SpaceX vs. the Space Launch System: Why Does NASA Still Fly a Rocket the Industry Calls Obsolete?

Key Takeaways

• The SLS is nicknamed the “Senate Launch System” due to its origins in congressional job preservation politics after the Space Shuttle’s retirement
• SLS prime contractors operate across all 50 U.S. states, generating roughly 69,000 jobs and creating near-universal congressional protection for the program
• SpaceX developed Falcon 9 for an estimated $443 million; a NASA analysis found its traditional procurement approach would have cost $1.4 billion for the same rocket

Origins in the Chamber, Not the Engineering Lab

Long before the first Space Launch System rocket rolled to Launch Complex 39B, the nickname had already attached itself permanently: the Senate Launch System. It arrived not as an insult invented by SpaceX fans but as an observation from people who had watched the program’s creation closely. The NASA Authorization Act of 2010 directed NASA to build a new heavy-lift vehicle capable of sending crew beyond Earth orbit, using existing shuttle and Constellation program infrastructure “to the extent possible.” The phrase “to the extent possible” was not an engineering requirement. It was a political instruction, written to protect the jobs and contractors associated with the Space Shuttle program, which had just been retired.

Senators from Alabama, home to NASA’s Marshall Space Flight Center in Huntsville; Texas, home to the Johnson Space Center in Houston; and Florida, home to Kennedy Space Center, led the push for the SLS design. They were not primarily concerned with which launch architecture would most efficiently return humans to the Moon. They were concerned with what would happen to tens of thousands of aerospace workers and contractors after the shuttle fleet flew its last mission in July 2011.

Former astronaut Terry Virts framed the mechanism directly: “You can blame George Washington and Benjamin Franklin and Thomas Jefferson. When they made the Constitution, they made these things called congressional districts. And the goal of Congress is to bring home the bacon for their districts.” The SLS is, in its political economy, an exercise in what scholars of public policy call distributive politics: spreading government spending widely enough that legislators from most districts have a direct financial stake in its continuation.

The Job Map

Boeing is the prime contractor for the SLS core stage, operating out of NASA’s Michoud Assembly Facility in Louisiana, approximately 10 miles from New Orleans. Northrop Grumman builds the solid rocket boosters at facilities in Utah. Aerojet Rocketdyne manufactures the RS-25 main engines, four of which power each SLS core stage, with engine testing conducted at the Stennis Space Center in Mississippi. Lockheed Martin builds the Orion crew capsule at the same Michoud facility. Assembly, integration, and launch operations occur at Kennedy Space Center in Florida.

Each of those geographic anchors is attached to a senator or representative who has strong incentives to protect the program. The Planetary Society documented the full extent of the program’s geographic reach: the SLS and Orion programs together involve more than 3,800 suppliers spread across all 50 states and Puerto Rico, generating approximately $14 billion in total economic output and supporting more than 69,000 jobs, according to a 2019 economic impact assessment. Those numbers represent not just a major employer but a distributed political coalition. A senator from Montana who would otherwise have no reason to care about launch vehicle architecture may find that a local machine shop or electronics supplier has a contract with Boeing’s Michoud operation. That creates a reason to care.

The political durability that flows from this geography has been demonstrated repeatedly. Every administration since the SLS’s creation has, at various points, questioned its costs or architecture. None has successfully canceled it. The SLS’s budget has grown and received congressional protection under two Democratic and two Republican presidencies. In July 2025, analysis from City Journal concluded that despite the most reform-minded NASA leadership in the program’s history, “Capitol Hill’s perennial addiction to NASA pork” had once again blocked meaningful change.

What the Program Cost to Build

Development of the SLS from its formal inception to its first launch in November 2022 cost approximately $11.8 billion for the initial Block 1 capability. That figure does not include the separately tracked $412 million contract for the Interim Cryogenic Propulsion Stage, the upper stage used for Artemis I and Artemis II, or the approximately $600 million per year that NASA spends on Exploration Ground Systems, the launch processing infrastructure at Kennedy Space Center. The Orion crew capsule, developed by Lockheed Martin, carries its own development cost history that began with the canceled Constellation program and has continued accumulating since.

The Government Accountability Office noted in its 2023 report that without a mission-by-mission cost baseline for production and operations, meaningful oversight of whether the program was becoming more or less affordable over time was essentially impossible. NASA created a rolling five-year estimate to track costs within its budget, but that tool, GAO found, is “a poor measure of cost performance over time.” Senior NASA officials had directly told GAO that the SLS was unaffordable at current cost levels.

