Susie's back, tell a friend

ArianeGroup has revealed a 1/6th prototype of its Susie spacecraft

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Susie's back, tell a friend

Credit: ArianeGroup

In a development that surprised many, ArianeGroup announced last week that it had built and would begin testing a small prototype of its Smart Upper Stage for Innovative Exploration (SUSIE) vehicle. 

As a refresher, Susie was introduced by ArianeGroup during the International Astronautical Congress in September 2022. The vehicle will be 12 metres tall, five metres wide, and would have a payload capacity of seven tonnes. It would be launched aboard an Ariane 64 and would be used for multiple roles, including crew and cargo transport and servicing missions.

With the announcement last week, we got the first signs of progress from the project. Interestingly, the announcement was not made by ArianeGroup itself. It was given to French business magazine L'Usine nouvelle, which published it behind a paywall on 25 October 2023. ArianeGroup has since published a few social posts discussing the prototype. When piecing the information that’s come out together, things, dare I say it, may actually be looking up for this programme. 

The prototype

The Susie prototype is two metres tall and has a mass of 100 kilograms. According to ArianeGroup, this represents a 1/6th scale demonstrator of Susie. The company has referred to the vehicle as a modular "test and learn platform" that is "designed to progressively explore and expand the flight envelope in a step-by-step approach."

According to the L'Usine nouvelle article, the 1/6th demonstrator is equipped with “four thrusters.” The article also stated that ArianeGroup had "carried out the first ignition" of these thrusters at the company’s Les Mureaux test facility. I did Google Translate the article from French, so I may just be losing something in translation. However, according to a comment on an ArianeGroup LinkedIn post from Cécilia Matissart, chief of strategy and innovation officer at ArianeGroup, the "thrusters" are actually turbojet engines, which are basically small aeroplane engines that you could purchase off-the-shelf from a hobby shop.

Testing of the prototype will begin with short hops under manual control. The goal is to eventually achieve an altitude of around 2,000 metres followed and an autonomous landing. The landing will be performed “using its engines or a parachute.” This testing is expected to continue until the second quarter of 2025. 

While the company moves ahead with testing the 1/6th demonstrator, ArianeGroup is already working on an “operational half-size Susie.” According to the company, this vehicle could be launched under the fairing of an Ariane 6 launch vehicle to offer an “initial capability to bring cargo up and back down from a space station.”

According to the L'Usine nouvelle article, ArianeGroup is now looking at offering Susie in two different sizes. An intermediate size will feature a ten cubic metre cargo bay and will be capable of carrying payloads of up to three tonnes. This variant sounds a lot like the “half-size” Susie described by ArianeGroup. The full-sized Susie spacecraft is what was first announced. This variant would feature a 40 cubic metre cargo bay and would be capable of ferrying seven-tonne payloads to orbit. In a crewed configuration, both will be able to accommodate up to five astronauts. 

Why the half pint?

The smaller variant of Susie is an interesting development. One could easily conclude that it is merely a development milestone that would allow ArianeGroup to gain flight pedigree while it worked on the larger vehicle. However, I think it’s more than that.

In May, ESA launched its Commercial Cargo Transportation Initiative (CCTI). The initiative aims to encourage European industry to develop space cargo transportation systems that could service the International Space Station and future commercial stations. 

CCTI candidate vehicles are required to transport a minimum of two tonnes of cargo to the ISS and return at least one tonne back to Earth. Initial demonstration missions are required to be launched by 2028. Companies that successfully complete these objectives will then receive actual service contracts.

Right to left: ArianeGroup Susie, The Exploration Company Nyx, and Rocket Factory Augsburg Argo

The requirements for CCTI candidates seem to fall within the capabilities of the smaller version of Susie. It would, as a result, not surprise me if ArianeGroup threw Susie into the ring with Rocket Factory Augsburg’s Argo and The Exploration Company’s Nyx spacecraft to compete for a phase one CCTI contract. 

Curious timing

The European Space Summit will take place on 6 and 7 November. During the first day, an ESA council meeting will see ministers of ESA member states discuss, among other things, the commercialization and privatization of space transportation. On the second day, the space ministers of the European Union will join the ESA council to discuss, again, among other things, securing autonomous, reliable, and cost-effective access to space for Europe. 

The decisions made at these two meetings will likely not represent any major budgetary commitments, but they will certainly be key in outlining the future of ESA space transportation programmes. It is, as a result, a perfect time for ArianeGroup to be seen making rapid progress on what it has called "a flagship project in ArianeGroup's innovation portfolio." The timing does, as a result, make me immediately suspicious. Has ArianeGroup thrown together a model of Susie that looks great on video and in images but represents very little real engineering progress? I would like to think not, but I certainly can't be sure. I was struck by how closely the prototype resembles the mockups. I feel like an early prototype like this could have followed function more than form. This is, however, very speculative. What is far less speculative is that the timing of this announcement just weeks before the European Space Summit is no accident.

Conclusion

I hated the Susie concept when it was first announced. It felt like ArianeGroup was repeating all the mistakes of Hermes. In fact, I published a newsletter issue entitled “Funding ArianeGroup’s Susie concept would be a mistake.” While I am suspicious about the timing of this announcement so close to the Space Summit meetings in which vehicles like this will undoubtedly be discussed, I am kind of warming to Susie as much as I dislike admitting it.

I still think a full-sized multi-role Susie spacecraft is a mistake. However, a half-size Susie dedicated to cargo missions that ditches the propulsive landing, at least initially, for parachutes is significantly more appealing. Now, to be clear, that’s not exactly what ArianeGroup is describing here. It sounds like the company will be using the small prototype to work towards that complex propulsive landing system until the middle of 2025, with parachutes being used as a backup to the turbojets. My preference would be to completely move to a parachute-based system that could be rapidly tested aboard the 1/6th prototype. The company could then aim to have the half-sized operational vehicle ready to fly by 2026. That would allow Susie to gain flight pedigree, with ArianeGroup working on a crew version while the necessary upgrades for a crew-rated Ariane 6 are being implemented. Although I would be happy for ESA to supply a portion of the funding for this programme, I would want ArianeGroup to have at least an equal, if not greater, stake in the development costs.