Below you will find related activities for today's topic of space exploration. Through the live webinar with a NASA engineers and exploring the Launch Pad you'll learn so much about what's above our own heads!
NOTE: There is A LOT of information here on the Launch Pad. Older youth will need to read everything on the Launch Pad to complete advancements. Younger youth can explore as much as they want.
Make sure to check out Mission Control to get any worksheets for today you might need to complete requirements for your rank or merit badge.
WEBINAR WITH NASA
Find the recorded webinar with Al Menendez from NASA below. NOTE: there is no presentation for the first two minutes as we waited for participants to get into the meeting.
Engineer Al Menendez is an Avionics Test Engineer for NASA. Avionics Test
Engineers design, develop, and test aircraft and spacecraft avionic
instrumentation. They also conduct research to address problems associated
with flight safety systems, landing gear and electronic navigation systems. Al
and his team work specifically on the Commercial Crew Program which is a
partnership to develop and fly human space transportation systems. Sound
familiar? The Commerical Crew Program in partnership with SpaceX launched U.S. astronauts into space from U.S. soil for the first time on May 27, 2020!
Watch the launch and explore the pre-camp mission if you haven't already here.
WHY EXPLORE SPACE?
Space is mysterious. We explore space for many reasons, not least because we don’t know what is out there, it is vast, and humans are full of curiosity. Each time we send explorers into space, we learn something we didn’t know before. We discover a little more of what is there. When you are on a hike, have you ever wondered what lies around the next bend in the trail, or beyond the next ridge, or down in the valley below? If so, then you will understand the thrill of sending a spacecraft to a world no human has ever seen.
Space has beckoned us, from early observers such as the Aztecs, Greeks, and Chinese; to 15th-century seafarers like Christopher Columbus and 17th-century astronomers including Galileo Galilei; to today’s Boy Scouts. The stars and planets in the sky have helped us shape our beliefs, tell time, guide our sailing ships, make discoveries, invent devices, and learn about our world. When electricity, airplanes, rockets, and computers came on the scene, some people realized it would be possible to put machines and people into space. No longer would we be limited to observing the wonders of space from the ground. Now we could enter and explore this curious environment. The “final frontier” could be opened. However, it proved complicated and expensive to build a rocket to put objects into orbit around the Earth. In the mid-20th century, only two countries had the knowledge, workforce, and money to do it—the Soviet Union and the United States. The Soviet Union showed its might by launching a small sphere into orbit. The Soviets’ success with Sputnik 1 on Oct. 4, 1957, began the “space race” between the two countries and launched the Space Age.
For more than 10 years, the United States and the Soviet Union competed by launching vehicles, animals, and people into space. The United States achieved its goal of landing men on the Moon by the end of the 1960s. Meanwhile, the Soviet Union built space stations to have a permanent presence in space.
We learned many new things from space missions focusing on science and education. Astronauts collected rocks from the Moon and did medical and scientific experiments above Earth’s atmosphere. Robotic spacecraft visited other planets. People watched on television as an astronaut hit a golf ball on the Moon and when a rover sniffed at a Martian rock. Space looked like fun!
Some business people looked beyond the fun and adventure of space exploration. They saw space as a chance to make money and satisfy society’s needs. The commercial satellite industry blossomed in the 1980s and into the 1990s, when constellations of satellites began to provide increasingly affordable global coverage.
Today, our ability to place satellites in orbit gives us many benefits. Seeing Earth’s atmosphere from space, meteorologists can forecast weather and warn people of dangerous storms more accurately than ever before. Looking down on the land and the ocean from space, we have found natural resources and seen disturbing evidence of their careless destruction. Communication satellites help tie the world’s population together, carrying video, telephone, computer, and Internet data for individuals, schools, governments, and businesses.
HISTORIC CREWED MISSIONS
In 11th century China, inventors and scholars developed gunpowder. One Chinese scholar packed a tube with gunpowder and sealed off one end, then someone realized this “fire work” could become a weapon, and the fire arrow was invented.
The first recorded use of rockets in war was in the year 1232 when the Mongols laid siege to the Chinese City of Kaifeng. The Chinese chased off the Mongols with a barrage of fire arrows. After the battle, the Mongols developed their own rockets. Some historians believe the Mongols introduced gunpowder and rockets to Europe.
From the 15th through the 17th centuries, cannons replaced rockets as military weapons. During the 18th century, rockets made a comeback thanks to William Congreve, an English inventor. His rockets helped the English win battles against Denmark, France, and Prussia. Francis Scott Key immortalized Congreve’s weapons when he wrote of “the rockets’ red glare” during the British attack on Fort McHenry in Baltimore Harbor during the War of 1812. Although the rocket became an instrument of war, a few dreamers of the 19th and 20th centuries saw it as a method of transportation.
Could people fly into space on a rocket? As the Industrial Revolution introduced new technology to the public, these dreamers used a new form of fiction—science fiction to express their ideas of traveling beyond Earth in ways that might actually be achievable.
Jules Verne (1828–1905) was born in Nantes, France. He went to Paris to study law. Instead, inspired by balloons, airships, and other new inventions, he began to write science fiction stories. He wrote From the Earth to the Moon (1865), Around the Moon (1870), and Around the World in Eighty Days (1873). In his novel From the Earth to the Moon , a giant cannon in Florida launches the space capsule. The astronauts, initially on an incorrect trajectory, execute a propulsive maneuver that puts them on a free-return trajectory. This allows them to circle the Moon and then land in the Pacific Ocean, where an American naval vessel recovers the crew and capsule. Verne told this story 100 years before the Apollo missions. Jules Verne is considered the father of modern science fiction.
Konstantin Tsiolkovsky (1857–1935) was a Russian teacher and scientist who wrote science fiction stories of interplanetary travel that featured real-world technical and scientific issues. He wrote about using liquid propellant to power rocket ships and about the need for spacesuits to protect people in the vacuum of space. He is credited with being the first to work through the mathematics of the “rocket equation” that serves as the foundation of spaceflight, and even considered a tower from Earth to geostationary orbit, which would be called a space elevator today. He is most noted for his quote “Earth is the cradle of mankind, but one does not stay in the cradle forever.”
Robert A. Heinlein (1907–1988) served as a U.S. naval officer aboard the first modern aircraft carrier, the USS Lexington. Due to health reasons, he retired from the Navy in 1934 and focused on science fiction writing, becoming widely regarded as the “dean of science fiction writers.” His novel The Moon Is a Harsh Mistress describes a subsurface lunar colony and electromagnetic launchers 40 years before any similar system existed. Many of his young people’s novels were first published as series, such as “Farmer in the Sky,” which was published as “Satellite Scout” in Boys’ Life magazine. A large number of space program supporters credit Heinlein with introducing them to the topic.
Arthur C. Clarke (1917–2008) wrote fiction and nonfiction for more than 60 years. In 1936, he joined the British Interplanetary Society, where he published their journal and began to write science fiction stories. He served in the Royal Air Force during World War II and tested radar systems. After the war, he returned to school and received degrees in physics and mathematics. In 1945, he published a paper titled “Extraterrestrial Relays” that laid down the principles of modern communications satellites in geostationary orbit, which is sometimes referred to as the Clarke Orbit in his honor. Clarke’s space-related works of fiction include the short story “The Sentinel,” which was turned into the movie 2001: A Space Odyssey (1968). His novels include Earthlight, Islands in the Sky, The Sands of Mars , and The Fountains of Paradise .
Dr. Gerard K. O’Neill (1927–1992) was born in Brooklyn, New York. He served in the Navy during World War II and earned a doctorate in physics at Columbia University. In 1954, he joined the faculty of Princeton University as a physics professor, where his work led to the invention of the colliding-beam storage ring for particle accelerators. Dr. O’Neill envisioned the development of space colonies constructed mainly of materials from the Moon and asteroids—one of the earliest ideas for space industrialization. His book The High Frontier (1977) popularized the idea of a giant space colony at the Earth-Moon L5 point and led to the creation of the L5 Society, which was devoted to making space colonization a reality. Dr. O’Neill contributed to the mass driver, which would magnetically levitate and accelerate supplies from the Moon and asteroids to the construction site he envisioned at L5. The L5 Society merged with Wernher Von Braun’s National Space Institute in 1987 to form the National Space Society. The Makers After the Wright brothers ushered in the age of flight, several rocket scientists laid the foundations for the Space Age.
Dr. Robert H. Goddard (1882–1945), born in Worcester, Massachusetts, is considered the “father of modern rocketry.” In 1907, while a student at Worcester Polytechnic Institute, he fired a rocket engine in the basement of the physics building, getting the attention of school officials. Seven years later, he patented his rocket inventions. In 1920, he published “A Method of Reaching Extreme Altitudes,” in which he suggested using rockets to carry weather instruments aloft. Dr. Goddard developed a rocket using liquid fuel and launched a liquid-fueled rocket that went faster than the speed of sound. He developed the first practical automatic steering device for rockets.
