Ota Lutz is a STEM elementary and secondary education specialist at NASA’s Jet Propulsion Laboratory. When she’s not writing new lessons or teaching, she’s probably cooking something delicious, volunteering in the community, or dreaming about where she will travel next.


This illustration shows the position of NASA's Voyager 1 and Voyager 2 probes, outside of the heliosphere, a protective bubble created by the Sun that extends well past the orbit of Pluto.

In the News

The Voyager 2 spacecraft, launched in 1977, has reached interstellar space, a region beyond the heliosphere – the protective bubble of particles and magnetic fields created by the Sun – where the only other human-made object is its twin, Voyager 1.

The achievement means new opportunities for scientists to study this mysterious region. And for educators, it’s a chance to get students exploring the scale and anatomy of our solar system, plus the engineering and math required for such an epic journey.

How They Did It

Launched just 16 days apart, Voyager 1 and Voyager 2 were designed to take advantage of a rare alignment of the outer planets that only occurs once every 176 years. Their trajectory took them by the outer planets, where they captured never-before-seen images. They were also able to steal a little momentum from Jupiter and Saturn that helped send them on a path toward interstellar space. This “gravity assist” gave the spacecraft a velocity boost without expending any fuel. Though both spacecraft were destined for interstellar space, they followed slightly different trajectories.

Illustration of the trajectories of Voyager 1 and 2

An illustration of the trajectories of Voyager 1 and Voyager 2. Image credit: NASA/JPL-Caltech | + Expand image

Voyager 1 followed a path that enabled it to fly by Jupiter in 1979, discovering the gas giant’s rings. It continued on for a 1980 close encounter with Saturn’s moon Titan before a gravity assist from Saturn hurled it above the plane of the solar system and out toward interstellar space. After Voyager 2 visited Jupiter in 1979 and Saturn in 1981, it continued on to encounter Uranus in 1986, where it obtained another assist. Its last planetary visit before heading out of the solar system was Neptune in 1989, where the gas giant’s gravity sent the probe in a southward direction toward interstellar space. Since the end of its prime mission at Neptune, Voyager 2 has been using its onboard instruments to continue sensing the environment around it, communicating data back to scientists on Earth. It was this data that scientists used to determine Voyager 2 had entered interstellar space.

How We Know

Interstellar space, the region between the stars, is beyond the influence of the solar wind, charged particles emanating from the Sun, and before the influence of the stellar wind of another star. One hint that Voyager 2 was nearing interstellar space came in late August when the Cosmic Ray Subsystem, an instrument that measures cosmic rays coming from the Sun and galactic cosmic rays coming from outside our solar system, measured an increase in galactic cosmic rays hitting the spacecraft. Then on November 5, the instrument detected a sharp decrease in high energy particles from the Sun. That downward trend continued over the following weeks.

The data from the cosmic ray instrument provided strong evidence that Voyager 2 had entered interstellar space because its twin had returned similar data when it crossed the boundary of the heliosheath. But the most compelling evidence came from its Plasma Science Experiment – an instrument that had stopped working on Voyager 1 in 1980. Until recently, the space surrounding Voyager 2 was filled mostly with plasma flowing out from our Sun. This outflow, called the solar wind, creates a bubble, the heliosphere, that envelopes all the planets in our solar system. Voyager 2’s Plasma Science Experiment can detect the speed, density, temperature, pressure and flux of that solar wind. On the same day that the spacecraft’s cosmic ray instrument detected a steep decline in the number of solar energetic particles, the plasma science instrument observed a decline in the speed of the solar wind. Since that date, the plasma instrument has observed no solar wind flow in the environment around Voyager 2, which makes mission scientists confident the probe has entered interstellar space.

graph showing data from the cosmic ray and plasma science instruments on Voyager 2

This animated graph shows data returned from Voyager 2's cosmic ray and plasma science instruments, which provided the evidence that the spacecraft had entered interstellar space. Image credit: NASA/JPL-Caltech/GSFC | + Expand image

Though the spacecraft have left the heliosphere, Voyager 1 and Voyager 2 have not yet left the solar system, and won't be leaving anytime soon. The boundary of the solar system is considered to be beyond the outer edge of the Oort Cloud, a collection of small objects that are still under the influence of the Sun's gravity. The width of the Oort Cloud is not known precisely, but it is estimated to begin at about 1,000 astronomical units from the Sun and extend to about 100,000 AU. (One astronomical unit, or AU, is the distance from the Sun to Earth.) It will take about 300 years for Voyager 2 to reach the inner edge of the Oort Cloud and possibly 30,000 years to fly beyond it. By that time, both Voyager spacecraft will be completely out of the hydrazine fuel used to point them toward Earth (to send and receive data) and their power sources will have decayed beyond their usable lifetime.

Why It’s Important

Since the Voyager spacecraft launched more than 40 years ago, no other NASA missions have encountered as many planets (some of which had never been visited) and continued making science observations from such great distances. Other spacecraft, such as New Horizons and Pioneer 10 and 11, will eventually make it to interstellar space, but we will have no data from them to confirm their arrival or explore the region because their instruments already have or will have shut off by then.

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Interstellar space is a region that’s still mysterious because until 2012, when Voyager 1 arrived there, no spacecraft had visited it. Now, data from Voyager 2 will help add to scientists’ growing understanding of the region. Scientists are hoping to continue using Voyager 2’s plasma science instrument to study the properties of the ionized gases, or plasma, that exist in the interstellar medium by making direct measurements of the plasma density and temperature. This new data may shed more light on the evolution of our solar neighborhood and will most certainly provide a window into the exciting unexplored region of interstellar space, improving our understanding of space and our place in it.

As power wanes on Voyager 2, scientists will have to make tough choices about which instruments to keep turned on. Further complicating the situation is the freezing cold temperature at which the spacecraft is currently operating – perilously close to the freezing point of its hydrazine fuel. But for as long as both Voyager spacecraft are able to maintain power and communication, we will continue to learn about the uncharted territory of interstellar space.

Teach It

Use these standards-aligned lessons and related activities to get students doing math and science with a real-world (and space!) connection.

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TAGS: Teachers, Educators, Science, Engineering, Technology, Solar System, Voyager, Spacecraft, Educator Resources, Lessons, Activities

  • Ota Lutz
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Satellite images of the 2018 Carr and Ferguson wildfires in California

Update – August 8, 2018: This feature, originally published on August 23, 2016, has been updated to include information on 2018 fires and current fire research.

