Rocket: I want to fly...higher!

China Space Day Special

The Road to Flying

It's bound to be bumpy

February 15, 1996

Long March 3B carrier rocket

The first expedition under great anticipation

However, the rocket took off in less than 2 seconds.

But suddenly deviated from the launch direction

(The Long March 3B rocket was launched for the first time, and the rocket body showed abnormal posture. Image source: Internet Archive)

▼

In just 22 seconds,

The rocket head dropped and crashed into the hillside

Finally, in the blaze of fire

Shattered to pieces, reduced to ashes

This is a Chinese launch vehicle.

The 9th launch failed

(The Long March 3B failed in its first launch and crashed on a hillside 1.85 kilometers away from the launch site. Image source: Internet Archive)

▼

More than 20 years later

April 9, 2020

The Long March 3B has been successfully launched 26 times in a row

The rocket fell and disintegrated due to abnormal operation of the third stage

This is a Chinese launch vehicle.

22nd launch failure

As of now

History of Chinese Spaceflight

There were 22 launch failures in total.

But at the same time

The number of successful launches reached

334 times

(Please watch in horizontal mode, the first flight of the Long March 7, this is the 222nd successful launch of China's "Long March" series of carrier rockets; in addition: the above text only regards the spacecraft reaching the target orbit as a success, photographer @勾炳宸)

▼

Yes

Failure is painful

But the pinnacle of science

But always gritting my teeth and holding back my tears

To be able to climb

(The following is quoted from Qian Xuesen, the "Father of Chinese Spaceflight")

▼

The correct results come from a large number of mistakes.

That’s why

50 years ago

my country successfully launched its first artificial satellite

Only a "tiny" 0.178 tons

50 years later

Generations of Chinese launch vehicles

Carrying

Beidou, Fengyun, Gaofen, Queqiao, Jianbing

Practice, sky, beacon fire, ocean, magical power

Detection, outpost, resources, Xinnuo, Tianlian

Zhongxing, Tiantuo, Tianhui, Luojia, Yunhai

Carrying

Shenzhou, Tianzhou, Chang'e, Tiangong

Breaking away from gravity again and again

Towards the sea of ​​stars

(Please watch in horizontal mode, the main models of China's "Long March" series of launch vehicles, map by @陈随/Planetary Research Institute)

▼

What kind of upgrade path is this?

What will the future hold?

01

The birth of the small rocket

January 30, 1970

my country's first medium- and long-range ballistic missile

DF-4

Successful test flight

It uses combustion to produce

Jet stream provides thrust

The propellant is

The combination of “fuel + oxidizer”

Can completely get rid of the dependence of combustion on oxygen

Even in the oxygen-free environment of space

Also free to fly

Its arrow body

From bottom to top, it is divided into two levels

After the first stage is completed, it will be separated at high altitude

The second stage will then reignite and take over.

This is

The prototype of China's launch vehicle

(The first stage rocket body is separated. The white track on the right is the first stage rocket body that separated and fell. This is the launch of China's private rocket Hyperbola-1, for illustration. Photographer @余明)

▼

However

To fly around the earth

Satellite's flight altitude

Generally not less than 180 kilometers

The corresponding orbital velocity also needs to be close to 7.9 km/s

Otherwise, under the influence of the earth's gravity and atmospheric resistance,

Falling into the atmosphere

(The 7.9 km/s in the above text is the first cosmic velocity, drawn by @陈思琪&陈随/Planetary Research Institute)

▼

Unfortunately

Such speed and altitude

The Dongfeng-4 is far behind

So the engineers

Continue to upgrade the original rocket body

Upgrade it to a three-stage rocket

Missile warhead on top of the rocket body

Replaced by satellite

Protected by a fairing

Avoid being washed by high-speed airflow

(The rocket fairing is connected with explosive bolts. The bolts can be detonated to unlock, separate and discard the fairing; the picture below is the Long March 7 fairing for illustration, photographer @王若维)

▼

Between the first and second levels

Connected by metal rods

The connection is like being hollowed out

So that when the second stage engine ignites

The jet flame can be discharged as quickly as possible through this

(The "hollow" structure between the two stages is the diagonal metal rod; the picture below shows the appearance of the Long March 4C for illustration, and the foam insulation layer is peeling off. Photographer @韩超)

▼

After a series of optimization

The Dongfeng-4 missile has undergone a transformation

China's first carrier rocket

Long March 1 (CZ-1)

Born

(Schematic diagram of the Long March 1 rocket structure, drawn by @陈随/Planetary Research Institute)

▼

It is 2.25 meters in diameter and about 30 meters high.