Sergi Korolev (1907–1966) was born in Zhitomir, Russia. He joined the developing field of aviation as a teenager and later studied engineering. He joined the developing field of aviation as a teenager and later studied engineering. After reading the works of Tsiolkovsky, he formed the Moscow Group for Study of Reactive Motion in 1931 and helped form the Rocket Research Institute in 1932. He was sent to a gulag in 1938 as part of Joseph Stalin’s great purges. By 1942, many technically adept prisoners were recruited to contribute to the war effort, including Korolev. At the end of World War II, Russian leaders realized the importance of developing rocket technology, and Korolev became a valuable member of the Soviet space program. During his top-secret career, he directed the launching of the first rockets into orbit, the Vostok, Voskhod, Molniya (now Soyuz), and Zond spacecraft, and probes to the Moon, Mars, and Venus. His death in 1966 was a crucial blow to the Soviet’s Moon program.
Dr. Wernher von Braun (1912–1977) was born in Wirsitz, Germany. Inspired by a race car driver when he was 12, von Braun attached six rockets to a coaster wagon and lit the fuses. The wagon careened around his backyard, emitting a fountain of sparks. The commotion attracted the police, who took him into custody. Von Braun became interested in space exploration by reading the science fiction of Verne and H.G. Wells and received his doctorate in aerospace engineering in the early 1930s. Familiar with Dr. Goddard’s work, von Braun designed and built Germany’s V-2 missile during World War II. At the end of the war, the U.S. Army realized the importance of Dr. von Braun’s work. He was brought to the United States with more than 500 fellow scientists and with many V-2 missiles and components under Operation Paperclip. He led the Army missile development program and launched the first U.S. satellite, Explorer 1 , in 1958. His crowning achievement was the development of the Saturn class of rockets that carried the Apollo astronauts to the Moon.
Steve Squyres (1956–) was raised in Wenonah, New Jersey. He is a professor of astronomy at Cornell University, focusing on large solid bodies in the solar system. He served on the Voyager imaging science team and was on the teams for Magellan, Mars Observer, and the Russian Mars ’96 mission. He is currently principal investigator for the long-serving Mars Exploration Rovers mission, as well as on the teams of Mars Express, Mars Reconnaissance Orbiter, and Odyssey and the imaging team for Cassini. He published Roving Mars: Spirit, Opportunity, and the Exploration of the Red Planet in 2006.
The “doers” were pilots who became astronauts. Among them were those who walked on the Moon and piloted the space shuttle.
U.S. Sen. John Glenn (1921–2016), was born in Cambridge, Ohio. While John Glenn is
not an Eagle Scout, his son is and John is a Silver Buffalo recipient in the BSA. He received
his aerospace engineering degree, joined the Navy during World War II, and earned his
wings as a Marine aviator. Glenn flew combat missions in World War II and Korea. He
attended Navy test-pilot school and became one of the original Mercury astronauts. He was
the first American to orbit Earth, in the Friendship 7 Mercury capsule on Feb. 20, 1962. He
served as senator from Ohio for 24 years. Glenn returned to space on a space shuttle mission in 1998, becoming (at age 77) the oldest person to fly in space.
Alan Shepard (1923–1998) was born in East Derry, New Hampshire, and graduated from the Naval Academy. He flew aircraft carriers during World War II. Shepard later attended test-pilot school and was selected as one of the original Mercury 7 astronauts in 1959. He was the first American to fly in space, on a Mercury suborbital mission in May 1961. Shortly after his flight, an inner-ear problem grounded him. An operation corrected the problem, allowing Shepard to lead the Apollo 14 lunar-landing mission. He hit a golf ball on the Moon that traveled 900 yards—a record that still stands. Suborbital means “not completing a full orbit.”
Neil Armstrong (1930–2012) was born in Wapakoneta, Ohio, and earned his aerospace engineering degree from Purdue University. Neil Armstrong is an Eagle Scout! After serving as a naval
aviator, he went to work for the government as an engineer, a test pilot, and then
as an astronaut. Armstrong was selected as a Gemini astronaut and commanded
the Gemini 8 mission. Then he went into the Apollo program. On July 20, 1969, as
commander of Apollo 11 , Armstrong became the first man to set foot on the
Buzz Aldrin (1930-present) is an American engineer, and former astronaut and fighter pilot. Aldrin made three spacewalks as pilot of the 1966 Gemini 12 mission, and as the lunar module pilot on the 1969 Apollo 11 mission, he and mission commander Neil Armstrong were the first two humans to land on the Moon. He was a Scout, achieving the rank of Tenderfoot Scout.
John W. Young (1930–2018) holds the distinction of being the only astronaut to fly Gemini, Apollo, and space shuttle missions. Born in San Francisco, he earned his degree in aeronautical engineering from Georgia Tech in 1952, joined the Navy, and became a test pilot. He flew on the first Gemini flight in 1965, commanded Gemini 10 in 1966, and was the command module pilot of Apollo 10 , orbiting the Moon alone while his crewmates tested the lunar module. In 1972, he landed on the Moon and drove the Apollo 16 rover. Young commanded the first space shuttle flight in 1981.
William Cameron "Willie" McCool (1961 – February 1, 2003), an Eagle Scout, was an American naval officer and aviator, test pilot, aeronautical engineer, and NASA astronaut, who was the pilot of Space Shuttle Columbia mission STS-107. He and the rest of the crew of STS-107 were killed when Columbia disintegrated during re-entry into the atmosphere. He was the youngest male member of the crew. McCool was posthumously awarded the Congressional Space Medal of Honor.
Robert Bigelow (1945–), a real estate developer, adapted NASA’s technology relating to inflatable habitats, which was part of the development of the International Space Station, and applied it to the concept of orbital facilities that could be leased by private interests. Bigelow Aerospace launched its first spacecraft, Genesis I, in 2006, followed by a larger Genesis II in 2007. Since then, they have provided invaluable data on how the inflatable spacecraft will behave in orbit. NASA is scheduled to test an inflatable module at the International Space Station in 2015.
Peter Diamandis (1961–) is a serial entrepreneur who has been involved in the creation of a number of important elements in the broader space community, including the International Space University, Students for the Exploration and Development of Space, and Zero-G Corp., which provides micro-, lunar, and Martian gravity parabolas to customers. He established the X Prize Foundation, which offers monetary awards designed to spur innovation in space exploration and a number of other fields.
Elon Musk (1961–), the cofounder of Internet transaction company PayPal, formed Space Exploration Technologies (SpaceX) in 2002 to build rockets that could inexpensively carry payloads to low Earth orbit and geosynchronous orbit. After years of successful rocket launches, the company began transporting cargo to the International Space Station in October 2012 in its Dragon spacecraft.
THE WAY THINGS WORK
Space exploration has been a reality since the late 1950s. Space-age words such as rocket, satellite, and orbit have become part of nearly everyone’s vocabulary. While many people use these words, few really understand the important concepts behind them, such as how a rocket works, how a satellite stays in orbit, or how pictures taken of other planets arrive on Earth.
PHYSICAL LAWS OF SPACE FLIGHT
In the 17th century, a great English mathematician and scientist named Sir Isaac Newton developed the basics of modern physics. He formed the theories of gravitation when he was only 23 years old. Some 20 years later, he presented his three laws of motion. These three laws explain how a rocket is able to work and how satellites and spacecraft are able to get into orbit and stay there.
NEWTON'S THREE LAWS OF MOTION
An object in motion tends to stay in motion, and an object at rest tends to stay at rest, unless the object is acted upon by an outside unbalanced force.
Force equals mass times acceleration.
For every action there is an equal and opposite reaction.
These three laws of motion help make it easier to understand how rockets, satellites, and spacecraft work. For Scouts BSA/Venturing youth, learn more about each law in the Space Exploration Merit Badge pamphlet or online.
HOW ROCKETS ARE PROPELLED
Rockets are driven by engines that obey Newton’s three laws of motion. While a rocket sits on the launchpad, it is in a state of rest because all forces are balanced. When the rocket engine fires, forces become unbalanced (first law). As exhaust rushes downward out of the engine, an upward thrust is produced because of action-reaction (third law). The strength of that thrust is determined by the amount of matter expelled by the engine and how fast the matter is expelled (second law). Forcing the exhaust through a small opening called a nozzle increases the speed of the exhaust, producing more thrust. Imagine using a garden hose with a nozzle attachment. With the nozzle wide open, the water streams out and lands a few feet away. By shrinking the nozzle opening, you force the water to move faster and it lands farther away. The greater the velocity, the greater the thrust. You can feel the thrust of the garden hose if you hold it. The same principle applies to rocket engines, which come in many varieties based on the type of fuel used. Some types of engines used on today’s spacecraft include solid propellant engines, liquid propellant engines, hybrid engines, and ion engines. Nuclear engines, solar sails, mass drivers, and other kinds of “futuristic” engines are being studied or developed. For Scouts BSA/Venturing youth, learn more about engines in the Space Exploration Merit Badge Pamphlet.
