Editing Mariner 5 (section)

==Experiments==
Mariner 5 returned data from seven experiments:<ref>{{Cite web |title=Mariner 5 Experiment Search Results |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/displayExperiment.action?spacecraftId=1967-060A |website=NSSDCA Master Catalog}}</ref>

=== Celestial Mechanics ===
Tracking data from Mariner 5, combined with [[NASA Deep Space Network|Deep Space Network]] equipment, were used to refine the masses of Venus and the Moon, improve the [[astronomical unit]], and update Earth-Venus [[Ephemeris|ephemerides]]. [[Doppler effect|Doppler]] measurements worked effectively up to 48 million km. Principal investigator was [[John D. Anderson]] from the [[Jet Propulsion Laboratory]].<ref>{{Cite web |title=Celestial Mechanics |url=https://nssdc.gsfc.nasa.gov/nmc/experiment/display.action?id=1967-060A-07 |website=NSSDCA Master Catalog}}</ref>

=== Interplanetary Ion Plasma Probe for E/Q of 40 to 9400 Volts ===
This three-part [[Faraday cup]] measured positive ions from 40 to 9400 eV/Q in eight energy ranges. Always facing the Sun, it gathered directional data by comparing signals from its three 120° collectors. It cycled through voltage settings in two modes—total and individual plate currents—producing 64 measurements every 5 minutes. The instrument functioned normally throughout the mission. Principal investigator was Herbert S. Bridge from the [[Massachusetts Institute of Technology]].<ref>{{Cite web |title=Interplanetary Ion Plasma Probe for E/Q of 40 to 9400 Volts |url=https://nssdc.gsfc.nasa.gov/nmc/experiment/display.action?id=1967-060A-03 |website=NSSDCA Master Catalog}}</ref>

=== S-Band Occultation ===
This experiment aimed to study Venus's atmosphere and [[ionosphere]] by analyzing changes in the [[S band|S-band]] signal, including phase shift, Doppler shift, and signal weakening. Principal investigator was Arvydas J. Kliore from the Jet Propulsion Laboratory.<ref>{{Cite web |title=S-Band Occultation |url=https://nssdc.gsfc.nasa.gov/nmc/experiment/display.action?id=1967-060A-01 |website=NSSDCA Master Catalog}}</ref>

=== Trapped Radiation Detector ===
This experiment aimed to measure energetic particles in interplanetary space and investigate potential radiation belts or particle effects near Venus. It used specialized detectors to capture electrons and protons at various [[Energy level|energy levels]] and angles relative to the probe-Sun line. Principal investigator was [[James Van Allen|James A. Van Allen]] from the [[University of Iowa]].<ref>{{Cite web |title=Trapped Radiation Detector |url=https://nssdc.gsfc.nasa.gov/nmc/experiment/display.action?id=1967-060A-04 |website=NSSDCA Master Catalog}}</ref>

=== Triaxial Low Field Helium Magnetometer ===
This experiment used a helium [[magnetometer]] mounted on a 1.5-meter boom to measure interplanetary and Venusian magnetic fields in three directions. It operated in both high and low bit-rate modes, collecting precise data with a dynamic range of ±204 nT and accuracy up to ±0.2 nT. High-quality data were gathered from June to October 1967, except for a brief period in late September. Principal investigator was Edward J. Smith from the Jet Propulsion Laboratory.<ref>{{Cite web |title=Triaxial Low Field Helium Magnetometer |url=https://nssdc.gsfc.nasa.gov/nmc/experiment/display.action?id=1967-060A-05 |website=NSSDCA Master Catalog}}</ref>

=== Two-Frequency Beacon Receiver ===
A steerable antenna at Stanford transmitted two radio signals (423.3 MHz and 49.8 MHz) to the spacecraft’s two-frequency receiver. The high-frequency signal acted as a reference, while delays in the low-frequency signal revealed total electron content along the path. Phase and group velocity differences were measured onboard and sent back to Earth, helping to determine interplanetary electron content and [[solar wind]] variations. The experiment ran successfully from launch through November 1967. Principal investigator was Von R. Eshleman from [[Stanford University]].<ref>{{Cite web |title=Two-Frequency Beacon Receiver |url=https://nssdc.gsfc.nasa.gov/nmc/experiment/display.action?id=1967-060A-02 |website=NSSDCA Master Catalog}}</ref>

=== Ultraviolet Photometer ===
This experiment used a [[Ultraviolet|UV]] [[photometer]] to study Venus' upper atmosphere by measuring ultraviolet emissions caused by solar radiation scattering off atmospheric atoms. By analyzing these emissions, especially hydrogen [[Lyman-alpha]] and [[atomic oxygen]] lines, scientists could determine the composition and temperature at various altitudes. The instrument had three [[Photomultiplier tube|photomultiplier tubes]] with specific filters to isolate key wavelengths. Principal investigator was Charles A. Barth from the [[University of Colorado]].<ref>{{Cite web |title=Ultraviolet Photometer |url=https://nssdc.gsfc.nasa.gov/nmc/experiment/display.action?id=1967-060A-06 |website=NSSDCA Master Catalog}}</ref>