SLS Rocket: Congress Seeks Cost-Effective Upper Stage Solution

Congress Pushes Back on NASA‘s Moon Rocket cuts

Lawmakers are signaling their intent to keep the Space Launch System (SLS) program alive, despite white House proposals to curtail its future.

The Trump administration’s plan to cancel the massive Space launch system (SLS) rocket is facing important opposition from Congress. Spending bills moving through both the House and Senate reject the administration’s proposal to end the SLS program after its next two missions.

However,a recent draft budget from the House Appropriations Committee suggests a willingness to consider substantial changes to the program itself.

The upcoming Artemis II mission, slated for early next year, will carry four astronauts on a journey around the far side of the Moon. This flight follows the prosperous unpiloted Artemis I mission in 2022.

The subsequent Artemis III mission aims for a historic crewed lunar landing at the moon’s south pole.These missions represent the current planned trajectory for the SLS.

Following Artemis III, the administration’s official policy is to terminate the SLS and its accompanying Orion crew capsule. The proposal also included canceling the Gateway, a planned mini-space station in lunar orbit.

Rather,NASA woudl rely on commercial launches and spacecraft to transport crews between Earth and the Moon,shifting its long-term focus towards Mars exploration.

Both House and Senate appropriations bills aim to preserve the SLS, Orion, and the Gateway. A notable element in the House version of NASA’s budget, though, directs the agency to investigate more economical and expedited options for a new SLS upper stage.

Boeing,the contractor responsible for SLS core stages,is already developing an Exploration Upper Stage for the Artemis IV mission. This next-generation stage will feature larger propellant tanks and four engines, a significant upgrade from the interim upper stage used for the initial Artemis flights.

What specific cost reduction measures are being considered for the Exploration Upper Stage (EUS) design and manufacturing process?

The Evolving Landscape of SLS Upper Stages

the Space Launch System (SLS) rocket, NASA’s flagship for deep space exploration, is facing renewed scrutiny regarding the cost-effectiveness of its upper stages. While the SLS Block 1 configuration successfully launched the Artemis I mission, congress is actively pushing for solutions to reduce costs associated with future SLS iterations, particularly the Block 1B and Block 2. This focus stems from the significant expense of the current exploration upper Stage (EUS) and the desire to maintain a sustainable lunar and Martian exploration programme.

Understanding the Current SLS Upper stage Options

Currently, the SLS utilizes, or plans to utilize, different upper stages depending on the block configuration:

Interim Cryogenic Propulsion Stage (ICPS): Used on Artemis I, the ICPS is a modified Delta Cryogenic Second Stage. It’s a relatively low-cost option but limited in capability.

Exploration Upper Stage (EUS): Designed for the SLS Block 1B, the EUS offers considerably increased performance, enabling heavier payloads to be sent to the Moon and beyond. Though, its development costs have been a major concern. The EUS is capable of delivering over 45 tons to a translunar orbit.

SLS Block 2 Upper Stage: This future iteration aims for even greater capabilities, perhaps utilizing advanced propulsion technologies.

Congressional Concerns and Cost Drivers

The primary driver behind the congressional push for a cost-effective solution is the escalating price tag of the EUS. Several factors contribute to these high costs:

Limited Competition: The EUS contract was awarded to Boeing, with limited competition during the bidding process.

Complex Engineering: The EUS requires advanced cryogenic propellant management and high-performance engines.

Low Production Volume: The relatively small number of EUS units planned for production increases the per-unit cost.

Schedule Delays: Delays in development and testing have further inflated costs.

Potential Solutions Being Explored

Congress is evaluating several options to address the cost concerns:

1. Competition for Future Upper Stages: Encouraging competition for the Block 2 upper stage contract could drive down prices. This includes exploring options from companies like SpaceX and Blue Origin.
2. Commercial Upper Stage Integration: Utilizing commercially developed upper stages, potentially modified for SLS compatibility, is a key area of investigation. This leverages existing technology and potentially reduces development costs.
3. EUS Cost Reduction Measures: Identifying areas within the EUS design and manufacturing process where costs can be cut without compromising performance. This includes value engineering and streamlining production.
4. Option Propulsion Systems: Investigating alternative propulsion systems for the Block 2 upper stage, such as methalox engines, which may offer cost advantages over traditional cryogenic engines.
5. Modular Upper Stage Design: A modular approach to upper stage design could allow for greater flexibility and cost savings by utilizing common components across different SLS configurations.

The Impact on Artemis Missions and Beyond

The choice of upper stage significantly impacts the scope and cadence of future Artemis missions and long-term space exploration goals. A more affordable upper stage solution would:

increase Mission Frequency: Lower costs would enable more frequent launches, accelerating the pace of lunar and Martian exploration.

Enable Larger Payloads: A higher-performance upper stage allows for the delivery of larger payloads, including habitats, rovers, and scientific instruments.

Improve Program sustainability: Reducing overall program costs enhances the long-term sustainability of NASA’s deep space exploration efforts.

* Facilitate commercial Partnerships: A more cost-effective SLS could attract greater commercial investment and participation in space exploration.

SLS Capabilities Compared to Historical Rockets

The SLS is designed to rival the capabilities of the Saturn V rocket used during the Apollo program. According to sources like Zhihu, the SLS has varying capabilities depending on the version, with a maximum capacity to launch over 45 tons to a translunar orbit. this places it in the same performance class as the Saturn