Ares I
From Wikipedia, the free encyclopedia
 Artist's impression of Ares I launch |
|
| Function | man-rated orbital launch vehicle |
|---|---|
| Manufacturer | Alliant Techsystems (Stage I) Boeing (Stage II) |
| Country of origin | United States |
| Size | |
| Height | 94 m (309 ft) |
| Diameter | 5.5 m |
| Mass | TBC |
| Stages | 2 |
| Capacity | |
| Payload to LEO |
25,000 kg (55,000 lb) |
| Launch history | |
| Status | In Development |
| Launch sites | Kennedy Space Center, LC-39B |
| Total launches | 0 |
| Maiden flight | Scheduled for January 2014 |
| First Stage | |
| Engines | 1 Solid |
| Thrust | TBC |
| Burn time | ~150 seconds |
| Fuel | Solid |
| Second Stage | |
| Engines | 1 J-2X |
| Thrust | 1308 kN (294,000 lbf) |
| Burn time | TBC |
| Fuel | LH2/LOX |
Ares I is the crew launch vehicle being developed by NASA as a component of Constellation Program. NASA plans to use Ares I to launch Orion, the spacecraft being designed for NASA human spaceflight missions after the Space Shuttle is retired in 2010. Ares I was previously known as the Crew Launch Vehicle or CLV. Ares I will complement the larger, unmanned Ares V, which is the cargo launch vehicle for Constellation.
NASA selected the Ares designs for their anticipated overall safety, reliability and cost-effectiveness.[1] Ares I and V are named after the Greek deity Ares, who is identified with the Roman god Mars.
Contents |
[edit] Ares I’s role in Project Constellation
Ares I is the crew launch component of the Constellation program. Unlike the Space Shuttle, where both crew and cargo are launched simultaneously on the same rocket, the plans for Project Constellation outline having two separate launch vehicles, the Ares I and the Ares V, for crew and cargo, respectively. Having two separate launch vehicles will allow for more specialized designs for the different purposes the rockets will fulfill.
The Ares I rocket is specifically being designed to launch the Orion Crew Vehicle. Orion is intended as a crew capsule, similar in design to the Project Apollo capsule, to transport astronauts to the International Space Station, the Moon, and eventually Mars.
Although primarily designed to serve as a crew transportation vehicle — carrying a crew of four to six Constellation astronauts — Ares I might also deliver some (limited) resources to orbit, including supplies for the International Space Station or subsequent delivery to the planned lunar base.[1]
[edit] Design
[edit] First stage
The first stage is a more powerful and reusable solid fuel rocket derived from the current Space Shuttle Solid Rocket Booster (SRB). Compared with the current SRB, which has four segments, the most notable difference is the addition of a fifth segment. This fifth segment will enable the Ares I to produce more thrust and burn longer. Other changes made to the SRB are the removal of the Space Shuttle External Tank (ET) attachment points and the replacement of the SRB nosecone with a new forward adapter that will interface with the liquid-fueled second stage. The adapter will be equipped with solid-fueled separation motors to facilitate the disconnection of the stages during ascent.
[edit] Upper stage
The upper stage is to be propelled by one J-2X rocket engine fueled by liquid hydrogen (LH2) and liquid oxygen (LOX).[2] The J-2X is derived from the J-2 engine used on the Saturn IB and Saturn V rockets. On July 16, 2007, NASA awarded Rocketdyne a sole-source contract for the J-2X engines to be used for ground and flight tests.[3]
Originally, NASA was to use a Space Shuttle Main Engine, but due to the high costs (~US$55–60 million per engine), the need to redesign the engine to start up in both the air and in vacuum, and that the Ares I upper stage is expendable, the engine was dropped in favor of the J-2X, which is significantly less expensive (~US$20 million), and was designed from the beginning for high-altitude use.[citation needed]
Although its J-2X engine is derived from an established design, the upper stage itself is wholly new. Originally based on the internal structure of the Shuttle's External Tank, the original design called for separate fuel and oxidizer tanks, separated by an "intertank" structure. Using a concept going back to the Apollo era, the "intertank" structure was dropped to decrease mass, and instead, a common bulkhead would be used between the tanks. A recent design, currently under review, uses the savings to increase propellant capacity: with the common bulkhead, total propellant capacity would be 297,900 pounds (135,100 kg).[4] The increase in fuel mass is expected to decrease the initial acceleration of the second stage to around 0.6 g.[citation needed]
The upper portion of the upper stage includes an adapter assembly to mate with the Orion Crew Vehicle, and the lower section includes a thruster system, similar to that used on the Saturn IB and Saturn V rockets, to provide roll control for both the first and second stages of the vehicle during flight.[citation needed]
The only part of the Shuttle's External Tank on the Ares I upper stage is the spray-foam insulation. This will protect the cryogenic propellants from the warm, moist conditions found at Kennedy Space Center. This is the same insulation that broke off the Space Shuttle Columbia on launch, damaging the shuttle's re-entry shield and causing it to burn up on re-entry. The same risk does not exist in a rocket as there are no delicate components below the second stage that could be struck and damaged by a falling piece of insulation.[citation needed]
The upper stage of Ares I is to be built at the NASA Michoud Assembly Facility, the current location of the fabrication and construction of the Shuttle's External Tank, and the former construction site of the Saturn V's S-IC stage. On August 28, 2007, NASA awarded the Ares I Upper Stage manufacturing contract to The Boeing Company. Boeing built the S-IC stage at Michoud in the 1960s.[citation needed]
[edit] Development
[edit] Advanced Transportation System Studies
In 1995 Lockheed Martin produced for the Marshall Space Flight Center a report of work done under an Advanced Transportation System Studies (ATSS) contract. The executive summary for the ATSS report describes several possible vehicles much like the Ares I design, with liquid rocket second stages stacked above segmented SRB first stages.[5] The variants they considered included both J-2S and SSME engines for the second stage.