HOW SATELLITES STAY IN ORBIT
Isaac Newton reasoned that it was the force of gravity—not its absence—that kept the Moon in orbit around Earth. Artificial satellites also operate under the same Newtonian laws. To explain Newton’s reasoning, think about what happens when you throw a ball. Imagine you are standing in a big field and throw a baseball as hard as you can. The ball might travel 100 feet before gravity pulls the ball down to the ground.
Now imagine you are standing on Mount Everest. You throw the baseball and it travels
parallel to Earth for some distance before it falls to Earth. Each time you throw the ball, you
increase the thrust and the ball travels farther. If you could throw the ball fast enough (and if
you ignore friction from the atmosphere), the ball would fall at exactly the same rate that the
curve of Earth falls away from the ball. This situation is called free fall . The ball would continue
traveling parallel to Earth’s surface, achieving orbit. This is the basis for how satellites stay in orbit.
All satellites ride on rockets to get into orbit. Satellites as large as several tons make it safely into orbit on a regular basis.
Rockets travel straight up at first. This is the quickest way to get the rocket through the thickest part of Earth’s atmosphere. Once above the atmosphere, the rocket control mechanism brings the rocket to a course that is parallel to Earth’s surface while the rocket accelerates to the velocity needed for that satellite to remain in orbit. This velocity is determined by the weight of the satellite and the altitude of the orbit to be achieved.
Orbital velocity is the speed needed to reach a balance between gravity’s pull on the satellite and the satellite’s inertial tendency to keep going. If too much velocity is imparted to the satellite, it will escape from Earth and enter into a Sun-centered (heliocentric) orbit. If too little velocity is imparted to the satellite, gravity will pull it back to Earth. At the correct speed, the satellite will be in perpetual free fall. The higher the orbit, the longer the satellite can stay in orbit. At lower altitudes, a satellite runs into traces of Earth’s atmosphere, which creates drag. The drag causes the orbit to decay, or decrease, until the satellite falls back into the atmosphere and burns up.
Space pictures have evolved along with the digital technology of the computer, Internet, and cell phone. Early space pictures were made on film, which had to be returned to Earth and processed. Today, scientists use CCDs, or charge-coupled devices, to gather the information digitally. Early video was grainy and barely usable. Images taken by spacecraft consist of many tiny squares called pixels. As space probes ventured farther into space, scientists needed better ways to record, store, and transmit pictures. Information scientists developed a coding system that treats each picture frame as a grid with numbered squares. Each square is a picture element—pixel, for short. Every pixel has its own address of numbers in the grid that gives the pixel’s row and column.
When a space probe’s sensor views an object, it senses the brightness or shade of each pixel in the scene. Shades are measured on a gray scale, which is a gauge of the shades of gray from pure white to pure black. Let’s assume we have a simple gray scale with only five shades. Each shade is numbered. White is 01, light gray is 02, and so on to solid black, 05. The sensor assigns each pixel the number that corresponds to the shade sensed.
These numbers are stored in a computer memory and then transmitted to the waiting scientists. The receiving computer is programmed to arrange the pixels into a grid, show the correct shade of gray for each picture element, and reconstruct the picture row by row. In early missions where the data transmission rate was slow and computer memory limited, it might take several minutes to display one picture frame. Mariner 4 , when it photographed Mars in 1965, made images 200 x 200 pixels in size. Each complete image took nearly 9 hours to reach Earth. In contrast, the Clementine lunar mission in 1994 returned 2 million images in 21/2 months, averaging more than 1,000 images an hour.
Did you know?
Because of this constant state of everything falling together at the same speed, the satellite and everything aboard seems weightless. That is why astronauts can float inside the International Space Station.
Long ago, the Greeks noticed bright, starlike objects moving among the stars. These “wanderers” included the Sun, Moon, Mercury, Venus, Mars, Jupiter, and Saturn. People thought all these objects circled Earth, which was thought to be at the center of the universe. In the 16th century, Nicolaus Copernicus determined that Earth was a planet, too, and that the six known planets went around (orbited) the Sun while the Moon circled Earth. Then, in 1610, Galileo Galilei turned a newly invented instrument—the telescope—toward the heavens. He looked at Jupiter, and what he saw astounded him. Through the telescope, Jupiter was not a wandering point of light, but a round disk with four small starlets (moons) circling it. Earth’s Moon was not a smooth shadowy ball, but a sphere pockmarked with craters and laced with cracks and ridges. Venus went through phases like the Moon, Saturn had bumps on its sides (the rings), and the Sun had spots on its surface. The worlds of outer space were more exciting than anyone had imagined.
Almost 350 years later, when people learned how to send objects—spacecraft—into space, a new era of exploration began. Scientific instruments and cameras could now be carried above the filtering effects of Earth’s atmosphere, providing clearer views of outer space than ever before. Spacecraft could go to those faraway places Copernicus and Galileo barely knew.
SPACE PROBES: TOOLS OF THE SPACE AGE
A spacecraft is any vehicle that flies in outer space, whether or not it carries people. An unmanned spacecraft is technically known as a space probe. Such probes have been used since the late 1950s to explore other worlds, large and small, in our solar system.
A space probe is a clever arrangement of mechanical and electronic parts packed together inside a sturdy, compact box or shell that is launched aboard a rocket. Once in space, the box opens and the various parts (components) begin to operate. Each group of components plays an important role toward accomplishing the mission—controlling the spacecraft, taking measurements of its surroundings, or communicating with people on Earth, thousands or millions of miles away.
Scientific instruments aboard a spacecraft detect and measure what’s out there. Almost every probe carries one or more cameras to capture images of the object it visits. Some probes may have devices to measure radiation, temperature, and magnetic fields. Those that land on an alien surface may carry a miniature weather station and a scoop to sample the soil. Other devices may be designed to detect certain chemical elements or compounds, such as water.
A computer system stores commands that direct the other components to function and to control the craft. The computer also collects the information gathered by the instruments and gets it ready for transmission to Earth. When it is time to send the data to Earth, an antenna aims radio signals in the right direction. Another antenna receives signals from Earth.
To do all these things, a spacecraft needs a power supply. The probe may have solar cells to convert sunlight into electricity. Or it may have a nuclear-powered generator to provide electricity, especially if it is visiting a planet far from the Sun. Because outer space is extremely cold, some power goes to a heater that keeps the spacecraft at the right temperature for the computer, instruments, and other components to operate. After the probe has been launched into space, altering its direction becomes necessary during millions of miles of travel. A set of small rockets (thrusters) is used to adjust the probe’s course or “put on the brakes” if the probe must go into orbit around a planet or land on an alien surface.
MISSIONS TO SPACE
ROBOTIC MISSIONS TO THE MOON
Many attempts were made before the first probe flew past the Moon. On Jan. 4, 1959, the Soviet Luna 1 impactor flew within 6,000 km of the Moon before entering an orbit around the Sun. Two months later, Pioneer 4 became the first U.S. probe to pass by the Moon, at a distance of 60,000 km, before also entering a heliocentric orbit. The Soviets achieved additional lunar firsts with the first hard lander, Luna 2 , which landed in Palus Putredinis in September of the same year, and Luna 3 a month later, which provided the first images of the lunar far side. As a consequence, all of the most easily photographed features bear Russian names.
After a number of failures on both sides over the next five years, the Ranger 7, 8 , and 9 missions returned more than 17,000 increasingly close-up images on their way to impacting the Moon’s surface in 1964 and 1965. In mid-1966, NASA achieved the first controlled landing on the Moon with Surveyor 1 . Four more Surveyor missions followed to research the lunar surface in anticipation of the Apollo landings. Five Lunar Orbiter spacecraft also mapped the lunar surface to provide greater detail on potential landing sites.
The Soviet Union continued to explore the Moon into the mid-1970s. Zond spacecraft flew around the Moon, took photographs, and returned to Earth with their payload. The Soviet Moon program also included several successful sample return missions and a pair of remote-driven rovers called Lunokhod (“moon walker”), which covered 10.5 km and 37 km of the lunar surface over a period of more than a year.
NASA scientists increasingly turned their attention to other destinations in the solar system, while lunar scientists worked through the enormous amount of data returned by Apollo. This led to a long dearth of lunar missions. The Japanese space agency conducted its first lunar mission in 1990 with the Hiten (meaning “celestial maiden” or “flying angel”) probe, which achieved limited success in conjunction with the deployed Hagoromo orbiter.
