太空發射系統(英語:Space Launch System,簡稱「SLS」)是NASA自2011年以来开发的一种基於太空梭技術的重型運載火箭。SLS火箭目前的主要用途是搭載獵戶座太空船進行阿提米絲計畫,火箭将从位于佛罗里达州的肯尼迪航天中心的LC-39B发射台發射升空。在前四次阿耳忒弥斯任务之后,美国宇航局计划将太空发射系统的生产和发射移交给深空运输公司(Deep Space Transport LLC),这是波音和诺斯洛普·格鲁门的合资企业[17]。不過,预计至少在2030年之前,阿耳忒弥斯计划每年最多使用一次SLS[18]。
太空發射系統Blocks 1和Blocks 1B型使用的五段式固体火箭助推器由于库存限制只能支持八次发射。[50] 于是在2019年3月2日提出了助推器报废和延长寿命计划(BOLE)。该计划是由诺斯洛普·格鲁门开发制造新型的固体火箭助推器,用以支持之后的Blocks 2型太空發射系統。这些助推器源自已经取消的OmegA运载火箭的复合外壳固体火箭助推器,助推器性能的提升可使Blocks 2型的近地轨道有效载荷增加到130 t(130 long ton;140 short ton)地月转移轨道有效载荷增加到46 t(45 long ton;51 short ton)。[51][52][53] 截至2021年7月 (2021-07)[update], BOLE正在大力发展, 预计将于2024年首次点火测试。[51]
上面级
临时低温推进上级(ICPS)将在太空發射系統Block 1型的前三次阿耳忒弥斯登月计划发射中使用。[54] ICPS源自拉长的德尔塔-4运载火箭上面级,由一台RL10火箭发动机提供动力。用于发射的第一个ICPS将使用RL10 B-2型变体, 第二和第三个ICPS将使用 RL10 C-2型变体。[55][56][57] Block 1型能够拥有95 t(93 long ton;105 short ton)的近地轨道运载能力,包括作为有效载荷一部分的ICPS重量。[4] 在阿耳忒弥斯1号任务中,当火箭的核心级分离后,有效载荷将处在1,806乘30 km(1,122乘19 mi) 的亚轨道上,这便于核心级的安全处置。[58] 然后ICPS将执行轨道注入和随后的地月转移,把猎户座飞船送往月球。[59] ICPS将为阿耳忒弥斯2、3号的载人飞行提供乘员认证。[54]
Liquid hydrogen tank for Artemis 2 under construction, as of August 2020"Boat-tail" for Artemis 2 under construction, as of June 2021Engine section shroud structure for Artemis 3 under construction, as of April 2021
In mid-November 2014, construction of the first Core Stage hardware began using a new welding system in the South Vertical Assembly Building at NASA's Michoud Assembly Facility.[154] Between 2015 and 2017, NASA test fired RS-25 engines in preparation for use on SLS.[43]
The core stage for the first SLS, built at Michoud Assembly Facility by Boeing,[155] had all four engines attached in November 2019,[156] and it was declared finished by NASA in December 2019.[157]
The first core stage left Michoud Assembly Facility for comprehensive testing at Stennis Space Center in January 2020.[158] The static firing test program at Stennis Space Center, known as the Green Run, operated all the core stage systems simultaneously for the first time.[159][160] Test 7 (of 8), the wet dress rehearsal, was carried out in December 2020 and the fire (test 8) took place on 16 January 2021, but shut down earlier than expected,[161] about 67 seconds in total rather than the desired eight minutes. The reason for the early shutdown was later reported to be because of conservative test commit criteria on the thrust vector control system, specific only for ground testing and not for flight. If this scenario occurred during a flight, the rocket would have continued to fly normally. There was no sign of damage to the core stage or the engines, contrary to initial concerns.[162] The second fire test was completed on 18 March 2021, with all 4 engines igniting, throttling down as expected to simulate in-flight conditions, and gimballing profiles. The core stage was shipped to Kennedy Space Center to be mated with the rest of the rocket for Artemis 1. It left Stennis on April 24 and arrived at Kennedy on April 27.[163] It was refurbished there in preparation for stacking.[164] On 12 June 2021, NASA announced the assembly of the first SLS rocket was completed at the Kennedy Space Center. The assembled SLS is planned to be used for the uncrewed Artemis 1 mission in 2022.[165]
While the first SLS for Artemis 1 is being prepared for launch, NASA and Boeing are constructing the next three, for Artemis 2, Artemis 3, and Artemis 4.[166] Boeing stated in July 2021 that while the COVID-19 pandemic has affected their suppliers and schedules, such as delaying parts needed for hydraulics, they still will be able to provide the Artemis 2 SLS Core stage per NASA's schedule, with months to spare.[166] The spray-on foam insulation process for Artemis 2 has been automated since Artemis 1 for most sections of the core stage, saving 12 days in the schedule.[167][166] The Artemis 2 forward skirt, which is the foremost component of the Core stage, was affixed on the liquid oxygen tank in late May 2021.[166] 截至2022年7月 (2022-07)[update], is set to ship to NASA in March 2023.[168] Artemis 3, assembly elements of the thrust structure began at Michoud Assembly Facility in early 2021.[166] The liquid hydrogen tank that is to be used on Artemis 3 was originally planned to be the Artemis 1 tank, but it was set aside as the welds were found to be faulty.[169]:2 Repair techniques were developed, and the tank has reentered production and will be proof tested for strength, for use on Artemis 3.[169]:2
