Editing AS-104

{{Short description|1965 orbital test of a Apollo spacecraft}}
{{use mdy dates|date=September 2021}}
{{Infobox spaceflight
| name                  = AS-104 
| image                 = Saturn SA8 launch.jpg
| image_caption         = Launch of Saturn AS-104
| insignia              =

| mission_type          = Spacecraft aerodynamics;<br>micrometeoroid investigation
| operator              = [[NASA]]
| COSPAR_ID             = 1965-039B
| SATCAT                = 1385
| mission_duration      = 8,810&nbsp;days<ref name="n2yo"/> <!-- calculated launch to decay date -->
| orbits_completed      = ~79,790
| distance_travelled    = {{convert|3282050195|km|mi|sp=us}}

| spacecraft            = [[Apollo (spacecraft)|Apollo]] BP-26<br>[[Pegasus 2]]
| manufacturer          = 
| launch_mass           = {{convert|1451.5|kg|lb}}
| landing_mass          =

| launch_date           = {{start date text|May 25, 1965, 07:35:01|timezone=yes}}&nbsp;UTC 
| launch_rocket         = [[Saturn I]] SA-8
| launch_site           = [[Cape Canaveral Air Force Station|Cape Kennedy]] [[Cape Canaveral Air Force Station Space Launch Complex 37|LC-37B]]
| decay_date            = {{end date text|July 8, 1989}}<ref name="n2yo">{{cite web|url=https://www.n2yo.com/satellite/?s=01385|title=Apollo Model 4|website=n2yo.com|access-date=February 3, 2023}}</ref>

| orbit_epoch           = 4 July 1965<ref name="satcat">{{cite web|url=http://planet4589.org/space/log/satcat.txt|title=Satellite Catalog|first=Jonathan|last=McDowell|work=Jonathan's Space Page|access-date=31 October 2013}}</ref>
| orbit_reference       = [[geocentric orbit|Geocentric]]
| orbit_regime          = [[Low Earth orbit]]
| orbit_periapsis       = {{convert|511|km|mi|sp=us}} 
| orbit_apoapsis        = {{convert|739|km|mi|sp=us}}
| orbit_inclination     = 31.7&nbsp;degrees
| orbit_period          = 97.2&nbsp;minutes 
| apsis                 = gee

| previous_mission      = [[AS-103]]
| next_mission          = [[AS-105]]
| programme             = [[Apollo program]]
}}
'''AS-104''' was the fourth orbital test of a [[Boilerplate (spaceflight)|boilerplate]] [[Apollo spacecraft]], and the second flight of the [[Pegasus (satellite)|Pegasus micrometeoroid detection satellite]]. It was launched by SA-8, the ninth [[Saturn I]] carrier rocket.

==Objectives==
The primary mission objective was to demonstrate the launch vehicle's iterative guidance mode and to evaluate system accuracy. The launch trajectory was similar to that of mission AS-103.

The Saturn launch vehicle SA-8 and payload were similar to those of mission AS-103, except that a single reaction control engine assembly was mounted on the boilerplate [[Apollo service module|service module]] (BP-26). The assembly was instrumented to acquire additional data on launch environment temperatures. This assembly also differed from the one on the AS-101 mission in that two of the four engines were of a prototype configuration instead of all engines being simulated.

==Launch==
This was the first nighttime launch in the Saturn I series. A built-in 35 minute hold was used to ensure that launch time coincided with the opening of the launch window.

AS-104 was launched from Cape Kennedy Launch Complex 37B at 2:35:01&nbsp;a.m. EST (07:35:01 GMT) on May 25, 1965.<ref>{{cite book|title=Saturn Illustrated Chronology - Part 6 January 1965 through December 1965|chapter=May 1965|url=https://history.nasa.gov/MHR-5/part-6.htm|publisher=NASA|access-date=February 3, 2023}}</ref> The launch was normal and the payload was inserted into orbit approximately 10.6 minutes after lift-off. The total mass placed in orbit, including the spacecraft, Pegasus B, adapter, instrument unit, and [[S-IV]] stage, was 34,113 pounds (15,473&nbsp;kg). The perigee and apogee were 314.0 and 464.1 miles (505 and 747&nbsp;km), respectively; the orbital inclination was 31.78'. The 1397&nbsp;kilogram (3080-pound) [[Pegasus 2]] satellite was also carried to orbit by SA-8, being stowed inside the boilerplate's service module, and remaining attached to the S-IV stage.

The actual trajectory was close to the one predicted, and the spacecraft was separated 806 seconds after lift-off. Several minor malfunctions occurred in the S-I stage propulsion system; however, all mission objectives were achieved.<ref>{{cite web|title=SA-8 operational trajectory|last1=Pack|first1=P. B.|last2=Solmon|first2=G.W. |url=https://ntrs.nasa.gov/citations/19650014195|date=May 17, 1965|access-date=February 3, 2023}}</ref><ref>{{cite web|title=SA-8 flight test data report|last=Weichel|first=H. J.|url=https://ntrs.nasa.gov/citations/19650021587|date=August 2, 1965 |publisher=NASA|access-date=February 3, 2023}}</ref>

{{commons category}}

==References==
{{reflist}}

==External links==
{{Portal|Spaceflight}}
*[https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1965-039A NSSDC: SA-8]
*[https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19650020205_1965020205.pdf Manned space flight network performance analysis for the SA-8 mission]

{{Apollo program| before=[[AS-103]] <br> [[A-003]]| after=[[AS-105]] <br> [[Pad Abort Test-2 (Apollo)|Pad Abort Test 2]]}}
{{Orbital launches in 1965}}

{{Include-NASA}}

{{Use American English|date=January 2014}}

[[Category:Apollo program]]
[[Category:Spacecraft launched in 1965]]
[[Category:1965 in the United States]]
[[Category:Test spaceflights]]
[[Category:Spacecraft launched by Saturn rockets]]
[[Category:Saturn I]]