Starship debut leading the rocket industry toward full reusability

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Starship’s first orbital flight is currently planned for March. This is the first time the anticipated flight date of the vehicle is in the current month, and with that, a future of fully reusable rockets is getting closer. But not only is Starship aiming for reusability, but the rest of the industry is also moving toward reusing rockets.

This is the case for rockets in the United States and programs such as the Ariane NEXT in Europe or Chang Zheng 9 in China.

Falcon 9 versus Super Heavy

The obvious part of reusability is the booster. SpaceX already demonstrated the partial reusability of rocket stages with the landing of the Falcon 9. Initially, the company even intended to explore reusability for their much smaller Falcon 1 vehicle, but in December 2015, Falcon 9 became the first orbital class first stage to land safely back on the ground.

Falcon 9 landing during the Transporter-6 mission. (Credit: SpaceX)

SpaceX is choosing a similar approach for Super Heavy, with some modifications. The obvious one is the modification of the landing profile, as the Super Heavy Booster will not land on a drone ship or landing pad, like Falcon 9, but instead land on the Chopsticks of the launch and landing tower called Mechazilla.

This change eliminates the need for landing legs for the Booster, as it will never go beyond Earth, where it might need landing legs after all. SpaceX eliminated the mass of the landing legs from the design and put that weight onto stage zero, so there is less mass penalty for the landing.

The other subtle change is the switching of the engine profile for reentering. While the booster for Falcon 9 performs a reentry burn to protect itself against the heat and speed during entry, the Booster for Starship is designed not to need such a capability. It will endure the higher forces during reentry with its robust design rather than actively braking.

Starship

The path is more novel for the vehicle’s upper stage, as it will perform a reentry and landing profile, which is much different from previously performed rocket landings. While the reentry has some similarities with the Space Shuttle, mainly in how it will endure the heating during the reentry using thermal protection tiles, the landing with the so-called “belly flop” is much different.

In this maneuver, the rocket will cancel its horizontal velocity and then perform a skydiver-like “belly flop” maneuver to reduce its vertical velocity before using the engines and fins to turn and land the vehicle in a vertical orientation.

In contrast, after the Space Shuttle performed its reentry, it glided to the runway and stopped using landing gear and parachutes. It did not use thrusters or any kind of propulsion for the landing itself.

Previously, SpaceX considered using no heatshield tiles for Starship’s main body, instead using transpirational cooling. This would dispose of liquids outside the Ship, vaporizing to carry away the heat and energy on the vehicle’s surface.

For earlier SpaceX prototypes, the Starship still was equipped with landing legs, and these were used for the SN5 to SN15 vehicles, when SpaceX performed test landings.

Based on Elon Musk’s comments, the Ship in the future will land similarly to the Booster planned. Of course, the company will still need to develop landing legs for landings on Moon and Mars, as no landing towers are available there.

Booster landing as shown in SpaceX renders. (Credit: SpaceX)

This kind of first and second stage reusability, in combination with the fact that Starship does not use fairings but rather a re-closable payload bay, will mean that the company will reuse 100 percent of the hardware necessary for flight. Resulting in an ever higher cost advantage than the company already has with its reuse of first stage boosters on Falcon 9 and Falcon Heavy.

The final cost savings depends on the vehicle’s refurbishment results, and how much money saved by not building new vehicles is needed to inspect the active fleet. Especially the Space Shuttle, with its refurbish-able SRBs, showed that it can be a complex topic that will only become a clear picture years after flying.

Beyond SpaceX – Fully Reusable

With one competitor moving to reusability, the rest of the industry started adapting to offer competitive prices next to SpaceX. Most space companies at this point have announced plans to move their vehicles to at least a partially reusable future, and some of the newer companies even announced fully reusable concepts.

One of the fully reusable concepts is the Terran R rocket from Relativity Space. While their first rocket, Terran 1, is also slated to debut this month, the company has already started working on a fully reusable rocket. The medium-lift two-stage rocket plans to lift up to 20,000 kg into low Earth orbit, with a no earlier than (NET) flight date of 2024. Tim Ellis, the company CEO, has actively made comparisons to the giant rocket designed by SpaceX.

Terran R render. (Credit: Relativity Space)

Relativity could become a smaller alternative to SpaceX with its super-heavy launch vehicle if it succeeds in its path.

