WordNet
- the (usually elliptical) path described by one celestial body in its revolution about another; "he plotted the orbit of the moon" (同)celestial orbit
- the path of an electron around the nucleus of an atom (同)electron orbit
- move in an orbit; "The moon orbits around the Earth"; "The planets are orbiting the sun"; "electrons orbit the nucleus" (同)orbit, revolve
- space in which vehicles can be parked; "there is plenty of parking behind the store"
- the act of maneuvering a vehicle into a location where it can be left temporarily
PrepTutorEJDIC
- (ロケットの)待機軌道
- (天体・人工衛星の)『軌道』;軌道の1周 / (活動・影響・知識の)範囲 / (軌道に沿って)…‘の'周りを回る / 〈人工衛星〉‘を'軌道に乗せる / 軌道に沿って回る,軌道に乗る
- 球,球体 / 天体(太陽,月,星など) / 宝珠(しゃく(scepter)とともに英国王権の象徴;十字架がついている) / 《詩》《通例複数形で》眼球;目
- 駐車 / (臨時の)駐車場;空地
- パーキン(しょうが入りの菓子パン)
Wikipedia preview
出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2014/02/03 12:08:57」(JST)
[Wiki en表示]
A parking orbit is a temporary orbit used during the launch of a satellite or other space probe. A launch vehicle boosts into the parking orbit, then coasts for a while, then fires again to enter the final desired trajectory. The alternative to a parking orbit is direct injection, where the rocket fires continuously (except during staging) until its fuel is exhausted, ending with the payload on the final trajectory.
Parking orbit for one of the early Ranger missions to the moon. Note that the launch angle varies depending on the launch time within the launch window.
Contents
- 1 Rationale for parking orbits
- 2 Disadvantages of parking orbits
- 3 Examples
- 4 References
Rationale for parking orbits[edit]
There are several reasons why a parking orbit may be used:
- It can increase the launch window. For earth-escape missions, these are often quite short (seconds to minutes) if no parking orbit is used. With a parking orbit, these can often be increased up to several hours.[1][2]
- For non-LEO missions, the desired location for the final burn may not be in a convenient spot. In particular, for earth-escape missions that want good northern coverage of the trajectory, the correct place for the final burn is often in the southern hemisphere.
- For geostationary orbit missions, the correct spot for the final (or next to final) firing is normally on the equator. In such a case, the rocket is launched, coasts in a parking orbit until it is over the equator, then fires again into a geostationary transfer orbit.[3]
- For manned lunar missions, a parking orbit allowed some checkout while still close to home, before committing to the lunar trip.[2]
- It is needed if the desired orbit has a high perigee. In this case the booster launches into an elliptical parking orbit, then coasts until a higher point in the orbit, then fires again to raise the perigee. See Hohmann transfer orbit. In this case the use of a parking orbit can also reduce the fuel usage of an inclination change, since these take less delta-V at high elevations.
The figure shows the first two reasons. For this lunar mission, the desired location for the final firing is originally over southern Africa. As the day progresses, this point stays essentially fixed while the Earth moves underneath, and this is compensated for by changing the launch angle.
Disadvantages of parking orbits[edit]
The most notable disadvantage is that a rocket needs to coast for a while, then restart while under zero g conditions. Furthermore the length of two of the burns (the initial injection burn, and the final burn) typically depend on where in the launch window the launch occurs. To do this without wasting fuel, a rocket stage that can fire, then stop, then start again as needed. This implies a liquid fuel engine since solid fuel rockets cannot be stopped or restarted - once ignited they burn to completion. But even in a liquid-fueled engine, this multiple restart capability is non-trivial for a number of reasons:
- During the coast, the propellants will drift away from the bottom of the tank and the pump inlets. This must be dealt with in some way.[4] Common methods are tanks with diaphragms, or ullage rockets for settling the propellant back to the bottom of the tank.
- Longer life batteries and other consumables are needed.
- Some engines use special chemicals for ignition; multiple sets are needed for restarts
- Better insulation is needed, particularly on cryogenic tanks, to prevent too much propellant boiloff during coast.
- A better inertial guidance system is needed, to keep track of the state during the coast.
- A reaction control system is needed, to orient the stage properly for the final burn, and perhaps to establish a suitable thermal orientation during coast.
The Centaur and Agena families of upper stages were designed for such restarts and have often been used in this manner. The last Agena flew in 1987 but Centaur is still in production. The Briz-M stage often performs the same role for Russian rockets.
Examples[edit]
- The Apollo program used parking orbits, for all the reasons mentioned above except those that pertain to geostationary orbits.[5][6]
- The Space Shuttle missions to the International Space Station did not use parking orbits, for several reasons. The station is in a high inclination Low Earth orbit, where parking orbits are not much help; the shuttle did not have multiple restart capability; and the short launch windows were not a critical problem (another one would occur a day later, due to the orbital geometry).
- On the other hand, when the shuttle launched interplanetary probes such as Galileo, it used a parking orbit to deliver the probe to the right injection spot.
- The Ariane 5 does not use parking orbits. This simplifies the launcher since multiple restart is not needed, and the penalty is small for their typical GTO mission, as their launch site is close to the equator. An upgrade to the second stage (ESC-B) will have multiple restart capability, so future missions may use parking orbits.
- In a literal example of a parking orbit, the Automated Transfer Vehicle (ATV) can park for several months in orbit while waiting to rendezvous with the International Space Station. For safety reasons, the ATV cannot approach the station while a Space Shuttle is docked or when a Soyuz or Progress are maneuvering to dock or depart.[7]
References[edit]
- ^ Hall, R. Cargill (1977). "LUNAR IMPACT - A History of Project Ranger". NASA History Series (Technical report) (National Aeronautics and Space Administration). NASA SP-4210. Retrieved 2011-11-11.