The Trump administration’s fiscal year 2026 budget proposal, released in May 2025, described the rocket as 140% over its original budget and “grossly expensive” at approximately $4 billion per launch. The Cato Institute, the Reason Foundation, and the Citizens Against Government Waste have independently characterized the program’s cost trajectory as indefensible by market standards. These are not politically aligned critics. They span the ideological range of organizations that examine government spending.

The Cost-Plus Problem

Understanding why SLS costs so much requires understanding how its contracts are structured. Under cost-plus arrangements, NASA agrees to reimburse contractors for all project costs and then adds a fee representing profit. If costs rise beyond original projections due to delays, design changes, or management failures, the government covers those additional expenses. The contractor earns a fee regardless. This structure removes the financial discipline that fixed-price contracts impose in competitive commercial markets.

Laura Seward Forczyk, founder of the Atlanta-based space consulting firm Astralytical, articulated the structural problem clearly: “NASA is going to continually get that money from Congress, and so there’s no incentive for these companies to change direction, change management or change the way they’re doing things.” The SLS’s development history confirms her analysis. Boeing received approximately $234 million of a possible $262 million in available award fees between fiscal years 2013 and 2017, a period during which the program accumulated significant schedule delays and cost overruns that a 2018 NASA Inspector General report attributed to poor oversight and questionable contract management by both Boeing and NASA.

In February 2025, Boeing informed its SLS-related employees that they faced potential layoffs when the company’s contract expired in March. The announcement coincided with the anticipated White House budget proposal and signaled that the political protection the program had enjoyed was being tested in a new way. Boeing itself was dealing with broader corporate turbulence in this period, having faced multiple aircraft certification crises that strained its finances and management attention.

What SpaceX Built for Less

The contrast with SpaceX‘s development methodology is quantifiable in ways that make direct comparison unavoidable.

NASA commissioned an analysis of what it would have cost to develop Falcon 9 using its traditional procurement approach versus what SpaceX actually spent. The traditional approach was estimated at approximately $1.4 billion. SpaceX’s actual development cost was approximately $443 million, less than a third of the traditional figure. Falcon 9 then went on to become the most commercially successful orbital rocket in history, capturing an estimated 65% of the global commercial launch market and executing hundreds of successful missions across satellite deployment, cargo resupply to the International Space Station, and crewed flights under NASA’s Commercial Crew program.

The cost comparison becomes more striking when operational costs are included. A Falcon Heavy launch, capable of sending approximately 26.7 tons to a translunar trajectory, costs in the range of $90 million to $150 million per flight. The SLS Block 1, with a similar translunar payload capacity in its crewed configuration, costs an estimated $4.1 billion per flight. Even granting generous adjustments for differences in how the figures are calculated and what costs are included, the gap is extraordinary.

Starship represents the most direct technical challenge to the SLS’s rationale. SpaceX’s fully reusable heavy-lift system is designed to deliver more than 100 tons to low Earth orbit, substantially exceeding SLS’s payload capacity, and to do so with both stages recovered and reflown, eliminating the manufacturing cost of new hardware for each mission. Current estimates place the cost of a Starship launch at roughly $100 million in its initial operational period, with SpaceX CEO Elon Musk projecting costs below $10 million as full reusability matures. Independent analysts treat the $10 million figure as aspirational, but the fundamental economics of reusability are already demonstrated at commercial scale by the Falcon 9’s booster recovery program.

The SLS, by contrast, is fully expendable. Every launch consumes a new core stage, new solid rocket boosters, and a new upper stage. The RS-25 main engines on each core stage are shuttle-era hardware that costs tens of millions of dollars each and is destroyed on every flight. The Orion capsule is recovered after splashdown and could theoretically be reflown, but the rocket that launched it is lost.

The Europa Clipper Precedent

One of the clearest demonstrations of what the SLS’s political protection costs came with the Europa Clipper mission, NASA’s flagship probe to Jupiter’s moon Europa. Congress initially mandated by statute that the probe fly on the SLS, a directive that had nothing to do with technical necessity and everything to do with providing the SLS manifest with a high-profile mission to justify its production schedule. When NASA eventually sought and received congressional approval to competitively bid the launch contract, SpaceX won with a Falcon Heavy at a price that the agency estimated saved approximately $2 billion compared with what an SLS launch would have cost.

That $2 billion saving came from a single mission launch contract. It represents real money that is now available for science rather than launch vehicle overhead. The Europa Clipper precedent is frequently cited by SLS critics as evidence that commercial alternatives can provide equivalent capability at dramatically lower cost when the political requirement to use SLS is removed.

