NASA’s Next Steps in Cislunar and Mars Exploration Post-SLS Cancellation
In its latest “skinny” budget submission, the White House Office of Management and Budget (OMB) once again proposed canceling NASA’s deep-space flagship hardware—the Space Launch System (SLS) rocket, Orion crew capsule, and Lunar Gateway station—after completing Artemis III. While Congress has historically staunchly defended these programs, lawmakers and industry experts now acknowledge that a pivot toward commercially led capabilities may offer the more sustainable path to both the Moon and Mars. Below, we dissect the technical, legislative, and programmatic contours of this potential paradigm shift and explore how NASA’s next decade of exploration could unfold under a commercial model.
Will Congress Let Go of SLS and Orion?
For 15 years the SLS and, for two decades, the Orion spacecraft have enjoyed near‐unanimous bipartisan support in Congress. They have served both as flagship exploration vehicles and as reliable economic engines for key districts. Yet, high per‐launch costs—estimates exceed $2 billion per SLS flight for the Block 1B—and repeated schedule slips have reignited debate about their long-term viability.
During the April confirmation hearing of Jared Isaacman—Trump’s nominee for NASA Administrator—both Republicans and Democrats questioned him about utilizing SLS and Orion for Artemis II and III. He affirmed plans to reach lunar orbit and land before program termination, but kept silent on missions beyond. According to a senior Senate appropriator, “Congressional leaders realize the math simply doesn’t work under current budget forecasts.” With OMB’s impoundment threat looming—an executive tool to withhold appropriated funds—the fight may end up before the Supreme Court, where neither side wants to stake its legacy.
Leadership Realignment and Policy Direction
Traditionally, NASA’s budget priorities have been dictated from Russ Vought’s OMB office, often resulting in abrupt science program terminations. However, the upcoming confirmations of Jared Isaacman as Administrator and the establishment of a revitalized National Space Council led by Vice President J.D. Vance promise to restore policy coherence.
- Isaacman’s commercial space background suggests a shift toward public-private partnerships.
- The National Space Council can elevate strategic directives above pure budgetary considerations.
- OMB will likely collaborate more closely with NASA in drafting a long‐term architecture rather than imposing stop-gaps.
The COTS Model Returns for Artemis IV and Beyond
If SLS and Orion are retired post-Artemis III, NASA would logically resurrect the Commercial Orbital Transportation Services (COTS) approach—used successfully since 2006 to supply the ISS via SpaceX Dragon and Northrop Grumman Cygnus. Under a “Lunar COTS” framework, NASA would:
- Define a technical performance baseline and safety requirements.
- Award milestone-based prizes covering R&D, integration, and operations.
- Contract for end-to-end services: crew transport, lunar descent/ascent, and return.
SpaceX’s Starship system is an obvious lead contender. Tested to deliver 150 metric tons to lunar orbit, Starship can potentially consolidate habitat, ascent, and descent modules into a single reusable vehicle. Blue Origin, in partnership with Lockheed Martin, could evolve its Blue Moon lander and a new crew capsule. Rockets from emerging players like United Launch Alliance’s Vulcan Centaur and Rocket Lab’s Neutron might fill medium-cargo roles.
Technical Assessment: SLS Block 1B vs. Starship
Below is a high-level comparison of key performance metrics:
- Payload to TLI (Trans-Lunar Injection): SLS Block 1B—42 t; Starship—>150 t.
- Launch Cost (approx.): SLS—$2–2.5 billion; Starship (est.)—$50–100 million.
- Reusability: SLS—expendable core + boosters; Starship—fully reusable stages.
- Infrastructure: SLS—requires Mobile Launcher 2 and Launch Pad 39B upgrades; Starship—Starbase launch complex and offshore integration platforms.
Experts like former NASA launch director John Shannon argue, “Transitioning to a commercial heavy-lift provider not only cuts costs by an order of magnitude but also accelerates cadence—critical if NASA is to establish a sustained cislunar presence.”
Legal and Legislative Path Forward
Should appropriators reject the skinny budget’s cuts, OMB may invoke the Impoundment Control Act of 1974 to defer or rescind funding. Legal scholars are split on whether unilateral impoundment of already‐appropriated funds withstands judicial review. Senator Maria Cantwell (D-WA) has signaled intent to block impoundment, stating: “Congress writes the checks; the executive cannot simply decide which bills to pay.” A Supreme Court battle could set a centuries-old precedent on separation of powers.
Deepening the Cislunar Economy
Beyond launch services, NASA’s Commercial Lunar Payload Services (CLPS) program has seeded over a dozen small landers to ferry science onto the Moon. A Lunar COTS expansion would extend this to logistical hubs, in-space refueling depots, and commercial habitats. Economists at the Space Frontier Foundation estimate that a 20-year cislunar logistics network could generate $50 billion in private capital investment and thousands of skilled jobs.
Preparing for Mars: From Cargo to Crew
The Trump OMB proposal earmarked $1 billion in new Mars-focused funding alongside $7 billion for lunar work. While modest by NASA standards, this seed funding could catalyze a Mars COTS program. Initial phases would contract cargo missions—robotic landers delivering 5–10 t of supplies to Mars orbit or surface by 2030. Later phases could integrate life-support modules, ascent vehicles, and crewed transit cabins offered by companies like SpaceX, Rocket Lab, and Impulse Space.
Curtis Marvin, a planetary scientist with the MIT Kavli Institute, notes: “Frequent, low-cost cargo deliveries are the foundation for a sustainable Mars exploration campaign. They democratize access, reduce mission risk via multiple flight opportunities, and accelerate technology maturation.”
Concluding Outlook
If Congress acquiesces to OMB’s Artemis plan, NASA will complete Artemis III atop SLS and Orion before pivoting to a commercially driven architecture. This approach aims to:
- Reduce per-mission costs by up to 80% through reusability and market competition.
- Accelerate mission frequency to both the Moon and Mars.
- Foster a thriving commercial ecosystem in cislunar space and beyond.
While legacy hardware retirement entails political friction, the commercial model holds promise for achieving President Trump’s 2030 Mars landing ambition—and, critically, ensuring that lunar and Martian exploration becomes routine rather than exceptional.