Day 6: Exploration

Key moments in history: Sputnik was the first artificial Earth satellite. It was a 58 cm (23 in) diameter polished metal sphere, with four external radio antennas to broadcast radio pulses. The Soviet Union launched it into an elliptical low Earth orbit on 4 October 1957. It was visible all around the Earth and its radio pulses were detectable. The surprise success precipitated the American Sputnik crisis and triggered the Space Race, a part of the larger Cold War. The launch ushered in new political, military, technological, and scientific developments.

Sputnik itself provided scientists with valuable information. The density of the upper atmosphere could be deduced from its drag on the orbit, and the propagation of its radio signals gave information about the ionosphere.

The signals continued for 22 days until the transmitter batteries ran out on 26 October 1957. Sputnik 1 burned up on 4 January 1958, as it fell from orbit upon reentering Earth's atmosphere, after travelling about 70 million km (43.5 million miles) and spending 3 months in orbit.

Key Concepts:

Question of the Day: What are some of the biggest challenges to humans travelling for long periods of time in space?

Brief History of Space Exploration:

Eariest work on rocket engines designed for spaceflight occurred simultaneously during the early 20th century in three countries by three key scientists: in Russia, by Konstantin Tsiolkovski; in the United States, by Robert Goddard; and in Germany, by Hermann Oberth.

In the 1930s and 1940s Nazi Germany saw the possibilities of using long-distance rockets as weapons. Late in World War II, London was attacked by 200-mile-range V-2 missiles, which arched 60 miles high over the English Channel at more than 3,500 miles per hour.

After World War II, the United States and the Soviet Union created their own missile programs.

On October 4, 1957, the Soviets launched the first artificial satellite, Sputnik 1, into space. Four years later on April 12, 1961, Russian Lt. Yuri Gagarin became the first human to orbit Earth in Vostok 1. His flight lasted 108 minutes, and Gagarin reached an altitude of 327 kilometers (about 202 miles).

The first U.S. satellite, Explorer 1, went into orbit on January 31, 1958. In 1961 Alan Shepard became the first American to fly into space. On February 20, 1962, John Glenn’s historic flight made him the first American to orbit Earth.

“Landing a man on the moon and returning him safely to Earth within a decade” was a national goal set by President John F. Kennedy in 1961. On July 20, 1969, Astronaut Neil Armstrong took “a giant step for mankind” as he stepped onto the moon. Six Apollo missions were made to explore the moon between 1969 and 1972.

During the 1960s unmanned spacecraft photographed and probed the moon before astronauts ever landed. By the early 1970s orbiting communications and navigation satellites were in everyday use, and the Mariner spacecraft was orbiting and mapping the surface of Mars. By the end of the decade, the Voyager spacecraft had sent back detailed images of Jupiter and Saturn, their rings, and their moons.

Skylab, America’s first space station, was a human-spaceflight highlight of the 1970s, as was the Apollo Soyuz Test Project, the world’s first internationally crewed (American and Russian) space mission.

In the 1980s satellite communications expanded to carry television programs, and people were able to pick up the satellite signals on their home dish antennas. Satellites discovered an ozone hole over Antarctica, pinpointed forest fires, and gave us photographs of the nuclear power-plant disaster at Chernobyl in 1986. Astronomical satellites found new stars and gave us a new view of the center of our galaxy.

In April 1981 the launch of the space shuttle Columbia ushered in a period of reliance on the reusable shuttle for most civilian and military space missions. Twenty-four successful shuttle launches fulfilled many scientific and military requirements until January 1986, when the shuttle Challenger exploded after launch, killing its crew of seven.

Challenges to Future Space Travel

With our current technology it would take us about 10 years to travel to Pluto. Recent discoveries by the Kelper spacecraft have suggested that there are hundreds of potential habitable planets out there. Unfortunately, most are between 20-1000 light years away. That means that travelling at the speed of light, which is nearly 6 trillion miles a year, it would take 20-1000 years to get to one of those planets!!

To cover the enormous distances the future of space exploration will likely need to involve new propulsion methods. Chemical rockets are extreme inefficiency. Just to put the space shuttle into earth orbit (to reach 17,500 MPH), the rockets need to carry 15 times its weight in fuel – and that’s considered extremely efficient among other chemical-based rocket systems. To escape earth’s gravitational pull and explore our solar system (to reach 25,000 MPH), you would need significantly more fuel. If we wanted to leave our solar system and travel to our closest neighboring star in a reasonable time frame (say, 900 years) using standard chemical-based rockets, it would require 10137 kilograms of fuel – that is more fuel than exists on our planet. Thus, we need to look towards developing a better, more efficient method of propulsion.

If we do travel in space what effect will that have on our bodies?

Bones: In microgravity, astronauts no longer walk to get to different parts of the spacecraft, they float. This means that the bones in the lower part of the body that typically bear weight – the legs, hips and spine – experience a significant decrease in load bearing. This reduction leads to bone breakdown and a release of calcium, which is reabsorbed by the body, leaving the bone more brittle and weak. The release of calcium can also increase the risk of kidney stone formation and bone fractures. To put it in perspective, postmenopausal women who are untreated for bone loss can lose 1 to 1.5 percent of bone mass in the hip in one year while an astronaut can lose the same amount of hip bone mass in a single month. On missions outside Earth’s orbit, radiation exposure may also impact bone loss.

Muscles: Extended spaceflight results in less load on the leg muscles and on the back’s muscles used for posture. As a result, the muscles can begin to weaken or atrophy, and this could lead to fall-related injuries and accidents during exploration missions. Astronauts currently exercise to help maintain their muscle mass, but nutritional interventions designed to reduce the muscle loss may one day be added as a complement to the exercise program.