The pattern of mandatory SLS manifesting has also shaped the broader program’s architecture in ways that constrain efficiency. Northrop Grumman received a $3.2 billion contract under the Booster Obsolescence and Life Extension program to develop new solid rocket boosters for the SLS, replacing shuttle-era hardware for Artemis missions IV through VIII. Each of those new boosters is designed to produce approximately 3.9 million pounds of thrust. Whether that investment represents sound resource allocation, given the trajectory of commercial heavy-lift capability, is a question the SLS’s own program office does not engage with directly.

The Administrator’s Uncomfortable Admission

NASA Administrator Jared Isaacman delivered one of the clearest public signals yet from a senior U.S. space official that the Space Launch System is not intended to be NASA’s long-term transportation system for deep-space exploration. Testifying before the Senate Committee on Commerce, Science, and Transportation during his April 9, 2025 confirmation hearing, he said SLS was not “the long-term way to get to and from the Moon, and to Mars, with great frequency.” He also indicated that NASA should use the current architecture to fly the crewed lunar missions already in plan – saying “this is the plan we have now” and referring to getting “this crew around the moon and the follow-on crew to land on the moon” – before eventually shifting toward more capable commercial heavy-lift launch options for sustained lunar and Mars transportation.

That position aligned with the White House’s fiscal year 2026 budget proposal, which called for ending SLS and Orion production after Artemis III and redirecting an estimated $879 million in savings toward commercial alternatives. For a brief period in mid-2025, it appeared that the executive branch, the NASA administrator, and the space industry reform community were aligned on a clear path toward commercial transition.

Congress moved in the opposite direction. The 2025 “One Big Beautiful Bill Act” included $4.1 billion to fund SLS rockets for Artemis IV and Artemis V, with mandated minimum annual spending of $1.025 billion from fiscal year 2026 through fiscal year 2029. Lawmakers included a provision directing NASA to evaluate alternatives to the SLS’s planned Exploration Upper Stage, and in February 2026, Isaacman announced the cancellation of the Exploration Upper Stage, directing the agency to use ULA‘s Centaur V. But the SLS program’s core survival was guaranteed by legislative action.

The asymmetry between what Isaacman said SLS should be and what Congress legislated it to be is the defining contradiction of current U.S. launch policy. It will not resolve quickly, and it will not resolve in favor of either side without political changes that have not yet materialized.

The Commercial Crew Comparison

The argument that commercial launch vehicles cannot be trusted for human spaceflight to deep space was more credible before the Commercial Crew program began delivering results. SpaceX’s Crew Dragon has now transported American astronauts to and from the International Space Station on multiple operational missions. The Crew-1 mission in November 2020, the first operational Commercial Crew flight, carried Victor Glover, who is now scheduled to fly on Artemis II, aboard the SpaceX vehicle. The notion that commercial spacecraft cannot safely carry human beings to space is no longer available as an argument.

The more legitimate concern is certification for deep space, specifically the radiation environment and mission duration beyond low Earth orbit. Crew Dragon has not flown beyond Earth’s protective magnetic field. The Orion capsule has been specifically designed and certified for the deep-space environment, with radiation shielding and life support capacity appropriate for multi-day cislunar missions. That certification gap is real, and closing it for a commercial deep-space vehicle would require significant investment and testing.

Whether investing that money in commercial deep-space certification would ultimately cost less than continuing SLS is a calculation that has not been done publicly with adequate rigor. The path Isaacman proposed, use what’s already built and then transition, represents a reasonable approach that acknowledges sunk costs without committing to them indefinitely. Whether it survives the political momentum that will follow a successful Artemis III mission is, at this moment, genuinely uncertain. Programs that deliver visible success tend to find new congressional champions.

Where the SLS Goes After Artemis V

NASA has announced plans to transfer production and launch operations of the SLS to Deep Space Transport LLC, a joint venture between Boeing and Northrop Grumman, following Artemis IV. The stated goal is to place SLS on a commercial launch services contract, allowing the private venture to seek non-NASA customers and potentially drive costs toward $1 billion per flight. The optimistic scenario envisions the joint venture finding a market large enough to support a production cadence that improves unit economics.

The realistic assessment of that prospect is considerably more cautious. The commercial market for payloads that justify a super-heavy-lift launcher is limited. The payloads that genuinely need SLS-class lift capacity are, in most cases, government missions that could, with architectural flexibility, be broken into multiple launches on smaller vehicles. Without a robust commercial manifest independent of NASA, the economics of achieving $1 billion per flight are mathematically difficult. The SLS program’s own documentation acknowledges that finding a market for the rocket after NASA transitions away will be “difficult.”

