Abstract: Disclosed is a turbo pump in which a pump impeller is connected to one end of a rotary shaft and a turbine is connected to the other end of the rotary shaft. The turbo pump is designed such that an equivalent region, between a turbine efficiency curve obtained on the basis of a conditional expression where the number of rotations of the rotary shaft is maintained constant regardless of a pump flow rate and a turbine efficiency curve of an actual machine, becomes an operation region.

Abstract: Disclosed is a turbo pump in which a pump impeller is connected to one end of a rotary shaft and a turbine is connected to the other end of the rotary shaft. The turbo pump is designed such that an equivalent region, between a turbine efficiency curve obtained on the basis of a conditional expression where the number of rotations of the rotary shaft is maintained constant regardless of a pump flow rate and a turbine efficiency curve of an actual machine, becomes an operation region.

Abstract: The invention relates to an ablator composition for providing ablation protection. The ablator composition comprises 100 parts by weight of a mixture of vinyl-containing organopolysiloxanes, the mixture containing 50-80 wt. % of a diorganopolysiloxane which contains vinyl groups and 20-50 wt. % of a silicone resin which contains vinyl groups; an organohydrogenpolysiloxane containing in one molecule thereof at least three hydrogen atoms which are directly bonded to silicon atoms thereof; a catalyst which is at least one selected from the group consisting of metallic platinum and platinum compounds; up to 150 parts by weight of silica microballoons; and at least one selected from the group consisting of up to 15 parts by weight of quartz glass fibers and up to 15 parts by weight of carbon fibers. An ablator material prepared by curing the ablator composition has a low surface recession rate even under a condition of a high heating rate such as about 4 MW/m.sup.