In 1994, the U.S. Department of Defense launched an experimental spacecraft named Clementine that orbited the Moon for 70 days, mapping its surface. It detected the possible presence of frozen water at the Moon’s south pole with an experiment that demonstrated the presence of hydrogen. In 1998, Lunar Prospector mapped the lunar surface in more detail, measured magnetic and gravity fields, and studied geological events. It also showed the presence of hydrogen near the poles. After one year, it was intentionally crashed near the south pole in the hope of revealing water ice.
The European Space Agency (ESA) launched its first mission to the Moon, SMART-1 , in 2003. This probe used an ion thruster, slowly spiraling the probe up out of Earth’s gravity well until it could be captured into the Moon’s gravitational sphere of influence. It arrived in late 2004 and began surveying to identify chemical elements in the lunar surface. It too was crashed into the Moon in hopes of excavating a debris plume with evidence of water.
In late 2007, Japan launched its Kaguya (“Moon maiden”) probe and China joined the roster of lunar visitors with its Chang’e-1 (“Moon princess”) probe. Both were designed to map the surface and identify the chemicals found there. A year later, India launched its first Moon probe, Chandrayaan-1 (“Moon vehicle”), which carried an international suite of scientific instruments. Then came NASA's Lunar Reconnaissance Orbiter (LRO) and Lunar Crater Observation and Sensing Satellite (LCROSS), which slammed a school bus–sized probe into the lunar south pole region to try to excavate a plume that was observed from Earth, and revealed a rich variety of chemicals, including water. In 2010, China launched Chang’e-2 .
NASA launched the Gravity Recovery and Interior Laboratory (GRAIL) mission in 2011 to study the Moon’s gravity fields and internal mass distribution. Under development for future launch are LADEE, Luna-Glob, Chang’e-3, Chandrayaan-2 , and the first node of NASA’s International Lunar Network (ILN).
Since 2011 there has been extensive research and funding to continue to send missions to the moon. See the full list.
UNVEILING VENUS AND MERCURY
Mysterious Venus, whose surface hides from Earth-based telescopes under a shroud of clouds, was the
first planet after Earth to be examined by a robotic spacecraft. The United States had Mariner 2 , after
orbiting the Sun for almost a year, approach and fly by Venus in December 1962. The spacecraft reported
the planet was over 900 degrees Fahrenheit, hotter than Mercury. The Soviet Union was bolder with its Venera
program, whose 16 probes intensively explored Venus between 1961 and 1983. Venera was the first spacecraft to probe the planet’s atmosphere, the first to land there, the first to photograph its surface, the first to analyze the soil, and the first to map the terrain. Starting with Venera 4 (1967), the spacecraft was two probes: a carrier that stayed up high and a lander that dropped toward the surface. But the dense Venusian atmosphere crushed each lander before it could land. Eventually, Venera 7 was built strong enough to safely descend. It lasted for 23 minutes on the surface of Venus in 1970. The United States then sent Mariner 10 , which achieved two goals. Three months after launch in November 1973, the probe flew by Venus and took many measurements of the atmosphere. With assistance from Venus’ gravity (like a slingshot), it sped onward to Mercury, the Sun’s closest planet. Mariner 10 , which photographed about 40 percent of Mercury’s surface, has been the only probe to visit there until the MESSENGER probe began flybys in 2008 and started orbiting the planet in 2011.
In the 1980s, Vega 1, Vega 2 , and Magellan visited Earth’s “sister” planet. The Vegas, identical 36-foot-long probes from the Soviet Union, reached Venus in June 1985. They dropped a landing capsule onto the surface, released a balloon into the atmosphere, and then got slingshot by the planet to intercept Halley’s Comet. The balloon carried instruments that measured atmospheric temperature, pressure, and wind speed. The lander took similar measurements and photographs, and analyzed the chemical makeup of the air and soil. Magellan was the first planetary spacecraft to be launched from the space shuttle (in May 1989). After entering a polar orbit around Venus in August 1990, Magellan spent more than four years mapping 98 percent of the hidden terrain using radar. Scientists returned to Venus in 2006, when the ESA’s Venus Express probe entered into a polar orbit around the planet. The probe revealed a thinner atmosphere than expected as well as evidence that the
planet may still be geologically active. NASA’s MESSENGER probe has made several close
approaches to Mercury, providing imagery to fill in the gaps left by Mariner 10 . In March
2011, it became the first spacecraft ever to orbit Mercury, where it has been studying the
composition and structure of the crust, among other things. The ESA has the BepiColumbo probe under development for launch in 2015 with arrival at Mercury in 2022.
MISSIONS TO THE RED PLANET
At the end of the 19th century, astronomer Percival Lowell focused a large telescope on Mars and reported seeing canals on its surface. People’s imaginations soared, but scientists had to wait until 1965 before a spacecraft flew to the Red Planet. Pictures from Mariner 4 revealed a surface covered with craters, similar to the Moon. The probe’s instruments found
Mars had a thin atmosphere of mostly carbon dioxide. Not a single canal or other sign of life was spotted.
Mariner 9 was the first U.S. spacecraft to orbit another planet, arriving at Mars in November 1971 to find a
dust storm enveloping the planet. The probe delayed taking pictures of the surface for several months until
the dust settled. After 349 days in orbit, Mariner 9 had transmitted more than 7,000 images, covering over 80
percent of the Martian surface. Notable features were river beds, massive extinct volcanoes, and a series of canyons that stretched more than 2,500 miles long. The probe found evidence of wind erosion, water erosion, weather fronts, clouds, and fog—but no life.
The Soviet Union turned its attention to Mars in the 1970s, beginning with the Mars 2 probe, which successfully arrived in November 1971, a few weeks after Mariner 9 . The Mars 2 spacecraft released a lander that descended into the raging dust storm and crashed. However, the orbiter took photographs and studied the atmosphere and surface. Mars 3 , which was identical to Mars 2 , had better luck. The vehicle landed safely and transmitted the first television pictures of the Martian surface for 20 seconds, then communication from the lander was lost.
Americans were excited when two Viking missions reached Mars in 1976. Each craft had two parts, an orbiter and a lander. Viking 1 landed on July 20, 1976, while Viking 2 settled on the other side of the planet six weeks later. While each orbiter took detailed photos and communicated with Earth, each lander communicated with Earth, each lander stood on three legs with large circular footpads and performed its duties. A camera took the first close-up image of the Martian surface—a footpad and a bunch of rocks. People were awestruck by Mars—its red boulders, red soil, and pinkish sky. Each Viking lander extended a long arm into the soil, scooped up samples, and dropped them into three chemical laboratories. The labs tested the soil to find chemicals that might come from a microscopic organism. The results of all these experiments were inconclusive, the scientists decided, meaning there was still much to learn about Mars.
Mars Pathfinder was the next spacecraft to arrive safely, landing on July 4, 1997. The craft bounced onto the Martian surface, its fall from space cushioned by inflated airbags. The craft was shaped as a tetrahedron—four triangular sides—so that when it stopped bouncing, the three sides standing up would fall open like a flower.
Aboard was a small rover (two feet long and one foot high) named Sojourner. Powered by a solar panel on its back, the rover rolled down a ramp and traveled close enough to the nearest rock for one of its instruments to touch the rock and determine its composition. Then the rover visited other rocks, large and small, around the lander. The rover was designed to last for seven days and the lander for 30 days; each operated for 83 days. A Mars probe was launched in 1996, arriving in September 1997. After establishing a nearly polar orbit, the Mars Global Surveyor began mapping the terrain in early 1999. Its original two-year mission lasted until 2006.
After the success of Mars Pathfinder , NASA launched Mars Climate Orbiter in December 1998 and Mars Polar Lander in January 1999. As Climate Orbiter tried to orbit the planet, an earlier miscommunication between NASA and a contractor that did not specify English or metric units triggered an error in the probe’s trajectory that plunged it too low into the atmosphere during its aerobraking maneuver, causing it to burn up. Months later, on Dec. 3, 1999, planetary scientists and space enthusiasts waited anxiously as Polar Lander began its descent into the Martian atmosphere. Since there had been no communication, there was no way to know what went wrong.
After 2000, scientists began to explore the Red Planet in a more robust and comprehensive
manner. NASA’s Mars Odyssey , which arrived in late 2001, mapped the global distribution
of near-surface ice on Mars, finding ice-rich ground extending far toward the equator from
the visible polar caps. It was still returning data in 2012. ESA’s Mars Express , which arrived
in late 2003, provided critical radar scans of the subsurface of Mars and studies of the
atmosphere and space environment around the planet and its moons. It also carried the
Beagle 2 lander to study the surface, but contact was lost with the lander after it separated from Mars Express.