The most likely trajectory for the SLS, barring a significant change in commercial space development or U.S. space policy, is a gradual decline in mission cadence following Artemis V, a diminishing political coalition as the shuttle-era workforce retires and contracts wind down, and eventual operational termination sometime in the 2030s. Whether that termination comes before or after commercial alternatives demonstrate deep-space human certification will be the key factor in how the transition is managed.

Summary

The SLS survives not because independent analysis supports its cost structure or its engineering rationale over commercial alternatives, but because it embeds federal spending in a geographic pattern that makes cancellation politically prohibitive. That is not a trivial consideration: political sustainability is a genuine prerequisite for any exploration program requiring decadal commitment. It is also not a sufficient justification for a rocket that the White House, the NASA administrator, the Government Accountability Office, and NASA’s own Inspector General have all described as unaffordable. Artemis II will fly on it. The two missions that follow will fly on it. What happens after that depends on whether the political coalition that has protected the program since 2010 holds when commercial alternatives are mature enough to offer a compelling credible transition.

Appendix: Top 10 Questions Answered in This Article

Why is the Space Launch System called the “Senate Launch System”?

The nickname reflects the program’s origins in congressional politics rather than engineering requirements. Senators from Alabama, Texas, and Florida pushed for the SLS to preserve shuttle-era jobs after the Space Shuttle’s retirement in 2011. The NASA Authorization Act of 2010 directed the agency to use existing shuttle infrastructure “to the extent possible,” embedding political priorities in the rocket’s design specifications.

How much does the Space Launch System cost per launch?

NASA’s Office of Inspector General estimated in 2021 that each SLS and Orion launch costs approximately $4.1 billion in operating costs alone. The Trump administration’s fiscal year 2026 budget proposal described the per-launch cost as approximately $4 billion and noted the program was 140% over its original budget.

Why doesn’t NASA just use SpaceX rockets instead of SLS?

Congress legislated mandatory SLS funding through the “One Big Beautiful Bill Act” of 2025, which included $4.1 billion for Artemis IV and V rockets with minimum annual spending requirements. The SLS program supports jobs across all 50 states and Puerto Rico, and eliminating it would require a congressional majority willing to vote against employment in their own districts.

What did NASA Administrator Jared Isaacman say about SLS’s future?

Isaacman testified in his Senate confirmation hearing that the SLS was not “the long-term way to get to and from the moon and Mars with great frequency.” He proposed completing Artemis II and III with existing SLS hardware and then transitioning to commercial launch providers, a position the White House’s fiscal year 2026 budget supported but Congress overrode.

How much did SpaceX spend developing Falcon 9 compared to NASA’s traditional approach?

SpaceX developed Falcon 9 for an estimated $443 million. A NASA analysis estimated the agency’s traditional cost-plus procurement approach would have cost approximately $1.4 billion to develop the same rocket. This comparison is among the most frequently cited data points in arguments for commercial launch procurement reform.

What happens to SLS after Artemis V?

After Artemis IV, NASA plans to transfer SLS production and launch operations to Deep Space Transport LLC, a joint venture between Boeing and Northrop Grumman. The agency hopes the venture can attract commercial customers and reduce per-launch costs toward $1 billion, though analysts have described finding a commercial market for the rocket as difficult.

How does Starship compare to SLS in cost and capability?

SLS Block 1 delivers approximately 27 tons to translunar injection at an estimated $4.1 billion per flight. Starship is designed to exceed 100 tons to low Earth orbit with full reusability, at a current per-launch cost estimated around $100 million. Starship requires orbital refueling for crewed lunar missions, adding operational complexity that SLS’s direct-injection architecture avoids.

Was the Europa Clipper supposed to fly on SLS?

Yes. Congress initially mandated by statute that the Europa Clipper fly on the SLS. NASA later received approval to competitively bid the launch, and SpaceX won the contract with a Falcon Heavy. NASA estimated the commercial launch saved approximately $2 billion compared with what an SLS flight would have cost.

Why did Boeing receive award fees despite SLS delays?

Under cost-plus contracting, Boeing received approximately $234 million of a possible $262 million in award fees between fiscal years 2013 and 2017, despite significant schedule delays and cost overruns. A 2018 NASA Inspector General report criticized the agency for rating Boeing’s performance as “very good to excellent” during years of documented program problems.

How many times has SLS’s launch schedule slipped?

The SLS program’s first launch, originally planned for December 2016, flew in November 2022, a delay of nearly six years, with the date slipping more than 26 times. Artemis II was originally scheduled for November 2024, moved to September 2025, then to early 2026, with additional scrubs in February and March 2026 before the April 1 target was set.