Roll program

Last updated

A roll program or tilt maneuver is an aerodynamic maneuver that alters the attitude of a vertically launched space launch vehicle. The maneuver is used to place the spacecraft on a proper heading toward its intended orbit. It often consists of a partial rotation around the vehicle's vertical axis ("roll") followed by tilting the vehicle ("pitch") to follow the proper gravity turn and/or to improve aerodynamics.

Contents

A roll program is completed shortly after the vehicle clears the tower. In the case of a crewed mission, a crew member (usually the commander) reports the roll to the mission control center which is then acknowledged by the capsule communicator. [1]

Saturn V

The Saturn V's roll program was initiated shortly after launch and was handled by the first stage. It was open-loop: the commands were pre-programmed to occur at a specific time after lift-off, and no closed loop control was used. This made the program simpler to design at the expense of not being able to correct for unforeseen conditions such as high winds. The rocket simply initiated its roll program at the appropriate time after launch, and rolled until an adequate amount of time had passed to ensure that the desired roll angle was achieved. [2]

Roll on the Saturn V was initiated by tilting the engines simultaneously using the roll and pitch servomechanisms, which served to initiate a rolling torque on the vehicle. [3]

Space Shuttle

Space Shuttle Atlantis performs the roll maneuver shortly after launching from Kennedy Space Center on STS-129. STS-129 Atlantis roll program.PNG
Space Shuttle Atlantis performs the roll maneuver shortly after launching from Kennedy Space Center on STS-129.

During the launch of a Space Shuttle, the roll program was simultaneously accompanied by a pitch maneuver and yaw maneuver. [4]

The roll program occurred during a Shuttle launch for the following reasons:

The RAGMOP computer program (Northrop) in 1971–72 discovered a ~20% payload increase by rolling upside down. It went from ~40,000 lb to ~48,000 lb to a 150 NM equatorial orbit without violating any constraints (max Q, 3 G limit, etc.). So the incentive to roll was initially for the payload increase by minimizing drag losses and moment balancing losses by keeping the main engine thrust vectors more parallel to the SRBs. [5]

Related Research Articles

<span class="mw-page-title-main">Space Shuttle</span> Partially reusable launch system and space plane

The Space Shuttle is a retired, partially reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. Its official program name was Space Transportation System (STS), taken from a 1969 plan for a system of reusable spacecraft where it was the only item funded for development.

<span class="mw-page-title-main">Centaur (rocket stage)</span> Family of rocket stages which can be used as a space tug

The Centaur is a family of rocket propelled upper stages that has been in use since 1962. It is currently produced by U.S. launch service provider United Launch Alliance, with one main active version and one version under development. The 3.05 m (10.0 ft) diameter Common Centaur/Centaur III flies as the upper stage of the Atlas V launch vehicle, and the 5.4 m (18 ft) diameter Centaur V has been developed as the upper stage of ULA's new Vulcan rocket. Centaur was the first rocket stage to use liquid hydrogen (LH2) and liquid oxygen (LOX) propellants, a high-energy combination that is ideal for upper stages but has significant handling difficulties.

<span class="mw-page-title-main">Marshall Space Flight Center</span> Rocketry and spacecraft propulsion research center

The George C. Marshall Space Flight Center (MSFC), located in Redstone Arsenal, Alabama, is the U.S. government's civilian rocketry and spacecraft propulsion research center. As the largest NASA center, MSFC's first mission was developing the Saturn launch vehicles for the Apollo program. Marshall has been the lead center for the Space Shuttle main propulsion and external tank; payloads and related crew training; International Space Station (ISS) design and assembly; computers, networks, and information management; and the Space Launch System. Located on the Redstone Arsenal near Huntsville, MSFC is named in honor of General of the Army George C. Marshall.

<span class="mw-page-title-main">STS-1</span> First Space Shuttle mission, first orbital flight of the Space Shuttle Columbia

STS-1 was the first orbital spaceflight of NASA's Space Shuttle program. The first orbiter, Columbia, launched on April 12, 1981, and returned on April 14, 1981, 54.5 hours later, having orbited the Earth 37 times. Columbia carried a crew of two—commander John W. Young and pilot Robert L. Crippen. It was the first American crewed space flight since the Apollo–Soyuz Test Project (ASTP) in 1975. STS-1 was also the maiden test flight of a new American spacecraft to carry a crew, though it was preceded by atmospheric testing (ALT) of the orbiter and ground testing of the Space Shuttle system.

<span class="mw-page-title-main">STS-39</span> 1991 American crewed spaceflight for the Department of Defense

STS-39 was the twelfth mission of the NASA Space Shuttle Discovery, and the 40th orbital shuttle mission overall. The primary purpose of the mission was to conduct a variety of payload experiments for the U.S. Department of Defense (DoD).