In early 2004, the Mars Exploration Rovers (MER) Spirit and Opportunity arrived at Mars for a three-month mission to “follow the water,” looking for environments that had water in the past and might have been able to support life. Spirit proved that some of the planet’s rocks were formed in the presence of water in ancient Mars, and both rovers found numerous nickel-iron meteorites there. Communication was lost with Spirit in 2010, but Opportunity continued to return data in 2012.
Since Curiosity, many other rovers have taken the journey to Mars:
Mars Orbiter Mission in 2013 - still in operation
MAVEN in 2013 launched by NASA - still in operation
ExoMars Trace Gas Orbiter in 2016 - still in operation
Schiaparelli EDM lander in 2016 - Spacecraft failure
InSight in 2018 launhced by NASA - still in operation
MarCO in 2018 launched by NASA - Successful!
DISCOVERIES ABOUT MARS - THE RED PLANET
The entire north polar area of Mars may be a gigantic impact basin.
Mars has climate cycles similar to Earth’s.
Mars has methane in the atmosphere, which could be produced by underground bacteria or geological events.
Mars has millions of cubic miles of water frozen in its polar caps and in its crust near the poles. Early Mars probably had a huge ocean filled with icebergs and pack ice that covered its north polar area. Liquid water on the surface became rare as the planet lost atmosphere and got colder and drier.
Mars has a very weak magnetic field, which allows some of its air to leak into space more easily. Mars exploration continued in 2006 with the Mars Reconnaissance Orbiter and in 2008 with the Phoenix Mars Lander.
The Mars Science Laboratory named Curiosity was launched in August 2012. Its mission is to provide an intensive study of its landing zone as well as serve as a weather station with a suite of climate and meteorology instruments to provide a richer knowledge of how Mars’ atmosphere and climate works now, so we can better predict how it worked in the recent and distant past.
THE GRAND TOUR: EXPLORING THE OUTER PLANETS
Jupiter and Saturn have mystified people for centuries. What is that Great Red Spot? Why does Saturn have rings? How many moons circle each planet? The Pioneer and Voyager missions revealed those worlds to be more fascinating than expected. Pioneer 10 was the first spacecraft to travel through the asteroid belt. Some scientists feared the craft might hit an asteroid, but it reached Jupiter safely in December 1973. Pioneer 10 took the first up-close photographs of Jupiter, which showed the planet had colorful swirling bands. Photos revealed smaller white spots besides the Great Red Spot, which is a hurricane large enough to cover at least two Earths. The craft also measured Jupiter’s strong magnetic field and radiation belts. Pioneer 11 did the same, one year later.
Jupiter's Great Red Spot
JUPITER'S GREAT RED SPOT
The United States launched two Voyager probes in 1977. Voyager 1 reached Jupiter in March 1979. Voyager 2 arrived four months later. Each probe photographed the planet and its four largest moons—Io, Europa, Ganymede, and Callisto—in detail. Io has volcanoes and resembles a “pizza ball.” Europa has a cracked, icy surface (and possibly a liquid ocean beneath the ice). The probes discovered that lightning crackles in Jupiter’s cloud tops, a thin ring surrounds the planet, and it has many more moons than had been observed from Earth.
At Saturn in 1981, Voyager revealed the rings to be more complex and grand than expected. Dark spokes could be seen, and small moons were found that guided the ring material. Saturn’s largest moon, Titan, was also studied, though its atmosphere was too thick for cameras to see the surface.
While Voyager 1 headed out of the solar system, Voyager 2 took advantage of a rare alignment
of the outer planets. The spacecraft continued on to Uranus (1986) and then Neptune (1989),
achieving the “Grand Tour.” The craft detected faint rings around both gas giants and
discovered new moons.
A spacecraft named Galileo , launched from the space shuttle in 1989, visited Jupiter in 1995, using gravity assist from Venus and Earth. It released a small probe that plunged into Jupiter’s cloud layers and measured temperature, pressure, chemical composition, and other characteristics before the planet’s dense atmosphere crushed it. Its orbiter flew around Jupiter often and visited the major moons, collecting much data. Galileo survived for eight years in the Jovian system despite the harsh radiation. The Cassini mission to Saturn was launched in 1997, carrying ESA’s Huygens probe along for the long journey. After gravity-assist visits to Venus, Earth, and Jupiter, the robotic probe arrived at Saturn in June 2004. Six months later it released the Huygens probe for its descent to Titan. The Cassini orbiter spent the next four years studying Titan and Saturn’s rings and other moons. After 20 years in space — 13 of those years exploring Saturn — Cassini exhausted its fuel supply. And so, to protect moons of Saturn that could have conditions suitable for life, Cassini was sent on a daring final mission that would seal its fate. After a series of nearly two dozen nail-biting dives between the planet and its icy rings, Cassini plunged into Saturn’s atmosphere on Sept. 15, 2017, returning science data to the very end. Learn More with NASA.
WANDERING THROUGH SPACE
Not every robot space probe visits a planet. Some head to much smaller objects—comets and asteroids. When Halley’s Comet approached the Sun in 1986, some countries and space agencies launched probes to meet it. From the Soviet Union, two Vega spacecraft flew by the comet in March 1986 and took measurements on their way to Venus. A few days later, Japan’s Sakigake probe briefly passed by. Last and most daring was Giotto , a probe sent by the European Space Agency. Giotto traveled into the fuzzy white “head” of Halley’s Comet, a cloud of gas and dust surrounding the nucleus. More than 200 dust particles per second struck the craft. One dust grain (about a third of an ounce) knocked out communications with Earth for a short while, but the 9-foot-long cylinder-shaped probe survived its passage through the comet. Giotto found that the nucleus of the comet was about 9 miles long and 6 miles wide. NASA launched NEAR Shoemaker in February 1996. The craft’s name explained its objective: Near Earth Asteroid Rendezvous. It reached the small, potato-shaped asteroid Eros in February 2000 and became the first probe to orbit and land on an asteroid.
The spacecraft Deep Space 1 had no destination when it launched in October 1998. Its purpose was high-tech testing in outer space. One device tested was an ion engine, first of its kind, that performed better and longer than expected. Deep Space 1 ’s mission was extended to encounter a near-Earth asteroid in 1999 and Comet Borrelly in 2001. The Stardust probe's primary mission for its was to collect comet samples and return them to Earth for study. It flew by the comet Wild 2 (pronounced Vilt) in 2004, and in 2006 returned a canister of aerogel containing bits of comet dust, which included small amounts of stardust grains. The robotic probe visited comet Tempel 1 in 2011 to build on the Deep Impact dataset.
NASA’s Deep Impact probe was designed to look inside a comet. In mid-2005 it did so by hitting comet Tempel 1 with a copper impactor and then examining the plume of debris from that collision (including 250,000 tons of water). The probe visited comet Hartley 2 in November 2010. Its mission was further extended to visit asteroid 2002 GT in January 2020. ESA’s Rosetta probe is designed to provide long-term data collection of a comet, 67P/Churyumov-Gerasimenko. Launched in 2004, the probe is scheduled to arrive in 2014 after a series of gravity boost planetary flybys of Earth and Mars. It will then deliver a lander to study the comet surface in detail. Japan’s Hayabusa (“peregrine falcon”) probe was launched in 2003 to rendezvous with and collect samples from asteroid Itokawa, an asteroid so small that other objects tend to just settle up against it without creating a crater. Using an ion engine, it was able to catch up with and touch down on the asteroid to collect samples from the surface. These samples were returned to Earth by the spacecraft in mid-2010.
Dawn orbited Vesta for more than a year, from July 2011 to September 2012. Its investigation confirmed that Vesta is the parent of the HED (howardites, eucrites, and diogenites) meteorites, which Dawn connected to Vesta’s large south polar basin, a priceless cosmic connection between samples in hand and a singular event on a small planet. Vesta is small enough (about the same size as Saturn's moon Enceladus) to have been deeply scarred by the Rheasilvia impact that launched the HEDs, but large enough to have differentiated into an iron core, silicate mantle, and igneous crust. Dawn also found hydrated and carbon rich material on its surface supplied by impactors, a result that was unexpected based on pre-Dawn telescopic observations.
After its escape from Vesta and its journey onward, Dawn entered orbit around Ceres in March 2015. Dawn discovered that the inner solar system’s only dwarf planet was an ocean world where water and ammonia reacted with silicate rocks. As the ocean froze, salts and other telltale minerals concentrated into deposits that are now exposed in many locations across the surface. Dawn also found organics in several locations on Ceres’ surface. Dawn is currently in its second extended mission at Ceres, in an elliptical orbit that goes as low as 22 miles above Ceres’ surface.
WHAT ABOUT OUR SUN?
Let’s not forget the largest and most important member of the solar system. Several space probes have been sent into orbit to study our Sun. Some of the Pioneer series did so in the 1960s. Two Helios probes measured the solar wind in the mid-1970s.
