The choice of liquid propellant may also influence other technology choices. Some liquid propellants are storable, and others must be cryogenically cooled to temperatures approaching absolute zero. The cryogenic coolers make the missile less mobile and more difficult to prepare to fire. The superpowers long ago abandoned nonstorable liquid-propellant missiles for these reasons, but a country that can support the technology to manufacture and store liquid oxygen and hydrogen may find this to be one possible path to making an ICBM.
In a liquid-fueled missile, the supply pressure to feed fuel and oxidizer to the thrust chamber may come either from creating an ullage pressure or pumping the liquids to the thrust chamber with turbopumps. Large volume flow rate pumps, particularly those designed for caustic fuels, have unique applications to ICBM construction. A proliferant may avoid the need for pumps by building tanks within the ICBM to contain an ullage pressure, which forces the liquids into the thrust chambers when the tanks are exposed to this high pressure. In most cases, ullage pressure is structurally less efficient than modern turbopumps because the missile frame must cover the ullage tanks, which are maintained at very high pressure and thus are quite heavy. However, this decrement in range performance is small. Since the technology is simpler to obtain, it may serve the needs of a proliferant. In either case, a liquid missile generally requires valves and gauges that are lightweight, operate with sub-millisecond time cycles, and have a reliable and reproducible operation time. These valves must also accept electrical signals from standard computer interfaces and require little, if any, ancillary electrical equipment.
Too long for hydrogen and oxygen. Have to be something similar to hydrazine. They could be testing tank stability / construction. Or early launch as you said. I can’t remember what they run on. Is this a SCUD variant?