Once again, it’s fire season in the western United States with many citizens finding themselves shrouded in wildfire smoke. Late summer in the west brings heat, low humidity and wind – optimal conditions for fire. These critical conditions have resulted in the Mendocino Complex Fire, the largest fire in California's recorded history. Burning concurrently in California are numerous other wildfires, including the Carr fire, the 12th largest in California history.

Because of their prevalence and effects on a wide population, wildfires will remain a seasonal teachable moment for decades to come. Follow these links to learn about NASA’s fire research and see images of current fires from space. Check out the information and lessons below to help students learn how NASA scientists use technology to monitor and learn about fires and their impacts.


In the News

You didn’t need to check social media, read the newspaper or watch the local news to know that California wildfires were making headlines this summer. Simply looking up at a smoke-filled sky was enough for millions of people in all parts of the state to know there was a fire nearby.

Satellite image of the 2014 King Fire in California

Wildfire Lessons

In these lessons, students play the role of NASA scientist to study the burn area and intensity of wildfires.

Fueled by high temperatures, low humidity, high winds and five years of vegetation-drying drought, more than 4,800 fires have engulfed 275,000-plus acres across California already this year. And the traditional fire season – the time of year when fires are more likely to start, spread and consume resources – has only just begun.

With wildfires starting earlier in the year and continuing to ignite throughout all seasons, fire season is now a year-round affair not just in California, but also around the world. In fact, the U.S. Forest Service found that fire seasons have grown longer in 25 percent of Earth's vegetation-covered areas.

For NASA's Jet Propulsion Laboratory, which is located in Southern California, the fires cropping up near and far are a constant reminder that its efforts to study wildfires around the world from space, the air and on the ground are as important as ever.

JPL uses a suite of Earth satellites and airborne instruments to help better understand fires and aide in fire management and mitigation. By looking at multiple images and types of data from these instruments, scientists compare what a region looked like before, during and after a fire, as well as how long the area takes to recover.

Animation of the FireSat network of satellites capturing wildfires on Earth

This animation shows how FireSat would use a network of satellites around the Earth to detect fires faster than ever before. | + Expand image

While the fire is burning, scientists watch its behavior from an aerial perspective to get a big-picture view of the fire itself and the air pollution it is generating in the form of smoke filled with carbon monoxide and carbon dioxide.

Natasha Stavros, a wildfire expert at JPL, joined Zach Tane with the U.S. Forest Service during a Facebook Live event (viewable below) to discuss some of these technologies and how they're used to understand wildfire behavior and improve wildfire recovery.

Additionally, JPL is working with a startup in San Francisco called Quadra Pi R2E to develop FireSat, a global network of satellites designed to detect wildfires and alert firefighting crews faster. When completed in June 2018, the network's array of more than 200 satellites will use infrared sensors to detect fires around the world much faster than is possible today. Working 24 hours a day, the satellites will be able to automatically detect fires as small as 35 to 50 feet wide within 15 minutes of when they begin. And within three minutes of a fire being detected, the FireSat network will notify emergency responders in the area.

Using these technologies, NASA scientists are gaining a broader understanding of fires and their impacts.

Why It's Important

One of the ways we often hear wildfires classified is by how much area they have burned. Though this is certainly of some importance, of greater significance to fire scientists is the severity of the fire. Wildfires are classified as burning at different levels of severity: low, medium, and high. Severity is a function of intensity, or how hot the fire was, and its spread rate, or the speed at which it travels. A high-severity fire is going to do some real damage. (Severity is measured by the damage left after the fire, but can be estimated during a fire event by calculating spread rate and measuring flame height which indicates intensity.)

Google Earth image showing fire severity
This image, created using data imported into Google Earth, shows the severity of the 2014 King Fire. Green areas are unchanged by the fire; yellow equals low severity; orange equals moderate severity; and red equals high severity. A KMZ file with this data is available in the Fired Up Over Math lesson linked below. Credit: NASA/JPL-Caltech/E. Natasha Stavros.

The impacts of wildfires range from the immediate and tangible to the delayed and less obvious. The potential for loss of life, property and natural areas is one of the first threats that wildfires pose. From a financial standpoint, fires can lead to a downturn in local economies due to loss of tourism and business, high costs related to infrastructure restoration, and impacts to federal and state budgets.

The release of greenhouse gases like carbon dioxide and carbon monoxide is also an important consideration when thinking about the impacts of wildfires. Using NASA satellite data, researchers at the University of California, Berkeley, determined that between 2001 and 2010, California wildfires emitted about 46 million tons of carbon, around five to seven percent of all carbon emitted by the state during that time period.

Animation showing Carbon Dioxide levels rising from the Station Fire in Southern California.
This animation from NASA's Eyes on the Earth visualization program shows carbon monoxide rising (red is the highest concentration) around Southern California as the Station Fire engulfed the area near JPL in 2009. Image credit: NASA/JPL-Caltech

In California and the western United States, longer fire seasons are linked to changes in spring rains, vapor pressure and snowmelt – all of which have been connected to climate change. Wildfires serve as a climate feedback loop, meaning certain effects of wildfires – the release of CO2 and CO – contribute to climate change, thereby enhancing the factors that contribute to longer and stronger fire seasons.

While this may seem like a grim outlook, it’s worth noting that California forests still act as carbon sinks – natural environments that are capable of absorbing carbon dioxide from the atmosphere. In certain parts of the state, each hectare of redwood forest is able to store the annual greenhouse gas output of 500 Americans.

Studying and managing wildfires is important for maintaining resources, protecting people, properties and ecosystems, and reducing air pollution, which is why JPL, NASA and other agencies are continuing their study of these threats and developing technologies to better understand them.

Teach It

Have your students try their hands at solving some of the same fire-science problems that NASA scientists do with these two lessons that get students in grades 3 through 12 using NASA data, algebra and geometry to approximate burn areas, fire-spread rate and fire intensity:

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Lyle Tavernier was a co-author on this feature.

TAGS: teachable moments, wildfires, science

  • Ota Lutz
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In the News

A pair of Earth orbiters designed to keep track of the planet's water resources and evolving water cycle is scheduled to launch this month – no earlier than May 22, 2018. The Gravity Recovery and Climate Experiment Follow-On mission, or GRACE-FO, will pick up where its predecessor, GRACE, left off when it completed its 15-year mission in 2017. By measuring changes in Earth’s gravity, the mission will track water movement around the globe, identifying risks such as droughts and floods and revealing how land ice and sea level are evolving. The GRACE-FO mission is a great way to get students asking, and answering, questions about how we know what we know about some of the major components of Earth’s water cycle: ice sheets, glaciers, sea level, and ground-water resources.

