Figure 3.3a. Historical Astronomy

Updates Seminar dates (5 total) for Extra credit are now posted on the website: 1/26: Zahnle Sections will start next week Homework is Due next Thursday Reid s OH change: T: 2-3 & W: 1-2

Figure 3.3a Historical Astronomy

Figure 3.3b

Outline Ptolemy s model of the universe Before Copernicus there was Aristarchus Kepler s 3 laws Newton s 3 laws What can we learn from these laws? The beginning of the space age... Apollo

Figure 3.14 Ptolemy s geocentric model of the Universe Click for Astrology

Show SkyGazer Mars

Figure 3.15 Annotated

Figure 2.33b Unannotated

Drawing by Carter Emmart, in David Grinspoon s Venus Revealed

Unnumbered Figure 3.2

Unnumbered Figure 3.2 Aristarchus (310-230 BC)

Moon orbits every 29.5 days

d 87 o Aristarchus (310-230 BC)

20 x d d 87 o Aristarchus (310-230 BC)

Actually... 400 x d d 0.5 o Aristarchus (310-230 BC)

Unnumbered Figure 3.1 Annotated

Unnumbered Figure 3.3

At this point we need to introduce some planetary orbital mechanics Kepler s Three Laws of Motion: Law of Orbits, Law of Areas, Law of Periods 1. Kepler s Law of Orbits: Planets orbit the sun in ellipses

Figure 3.18

Figure 3.19 Unannotated

Kepler s 2nd Law Planets orbit faster closer to the sun and slower farther from the sun

Figure 4.14a Annotated

3. Kepler s Law of Periods: P 2 a 3 For planets orbiting the Sun if a is in AU and P in years: P 2 yrs= a 3 AU Earth: 1 AU, 1 year Jupiter: 5.2 AU, 11.9 years Neptune: 30 AU, what is P?

3. Kepler s Law of Periods: P 2 a 3 For planets orbiting the Sun if a is in AU and P in years: P 2 yrs= a 3 AU Earth: 1 AU, 1 year Jupiter: 5.2 AU, 11.9 years Neptune: 30 AU, what is P? P yr = 30 3 = 9000 =164yr

Figure 3.21 Annotated

Unnumbered Figure 4.1

Unnumbered Figure 4.1 1) A body in motion will stay in motion, and a body at rest will stay at rest until acted upon by a force.

Unnumbered Figure 4.1 1) A body in motion will stay in motion, and a body at rest will stay at rest until acted upon by a force. 2) Force = mass x accel.

Unnumbered Figure 4.1 1) A body in motion will stay in motion, and a body at rest will stay at rest until acted upon by a force. 2) Force = mass x accel. 3) For every applied force there is an equal and opposite force.

Figure 3.21 Annotated Newton used his equation to figure out the speed of the planets

Newton Revised Kepler s 1st Law to describe the mutual motion of two objects as they orbit each other.

Newton re-wrote Kepler s 2nd law to describe the exchange between kinetic and potential energy as planet traversed its ellipse

Figure 4.22 Annotated

Figure 4.3 Unannotated

Figure 4.3 Annotated

Unnumbered Figure 3.7

Figure 3.24

SkyGazer planet orbits.

Recap Kepler s Laws: 1) Planets orbit follows an ellipse 2) Equal areas of the ellipse is swept out in equal times 3) p 2 = a 3 Newton s Laws: 1) Object in motion will stay in motion, and an object at rest will stay at rest until acted upon by a force 2) F = ma 3) For every force there is an equal and opposite force

Recap Weightlessness in space is caused by the free falling spacecraft around Earth, not by a lack of gravity Planets close to the sun travel faster than objects further away (Kepler s third law). The exchange of an object s gravitational potential energy with kinetic energy results in Kepler s second law. However total energy remains constant

Messenger Trajectory

Messenger Trajectory Which side of a planet do you want to flyby if you want your spacecraft to speed up?

Figure 4.21

On to the History of Spaceflight...