Can not exceed

0.3 tons

Load

Delivered to a low Earth orbit at an altitude of about 440 kilometers

For example, China's first artificial satellite

Dongfanghong No.1

Since then

China became the first country after the Soviet Union, the United States, France and Japan

The fifth country to independently launch an artificial satellite

The era of low-Earth satellites in China's space program

This opens

(Dongfanghong-1, photographer @Brücke-Osteuropa)

▼

However

0.3 ton load

It is far from meeting the needs of general satellites.

The launch vehicle is bound to be upgraded again

On propellant

People switch to new

“Fuel + Oxidant” Combination

"Uniform dimethylhydrazine + nitrogen tetroxide"

They are all liquid at room temperature

Not only has higher propulsion efficiency

Once they meet, they will burn immediately

Simple ignition and easy maintenance

(The propulsion efficiency here refers to "specific thrust", that is, the thrust generated by the consumption of unit propellant per unit time, also known as "specific impulse", the same below; nitrogen tetroxide decomposes to produce brown-red nitrogen dioxide, so brown-red smoke can be seen when the rocket takes off, photographer @阿毛)

▼

Structurally

The rocket diameter is increased to

The limit size of railway transportation in my country

3.35 m

Due to the larger diameter and stronger propellant

Even if we return to a two-stage rocket

It can also reach orbital speed

(A train carrying rocket parts to the Xichang Launch Center, photographer @Donald)

▼

The upgraded new generation of rockets

First

Named FB-1

It enabled our country to

Launching a satellite weighing more than 1 ton

It also achieved the first "three stars in one rocket"

(The Storm-1 model parked at the Jiuquan Satellite Launch Center, photographer @勾炳宸)

▼

Second

It is the Long March 2 (CZ-2)

Its low-Earth orbit payload is about

1.8 tons

Successfully launched

my country's first recoverable satellite

This is the first step in manned space flight.

(Note: The "low-Earth orbit" here refers to an orbit with an altitude of about 200-400 kilometers. Unless otherwise specified, this range will be used in the following text; the picture below shows the first recoverable satellite launched and recovered by my country, Pioneer-1, from @VCG)

▼

However, at this time

China's low-Earth orbit payloads

Still not over 2 tons

Small rocket category

Bigger satellites, farther stars

The hope for manned space flight and the dream of a space station

All will be handed over to the next generation of rockets

Become their glorious mission

02

Medium rocket mission

Medium-sized rockets for low-Earth orbit payloads

Between 2-20 tons

Improved on the basis of Long March 2

Long March 2C (CZ-2C)

Long March 2D (CZ-2D)

Nearly 10 meters higher than the original rocket

Can carry more fuel

Plus the optimization of materials and engines

Its low-Earth orbit payload can be increased to about

4 tons

Entering the ranks of medium-sized rockets in one fell swoop

Become one of the main forces in launching recoverable satellites

(The Long March 2D also uses some of the Long March 4's technology. The picture below shows the Long March 2D launching into space. Photographer: @曾诚宇)

▼

However

These satellites usually operate in

Low Earth orbit at an altitude of several hundred kilometers

In comparison

The orbit altitude of meteorological satellites is about 1000 kilometers

Navigation satellites can reach about 20,000 kilometers

Another type of orbit is even more distant.

Its altitude is about 36,000 km

The orbital plane coincides with the equatorial plane

Satellites operating here

Can always remain relatively still with the ground

This is the unique geostationary orbit

In an ideal situation

Only three satellites need to be deployed here

It can basically cover global communications

(Sketch of spacecraft orbits at different altitudes, courtesy of @陈思琪&陈随/Planetary Research Institute)

▼

But to reach geostationary orbit

But it's not easy

Satellites must use a "multi-step jump" approach

First, at a speed of about 10 km/s

Entering a transition track

Then through precise track change

Position the vehicle in the target orbit

This means

We also need

Rockets that fly farther, higher and more accurately

(The transition orbit mentioned above is the "geosynchronous transfer orbit", and the figure below is a schematic diagram of the launch process of a geostationary orbit satellite. Map by @陈思琪&陈随/Planetary Research Institute)

▼

to this end

The engineers first tried

Still

Vertical upgrade

But people are now faced with

Two difficult choices

First

It is based on the Long March 2C.

