Editing Apollo 9 (section)

== Mission highlights ==
=== First through fifth days (March 3–7) ===
[[File:Apollo-9-Lancering.jpg|thumb|upright|alt=A rocket blasts off|Apollo{{nbsp}}9 launches from [[Kennedy Space Center]], March 3, 1969]]

Originally scheduled to launch on February 28, 1969, the liftoff of Apollo{{nbsp}}9 was postponed because all three astronauts had colds, and NASA did not want to risk that the mission might be affected. Around-the-clock labor shifts were required to keep the spacecraft in readiness; the delay cost $500,000.{{sfn|''Science News'' 1969-03-15|p=255}} The rocket launched from KSC at 11:00:00 EST (16:00:00 GMT) on March 3.{{sfn|Mission Report|p=1-1}} This was well within the launch window, which would have remained open for another three and a quarter hours.{{sfn|Orloff & Harland|p=224}} Present in the firing control room was Vice President [[Spiro Agnew]] on behalf of the new [[Richard Nixon|Nixon]] administration.<ref name="chariots_apollonine">[[#Brooks, et al.|Brooks, et al. 1979]], Chapter 12.5: [https://www.hq.nasa.gov/office/pao/History/SP-4205/ch12-5.html "Apollo 9: Earth orbital trials"] ({{Webarchive|url=https://web.archive.org/web/20111027200206/http://www.hq.nasa.gov/office/pao/History/SP-4205/ch12-5.html |date=October 27, 2011 }})</ref>

McDivitt reported a smooth ride during the launch, although there was some vibration and the astronauts were surprised to be pushed forward when the Saturn V's first stage stopped firing, before its second stage took over, when they were pushed back into their couches.<ref name="chariots_apollonine" /> Each of the first two stages slightly underperformed; a deficiency made up, more or less, by the [[S-IVB]] third stage.{{sfn|Mission Report|p=7-1}} Once the third stage cut out at 00:11:04.7 into the mission,{{sfn|Mission Report|p=3-4}} Apollo{{nbsp}}9 had entered a parking orbit of {{convert|102.3|by|103.9|mi}}.{{sfn|Mission Report|p=1-1}}

The crew began their first major orbital task with the separation of the CSM from the S-IVB at 02:41:16 into the mission, seeking to turn around and then dock with the LM, which was on the end of the S-IVB, after which the combined spacecraft would separate from the rocket. If it was not possible to perform such a docking on a later mission, a lunar landing could not take place. It was Scott's responsibility to fly the CSM, which he did to a successful docking, as the probe-and-drogue docking assembly worked properly. After McDivitt and Schweickart inspected the tunnel connecting the CM and LM, the assembled spacecraft separated from the S-IVB. The next task was to demonstrate that two docked spacecraft could be maneuvered by one engine. A five-second burn took place at 05:59.01.1 into the mission, accomplished with the SM's [[Service Propulsion System]] (SPS), after which Scott excitedly reported the LM was still in place. The S-IVB was fired again to send itself into solar orbit.<ref name="chariots_apollonine" />{{sfn|Mission Report|p=3-4}}

[[File:Apolo-1. CSM&LM diagram.svg|thumb|500px|left|alt=labeled drawing of two docked spacecraft|Apollo spacecraft configuration with CSM (right) and LM docked<br>
'''I''' - Lunar module descent stage; '''II''' - Lunar module ascent stage; '''III''' - Command module; '''IV''' - Service module.<br>
'''1''' LM descent engine skirt; '''2''' LM landing gear; '''3''' LM ladder; '''4''' Egress platform; '''5''' Forward hatch; '''6''' LM reaction control system quad; '''7''' S-band inflight antenna (2); '''8''' Rendezvous radar antenna; '''9''' S-band steerable antenna; '''10''' Command Module crew compartment; '''11''' Electrical power system radiators; '''12''' SM reaction control system quad; '''13''' Environmental control system radiator; '''14''' S-band steerable]]

