View source for Engineering:Saturn I SA-2

{{Short description|Second flight of the Saturn I launch vehicle, April 25, 1962}}
{{Infobox spaceflight
| name                  = Saturn-Apollo 2
| image                 = Saturn SA2 on launch pad.jpg
| image_caption         = SA-2 sitting on Pad 34 with service structure
| mission_type          = Test flight
| operator              = [[Organization:NASA|NASA]]
| mission_duration      = 2&nbsp;minutes, 40&nbsp;seconds
| suborbital_apogee     = {{convert|105.3|km|mi|abbr=on}}
| distance_travelled    = {{convert|50|mi|km|disp=flip|abbr=on}}

| spacecraft            = 
| manufacturer          = 
| launch_mass           = {{convert|463|ST|kg|disp=flip|abbr=on}}

| launch_date           = {{start-date|April 25, 1962, 14:00:34|timezone=yes}}&nbsp;UTC
| launch_rocket         = [[Astronomy:Saturn I|Saturn I]] SA-2
| launch_site           = {{wipe|Cape Canaveral Air Force Station}} LC-34
| destroyed             = {{nowrap| {{end-date|April 25, 1962, 14:03:14|timezone=yes}}&nbsp;UTC }}<br/><small>([[Earth:Project Highwater|Project Highwater]])</small>

| previous_mission      = [[Engineering:Saturn I SA-1|Saturn I SA-1]]
| next_mission          = [[Engineering:Saturn I SA-3|Saturn I SA-3]]
| programme             = [[Astronomy:Apollo program|Project Apollo]]<br/><small>Uncrewed tests</small>
}}

'''Saturn-Apollo 2''' ('''SA-2''') was the second flight of the [[Astronomy:Saturn I|Saturn I]] launch vehicle, the first flight of [[Earth:Project Highwater|Project Highwater]], and was part of the American [[Astronomy:Apollo program|Apollo program]]. The rocket was launched on April 25, 1962, from {{wipe|Cape Canaveral Air Force Station}}, Florida.

== History ==

Launch preparation for the mission began at Cape Canaveral on February 27, 1962, with the arrival of the second Saturn I launch vehicle. The only significant change made to the vehicle from the previous [[Engineering:Saturn I SA-1|SA-1]] flight was the addition of extra baffles in the propellant tanks to mitigate fuel [[Physics:Slosh dynamics|sloshing]]. While no serious delays were encountered, there were several minor problems reported.<ref name="Benson1978" />

A leak was detected between the liquid oxygen dome and injector for the #4 H-1 rocket engine; while attempts were made to fix the problem, it was eventually decided to launch without replacing the engine. Minor problems were found in the guidance subsystem and service structure operations, damaged [[Physics:Strain gauge|strain gauge]]s were found in a liquid oxygen stud and truss member, and a manhole cover on the dummy [[Engineering:Centaur (rocket stage)|Centaur]] (S-V-D) third stage had to be replaced. Problems arose with two of the fueling computers, but each was repaired. Three hydraulic systems were also listed as potential problems.<ref name="Benson1978" />

Despite the issues encountered during flight preparation, none required the target launch date of April 25 to be pushed back.<ref name="Benson1978" />

== Flight ==
[[File:Saturn SA2 launch.jpg|thumb|left|upright|Launch of SA-2]]

Saturn-Apollo 2 was launched at 14:00:34 UTC on April 25, 1962, from Launch Complex 34.<ref name="Ryba2009" /> The only hold in the countdown sequence was for 30 minutes due to a vessel which entered the flight safety zone {{convert|96|km|mi|disp=flip|sp=us}} down range.<ref name="Benson1978" /><ref name="Brooks1979" /> The rocket carried {{convert|281000|kg|lb|disp=flip}} of propellant, about 83% of its maximum capacity.<ref name="Benson1978" />

The H-1 engines shut down at an altitude of {{convert|35|mi}} after firing for 1 minute 55 seconds and reaching a maximum velocity of {{convert|3750|mph}}.<ref name="nashua19620425" /><ref name="Ertel1969" /> The vehicle continued to coast to an altitude of {{convert|105.3|km|mi|disp=flip|sp=us}},<ref name="Woodbridge1965" /> at which point, 2 minutes 40 seconds after launch,<ref name="nashua19620425" /> officials sent a terminate command to the rocket, setting off several charges which caused the vehicle to destruct.<ref name="Benson1978" />

== Objectives ==

The objectives of SA-2 were much the same as those of [[Engineering:Saturn I SA-1|SA-1]] in that it was primarily a test of the Saturn I rocket and the new H-1 engines. Specifically, its goals were to prove propulsion performance and mission adequacy, vehicle structural design and aerodynamic characteristics, guidance and control systems, and launch facility and ground support equipment. NASA declared all objectives as successful. Additionally, the fuel sloshing issue from SA-1 was minimized.<ref name="Brooks1979" />

A second objective of both this mission and [[Engineering:Saturn I SA-3|SA-3]] was Project Highwater, the intentional release of ballast water from the second and third stages which allowed scientists to investigate the nature of Earth's [[Astronomy:Ionosphere|ionosphere]], as well as [[Earth:Noctilucent cloud|noctilucent cloud]]s and the behavior of ice in space.<ref name="Woodbridge1965" />