Ulysses, launched in October 1990, was the first spacecraft to travel in an orbit nearly perpendicular (vertical) to the ecliptic plane . No human-made vehicle could produce the power to break out of the ecliptic plane on its own, so Ulysses relied on mighty Jupiter’s gravity to hurl it above that level. During its 18-year mission, it was able to fly over the Sun’s north and south poles, which had never been observed or measured in scientific detail before. SOHO is the Solar and Heliospheric Observatory. Launched in December 1995, SOHO was sent to study the nature of the Sun’s corona and inner structure, as well as detect the solar wind . During its mission, SOHO discovered more than 50 Sungrazing comets and made movies of coronal mass ejections , which produce dangerous radiation that can cause communication blackouts on Earth. SOHO was still returning data in early 2013.
Launched in late 2001, NASA’s Genesis mission was designed to collect particles of solar wind to return to Earth for study. After taking up station at the Sun-Earth L1 point that same year, it spent the next 28 months in collection mode using collector arrays of different materials as well as a bulk collector. The probe then used its ion engines to maneuver into a low-energy trajectory that swung it by the Moon and back to Earth, where it crashed into the Utah desert in 2004. Scientists were able to recover some of the arrays relatively intact and have been analyzing them since. STEREO , or Solar TErrestrial RElations Observatory, was launched in October 2006 to study coronal mass ejections. It consists of two observatories, one of which is ahead of Earth in its orbit and the other behind. NASA launched the Solar Dynamics Observatory (SDO) in early 2010 to geostationary orbit, where it collects data on our Sun with a focus on the magnetic fields and how they affect space weather. Contact with STEREO-B was lost in 2014, but STEREO-A is still operational.
In 2018, NASA launched the Parker Solar Probe. NASA's historic Parker Solar Probe mission is revolutionizing our understanding of the Sun, where changing conditions can propagate out into the solar system, affecting Earth and other worlds. Parker Solar Probe travels through the Sun’s atmosphere, closer to the surface than any spacecraft before it, facing brutal heat and radiation conditions to provide humanity with the closest-ever observations of a star.
In order to unlock the mysteries of the Sun's atmosphere, Parker Solar Probe uses Venus’ gravity during seven flybys over nearly seven years to gradually bring its orbit closer to the Sun. The spacecraft will fly through the Sun’s atmosphere as close as 3.8 million miles to our star’s surface, well within the orbit of Mercury and more than seven times closer than any spacecraft has come before. (Earth’s average distance to the Sun is 93 million miles.)
Flying into the outermost part of the Sun's atmosphere, known as the corona, for the first time, Parker Solar Probe employs a combination of in situ measurements and imaging to revolutionize our understanding of the corona and expand our knowledge of the origin and evolution of the solar wind. It also makes critical contributions to our ability to forecast changes in Earth's space environment that affect life and technology on Earth.
NEAR EARTH SPACE HABITATS
People need food, water, air, clothing, shelter, waste disposal, and some measure of safety
to live. Earth gives us these things, but outer space does not (not even on other planets).
There is no air to breathe in space. Space is either too cold or too hot for humans. Radiation
from the Sun and cosmic rays can harm a person. There are small and large objects—natural
(meteoroids) or artificial (pieces of rockets, paint chips, and other “space junk”)—that travel
fast enough to make holes in metal sheets or spacesuits. A habitat built in space must provide
everything essential for a comfortable life while shielding people from the dangers of space.
There are four kinds of space habitats:
Spaceships (such as the space shuttle)
Space stations that orbit Earth (near-Earth habitats)
Bases and settlements on other worlds (such as the Moon and Mars)
Permanent structures in deep space
Did you know?
A spaceship is for travel; a space station is for living. A spaceship carries a person from one habitat (such as Earth) to another (the space station) and provides a comfortable environment for as long as the trip lasts. A space station, on the other hand, must keep people alive for months or years.
FEATURES OF A NEAR-EARTH HABITAT
Consumables are things that are used up and must continually be replaced. For a near-Earth
space habitat, the consumables—food, clothing, water, and air (to start with)—are brought
up from the ground. A space station keeps air at the same pressure as on the ground. This lets
the occupants live and work in regular clothes rather than wear spacesuits all the time. The
pressurized area also protects occupants from some levels of radiation and tiny meteoroids and space debris.
To protect people from high radiation events, such as solar flares, a small heavily shielded area is usually provided. For people to live in space for long periods, they must have a way to dispose of wastes—solid and liquid body wastes, wastewater from washing and cleaning, water from fuel cells that generate electricity, used food containers, packaging, and other trash. Water can be collected and recycled or discarded into space. Garbage usually is put into a robot craft that burns up in the atmosphere.
Did you know?
On a large space station, water and air can be recycled and some food grown to reduce the amount that must be transported. Chemical “scrubbers” remove carbon
dioxide and return clean air to the habitat. Water is recycled from the moisture collected from the air and from wastewater (including urine).
Heat is another waste product. People and equipment produce heat as they work. If there is no way to get rid of the excess heat, it will build up. Soon it would be too hot for either people or machines to work. This heat is collected from living and working areas and shed into space by radiators. Fuel cells use hydrogen and oxygen to make electricity, also producing water. On the space shuttle, wastewater was dumped overboard, while on the International Space Station, water from fuel cells is saved and used for drinking. Many trips to a space station are necessary to bring enough supplies to keep the occupants alive and well for a long time. This is very expensive. Radiator panels that stick out into space work like the radiator in a car. A liquid passes through the hot area and absorbs heat. The hot fluid flows through the panels, where the heat is given off into space. This process cools the liquid, which is then pumped back to the hotter area to pick up more heat.
The first space station to orbit Earth was named Salyut. The Soviet Union launched seven Salyuts between 1971 and 1982. The earliest Salyut stations were designed only for temporary operations. Crews flew to the stations in Soyuz spacecraft and were resupplied by unmanned Progress vehicles. Salyut 6 (1977–82) and Salyut 7 (1982–86) were designed for longer missions. The longest mission was 237 days. The last crew left Salyut 7 in 1986. The space station re-entered Earth’s atmosphere in 1991, burning up over Argentina.
The United States launched its first space station, Skylab, in 1973 atop a Saturn V rocket, the same type that sent astronauts to the Moon. The third stage of the rocket was converted to provide living quarters, life support, and scientific instruments for a crew of three. Apollo command modules carried astronauts to and from Skylab.
Eleven days after Skylab was launched, three astronauts docked with it. They noticed one of two large solar panels had torn away. A second solar panel was jammed, and part of the heat shield was missing. The crew installed a cover over the unshielded area to cool the spacecraft. They freed the jammed solar panel and restored power to the craft. These unplanned activities showed how people could repair equipment and structures in space. Skylab’s orbit decayed faster than expected because greater than expected activity on the Sun “puffed up” the top of Earth’s atmosphere, slowing the station down. Skylab was destroyed as it burned up in the atmosphere in 1979.
In 1986, the Soviet Union launched the first module of Mir (meaning “peace”), the next generation of space stations. Unlike Salyut, the Mir space station could have modules attached to each other. Eventually, Mir grew to be a set of six modules that totaled 107 feet long and 90 feet wide. Mir was occupied for more than 12 of its 15 years in orbit. It served as a home in space for 104 people representing 11 countries. One of the cosmonauts (Soviet/Russian astronauts), Dr. Valeri Polyakov, spent 438 days in space before returning to Earth. Three other cosmonauts spent at least one year in space.
THE SPACE SHUTTLE
The most ambitious space vehicle to date is certainly the United States’ space shuttle, in service from 1981 to 2011. This system used solid-fuel rocket boosters and a large external tank for liquid fuel in combination with an airplane-like vehicle, the orbiter, to lift up to seven crew members and 25 tons of pay-load into a low Earth orbit and remain there for as long as two weeks. Because the orbiter, which carried the expensive liquid-fuel rocket engines, could be refurbished and flown again repeatedly, the shuttle is regarded as the first reusable space launch system. It was used for launching satellites, repairing them in space, and even returning them to Earth, and served as a kind of temporary space station for performing scientific experiments. Combining all these capabilities into one vehicle, however, proved problematic. Originally conceived as a low-cost, frequent space transportation system accessible to commercial users, the shuttle proved much more expensive to operate than anticipated. Furthermore, in the course of 130 flights, two orbiters—Challenger in 1986 and Columbia in 2003—were destroyed with the loss of all crew members. After the loss of Challenger, the types of payloads flown on the shuttle were restricted, limiting it primarily to purely scientific missions. While the space shuttle was intended to be a method of transportation between the ground and low Earth orbit, it became the only space habitat for astronauts from its first launch until the mid-1990s.