From 09:00:00 to 19:30:00, a sleep period was scheduled.{{sfn|Mission Report|pp=3-6–3-7}} The astronauts slept well, but complained of being woken by non-English transmissions. Scott theorized that they were possibly in Chinese.<ref>{{cite web|url=https://historycollection.jsc.nasa.gov/JSCHistoryPortal/history/mission_trans/AS09_TEC.PDF |archive-url=https://ghostarchive.org/archive/20221009/https://historycollection.jsc.nasa.gov/JSCHistoryPortal/history/mission_trans/AS09_TEC.PDF |archive-date=2022-10-09 |url-status=live|title=Apollo 9 Technical Air-to-Ground Voice Transcription|date=March 1969|location=Houston, Texas|page=76|publisher=NASA}}</ref> The highlight of the second day in orbit (March 4) was three SPS burns.<ref name = "NYT March 5">{{cite news|url=https://www.nytimes.com/1969/03/05/archives/apollo-9-proves-its-linkup-is-firm-combined-craft-and-lunar-module.html |url-access=subscription|last=Wilford|first=John Noble|author-link=John Noble Wilford|title=Apollo 9 proves its linkup is firm|date=March 5, 1969|newspaper=[[The New York Times]]|pages=1, 20}}</ref> The initial burn, at 22:12:04.1,{{sfn|Mission Report|p=3-4}} lasted 110 seconds,<ref name = "NYT March 5" /> and including swiveling or "gimbaling" the engine to test whether the autopilot could dampen the induced oscillations, which it did within five seconds. Two more SPS burns followed, lightening the SM's fuel load.<ref name="chariots_apollonine" /> The spacecraft and engine passed every test, sometimes proving more robust than expected.{{sfn|French & Burgess|p=343}} The performance of the CSM in remaining stable while the engine was being gimbaled would, in 1972, help McDivitt, by then manager of the Apollo Spacecraft Program, to approve the continuation of the [[Apollo 16]] mission when its CSM experienced an unstable gimbal after separation from its LM in lunar orbit.{{sfn|Chaikin|pp=461–462}}

The flight plan for the third day was to have the commander and lunar module pilot enter the LM to check out its systems and use its [[descent propulsion system|descent engine]] to move the entire spacecraft.{{sfn|Press Kit|pp=3–4}} The descent engine was the backup to the SPS; the ability to use it in this manner later proved critical during the [[Apollo 13]] mission.{{sfn|Chaikin|pp=298–301}} The flight plan was thrown into question when Schweickart, suffering from [[space adaptation sickness]], vomited, while McDivitt felt queasy as well. They had been avoiding sudden physical motions, but the contortion-like maneuvers to don their space suits for the LM checkout caused them to feel ill. The experience taught the doctors enough about the sickness to have astronauts avoid it during the lunar landings but, at the time, Schweickart feared his vomiting might endanger President Kennedy's goal. They were well enough to continue and entered the LM, thus transferring between vehicles for the first time in the US space program, and making the first transfer without needing to spacewalk, as Soviet cosmonauts had done. The hatches were then closed, though the modules remained docked, showing that ''Spider''{{'s}} communications and life support systems would work in isolation from those of ''Gumdrop''. On command, the landing legs sprang into the position they would assume for landing on the Moon.{{sfn|French & Burgess|pp=344–345}}

[[File:Schweickart Apollo 9 EVA (AS09-19-2982).jpg|thumb|right|alt=Spacesuited man in orbit by spacecraft|Schweickart during his EVA, photographed by Scott standing up in the command module hatch]]

In the LM, Schweickart vomited again, causing McDivitt to request a private channel to the doctors in Houston. The first episode had not been reported to the ground because of its brief nature, and when the media learned what had happened to Schweickart, there were "repercussions and a spate of unfriendly stories".<ref name="chariots_apollonine" /> They finished the LM checkout, including the successful firing of the descent engine, and returned to Scott in ''Gumdrop''.<ref name="chariots_apollonine" /> The burn lasted 367 seconds and simulated the throttle pattern to be used during the landing on the Moon.<ref name = "nasa nine" /> After they returned, a fifth firing of the SPS was made, designed to circularize Apollo{{nbsp}}9's orbit in preparation for the rendezvous.{{sfn|Mission Report|p=3-1}} This took place at 54:26:12.3,{{sfn|Mission Report|p=3-4}} raising the craft's orbit to {{convert|142|by|149|mi}}.<ref name = "nasa nine">{{cite web|title=Apollo 9|url=https://www.nasa.gov/mission_pages/apollo/missions/apollo9.html|publisher=[[NASA]]|date=July 8, 2009|access-date=April 2, 2019}}</ref>