How It Works

animated heat map of co2 concentrations on Earth

Earth Science Lessons

Explore a collection of standards-aligned lessons for grades K-12 all about our home planet.

The GRACE-FO mission, a partnership between NASA and the German Research Centre for Geosciences (GFZ), will measure small variations in Earth’s mass to track how and where water is moving across the planet. This is no easy task, as water can be solid, liquid or gas; it can be in plain sight (as in a lake or glacier); it can be in the atmosphere or hidden underground; and it’s always on the move. But one thing all this water has in common, regardless of what state of matter it is in or where it is located, is mass.

Everything that has mass exerts a gravitational force. It is this gravitational force that GRACE-FO measures to track the whereabouts of water on Earth. Most of Earth's gravitational force, more than 99 percent, does not change from one month to the next because it is exerted by Earth’s solid surface and interior. GRACE-FO is sensitive enough to measure the tiny amount that does change – mostly as a result of the movement of water within the Earth system.

GRACE-FO works by flying two spacecraft in tandem around Earth – one spacecraft trailing the other at a distance of about 137 miles (220 kilometers). By pointing their microwave ranging instruments at each other, the satellites can measure tiny changes in the distance between them – within one micron (the diameter of a blood cell) – caused by changes in Earth’s gravitational field. Scientists can then use those measurements to create a map of Earth’s global gravitational field and calculate local mass variations.

As the forward spacecraft travels over a region that has more or less mass than the surrounding areas, such as a mountain or low valley, the gravitational attraction of that mass will cause the spacecraft to speed up or slow down, slightly increasing or decreasing the relative distance between it and its trailing companion. As a result of this effect, GRACE-FO will be able to track water as it moves into or out of a region, changing the region’s mass and, therefore, its gravity. In fact, the previous GRACE spacecraft measured a weakening gravity field over several years in Central California, enabling an estimate of aquifer depletion, and in Greenland, providing accurate measurements of ice melt over more than 15 years.

Find out more about how the mission works in the video below, from JPL's "Crazy Engineering" video series:

Why It’s Important

Tracking changes in our water resources and the water cycle is important for everyone. The water cycle is one of the fundamental processes on Earth that sustains life and shapes our planet, moving water between Earth's oceans, atmosphere and land. Over thousands of years, we have developed our civilizations around that cycle, placing cities and agriculture near rivers and the sea, building reservoirs and canals to bring water to where it is needed, and drilling wells to pump water from the ground. We depend on this cycle for the water resources that we need, and as those resources change, communities and livelihoods are affected. For example, too much water in an area causes dangerous floods that can destroy property, crops and infrastructure. Too little water causes shortages, which require us to reduce how much water we use. GRACE-FO will provide monthly data that will help us study those precious water resources.

Graphic showing the amount of water in aquifers across Earth as measured by GRACE

A map of groundwater storage trends for Earth's 37 largest aquifers using GRACE data shows depletion and replenishment in millimeters of water per year. Twenty-one aquifers have exceeded sustainability tipping points and are being depleted, and 13 of these are considered significantly distressed, threatening regional water security and resilience. Image credit: NASA/JPL-Caltech

Changes to Earth’s water over multiple years are an important indicator of how Earth is responding in a changing climate. Monitoring changes in ice sheets and glaciers, surface and underground water storage, the amount of water in large lakes and rivers, as well as changes in sea level and ocean currents, provides a global view of how Earth’s water cycle and energy balance are evolving. As our climate changes and our local water resources shift, we need accurate observations and continuous measurements like those from GRACE and GRACE Follow-On to be able to respond and plan.

As a result of the GRACE mission, we have a much more accurate picture of how our global water resources are evolving in both the short and long term. GRACE-FO will continue the legacy of GRACE, yielding up-to-date water and surface mass information and allowing us to identify trends over the coming years.

Teach It

Have students interpret GRACE data for themselves:
Get students learning about global water resources:
Teach students to read, interpret and compare “heat map” representations of Earth science data:

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Try these related resources for students from NASA's Space Place:

TAGS: Earth Science, Teach, In the News, GRACE, Climate Change, Water, Water Cycle

  • Ota Lutz
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In the News

A spacecraft designed to study seismic activity on Mars, or “marsquakes,” is scheduled to lift off on a nearly seven-month journey to the Red Planet on May 5, 2018.

NASA’s InSight Mars lander is designed to get the first in-depth look at the “heart” of Mars: its crust, mantle and core. In other words, it will be the Red Planet’s first thorough checkup since it formed 4.5 billion years ago. The launch, from Vandenberg Air Force Base in Central California, also marks a first: It will be the first time a spacecraft bound for another planet lifts off from the West Coast. It’s a great opportunity to get students excited about the science and math used to launch rockets and explore other planets.

How It Works

Mars

Mars Lessons

Explore our collection of standards-aligned, STEM lessons all about Mars and missions to the Red Planet.

NASA usually launches interplanetary spacecraft from the East Coast, at Cape Canaveral in Florida, to provide them with a momentum boost from Earth’s easterly rotation. It’s similar to how running in the direction you are throwing a ball can provide a momentum boost to the ball. If a spacecraft is launched without that extra earthly boost, the difference must be made up by the rocket engine. Since InSight is a small, lightweight spacecraft, its rocket can easily accommodate getting it into orbit without the help of Earth’s momentum.

Scheduled to launch no earlier than 4:05 a.m. PDT on May 5, InSight will travel aboard an Atlas V 401 launch vehicle on a southerly trajectory over the Pacific Ocean. (Here's how to watch the launch in person or online.) If the weather is bad or there are any mechanical delays, InSight can launch the next day. In fact, InSight can launch any day between May 5 and June 8, a time span known as a launch period, which has multiple launch opportunities during a two-hour launch window each day.

Regardless of the date when InSight launches, its landing on Mars is planned for November 26, 2018, around noon PST. Mission controllers can account for the difference in planetary location between the beginning of the launch window and the end by varying the amount of time InSight spends in what’s called a parking orbit. A parking orbit is a temporary orbit that a spacecraft can enter before moving to its final orbit or trajectory. For InSight, the Atlas V 401 will boost the spacecraft into a parking orbit where it will coast for a while to get into proper position for an engine burn that will send it toward Mars. The parking orbit will last 59 to 66 minutes, depending on the date and time of the launch.

