Space and Space Exploration

Why Space Exploration Is Dangerous

1.) near-vacuum and extreme cold 2.) lack of “down” direction 3.) high radiation exposure 4.) space vehicles are fragile/complex to get heavy objects into space 5.) difficult to fix things that go wrong and try to hit very distant targets

Orbit

regular, repeating path that one object in space takes around another one

Satellite

an object in orbit; can be natural (moon, earth) or man-made (ISS, Hubble Telescope)

Newton’s 1st Law of Motion (Inertia)

an object at rest will stay at rest forever, until a force acts on it; an object in motion will stay in motion forever, until something pushes or pulls on it

Gravity

attraction between two objects with mass

Orbits A & B

unable to overcome the force of gravity, at lower velocities the rocket will travel a distance over earth before falling to ground

Orbits C & D

rocket reaching the orbital velocity will enter into orbit around earth (C), higher speeds will lead to D

Orbit E

escape velocity must be reached, 7 mi/sec or 25,000 mph

Low-Earth Orbit (LEO)

easiest to get/stay in, altitude=~1,240 mi, one orbit complete in ~90 mins, polar orbits

Geosynchronous Earth Orbit (GEO)

satellites follow rotation of the earth (geostationary), ~23,000 mi above equator, ~24 hrs (earth’s rotation), elliptical orbit first, firing rocket engines at apogee then makes the orbit round

Delivery Rockets

used to launch satellites into orbit, velocities depend on type of orbit desired, must have enough fuel to reach required speed to overcome earth’s gravity, most of rocket’s weight in fuel, uses Newton’s 3rd Law of Motion (gases come out, push rocket forward) 1.) solid fuel rocket 2.) liquid fuel rocket (more mass) modern rockets combine both types of rocket

Rockets and Burnout Velocity

rockets work in stages, allows for rocket’s mass to decrease with successive stages, makes easier to accelerate rocket to its final speed/altitude

Burnout Velocity

rockets can keep accelerating until their fuel runs out, during free flight rocket is subjected only to the gravitational pull of the earth 1.) too little-you have become a ballistic missile 2.) too much-headed for deep space

Delivery Rockets

Saturn V Rocket: 2nd largest rocket ever launches, Apollo missions to the moon, used liquid fuel engines at all stages. SpaceX Starship Rocket: largest rocket ever, blew up mid test flight

Project Mercury

22 orbits, crew size of 1, Atlas rocket, orbit a manned spacecraft around the earth, investigated human’s ability to function in space, recovered both man and rocket safely

Project Gemini

Gemini 8, Neil Armstrong & David Scott, after performing a planned docking w/ an Agena rocket the main thruster malfunctioned, docked assembly entered into an uncontrolled spin, crew was able to separate their craft but had to use some of reserved propellant reserved to get back to Earth

Project Apollo

11 manned missions, 6 moon landings, crew size 3, project terminated due to lack of interest, main objective to walk on the moon

Apollo 1

capsule was to be pressurized w/ pure oxygen not N2/O2 mix, hatch was to open inward not out; 20 mins into flight a bare wire caused a spark which ignited the ethylene glycol used as a coolant, burning coolant caught other flammable material on fire; Gus noticed strange odor in his suit loop, high oxygen flow, communications link failed; fire in the cockpit, support crew runs, everyone inside dead; all tests taking place in pure oxygen are defined as hazardous, needs to be at normal pressure, hatch redesign, crew needs fire extinguisher

Apollo 11

successful moon landing

Apollo 13

planned as a precision lunar landing, one of two service module’s O2 tanks exploded, second tank survived but was leaking, everything had to be shut down to conserve, established Earth Day

International Space Station (ISS)

unified space exploration, in low earth orbit, delivery problems, too small of a crew, power from sun, have to deliver components in order when building in space

The U.S. Space Program

expensive, time consuming; very dangerous (2 have been lost)