Category Science

How do NASA and other space agencies communicate with spacecraft?

There are several spacecraft in space. But how do NASA and other space agencies communicate with these spacecraft?

Deep Space Network

Space agencies communicate with spacecraft using the Deep Space Network or DSN. The DSN is a collection of big radio antennas situated in different parts of the world. NASA’S DSN locations are near Canberra, Australia: Madrid, Spain, and Goldstone, California, the US. These sites are almost evenly spaced out meaning even as Earth turns, they never lose contact with the spacecraft.

ISRO, the Indian space agency’s DSN is located at Byalalu, near Bengaluru, Karnataka.

Space agencies use these DSN antennas to send instructions to the spacecraft while the spacecraft send images and other information to these antennas. The antennas also tell us about the location of spacecraft and how they are doing.

Connecting with the DSN antenna

Since spacecraft cannot carry a lot of weight as they need to leave Earth’s orbit and stay in space, all spacecraft are fitted with small antennas that can beam weak radio signals back to Earth. The farther away a spacecraft the larger the DSN antenna required to detect its signal and communicate with it. The largest antennas at each of NASA’S DSN sites is 70 mt in diameter.

Post connecting with an antenna

Once a spacecraft communicates with the DSN antenna, centres at each DSN site receive information. In the case of NASA, these sites send the information to the Space Flight Operations Facility at the Jet Propulsion Laboratory in Pasadena, California. Here, photos and other data are processed and shared with scientists and the rest of the world.

 

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What is the Hayabusa-2 mission?

The six-year-old Ryugu mission came to an end for Japan’s Hayabusa-2 spacecraft when it brought back a capsule of samples from the asteroid on December 6. The capsule landed near Woomera in South Australia. After preliminary inspection, it was flown to the Japan Aerospace Exploration Agency (JAXA) research centre. The extremely high precision required to carry out the mission thrilled many in Japan. The project’s manager, Yuichi Tsuda of JAXA, called the capsule a “treasure box.” What’s the mission Hayabusa-2 all about and what’s special about Ryugu?

The unmanned Hayabusa-2 spacecraft was launched on December 3, 2014 to Ryugu, an asteroid more than 300 million km away from Earth. It is a successor to the Hayabusa mission, which returned asteroid samples from Itokawa in June 2010.

Hayabusa-2 arrived at the Ryugu asteroid in June 2018 after which it deployed two rovers and a small lander onto the surface. The asteroid’s extremely rocky surface forced the mission’s team to revise landing plans, and the spacecraft managed to collect data and soil samples in the more than one-year time it spent by Ryugu. In its first touchdown in February 2019, the spacecraft collected surface dust samples. In June 2019, Hayabusa-2 blasted a crater into the asteroid’s surface and then collected underground samples from the asteroid, a first for space history. In late 2019, Hayabusa-2 left Ryugu on its year-long journey to return the samples to Earth which ended on December 6, 2020.

How did the samples reach Earth?

As it approached Earth, approximately at 220,000 km from space, Hayabusa-2 released a capsule and fired its engines to push off in another direction. The 16 kg capsule entered the Earth’s atmosphere and landed inside the Woomera Range Complex in the South Australian outback using a parachute. A recovery team collected the pan shaped capsule, about 40 cm in diameter. The capsule contains soil samples taken from two different sites on asteroid Ryugu. Some gases might also be embedded in the samples. The preliminary inspection was done at a lab in Australia. The Hayabusa-2 team wanted the sample in Japan within 100 hours of its entry into Earth in order to keep the space rock pristine. So the capsule was taken on a nine-hour flight to the JAXA.

What is special about Ryugu?

Ryugu is a Near-Earth Asteroid (NEA) with orbits that pass dose by the Earth. It is classified as a potentially hazardous asteroid. Ryugu is an ancient fragment of a larger asteroid that formed in the cloud of gas and dust that spawned our solar system. It is an intriguing type of asteroid that’s rich in carbon, an element essential to life. The water composition of some asteroids is believed to be similar to Earth. By studying Ryugu, scientists hope to test this theory.

What can the asteroid samples tell us?

