11. Solar Sail Celestial Travel: NASA has just discovered, to their delight, that the NIU Physics 211 students understand the principles of solar sail travel. You have been contracted to solve their problem of sending two sailors to Mars (a) NASA has been able to design extremely lightweight solar sails having a density of 3x10 gram/m. If each of the 4 solar sails has an area of 2 km and a thickness of 3 microns, what is the total combined mass of the 4 solar sails? (b) NASA has measured that 1400 Joules of sunlight are incident upon each square meter of the solar sails each second. If the average wavelength of sunlight is 0.55 microns, how many photons are incident upon the 4 solar sails? (c) What is the momentum of a single photon having a wavelength of 0.55 microns? (Read Section 27.5 in Giambattista). (d) Apply momentum conservation to show that the momentum transferred to the sail is twice the momentum of the incident photon (the photon is completely reflected from the metallic solar sail): P-20 (e) Assume that the total weight of the solar sail craft (including sails, people, living quarters, etc.) is 100,000 kg. Using the relationship in Part (d), what is the velocity of the craft if it is pushed by all the photons calculated in Part (b)? (1) If the distance from Earth to Mars is 78x10 km, how long (in days) will it take for the craft to reach Mars? Sun Sails Living quarters 11. Solar Sail Celestial Travel: NASA has just discovered, to their delight, that the NIU Physics 211 students understand the principles of solar sail travel. You have been contracted to solve their problem of sending two sailors to Mars.