[edit] Exploration Systems Architecture Study
On 29 April 2005, after President Bush had announced the Vision for Space Exploration in January 2004, NASA chartered the Exploration Systems Architecture Study to accomplish a number of specific goals:[6]
- determine the "top-level requirements and configurations for crew and cargo launch systems to support the lunar and Mars exploration programs"
- assess the "CEV requirements and plans to enable the CEV to provide crew transport to the ISS"
- "develop a reference lunar exploration architecture concept to support sustained human and robotic lunar exploration operations"
- "identify key technologies required to enable and significantly enhance these reference exploration systems"
A Shuttle-derived launch architecture was selected by NASA for the Ares I. Originally, the vehicle would have used a 4-segment Solid Rocket Booster (SRB) for the first stage, and a simplified Space Shuttle Main Engine (SSME) for the second stage. An unmanned version, identical with the current design, would have used the 5-segment booster, but with the second stage using the single SSME.[citation needed]
But shortly after the initial design was approved, additional tests revealed that the Orion spacecraft would be too heavy for the 4-segment booster to lift. In January 2006, NASA announced they would slightly reduce the size of the Orion spacecraft, add a fifth segment to the solid-rocket first stage, and replace the single SSME with the Apollo-derived J-2X motor. While the switch from a 4-segment first stage to a 5-segment version would allow NASA to construct virtually identical motors (albeit with some segments being interchangeable), the main reason for the change to the 5-segment booster was the switch to the J-2X.[citation needed]
Both cost and functionality influenced NASA's decision to change to J-2X. At approximately US$20-25 million per engine, the Rocketdyne-designed and produced J-2X will cost less than half as much as the more complex SSME (around US$55 million). Unlike the current SSME, which was designed to start on the ground, the J-2X was designed from the start to be started in both mid-air and in near-vacuum. This air-start capability was critical, especially in the original J-2 engine used on the Saturn V's S-IVB stage, to propel the Apollo spacecraft to the Moon. The SSME, on the other hand, would have to undergo extensive modifications to be air-startable and to be able to restart in a vacuum (as the Ares I would fly a "direct-insertion" profile, and since the Orion spacecraft has limited fuel reserves), and would have to be "pre-fired" in a manner similar to the "Main Engine tests" conducted on the SSMEs prior to the maiden flights of each NASA orbiter and before the STS-26 flight in 1988.[citation needed]
NASA selected ATK Thiokol, the current builder of the Shuttle SRBs, as the prime contractor for the Ares I first stage.[7][8] Rocketdyne, a division of Pratt & Whitney, will be the main subcontractor for the J-2X rocket engine.
