Introduction

In the world of aerospace, two major players stand out when it comes to reusable rocket technologies: Blue Origin and SpaceX. Both companies have achieved remarkable milestones in the realm of vertical rocket landings, each with its unique approach and challenges. This article delves into a detailed comparison of Blue Origin's New Shepard Vertical Landing and SpaceX's Falcon 9 Vertical Landing, exploring their technical implementations and the feats of engineering involved.

Background

Rocket engines like the BE-3 used on Blue Origin's New Shepard and Merlin 1D used on SpaceX's Falcon 9 have a unique feature: they can be throttled. This means their thrust can be varied from full to a lower value. For the BE-3, this capability allows it to reduce thrust to about 18% of its full thrust, while the Merlin engine can be throttled down to 70% of its full thrust.

Approach for Landing

Both rocket systems face challenges in negotiating the upper atmosphere due to their trajectories, velocity, size, and weight. Once the rockets have cleared the upper atmosphere, they begin their descent toward the landing site. Interestingly, instead of initiating the landing burn at a higher altitude with a controlled approach, both rockets are designed to reach a significant drop velocity close to the surface. This strategy uses less fuel compared to maintaining a controlled approach throughout the descent.

The rockets perform this maneuver by igniting their engines a few thousand feet above the surface, allowing them to decelerate rapidly to a near-zero vertical velocity. This approach reflects a balance between fuel efficiency and the complexity of the landing sequence.

Landing Mechanism

Blue Origin's New Shepard: The BE-3 engine's deep throttle capability allows a thrust-to-weight ratio of 1, enabling the New Shepard to hover just above the surface, reducing its vertical velocity to near zero and touching down gently.

SpaceX's Falcon 9: In contrast, the Falcon 9's approach is more challenging due to the lower thrust-to-weight ratio even with a single engine at 70% throttle. This machinery produces a thrust-to-weight ratio less than one, making it impossible to hover and requiring precise timing for the landing burn to prevent the rocket from rebounding off the surface.

The precision required for Falcon 9's landing burn is critical. If the rocket reaches zero velocity a few meters above the surface, it must be timed precisely to land without rebounding. This is a much more controlled and technically demanding maneuver compared to the New Shepard's hover landing.

Comparison of Landing Videos

The differences in the landing processes of Blue Origin's New Shepard and SpaceX’s Falcon 9 are most evident when comparing the landing videos. The New Shepard hovers for a few seconds before touchdown, showcasing its ability to maintain a near-zero vertical velocity, whereas the Falcon 9 keeps falling until the moment of touchdown.

This analysis reveals that while both companies achieve successful vertical landings, the engineering challenges and control aspects of Falcon 9's landing are significantly more complex. The hover capability of the New Shepard underscores the efficiency and design advantages of its engine, but the precise landing burns of the Falcon 9 highlight the advanced control systems and engineering feats required for its operation.

Conclusion

In summary, while both Blue Origin and SpaceX have made remarkable strides in vertical rocket landing technology, the specific engineering solutions they employ differ. The hover landing of New Shepard showcases fuel efficiency and design simplicity, whereas Falcon 9's controlled descent emphasizes advanced control engineering and precision timing.