Editing Geostationary transfer orbit (section)

==Other considerations==

Even at apogee, the fuel needed to reduce inclination to zero can be significant, giving equatorial launch sites a substantial advantage over those at higher latitudes. [[Russia]]'s [[Baikonur Cosmodrome]] in [[Kazakhstan]] is at 46° north latitude. [[Kennedy Space Center]] in the [[United States]] is at 28.5° north. [[China]]'s [[Wenchang Space Launch Site|Wenchang]] is at 19.5° north. [[India]]'s [[Satish Dhawan Space Centre|SDSC]] is at 13.7° north. [[Guiana Space Centre]], the European [[Ariane (rocket family)|Ariane]] and European-operated Russian [[Soyuz (rocket family)|Soyuz]] launch facility, is at [[5th parallel north|5° north]]. The "indefinitely suspended" [[Sea Launch]] launched from a floating platform directly on the equator in the [[Pacific Ocean]].

[[Expendable launch system|Expendable]] launchers generally reach GTO directly, but a spacecraft already in a low Earth orbit ([[Low Earth orbit|LEO]]) can enter GTO by firing a [[rocket]] along its orbital direction to increase its velocity. This was done when geostationary spacecraft were launched from the [[Space Shuttle]]; a "perigee kick motor" attached to the spacecraft ignited after the shuttle had released it and withdrawn to a safe distance.

Although some launchers can take their payloads all the way to geostationary orbit, most end their missions by releasing their payloads into GTO. The spacecraft and its operator are then responsible for the maneuver into the final geostationary orbit.  The 5-hour coast to first apogee can be longer than the battery lifetime of the launcher or spacecraft, and the maneuver is sometimes performed at a later apogee or split among multiple apogees. The solar power available on the spacecraft supports the mission after launcher separation. Also, many launchers now carry several satellites in each launch to reduce overall costs, and this practice simplifies the mission when the payloads may be destined for different orbital positions.

Because of this practice, launcher capacity is usually quoted as spacecraft mass to GTO, and this number will be higher than the payload that could be delivered directly into GEO.

For example, the capacity (adapter and spacecraft mass) of the [[Delta IV Heavy]] is 14,200&nbsp;kg to GTO, or 6,750&nbsp;kg directly to geostationary orbit.<ref name=":0">United Launch Alliance, ''Delta IV Launch Services User's Guide'' June 2013, p. 2-10, Figure 2-9; {{cite web|url=http://www.ulalaunch.com/site/docs/product_cards/guides/Delta%20IV%20Users%20Guide%20June%202013.pdf |title=Archived copy |access-date=2013-10-14 |url-status=dead |archive-url=https://web.archive.org/web/20131014123330/http://www.ulalaunch.com/site/docs/product_cards/guides/Delta%20IV%20Users%20Guide%20June%202013.pdf |archive-date=2013-10-14 }} accessed 2013 July 27.</ref>

If the maneuver from GTO to GEO is to be performed with a single impulse, as with a single solid-rocket motor, apogee must occur at an equatorial crossing and at synchronous orbit altitude. This implies an argument of perigee of either 0° or 180°. Because the argument of perigee is slowly perturbed by the [[Flattening|oblateness]] of the Earth, it is usually biased at launch so that it reaches the desired value at the appropriate time (for example, this is usually the sixth apogee on [[Ariane 5]] launches<ref>ArianeSpace, ''Ariane 5 User's Manual'' Issue 5 Revision 1, 2011 July, p. 2-13, {{cite web |url=http://www.arianespace.com/wp-content/uploads/2015/09/Ariane5_users_manual_Issue5_July2011.pdf |title=Archived copy |access-date=2016-03-08 |url-status=dead |archive-url=https://web.archive.org/web/20160309022120/http://www.arianespace.com/wp-content/uploads/2015/09/Ariane5_users_manual_Issue5_July2011.pdf |archive-date=2016-03-09 }} accessed 8 March 2016.</ref>). If the GTO inclination is zero, as with [[Sea Launch]], then this does not apply. (It also would not apply to an impractical GTO inclined at 63.4°; see [[Molniya orbit]].)

The preceding discussion has primarily focused on the case where the transfer between LEO and GEO is done with a single intermediate transfer orbit.  More complicated trajectories are sometimes used. For example, the [[Proton-M]] uses a set of three intermediate orbits, requiring five upper-stage rocket firings, to place a satellite into GEO from the high-inclination site of [[Baikonur Cosmodrome]], in [[Kazakhstan]].<ref>International Launch Services, [http://www.ilslaunch.com/sites/default/files/pdf/Proton%20Mission%20Planner%27s%20Guide%20Revision%207%20%28LKEB-9812-1990%29.pdf ''Proton Mission Planner's Guide''] Rev. 7 2009 November, p. 2-13, Figure 2.3.2-1, accessed 2013 July 27.</ref>  Because of Baikonur's high latitude and range safety considerations that block launches directly east, it requires less delta-v to transfer satellites to GEO by using a [[Supersynchronous orbit|supersynchronous transfer orbit]] where the apogee (and the maneuver to reduce the transfer orbit inclination) are at a higher altitude than 35,786&nbsp;km, the geosynchronous altitude.  Proton even offers to perform a supersynchronous apogee maneuver up to 15 hours after launch.<ref>International Launch Services, [http://www.ilslaunch.com/sites/default/files/pdf/Proton%20Mission%20Planner%27s%20Guide%20Revision%207%20%28LKEB-9812-1990%29.pdf ''Proton Mission Planner's Guide''] Rev. 7 2009 November, accessed 2013 July 27 Appendix F.4.2, page F-8.</ref>

The geostationary orbit is a special type of orbit around the Earth in which a satellite orbits the planet at the same rate as the Earth's rotation. This means that the satellite appears to remain stationary relative to a fixed point on the Earth's surface. The geostationary orbit is located at an altitude of approximately 35,786 kilometers (22,236 miles) above the Earth's equator.