THE CHANDRAYAAN PROGRAMME: 1

Reading Time: 8 minutes

Since the past few days, there has been a buzz around everywhere, Not only in India but the world around. For some, it’s a challenge for others its pride. So, what’s it all about? You are right, for every Indian, it’s a moment of great pride and honour to launch our next moon mission Chandrayaan-2.  But before discussing it, let us brush up our knowledge on the whole series of Indian Lunar Mission “THE CHANDRAYAAN PROGRAMME”.

Why Moon?

Since childhood we have been witnessing the white round moon ‘our chandamama’ grow big and small daily. Many of us had dreamt to go to the moon and play with the stars. But growing up we realise that the moon is not our neighbour next window but yes somewhere closer to our childhood. So, let’s fulfil our childhood dream and fasten our seatbelts to go to moooooooon!!!!!!

 Being Earth’s only natural satellite moon provides the best linkage to Earth’s early history. It had witnessed each and every moment of our existence. It offers a great historical record of the inner Solar system environment. Though there are a few explained models, the origin of the Moon still needs further explanations. Extensive mapping of the lunar surface, to study variations in lunar surface composition is essential to trace back the origin and evolution of the Moon and this can further be helpful to study the origin and evolution of solar system and universe.

Chandrayaan programme is India’s Lunar Exploration Program. It is a series of outer space missions under the Indian Space Research Organisation (ISRO). The program consists of different parts which are a lunar orbiter, impactor, future lunar lander and rover spacecraft.

The Chandrayaan project was announced on 15 August 2003 by then Prime Minister Atal Bihari Vajpayee. This program was launched to boost Indian space programs and embarking India’s name in history.

Chandrayaan is a multi-phase mission-

  • The first phase includes the launch of CHANDRAYAAN – 1 which was a lunar orbiter.
  • The second phase includes the launch of soft lander/Rover Vikram and Pragyan as CHANDRAYAAN-2.
  • The third phase is planned to be an in-situ sampling collection expected in 2024 as CHANDRAYAAN-3.

CHANDRAYAAN-1

Launched on 22 October 2008 Chandrayaan 1 was the first milestone for Indian lunar programme. It was launched by ISRO from Satish Dhawan Space Centre, Sriharikota. It was unique in its sense that it was researched and developed fully in India by Indian scientists and researchers. The vehicle was inserted in the lunar orbit on 8 November 2008. On 14 November 2008, the Moon Impact Probe (MIP) separated from the Chandrayaan orbiter at 14:36 UTC and struck the south pole in a controlled manner, making India the fourth country in the world to place its flag on the Moon. The probe hit near the crater Shackleton at 15:01 UTC (20:31 IST). The location of impact of the probe was named as Jawahar Point.

The estimated cost of the project was around ₹386 crore (USD 56 million). Along with other objectives, the area around polar regions was of high interest as it may contain ice and may result in the discovery of water on the moon. The lunar mission in total carried 11 payloads, five of them were ISRO payloads and six payloads from other space agencies including NASA, ESA, and the Bulgarian Aerospace Agency. The payloads form these agencies were carried free of cost.

The stated objectives of this mission were: –

  • perform high-resolution remote sensing of the moon in – visible, near-infrared (NIR), low energy X-rays and high-energy X-ray regions
  • survey the lunar surface to produce a complete map of its chemical characteristics
  • prepare a three-dimensional atlas of both near and far side of the moon
  • conduct chemical and mineralogical mapping of the entire lunar surface for distribution of mineral and chemical elements such as Magnesium, Aluminium, Silicon, Calcium, Iron and Titanium and also high atomic number elements such as Radon, Uranium & Thorium.
  • test the impact of a sub-satellite (Moon Impact Probe – MIP) on the surface of the Moon as a forerunner for future soft-landing missions

The mission carried five scientific payloads from India, according to the ISRO these were:

  • Terrain Mapping Camera (TMC), which provided a high-resolution map of the moon.
  • Hyper Spectral Imager (HySI), which performed the mineralogical mapping.
  • Lunar Laser Ranging Instrument (LLRI), which returned information about the moon’s topography (height of certain features).
  • High Energy X-ray Spectrometer (HEX), which examined radioactive elements on the surface.
  • Moon Impact Probe (MIP), which was intentionally crashed into the moon’s south pole. Its impact helped Chandrayaan-1 in its search for lunar water.

