Editing Sputnik 2 (section)

===Experiments===

[[File:Atmospheric_electromagnetic_opacity.svg|thumb|300px|Wavelengths of light blocked by Earth's atmosphere.]]

Sputnik 2 was the first platform capable of making scientific measurements in orbit. This was potentially as significant as the biological payload. The [[Atmosphere of Earth|Earth's atmosphere]] blocks the Sun's X-ray and ultraviolet output from ground observation. Moreover, solar output is unpredictable and fluctuates rapidly, making sub-orbital [[sounding rocket]]s inadequate for the observation task. Thus a satellite is required for long-term, continuous study of the complete solar spectrum.<ref name="SP100">{{cite book |date=1966 |title=Significant Achievements in Solar Physics 1958–1964|publisher=NASA|oclc=860060668}} {{PD-notice}}</ref>{{Rp|5–6, 63–65}}<ref name=NAP>{{cite book|chapter-url=https://www.nap.edu/read/11299/chapter/8#157 |author=Committee on the Navy's Needs in Space for Providing Future Capabilities, Naval Studies Board, Division on Engineering and Physical Sciences, National Research Council of the National Academies|title=The Navy's Needs in Space for Providing Future Capabilities |chapter=Appendix A: Department of the Navy History in Space|page=157|date=2005|access-date=January 6, 2019|publisher=The National Academies Press|archive-url=https://web.archive.org/web/20190107015833/https://www.nap.edu/read/11299/chapter/8#157|archive-date=January 7, 2019|url-status=live|isbn=978-0-309-18120-4|doi=10.17226/11299}} {{PD-notice}}</ref>

Accordingly, Sputnik 2 carried two spectrophotometers, one for measuring solar ultraviolet rays and one for measuring X-rays. These instruments were provided by Professor Sergei Mandelstam of the Lebedev Institute of Physics and installed in the nose cone above the spherical PS. In addition, Sergei Vernov, who had completed a cosmic ray detector (using [[Geiger counter]]s) for Object D, demanded that the instrument his Moscow University team (including Naum Grigoriev, Alexander Chudakov, and Yuri Logachev) had built also be carried on the flight. Korolev agreed, but as there was no more room on the satellite proper, the instrument was mounted on the Blok A and given its own battery and telemetry frequency.<ref name=rsp/>{{rp|30,32}}

Engineering and biological data were transmitted using the Tral_D telemetry system, which would transmit data to Earth for 15 minutes of each orbit.<ref name=nssdcsput2/>