<span class="mw-page-title-main">Space Shuttle Solid Rocket Booster</span> Solid propellant rocket used to launch the Space Shuttle orbiter

The Space Shuttle Solid Rocket Booster (SRB) was the first solid-propellant rocket to be used for primary propulsion on a vehicle used for human spaceflight. A pair of these provided 85% of the Space Shuttle's thrust at liftoff and for the first two minutes of ascent. After burnout, they were jettisoned and parachuted into the Atlantic Ocean where they were recovered, examined, refurbished, and reused.

<span class="mw-page-title-main">Saturn IB</span> American rocket used in the Apollo program during the 1960s and 70s

The Saturn IB(also known as the uprated Saturn I) was an American launch vehicle commissioned by the National Aeronautics and Space Administration (NASA) for the Apollo program. It uprated the Saturn I by replacing the S-IV second stage, with the S-IVB. The S-IB first stage also increased the S-I baseline's thrust from 1,500,000 pounds-force (6,700,000 N) to 1,600,000 pounds-force (7,100,000 N) and propellant load by 3.1%. This increased the Saturn I's low Earth orbit payload capability from 20,000 pounds (9,100 kg) to 46,000 pounds (21,000 kg), enough for early flight tests of a half-fueled Apollo command and service module (CSM) or a fully fueled Apollo Lunar Module (LM), before the larger Saturn V needed for lunar flight was ready.

<span class="mw-page-title-main">Orbiter Processing Facility</span> Hangars formerly used for Space Shuttle maintenance at NASAs Kennedy Space Center

Orbiter Processing Facility (OPF) is a class of hangars where U.S. Space Shuttle orbiters underwent maintenance between flights. They are located west of the Vehicle Assembly Building, where the orbiter was mated with its external tank and Solid Rocket Boosters before transport to the launch pad. OPF-1 and OPF-2 are connected with a low bay between them, while OPF-3 is across the street.

<span class="mw-page-title-main">Launch vehicle</span> Rocket used to carry a spacecraft into space

A launch vehicle is typically a rocket-powered vehicle designed to carry a payload from Earth's surface or lower atmosphere to outer space. The most common form is the ballistic missile-shaped multistage rocket, but the term is more general and also encompasses vehicles like the Space Shuttle. Most launch vehicles operate from a launch pad, supported by a launch control center and systems such as vehicle assembly and fueling. Launch vehicles are engineered with advanced aerodynamics and technologies, which contribute to high operating costs.

<span class="mw-page-title-main">Space Shuttle design process</span> Development program of the NASA Space Shuttle

Before the Apollo 11 Moon landing in 1969, NASA began studies of Space Shuttle designs as early as October 1968. The early studies were denoted "Phase A", and in June 1970, "Phase B", which were more detailed and specific. The primary intended use of the Phase A Space Shuttle was supporting the future space station, ferrying a minimum crew of four and about 20,000 pounds (9,100 kg) of cargo, and being able to be rapidly turned around for future flights, with larger payloads like space station modules being lifted by the Saturn V.

<span class="mw-page-title-main">Ares V</span> Canceled NASA rocket key to Project Constellation

The Ares V was the planned cargo launch component of the cancelled NASA Constellation program, which was to have replaced the Space Shuttle after its retirement in 2011. Ares V was also planned to carry supplies for a human presence on Mars. Ares V and the smaller Ares I were named after Ares, the Greek god of war.

<span class="mw-page-title-main">Space Shuttle orbiter</span> Reusable spacecraft component of the Space Shuttle system

The Space Shuttle orbiter is the spaceplane component of the Space Shuttle, a partially reusable orbital spacecraft system that was part of the discontinued Space Shuttle program. Operated from 1981 to 2011 by NASA, the U.S. space agency, this vehicle could carry astronauts and payloads into low Earth orbit, perform in-space operations, then re-enter the atmosphere and land as a glider, returning its crew and any on-board payload to the Earth.

<span class="mw-page-title-main">Saturn C-3</span> Third rocket in the Saturn C series studied from 1959 to 1962

The Saturn C-3 was the third rocket in the Saturn C series studied from 1959 to 1962. The design was for a three-stage launch vehicle that could launch 45,000 kilograms (99,000 lb) to low Earth orbit and send 18,000 kilograms (40,000 lb) to the Moon via trans-lunar injection.

<span class="mw-page-title-main">Gravity turn</span> Spacecraft launch or descent maneuver

A gravity turn or zero-lift turn is a maneuver used in launching a spacecraft into, or descending from, an orbit around a celestial body such as a planet or a moon. It is a trajectory optimization that uses gravity to steer the vehicle onto its desired trajectory. It offers two main advantages over a trajectory controlled solely through the vehicle's own thrust. First, the thrust is not used to change the spacecraft's direction, so more of it is used to accelerate the vehicle into orbit. Second, and more importantly, during the initial ascent phase the vehicle can maintain low or even zero angle of attack. This minimizes transverse aerodynamic stress on the launch vehicle, allowing for a lighter launch vehicle.