FUN FACTS ABOUT THE SPACE SHUTTLE
In 8 1 / 2 minutes, the space shuttle accelerates at launch from zero to 17,400 miles per hour, almost nine times as fast as a rifle bullet.
If the main engines pumped water instead of fuel, they would drain an average-sized swimming pool in 25 seconds.
The solid rocket boosters consume more than 10 tons of fuel each second at launch.
The orbiter has more than 2 1 / 2 million parts, including 230 miles of wire.
THE NEW ERA OF SPACE TRANSPORTATION
With the retirement of the space shuttle in 2011, the only regular crew transport to the ISS is via the Russian Soyuz crew vehicle. In the United States, a number of companies are working hard to provide the next generation of cargo and crew vehicles. Having multiple launch vehicles available reduces the risk to the space station crew.
The military was concerned about not having the ability to put satellites in orbit after cargo was restricted following the Challenger accident. In the mid-1990s, it decided to work with Boeing and Lockheed Martin to develop a pair of launch vehicles, the Delta IV and Atlas V, respectively, that could lift large assets into space. In the late 1990s, Beal Aerospace tried to build inexpensive vehicles to launch commercial satellites to geostationary orbit, and at one point fired the largest liquid rocket motor developed in the United States since Apollo. Government subsidies to commercial competitors drove the company to close in 2001. Shortly thereafter, SpaceX began development of the Merlin rocket motor and Falcon family of launch vehicles, with the larger Falcon 9 rocket having its first successful delivery of payload to orbit in 2010.
The delivery of crew is more complicated. NASA began working with industry in 2004 to provide alternatives to the shuttle program. Many proposals recommended use of the existing Atlas and Delta rockets. NASA later decided to develop its own launch vehicle that used elements of the space shuttle. This became the Ares rocket component of the Constellation
program to go to Mars by way of the Moon. Funding was cut in 2010, which left private
efforts, already underway, as the only potential near-term solution. The ISS’s robot arm
captures the Dragon spacecraft as it approaches on a resupply mission. SpaceX designed
its rocket to launch the company’s Dragon capsule, which will also have a crewed version.
One design feature of the Dragon capsule is that instead of using “tractor” motors on the
nose of the capsule, as with Apollo and Orion, that drag the capsule away from an emergency
situation, the Dragon instead uses “pusher” motors in the base to push the capsule away from a blossoming crisis. SpaceX launched Dragon in October 2012 on the first commercial resupply mission to the ISS. Boeing and Bigelow Aerospace have teamed up to develop and provide the CST-100 capsule, designed to be launched on Delta, Atlas, and Falcon rockets, for launching astronauts into low Earth orbit.
NASA plans to continue exploring space - sustained human presence on the moon by 2024 and after that, Mars. Read more about it here.
Pre-Camp Mission Highlight!
Did you watch the launch of SpaceX's Crew Dragon as a part of the pre-camp mission? This was the first US launch of astronauts into space since the space shuttle in 2011
INTERNATIONAL SPACE STATION
Learn about the International Space Station (ISS) during lunch or dinner at the Dining Hall!
PLANETARY BASES AND SETTLEMENTS IN SPACE
Where would we build space bases and settlements? The Moon and Mars are current candidates. Bases and settlements could also be built on asteroids, on the moons of other planets, and even in space itself (in orbit). At first, these bases would depend on supplies from Earth, but they could eventually become self-sufficient as we learn how to make use of the materials found in space.
A base is normally supported and supplied by a government, while a settlement would need a financial basis to support itself and its inhabitants. By creating self-sufficient settlements away from Earth, our civilization can spread to other worlds, and even bring life to them. Having a space-based civilization in existence would also make it easier to recover from a widespread disaster on Earth.
FREE SPACE FACILITIES
Not every location of interest in space is on a planetary surface. One example is the Earth-Moon L1 point (EML-1). Balanced in one direction by the gravity of Earth and in the other by centrifugal force and the gravity of the Moon, the L1 point lies about 86 percent of the way to the Moon on an imaginary line connecting the centers of Earth and the Moon. A facility in a halo orbit around EML-1 (like the SOHO and Genesis probes at the Sun-Earth L1 point) would benefit from a number of advantages:
It is accessible from any inclination of low Earth orbit, even from the ISS.
It has access to any point on the lunar surface.
It offers a “high-ground” view of space traffic out to geostationary orbit.
It is the cheapest place, fuel-wise, to launch a mission to an asteroid or to Mars.
Probes can be sent out on the interplanetary superhighways and brought back periodically to be serviced and upgraded like the Hubble Space Telescope.
Another location of interest is the Earth-Moon L5 point, trailing 60 degrees behind the Moon in its orbit. This was the location proposed by Dr. Gerard O’Neill for large orbital colonies that would provide homes for thousands of individuals in a climate-controlled environment. This type of free space facility requires much more space development; we will need to perfect methods of economically bringing many hundreds of thousands of tons of materials from one space location or object to another before we can build large space colonies. A facility at EML-1 offers the possibility of considering materials from multiple sources. The core modules might be ISS-style or Bigelow inflatable modules, but radiation shielding might be provided by slag from industrial processes on the Moon. There might be an industrial facility there manufacturing solar cells from asteroid materials to be used for solar-power satellites in geostationary orbit or as a garage for nonfunctioning satellites retrieved from geostationary orbit.
A natural extension of using asteroids for the natural resources they contain is to create facilities on or in the asteroids. Such a facility located in the asteroid belt would have access to virtually unlimited resources. Locating a facility within an asteroid would allow for great variability in design of interior spaces, and thick layers of rock would mitigate the dangers from cosmic rays and solar flares, as would be the case in lunar lava tubes. In addition, engines could be mounted on the asteroid, allowing it to be directed to destinations of interest in the solar system. Selection of a particular asteroid would depend on its composition. It is one thing to mine platinum group metals from a large rock; it is another to have the supplies necessary for life, mainly carbon, hydrogen, oxygen, and nitrogen, as well as ample amounts of water. Consequently, any likely target will be extensively examined by robotic probes to determine the resources it would offer for a facility. Visiting an asteroid would be just the first step.
The Moon is just a few days of travel from Earth. Earth-Moon communication takes only a few seconds round-trip. We have had experience with crewed operations on the Moon. The gravity is only one-sixth of Earth’s, so landing on and lifting off from the Moon’s surface does not take much fuel. All of these are advantages.
There are also disadvantages of establishing a lunar base. The Moon does not have an atmosphere. On its surface, people would be unprotected from space radiation and the impacts of micrometeorites. The Moon rotates about once a month, creating a scorching hot day ( 250 degrees F) that lasts two weeks, followed by an intensely cold night (-250 degrees F) that also lasts two weeks. No one knows how the low gravity might affect the growth of children or the aging process if families lived at the base. There are unlikely to be any concentrated bodies of mineral ore to mine. For these reasons, while Moon is not the best place to start a colony, it is suitable for scientific research.
PURPOSES OF A MOON BASE
A moon base would allow continued exploration of the Moon. We can search for valuable materials, such as titanium, helium-3, and rare earth elements. Bases near the north or south poles would receive sunlight almost all the time to power a base. Explorers working out of those bases might find polar ice deposits in nearby areas that are always in darkness. We also might set up an astronomical observatory. A telescope on the Moon’s stable surface, looking out through no air, would have a superb view of the universe. A base on the far side of the Moon would be valuable for radio astronomy, because it would be shielded from almost all the radio “noise” generated on Earth and in space by human activity. Businesses might be able to mine lunar material for a profit. Common metals like iron, aluminum, and titanium could be smelted from moon rocks to make building materials and solar cells. Oxygen, taken out of the rocks, would provide breathable air and rocket propellant. Someday a lunar hotel or resort could be built, followed by a lunar colony.
LIVING ON THE MOON
A moon base would have modules for laboratories and living quarters. The modules would be buried in lunar soil, except for their entrances, to shield the inhabitants from space radiation and solar flares. The lunar soil would also insulate the base from extreme temperatures.
The modules would have the same life-support functions as a space station, providing a breathable atmosphere, clean water, food, power, and temperature control. Water would be recycled as much as possible. Most food would be imported from Earth but could eventually be supplemented by a greenhouse module. A crew would either stay at the base or visit regularly to maintain and repair equipment and do scientific work. At first, all of the modules would be built on Earth and hauled to the Moon. Because this will be expensive, a moon base will grow faster if lunar materials are used to build the modules. Once we develop the technology and capability to mine, process, and transport lunar ore, a settlement on the Moon will be highly desirable.
Mars has many advantages for a base or settlement. Its atmosphere (almost all carbon dioxide) would protect anyone on the surface from micrometeorites and partly from space radiation. The atmosphere is thick enough to produce wind and clouds, and maybe support an airplane. However, the air lacks oxygen and enough air pressure for a person to survive. Any surface water would boil away very fast. Anyone exploring Mars will need to wear a spacesuit, just like on the Moon. What looks like a raging dust storm would make it difficult to see afar.