Originally planned for late 2016, the uncrewed first flight of SLS has slipped more than sixteen times and more than five years.[註 2] As of July 2022, NASA projects the SLS will launch no earlier than 29 August 2022.[192] NASA limits the amount of time the solid rocket boosters can remain stacked to "about a year" from the time two segments are joined.[193] The first and second segments of the Artemis 1 boosters were joined on 7 January 2021.[194] NASA can choose to extend the time limit based on an engineering review.[195] On 29 September 2021, Northrop Grumman indicated that the limit can be extended to eighteen months for Artemis 1, based on an analysis of the data collected when the boosters were being stacked.[165] In late 2015, the SLS program was stated to have a 70% confidence level for the first Orion flight that carries crew, the second SLS flight overall, by 2023;[196][197][198] 截至November 2021年 (November 2021-Missing required parameter 1=month!)[update], NASA delayed Artemis 2 from 2023[199] to May 2024.[200]Template:SLS launches/future
In 2011, Rep. Tom McClintock and other groups called on the Government Accountability Office to investigate possible violations of the Competition in Contracting Act, arguing that Congressional mandates forcing NASA to use Space Shuttle components for the SLS are de facto non-competitive, single-source requirements assuring contracts to existing Shuttle suppliers.[215][216][217] The Competitive Space Task Force, in September 2011, said that the new government launcher directly violates NASA's charter, the Space Act, and the 1998 Commercial Space Act requirements for NASA to pursue the "fullest possible engagement of commercial providers" and to "seek and encourage, to the maximum extent possible, the fullest commercial use of space".[218][217] Opponents of the heavy launch vehicle have critically used the name "Senate launch system",[56][217][219]a name that was still being used by opponents to criticize the program in 2021, as "the NASA Inspector General said the total cost of the rocket would reach $27 billion through 2025".[220]
Lori Garver, a former NASA Deputy Administrator, called for canceling the launch vehicle alongside the Mars 2020 rover.[221]Phil Plait shared his criticism of the SLS in light of ongoing budget tradeoffs between the Commercial Crew Development and SLS budgets, also referring to earlier critiques by Garver.[222] In 2019, the Government Accountability Office found that NASA had awarded Boeing over $200 million for service with ratings of good to excellent despite cost overruns and delays. 截至2019年 (2019-Missing required parameter 1=month!)[update], the maiden launch of the SLS was expected in 2021.[223][224] NASA continued to expect that the first orbital launch would be in 2021 as late as May 2021.[182]
Visual from the March 2020 Inspector General report, showing how NASA used accounting to "mask" a cost increase by moving the boosters (which cost $889 million) from the SLS to another cost center, without updating the SLS budget to match[225]:iv,22
NASA moved out $889 million of costs relating to SLS boosters, but did not update the SLS budget to match, a March 2020 Inspector General report found. This kept the budget overrun to 15% by FY 2019.[225]:22 At 30%, NASA would have to notify Congress and stop funding unless Congress reapproves and provides additional funding.[225]:21–23 The Inspector General report found that were it not for this "masking" of cost, the overrun would have been 33% by FY 2019.[225]:iv,23 The GAO separately stated "NASA's current approach for reporting cost growth misrepresents the cost performance of the program".[226]:19–20
