In September 2024, CubeCab began work on Department of Energy grant DE-SC0025111, to investigate the regulatory and technical feasibility of a nuclear thermal launch vehicle. This design uses the extreme temperature of a small fission reactor to heat propellant beyond what chemical rockets are capable of, so as to use its propellant more efficiently. It is based on the MITEE design published in prior Department of Energy studies, with changes such as using low enriched uranium instead of MITEE's high enriched uranium.

"Technical feasibility" boils down to, "will it perform its given mission with the necessary safety systems?" "Regulatory feasibility" means discussing the existing licensing processes with the Nuclear Regulatory Commission and Federal Aviation Administration, among others. Said processes involve due consideration for potential harm to the environment and to the public.

Although we are considering a number of form factors for a launch vehicle that might use the engine, the ones we are investigating can reach Low Earth Orbit in a single stage, which is impossible for traditional rocket designs. They are also designed for reusability, returning to the launch point after depositing their payload in orbit, with safe abort options in case something goes wrong during reentry.

Any nuclear system to be used near the public, or inside Earth's atmosphere at all, should be designed for safety. Our design uses a "closed cycle", where the exhaust will not be substantially more radioactive than a typical chemical rocket's. Sufficient shielding to limit gamma emissions to safe levels at the public keep-away distance must also be present; materials to do this without weighing the rocket down enough that it could not launch were much harder to find some years ago. So long as these challenges (and others common to nuclear facilities, such as disposal of depleted fuel) are handled, there may be some environmental benefits relative to traditional rockets, as we do not need the toxic chemicals that certain other rockets use, nor do we intend to drop rocket stages mid-flight.

If our study results in a launch vehicle of our design, our plan is that the first such launch vehicle will be small, to minimize development cost and risk to the public; far too small to carry a human being as crew or passenger. The target market will be small, low-budget missions, mostly of interest to non-government customers such as universities or small businesses. Scale-up to serve larger payloads can be done after several flights have shown how to do larger versions safely.

Some may spread misinformation about this project, some with the aim of causing damage and/or fatalities through panic. Our best defense is the truth. While we cannot give all the details in public, due in part to laws restricting distribution of the technical data involved, we will aim to at least provide summaries when we can and at the depth we can legally. Technically minded readers may have thought of a number of points this summary does not, and is not legally allowed to, answer.

Results of our study will be published once the study is complete, which is estimated to be around late March or early April 2025. We are not proposing to actually handle any nuclear fuel before our study is complete: there is sufficient experimental data to do our analysis. (If a summary is not posted here after April 2025, then the study is delayed. It is our intention to post at least a summary here once we are done.)

Our former primary launch vehicle design. This was an air launched, 4-stage (including the aircraft), solid-fueled launch vehicle designed to take a single 3U CubeSat to Low Earth Orbit. The key to success was mass production: building rockets 10 or 20 at a time, for economies of scale and so we could test one rocket out of each batch to ensure quality.

Development is on pause while we conduct the nuclear thermal investigation. If that works, it will obsolete the Cab-3A, though many of the lessons learned while pursuing development of the Cab-3A will be incorporated.

This is a design to turn orbital debris into propellant. The concept is a small drone (a 3U CubeSat) that seeks out small (under 10 cm, too small for ground radar to reliably detect) particles of debris at fairly close range (1 km or less), accelerates up to them and collides at low relative velocity, then shreds them into small particles. These particles can be used as propellant for an ion engine (meaning this drone might never run out of fuel, so long as there remains debris as an in situ resource) or dumped at some repository for use as feedstock.

If used as propellant, the particles are too small to cause damage, just like exhaust from other rockets.

Unfortunately, cleaning up orbital debris is a tragedy of the commons: there is no one designated to pay for it. Efforts to put a single U.S. government office in charge of cleanup of U.S. debris have resulted in an extended round of hot potato, and then there are legal problems with cleaning up someone else's debris. (For instance, there have been worries that if a U.S. company cleans up Russian debris, Russia could sue in U.S. courts for theft of its property, even if the debris was deliberately aimed at U.S. satellites and this cleanup was done to protect them.)

Please see our entry at contest.techbriefs.com/2022/entries/aerospace-and-defense/11722

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