Using a new cryogenic propellant in the third stage

"Liquid Hydrogen + Liquid Oxygen"

Replacement of traditional room temperature propellants

New propellant further increases propulsion efficiency

But the engine technology is more difficult

Liquid hydrogen has a temperature below -253°C and is flammable and explosive

Therefore, from the engine technology

To fuel storage, transportation and refueling

Everything starts from scratch

(The Long March 3 series rocket is being debugged in the final assembly plant, with the disassembled fuel tank visible. Photographer: @宿东)

▼

Second

Based on the Storm 1

The third level still uses mature technology

Conventional room temperature propellant

Lower risk, greater certainty

One side is high technology

One side is low risk

This choice is not a good one.

People hold different opinions and argue endlessly

Until the chief engineer of China Communications Satellite

Ren Xinmin stood up and said

(Quoted from Ren Xinmin, with reference to "Sky Arrow" by China Academy of Launch Vehicle Technology)

▼

If China wants to become a space power by the end of this century and shake off the label of backwardness, it must set its sights on the peak of contemporary rocket engines… The space industry itself is a big risk. If you are afraid of failure and risks, why bother with space industry!

This is a powerful statement

About 10 years later

Successfully carried our country

Geostationary satellite launch banner

The first solution is to take

The third stage uses "liquid hydrogen + liquid oxygen" propellant

Long March 3 (CZ-3)

(Structural comparison between Long March 2C and Long March 3, drawn by @陈随/Planetary Research Institute)

▼

The third-stage propellant tank

Antifreeze, anti-seepage, moisture-proof, heat insulation

The engine can then perform secondary ignition

Speed ​​up the satellite again

Entering transition orbit

Further improvements were made to

Long March 3A (CZ-3A)

For the first time, our satellite

Sending it to the Moon

Earth-Moon transfer orbit

Since then, China's space history

The Chang'e era began

(Long March 3A launches the Chang'e-1 lunar exploration satellite, photographed on October 24, 2007, by photographer @雨水)

▼

at the same time

Still using traditional room temperature propellants

Another upgrade plan

Also in progress

This is

Long March 4 series

(CZ-4A, CZ-4B, CZ-4C)

They are the main force in launching sun-synchronous orbit satellites.

(Long March 4B, photographer @史悦)

▼

This is a special kind of track.

Its orbital plane can rotate around the Earth's axis

The rotation period is consistent with the Earth's revolution period.

So every time the satellite passes over the same location

Always maintain the same sunlight conditions

Very suitable for meteorological and ground observation

But the inclination of this orbit

Often more than 90°

Requires a lot of thrust from rockets

To change the flight direction

(Synopsis of a sun-synchronous orbit, taking the orbit of the Fengyun-1 satellite as an example, drawn by @陈思琪&陈随/Planetary Research Institute)

▼

So when September 7, 1988

The Long March 4A carried the first

Fengyun-1 meteorological satellite

Successfully entered the 900-kilometer-high, 99-degree inclination

Sun-synchronous orbit time

It has attracted great attention at home and abroad

The era when my country relies on foreign meteorological satellite data

It also officially declared the end

(Long March 4B launches the China-Pakistan Earth Resources Satellite deployed in a sun-synchronous orbit, photographer @阿毛)

▼

So far

my country's medium-sized launch vehicle

Low Earth Orbit Payload

Reached about

6 tons

However

To realize manned space flight in the future

The load requirement will be at least 8 tons

But at this time, the takeoff thrust of the single-core rocket

Almost nothing can be added

What should I do?