Why It’s Important

Previous missions to Mars have investigated the history of the Red Planet’s surface by examining features like canyons, volcanoes, rocks and soil. However, many important details about the planet's formation can only be found by studying the planet’s interior, far below the surface. And to do that, you need specialized instruments and sensors like those found on InSight.

The InSight mission, designed to operate for one Mars year (approximately two Earth years), will use its suite of instruments to investigate the interior of Mars and uncover how a rocky body forms and becomes a planet. Scientists hope to learn the size of Mars’ core, what it’s made of and whether it’s liquid or solid. InSight will also study the thickness and structure of Mars’ crust, the structure and composition of the mantle and the temperature of the planet’s interior. And a seismometer will determine how often Mars experiences tectonic activity, known as “marsquakes,” and meteorite impacts.

Together, the instruments will measure Mars’ vital signs: its "pulse" (seismology), "temperature" (heat flow), and "reflexes" (wobble). Here’s how they work:

Illustration of the InSight Mars lander on the Red Planet - Labeled

This labeled artist's concept depicts the NASA InSight Mars lander at work studying the interior of Mars.

InSight’s seismometer is called SEIS, or the Seismic Experiment for Interior Structure. By measuring seismic vibrations across Mars, it will provide a glimpse into the planet’s internal activity. The volleyball-size instrument will sit on the Martian surface and wait patiently to sense the seismic waves from marsquakes and meteorite impacts. These measurements can tell scientists about the arrangement of different materials inside Mars and how the rocky planets of the solar system first formed. The seismometer may even be able to tell us if there's liquid water or rising columns of hot magma from active volcanoes underneath the Martian surface.

The Heat Flow and Physical Properties Probe, HP3 for short, burrows down almost 16 feet (five meters) into Mars' surface. That's deeper than any previous spacecraft arms, scoops, drills or probes have gone before. Like studying the heat leaving a car engine, HP3 will measure the heat coming from Mars' interior to reveal how much heat is flowing out and what the source of the heat is. This will help scientists determine whether Mars formed from the same material as Earth and the Moon, and will give them a sneak peek into how the planet evolved.

InSight’s Rotation and Interior Structure Experiment, or RISE, instrument tracks tiny variations in the location of the lander. Even though InSight is stationary on the planet, its position in space will wobble slightly with Mars itself, as the planet spins on its axis. Scientists can use what they learn about the Red Planet’s wobble to determine the size of Mars’ iron-rich core, whether the core is liquid, and which other elements, besides iron, may be present.

When InSight lifts off, along for the ride in the rocket will be two briefcase-size satellites, or CubeSats, known as MarCO, or Mars Cube One. They will take their own path to Mars behind InSight, arriving in time for landing. If all goes as planned, as InSight enters the Martian atmosphere, MarCO will relay data to Earth about entry, descent and landing operations, potentially faster than ever before. InSight will also transmit data to Earth the way previous Mars spacecraft have, by using NASA’s Mars Reconnaissance Orbiter as a relay. MarCO will be the first test of CubeSat technology at another planet, and if successful, it could provide a new way to communicate with spacecraft in the future, providing news of a safe landing – or any potential problems – sooner.

Thanks to the Mars rovers, landers and orbiters that have come before, scientists know that Mars has low levels of geological activity – but a lander like InSight can reveal what might be lurking below the surface. And InSight will give us a chance to discover more not just about the history of Mars, but also of our own planet’s formation.

Teach It

When launching to another planet, we want to take the most efficient route, using the least amount of rocket fuel possible. To take this path, we must launch during a specific window of time, called a launch window. Use this lesson in advanced algebra to estimate the launch window for the InSight lander and future Mars missions.

SEIS will record the times that marsquake surface waves arrive at the lander. Try your hand, just like NASA scientists, using these times, a little bit of algebra and the mathematical constant π to determine the timing and location of a marsquake!

Take students on a journey to Mars with this set of 19 standards-aligned STEM lessons that can be modified to fit various learning environments, including out-of-school time.

Build, test and launch your very own air-powered rocket to celebrate the first West Coast interplanetary spacecraft launch!

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Try these related resources for students from NASA's Space Place:

TAGS: InSight, Lessons, K-12, Activities, Teaching, STEM, Mars

  • Ota Lutz
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A model of Explorer 1 is held by (left to right) JPL Director William Pickering, University of Iowa physicist James Van Allen and Wernher von Braun from the Army Ballistic Missile Agency.

In the News

This month marks the 60th anniversary of the launch of America’s first satellite, Explorer 1. The small, pencil-shaped satellite did more than launch the U.S. into the Space Age. With its collection of instruments, or scientific tools, it turned space into not just a new frontier, but also a place of boundless scientific exploration that could eventually unveil secrets of new worlds – as well as the mysteries of our own planet.

Poster highlighting the main characteristics of Explorer 1 and the Jupiter C rocket.

A poster highlights the main characteristics of Explorer 1 and the Jupiter C rocket that launched it into space. Image credit: NASA

How They Did It

At the height of competition for access to space, the U.S. and the Soviet Union were both building satellites that would ride atop rockets in a quest to orbit Earth. The Soviets launched Sputnik 1 on October 4, 1957. Shortly thereafter, on January 31, 1958, the U.S. launched Explorer 1, the satellite that would begin a new age of scientific space exploration.

Using rockets to do science from orbit was a brand-new option in the late 1950s. Before this time, rockets had only been used for military operations and atmospheric research. Still, rockets of that era weren’t very reliable and none had been powerful enough to place an object into Earth orbit.

Rocket Lessons from NASA/JPL Edu

Rocket Activities

Explore our collection of standards-aligned lessons for grades K-9.

In order to lift Explorer 1 to its destination in Earth orbit, an existing U.S. Army rocket, the Jupiter C, was fitted with a fourth stage, provided by the Jet Propulsion Laboratory in Pasadena, California. For this stage, a rocket motor was integrated into the satellite itself. The new, four-stage rocket was called “Juno 1.”

Prior to these first orbiting observatories, everything we knew about space and Earth came from Earth-based observation platforms – sensors and telescopes – and a few atmospheric sounding rockets. With the success of Explorer 1 and the subsequent development of more powerful rockets, we have been able to send satellites beyond Earth orbit to explore planets, moons, asteroids and even our Sun. With a space-based view of Earth, we are able to gain a global perspective and acquire a wide variety and amount of data at a rapid pace.