The fourth day's program (March 6) was for Schweickart to exit the hatch on the LM and make his way along the outside of the spacecraft to the CM's hatch, where Scott would stand by to assist, demonstrating that this could be done in the event of an emergency. Schweickart was to wear the life support backpack, or [[Primary Life Support System|PLSS]], to be worn on the lunar surface EVAs.{{sfn|Press Kit|pp=4–5}} This was the only EVA scheduled before the lunar landing, and thus the only opportunity to test the PLSS in space. McDivitt initially canceled the EVA due to Schweickart's condition, but with the lunar module pilot feeling better, decided to allow him to exit the LM, and once he was there, to move around the LM's exterior using handholds. Scott stood in the CM's hatch; both men photographed each other and retrieved experiments from the exterior of their vehicles. Schweickart found moving around easier than it had been in simulations; both he and Scott were confident that Schweickart could have completed the exterior transfer if called upon to do so, but considered it unnecessary.<ref name="chariots_apollonine" /><ref name="chariots_overview">[[#Brooks, et al.|Brooks, et al. 1979]], Chapter 12.4: [https://www.hq.nasa.gov/office/pao/History/SP-4205/ch12-4.html "The mission and the men"] ({{Webarchive|url=https://web.archive.org/web/20210428014236/https://www.hq.nasa.gov/office/pao/History/SP-4205/ch12-4.html |date=April 28, 2021 }}).</ref> During the EVA, Schweickart used the call sign "Red Rover", a nod to the color of his hair.<ref name = "rover" />

[[File:Spider in Earth Orbit - GPN-2000-001106.jpg|thumb|left|alt=The LM in flight, Earth seen|Apollo 9 LM ''Spider'']]

On March 7, the fifth day, came "the key event of the entire mission: the separation and rendezvous of the lunar module and the command module".<ref name="chariots_apollonine" /> The lunar module lacked the capability to return the astronauts to Earth;{{sfn|''Science News'' 1969-03-01|p=218}} this was the first time space travelers had flown in a vehicle that could not take them home.<ref name = "rover">{{cite web|title=50 years ago: ''Spider'', ''Gumdrop'', and Red Rover in space|publisher=[[NASA]]|date=March 6, 2019|access-date=May 3, 2019|url=https://www.nasa.gov/feature/50-years-ago-spider-gumdrop-and-red-rover-in-space}}</ref> McDivitt and Schweickart entered the LM early, having obtained permission to do so without wearing their helmets and gloves, making it easier to set up the LM.<ref name="chariots_apollonine" /> When Scott in ''Gumdrop'' pushed the button to release the LM, it initially hung on the latches at the end of the docking probe, but he hit the button again and ''Spider'' was released.{{sfn|French & Burgess|pp=349–350}} After spending about 45 minutes near ''Gumdrop'', ''Spider'' went into a slightly higher orbit, meaning that over time, the two craft would separate, with ''Gumdrop'' ahead.<ref name="chariots_apollonine" /> Over the next hours, McDivitt fired the LM's descent engine at several throttle settings; by the end of the day the LM was thoroughly test-flown.{{sfn|French & Burgess|pp=350–351}} At a distance of {{convert|185|km|sp=us|order=flip}}, ''Spider'' fired to lower its orbit and thus began to catch up with ''Gumdrop'', a process that took over two hours, and the descent stage was jettisoned.<ref name="chariots_apollonine" />

