Texas Starship Testing

Driving back from Texas, I had a Gedankenexperiment. Today, long range artillery rockets and missiles have a high explosive warhead. But if it were oxygen and methane fueled, the uncombusted reactants could be mixed as it approached the target and then ignited. Such a weapon would have a variable, explosive yield trade-off with range.

The weapon would also be exceptionally light, with more than an order of magnitude, warhead effect. The rocket could use a simple pressure feed system with the thicker body becoming the shrapnel. This would allow a family of rockets from smaller, ATACMS to substantially larger, airport and refinery targeting missiles. Should also work an bridges, especially rail road bridges.

Bob Wilson

 

Similar idea but using 100% O{2} instead of 20% O{2} and 80% N{2}.

There are non-trivial problems such as the boiling points, O{2} (54-90 K) and methane (91-112 K). Solvable with pressure management and given it would be in a single body.

A nice technical write up on the type of rocket: Introduction to PROMETHEUS - ARIS.

Replace ethanol with liquid methane:


As a munition, a much simpler, cheaper system would be used. Light weight pressure tank with a thin, internal baffle separating the liquid methane and oxygen. A small explosive can eliminate the baffle for mixing. At the rear, a simple, one time use, engine and control logic.

As the missile ends powered flight, blow the baffle to mix. Then just prior to impact, open valves to engine and fire the igniter. It should make an impressive bang with plenty of shrapnel.

Bob Wilson

 

Absent experimentation, I’ve assumed a very, high speed explosive In possibly a sealed, thin tube. Just enough to rupture the baffle but not the outer casing. But there are non pyrotechnics that could work too.

Bob Wilson

 

Ours since the Titan was retired, are solid fuel. Less performance per pound than liquid fuel, they are a whole lot easier to store and fire.

The one exception are military payloads launched to orbit. But those rockets are contracted to established, liquid fuel, rocket providers.

Bob Wilson

 

Correct. I'm thinking of the Ukrainians. They are clever people (as the Russian are learning,) and a simple missile as outlined should easily reach deep, 300-1,200 km, into Russia to deliver a powerful, binary liquid fuel explosive, the unburned propellant. Mechanically simple using LOX and LNG as both propellant and warhead.

Bob Wilson

 

Found an interesting paper: https://arc.aiaa.org/doi/epdf/10.2514/6.2019-4283

Synopsis of LOX/Liquid Methane & Liquid Natural Gas Rocket Propellant Explosion Hazards

Alan M. Sutton!, Claude E. Merrill?, and Nils M. Sedano Air Force Research Laboratory, Edwards AFB, CA 93524, USA Alexandra M. Ortiz*461$ FTS, AFTC, Edwards AFB CA 93524,

USA Liquid Oxygen LO2, and Liquid Methane (LCH.) or Liquid Natural Gas (LNG) are liquid rocket propellant combinations receiving much interest. To date, no methane fueled launch vehicle has flown, although some small experimental demonstrators have conducted successful free flights.[1] The proposed use of this propellant combination in contemporary launch vehicles has created a need to determine the propellant explosion hazards. Quantification of the explosive energy release is needed to facilitate proper planning of range safety, launch facilities construction, and test site layout. As part of this estimating process LOMethane theoretical and thermochemical modeling of energy release are examined and compared to operational propellants, including discussion of the legal and regulatory consideration and historical methods of determining net explosive weight. Unlike established propellants (e.g. LO/LH2 and LO/RP-1) that do not have a common temperature and pressure liquid range, the LOz/Methane propellant combination offers a unique condition where the propellants share a similar liquid state.​

Although not perfect for my purposes:

BTW, engine "knock" is a detonation of the fuel air mix, typically regular fuel at ~13-14 atmospheres. The body of a the simple rocket would be at much higher, engine chamber pressures, typically +200 atmospheres. Detonation won't be a problem.

Bob Wilson

 

About Starship, rumors are:

• Flap hinges will be moved and better protected with an improved tile barrier.
  • IMHO, aerodynamic structures like wings should not be put on space craft.
• An under, ablative layer behind the tiles to handle tile failures.
  • Sensible given how one tile failure should not cause vehicle loss on re-entry.
  • This is a solvable but not trivial engineering problem.

Bob Wilson