Asteroids orbit the Sun but are much smaller than planets. Scientists believe asteroids are made of the same stuff that went into forming the planets such as Earth They are among the oldest objects in the solar system and therefore may contain dues to how Earth evolved.

Scientists say the samples, especially those taken from under the asteroids surface contain data from 4.6 billion years ago unaffected by space radiation and other environmental factors. They are particularly interested in studying organic materials in the samples to learn about how they are distributed in the solar system and if or how they are related to life on Earth. The samples may help explain the origins of the solar system and how water helped to bring life to Earth. Fragments brought back from Ryugu can also tell its collision and thermal history.

Why is the mission such a big deal for Japan?

The first Hayabusa spaceship’s return was considered a miracle, given the troubles it encountered. JAXA’S subsequent Venus and Mars missions also were flawed. According to the Hayabusa-2 team, it used all the hard lessons learnt from the earlier missions to accomplish a 100 times better than “perfect outcome.

What is next for Hayabusa-2?

About an hour after the sample capsule separated from Hayabusa-2, the spacecraft was sent on another mission to the smaller asteroid. 1998KY26. That is an 11-year journey one way. The mission is to study possible ways to prevent big meteorites from colliding with Earth. Between 2021 and 2026, the spacecraft will also conduct observations of exoplanets.

As for the samples, some will be shared with NASA and other international scientists. About 40% of them will be stored for future research.

 

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Which is the world’s first communication satellite?

How do you feel when you are in on a secret that your friends do not know yet? How do you feel when your parents ask you to keep a secret before the planned big reveal to the extended family? Keeping answers to those questions in mind, imagine how it would be if you are keeping a secret for your country. And add to it the fact that you are among the select few who know the complete truth…

Clarke’s idea

The idea of space satellites for communication was first proposed in 1945 by popular English science fiction writer Arthur C. Clarke. Even though technology wasn’t as advanced, he believed that a group of Earth-orbiting satellites could securely send information to even remote locations. With transatlantic cables and radio signals incapable of achieving that, the need was definitely there. But it wasn’t until the end of the 1950s that his ideas became reality.

The Signal Communication by Orbiting Relay Equipment (SCORE) project was a top-secret mission that went on to become the world’s first successful demonstration of a long-range satellite radio-relay system. It started off as a routine suborbital mission test for the outsiders, before going on to reveal its secrets.

Strict orders for secrecy

Shrouded in secrecy, only 88 people were informed of its existence, with strict orders not to reveal anything to the media, colleagues, or even their own families. The idea was to inform the world if the mission was successful or to keep it a secret forever if it failed.

Apart from the burden of secrecy, there were other challenges too that had to be surmounted. The communication system had to be developed, the payload had to be within a certain weight and ground stations had to be established. On top of these, the SCORE communication package was to be built into the Atlas launch vehicle’s side pods, and not as a discrete spacecraft as was the norm back then. And all of this had to be done within a few months.

By the time SCORE project’s Atlas B was launched on December 18, 1958, the Soviets had already launched three successful Sputnik satellites into orbit. With the pressure on them, the Americans were not only trying to look further from their past failures, but also boost their national image once again.

Safety hazard? Not really!

The observing engineers noticed that the Atlas veered off its course considerably, prompting a safety hazard. This led to a signal to the Range Safety Officer to destroy it, who, however, ignored the message and let the rocket surge forward.

This was because the Range Safety Officer was among the 35 people in the entire world with knowledge of what Project SCORE’s motives were. Among the original 88, 53 were misled to believe the mission was cancelled and that this was simply another missile test. Far from being a routine test, however, it was to send an Atlas intercontinental ballistic missile (ICBM) into low Earth orbit and also launch the world’s first communication satellite.

Only as the rocket veered off its presumed course towards low Earth orbit was its primary objective revealed. While an Atlas ICBM achieved orbit for the first time in history, the second objective proved a little more elusive.

The communications system was designed such that it would not only transmit pre-recorded messages that could be heard by anyone in Earth, but also send and receive messages from the SCORE ground stations. The pre-recorded messages included one from the U.S. President Dwight Eisenhower.

