Search NASA⌕ Search

SEARCH · Search NASA

Results for “orbit design”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
NASA NTRS2003

WMAP Observatory Thermal Design and On-Orbit Thermal Performance

The Wilkinson Microwave Anisotropy Probe (WMAP) observatory, launched June 30, 2001, is designed to measure the cosmic microwave background radiation with unprecedented precision and accuracy while orbiting the second Lagrange point (L2). The instrument cold stage must be cooled passively to <95K, and systematic thermal variations in selected instrument components controlled to less than 0.5 mK (rms) per spin period. This paper describes the thermal design and testing of the WMAP spacecraft and instrument. Flight thermal data for key spacecraft and instrument components are presented from launch through the first year of mission operations. Effects of solar flux variation due to the Earth's elliptical orbit about the sun, surface thermo-optical property degradations, and solar flares on instrument thermal stability are discussed.

Glazer, Stuart D.↗
NASA NTRS1991

Conceptual design of a two-stage-to-orbit vehicle

A conceptual design study of a two-stage-to-orbit vehicle is presented. Three configurations were initially investigated with one configuration selected for further development. The major objective was to place a 20,000-lb payload into a low Earth orbit using a two-stage vehicle. The first stage used air-breathing engines and employed a horizontal takeoff, while the second stage used rocket engines to achieve a 250-n.m. orbit. A two-stage-to-orbit vehicle seems a viable option for the next-generation space shuttle.

Source record↗
NASA NTRS1978

Applicability of the control configured design approach to advanced earth orbital transportation systems

The applicability of the control configured design approach (CCV) to advanced earth orbital transportation systems was studied. The baseline system investigated was fully reusable vertical take-off/horizontal landing single-stage-to-orbit vehicle and had mission requirements similar to the space shuttle orbiter. Technical analyses were made to determine aerodynamic, flight control and subsystem design characteristics. Figures of merit were assessed on vehicle dry weight and orbital payload. The results indicated that the major parameters for CCV designs are hypersonic trim, aft center of gravity, and control surface heating. Optimized CCV designs can be controllable and provide substantial payload gains over conventional non-CCV design vertical take-off vehicles.

Hepler, A. K.↗
NASA NTRS1979

A turbojet-boosted two-stage-to-orbit space transportation system design study

The concept to use twin turbo-powered boosters for acceleration to supersonic staging speed followed by an all rocket powered orbiter stage was proposed. A follow-on design study was then made of the concept with the performance objective of placing a 29,483 Kg payload into a .2.6 X 195.3 km orbit. The study was performed in terms of analysis and trade studies, conceptual design, utility and economic analysis, and technology assessment. Design features of the final configuration included: strakes and area rule for improved take off and low transonic drag, variable area inlets, exits and turbine, and low profile fixed landing gear for turbojet booster stage. The payload required an estimated GLOW of 1,270,000 kg for injection in orbit. Each twin booster required afterburning turbojet engines each with a static sea level thrust rating of 444,800 N. Life cycle costs for this concept were comparable to a SSTO/SLED concept except for increased development cost due to the turbojet engine propulsion system.

Hepler, A. K.↗
NASA NTRS1988

Orbital Maneuvering Vehicle space station communications design

The authors present an Orbital Maneuvering Vehicle space station communications systems design approach which is intended to satisfy the stringent link requirements. The operational scenario, system configuration, signal design, antenna system management, and link performance analysis are discussed in detail. It is shown that the return link can transmit up to 21.6 Mb/s and maintain at least a 3-dB link margin through proper power and antenna management control at a maximum distance of 37 km. It is suggested that the proposed system, which is compatible with the space station multiple-access system, can be a model for other space station interoperating elements or users to save the development cost and reduce the technical and schedule risks.

