RP 1, RP-1, RP.1, RP1, or variant may refer to:

• RP-1, Rocket Propellant 1
• RP1, retinitis pigmentosa 1 protein
• RP1 asteroid
  • 5580 Sharidake or 1988 RP1, asteroid Sharidake, RP1 from 1998, the 5580th asteroid catalogued
  • (12728) 1991 RP₁, RP1 from 1991, the 12728th asteroid catalogued
  • 12576 Oresme or 1999 RP1, asteroid Oresme, RP1 from 1999, the 12576th asteroid catalogued
• Mitsubishi RP-1, helicopter
• Rensselaer RP-1, manned glider
• Radioplane RP-1, UAV
• Ready Player One, novel by Ernest Cline

RP-1 (alternately, Rocket Propellant-1 or Refined Petroleum-1) is a highly refined form of kerosene outwardly similar to jet fuel, used as rocket fuel. Although having a lower specific impulse than liquid hydrogen (LH₂), RP-1 is cheaper, stable at room temperature, far less of an explosion hazard and far denser. RP-1 is significantly more powerful than LH₂ by volume. RP-1 also has a fraction of the toxicity and carcinogenic hazards of hydrazine, another room-temperature liquid fuel. Thus, kerosene fuels are more practical for many uses.

In real analysis, the projectively extended real line (also called the one-point compactification of the real line, or simply real projective line), is the extension of the number line by a point denoted . It is thus the set (where is the set of the real numbers), sometimes denoted by The added point is called the point at infinity, because it is considered as a neighbour of both ends of the real line. More precisely, the point at infinity is the limit of every sequence of real numbers whose absolute values are increasing and unbounded.

RP 1, RP-1, RP.1, RP1, or variant may refer to:

• RP-1, Rocket Propellant 1
• RP1, retinitis pigmentosa 1 protein
• RP1 asteroid
  • 5580 Sharidake or 1988 RP1, asteroid Sharidake, RP1 from 1998, the 5580th asteroid catalogued
  • (12728) 1991 RP₁, RP1 from 1991, the 12728th asteroid catalogued
  • 12576 Oresme or 1999 RP1, asteroid Oresme, RP1 from 1999, the 12576th asteroid catalogued
• Mitsubishi RP-1, helicopter
• Rensselaer RP-1, manned glider
• Radioplane RP-1, UAV
• Ready Player One, novel by Ernest Cline

RP-1 (alternately, Rocket Propellant-1 or Refined Petroleum-1) is a highly refined form of kerosene outwardly similar to jet fuel, used as rocket fuel. Although having a lower specific impulse than liquid hydrogen (LH₂), RP-1 is cheaper, stable at room temperature, far less of an explosion hazard and far denser. RP-1 is significantly more powerful than LH₂ by volume. RP-1 also has a fraction of the toxicity and carcinogenic hazards of hydrazine, another room-temperature liquid fuel. Thus, kerosene fuels are more practical for many uses.

In real analysis, the projectively extended real line (also called the one-point compactification of the real line, or simply real projective line), is the extension of the number line by a point denoted . It is thus the set (where is the set of the real numbers), sometimes denoted by The added point is called the point at infinity, because it is considered as a neighbour of both ends of the real line. More precisely, the point at infinity is the limit of every sequence of real numbers whose absolute values are increasing and unbounded.