During the first few orbits, the ground station signalled the communication package to broadcast President Eisenhower’s message. But it wasn’t until the 13th orbit, on December 19, that it finally responded as the ground station commanded the back-up system.

Eisenhower’s message

“This is the President of the United States speaking,” the recording said. “Through the marvels of scientific advance, my voice is coming to you from a satellite circling in outer space. My message is a simple one. Through this unique means, I convey to you and to all mankind America’s wish for peace on Earth and goodwill toward men everywhere.”

Despite being developed and launched at almost break-neck speed, Project SCORE ticked off a lot of boxes for the Americans. It was the world’s first communication satellite, even though its batteries died 12 days after launch and it burned up as it reentered the Earth’s atmosphere on January 21, 1959. It was the first successful trial of an Atlas launch vehicle, which would go on to be used for Project Mercury (taking the first Americans to space). It was the heaviest object until then to be launched into orbit and also the first time a missile-guidance system was used to put a satellite into orbit.

As for Eisenhower’s message, it was added to the National Recording Registry (a list of sound recordings that are “culturally, historically or aesthetically important, and/or inform or reflect life in the United States”) by the Library of Congress over 50 years after it was delivered. With that, SCORE’s message has been saved for generations to come.

 

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How can we help to save the plants?

You may think there is not much you can do to help save plants. But there are lots of things you can do. When you go on a hike, stay on the path. Leaving the path harms the plants.

Sometimes you can help plants by not doing things. Do not pick or dig up wild flowers and other plants. Even though some are still plentiful, others are becoming rare. Enjoy wild flowers by taking pictures, or by drawing them. Buy seeds gathered in national parks or from seed companies. Then other people can enjoy the wild flowers, too.

Remind grown-ups to be very careful with campfires or outdoor cooking. Make sure that fires are out completely before you leave the area. If the weather has been very dry, don’t build fires at all. And when you leave camp, take all your rubbish with you to a litter bin.

Don’t break off limbs or peel bark from trees. The outside bark protects a tree from harmful insects and fungus. The inner bark moves food from the leaves to the roots. Peeling off a tree’s bark or breaking off its limbs can kill the tree.

You can help save trees by recycling. Many communities have recycling programmes. This means that used paper is picked up and taken to factories that use it to make new paper. Your family can recycle junk mail, old magazines, boxes, cereal boxes, toilet paper tubes, and even the tags from teabags.   

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How people are working together to protect the world’s plants?

People are working together in many ways to save the world’s plants.

Some people work directly with plants. Growers trade seeds with one another to help a species’ chances to survive. They also grow endangered plants in greenhouses. Then they replant the plants in the wild. Sometimes, people build fences around rare plants in the wild to keep away animals that may eat or trample them.

Many groups work to protect plants. These include the United Nations, the International Union for the Conservation of Nature and Natural Resources (IUCN), and the World Wide Fund for Nature (WWF). They inform governments and people about endangered plants and raise money to help save them.

Many governments have passed laws to protect plants. These laws protect endangered plants and animals from hunting, collecting, and other activities that could harm them or their communities. Many countries also have signed an agreement called CITES. By signing this agreement, they promise not to buy or sell endangered plants or animals, or products made from them.

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What causes fire in forest?

The forest rangers are worried. The weather is hot and there has been no rain for a long time. They know the forest is as dry as dust. It would take only a tiny spark or a lightning strike to turn the whole forest into a roaring, raging sea of fire.

From their watchtower high above the trees, the rangers see a thin spiral of smoke. Fire! There’s a fire in the forest!

A quick call for help goes out. Firefighters rush to the blaze, in trucks. Working quickly, they battle the blaze with streams of water and shovelfuls of soil. They chop down trees and dig up the ground to keep the fire from spreading.

Overhead, aeroplanes swoop over the fire, dropping water and chemicals on it. Other planes bring firefighters called smoke jumpers. They parachute into places that the firefighters on the ground can’t reach.

At last, after many hours or sometimes many days, the fire is out. Thousands of trees have been saved. Thousands of trees have been destroyed.

Picture Credit : Google