Why Do We Need Rockets? Modes of transportation on Earth won t work in space Wheels: no surfaces Propellers: no atmosphere or liquid Wings: no atmosphere Jet engines: no atmosphere Rockets that carry their own fuel on board and burn the fuel to move are required Rockets use the principle of Newton s 3rd Law (law of reciprocal actions)

Early Spaceflight In the 1940s, Rolls Royce engineers concluded that spaceflight was impossible. Rocket Equation (Konstantin Tsiolkovsky, 1903) based on Newton s 3 rd law of equal action-reaction: m final = m initial e Δv / v exhaust

Wernher von Braun (1912-1977) German rocket scientist Helped develop the V2 ballistic missile for Nazis At end of WWII, race between Soviets and US to recruit German rocket scientists US Army had special units to find and recruit von Braun surrendered to US and transferred to Fort Bliss, TX to work on US ballistic missiles Became director of NASA s Marshall Spaceflight Center in Huntsville, AL Chief architect behind the Saturn V booster rockets

V2 Rocket Single stage rocket - used alcohol and liquid oxygen as propellant Successfully tested first 1942 by Germany: flew 120 miles Hitler assigned high priority to V2 By end of WWII, Germany had launched 3,000 V2s at England, France and Belgium First US V2 (built under direction of von Braun) launched 1946 in NM Rockets then launched upwards Achieved 65 miles altitude in late 1946 - camera attached

Picture of V2

V2 Panorama V-2 launched on March 7, 1947, took this picture from 101 miles up. The dark area is the Gulf of California.

The Space Race Begins USSR also had V2 technology Called theirs the R1 missile First launched successfully in 1948 Fifth generation missile R5 achieved ballistic range of 750 miles

WAC Corporal US rocket project during WWII; similar size to V2 Designed and built at Jet Propulsion Lab, Pasadena Used solid propellant rockets to get off the launch pad, then liquid propellant to go skyward.

Bumper WAC Rocket The first to space Result of pairing WAC Corporal and V2 World s first 2-stage liquid-propellant rocket Set altitude record in 1949 to 250 miles Record launch was from what is know Kennedy Space Center, Cape Canaveral, FL

Multi-Stage Rockets Rolls Royce engineers concluded in 1940s that spaceflight was impossible Their calculations were based on single-stage rockets Single-stage rockets must carry entire payload, plus fuel and fuel tank into orbit Currently no single-stage-to-orbit launch vehicles have ever been constructed from Earth that is! Lunar module was launched from the Moon with a single stage rocket. Multi-stage rockets can drop empty fuel tanks on the way up, lessening the weight

Intercontinental Ballistic Missiles Focus shifted back to ballistic missiles after nuclear technology progressed By 1953, US had developed lightweight hydrogen bomb Testing began in 1954 USSR had ICBM (R7) capable of hitting US by 1957

Sputnik The October Surprise October 4, 1957 USSR used an ICBM to put a satellite (Sputnik I) into orbit Sputnik transmitted radio signals that could be heard all over the world US was working on own satellite but was much smaller than Sputnik - US caught off-guard Big impetus for US space program and science in general Some say this is the real beginning of the Space Race

Picture of Sputnik Sputnik was a bit bigger than a basketball and weighed 183 pounds

The Second Blow Sputnik II launched just a month after Sputnik I and was much larger! Sputnik II carried the first space passenger: Laika the dog Between 1958 and 1961, 6 more Sputniks were launched, each larger than the last

The US Replies In January 1958, the US launched Explorer I on a modified Jupiter-C rocket (then called Juno I) Juno I was a 3-stage rocket developed by von Braun and team Explorer I was developed at JPL Explorer I had scientific payload that studied Earth s radiation belt (Van Allen Belt)

NASA Up until 1958, Department of Defense had been managing rocketry, under the auspices of the National Advisory Committee on Aeronautics (NACA). After Sputnik, pressure mounted to show that we were not at a technological disadvantage with USSR Congress passed the National Aeronautics and Space Act in July 1958, which founded the National Aeronautics and Space Administration.

Luna In 1959 the USSR launched Luna 3, which orbited the moon and took the first pictures of the far side of the moon

Yuri Gagarin April 12, 1961, Soviet cosmonaut Yuri Gagarin became first human in space Circled the earth once and returned safely Occurred 1 month before Shepard s suborbital flight and 10 months before Glenn s orbital flight This flight sent message to the US: USSR is way ahead in the Space Race Check out Yuri s Night, the Cinco de Mayo of space.