Why It’s Important

scientific instruments mounted inside Explorer 1

This photograph shows the scientific instruments mounted inside Explorer 1 alongside its outer case. Image Credit: James A. Van Allen Papers (RG 99.0142), University Archives, The University of Iowa Libraries

Graphic showing the components and science instruments aboard Explorer 1.

This graphic shows the various components and science instruments aboard Explorer 1, including its primary science instrument, a cosmic ray detector. Image credit: NASA/JPL-Caltech

Graphic showing the Van Allen Belts and the locations of Earth-orbiting spacecraft

This graphic shows a cutaway diagram of the Van Allen belts along with the locations of a few Earth-orbiting spacecraft, including the Van Allen Probes. Image credit: NASA

The primary science instrument on Explorer 1 was a cosmic ray detector designed to measure the radiation environment in Earth orbit – in part, to understand what hazards future spacecraft (or space-faring humans) might face. Once in space, this experiment, provided by James Van Allen of the University of Iowa, revealed a much lower cosmic ray count than expected. Van Allen theorized that the instrument might have been saturated by very strong radiation from a belt of charged particles trapped in space by Earth's magnetic field. The existence of the radiation belts was confirmed over the next few months by Explorer 3, Pioneer 3 and Explorer 4. The belts became known as the Van Allen radiation belts in honor of their discoverer.

Although we discovered and learned a bit about the Van Allen belts with the Explorer missions, they remain a source of scientific interest. The radiation belts are two (or more) donut-shaped regions encircling Earth, where high-energy particles, mostly electrons and ions, are trapped by Earth's magnetic field. The belts shrink and swell in size in response to incoming radiation from the Sun. They protect Earth from incoming high-energy particles, but this trapped radiation can affect the performance and reliability of our technologies, such as cellphone communication, and pose a threat to astronauts and spacecraft. It’s not safe to spend a lot of time inside the Van Allen radiation belts.

Most spacecraft are not designed to withstand high levels of particle radiation and wouldn’t last a day in the Van Allen belts. As a result, most spacecraft travel quickly through the belts toward their destinations, and non-essential instruments are turned off for protection during this brief time.

To conquer the challenge of extreme radiation in the belts while continuing the science begun by Explorer 1, NASA launched a pair of radiation-shielded satellites, the Van Allen Probes, in 2012. (The rocket that carried the Van Allen Probes into space was more than twice as tall as the rocket that carried Explorer 1 to orbit!)

The Van Allen Probes carry identical instruments and orbit Earth, following one another in highly elliptical, nearly identical orbits. These orbits bring the probes as close as about 300 miles (500 kilometers) above Earth’s surface, and take them as far out as about 19,420 miles (31,250 kilometers), traveling through diverse areas of the belts. By comparing observations from both spacecraft, scientists can distinguish between events that occur simultaneously throughout the belts, those that happen at only a single point in space, and those that move from one point to another over time.

Watch the video above to learn more about the Van Allen Probes and a discovery they made shortly after starting their mission. Credit: NASA Goddard

The Van Allen Probes carry on the work begun by Explorer 1 and, like all successful space missions, are providing answers as well as provoking more questions. NASA continues to explore Earth and space using spacecraft launched aboard a variety of rockets designed to place these observatories in just the right spots to return data that will answer and inspire questions for years to come.

Teach It

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TAGS: Explorer 1, STEM, NASA in the Classroom, Lessons, Activities, Teachable Moments

  • Ota Lutz
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Update – Sept. 11, 2017: This feature (originally published on April 25, 2017) has been updated to reflect Cassini's current mission status, as well as new lessons and activities.


In the News

After almost 20 years in space, NASA's Cassini spacecraft has begun the final chapter of its remarkable story of exploration. This last phase of the mission has delivered unprecedented views of Saturn and taken Cassini where no spacecraft has been before – all the way between the planet and its rings. On Friday, Sept. 15 Cassini will perform its Grand Finale: a farewell dive into Saturn’s atmosphere to protect the environments of Saturn’s moons, including the potentially habitable Enceladus.

Animation of Cassini Pi in the Sky 4 math problem

Lessons All About Saturn

Explore our collection of standards-aligned lessons about NASA's Cassini mission.

How It Works

On April 22, Cassini flew within 608 miles (979 km) of Saturn’s giant moon Titan, using the moon’s gravity to place the spacecraft on its path for the ring-gap orbits. Without this gravity assist from Titan, the daring, science-rich mission ending would not be possible.

Cassini is almost out of the propellant that fuels its main engine, which is used to make large course adjustments. A course adjustment requires energy. Because the spacecraft does not have enough rocket fuel on board, Cassini engineers have used an external energy source to set the spacecraft on its new trajectory: the gravity of Saturn’s moon Titan. (The engineers have often used Titan to make major shifts in Cassini’s flight plan.)

Titan is a massive moon and thus has a significant amount of gravity. As Cassini comes near Titan, the spacecraft is affected by this gravity – and can use it to its advantage. Often referred to as a “slingshot maneuver,” a gravity assist is a powerful tool, which uses the gravity of another body to speed up, slow down or otherwise alter the orbital path of a spacecraft.

In this installment of the "Crazy Engineering" video series from NASA's Jet Propulsion Laboratory, host Mike Meacham talks to a Cassini engineer about astrodynamics and how it was used to design the Saturn mission's Grand Finale.

When Cassini passed close by Titan on April 22, the moon’s gravity pulled strongly on the spacecraft. The flyby gave Cassini a change in velocity of about 1,800 mph (800 meters per second) that sent the spacecraft into its first of the ring-gap orbits on April 23. On April 26, Cassini made its first of 22 daring plunges between the planet and its mighty rings.

Cassini final orbits petal plot

This graphic illustrates Cassini's trajectory, or flight path, during the final two phases of its mission. The 20 Ring-Grazing Orbits that Cassini made between November and April 2017 are shown in gray; the 22 Grand Finale Orbits are shown in blue. The final partial orbit is colored orange. + Enlarge image

Up-close image of Saturn's clouds from Cassini

Clouds on Saturn take on the appearance of strokes from a cosmic brush thanks to the wavy way that fluids interact in Saturn's atmosphere. This images used in this false-color view were taken with the Cassini spacecraft narrow-angle camera on May 18, 2017. Image credit: NASA-JPL/Caltech/SSI | › Full image and caption

Animated image of Saturn's moon Enceladus from Cassini

This animated image of Saturn's moon Enceladus is a composite of six images taken by the Cassini spacecraft on Aug. 1, 2017. Image credit: NASA-JPL/Caltech/SSI | › Full image and caption

Up-close image of Saturn's rings from Cassini

These are the highest-resolution color images of any part of Saturn's rings, to date, showing a portion of the inner-central part of the planet's B Ring. The view is a mosaic of two images that show a region that lies between 61,300 and 65,600 miles (98,600 and 105,500 kilometers) from Saturn's center. Image credit: NASA-JPL/Caltech/SSI | › Full image and caption

As Kepler’s third law indicates, Cassini traveled faster than ever before during these final smaller orbits. Cassini's orbit continued to cross the orbit of Titan during these ring-gap orbits. And every couple of orbits, Titan passed near enough to give the spacecraft a nudge. One last nudge occured on September 11, placing the spacecraft on its final, half-orbit, impact trajectory toward Saturn.