What happened when: Timeline of  Chandrayaan – 1

15th August 2003: Chandrayaan programme was announced by Prime Minister Atal Bihari Vajpayee

22nd October 2008: Chandrayaan-1 takes off from the Satish Dhawan Space Centre, Sriharikota

8th November 2008: Chandrayaan-1 enters the Lunar Transfer Trajectory

14th November 2008: The Moon Impact Probe ejects from Chandrayaan 1 and crashes near the lunar South Pole — confirms the presence of water molecules on Moon’s surface

28th August 2009: Chandrayaan-1 programme ends

What we Achieved from this mission?

1. Water on the Moon 

On 18 Nov 2008, the Moon Impact Probe was released from Chandrayaan at a height of 100km. During its descent to the moon surface, Chandra’s Altitudinal Composition Explorer (CHACE) recorded evidence of water on the moon. This discovery was later confirmed by JPL-Brown University payload – Moon Mineralogy Mapper (M3), a payload by NASA. M3 detected spectral lines near the wavelengths in the range of 2.8 – 3.0 microns, a property attributed to water and Hydroxyl ions. It is believed that the formation of Hydroxyl ions and water molecules on the lunar surface is an ongoing process. 

According to European Space Agency (ESA) scientists, the lunar regolith (a loose collection of irregular dust grains making up the Moon’s surface) absorbs hydrogen nuclei from solar winds. The hydrogen nuclei and oxygen present in the dust grains interact and are expected to produce hydroxyl (HO) and water (H2O).

 

 

 2. Imaging of North and South Pole of the Moon

This was done by two different devices namely –

 

  • Terrain Mapping Camera (TMC) 

THE CHANDRAYAAN PROGRAMME: 1

THE CHANDRAYAAN PROGRAMME: 1

  • Hyper Spectral Images (HySI)

THE CHANDRAYAAN PROGRAMME: 1

THE CHANDRAYAAN PROGRAMME: 1

3. 3-D profile of Clavius (one of the largest craters on moon)

Lunar Laser Ranging Instrument (LLRI) mapped Clavius, the third largest crater on the near side of the moon, a feature observable with little aid and even with the naked eye.

The mineral content on the lunar surface was mapped with the Moon Mineralogy Mapper (M3), a NASA instrument on board of the orbiter. The Oriental Basin region of the Moon was mapped, and it indicates an abundance of iron-bearing minerals.

THE CHANDRAYAAN PROGRAMME: 1

Chandrayaan-1 Imaging X-ray Spectrometer: The purple arrow shows the spacecraft track over the Moon; the different coloured rectangles show the area of the Moon that C1XS was looking at. The yellow and red areas show strong X-ray signals that correspond to Silicon, Aluminium and Magnesium, at the right hand end the green/turquoise area shows X-rays due to Calcium.

4. Mapping of various minerals

The mineral content on the lunar surface was mapped with the Moon Mineralogy Mapper (M3), a NASA instrument on board of the orbiter. The Oriental Basin region of the Moon was mapped, and it indicates an abundance of iron-bearing minerals.

THE CHANDRAYAAN PROGRAMME: 1

Chandrayaan-1 Imaging X-ray Spectrometer: The purple arrow shows the spacecraft track over the Moon; the different coloured rectangles show the area of the Moon that C1XS was looking at. The yellow and red areas show strong X-ray signals that correspond to Silicon, Aluminium and Magnesium, at the right hand end the green/turquoise area shows X-rays due to Calcium.

