# How do you place a satellite in orbit?

With all the media frenzy about Spacex over the days we received a few requests asking us to explain how satellites are launched into orbit.

We shall do so through a thought experiment proposed by Isaac Newton when he was trying to understand how the moon was orbiting the earth.

## Newton’s cannonball

Just imagine standing on top of a really tall mountain with some cannonballs and a cannon.

We will start firing these cannon balls with different speeds by constantly increasing the amount of firepowder that we add and observing the response.

(a) Speed of cannonball < 7300 m/s

(b) Speed of cannonball ~7300 m/s —-> Circular orbit

( c) Speed of cannonball ~8000 m/s —-> Elliptical orbit

(d) Speed of cannonball ~11200 m/s —-> Parabolic trajectory

(e) Speed of cannonball – Crazy

## Gunpowders are not that powerful !

In the real world instead of using gun powder, we use much more sophisticated and powerful
solid rocket fuels which will take the satellite from earth and put it
in orbit.

But once the satellite once put in orbit just keeps falling into orbit.

This applies to the ISS as well: “ISS is always falling; Falling into orbit.

Although this is not by any means a comprehensive post on this topic, but hopefully this gives you a sense of the physics of how satellites are placed in orbit.

Have a good one!

** TRY IT OUT – Newton’s Cannon

India sets new world record, launching 104 satellites at once.

Creating a new world record in the process, India successfully kicked off their 217 launch calendar February 14 by launching a Polar Satellite Launch Vehicle with 104 satellites. The rocket launched at 10:58pm EST from the Satish Dhawan Space Center.

Lofted into a sun-synchronous orbit by the rocket’s fourth stage, 101 cubesats accompanied three larger satellites on the mission. CartoSat-2D is the fourth in a series of high-resolution Earth-imaging satellites domestically designed by India. Less than ten seconds after CartoSat-2D was deployed, the INA-1A and 1B satellites were released. These two satellites are technology demonstrators for a new, smaller satellite bus that India hopes can attract universities and small businesses for space-based payloads.

Of the 101 cubesats deployed, 88 belonged to the Planet company, which – when combined with 100 identical satellites already in polar orbit- will photograph the entire surface of the Earth every day. Eight other cubesats belonged to Spire Global, and will measure atmospheric conditions and global shipping traffic. The remaining five are scientific and communication technology demonstrators

ISRO – the Indian Space Research organization – released a stunning video of the PSLV launch, the first time footage from onboard rocket cameras have been released. Key events in the rocket’s ascent can be seen, including the jettisoning of its six strap-on solid rocket motors, separation of its second and third stages, and jettisoning of the payload fairing.

P/C: ISRO

# The Miura Fold

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The Miura fold is a method of folding a flat surface such as a sheet of paper into a smaller area. The fold is named for its inventor, Japanese astrophysicist Koryo Miura.

## Why it is awesome?

The Miura fold is a form of rigid origami, meaning that the fold can be carried out by a continuous motion in which, at each step, each parallelogram is completely flat.

This property allows it to be used to fold surfaces made of rigid materials; for instance, it has been used to simulate large solar panel arrays for space satellites in the Japanese space program.

The fold can also be unpacked in just one motion by pulling on opposite ends of the folded material, and likewise folded again by pushing the two ends back together.

In the application to solar arrays, this property reduces the number of motors required to unfold this shape, reducing the overall weight and complexity of the mechanism.

## Other cool stuff.

Miura folded maps. Snug it into your pocket when not in need and open it up in style when you are lost !