Arndt, D.↗
NASA NTRS2006

Design and "As Flown" Radiation Environments for Materials in Low Earth Orbit

A conservative design approach was adopted by the International Space Station Program for specifying total ionizing radiation dose requirements for use in selecting and qualifying materials for construction of the International Space Station. The total ionizing dose design environment included in SSP 30512 Space Station Ionizing Radiation Design Environment is based on trapped proton and electron fluence derived from the solar maximum versions of the AE-8 and AP-8 models, respectively, specified for a circular orbit at 500 km altitude and 51.7 degree inclination. Since launch, the range of altitudes utilized for Space Station operations vary from a minimum of approximately 330 km to a maximum of approximately 405 km with a mean operational altitude less than 400 km. The design environment, therefore, overestimates the radiation environment because the particle flux in the South Atlantic Anomaly is the primary contributor to radiation dose in low Earth orbit and flux within the Anomaly is altitude dependent. In addition, a 2X multiplier is often applied to the design environment to cover effects from the contributions of galactic cosmic rays, solar energetic particle events, geomagnetic storms, and uncertainties in the trapped radiation models which are not explicitly included in the design environment. Application of this environment may give radiation dose overestimates on the order of 1OX to 30X for materials exposed to the space environment, suggesting that materials originally qualified for ten year exposures on orbit may be used for longer periods without replacement. In this paper we evaluate the "as flown" radiation environments derived from historical records of the ISS flight trajectory since launch and compare the results with the SSP 30512 design environment to document the magnitude of the radiation dose overestimate provided by the design environment. "As flown" environments are obtained from application of the AE-8/AP-8 trapped particle models along the ISS flight trajectory including variations in altitude due to decay of the vehicle orbit and periodic reboosts to higher altitudes. In addition, an estimate of the AE-8 model to predict low Earth orbit electron flux (because the radiation dose for thin materials is dominated by the electron component of the radiation environment) is presented based on comparisons of the AE-8 model to measurements of electron integral flux at approximately 850 km from the Medium Energy Proton and Electron Detector on board the NOAA Polar Operational Environmental Satellite.

Minow, Joseph↗
NASA NTRS2003

Optical Designs for a Solar Orbiter EUV Imager

An EUV Imager is baselined as one of the remote sensing instruments onboard the Solar Orbiter mission now being planned by ESA. The performance goals for this instrument may be achieved by a specialized 'slitless spectrograph' design, which could offer EUV spectroscopic information as an added bonus. I will discuss my studies of such a design, tailored for the Solar Orbiter scientific objectives and scaled to the available payload envelope. Some of the trade-offs required in terms of sensitivity, field-of-view, and spatial resolution will be described, so that the science team can make optimized choices from the full range of possible optical-design solutions.

Thomas, Roger J.↗
NASA NTRS1991

Conceptual design of two-stage-to-orbit hybrid launch vehicle

The object of this design class was to design an earth-to orbit vehicle to replace the present NASA space shuttle. The major motivations for designing a new vehicle were to reduce the cost of putting payloads into orbit and to design a vehicle that could better service the space station with a faster turn-around time. Another factor considered in the design was that near-term technology was to be used. Materials, engines and other important technologies were to be realized in the next 10 to 15 years. The first concept put forth by NASA to meet these objectives was the National Aerospace Plane (NASP). The NASP is a single-stage earth-to-orbit air-breathing vehicle. This concept ran into problems with the air-breathing engine providing enough thrust in the upper atmosphere, among other things. The solution of this design class is a two-stage-to-orbit vehicle. The first stage is air-breathing and the second stage is rocket-powered, similar to the space shuttle. The second stage is mounted on the top of the first stage in a piggy-back style. The vehicle takes off horizontally using only air-breathing engines, flies to Mach six at 100,000 feet, and launches the second stage towards its orbital path. The first stage, or booster, will weigh approximately 800,000 pounds and the second stage, or orbiter will weigh approximately 300,000 pounds. The major advantage of this design is the full recoverability of the first stage compared with the present solid rocket booster that are only partially recoverable and used only a few times. This reduces the cost as well as providing a more reliable and more readily available design for servicing the space station. The booster can fly an orbiter up, turn around, land, refuel, and be ready to launch another orbiter in a matter of hours.

Source record↗
NASA NTRS2018

Design and On-Orbit Operation of the Adiabatic Demagnetization Refrigerator on the Hitomi Soft X-Ray Spectrometer Instrument

The Soft X-ray Spectrometer instrument on the Astro-H observatory contains a 6x6 array of x-ray microcalorimeters that is cooled to 50 mK by an adiabatic demagnetization refrigerator (ADR). The ADR consists of three stages in order to provide stable detector cooling using either a 1.2 K superfluid helium bath or a 4.5 K Joule-Thomson (JT) cryocooler as its heat sink. When liquid helium is present, two of the ADR's stages are used to single-shot cool the detectors while rejecting heat to the helium. After the helium is depleted, all three stages are used to continuously cool the helium tank (to about 1.5 K) and single-shot cool the detectors (to 50 mK), using the JT cryocooler as its heat sink. The Astro-H observatory, renamed Hitomi after its successful launch in February 2016, carried approximately 36 liters of helium into orbit. On day 5, the helium had cooled sufficiently (<1.4 K) to allow operation of the ADR. This paper describes the design, operation and on-orbit performance of the ADR, and the use of the ADR's heat rejection as a tool for mass gauging the helium tank.