5. Mapping of Apollo landing sites

In January 2009, ISRO announced the completion of the mapping of the Apollo Moon missions landing sites by the orbiter. Six of the mapped sites included landing sites of Apollo 12, 14 and 16 (can be referred in the previous image).

 

6. Radiation environment around the Moon

Radiation Dose Monitor or RADOM-7 (a payload from the Bulgarian Academy of Sciences) examined the radiation environment around the moon. 

THE CHANDRAYAAN PROGRAMME: 1

 

End of the mission

The mission was launched on 22 October 2008 and was expected to operate for two years. However, around 20:00 UTC (11:00 IST) on 28 August 2009 communication with the spacecraft was suddenly lost. Chandrayaan-1 made 3,400 orbits of the moon and continued transmitting data until 28 August 2009, when controllers permanently lost communication with the spacecraft. The probe had operated for 312 days.  Earlier it was expected that the craft crashed into the lunar surface but in 2016 it was found still to be in the orbit. Although the mission lasted less than its expected duration, but a team of scientists from ISRO stated the mission to be successful as it had achieved 95% of its desired objectives in this time duration. 

Chandrayaan 1 was a major success not only for Indian fraternity but also to Space Science as a whole. It expanded India’s footprint in space and proposed a whole together new dimensions to space. Chandrayaan-1 was lauded with a number of awards and recognitions as below –

  • The American Institute of Aeronautics and Astronautics (AIAA) has selected ISRO’s Chandrayaan-1 mission as one of the recipients of its annual AIAA SPACE 2009 awards.
  • The International Lunar Exploration Working Group awarded the Chandrayaan-1 team the International Co-operation Award in 2008.
  • US-based National Space Society awarded ISRO the 2009 Space Pioneer Award in the science and engineering category.

 

So, this was the first Lunar mission of India, tricolour for the first time fluttered on the moon’s surface. Stay tuned for the upcoming section on Chandrayaan-2, which will surely set new heights to the Indian Space Research and fill us with immense pride and honour.

Thank you!

Keep reading, keep learning!

TEAM CEV

Why do Rockets love to fail?

Reading Time: 8 minutes

Author
Deepak Kumar
Propulsion Engineer, Dept. of Propulsion, STAR

“Rockets, they really don’t wanna work, they like to blow up a lot”

 

         – Elon Musk

If you take look at all the List of spaceflight-related accidents and incidents – Wikipedia , you’ll realize there have been countless failures. That the answer to “How many”.

 

Rockets can fail anytime. Moreover, a rocket isn’t a simple machine at all. A massive structure having around 2.5 billion dynamic parts is likely to fail anytime if any of these parts says, “ I can’t do this anymore, I’m done”.

 

Coming to some of the well known Rocket Failures, this will help you learn how rockets fail!

 

1. The Space Shuttle Challenger Disaster

Why do Rockets love to fail?

The spaceflight of Space Shuttle carried a crew of 7 members, when it disintegrated over the Atlantic Ocean. The disintegration was caused due to the failure of one of Solid Rocket Boosters(SRB). The SRB failed during the lift-off.

 

The failure of SRB was caused due to O-Rings. O-ring is mechanical gasket that is used to create a seal at the interface. And here, that interface was between two fuel segments. O-Ring was designed to avoid the escaping of gases produced due to burning of solid fuel. But extreme cold weather on the morning of launch date, the O-Ring became stiff and it failed to seal the interface.

Why do Rockets love to fail?

This malfunctioning caused a breach at the interface. The escaping gases impinged upon the adjacent SRB aft field joint hardware( hardware joining the SRB to the main structure) and the fuel tank. This led to the separation of the Right Hand SRB’s aft field joint attachment and the structural failure of external tank.

Why do Rockets love to fail?

In the video below, the speaker mentions about the weather being chilly on that morning and icicles formed on the launch pad in the morning. One of SRB is clearly visible making its own way after the failure.