On 1 May 2020, NASA awarded a contract extension to Aerojet Rocketdyne to manufacture 18 additional RS-25 engines with associated services for $1.79 billion, bringing the total RS-25 contract value to almost $3.5 billion.[227][44]Ars Technica commented that the average cost of each RS-25 therefore rose to $146 million, so each SLS launch uses $580 million for its four engines. Ars noted that for the cost of just one engine, six more powerful RD-180 engines could be purchased, or nearly an entire Falcon Heavy launch with two-thirds of the SLS lift capacity.[227][228] Former NASA Administrator Charlie Bolden, who oversaw the initial design and development of the SLS, also criticized of the program in an interview with Politico in September 2020. Bolden said that the "SLS will go away ... because at some point commercial entities are going to catch up." Bolden further stated, "They are really going to build a heavy-lift launch vehicle sort of like SLS that they will be able to fly for a much cheaper price than NASA can do SLS. That's just the way it works."[229]
A NASA study that was not publicly released[236][237] and another from the Georgia Institute of Technology showed this option to be possibly cheaper.[238][239] In 2012, the United Launch Alliance also suggested using existing rockets with on-orbit assembly and propellant depots as needed. The lack of competition in the SLS design was highlighted.[240][241][242][219][243] In the summer of 2019, a former ULA employee claimed that Boeing, NASA's prime contractor for SLS, viewed orbital refueling technology as a threat to the SLS and blocked further investment in it.[244] In 2011, Robert Zubrin, founder of Mars Society and Mars Direct, suggested that a heavy lift vehicle could be developed for $5 billion on fixed-price requests for proposal.[245] In 2010, SpaceX's CEO Elon Musk claimed that his company could build a launch vehicle in the 140—150 t(310,000—330,000磅) payload range for $2.5 billion, or $300 million (in 2010 dollars) per launch, not including a potential upper-stage upgrade.[246][247]
^ 1.01.11.21.31.4Berger, Eric. NASA does not deny the "over US$2 billion" cost of a single SLS launch. Ars Technica. 2019-11-08 [2019-11-13]. (原始内容存档于2019-11-11). The White House number appears to include both the "marginal" cost of building a single SLS rocket as well as the "fixed" costs of maintaining a standing army of thousands of employees and hundreds of suppliers across the country. Building a second SLS rocket each year would make the per-unit cost "significantly less"
^Gebhardt, Chris. Eastern Range updates "Drive to 48" launches per year status. NASASpaceFlight.com. 2019-08-15 [2020-01-06]. (原始内容存档于2019-11-30). NASA, on the other hand, will have to add this capability to their SLS rocket, and Mr. Rosati said NASA is tracking that debut for the Artemis 3 mission in 2023.
^ 30.030.130.230.3Public Law 111–267 111th Congress, 42 USC 18322. SEC. 302 (c) (2) 42 USC 18323. SEC. 303 (a) (2)(PDF): 11–12. 2010-10-11 [2020-09-14]. (原始内容存档(PDF)于2020-11-12). 42 USC 18322. SEC. 302 SPACE LAUNCH SYSTEM AS FOLLOW-ON LAUNCH VEHICLE TO THE SPACE SHUTTLE [...] (c) MINIMUM CAPABILITY REQUIREMENTS (1) IN GENERAL — The Space Launch System developed pursuant to subsection (b) shall be designed to have, at a minimum, the following: (A) The initial capability of the core elements, without an upper stage, of lifting payloads weighing between 70 tons and 100 tons into low-Earth orbit in preparation for transit for missions beyond low Earth orbit [...] (2) FLEXIBILITY [...] (Deadline) Developmental work and testing of the core elements and the upper stage should proceed in parallel subject to appro-priations. Priority should be placed on the core elements with the goal for operational capability for the core elements not later than December 31, 2016 [...] 42 USC 18323. SEC. 303 MULTI-PURPOSE CREW VEHICLE (a) INITIATION OF DEVELOPMENT (1) IN GENERAL — The Administrator shall continue the development of a multi-purpose crew vehicle to be available as soon as practicable, and no later than for use with the Space Launch System [...] (2) GOAL FOR OPERATIONAL CAPABILITY. It shall be the goal to achieve full operational capability for the transportation vehicle developed pursuant to this subsection by not later than December 31, 2016. For purposes of meeting such goal, the Administrator may undertake a test of the transportation vehicle at the ISS before that date.