The gravity on Mars is about 38 percent as strong as Earth’s, so humans and animals might be able to grow and reproduce there normally. A day on Mars is only slightly longer than on Earth, so a person could easily adapt to a Martian day. Mars has huge quantities of subsurface ice in many places, and on the surface in the polar areas. There may be salt water under the ice, which could be tapped by drilling. Elements, such as sodium and chlorine, dissolved in the salty water could be separated and used. Mars rocks would also contain useful metals. In fact, most of the materials needed to build a base or colony probably exist on Mars, but they must be found. Rocket propellants can be made using the carbon dioxide atmosphere and water on Mars, greatly reducing the cost of missions to Mars and Mars settlements.
But Mars has its disadvantages, too. The planet lacks a notable magnetosphere, which helps protect Earth from solar wind particles. Additionally, Mars is much farther away than the Moon. With current technology, it would take five to six months for a crew to reach Mars’ orbit from Earth. With better technology, using nuclear-powered ion rockets, the crew’s trip might be cut to two months. Cargo-only vehicles could be sent as “slow boats” to use less energy, taking as long as a year to reach Mars. Any crew that takes a trip to Mars using a traditional transfer orbit would likely have to stay there for about two years.
BUILDING A MARS BASE
Before starting to build a base on Mars, we will need to send robot rovers to locate
several promising sites. Then humans will survey those sites to find the best location. An
orbiting base would be established in a low Mars orbit, complete with a propellant depot
and a crew habitat. Vehicles to carry crew and cargo to the surface base site would be sent
from Earth to the orbiting base. To make supporting the base more affordable, these vehicles
could be reusable, just like airplanes.
What would be a good place for a base? A location near the equator for warmth, if possible. We would also want a site with access to ice or water, and that might be closer to the poles. Resources available from the rocks nearby would be important. If we could use the water on Mars, by digging ice out of the ground, we would not need to bring it from Earth, making it much cheaper to build and maintain a base. A low-lying location would provide the best protection from space radiation. However, just as on the Moon, all permanent habitats would be buried underground, to reduce radiation exposure. Temporary habitats could be on the surface, but they would have to withstand the raging dust storms on Mars. All habitat modules would be insulated against the cold. Methods would need to be perfected to get rid of Mars dust on space-suited explorers entering the habitats.
Just like on the Moon, the first components to build the base would come from Earth. Bulldozers and backhoes could be used to dig holes and bury the habitat modules. To dig for water or to look for life, heavy drilling equipment would be designed to operate under Mars conditions. All habitat modules would be insulated against the cold.
The base would need energy for heat and to run its equipment. Some power could come from solar panels during the day, but a small nuclear reactor would be ideal for power around the clock. Electricity from the reactor could be used to turn carbon dioxide (from the air) and water or ice (from the crust) into oxygen, hydrogen, and other materials. The oxygen could be used directly to make breathable air. It might also be possible to ship a small smelter and manufacturing plant to Mars, for turning local materials into metal and parts for new habitat modules. The water found there might make it possible to use other kinds of construction materials, such as locally produced concrete.
LIVING ON MARS
The oxygen and hydrogen from Mars’ water could be used as rocket propellants for flights back into Mars orbit and to power “over-the-road” vehicles. Vehicles for traveling on the surface of Mars could include rovers large enough for several people, and buggies that space-suited crew members could ride. The crew would stay busy maintaining the base, conducting research, and prospecting for better supplies of water and minerals. They would explore and learn about the topography, geology, and weather of Mars. Recent proof that methane is being produced underground on Mars means that either bacteria or geologic activity is producing it. A major focus of the base may be drilling to find life. Food for the crew would come from Earth at first. But eventually food could be grown locally. Mars has enough sunlight for plants to grow in pressurized greenhouses, but keeping them warm would take much energy. By the time we are ready to go to Mars, we may know how to make some food synthetically, without using plants at all.
Did you know?
Because Mars is far from the Sun, it does not get hot. However, it can get cold enough in winter for dry ice to form directly on the polar caps from the carbon dioxide in the atmosphere.
THE FUTURE OF SPACE EXPLORATION AND SPACE DEVELOPMENT
Because the Space Age is just over 60 years old, we assume that the history of humankind’s adventures in and use of space is only just beginning. There is a lot of future to anticipate! Space activities in the United States and in other countries are undergoing a major transformation. Because the space station is nearly complete, astronauts can turn more of their attention to scientific investigations. Private rocket vehicles are being developed to take both cargo and passengers for short suborbital (up and down) trips and into low Earth orbit. Robotic probes are being launched by countries other than the United States and are now playing a major role in exploring the solar system.
Spacecraft visits to minor planets have mostly been flybys, and have ranged from dedicated missions to incidental flybys and targets of opportunity for spacecraft that have already completed their missions. The first spacecraft to visit an asteroid was Galileo, which flew past 951 Gaspra in October 1991; an incidental encounter while the probe was en route to Jupiter. The first dedicated mission was NEAR Shoemaker, which was launched in February 1996, and entered orbit around 433 Eros in February 2000, having first flown past 253 Mathilde. NEAR was also the first spacecraft to land on an asteroid, surviving what was intended to be an impact with Eros at 20:01 on 12 February 2001 at the planned end of its mission. As a result of its unexpected survival, the spacecraft's mission was extended until 1 March to allow data to be collected from the surface.
NASA is one step closer to landing on another asteroid - Bennu. An ancient relic of our solar system’s early days, Bennu has seen more than 4.5 billion years of history. Scientists think that within 10 million years of our solar system’s formation, Bennu’s present-day composition was already established. Bennu likely broke off from a much larger carbon-rich asteroid about 700 million to 2 billion years ago. It likely formed in the Main Asteroid Belt between Mars and Jupiter, and has drifted much closer to Earth since then. Because its materials are so old, Bennu may contain organic molecules similar to those that could have been involved with the start of life on Earth. Learn more about NASA's goal to touching Bennu.
There is a continuing public debate on what role the U.S. government can and should play in this new era of space exploration. The private decisions by companies and the public ones by governments will determine the future of the space program. While some of these discussions may be technical and complicated, many are practical or about costs and benefits. You can watch the new space program take shape right before your eyes! Here are some of the issues under discussion:
What should the next major goal of the U.S. crewed space program be: Go back to the Moon, go to Mars, visit an asteroid, focus on space development projects such as creating space energy resources for use on Earth, focus on research on the space station, focus on reducing launch costs, conduct more robotic missions, or have multiple goals?
What are the reasons for going to each destination or working on each goal?
Should the government build another crew-carrying vehicle itself, or rely on one or more private vehicles that can be used without requiring much, if any, development cost from the government?
Should we build a “heavy lift vehicle” that can place objects larger than 75 tons in low Earth orbit, or try to rely on smaller rockets and assemble larger vehicles in orbit as was done with the space station?
What is the best way to build reusable space launchers to reduce launch costs?
How much should the U.S. space program rely on cooperation with other countries?
How much money can the government spend on the space program each year?
How much should be spent on robotic exploration, and how much on the crewed program?
What kind of vehicle should be built for crews to operate in deep space away from low Earth orbit?
Space development represents a step beyond space exploration—which is basically finding out what is there—and the use of the resources in space. Many asteroids have large amounts of very valuable platinum group metals in them, which we may mine someday. The Moon has large amounts of oxygen, silicon, aluminum, and titanium in its soil. Away from Earth, even as close as in the orbit used by communications satellites, the Sun shines virtually all the time and is 30 percent stronger than on the ground. This makes it a very good location for solar panels, which would get about five to 10 times more energy per day than they would on Earth. This concept is called space solar power, but the energy is used on Earth.
Space development also means building infrastructure in space for humans to use, just like building roads and power stations on Earth. Part of this involves equipment that would make it easier, cheaper, and safer to move people and cargo from Earth to space and to different locations in space. The space station itself is an example of infrastructure. Other examples include propellant depots to accumulate large quantities of propellants for deep space missions and reusable space tugs to move cargo between orbits instead of using expendable rocket stages.
Exploring space helps us better understand and protect our home planet. As we begin our move into the universe, we look back at our home world and see how small, yet how beautiful, it is. Boundaries of states and nations are invisible. It becomes obvious that Earth itself is a great spaceship on an unending journey and that all of us are astronauts. Space exploration is the greatest adventure of all.
CONTINUE THE MISSION
Explore more about space exploration by touring museums from the comfort of your own home!
HEAD TO THE LAB!
Take the suggested route to The Lab to build your own rocket!
Explore The Lab
YOU ARE HERE
Go back to the campground
Space Exploration Merit Badge Pamphlet, NASA