Star 48
Encyclopedia
The Star 48 is a type of solid
rocket motor used by many space propulsion and launch vehicle stages, including the Space Shuttle
and the New Horizons
probe. It is used almost exclusively as an upper stage. It was developed primarily by Thiokol Propulsion
, and now manufactured by ATK
who purchased Thiokol coproration.
The "-48" designation refers to the approximate diameter of the fuel casing in inches; Thiokol had also manufactured other motors such as the Star-37 and Star-40. Internally, Thiokol's designation was TE-M-711 for early versions, and TE-M-799 for later ones. Subtypes are given one or more letter suffixes after the diameter number, or a trailing number (i.e., "-2") after the internal designation. Not surprisingly, the "T" prefix stands for Thiokol, and the following letter refers to the company division that developed the rocket motor. In this case, "E" refers to the Elkton, MD division.
The most common use of the Star-48 is as the final stage of the Shuttle and Delta II
launch vehicles. Other launchers have also incorporated the motor, but with lower frequency. In such usage, the complete stage (motor plus accessories) is referred to as PAM
, Payload Assist Module, as the Shuttle could only take satellites to Low Earth Orbit
. Because Geostationary orbit is much more lucrative, the additional stage was needed for the final leg of the journey. On such missions, the stage is spin-stabilized
. A turntable, mounted in the shuttle payload bay or atop the previous Delta stage, spun the PAM and payload to approximately 60 rpm prior to release.
Usually after motor burnout and just prior to satellite release the PAM is de-spun using a Yo-Yo de-spin
technique.
A non-spinning, thrust-vectoring
version of the Star-48 is available ("Star-48V"), but much less common. A thrust-vectoring Star 48 is the final stage of the Minotaur IV+
Launch Vehicle.
A Star-48 engine used in the 3rd stage of the New Horizons probe was the first part of the New Horizons mission to reach Jupiter
, arriving before the probe. It will eventually cross Pluto
orbit in 2015 at a distance of 200 million kilometers.
A Star-48 Payload Assist Module
that had been used to launch a GPS satellite
in 1993 crashed in the Saudi Arabian desert in January 2001, after its orbit decayed. The unit did not burn up on reentry and was positively identified on the ground.
Solid rocket
A solid rocket or a solid-fuel rocket is a rocket engine that uses solid propellants . The earliest rockets were solid-fuel rockets powered by gunpowder; they were used by the Chinese in warfare as early as the 13th century and later by the Mongols, Arabs, and Indians.All rockets used some form of...
rocket motor used by many space propulsion and launch vehicle stages, including the Space Shuttle
Space Shuttle
The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...
and the New Horizons
New Horizons
New Horizons is a NASA robotic spacecraft mission currently en route to the dwarf planet Pluto. It is expected to be the first spacecraft to fly by and study Pluto and its moons, Charon, Nix, Hydra and S/2011 P 1. Its estimated arrival date at the Pluto-Charon system is July 14th, 2015...
probe. It is used almost exclusively as an upper stage. It was developed primarily by Thiokol Propulsion
Thiokol
Thiokol is a U.S. corporation concerned initially with rubber and related chemicals, and later with rocket and missile propulsion systems...
, and now manufactured by ATK
ATK
ATK may refer to:*America's Test Kitchen, a cooking show on PBS*Alliant Techsystems, a mid-level United States aerospace and defense contractor*Accessibility Toolkit, a GNOME software development toolkit*ATK motorcycles, an off-road motorcycle manufacturer...
who purchased Thiokol coproration.
The "-48" designation refers to the approximate diameter of the fuel casing in inches; Thiokol had also manufactured other motors such as the Star-37 and Star-40. Internally, Thiokol's designation was TE-M-711 for early versions, and TE-M-799 for later ones. Subtypes are given one or more letter suffixes after the diameter number, or a trailing number (i.e., "-2") after the internal designation. Not surprisingly, the "T" prefix stands for Thiokol, and the following letter refers to the company division that developed the rocket motor. In this case, "E" refers to the Elkton, MD division.