SA-2's dummy upper stages contained approximately {{convert|86000|kg|disp=flip}} of water,<ref name="Woodbridge1965" /> or {{convert|86685|L|USgal|disp=flip|sp=us}},<ref name="Brooks1979" /> used to simulate the mass of future payloads. Stage two contained {{convert|44000|kg|disp=flip}} of water, and stage three contained {{convert|42000|kg|disp=flip}}.<ref name="Woodbridge1965" /> When the terminate command was sent to the rocket, dynamite charges<ref name="nashua19620425" /> split the second stage longitudinally, instantly releasing its water load.<ref name="Woodbridge1965" /> Primacord charges created several {{convert|1|ft|adj=on}} holes in the third stage, releasing its water over a period of several seconds.<ref name="Woodbridge1965" />

Cameras on the ground immediately recorded the water cloud, and personnel at a ground station began to observe it about four to five seconds after release.<ref name="Ryba2009" /><ref name="Woodbridge1965" /> Those personnel reported that the cloud dispersed from vision within an average of five seconds,<ref name="Woodbridge1965" /> while more sensitive instruments tracked the cloud to a maximum altitude of {{convert|161|km|mi|disp=flip|sp=us}}.<ref name="Benson1978" /> The cloud produced lightning-like effects, which Dr. [[Biography:Wernher von Braun|Wernher von Braun]] described as "probably the first synthetic thunderstorm ever generated in space."<ref name="ap19620426" /> Project Highwater on this flight was also declared a success.<ref name="Ertel1969" />

== References ==
{{Include-NASA}}
{{reflist |refs=
<ref name="nashua19620425">{{cite news |url=https://news.google.com/newspapers?id=prorAAAAIBAJ&pg=3273%2C4883729 |title=Big US Rocket Releases 95 Tons of Water in Sky |work=Nashua Telegraph |location=Nashua, NH |agency=Associated Press |volume=93 |issue=47 |pages=1, 3 |date=April 25, 1962}}</ref>

<ref name="ap19620426">{{cite news |title=Saturn Brews Space Thunderstorm |url=https://www.newspapers.com/clip/120552783/saturn-brews-space-thunderstorm/ |access-date=March 10, 2023 |work=San Angelo Standard-Times |agency=Associated Press |issue=86 |date=April 26, 1962 |archive-url=https://web.archive.org/web/20230310112329/https://www.newspapers.com/clip/120552783/saturn-brews-space-thunderstorm/ |archive-date=March 10, 2023 |page=28 |url-status=live |via=Newspapers.com }}</ref>

<ref name="Benson1978">{{cite book |url=https://ntrs.nasa.gov/search.jsp?R=19790003956 |title=Moonport: A History of Apollo Launch Facilities and Operations |chapter-url=http://www.hq.nasa.gov/office/pao/History/SP-4204/ch10-1.html |chapter=Saturn I Launches (1962 - 1965) |publisher=NASA |first1=Charles D |last1=Benson |first2=William Barnaby |last2=Faherty |year=1978 |id=Special Publication 4204; Accession number N79-12127}}</ref>

<ref name="Ryba2009">{{cite web |url=https://www.nasa.gov/mission_pages/apollo/missions/Saturn_Test_Flights.html |title=Saturn Test Flights |work=NASA.gov |first=Jeanne |last=Ryba |date=July 8, 2009 |access-date=May 3, 2012 |archive-url=https://web.archive.org/web/20221210091211/https://www.nasa.gov/mission_pages/apollo/missions/Saturn_Test_Flights.html |archive-date=December 10, 2022 |url-status=live }}</ref>

<ref name="Woodbridge1965">{{cite book |url=https://ntrs.nasa.gov/search.jsp?R=19650011729 |title=An Analysis of Project High Water Data |publisher=NASA |first1=David D |last1=Woodbridge |first2=James A |last2=Lasater |date=March 6, 1965 |id=Accession number N65-21330}}</ref>

<ref name="Brooks1979">{{cite book |url=https://ntrs.nasa.gov/search.jsp?R=19790020032 |title=Chariots for Apollo: A History of Manned Lunar Spacecraft |publisher=NASA |first1=Courtney G |last1=Brooks |first2=James M |last2=Grimwood |first3=Loyd S |last3=Swenson, Jr |year=1979 |pages=381–2 |id=Special Publication 4205; Accession number N79-28203}}</ref>

<ref name="Ertel1969">{{cite book |url=https://ntrs.nasa.gov/search.jsp?R=19690022643 |title=The Apollo Spacecraft: A Chronology - Volume 1 |publisher=NASA |first1=Ivan D |last1=Ertel |first2=Mary Louise |last2=Morse |year=1969 |page=155 |id=Special Publication 4009; Accession number N69-32021}}</ref>

}}

== External links ==

{{Apollo program |before=[[Engineering:Saturn I SA-1|SA-1]] |after=[[Engineering:Saturn I SA-3|SA-3]]}}


[[Category:Apollo program]]
[[Category:Test spaceflights]]
[[Category:Spacecraft launched by Saturn rockets]]

{{Sourceattribution|Saturn I SA-2}}