- ^ a b "Apollo Expeditions to the Moon". Chapter 3.4
- ^ Charles D. Brown. Spacecraft Mission Design. , page 83.
- ^ Krivetsky, A. and Bauer, W.H. and Loucks, H.L. and Padlog, J. and Robinson, J.V. (1962). Research on Zero-Gravity Expulsion Techniques (Technical report). Defense Technical Information Center.
- ^ "Apollo lunar landing launch window: The controlling factors and constraints". NASA.
- ^ "Apollo Flight Journal - Apollo 8, Day 1: Earth Orbit and Translunar Injection". NASA.
- ^ Stephen Clark. "Maiden launch of Europe's resupply ship gets new date". Spaceflight Now.
Articles related to orbits
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Orbits
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General |
- Box
- Capture
- Circular
- Elliptical / Highly elliptical
- Escape
- Graveyard
- Hyperbolic trajectory
- Inclined / Non-inclined
- Osculating
- Parabolic trajectory
- Parking
- Synchronous
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Geocentric |
- Geosynchronous
- Geostationary
- Sun-synchronous
- Low Earth
- Medium Earth
- High Earth
- Molniya
- Near-equatorial
- Orbit of the Moon
- Polar
- Tundra
- Two-line elements
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About other points |
- Areosynchronous
- Areostationary
- Halo
- Lissajous
- Lunar
- Heliocentric
- Heliosynchronous
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Parameters
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Shape/Size |
- Eccentricity
- Semi-major axis
- Semi-minor axis
- Apsides
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Orientation |
- Inclination
- Longitude of the ascending node
- Argument of periapsis
- Longitude of the periapsis
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Position |
- Mean anomaly
- True anomaly
- Eccentric anomaly
- Mean longitude
- True longitude
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Variation |
- Orbital period
- Mean motion
- Orbital speed
- Epoch
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Maneuvers
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- Collision avoidance (spacecraft)
- Delta-v
- Delta-v budget
- Bi-elliptic transfer
- Geostationary transfer
- Gravity assist
- Gravity turn
- Hohmann transfer
- Low energy transfer
- Oberth effect
- Inclination change
- Phasing
- Rocket equation
- Rendezvous
- Transposition, docking, and extraction
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Other orbital mechanics topics
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- Celestial coordinate system
- Characteristic energy
- Ephemeris
- Equatorial coordinate system
- Ground track
- Hill sphere
- Interplanetary Transport Network
- Kepler's laws of planetary motion
- Lagrangian point
- n-body problem
- Orbit equation
- Orbital state vectors
- Perturbation
- Retrograde motion
- Specific orbital energy
- Specific relative angular momentum
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UpToDate Contents
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English Journal
- Unexpected death following single blow to the orbit.
- Carson HJ.SourceLinn County Medical Examiner's Office, Cedar Rapids, IA 52411, USA. hjcmd@earthlink.net
- The American journal of forensic medicine and pathology.Am J Forensic Med Pathol.2010 Dec;31(4):370-2. doi: 10.1097/PAF.0b013e3181d3dbd7.
- Severe brain injury is rare after assault to the head with a fist. Our patient was a 39-year-old white male who was punched in a parking lot. The subject fell on his right head. He did not lose consciousness. The subject was taken to the hospital. On admission, his blood alcohol concentration was 22
- PMID 20216306
- Trajectory design for space missions to libration point L2.
- Di Salvo A.SourceDipartimento di Ingegneria Aerospaziale, Università degli Studi di Roma La Sapienza, Roma, Italy. alessio.disalvo@fastwebnet.it
- Annals of the New York Academy of Sciences.Ann N Y Acad Sci.2005 Dec;1065:311-24.
- This work is focused on the detection and computation of "free" transfer trajectories from parking orbits around the Earth to quasiperiodic orbits around the collinear libration point L(2), in the Sun-Earth system; no correction or insertion maneuvers into the final orbits have been considered. The
- PMID 16510417
- New trends in astrodynamics and applications: optimal trajectories for space guidance.
- Azimov D, Bishop R.SourceDepartment of Aerospace Engineering and Engineering Mechanics, The University of Texas at Austin, Austin, TX 78712, USA. azimov@mail.utexas.edu
- Annals of the New York Academy of Sciences.Ann N Y Acad Sci.2005 Dec;1065:189-209.
- This paper represents recent results on the development of optimal analytic solutions to the variation problem of trajectory optimization and their application in the construction of on-board guidance laws. The importance of employing the analytically integrated trajectories in a mission design is d
- PMID 16510410
Japanese Journal
- Design of Low Fuel Trajectory in Interior Realm as a Backup Trajectory for Lunar Exploration
- TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN 12(ists29), Pd_47-Pd_52, 2014
- NAID 130004956794
- 惑星間待機軌道を導入した自在な軌道設計手法に関する研究
- Feasibility Assessment of Nonstop Mars Sample Return System Using Aerocapture Technologies
- TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN 8(ists27), Pk_31-Pk_38, 2010
- NAID 130001080220
Related Links
- A parking orbit is a temporary orbit used during the launch of a satellite or other space probe. A launch vehicle boosts into the parking orbit, then coasts for a while, then fires again to enter the final desired trajectory. The alternative to ...
- parking orbitとは。意味や和訳。〔航空宇宙〕 パーキング軌道,駐留軌道,待機[中継]軌道:人工衛星や宇宙船をさらに遠くの軌道に乗せるために,一時的にとらせる軌道.[語源]1960 - 80万項目以上収録、例文・コロケーションが豊富な ...
★リンクテーブル★
[★]
- 軌道を回る、軌道に乗せる、~の周りを回る、~を周回する