[[File:Interior of Gumdrop (AS09-20-3104).jpg|thumb|right|alt=Inside view of CM|The interior of ''Gumdrop'']]
The approach and rendezvous were conducted as near as possible to what was planned for the lunar missions. To demonstrate that rendezvous could be performed by either craft, ''Spider'' was the active party during the maneuver.{{sfn|French & Burgess|pp=351–352}} McDivitt brought ''Spider'' close to ''Gumdrop'', then maneuvered the LM to show each side to Scott, allowing him to inspect for any damage. Then, McDivitt docked the craft.<ref name="chariots_apollonine" /> Due to glare from the Sun, he had trouble doing this and Scott guided him in. During the later missions, the job of docking the two spacecraft in lunar orbit would fall to the command module pilot.{{sfn|French & Burgess|p=352}} After McDivitt and Schweickart returned to ''Gumdrop'', ''Spider'' was jettisoned, its engine fired remotely to fuel depletion by Mission Control as part of further testing of the engine,<ref name = "nasa nine" /><ref name="chariots_apollonine" /> simulating an ascent stage's climb from the lunar surface. This raised ''Spider'' to an orbit with [[apogee]] of over {{convert|3700|nmi}}.{{sfn|''Science News'' 1969-03-22a|p=277}} The only major lunar module system not fully tested was the landing radar, as this could not be done in Earth orbit.{{sfn|''Science News'' 1969-03-22a|pp=277–278}}

=== Sixth through eleventh days (March 8–13) ===
[[File:Apollo 9 approaches splashdown.jpg|thumb|left|alt=Spaceship descends over ocean with parachutes|Apollo 9 approaches [[splashdown (spacecraft landing)|splashdown]] in the [[Atlantic Ocean]], March 13, 1969]]

Apollo 9 was to remain in space for about ten days to check how the CSM would perform over the period of time required for a lunar mission.{{sfn|French & Burgess|p=352}} Most major events had been scheduled for the first days so that they would be accomplished if the flight needed to be ended early.{{sfn|Orloff & Harland|p=223}} The remaining days in orbit were to be conducted at a more leisurely pace.{{sfn|Press Kit|pp=2, 6}} With the main goals of the mission accomplished, the hatch window was used for special photography of Earth, using four identical [[Hasselblad]] cameras, coupled together and using film sensitive to different parts of the [[electromagnetic spectrum]].<ref name=nasa>{{cite book|editor-last=Nicks|editor-first=Oran W.|title=This Island Earth|publisher=[[NASA]]|year=1970|pages=100–101}}</ref> Such photography allowed different features of the Earth's surface to appear, for example, tracking of water pollution as it exits mouths of rivers into the sea,{{sfn|''Science News'' 1969-03-15|p=255}} and the highlighting of agricultural areas using [[infrared]].<ref name=nasa/> The camera system was a prototype, and would pave the way for the [[Earth Resources Technology Satellite]], predecessor to the [[Landsat]] series.{{sfn|Harland|p=335}} The photography was successful, as the ample time in orbit meant the crew could wait to allow cloud cover to pass, and would inform [[Skylab]]'s mission planning.{{sfn|Orloff & Harland|p=230}}

Scott used a [[sextant]] to track landmarks on the Earth, and turned the instrument to the skies to observe the planet Jupiter, practicing navigation techniques that were to be used on later missions.<ref name = "NYT March 10">{{cite news|last=Wilford|first=John Noble|author-link=John Noble Wilford|url=https://www.nytimes.com/1969/03/10/archives/the-apollo-9-astronauts-take-a-restful-cruise-through-space.html|title=The Apollo 9 astronauts take a restful cruise through space|date=March 10, 1969|newspaper=[[The New York Times]]|page=40|url-access=subscription}}</ref> The crew was able to track the [[Pegasus 3]] satellite (launched in 1965) as well as the ascent stage of ''Spider''.{{sfn|Orloff & Harland|p=230}} The sixth burn of the SPS engine took place on the sixth day, though it was postponed one orbit as the [[reaction control system]] (RCS) thruster burn needed to [[Ullage#Rocketry|settle the reactants in their tanks]] was not properly programmed. The SPS burn lowered the perigee of Apollo{{nbsp}}9's orbit,{{sfn|Mission Report|p=3-2}} allowing for improved RCS thruster deorbit capability as a backup to the SPS.{{sfn|Press Kit|pp=6, 22}}

