A new study points out that the heavy-lift launch vehicle "Starship" being tested by SpaceX is expected to play a key role in transportation capacity, orbital refueling and acting as an air brake protection body, thereby significantly accelerating the progress of NASA's planned Uranus flagship exploration mission.

Uranus and another "ice giant" have long been considered one of the most worthy of in-depth study in the solar system. The 10-year planetary science planning report released by the National Academy of Sciences in 2022 has listed the "Uranus Orbiter and Probe" (UOP) as the top priority for flagship missions. However, the detailed plan for the launch window in the 2030s has not yet been fully finalized, leaving room for the "intervention" of a new generation of launch technology.

At present, humans' close-range exploration of Uranus is still extremely limited. The last visit was a flyby of Voyager 2 nearly 40 years ago, during which it did not enter orbit. Uranus and Neptune are the only planets in the solar system that have never received a long-term spacecraft. They contain a lot of unknowns in terms of planet formation, internal structure, magnetic field characteristics, and satellite systems. Uranus itself is lying on its side and rotating, and the magnetic field axis is both tilted and deviated from the center of the planet. There may also be underground oceans covered by ice shells in its satellite group. At the same time, planets similar in size and composition to Uranus have become the most common targets in current exoplanet searches. The systematic investigation of Uranus is regarded as an important "sample" for understanding the Earth-like exoplanet system.

The biggest difficulty in Uranus mission planning is the time and cost pressure brought by distance. The average distance to Uranus from the sun is about 19 times that of the Earth. Voyager 2 took more than 9 and a half years to reach Uranus that year. According to previous mission estimates in the ten-year planning stage, even if it relies on the Falcon Heavy and multiple planetary gravity boosts, the flight time may still exceed 13 years. This means that the detector needs to maintain operation and ground support for a long time as it crosses deep space. Funding and key technical teams are always "online" for more than ten years, which is a challenge to management and budget.

In this context, the emergence of starships is considered to be possible to "reshape" the mission architecture. After multiple test flights and improvements, the Starship has recently achieved a more successful test. If the follow-up progress goes smoothly, it is expected to have the capability to launch regular missions by the end of this decade, thus becoming one of UOP's candidate launch platforms. In a paper submitted to the IEEE Aerospace Conference, the research team analyzed that in addition to having a stronger carrying capacity, the starship also has two characteristics that are particularly important for the Uranus mission: one is the orbital refueling capability, and the other is the potential to serve as a reentry and airbrake heat shield. The starship system was designed with orbital refueling in mind, so that it does not need to send all the propellant from the ground into space at once. In theory, it can send probes to the depths of the outer solar system faster and more efficiently.

The paper further explores the idea of ​​a starship directly participating in the Uranus orbit insertion process. Researchers believe that thanks to the starship's thermal protection design for the Earth and Mars re-entry environments, it has the opportunity to serve as a "protective body" for Uranus' atmospheric braking after moderate modifications. In this plan, the starship will not separate from the probe after completing the orbit change. Instead, it will fly to Uranus with UOP and use its own thermal protection system to act as a large "air brake" to help the probe effectively reduce its speed and achieve a stop when passing through Uranus's upper atmosphere. Model calculations show that if in-orbit refueling is combined with starship air brakes, the flight time to Uranus is expected to be shortened from about 13 years to about 6 and a half years, and it will no longer rely on the gravitational assistance of other planets during the flight. Even taking into account the increased development and launch costs of having a starship "accompanying" it, the total operating cost of the mission may still be significantly reduced compared to the current plan because the flight time is halved.

However, there are still many uncertainties in moving from the paper's ideas to actual tasks. UOP is still far from officially establishing the project, and the technological maturity of starships performing complex air brakes under Uranus's atmospheric conditions is far from reaching the engineering feasibility stage. Although the mission ranks as the "number one priority" in the ten-year plan, it is still unclear whether it can receive funding approval as scheduled amid continued budget pressures and internal turmoil within the agency. Once the key launch window of the 2030s is missed, the next relatively ideal launch time will be postponed to the mid-2040s, when the time span from the Voyager 2 flyby to the next close inspection will be close to 70 years. The article concludes by calling that, regardless of whether a starship is ultimately adopted, supporting the Uranus flagship mission should become a consensus among the global planetary science community and relevant institutions, so as not to miss a valuable opportunity to deeply understand this "neglected world".