<span class="mw-page-title-main">STS-135</span> 2011 American crewed spaceflight to the ISS and final flight of the Space Shuttle program

STS-135 was the 135th and final mission of the American Space Shuttle program. It used the orbiter Atlantis and hardware originally processed for the STS-335 contingency mission, which was not flown. STS-135 launched on July 8, 2011, and landed on July 21, 2011, following a one-day mission extension. The four-person crew was the smallest of any shuttle mission since STS-6 in April 1983. The mission's primary cargo was the Multi-Purpose Logistics Module (MPLM) Raffaello and a Lightweight Multi-Purpose Carrier (LMC), which were delivered to the International Space Station (ISS). The flight of Raffaello marked the only time that Atlantis carried an MPLM.

<span class="mw-page-title-main">Saturn V</span> American super heavy-lift expendable rocket

The Saturn V is a retired American super heavy-lift launch vehicle developed by NASA under the Apollo program for human exploration of the Moon. The rocket was human-rated, had three stages, and was powered by liquid fuel. Flown from 1967 to 1973, it was used for nine crewed flights to the Moon, and to launch Skylab, the first American space station.

<span class="mw-page-title-main">Chrysler SERV</span>

SERV, short for Single-stage Earth-orbital Reusable Vehicle, was a proposed space launch system designed by Chrysler's Space Division for the Space Shuttle project. SERV was radically different from the two-stage spaceplanes that almost every other competitor entered into the Shuttle development process and was never given serious consideration for the shuttle program.

Douglas Aircraft's SASSTO, short for "Saturn Application Single Stage to Orbit", was a single-stage-to-orbit (SSTO) reusable launch system designed by Philip Bono's team in 1967. SASSTO was a study in minimalist designs, a launcher with the specific intent of repeatedly placing a Gemini capsule in orbit for the lowest possible cost. The SASSTO booster was based on the layout of the S-IVB upper stage from the Saturn family, modified with a plug nozzle. Although the SASSTO design was never followed up at Douglas, it is widely referred to in newer studies for SSTO launchers, notably the MBB "Beta" design, which was largely an updated version of SASSTO.

<span class="mw-page-title-main">Studied Space Shuttle designs</span> Launch vehicle study

During the lifetime of the Space Shuttle, Rockwell International and many other organizations studied various Space Shuttle designs. These involved different ways of increasing cargo and crew capacity, as well as investigating further reusability. A large focus of these designs were related to developing new shuttle boosters and improvements to the central tank, but also looked to expand NASA's ability to launch deep space missions and build modular space stations. Many of these concepts and studies would shape the concepts and programs of the 2000s such as the Constellation, Orbital Space Plane Program, and Artemis program.

<span class="mw-page-title-main">Shuttle-Centaur</span> Proposed Space Shuttle upper stage

Shuttle-Centaur was a version of the Centaur upper stage rocket designed to be carried aloft inside the Space Shuttle and used to launch satellites into high Earth orbits or probes into deep space. Two variants were developed: Centaur G-Prime, which was planned to launch the Galileo and Ulysses robotic probes to Jupiter, and Centaur G, a shortened version planned for use with United States Department of Defense Milstar satellites and the Magellan Venus probe. The powerful Centaur upper stage allowed for heavier deep space probes, and for them to reach Jupiter sooner, prolonging the operational life of the spacecraft. However, neither variant ever flew on a Shuttle. Support for the project came from the United States Air Force (USAF) and the National Reconnaissance Office, which asserted that its classified satellites required the power of Centaur. The USAF agreed to pay half the design and development costs of Centaur G, and the National Aeronautics and Space Administration (NASA) paid the other half.

References

  1. NASA - STS-117 Lift Off! ATLANTIS: "Houston, Atlantis. Roll program." Voice 1: "Roger roll, Atlantis".
  2. Gunderson, Robert; Hardy, Gordon (1966). Piloted Guidance and Control of the Saturn V Launch Vehicle. Peaceful Uses of Automation in Outer Space. Springer. pp. 33–50.
  3. Haeurssurmann, Walter (1970). Description and Performance of the Saturn Launch Vehicle's Navigation, Guidance, and Control System. 3rd International IFAC Conference on Automatic Control in Space, Toulouse. Toulouse: Elsevier. pp. 275–312.
  4. Jenks, Ken. "Why does the shuttle roll just after liftoff?".
  5. 1 2 NASA-CR-129000, TR-243-1078 (1972)