Fluid Shift: In space, the body no longer experiences the downward pull of gravity that distributes the blood and other body fluids to the lower part of the body, especially the legs. The fluids are redistributed to the upper part of the body and away from the lower extremities. While in space, astronauts often have a puffy face due to this fluid shift and legs that are smaller in circumference. The fluid shift to the head can also lead to a feeling of congestion.

Cardiovascular System: Although the cardiovascular system generally functions well in space, the heart doesn’t have to work as hard in the microgravity environment. Over time, this could lead to deconditioning and a decrease in the size of the heart. There is also a concern that space radiation may affect endothelial cells, the lining of blood vessels, which might initiate or accelerate coronary heart disease.

The Spine: Taller in Space: Astronauts get a bit taller in space. On Earth, the disks between the vertebrae of the spinal column are slightly compressed due to gravity. In space, that compression is no longer present causing the disks to expand. The result: the spine lengthens, and the astronaut is taller. One possible side effect is back pain that may be associated with the lengthening of the spine.

Inner Ear and Balance System: On Earth, a complex, integrated set of neural circuits allows humans to maintain balance, stabilize vision and understand body orientation in terms of location and direction. The brain receives and interprets information from numerous sense organs, particularly in the eyes, inner ear vestibular organs and the deep senses from muscles and joints. In space, this pattern of information is changed. The inner ear, which is sensitive to gravity, no longer functions as designed. Early in the mission, astronauts can experience disorientation, space motion sickness and a loss of sense of direction. Upon return to Earth, they must readjust to Earth’s gravity and can experience problems standing up, stabilizing their gaze, walking and turning. These disturbances are more profound as the length of microgravity exposure increases. The changes can impact operational activities including approach and landing, docking, remote manipulation, extravehicular activity and post-landing normal and emergency egress.

Sleep and Performance: Many factors – the loss of a 24-hour day/light cycle, a confined environment and work demands – can impact an astronaut’s ability to work well in space. In addition, exploration crews will have to shift their “body clocks” from the Earth day/night cycle to that of their destination. Scientists hope to help the crew increase their alertness and reduce performance errors through improvements to spacecraft lighting, sleep schedules and the scheduling of work shifts.

School Activity:

Human anatomy as affected by space. For each body system, draw its basic organs, and tissues. Label the organs and illustrate what happens when the body suffers from long term space travel.

Traveling to Mars Activity: What Your Body Needs to Know

Welcome Aboard – Planning Your Trip to Mars – A Simulation for Four Players

Your mission: To plan a trip to Mars while protecting the health and well-being of astronauts on board. Using the three level cabin design below as a starting point, outfit a spacecraft to take care of all needs you will have for a safe trip to Mars.

Here is the picture:

You have just landed on Mars, following a nearly six-month journey. You will have to stay on the Red Planet for nearly 19 months until the two planets line up again in their closest positions before you take off for the journey home. You will be away about 2-1/2 years! This is a long time to work and cooperate in a spaceship with its mission to investigate the Martian habitat. How would you ensure that all of the crewmates stay healthy for such a long mission?

Getting started: Pick a team of four, one doctor, one nutritionist, one space suit engineer, and one sports fitness professional. This will be your crew, along with the pilot and co-pilot. Cut out the cabin drawing at end of this assignment, and assign roles to each team member.

Their job:

To outfit their respective part of the cabin so that the crew has everything they need to maintain their health and fitness. The four areas of the ship’s cabin needing outfitting are:

  1. Galley: Diet and nutrition specialist for all food, meals and dietary supplements
  2. Fitness center: Muscle retention and exercise, needs full line of space-ready sports equipment
  3. Extra vehicular activity: Astronaut suits and protection while on planet, starting with NASA Space Suit Design:
  4. Sick bay: Taking care of the primary body systems, need to program the ship’s virtual doctor to monitor the key body systems at risk during voyage

Background Information to Help Your Planning

  1. Facts to Know for Your Trip to Mars Average distance of Mars from Sun: 1-1/2 times farther than Earth Length of Mars year: 687 Earth days Length of Mars day: 24 hours, 37 minutes Mass (amount of matter it contains): About 1/10th of Earth’s Surface gravity compared with Earth: 0.38 (If you weigh 100 pounds on Earth, you will weigh only 38 pounds on Mars) Atmospheric pressure at Mars surface: Only about 1/100th (or less) of Earth’s Main gases in atmosphere: Carbon dioxide, with a bit of nitrogen, oxygen, and argon.
  2. Bone loss during space travel due to weightlessness “Tesch said results from a study conducted on muscle atrophy in space over a 17-day period showed a constant drop in muscle mass at the rate of 2 percent loss per week. Results indicated that women are generally more susceptible to muscle loss in space than men, though both genders are substantially affected.”
  3. How the Human Body Changes In Space – Living in Space

How to play: Your crew takes one copy of the Mars Explorer Design Card and fills it out for each specific section of the ship. Use your notes and ideas collected from earlier parts of this lesson to help. Divide the mid deck into four sections, and ask one team member to outfit it and determine the size of space needed. This will set up the dimensions for the ship. Cut the mid level and lower level sections out from the drawing below, and construct a full, 3-D ship, using two copies of the drawing to get all four parts of the ship outfitted.

Note: you are competing with the design and completeness of the other space ship crews in the room. When you have finished, tape the two pieces of the ship together.

Your Ship: The USA Mars Voyager

Cut out two copies of this drawing, using each copy to outfit two of the needed compartments. Once done, tape the two sheets together, placing newspaper inside to give the ship a fuller, 3-D appearance.

Video of the Day:

Video of the Day:

Links: - 45 years of space exploration - Future of space flight - Space exploration - mining space - Carl Sagan's beautiful thoughts on space exploration - The Drake Equation - The body in space - Living in Space - Beings Just not made for space