Mercury Program "I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the Moon and returning him safely to the Earth. President John F. Kennedy, 1961. 1958-1963, US s first manned spaceflight program Goals: to orbit a manned spacecraft around Earth, to investigate man s ability to function in space, and to recover both man and spacecraft safely 20 unmanned flights between 1959 and 1961 7 astronauts chosen 6 manned flights between 1961 and 1963

Animal Astronauts NASA began sending monkeys into space in 1959 4 of Mercury launches were manned by monkeys

Mercury Astronauts 1961: Alan Shepard became first American to make suborbital space flight 1962: John Glenn became first American to orbit Earth 1963: Gordon Cooper became first American to spend an entire day in space

More Soviet Firsts 1962: First two-spacecraft mission 1963: First multi-day mission (5 days in orbit) 1963: Valentina Tereshkova became first woman in space

Spacewalking 1965: Aleksei Leonov became first human to go outside spacecraft Spent 20 minutes spacewalking Suit overinflated and had to vent it to get back inside spacecraft Later the same year, Edward White became first American to spacewalk

Gemini Program 1964-1966 One goal was to have 2-man long-duration flights 2 unmanned flights 10 manned missions Improved spacecraft control techniques Rendezvous and docking First US spacewalk 1965: astronauts Borman and Lovell spent record-breaking 14 days in space

Soviet Lunar Program Zond circumlunar missions 1965-1970 1968: Zond 5 became first probe to loop around moon and return to Earth Soyuz and Kosmos missions tested lunar spacecraft and maneuvers 1966-1969 L3 man-on-the-moon mission scheduled for 1968 but never executed Lunokhod missions landed rovers on the moon: took pictures and analyzed rock and soil 1970-1973 BUT USSR didn t have a powerful enough launch vehicle for manned mission to moon

Saturn V Rocket Developed at NASA s Marshall Spaceflight Center under direction of Wernher von Braun 3-stage rocket Taller than a 36-story building Biggest, most powerful rocket ever launched 15 Saturn Vs were built Never failed

US Lunar Reconnaissance 1961-1965: Ranger missions to first close-up pictures of moon 1966-1968: Surveyor missions landed on the moon and conducted soil tests 1966-1967: Lunar Orbiter missions mapped possible landing sites

Apollo Program 1968-1972 6 unmanned missions 12 manned missions Apollo 8: first manned lunar orbital mission; took first pictures of Earthrise Apollo 9: first manned flight of lunar module Apollo 10: dress rehearsal for lunar landing; partial descent to moon

Tragedy on the Launchpad January 1967: Apollo 1 burns on the launchpad, killed 3 astronauts Manned flights halted for almost 2 years while Apollo capsules were redesigned April 1967: Soviet Soyuz 1 had parachute failure, crash landed and killed 1 cosmonaut USSR halted manned flight for 18 months

Soviet Lunar Sample Return? Soviets realized they couldn t beat US to land man on the moon Instead sent robotic mission to collect and return moon rocks and soil to Earth ahead of astronauts return Luna 15 spacecraft crash landed on the moon

The Moon Landing July 20, 1969 Apollo 11: Neil Armstrong, Buzz Aldrin, Michael Collins

Other Apollo Missions 1969, Apollo 12: landed on moon, retrieved parts of Surveyor 3 which landed on moon in 1967 1970, Apollo 13: supposed to land on the moon but had oxygen tank leak - had to circle around moon and fly straight home 1971, Apollo 14: Deployed science instruments, gathered rocks 1971, Apollo 15: First of the longduration stays on lunar surface, drove Lunar Roving Vehicle on the moon 1972, Apollo 16: First study of lunar highlands, used UV camera on surface 1972, Apollo 17: First scientistastronaut landed on moon

Moon Hoax? 800 kg of rocks returned from the Apollo missions Spherical glass beads Radiometric age dates ~ 3.8 Ga Cosmic ray-generated isotopes Micro-meteorite impacts Laser reflectometer used to measure the moon s distance