The most common use of the Star-48 is as the final stage of the Shuttle and Delta II
Delta II
Delta II was an American space launch system, originally designed and built by McDonnell Douglas. Delta II is part of the Delta rocket family and was in service from 1989 until November 1, 2011...
launch vehicles. Other launchers have also incorporated the motor, but with lower frequency. In such usage, the complete stage (motor plus accessories) is referred to as PAM
Payload Assist Module
frame|PAM-D with the [[Phoenix |Phoenix]] spacecraft. The [[Star 48|Star 48-B]] engine is shown being spun, fired, [[Yo-yo de-spin|yo-yo de-spun]] and jettisoned.thumb|SBS-3 satellite with PAM-D stage inside the space shuttle...
, Payload Assist Module, as the Shuttle could only take satellites to Low Earth Orbit
Low Earth orbit
A low Earth orbit is generally defined as an orbit within the locus extending from the Earth’s surface up to an altitude of 2,000 km...
. Because Geostationary orbit is much more lucrative, the additional stage was needed for the final leg of the journey. On such missions, the stage is spin-stabilized
Spin-stabilized satellite
A spin-stabilized satellite is a satellite which has the motion of one axis held fixed by spinning the satellite around that axis, using the gyroscopic effect.The attitude of a satellite or any rigid body is its orientation in space...
. A turntable, mounted in the shuttle payload bay or atop the previous Delta stage, spun the PAM and payload to approximately 60 rpm prior to release.
Usually after motor burnout and just prior to satellite release the PAM is de-spun using a Yo-Yo de-spin
Yo-yo de-spin
frame|[[Payload Assist Module|PAM-D]] upper stage with the [[Phoenix |Phoenix]] spacecraft. The [[Star 48|Star 48-B]] engine is shown being spun, fired, yo-yo de-spun and jettisoned....
technique.
A non-spinning, thrust-vectoring
Thrust vectoring
Thrust vectoring, also thrust vector control or TVC, is the ability of an aircraft, rocket or other vehicle to manipulate the direction of the thrust from its engine or motor in order to control the attitude or angular velocity of the vehicle....
version of the Star-48 is available ("Star-48V"), but much less common. A thrust-vectoring Star 48 is the final stage of the Minotaur IV+
Minotaur IV
Minotaur IV, also known as Peacekeeper SLV and OSP-2 PK is an active expendable launch system derived from the Peacekeeper missile. It is operated by Orbital Sciences Corporation, and made its maiden flight on 22 April 2010, carrying the HTV-2a Hypersonic Test Vehicle...
Launch Vehicle.
A Star-48 engine used in the 3rd stage of the New Horizons probe was the first part of the New Horizons mission to reach Jupiter
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...
, arriving before the probe. It will eventually cross Pluto
Pluto
Pluto, formal designation 134340 Pluto, is the second-most-massive known dwarf planet in the Solar System and the tenth-most-massive body observed directly orbiting the Sun...
orbit in 2015 at a distance of 200 million kilometers.
A Star-48 Payload Assist Module
Payload Assist Module
frame|PAM-D with the [[Phoenix |Phoenix]] spacecraft. The [[Star 48|Star 48-B]] engine is shown being spun, fired, [[Yo-yo de-spin|yo-yo de-spun]] and jettisoned.thumb|SBS-3 satellite with PAM-D stage inside the space shuttle...
that had been used to launch a GPS satellite
GPS satellite
A GPS satellite is a satellite used by the NAVSTAR Global Positioning System . The first satellite in the system, Navstar 1, was launched February 22, 1978. The GPS satellite constellation is operated by the 50th Space Wing of the United States Air Force....
in 1993 crashed in the Saudi Arabian desert in January 2001, after its orbit decayed. The unit did not burn up on reentry and was positively identified on the ground.