Editing Mariner 10 (section)

=== Departing Earth ===
[[File:Atlas-Centaur launch with Mariner 10.jpg|thumb|200px|right|Launch of ''Mariner 10'']]

Boeing finished building the spacecraft at the end of June 1973, and ''Mariner 10'' was delivered from Seattle to JPL's headquarters in California, where JPL comprehensively tested the integrity of the spacecraft and its instruments. After the tests were finished, the probe was transported to the [[Eastern Test Range]] in Florida, the launch site. Technicians filled a tank on the spacecraft with {{convert|29|kg}} of hydrazine fuel so that the probe could make course corrections, and attached [[Squib (explosive)|squibs]], whose detonation would signal ''Mariner 10'' to exit the launch rocket and deploy its instruments.{{sfn|Dunne|Burgess|1978|p=42}}{{sfn|Murray|Burgess|1977|pp=36-37}} The planned gravity assist at Venus made it feasible to use an [[Atlas-Centaur]] rocket instead of a more powerful but more expensive [[Titan IIIC]].<ref name="Paul" />{{sfn|Strom|Sprague|2003|pp=14-16}} The probe and the Atlas-Centaur were attached together ten days prior to liftoff. Launch posed one of the largest risks of failure for the ''Mariner 10'' mission; [[Mariner 1]], [[Mariner 3]], and [[Mariner 8]] all failed minutes after lift-off due to either engineering failures or Atlas rocket malfunctions.{{sfn|Murray|Burgess|1977|p=38}}<ref name="nssdc2" /><ref name="spokesman1" /> The mission had a launch period of about a month in length, from 16 October 1973, to 21 November 1973. NASA chose 3 November as the launch date because it would optimize imaging conditions when the spacecraft arrived at Mercury.{{sfn|Strom|Sprague|2003|pp=14-16}}

On 3 November at 17:45 UTC, the Atlas-Centaur carrying ''Mariner 10'' lifted off from pad [[Spaceport Florida Launch Complex 36|SLC-36B]].<ref name=nssdc3/> The Atlas stage burned for around four minutes, after which it was jettisoned, and the Centaur stage took over for an additional five minutes, propelling ''Mariner 10'' to a [[parking orbit]]. The temporary orbit took the spacecraft one-third of the distance around Earth: this maneuver was needed to reach the correct spot for a second burn by the Centaur engines, which set ''Mariner 10'' on a path towards Venus. The probe then separated from the rocket; subsequently, the Centaur stage diverted away to avoid the possibility of a future collision. Never before had a planetary mission depended upon two separate rocket burns during the launch, and even with ''Mariner 10'', scientists initially viewed the maneuver as too risky.<ref name=Bowles/>{{sfn|Dunne|Burgess|1978|pp=45-46}}

During its first week of flight, the ''Mariner 10'' camera system was tested by taking five [[Panoramic photography|photographic mosaics]] of the [[Earth]] and six of the [[Moon]]. It also obtained photographs of the north polar region of the Moon where prior coverage was poor. These photographs provided a basis for cartographers to update lunar maps and improve the [[Selenographic coordinates|lunar control net]].{{sfn|Dunne|Burgess|1978|pp=47-53}}<gallery>
File:Earth by Mariner10.jpg|Mosaic of Earth by images taken during Mariner 10 departure from Earth-Moon system.
File:PIA02442 Moon's North Pole.jpg|Moon's North Pole - This mosaic is composed of 22 frames acquired in orange (15), clear (4), UV (2), and UV-polarized (1) wavelengths.
File:Earth Mariner 10 - 0147-0200 1973-309 (23729635796).png|8-frame mosaic of the Earth, acquired on November 5, 1973. Mariner 10 was approximately 200,000 km (120,000 mi) from the Earth.
File:Earth - Mariner 10 (23681954686).png|3-frame Mariner 10 mosaic of Earth, taken November 6, 1973 through the spacecraft's Minus UV filter. 
File:Earth & Moon by Mariner 10.jpg|The Earth and Moon  from 2.6 million km. These images have been combined at right to illustrate the relative sizes of the two bodies. 
</gallery>