[PAR] [TLE] Able (rocket stage) [SEP] Able rocket stage was a rocket stage manufactured in the United States by Aerojet for the Vanguard rockets used in the Vanguard project from 1957 to 1959.  The rocket engine stage use as a rocket propellant Nitric acid and UDMH.  Able rocket stage was the second of three stages on the multistage rocket Vanguard.  The Able rocket stage was discontinued in 1960.  A further improved versions were used in the upper stage in the Thor rocket family (Thor-Able).  An upgrade to the Able Stage was the Thor-Ablestar rocket.  The Ablestar second stage was an enlarged version of the Able rocket stage, which gave the Thor-Ablestar a greater payload capacity compared to the Thor-Able.  It also incorporated restart capabilities, allowing a multiple-burn trajectory to be flown, further increasing payload, or allowing the rocket to reach different orbits.  It was the first rocket to be developed with such a capability and development of the stage took a mere eight months. [PAR] [TLE] Nitric acid [SEP] Nitric acid (HNO), also known as aqua fortis and spirit of niter, is a highly corrosive mineral acid.
[PAR] [TLE] Able ( rocket stage ) [ SEP ] Able rocket stage was a rocket stage manufactured in the United States by Aerojet for the Vanguard rockets used in the Vanguard project from 1957 to 1959 . The rocket engine stage use as a rocket propellant Nitric acid and UDMH . Able rocket stage was the second of three stages on the multistage rocket Vanguard . The Able rocket stage was discontinued in 1960 . A further improved versions were used in the upper stage in the Thor rocket family ( Thor - Able ) . An upgrade to the Able Stage was the Thor - Ablestar rocket . The Ablestar second stage was an enlarged version of the Able rocket stage , which gave the Thor - Ablestar a greater payload capacity compared to the Thor - Able . It also incorporated restart capabilities , allowing a multiple - burn trajectory to be flown , further increasing payload , or allowing the rocket to reach different orbits . It was the first rocket to be developed with such a capability and development of the stage took a mere eight months . [PAR] [TLE] Nitric acid [ SEP ] Nitric acid ( HNO ) , also known as aqua fortis and spirit of niter , is a highly corrosive mineral acid .
What compound, known as aqua fortis or spirit of niter is used in rocket propellant?
What compound , known as aqua fortis or spirit of niter is used in rocket propellant ?
Nitric acid (HNO), also known as aqua fortis and spirit of niter
Nitric acid (HNO), also known as aqua fortis and spirit of niter