(A single-core rocket has only one core stage, like a "pillar supporting the sky". The picture below shows the Long March 3A ready for launch. Image source: @VCG)

▼

The answer is

Horizontal bundling

For example

Based on the Long March 2C

Proper lengthening in the vertical direction

To increase the propellant reserve

Horizontally

Then "bundle" 4 smaller rockets

Each is 15.3 meters high and 2.25 meters in diameter

It is for "booster"

Takeoff

4 intermediate core stage engines

4 booster engines

A total of 8 engines ignited together

The scene is spectacular

(A rocket engine with four boosters bundled together; the picture below is the Long March 3B for illustration, photographer @史悦)

▼

This is

The earliest strap-on rocket

Long March 2 Bundle (CZ-2E)

Its takeoff thrust can reach twice that of Long March 2C

The payload in low-Earth orbit reaches about

9.5 tons

From the beginning of its development to its first launch

It only took 18 months

(Comparison of the structures of Long March 2C and Long March 2 bundle, drawn by @Chen Sui/Planetary Research Institute)

▼

but

Really realized

China's dream of manned space flight

The famous

Long March 2F (CZ-2F)

(Long March 2F is transferred to the launch tower, using vertical assembly, vertical testing, and vertical transportation. Photographer: Sun Haiying)

▼

Its shape is very unique

Compared with the Long March 2

On top of the fairing

Added a pointed "hat"

It is called the "Escape Tower"

(Schematic diagram of the Long March 2F escape system structure, drawn by @陈随/Planetary Research Institute)

▼

This is a safety device

15 minutes before departure

Within 120 seconds after takeoff

If a rocket has an accident

The escape engine can be ignited immediately

The orbital module and return module carrying the spacecraft

Rapidly separated from the arrow body

Helping astronauts escape danger

It can be called a "tower of life"

(Long March 2F escape tower, this rocket will carry the Shenzhou 7 manned spacecraft, picture source @VCG)

▼

Life-saving system including escape tower

Plus backup of the main control system

And automatic fault detection system

Three-pronged approach

The design reliability of Long March 2F

0.91 from the Long March 2 bundle

Increased to 0.97

(maximum 1)

And it lived up to expectations

On October 15, 2003

China's first astronaut Yang Liwei

Safely sent into space

This makes our country the third

Countries that have successfully launched manned spacecraft

(Shenzhou V's return capsule successfully returned, image source @CCTV.com)

▼

During his 21 years of service

Long March 2F has made great achievements

From Shenzhou 1 to 11

To Tiangong-1-2

Total launches

5 unmanned spacecraft, 6 manned spacecraft

And 2 space laboratories

It still maintains a 100% launch success rate.

It is truly worthy of the name

"Magic Arrow"

(Long March 2F "changing its hat", the Tiangong-1 ship-rocket combination docking, and the word "Shenjian" can be seen partially on the rocket body, photographer @宿东)

▼

Long March 2 series

Both are two-stage rockets

And if based on the Long March 3A

Lengthening, bundling

It can form a three-stage bundled rocket

Long March 3B (CZ-3B)

Long March 3C (CZ-3C)

(Structural comparison of Long March 3A, Long March 3B and Long March 3C, drawn by @陈随/Planetary Research Institute)

▼

Especially the Long March 3B

As a three-stage rocket with four boosters bundled together

In the past 20 years

They are all the "top configuration" of China's launch vehicles

Its low-Earth orbit payload exceeded 10 tons for the first time

Reach about

11.5 tons

Almost with one arrow

Becoming the absolute main force of my country's medium and high orbit launch

(On September 23, 2019, the Long March 3B carried the 47th and 48th BeiDou satellites to an orbit at an altitude of about 20,000 kilometers. Photographer @史悦)

▼

Chang'e 3 and Chang'e 4 were successfully launched

Built China's lunar ladder

(The Long March 3B successfully launched the Chang'e 4 lunar probe, which will represent the first landing on the back of the moon for all mankind. Photographer @Jiang Tao)

▼

However

As the saying goes

(Quoted from "Shenjian Lingxiao: The Development History of the Long March Series of Rockets")

▼

When China's launch vehicles woke up from the surprise of continuous success,

It will face four powerful opponents.