Next to Relativity, Blue Origin is also working on a fully reusable future. While the company already has a fully reusable suborbital vehicle with New Shepard, New Glenn is the giant leap the company has planned.

New Glenn was initially announced as a partially reusable vehicle, where the first stage would land again, while the second stage would be expendable. However, after July 2021, it seems the company shifted its approach to the second stage and started constructing “Project Jarvis.” This project is reportedly part of the development of a fully reusable upper stage for New Glenn.

The upper stage also uses stainless steel, as test tanks have been spotted outside of Blue Origin facilities at the Cape regularly. It is also unknown when Blue Origin plans to debut its second stage reusability, but any fully reusable version of New Glenn is expected to be an evolution rather than the initial configuration.

Beyond SpaceX – Partial Reusable

Rocket Lab plans partial reusability for both its current and future vehicles.

With its current rocket, Electron, it was initially planned to catch the rocket with a helicopter before placing it on a sea asset and bringing it back to land. In a recent investor briefing, however, the company indicated that this strategy might shift as they explore opportunities to remove the helicopter from the equation.

This could result in simply using parachutes to slow down the rocket before recovering it with a sea asset after splashdown.

Render of a partially reusable Neutron releasing a second stage. (Credit: Rocket Lab)

There is a different approach for the upcoming Neutron rocket, which plans to debut in 2024 or later. The rocket’s main body will be fully reusable and open in a chomper-style system, releasing the second stage before returning to Earth. Combined with a cheap-to-produce upper stage, this would lower costs for the vehicle while only being in a partially reusable configuration.

Vulcan Center core with two non-reusable BE-4 engines. (Credit: ULA)

For United Launch Alliance (ULA), a path to reusability might include the Sensible Modular Autonomous Return Technology (SMART). ULA, in the past, has voiced doubts about the financial viability of developing technology to reuse the first stage of a vehicle. With SMART, the aim is to recover the first stage’s engines, which would recover 65 percent of the total first stage costs.

In this concept, a heatshield would protect the BE-4 engines, built by Blue Origin, during reentry, before arriving back on Earth for reuse after splashing down in the ocean. There is no timeline yet for when ULA aims to implement SMART on Vulcan, but with Kuiper and the high launch cadence coming up for the company, CEO Tory Bruno voiced the need for reusability.

In Europe, the ArianeGroup and ESA announced the SALTO (reuSable strAtegic space Launcher Technologies & Operations), also referred to as Ariane Next. The preliminary steps to this reusable launch vehicle include the technology demonstrators Themis and Callisto, which aim to test technology related to propulsive landing.

After this, the new Prometheus rocket engine would enable different configurations of an Ariane rocket, which would be able to land on Earth again. The concept is vague and undetailed and has no clear schedule going forward.

Next to the ArianeGroup, several other European companies, such as Rocket Factory Augsburg, have announced general intentions to move to a reusable rocket future. However, none of these plans are detailed as of now.

In China, the big upcoming governmental rocket, Chang Zheng 9, will at least feature partial reusability. In recent renders and pictures, the current design of the rocket is always shown with grid fins, and it was said in the past that the head of design, Dr. Long Lehao, wants to make the huge government rocket reusable.

As of now, the design of the rocket is not final, and it has not been outlined when and how Chang Zheng 9 plans to be reusable. New hardware for the giant rocket has just appeared, but it will most likely not fly before 2030.

D10.6m propellant tank of Long March 9 https://t.co/0Es77RSDiK pic.twitter.com/TorgIVysde

— China 'N Asia Spaceflight (@CNSpaceflight) March 2, 2023

Other Chinese companies and startups have also indicated their move to reusable rockets. For example, the Chinese company LandSpace recently started testing restartable rocket engines.

Summary

Overall, the move to reusability can be seen in almost every sector of launch systems. SpaceX is the first to fly a partially reusable system and will almost certainly be the first to fly a fully reusable one, while other companies are moving quickly toward reusability as well. These designs are not solely copies of SpaceX’s approach, but rather find new ideas to try to recover rocket stages to make access to space cheaper.

(Lead image: Boca Chica and the launch pad. Credit: Jack Beyer for NSF)

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