Dr. Henry Throop / University of Colorado
Astronomy 1110
June 30, 2000
Lecture 20: Spacecraft Design Workshop

Announcements
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Exam #2 (multi-choice, etc.)
Makeup HW's
HW #5 -- today hopefully!
  Due Thursday, not Wednesday
Observing @ Walker

Monday: No class
Wednesday: Observing
Wednesday: Astrobiology (ch. 13.4-13.6)
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Worksheet & project

Spacecraft lecture
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  Can learn a lot with telescopes
  Big telescopes
  Different frequencies
    Visible -- like waht we see
    Infrared, for heat, and molecules (water, methane -- e.g., greenhouse gases)
    Ultraviolet -- for energetic light
    Radio -- for very cool things, or big things like pebbles, or looking thru clouds
    X rays -- really energetic, like black holes, galaxy centers

  Sometimes, even if we build a bigger telescope, it doesn't do the job: need to get 
    closer!

  Move telescope to planet, not just build a bigger one.  Like looking at Omaha:
    can see skyscrapers thru binocs from flatirons, but not the best thing.
    Really better to travel there.

  Flyby: get on I-80, stick head out window, and use binocs

  Orbiter: actually go there, cruise the downtown

  Lander: Can sample it, can interact (buy burgers), play around on surface

Orbits

  Moving targets

  It's 99% an unpowered cruise.  It's a big hunk of metal!

  Earth - Mars line up every two years
    Mars Observer 1994, Mars 96, Mars 98, 2001 Lander, 2003 Lander, 2005 Mission
    Takes 9 months
    Bigger s/c -> longer to get there
      (just like CABBAGES: push smaller cabbage faster w/ same force)
 
  Inner solar system: real easy, since they're close!  Just head toward 'em.

  Outer solar system: further distances, colder, weaker radio signals, etc.

  Orbits: somewhat more complex than a Keplerian ellipse
    Gravity assist -- slingshot 
    Speeds up spacecraft, slows down Earth.  Can't get something for nothing!
    Typical speeds: 100,000 km/hr, 30 km/sec

This isn't the space shuttle!  Space shuttle only flies at 300 km above Earth.
As far away as Laramie.

Spacecraft
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  Has to be 100% autonomous
  Has to communicate remotely (radio -- DSN)
  Has to be 100% reliable - no stuck antennas, no servicing, no hit by meteoroids
  Has to be lightweight and cheap

Many parts:
  Radios
  Antennas
  Power sources
  Thrusters
  Gyroscopes
  Heat shields
  Computers
  Scient instruments
  Propellant

Mission Q's:
  Where to go
  What to focus on science-wise
  What instruments to do the job
  Big or small s/c (Hummer or civic (ie, lawnmower))
  Flyby or Orbiter
  To Earth or a distant planet
  Ground-based or space-based
  Airplane

  Lander, orbiter, balloon, probe
  Sample return mission
  Inner or outer SS
  1 or 2
  Redundant?

  Robotic or Human

  Spectroscopy, imaging

Instruments
  High-resolution imager (to focus on a certain area)
  Low-resolution imager (to map the whole planet, search for volcanoes, etc.)
  Infrared spectroscopy (to look at composition of rocks)
  UV spectroscopy (to look at atmospheric gases: hydrogen, etc.)
  Altimeter (to map height of the surface)
  Radar Mapper (to see through clouds)
  Magnetometer (measure magnetic field, probe core of planet)
  Dust detector (measure size, composition, speed of grains from a comet or planetary rings)


Lander
  Rock sniffer (to determine rock composition on ground)
  Shovel (to dig holes)
  Meteorology package (wind speed, temp, direction, etc.)
  Chemistry experiments (search for evidence of life)

Probe or balloon
  Encephalometer (measure gas density, structure, greenhouse effect, etc.)
  Gas chromatograph (measure gas composition)
  Doppler wind package (measure wind speeds as probe drops through a hurricane)
   
Sample return
  Bring back rocks (pick them up or drill them)
  Bring back atmospheric gases
  Bring back solar wind particles

Funding
  Distance: 3 months per AU
  Mass = # of instruments
  For every additional instrument, add $100 M and increase travel time by 25%
  For a probe, lander, or balloon: call it two instruments
  Mission ops: $10M/month
  Launch costs: $50M + $10M per AU + $10M per instrument
  Probability of failure: 1 in 3 for small mission (<=3 instruments)
                          1 in 6 for big mission (>3 instruments)

Goals
  Life in SS (Mars, Europa, Titan?)
  Origin of the SS (asteroids, comets)
  Whole Jovian System (moons, rings, mag. field, red spot, etc.)
  Sun (magnetic field, solar storms)
  Earth (radar, oceans, wind patterns, aurora, magnetic field)

Actual missions
  Deep Impact (dive-bomb Europa)
  Solar Wind sample return
  Comet sample return
  Comet hopper
  Microrovers
  Air bags on Mars
  Sample return from Earth (Mars in future)
  Rovers on Mars
  JMEX -- Jupiter telescope in Earth orbit
  Mega-missions: Galileo, Cassini, Voyagers
  Asteroid orbiter