By the beginning of the 21st century

American, European, Russian

Large commercial rockets are unveiled one after another

Some have a carrying capacity of up to

Twice as much as Long March 3B

It is safer, cleaner, quicker to deploy and cheaper

In comparison

China's launch vehicle at that time

Almost every aspect is dwarfed

(Comparison between Long March 3B and other large foreign rockets of the same period, drawn by @陈随/Planetary Research Institute)

▼

once

All-round upgrade

Imminent

On propellant

Used for nearly 40 years

"Uniform dimethylhydrazine + nitrogen tetroxide"

Will be gradually abandoned

Switch to a combination of "kerosene + liquid oxygen"

Combustion produces carbon dioxide and water

Not only is the whole process non-toxic and pollution-free

And the cost is greatly reduced

engine

Also upgraded with the change of propellant

Propulsion efficiency can be further improved by about 15%

Booster

The height is nearly 27 meters

Nearly twice the size of all previous boosters

This is

Long March 7 (CZ-7)

(The "propulsion efficiency" mentioned above refers to the specific thrust at sea level; the figure below is a structural comparison between the Long March 3B and the Long March 7, drawn by @陈随/Planetary Research Institute)

▼

Its low-Earth orbit payload is about

14 tons

Enough to launch a 13-ton

Tianzhou-1 cargo spacecraft

In China's "space station era"

Playing a vital role

future

It will also gradually replace

Mission of the Long March 2, 3, and 4 series

Undertakes about 80% of my country's launch missions

Become the supporter of China's space dream

Mainstay

(During the transfer of the Long March 7, the people and vehicles below look very small; the design reliability of the Long March 7 is 0.98, which is higher than that of the Long March 2F. Photographer: @宿东)

▼

So far

my country's medium-sized launch vehicle

All appeared

To launch a payload of more than 20 tons into low-Earth orbit

We have to count on the next generation of players.

03

The Game of Large Rockets

October 2014

Hainan Wenchang Satellite Launch Center completed

Its latitude is lower and closer to the equator

Can make full use of the earth's rotation speed

Improve rocket carrying efficiency

And when launching a geostationary orbit satellite

It can also reduce the rocket's trajectory change and flight distance

Compared with Jiuquan Launch Center

The quality of satellite insertion and positioning

Can increase 16.3%-18.5%

(The above data comes from the "Sky Arrow" of the China Academy of Launch Vehicle Technology; the figure below is the distribution map of China's satellite launch centers, drawn by @陈思琪&陈随/Planetary Research Institute)

▼

on the other hand

It is China's first coastal launch base.

The southeast direction is almost entirely ocean within 1,000 km

Ensure the safety of debris falling

(Hainan Wenchang launch tower, photographer @陈肖)

▼

But more importantly

Since then

Rocket parts can be transported by sea

Completely get rid of the 3.35-meter diameter

Rail transport restrictions

(The Yuanwang 21 rocket carrier is loading Long March 5 components, photographer @宿东)

▼

So far, everything is ready

China's first large carrier rocket

Long March 5 (CZ-5)

Out of nowhere

As a two-stage rocket

It is nearly 57 meters high.

Equivalent to a 20-story building

Almost on par with existing three-stage rockets

The diameter of the intermediate core stage has been increased from 3.35 meters to 5 meters.

The diameter of the four boosters increased from 2.25 meters to 3.35 meters

It is a veritable "giant"

Nicknamed "Fat Five"

(Structural comparison between Long March 7 and Long March 5, drawn by @陈随/Planetary Research Institute)

▼

also

Compared with Long March 7

The intermediate core stage is completely replaced

"Liquid hydrogen + liquid oxygen" cryogenic propellant

And equipped with a new engine

Number of booster engines

It also doubled to 8

Takeoff

A total of 10 engines will ignite and spray at the same time

Takeoff thrust increased by approximately 50%

The payload in low-Earth orbit can reach about

25 tons

(Long March 5 is launched into space. Because both stages of the intermediate core stage use cryogenic hydrogen-oxygen propellants, it is also called the "Ice Arrow". Its tail flame is blue. Photographer @陈肖)

▼

This is China’s

The largest take-off mass and the thickest core diameter

The rocket with the highest carrying capacity

second only to

Falcon Heavy launch vehicle

Delta IV Heavy launch vehicle

Ranked third among active rocket teams in the world

(The huge Long March 5, photographer @陈肖)

▼

November 3, 2016

The first Long March 5

The first flight was a success under the watchful eyes of the public

And for the first time using a launch vehicle

Sending a satellite directly into geostationary orbit

In the next 30 years

Even longer years

It will also witness

Lunar exploration, Mars exploration

Solar Orbiter Space Telescope and other deep space exploration missions

More historic moments

(November 3, 2016, 20:43:13.998, Long March 5 was launched for the first time, photographer @CNAurora)

▼

But the dream of super rocket

It doesn’t end here

A look at the world's aerospace

The most powerful rocket ever built

It's the Saturn V of the United States.

