space expoloration

Astronomy Notes

Importance of Studying Space

Why Space Exploration Matters

• Helps humans understand planets, moons, asteroids, and the universe.

• Studies of planets like Mars and Venus help scientists understand climate change and planetary evolution.

• Satellites:

  • monitor Earth’s climate

  • track dangerous asteroids

  • predict solar flares that disrupt communication systems

Benefits to Society

Space exploration led to technologies such as:

• artificial limbs

• scratch-resistant lenses

• LEDs

• fire-resistant materials

• improved baby food

• medical technologies

Long-Term Human Survival

• Colonies on the Moon or Mars could protect humanity from:

  • asteroid impacts

  • nuclear war

  • global catastrophes

NASA Discovery Program

Purpose

NASA Discovery Program

• Began in 1992.

• Uses smaller, unmanned missions.

• Explores:

  • planets

  • moons

  • comets

  • asteroids

Important Discovery Missions

NEAR (Near Earth Asteroid Rendezvous)

• First spacecraft to orbit and land on an asteroid.

• Explored asteroid:

  • 433 Eros

• Created first 3D asteroid model.

• Studied craters, ridges, dust, and composition.

Mars Pathfinder

• Delivered the rover:

  • Sojourner

• Studied:

  • Martian atmosphere

  • geology

  • climate

• Suggested ancient Mars once had:

  • liquid water

  • thicker atmosphere

Lunar Prospector

• Studied:

  • Moon’s gravity

  • magnetic field

  • composition

• Found evidence suggesting possible ice near lunar poles.

Deep Impact Mission

• Sent impactor into comet:

  • Tempel 1

• Found:

  • water ice

  • organic molecules

• Suggested comets may have helped bring organic materials to Earth.

Mars Exploration Program

Goals

1. Determine whether life ever existed on Mars.

2. Study Martian climate.

3. Map Martian geology.

4. Prepare for future human missions.

Important Missions

• Mars Odyssey

• Mars Reconnaissance Orbiter

• Mars Phoenix

• Curiosity

• Spirit

• Opportunity

Human Spaceflight

Definition

Human travel into space using crewed spacecraft.

First Human in Space

Yuri Gagarin

• Soviet cosmonaut

• April 12, 1961

Apollo Program

Apollo program

• Sent humans to the Moon.

Challenges of Human Spaceflight

• radiation exposure

• zero gravity

• medical emergencies

• need for food, water, oxygen

Advantages of Human Missions

• Humans adapt quickly in emergencies.

• Flexible problem-solving.

• Greater inspiration and public interest.

International Space Station (ISS)

International Space Station

Partner Agencies

• NASA

• Roscosmos

• JAXA

• European Space Agency

• Canadian Space Agency

ISS Facts

• First module launched: 1998

• First crew arrived: 2000

• Completed: 2011

• Orbits about 220 miles above Earth

Research on ISS

• effects of zero gravity

• plant growth in space

• medicine and biology

• protein crystal growth

• fuel efficiency studies

• meteorology and space weather

Effects of Zero Gravity on Humans

• bone density decreases

• fluids move toward head

• muscles weaken

Robotic Missions vs Human Missions

Advantages of Robotic Missions

• cheaper

• no life support needed

• less radiation protection required

• spacecraft can be abandoned after mission

Advantages of Human Missions

• faster decision-making

• creative problem-solving

• stronger emotional and cultural impact

SETI (Search for Extraterrestrial Intelligence)

SETI Institute

Goal

Search for intelligent alien civilizations using electromagnetic signals.

Methods

• radio telescopes

• antennas

• signal analysis

Famous Projects

• Project Cyclops

• Project Phoenix

• SERENDIP

• SETI@home

• Allen Telescope Array

Drake Equation

Created by:
Frank Drake

Used to estimate intelligent civilizations in the galaxy.

N=R∗⋅fp⋅ne⋅fl⋅fi⋅fc⋅LN = R^* \cdot f_p \cdot n_e \cdot f_l \cdot f_i \cdot f_c \cdot LN=R∗⋅fp​⋅ne​⋅fl​⋅fi​⋅fc​⋅L

Variables

• R∗R^*R∗: rate of star formation

• fpf_pfp​: fraction of stars with planets

• nen_ene​: planets suitable for life

• flf_lfl​: planets where life develops

• fif_ifi​: planets where intelligent life evolves

• fcf_cfc​: civilizations that communicate

• LLL: lifespan of detectable civilizations

Exoplanets (Extrasolar Planets)

Definition

Planets orbiting stars outside our solar system.

First Discovery

• 1992

Methods of Detecting Exoplanets

Radial Velocity Method

Measures star movement caused by gravitational pull of planets.

Transit Photometry

Measures dimming of starlight when a planet passes in front of a star.

Pulsation Timing

Measures timing changes in pulsar signals.

Direct Imaging

Photographs planets directly using infrared radiation.

Microlensing

Detects planets through gravitational bending of light.

Habitable Zones

Definition

Region around a star where liquid water may exist.

Requirements for Habitability

• suitable temperature

• atmosphere

• possible greenhouse effect

• stable orbit

Inner Boundary

Too hot:

• runaway greenhouse effect

• water evaporates

Outer Boundary

Too cold:

• water freezes

Star Mass and Habitability

High-Mass Stars

• short lifetimes

• not enough time for advanced life to evolve

Small Stars

• live longer

• habitable zones very close to star

• tidal locking may occur

Galactic Habitable Zone

Definition

Region in the galaxy where conditions may support life.

Problems Near Galactic Center

• too many nearby stars

• higher supernova risk

Problems Far from Center

• fewer stars and heavy elements

Key Vocabulary