On January 4, 2007, NASA announced that the Ares I had completed its system requirements review, the first such review completed for any manned spacecraft design since the Space Shuttle.[9] This review is the first major milestone in the design process, and is intended to ensure that the Ares I launch system meets all the requirements necessary for Constellation Program. In addition to the release of the review, NASA also announced that a redesign in the tank hardware was made. Instead of separate LH2 and LO2 tanks, separated by an "intertank" like that on the Shuttle ET, the new LH2 and LOX tanks will be separated by a common bulkhead like that employed on the Saturn V S-II and S-IVB stages. This provides a significant mass saving and eliminates the need to design a second stage interstage unit that would have to carry the weight of the Orion spacecraft with it.[citation needed]
On December 12, 2007, NASA selected Boeing to provide and install the Ares Instrument Unit Avionics for the Ares I rocket.[10]
[edit] Schedule
NASA completed the Ares I system requirements review in January 2007.[9] Project design is to continue through the end of 2009, with development and qualification testing running concurrently through 2012. At the same time, flight articles are to begin production towards the end of 2009 for a first launch in June 2011. The first launch of a human is planned for September 2014.[11][12]
[edit] Issues
In January 2008, NASA Watch revealed that the first stage Solid Rocket Booster of the Ares I could create high vibrations during the first few minutes of ascent. The vibrations are caused by sudden acceleration pulses due to thrust oscillations inside the first stage.[13] NASA officials have known about the problem since fall 2007, stating in a press release that they had wanted to solve it by March 2008. NASA admitted that this problem is very severe, rating it four out of five on a risk scale. Still, NASA said they are very confident of solving this problem, referring to a long history of successful problem solving. NASA also outlined that this is a completely new transport system, like the Apollo or Space Shuttle systems were at their development, and that it is normal for such problems to arise during the development stage.[14][15][16]
[edit] Igniter tests
NASA has completed a successful test firing of the igniter for the Ares I engines on March 10, 2009. These will be used to start the first stage motor. The test was conducted at ATK Launch Systems test facilities near Promontory, Utah. This igniter test generated a flame approximately 200 feet in length. Preliminary data showed the igniter performed as planned. ATK Launch Systems, a division of Alliant Techsystems of Brigham City, Utah, is the prime contractor for the Ares I first stage.
The Ares I igniter is an advanced version of the flight-proven igniter used on the space shuttle's solid rocket boosters. The igniter takes advantage of upgraded liner and insulation materials that have improved thermal properties which protect the igniter's case from the burning solid propellant.[17]
[edit] Criticisms
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The neutrality of this article is disputed. Please see the discussion on the talk page. Please do not remove this message until the dispute is resolved. (May 2009) |
The proposed Ares I configuration has been criticized on several grounds. The production of a launch vehicle in the 25 tonnes (55,000 lb) payload class can be seen as direct competition with existing vehicles such as the Boeing Delta IV-Heavy and the Atlas V. It can be argued that lower costs and improved safety are likely to result from the use of an existing vehicle, since it would have lower development costs, a proven track record, and would benefit from a higher flight rate. The NASA study group that selected what would become the Ares I concluded the opposite, however, and rated the vehicle as almost twice as safe as an Atlas or Delta-derived design.[18]
The NASA study concluded that the cost and safety of the Ares was superior to that of either of the Evolved Expendable Launch Vehicle (EELVs). However the cost estimates in Exploration Systems Architecture Study (ESAS) were based on the assumption that the EELVs would have to be launched from the Shuttle pad at Launch Complex 39, and that the Vehicle Assembly Building, Mobile Launcher Platforms, and LC-39 would have to be modified for the EELVs.[citation needed] However facilities already exist for servicing and launching the EELVs at LC-37 (Delta IV) and LC-41 (Atlas V), which could be modified to accommodate crew boarding and would not have interfered with Shuttle operations. The ESAS launch safety estimates for the Ares were based on the Space Shuttle, despite major differences, but included only launches after Challenger, and counted each of the remaining launches as two safe launches of the Ares booster. The safety of the Atlas V and Delta IV was estimated from the failure rates of all Delta II, Atlas Centaur, and Titan launches since 1992, although they are not similar designs. This meant, for example, that the relatively high failure rate of the Titan IV, which used strap-on solid rocket motors, did not count against the Ares, which has a main solid rocket motor, but counted against the Delta IV-H, which has only liquid propulsion.[citation needed] In May 2009 the previously-withheld appendices to the 2006 ESAS study were leaked, revealing a number of apparent flaws in the study, which gave safety exemptions to the selected Ares I design while using a faulty model which unfairly penalized the EELV-based designs.[19][20]
Delays in the Ares I development schedule due to budgetary pressures and unforeseen engineering and technical difficulties have increased the gap between the end of the Space Shuttle program and the first operational flight of Ares I. As of late 2007[update], the first operational Ares I flight is scheduled for 2015, five years after the last Shuttle flight.[21][22] The total estimated cost to develop the Ares I through 2015 has risen from $28 billion in 2006 to more than $40 billion in 2009.[23]
[edit] See also
- Ares IV
- Ares I-X
- Boilerplate (rocketry)
- Saturn V
- DIRECT, shuttle-derived launcher proposed as alternative to Ares I and Ares V.
[edit] References
- ^ a b "NASA - Ares I Crew Launch Vehicle". NASA. 29 April 2009. http://www.nasa.gov/mission_pages/constellation/ares/aresl/index.html. Retrieved on 13 May 2009.