^Harbaugh, Jennifer. NASA, Public Marks Assembly of SLS Stage with Artemis Day. nasa.gov. NASA. 2019-12-09 [2019-12-10]. (原始内容存档于2020-02-06). NASA and the Michoud team will shortly send the first fully assembled, 212-foot-tall core stage [...] 27.6-feet-in-diameter tanks and barrels. 本文含有此來源中屬於公有领域的内容。
^Bill Nelson, Kay Bailey Hutchison, Charles F. Bolden. Future of NASA Space Program. Washington, D.C.: Cspan.org. 2011-09-14 [2022-08-18]. (原始内容存档于2022-08-18).
^NASA FY 2019 Budget Overview(PDF). [2019-06-24]. (原始内容存档(PDF)于2019-12-04). Quote: "Supports launch of the Power and Propulsion Element on a commercial launch vehicle as the first component of the LOP–Gateway, (page 14) 本文含有此來源中屬於公有领域的内容。
^Town Hall with Administrator Bridenstine and NASA's New HEO Associate Administrator Douglas Loverro (YouTube). NASA. 事件发生在 24:58. 2019-12-03 [2021-01-20]. (原始内容存档于2021-10-31). "I do not agree with the US$2 billion number, it is far less than that. I would also say that the number comes way down when you buy more than one or two. And so I think at the end we're going to be, you know, in the US$800 million to US$900 million range – I don't know, honestly. We've recently just begun negotiations on what number three through whatever – we don't have to buy any quite frankly, but we intend to. But we're looking at what we could negotiate to get the best price for the American taxpayper, which is my obligation as the head of NASA". 本文含有此來源中屬於公有领域的内容。
^NASA'S MANAGEMENT OF THE ARTEMIS MISSIONS(PDF). Office of Inspector General (United States). NASA: numbered page 23, PDF page 29. 2021-11-15 [2021-11-15]. (原始内容存档(PDF)于2021-11-15). SLS/Orion Production and Operating Costs Will Average Over $4 Billion Per Launch [...] We project the cost to fly a single SLS/Orion system through at least Artemis IV to be $4.1 billion per launch at a cadence of approximately one mission per year. Building and launching one Orion capsule costs approximately $1 billion, with an additional $300 million for the Service Module supplied by the ESA [...] In addition, we estimate the single-use SLS will cost $2.2 billion to produce, including two rocket stages, two solid rocket boosters, four RS-25 engines, and two stage adapters. Ground systems located at Kennedy where the launches will take place—the Vehicle Assembly Building, Crawler-Transporter, Mobile Launcher 1, Launch Pad, and Launch Control Center—are estimated to cost $568 million per year due to the large support structure that must be maintained. The $4.1 billion total cost represents production of the rocket and the operations needed to launch the SLS/Orion system including materials, labor, facilities, and overhead, but does not include any money spent either on prior development of the system or for next-generation technologies such as the SLS’s Exploration Upper Stage, Orion’s docking system, or Mobile Launcher 2. [...] The cost per launch was calculated as follows: $1 billion for the Orion based on information provided by ESD officials and NASA OIG analysis; $300 million for the ESA’s Service Module based on the value of a barter agreement between ESA and the United States in which ESA provides the service modules in exchange for offsetting its ISS responsibilities; $2.2 billion for the SLS based on program budget submissions and analysis of contracts; and $568 million for EGS costs related to the SLS/Orion launch as provided by ESD officials. 本文含有此來源中屬於公有领域的内容。
^ 225.0225.1225.2225.3NASA'S MANAGEMENT OF SPACE LAUNCH SYSTEM PROGRAM COSTS AND CONTRACTS(PDF). NASA – Office of Inspector General – Office of Audits. 2020-03-10 [2020-09-14]. (原始内容存档(PDF)于2020-08-28). Based on our review of SLS Program cost reporting, we found that the Program exceeded its Agency Baseline Commitment (ABC) by at least 33 percent at the end of FY 2019, a figure that could reach 43 percent or higher if additional delays push the launch date for Artemis I beyond November 2020. This is due to cost increases tied to Artemis I and a December 2017 replan that removed almost $1 billion of costs from the ABC without lowering the baseline, thereby masking the impact of Artemis I’s projected 19-month schedule delay from November 2018 to a June 2020 launch date. Since the replan, the SLS Program now projects the Artemis I launch will be delayed to at least spring 2021 or later. Further, we found NASA’s ABC cost reporting only tracks Artemis I-related activities and not additional expenditures of almost $6 billion through FY 2020 that are not being reported or tracked through the official congressional cost commitment or the ABC. [...] as a result of delaying Artemis I up to 19 months to June 2020, NASA conducted a replan of the SLS Program in 2017 and removed $889 million in Booster and RS-25 Engine-related development costs because SLS Program officials determined those activities were not directly tied to Artemis I. [...] In our judgement, the removal of these costs should have reduced the SLS Program’s ABC development costs from $7.02 billion to $6.13 billion. [...] SLS Program and HEOMD officials disagreed with our assessment and stated the SLS Program’s change in cost estimates for the Booster and Engines element offices were not a removal of costs but rather a reallocation of those activities to appropriately account for them as non-Artemis I costs. [...] Federal law requires that any time Agency program managers have reasonable knowledge that development costs are likely to exceed the ABC by more than 30 percent, they must notify the NASA Administrator. Once the Administrator determines the SLS Program will exceed the development cost baseline by 30 percent or more, NASA is required to notify Congress and rebaseline program costs and schedule commitments. If the Administrator notifies Congress of the need to rebaseline, NASA is required to stop funding program activities within 18 months unless Congress provides approval and additional appropriations. In our judgement, using NASA’s cost estimates from October 2019 and accounting for the removed costs from the replan, the SLS Program was required to rebaseline when the program exceeded its ABC by 33 percent at the end of FY 2019, an increase that could reach 43 percent or higher by the Artemis I launch date. 本文含有此來源中屬於公有领域的内容。
^NASA HUMAN SPACE EXPLORATION: Persistent Delays and Cost Growth Reinforce Concerns over Management of Programs(PDF). GAO. [2020-09-15]. (原始内容存档(PDF)于2021-10-03). NASA’s current approach for reporting cost growth misrepresents the cost performance of the program and thus undermines the usefulness of a baseline as an oversight tool. NASA’s space flight program and project management requirements state that the agency baseline commitment for a program is the basis for the agency’s commitment to the Office of Management and Budget (OMB) and the Congress based on program requirements, cost, schedule, technical content, and an agreed-to joint cost and schedule confidence level. Removing effort that amounts to more than a tenth of a program’s development cost baseline is a change in the commitment to OMB and the Congress and results in a baseline that does not reflect actual effort. [...] Further, the baseline is a key tool against which to measure the cost and schedule performance of a program. A program must be rebaselined and reauthorized by the Congress if the Administrator determines that development costs will increase by more than 30 percent. Accounting for shifted costs, our analysis indicates that NASA has reached 29.0 percent development cost growth for the SLS program. [...] In addition, as we previously reported in May 2014, NASA does not have a cost and schedule baseline for SLS beyond the first flight. As a result, NASA cannot monitor or track costs shifted beyond EM-1 against a baseline. We recommended that NASA establish cost and schedule baselines that address the life cycle of each SLS increment, as well as for any evolved Orion or ground systems capability. NASA partially concurred with the recommendation, but has not taken any action to date. [...] By not adjusting the SLS baseline to account for the reduced scope, NASA will continue to report costs against an inflated baseline, hence underreporting the extent of cost growth. NASA’s Associate Administrator and Chief Financial Officer stated that they understood our rationale for removing these costs from the EM-1 baseline and agreed that not doing so could result in underreporting of cost growth. Further, the Associate Administrator told us that the agency will be relooking at the SLS program’s schedule, baseline, and calculation of cost growth. 本文含有此來源中屬於公有领域的内容。
^Review of U.S. Human Space Flight Plans Committee; Augustine, Austin; Chyba, Kennel; Bejmuk, Crawley; Lyles, Chiao; Greason, Ride. Seeking A Human Spaceflight Program Worthy of A Great Nation(PDF). NASA. October 2009 [2010-04-15]. (原始内容存档(PDF)于2019-02-16). 本文含有此來源中屬於公有领域的内容。