Because a few hardy microbes from Earth might have survived onboard Cassini all these years, NASA has chosen to safely dispose of the spacecraft in the atmosphere of Saturn to avoid the possibility of Cassini someday colliding with and contaminating moons such as Enceladus and Titan that may hold the potential for life. Cassini will continue to send back science measurements as long as it is able to transmit during its final dive into Saturn.

Why It’s Important

Flying closer than ever before to Saturn and its rings has provided an unprecedented opportunity for science. During these orbits, Cassini’s cameras have captured ultra-close images of the planet’s clouds and the mysterious north polar hexagon, helping us to learn more about Saturn’s atmosphere and turbulent storms.

The cameras have been taking high-resolution images of the rings, and to improve our knowledge of how much material is in the rings, Cassini has also been conducting gravitational measurements. Cassini's particle detectors have sampled icy ring particles being funneled into the atmosphere by Saturn's magnetic field. Data and images from these observations are helping bring us closer to understanding the origins of Saturn’s massive ring system.

Cassini has also been making detailed maps of Saturn's gravity and magnetic fields to reveal how the planet is structured internally, which could help solve the great mystery of just how fast Saturn is rotating.

On its first pass through the unexplored 1,500-mile-wide (2,400-kilometer) space between the rings and the planet, Cassini was oriented so that its high-gain antenna faced forward, shielding the delicate scientific instruments from potential impacts by ring particles. After this first ring crossing informed scientists about the low number of particles at that particular point in the gap, the spacecraft was oriented differently for the next four orbits, providing the science instruments unique observing angles. For ring crossings 6, 7 and 12, the spacecraft was again oriented so that its high-gain antenna faced forward.

Fittingly, Cassini's final moments will be spent doing what it does best, returning data on never-before-observed regions of the Saturnian system. On September 15, just hours before Cassini enters Saturn's atmosphere for its Grand Finale dive, it will collect and transmit its final images back to Earth. During its fateful dive, Cassini will be sending home new data in real time informing us about Saturn’s atmospheric composition. It's our last chance to gather intimate data about Saturn and its rings – until another spacecraft journeys to this distant planet.

Explore the many discoveries made by Cassini and the story of the mission on the Cassini website.

Teach It

Use these standards-aligned lessons to get your students excited about the science we have learned and have yet to learn about the Saturnian system.

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TAGS: Saturn, Titan, Cassini, Grand Finale, Teachable Moments, Kepler's Laws, K-12, Lessons,

  • Ota Lutz
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In the News

This year marks the 40th anniversary of the launch of the world’s farthest and longest-lived spacecraft, NASA’s Voyager 1 and 2. Four decades ago, they embarked on an ambitious mission to explore the giant outer planets, the two outermost of which had never been visited. And since completing their flybys of Jupiter, Saturn, Uranus and Neptune in 1989, they have been journeying toward the farthest reaches of our solar system – where no spacecraft has been before. These two intrepid spacecraft continue to return data to NASA daily, offering a window into the mysterious outer realms of our solar system and beyond.

Illustration of Voyager in space
Teach It!

Try these standards-aligned lessons and activities with students to bring the wonder of the Voyager mission to your classroom or education group.

How They Did It

The Voyager spacecraft were launched during a very short window that took advantage of a unique alignment of the four giant outer planets – one that would not occur again for another 176 years. (Try this lesson in calculating launch windows to get an idea of how it was done.) Launching at this point in time enabled the spacecraft to fly by all four planets in a single journey, returning never-before-seen, close-up images and scientific data from Jupiter, Saturn, Uranus and Neptune that greatly contributed to our current understanding of these planets and the solar system.

Voyager Golden Record
Mission planners knew Voyager would be a historic mission to parts of the solar system never visited by a human-made object. To commemorate the journey, NASA endowed each spacecraft with a time capsule of sorts called the Golden Record intended to communicate the story of our world to extraterrestrials. Both Voyagers carry the 12-inch, gold-plated copper phonograph record containing sounds and images selected to portray the diversity of life and culture on Earth. Find out more about the Golden Record on the Voyager website. Credit: NASA/JPL-Caltech

Why It’s Important

diagram of solar system components

These images of Jupiter, Saturn, Uranus and Neptune (clockwise from top) were taken by Voyager 1 and 2 as the spacecraft journeyed through the solar system. See a gallery of images that Voyager took on the Voyager website. Credit: NASA/JPL-Caltech

In addition to shaping our understanding of the outer planets, the Voyager spacecraft are helping us learn more about the space beyond the planets – the outer region of our solar system. After completing their “grand tour” of the outer planets, the Voyagers continued on an extended mission to the outer solar system. They are now more than 10 billion miles from Earth, exploring the boundary region between our planetary system and what’s called interstellar space.

The beginning of interstellar space is where the constant flow of material from the Sun and its magnetic field stop influencing the surroundings. Most of the Sun’s influence is contained within the heliosphere, a bubble created by the Sun and limited by forces in interstellar space. (Note that the heliosphere doesn’t actually look like a sphere when it travels through space; it’s more of a blunt sphere with a tail.) The outer edge of the heliosphere, before interstellar space, is a boundary region called the heliopause. The heliopause is the outermost boundary of the solar wind, a stream of electrically charged atoms, composed primarily of ionized hydrogen, that stream outward from the Sun. Our planetary system lies inside the bubble of the heliosphere, bordered by the heliopause and surrounded by interstellar space.

solar system components visualized in a kitchen sink
Any flat-bottom sink can provide a visual analogy of these solar system components. In this video, the water traveling radially away from where the faucet stream impacts the sink represents the solar wind. The termination shock is the point at which the speed of the solar wind (water) drops abruptly as it begins to be influenced by interstellar wind. The outer edge of the thick ring of water at the bottom of the sink represents the heliopause. Just like the water in the sink, the solar wind at the heliopause changes direction and flows back into the heliosphere. Credit: NASA/JPL-Caltech.