adiabatic demagnetization refrigerator↗
NASA NTRS1985

The aerodynamic challenges of the design and development of the space shuttle orbiter

The major aerodynamic design challenge at the beginning of the United States Space Transportation System (STS) research and development phase was to design a vehicle that would fly as a spacecraft during early entry and as an aircraft during the final phase of entry. The design was further complicated because the envisioned vehicle was statically unstable during a portion of the aircraft mode of operation. The second challenge was the development of preflight aerodynamic predictions with an accuracy consistent with conducting a manned flight on the initial orbital flight. A brief history of the early contractual studies is presented highlighting the technical results and management decisions influencing the aerodynamic challenges. The configuration evolution and the development of preflight aerodynamic predictions will be reviewed. The results from the first four test flights shows excellent agreement with the preflight aerodynamic predictions over the majority of the flight regimes. The only regimes showing significant disagreement is confined primarily to early entry, where prediction of the basic vehicle trim and the influence of the reaction control system jets on the flow field were found to be deficient. Postflight results are analyzed to explain these prediction deficiencies.

Young, J. C.↗
NASA NTRS2002

Trajectory design for the Mars Reconnaissance Orbiter Mission

This paper describes the analysis and design evolution of the Mars Reconnaissance Orbiter trajectory from launch to end-of-mission. The mission uses a combination of propulsive maneuvers and aerobraking techniques to deliver the orbiter to a low-altitude frozen orbit at Mars. The launch/arrival space for the 2005 Earth-Mars opportunity will be described as well as the particular launch strategy chosen for this mission. Details of the aerobraking profile will be provided. Finally, the Primary Science Orbit will be examined, and the trade-offs between science objectives and orbiter capability will be presented.

Mars↗
NASA NTRS1980

A survey of load methodologies for shuttle orbiter payloads

Loads methods currently being used to design shuttle orbiter payloads are summarized. Methods used for the design of payloads launched by expendable launch vehicles are described in historical perspective. Experiences gained from expendable launch vehicle payloads are used to develop methodologies for the space shuttle orbiter payloads. The objectives for the development of a new methodology for the shuttle payloads are to reduce the cost and schedule for the payload load analysis by decoupling the payload analysis from the launch vehicle to the maximum extent possible. Methods are described for payload member load estimation or obtaining upper bounds for dynamic loads, as well as load prediction or calculating actual transient member load time histories.

Chen, J. C.↗
NASA NTRS1977

Intelsat battery and power system design

The orbit data for the Intelsat 4 spacecraft is described. The performance and characteristics of the battery used for this spacecraft are discussed. Graphs are presented which relate battery voltage to various eclipse seasons.

Dunlop, J. D.↗
NASA NTRS1982

Space Shuttle autoland design

The Orbiter Autoland system is activated at 10,000 ft altitude and performs energy control through speedbrake modulation, vertical path tracking with acceleration commands to the pitch control system, lateral path tracking through bank angle commands to the roll control system, and brings the vehicle to main gear touchdown. A nominal 19 degree glide slope is flown down to 2000 ft, followed by a 1.5 deg path to flare and subsequent soft landing. The flight path is similar to that which a pilot would fly, a feature which increases safety factors should manual takeover be necessary during landing maneuvers. A block diagram of the autoland control interfaces is provided, and attention is given to the use of a reference trajectory, the guidance laws, lateral guidance, the speed control system, pitch rate control, and the rollout system. Conditions and instrument indications leading to pilot takeover are outlined.

Tsikalas, G. M.↗
NASA NTRS1983

An engineering evaluation of the Space Shuttle OMS engine after 5 orbital flights

Design features, performances on the first five flights, and condition of the Shuttle OMS engines are summarized. The engines were designed to provide a vacuum-fed 6000 lb of thrust and a 310 sec specific impulse, fueled by a combination of N2O4 and monomethylhydrazine (MMH) at a mixture ratio of 1.65. The design lifetime is 1000 starts and 15 hr of cumulative firing duration. The engine assembly is throat gimballed and features yaw actuators. No degradation of the hot components was observed during the first five flights, and the injector pattern maintained a uniform, enduring level of performance. An increase in the take-off loads have led to enhancing the wall thickness in the nozzle in affected areas. The engine is concluded to be performing to design specifications and is considered an operational system.

David, D.↗