Its low-Earth orbit payload is as high as 140 tons

Since 1967

To escort the Apollo program

Its record has not been surpassed so far.

(On November 9, 1967, Saturn V was launched for the first time, carrying Apollo 4, and has now been retired. Image source: @NASA)

▼

After decades of non-stop pursuit

It is expected to be between 2028 and 2030

China's heavy rocket

Finally it will come into being

Long March 9

Its total length will exceed 100 meters

The core diameter is close to 10 meters

Twice as big as the "Fat Five"

The payload in low-Earth orbit will exceed

100 tons

Even if you only imagine it in your mind

It is also enough to shock people

By then

It will carry

China's manned lunar landing

Mars Sample Return

Even the exploration of outer planets in the solar system

A more difficult task

04

A long journey

Over the past 50 years

China's launch vehicle fleet grows

Big rockets are growing in size

Small rockets also blossom

Long March 6 (CZ-6)

Can be quickly launched using a simple launcher

It once created a record of launching 20 satellites in one rocket

(The Long March 6 was successfully launched using a simple launcher, photographer @李岗)

▼

Long March 11 (CZ-11)

Length reduced to about 20 meters

Reduced to 2 meters in diameter

Can be launched directly from offshore platforms

(Long March 11 launched at sea, image source: @VCG)

▼

Kuaizhou-1

More compact

Its diameter is only 1.4 meters

The minimum interval between two launches is only 6 hours

Quick response and flexible deployment

(Kuaizhou-1 taking off directly, image source: @VCG)

▼

also

Many private rockets are becoming more mature

Reusable rockets are also under development

(The erection process of China's private rocket Hyperbola-1, photographer @陈肖)

▼

all in all

Represented by the "Long March" series

China's launch vehicle capabilities will become increasingly comprehensive

To cover different types of tracks

To the Moon and Mars

To the stars beyond

Although in every mission

They are just the beginning of the story.

Never participated in the ending of the story

Once the separation is successful

They will retire

Or disappear in the atmosphere

(The booster of the Long March 7 separated and fell after completing its work. Photographer: @陈肖)

▼

Or fall into the wilderness sea

(The body of the Long March 2D rocket fell in the wilderness, photographer @在远方的阿伦)

▼

Only satellites and spacecraft are left

Continue to run towards the distant stars

As the saying goes

(Quoted from Li Bai's "Xia Ke Xing")

▼

When the work is done, I will leave, hiding my identity and name

But that’s their mission

Like the pinnacle of science

It is also passed on from generation to generation.

To be able to climb over

Wait until

Beidou array, Shenzhou speeding

Chang'e flies to the moon and lands on Mars

Tianzhou made a round trip, and Tiangong was completed

…

This is the flying road

The most glorious moment

(Long March 7 takes off, the fire reflected on the sky and sea is dazzling, photographer @陈肖)

▼

Creative Team

Written by: Master Zhen, Ai Lanxing

Image: Ren Bingxu

Design: Chen Sui

Map: Chen Siqi

Proofreading: Zhang Zhao, Yunwukongcheng

Expert review

Dr. Zhang Boyong, China Academy of Launch Vehicle Technology

[Acknowledgments] The creation of this article received great support from photographer A Mao, and I would like to express my special gratitude.

【References】

[1] Chen Minkang, Ru Jiaxin. The development of the Long March rocket series[M]. Shanghai Science and Technology Education Press, 2007.

[2] China Academy of Launch Vehicle Technology. Arrows to the Sky: Long March Rockets Open the Way to the Sky[M]. China Aerospace Press, 2008.

[3] Li Chengzhi. A Draft History of the Development of China's Space Technology[M]. Liaoning Education Press, 2006.

[4]Editorial Committee of World Space Launch Vehicle Encyclopedia. World Space Launch Vehicle Encyclopedia[M]. China Aerospace Press, 1996.

[5] Ran Longsui. Aerospace Engineering Design Practice[M]. China Aerospace Press, 2013.

[6] Liu Jiayun, Li Xiaomin, Guo Guiping. Introduction to Aerospace Technology[M]. Beijing University of Aeronautics and Astronautics Press, 2014.

... The End ...

Planetary Research Institute

A group of National Geographic fans, focusing on exploring the extreme world