared to NASA\u2019s current Ares-based plans. ULA\u2019s plans range from Low Earth Orbit (LEO) access, to the […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[2705,8184],"class_list":["post-40992","post","type-post","status-publish","format-standard","hentry","category-news","tag-eelv","tag-sls-orion"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/40992"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=40992"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/40992\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=40992"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=40992"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=40992"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}