Problem Solving: LightSail 2
LightSail 2 was a satellite that was designed to use solar
radiation to change its altitude as it circled Earth. The
spacecraft had a mass of 5.0kg. It was originally launched by a
rocket with its sail closed, and established an orbit at an
altitude of 720 km above Earth’s surface. Then it deployed its
sail, which had an area of 32m2. Assume the sail is completely
reflective.
1) After a full month of “½ time exposure” (you don’t want the sail
turned towards the sun during the part of the orbit in which the
change in momentum would slow the craft), what would be the
expected change in the craft’s speed? Assume a 30 day month. Also
assume all the force goes into a change in speed. 2) What would be
its change in orbital altitude (assuming circular orbits)?
Hints:
o You will need to look up a number of constants about the Sun and
Earth. o One thing a sophisticated solution should consider is that
the gravitational force from Earth at the satellite’s location is
NOT “mg” with “g” as 9.8m/s2. If you go to this level of
sophistication then you will need to use the equation for
gravitational force between two spherical masses, i.e. the one with
“G,” the universal gravitational constant. Also, if you go to this
level of sophistication, your result will probably surprise you. It
may be useful to then look at a chart of planetary speeds versus
planetary orbits. And discuss. Also note: this would really cause
the spacecraft to develop orbits with eccentricity (elliptical
characteristics). It had limited success. A lot of “tumbling”
occurred but some altitude deviations were observed with enough
consistency to be presented in publication.
Problem Solving: LightSail 2 LightSail 2 was a satellite that was designed to use solar radiation...
Problem Solving: LightSail 2 BOOM LENGTH TOTAL SAIL AREA SIZE REFERENCE 5.6 x 5.6 m (18.4x 18.4ft) 4 m (13ft) 32 m (344ft) Boxing Ring SAIL DEPLOYMENT PROPULSION LightSail 2 was a satellite that was designed to use solar radiation to change its altitude as it circled Earth. The spacecraft had a mass of 5.0kg. It was originally launched by a rocket with its sail closed, and established an orbit at an altitude of 720 km above Earth's surface. Then...
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