Though we’ve learned a lot about the heliopause thanks to the Voyager spacecraft, its thickness and variation are still key unanswered questions in space physics. As the Voyagers continue their journey, scientists hope to learn more about the location and properties of the heliopause.

From their unique vantage points – Voyager 1 in the northern hemisphere and Voyager 2 in the southern hemisphere – the spacecraft have already detected differences and asymmetries in the solar wind termination shock, where the wind abruptly slows as it approaches the heliopause. For example, Voyager 2 crossed the termination shock at a distance of about 83.7 AU in the southern hemisphere. (One AU, or astronomical unit, is equal to 150 kilometers (93 million miles), the distance between Earth and the Sun.) That’s about 10 AU closer to the Sun than where Voyager 1 crossed the shock in the north. As shown in this diagram, Voyager 1 traveled through the compressed “nose” of the termination shock and Voyager 2 is expected to travel through the flank of the termination shock.

With four remaining powered instruments on Voyager 1 and five remaining powered instruments on Voyager 2, the two spacecraft continue to collect science data comparing their two distinct locations at the far reaches of the solar system.

diagram of solar system components

In August 2012, Voyager 1 detected a dramatic increase in galactic cosmic rays (as shown in this animated chart). The increase, which has continued to the current peak, was associated with the spacecraft's crossing into interstellar space. Credit: NASA/JPL-Caltech

Since it launched from Earth in 1977, Voyager 1 has been using an instrument to measure high-energy, dangerous particles traveling through space called galactic cosmic rays. While studying the interaction between the bubble of the heliosphere and interstellar space, Voyager 1 revealed that the heliosphere is functioning as a radiation shield, protecting our planetary system from most of these galactic cosmic rays. So in August 2012, when Voyager 1 detected a dramatic increase in the rays, which has continued to the current peak, it was associated with the spacecraft’s crossing into interstellar space.

Meanwhile, Voyager 2 ­­– which is still in the heliosheath, the outermost layer of the heliosphere between the shock and the heliopause ­– is using its solar wind instrument to measure the directional change of solar wind particles there. Within the next few years, Voyager 2 is also expected to cross into interstellar space, providing us with even more detailed data about this mysterious region.

In another 10 years, we expect one or both Voyagers to cruise outward into a more pristine region of interstellar space, returning data to inform our hypotheses about the concentration of galactic particles and the characteristics of interstellar wind.

Even with 40 years of space flight behind them, the Voyagers are expected to continue returning valuable data until about 2025. Communications will be maintained until the spacecraft’s nuclear power sources can no longer supply enough electrical energy to power critical functions. Until then, there’s still much to learn about the boundary of our heliosphere and what lies beyond in the space between the stars.

Teach It

Use these standards-aligned lessons and related activities to get students doing math and science with a real-world (and space!) connection.

  • Hear Here - Students use the mathematical constant pi and information about the current location of Voyager 1 to learn about the faint data-filled signal being returned to Earth.
  • Solar System Bead Activity – Students calculate and construct a scale model of solar system distances using beads and string.
  • Catching a Whisper from Space – Students kinesthetically model the mathematics of how NASA communicates with spacecraft.

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TAGS: Voyager, Farthest, Golden Record, STEM, Teachable Moments, Science, Engineering, Solar System, Interstellar Space, Heliopause, Heliosphere, Heliosheath, Termination Shock, Stars, Heliophysics

  • Ota Lutz
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Adopt the Planet campaign from NASA Earth

In the News

Earth Day, the day set aside each year to celebrate our planet and bring attention to the natural world, is on April 22, 2017. More than one billion people are expected to participate in Earth Day events around the globe that will draw attention to what we know about Earth, how it is changing and how we can be kind to our home planet.

One of the ways that NASA participates – not just on Earth Day, but also year-round – is by collecting and analyzing science data from sensors on Earth and satellites. These data allow us to monitor the health of our planet and better understand how and why it is changing.

Visualizing global data trends – Earth Science – NASA/JPL Education

Earth Day Resources for Educators

Explore our collection of standards-aligned Earth science lessons – plus this new lesson about reading NASA data visualizations and heat maps.

› Explore Earth science lessons from NASA!

This year, to highlight the importance of these data, NASA is inviting people to “adopt” a portion of Earth’s surface and obtain a snapshot of some of the satellite data available for their adopted location. Even though you’ll have no legal or ownership rights to this region, it will be fun to learn about the various types of data available for different locations on Earth. Find out how you can participate.

How It Works

NASA’s fleet of Earth-observing satellites and airborne sensors provides us with data about such vital information as carbon dioxide, carbon monoxide, global land and sea temperature, ice, sea surface salinity, and chlorophyll – just to name a few. The satellites and sensors collect these data over time and from as many perspectives as possible, allowing us to discern trends in the data.

Learn about the fleet of NASA satellites and instruments studying Earth. › Watch NASA's Earth Minute series

A snapshot of data is just one piece of a much larger puzzle because it only gives us an indication of what was happening at the exact moment that data was captured. Even data collected over a year has its limitations because local conditions may ebb and flow over longer time periods. Collecting data about multiple elements of the Earth system over decades or centuries enables us to develop correlation and causation models, powerful indicators of why trends are developing as they are. And using multiple platforms (satellite, aerial, Earth-based) to measure data enables us to validate our data sets.

Why It’s Important

Humans are dependent on a healthy and functioning Earth to survive, which means we need to keep a close eye on all Earth systems and our impacts on those systems. This process of collecting data over time from multiple perspectives, discerning trends and validating the data is crucial to understanding our planet and helping policymakers formulate actions we can take to preserve Earth for future generations.

Earth is a complex, dynamic system we do not fully understand. To learn more about it, NASA, as the agency with access to space, was tasked with launching the first weather satellite back in 1960. Today, NASA uses satellites, aircraft and even an occasional boat to study our planet's air, land and water. It's called "Earth System Science" and we are trying to answer some big questions: How is the global Earth system changing? What causes these changes? How will Earth change in the future? And what we learn benefits society through applications such as weather forecasting, freshwater availability and disaster response. › Watch NASA's Earth Minute series

Teach It

First, introduce students to the kinds of data scientists use to study Earth. Participate in NASA’s Adopt the Planet campaign to receive a snapshot of Earth science data for one patch of Earth. Then encourage students to dig deeper with these standards-aligned lessons:

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TAGS: Earth Day, Climate Change, Earth Science, Lessons, Activities, K-12, Teaching

  • Ota Lutz
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A computer works with an engineer at JPL.

