Starshine 2

Launch data: Designation  26996 / 01054B Launch date  05 Dec 2001 - 22:19:28 UT Launch site  KSC, LC39B Launch vehicle  Shuttle STS-108 Mission   Earth orbit on: Perigee / Apogee   km Eccentricity   Inclination   deg Period   min

Photo of Starshine-2 (image credit: NRL, Project Starshine)

Description:

• STARSHINE is a US cooperative program of small optically reflective spherical student satellites, designed and built by NRL/NCST (Naval Research Laboratory/Naval Center for Space Technology). They are being deployed by NASA from Hitchhiker canisters in Space Shuttle cargo bays, as well as from an Athena unmanned launch vehicle, into highly inclined low earth orbits at a rate of once every year or so.
• Each of the satellites is covered by approximately 850 small, front-surface aluminum mirrors (2.54 cm diameter) that are machined by technology students in Utah and polished by tens of thousands of students in schools and other participating organizations around the world. These mirrors have been coated with a scratch-resistant, anti-oxidizing layer of Silicon Dioxide by optical engineers and technicians at the Hill Air Force Base in Utah and the NASA Marshall Space Flight Center in Alabama.
• During the satellite′s orbital lifetime, faint sunlight flashes from its mirrors were naked-eye visible against the star background, during certain recurring morning and evening twilight periods, to student and adult observers around the world between the latitudes of 60 degrees north and 60 degrees south.
• These observers measured the satellite′s right ascension and declination by reference to known stars, and they recorded the precise timing of their observations by the use of stopwatches synchronized with international time signals. They used GPS receivers or United States Geological Survey 7 ½ minute quadrangle maps, or their equivalents in other countries, to measure the latitude, longitude and altitude of their observing sites. They posted their observations and station locations on the Starshine web site to permit computation of the classical elements of the satellite′s orbit by the angles only method of LaPlace.
• From day to day, the period of the satellite′s orbit grew shorter, due to the afore-mentioned aerodynamic drag. Students measured the magnitude of the daily decrease of period and deduced the density of the earth′s upper atmosphere that produced the drag that shortened the satellite′s orbital period. They also kept track of fluctuations in intensity of extreme ultraviolet radiation from the sun, as measured by instruments on the SOHO satellite. They related fluctuations in intensity of solar activity to changes in the rate of decay of the satellite′s orbit and thereby to variations in atmospheric density.

Mission details:

• The second satellite, Starshine 2, was deployed from Space Shuttle Endeavor on December 16, 2001, near the end of Endeavor′s STS-108 mission to the International Space Station.
• The Starshine-2 reflector satellite was ejected from the MACH-1 bridge in Endeavour&priùe;s payload bay at 1502 UTC on Dec 16, 2001. It is part of an educational project and will be tracked by school students around the world.
• The satellite′s initial altitude was 370 kilometers, and its orbital inclination to the earth′s equator was 51.6 degrees. The 858 mirrors that covered the outside surface of this satellite were polished by approximately 30,000 students in nearly 700 schools in 26 countries. Engineers at the U.S. Naval Research Laboratory installed the mirrors on the Starshine 2 satellite shell and performed final acceptance vibration testing of the completed satellite, prior to its installation in a Hitchhiker canister at the NASA Goddard Space Flight Center. The satellite is the same size and mass as the Starshine 1 satellite, but it also contains a special cold gas spin system that rotated the satellite at 5 degrees per second as it was deployed from the Space Shuttle. This motion was designed to increase the number of flashes of sunlight that can be seen as the satellite travels across the sky. In addition, Starshine 2 carries thirty one laser retro-reflectors, distributed evenly across its surface, to permit the International Satellite Laser Ranging Network to track it.
• Starshine 2 descended into the lower atmosphere and flamed out on 26 April 2002. The fact that its orbital lifetime was so much shorter than that of Starshine 1 was due to its slightly lower deployment altitude, coupled with unusually high solar activity.

Photo of Starshine-2 as it was deployed from the payload bay of Endeavour during STS-108 (image credit: NASA)

Starshine 2′s orbital decay curve (image credit: NASA)

External links:

• EOportal.org Satellite description