October 16, 2017 - Orbiting Yardstick Gets a Lift

Orbiting Yardstick Gets a Lift Thundering aloft through the Florida sky twenty-five years ago this week, the space shuttle Columbia sets off on the STS-52 mission. The main objective of the flight was deploying the second Laser Geodynamic Satellite (LAGEOS II), a joint project between NASA and the Italian Space Agency. The spherical LAGEOS II is covered with over 400 retroreflectors, or prisms, that can reflect a laser beam from Earth directly back at its source. Laser ranging stations on Earth measure the round-trip time of the laser beam and calculate their locations with great accuracy and can thus determine very small fluctuations in the movement of Earth’s crust or any “wobble” in Earth’s rotation. LAGEOS II will orbit Earth indefinitely at an altitude of 5,900 km (3,700 mi).

Image credit: NASA

Weekly Calendar

October 16-22, 2017

Holidays - Sky Events - Space History

Monday 16

Tuesday 17

Mars 1.8° south of Moon
Venus 2° south of Moon

1956: Mae Jemison born
2016: Shenzhou-11 launched

Wednesday 18

1967: Venera 4 makes first direct studies of Venus’s atmosphere
1989: STS-34 Atlantis launched
1993: STS-58 Columbia launched
2003: ISS Expedition 8 crew launched