- ^ "Constellation Program: America’s Fleet of Next-Generation Launch Vehicles, The Ares l Crew Launch Vehicle" (PDF). NASA. November 2008. http://www.nasa.gov/pdf/187391main_aresI_fs_nov08.pdf. Retrieved on 10 January 2009.
- ^ "NASA Awards Upper Stage Engine Contract for Ares Rockets". NASA. 2007-07-16. http://www.nasa.gov/home/hqnews/2007/jul/HQ_C07030_J2X_Contract_prt.htm.
- ^ "Ares I Upper Stage change - receives additional capacity". NASASpaceflight.com. http://www.nasaspaceflight.com/2007/02/ares-i-upper-stage-change-receives-additional-capacity/.
- ^ Lockheed Martin (July 1995). "Technical Area 2 Heavy Lift Launch Vehicle Development Final Report" (PDF). NASA. pp. 3-17, 3-18. http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19960028972_1996058483.pdf.
- ^ "Exploration Systems Architecture Study – Final Report". NASA. http://www.nasa.gov/mission_pages/exploration/news/ESAS_report.html. Retrieved on 2007-01-08.
- ^ Bergin, Chris. "ATK win CLV contract". nasaspaceflight.com, December 7, 2005.
- ^ "NASA’s Ares I First Stage, Powering the Ares I Rocket for liftoff". NASA. Retrieved on 21 April 2009.
- ^ a b NASA (2007-01-04). NASA Completes Review Milestone for Ares I Vehicle. Press release. http://www.nasa.gov/mission_pages/constellation/ares/07-002.html. Retrieved on 2007-01-07.
- ^ NASA Selects Prime Contractor For Ares I Rocket Avionics, NASA, December 12, 2007.
- ^ Connolly, John (2006-10). "Constellation Program Overview" (PDF). NASA. http://www.nasa.gov/pdf/163092main_constellation_program_overview.pdf. Retrieved on 2007-01-08.
- ^ Stein, Keith (2007-01-04). "Draft Launch Schedule For Ares Launch Vehicle". Launchspace.com. http://launchspace.com/articles/ares1407.shtml. Retrieved on 2007-01-08.[dead link]
- ^ Carreau, Mark. "Severe vibration problem plagues moon rocket design", Houston Chronicle, January 19, 2008.
- ^ Borenstein, Seth (2008-01-18). "NASA's Next Rocket May Shake Too Much". Associated Press. http://www.space.com/news/080118-nasa-new-rocket-shake.html. Retrieved on 2008-10-28.
- ^ Carreau, Mark (2008-01-19). "Severe vibration problem plagues moon rocket design". Houston Chronicle. http://www.chron.com/disp/story.mpl/front/5467711.html. Retrieved on 2008-01-20.
- ^ Cowing, Keith (2008-01-17). "NASA's Exploration Systems Mission Directorate Responds to Ares 1 and Orion Questions". NASA Watch. http://www.spaceref.com/news/viewnews.html?id=1266. Retrieved on 2008-01-20.
- ^ NASA Ares Iginiter Tests
- ^ "Part 6 of the Exploration Systems Architecture Study Final Report" (PDF). NASA. http://www.nasa.gov/pdf/140637main_ESAS_06.pdf. Retrieved on 2007-01-10.
- ^ "To the moon and beyond: NASA's Exploration Systems Architecture Study". wikileaks.com. http://wikileaks.org/wiki/To_the_moon_and_beyond:_NASA's_Exploration_Systems_Architecture_Study,_630_pages,_2006. Retrieved on 2009-05-29.
- ^ "More thoughts on ESAS appendix flaws". selenianboondocks.com. http://selenianboondocks.com/2009/05/more-thoughts-on-esas-appendix-flaws/. Retrieved on 2009-05-29.
- ^ "First Stage Design Problems Arise For NASA's Ares 1 Rocket". SpaceRef.com. 2007-11-16. http://www.spaceref.com/news/viewnews.html?id=1244.
- ^ "NASA To Evaluate Non-recoverable First Stage for Ares I Launch Vehicle". SpaceRef.com. 2006-12-04. http://www.spaceref.com/news/viewnews.html?id=1177.
- ^ "Obama plans to order full review of NASA's Ares I, Orion plans". Orlando Sentinel. May 6, 2009. http://www.orlandosentinel.com/orl-shuttle-replacement-under-review-050609,0,7058533.story.
[edit] External links
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Wikimedia Commons has media related to: Project Constellation |
- NASA Ares I page
- NASA Ares I-X (flight test prototype) page
- Ares I GAO Report to Congress
- "NASA Study Finds Human-rated Delta IV Cheaper". Aviation Week
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