[[File:The Apollo 9 Command Module (CM).jpg|thumb|right|alt=A spacecraft is lifted in the air onto a ship|''Gumdrop'' is hoisted aboard the USS ''Guadalcanal'']]

Considerable testing of the CSM took place, but this was principally Scott's responsibility, allowing McDivitt and Schweickart leisure to observe the Earth; they alerted Scott if anything particularly noteworthy was upcoming, letting him leave his work for a moment to look at Earth too.{{sfn|French & Burgess|pp=352–353}} The seventh burn of the SPS system took place on the eighth day, March 10; its purpose was again to aid RCS deorbit capability, as well as extending ''Gumdrop''{{'s}} orbital lifetime. It shifted the apogee of the orbit to the Southern Hemisphere, allowing for a longer free-fall time to entry when Apollo{{nbsp}}9 returned to Earth. The burn was extended to allow for testing of the propellent gaging system, which had been behaving anomalously during earlier SPS burns.{{sfn|Mission Report|p=3-2}}{{sfn|Press Kit|p=22}} Once it was accomplished, Apollo{{nbsp}}9's RCS thrusters could have returned it to Earth and still allowed it to land in the primary recovery zone had the SPS engine failed. The eighth and final SPS burn, to return the vehicle to Earth, was accomplished on March&nbsp;13, less than an hour after the ten-day mark of the mission, after which the service module was jettisoned. The landing was delayed one orbit because of unfavorable weather in the primary landing zone{{sfn|Mission Report|p=7-4}} some {{convert|220|nmi}} ESE of Bermuda.{{sfn|Press Kit|p=7}}<ref name=clss>{{cite news |url=https://news.google.com/newspapers?id=9GxYAAAAIBAJ&sjid=EvgDAAAAIBAJ&pg=6683%2C3180989 |work=Spokane Daily Chronicle |location=(Washington) |agency=Associated Press |title=Capsule's landing sight shifted |date=March 12, 1969 |page=1}}</ref><ref name=mapsite>{{cite news |url=https://news.google.com/newspapers?id=9GxYAAAAIBAJ&sjid=EvgDAAAAIBAJ&pg=5651%2C3217879 |work=Spokane Daily Chronicle |location=(Washington) |agency=AP map |title=Splashdown sites |date=March 12, 1969 |page=2}}</ref> Instead, Apollo{{nbsp}}9 splashed down {{convert|160|nmi}} east of the Bahamas, about {{convert|3|mi}} from the recovery carrier, the [[USS Guadalcanal (LPH-7)|USS ''Guadalcanal'']],{{sfn|French & Burgess|p=353}} after a mission lasting 10 days, 1{{nbsp}}hour, 54 seconds.{{sfn|Mission Report|p=1-2}} Apollo{{nbsp}}9 was the last spacecraft to splash down in the Atlantic Ocean for a half century, until the [[Crew Dragon Demo-1]] mission in 2019,<ref>{{cite web|publisher=[[NASA]]|title=Crew Dragon splashes down in Atlantic ending first commercial crew mission|last=Moran|first=Norah|date=March 8, 2019|access-date=April 17, 2019|url=https://blogs.nasa.gov/spacestation/2019/03/08/crew-dragon-splashes-down-in-atlantic-ending-first-commercial-crew-mission/}}</ref><ref name=sleaf>{{cite news |url=https://news.google.com/newspapers?id=9WxYAAAAIBAJ&sjid=EvgDAAAAIBAJ&pg=7360%2C3565458 |work=Spokane Daily Chronicle |location=(Washington) |agency=Associated Press |title=Safe landing ends Apollo flight |date=March 13, 1969 |page=1}}</ref> and last crewed splashdown in the Atlantic until [[Inspiration4]] in 2021.<ref>{{cite news |title=SpaceX Inspiration4 crew returns to Earth in Atlantic Ocean splashdown |url=https://www.today.com/news/spacex-inspiration4-crew-makes-splashdown-atlantic-ocean-t231570 |access-date=September 18, 2021 |agency=Associated Press |date=September 18, 2021 |language=en}}</ref>