In The News

This week, we celebrate the 80th anniversary of the Jet Propulsion Laboratory. JPL was founded long before it became NASA’s premier center for robotic exploration of the solar system – and even before the agency existed. In fact, JPL started as the test-bed for some of the earliest rocketry experiments (thus the name “Jet Propulsion Laboratory”). There were a number of factors that conspired to change JPL’s focus from rocketry to space exploration. The Space Race and the resulting formation of NASA were two major factors. But also, with its growing expertise in launching rockets to new heights, JPL was anxious to take its experiments even farther. So in 1957, when the Soviet Union won the first leg of the Space Race by placing Sputnik, the first artificial satellite, into Earth orbit, JPL was called into action. A few months later, NASA launched the JPL-built Explorer 1, which became the first U.S. satellite.

Pickering, Van Allen and Von Braun hold a model of Explorer 1 at a post-flight press conference.
Explorer 1 became the first U.S. space satellite in 1958. It was built at NASA's Jet Propulsion Laboratory in Pasadena, California. Image credit: NASA/JPL-Caltech

Soon, the challenge was to land on the moon – and JPL was once again called to the task. Landing on another planetary body had never been accomplished so, understandably, it took a few tries to get things right. JPL’s first attempts at a moon landing with Rangers 1 through 6 all failed for various reasons. Some of the spacecraft flew very near the moon only to miss it by a few hundred kilometers; others met their mark only to have onboard cameras fail. Ranger 7 was the first mission to successfully land on the moon and transmit data, capturing images 1,000-times better than those obtained by ground-based telescopes. It wasn’t a particularly soft landing; rather it was a purposeful crash landing, capturing images along the way. But everyone at JPL was thrilled to have hit their target and returned usable data. These data, and those collected by subsequent missions, made possible NASA’s later human missions to the moon.

Ranger 7 photo of the moon
Ranger 7 was the first U.S. mission to successfully impact the moon. This was one of more than 4,300 images sent back during the flyby. Image credit: NASA/JPL-Caltech

At the same time it was launching the Ranger lunar missions, JPL had also set its sights on venturing even farther into space and began launching a series of missions called Mariner to Venus, Mercury and Mars. It wasn’t long before JPL’s specialty became creating robotic spacecraft to go not just to the moon, but also where no one had gone before.

Learn more about the history of JPL and the U.S. space program in the video series below. And explore the interactive timeline.

How They Did It

What’s often not known is that all the early rocket experiments and later missions to the moon and beyond wouldn’t have been possible without a team at JPL known as the human “computers.” Most of these human computers were women who either had degrees in mathematics or were simply very good at mathematics. Over the course of time, these women not only performed hundreds of thousands of mathematical calculations crucial to the U.S. space program, but also eventually became some of the first computer programmers at NASA.

human computers at JPL
A talented team of women, who were around since JPL's beginnings in 1936 and who were known as computers, were responsible for the number-crunching of launch windows, trajectories, fuel consumption and other details that helped make the U.S. space program a success. Image credit: NASA/JPL-Caltech

In the early days of space exploration, the best mechanical computers were large (the size of a room) and not particularly powerful. Human capabilities were much more powerful for many tasks, including the rapid calculations needed for trajectory analysis and verification, as well as the graphing of data points on trajectories, which made a spacecraft’s path easy to see.

One of the human computers’ main tasks was computing the planned trajectories, or paths, for a spacecraft based on the vehicle weight, lift capacity of the rocket, and the orbital dynamics of the planets.

When a spacecraft is launched, it begins sending telemetry signals back to Earth. These signals tell engineers information about the spacecraft’s location and health. But this information isn’t perfectly straightforward. It arrives as a bunch of numbers that need to be combined in formulas along with other constantly changing parameters (such as velocity, vehicle mass and the effect of gravity from nearby bodies) in order to reveal the spacecraft’s actual location. Before there were computers (as we know them today) to do these calculations, human computers would feverishly calculate the exact location of the spacecraft as the telemetry came in and compare that to the planned trajectories. Their calculations would reveal whether the spacecraft was on target.

a computer tracks a spacecraft's position as it makes its way toward Venus
A computer in the control room at JPL tracks the position of Mariner 2. The spacecraft became the first to fly by another planet when it reached Venus in 1962. Image credit: NASA/JPL-Caltech

Doing the calculations required to get Explorer 1 into orbit was no small task. Calculating the trajectory for a Ranger crash landing or a Surveyor soft landing on the moon was even more challenging. Once humans were destined to be on board for the Apollo missions, the stakes were even higher. Fortunately, JPL had set the stage developing the techniques – and calculations – necessary to land a robotic spacecraft safely on the moon.

Why It’s Important

JPL's human computers
JPL's human computers didn't just help launch the U.S. space program; they also represented an important step forward for women and other underrepresented people at a time when much of the professional world and especially technical fields were dominated by white men. Janez Lawson (seen in this photo from 1953, front row, fifth from the left), was the first African American hired into a technical position at JPL. Having graduated from UCLA with a bachelor's degree in chemical engineering, she later went on to have a successful career as a chemical engineer. Image credit: NASA/JPL-Caltech

Today, JPL continues setting the pace for exploration of the solar system using robots to go where humans hope to venture one day, such as Mars. Though trajectory computations are now done using modern day computers, humans are still required to do trajectory analysis and mission planning. Every mission is different, and with new techniques comes new simulation equations that must be developed and computations that must be performed during actual mission events to ensure success. But even now, nothing is fail-proof. Lots of variables can and do influence spaceflight. Arriving safely on another planet millions of miles away isn’t easy or taken for granted, but when things go right and we achieve a safe landing, it is definitely cause for celebration.

Teach It

When launching to another planet, we want to take the most efficient route, using the least amount of rocket fuel possible. The early human computers quickly discovered that launching when two planets are closest and using a lot of rocket fuel for the job isn’t the best plan.

Use this fascinating bit of history as a real world, advanced algebra and physics lesson with students in this standards-aligned activity that has grades 9-12 calculate the next launch window to Mars!

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TAGS: JPL Anniversary, History, Human Computers, Launch Windows, Algebra, High School

  • Ota Lutz
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