2. The Space Shuttle Columbia Disaster

Unlike the above failure, this failure occurred during the re-entry. But again, the story traces back to the launch. During the launch, a piece of foam broke off from the external fuel tank and struck the left wing of the orbiter.

Why do Rockets love to fail?

This is an image of orbiter’s left wing after being struck by the foam. The foam actually broke off from the bi-pod ramp that connects the orbiter and fuel tank.

Why do Rockets love to fail?

The foam hit the wing at nearly a speed of 877 km/h causing damage to the heat shield below the orbiter. The piece of foam that broke off the external fuel tank was nearly the size of a suitcase and could have likely created a hole of 15–25 cms in diameter.

Why do Rockets love to fail?

The black portion below the nose you see is the carbon heat shield of orbiter.

On Feb 1,2003 during the re-entry, at an altitude of nearly 70 km, temperature of wing edge reached 1650 °C and the hot gases penetrated the wing of orbiter. Immense heat energy caused a lot of dange. At an altitude of nearly 60 km, the sensors started to fail, the radio contact was lost, Columbia was gone out of control and the left wing of the orbiter broke. The crew cabin broke and the vehicle disintegrated.

 

 

You can clearly see the vehicle disintegrating. **The video is a big one, hang tight. 😉

 

3. The N1 Rocket Failure

Not many people know about this programme. It was started in 1969 by the Russians. N1 rocket remains the largest rocket ever built till date. The rocket had its last launch in 1972. During this tenure, the were four launches, all of them failed. Yes you heard it right, ALL OF THEM FAILED.

Why do Rockets love to fail?

Before discussing the failures, there is one thing that I never forget to mention about this rocket. Rockets rely on TVC(Thrust Vector Control) to change the direction of the thrust. The nozzle direction is changed to alter the direction of thrust.

Why do Rockets love to fail?

This is TVC. But in case of N1 Rocket, there was something called Static Thrust Vectoring. There were 30 engines in stage 1, 8 engines in stage 2, 4 engines in stage 3 and 1 in stage 4.

Why do Rockets love to fail?

There were 24 on the outer perimeter and the remaining 6 around the centre.

In order to change the direction of rocket, the thrust was changed in the engines accordingly. The engines didn’t move like TVC at all.

Now coming to the failed launches:

Launch 1:

The engines were monitored by KORD(Control of Rocket Engines). During the initial phase of flight, a transient voltage caused KORD to shut down the engine #12. Simultaneously, engine #24 was shut down to maintain stability of the rocket. At T+6 seconds, pogo oscillation( a type of combustion instability that causes damage to the engine) in the #2 engine tore several components off their mounts and started a propellant leak. At T+25 seconds, further vibrations ruptured a fuel line and caused RP-1 to spill into the aft section of the booster. When it came into contact with the leaking gas, a fire started. The fire then burned through wiring in the power supply, causing electrical arcing which was picked up by sensors and interpreted by the KORD as a pressurization problem in the turbopumps.

Launch 2:

Launch took place at 11:18 PM Moscow time. For a few moments, the rocket lifted into the night sky. As soon as it cleared the tower, there was a flash of light, and debris could be seen falling from the bottom of the first stage. All the engines instantly shut down except engine #18. This caused the N-1 to lean over at a 45-degree angle and drop back onto launch pad 110 East. Nearly 2300 tons of propellant on board triggered a massive blast and shock wave that shattered windows across the launch complex and sent debris flying as far as 6 miles (10 kilometers) from the center of the explosion. Just before liftoff, the LOX turbopump in the #8 engine exploded (the pump was recovered from the debris and found to have signs of fire and melting), the shock wave severing surrounding propellant lines and starting a fire from leaking fuel. The fire damaged various components in the thrust section leading to the engines gradually being shut down between T+10 and T+12 seconds. The KORD had shut off engines #7, #19, #20, and #21 after detecting abnormal pressure and pump speeds. Telemetry did not provide any explanation as to what shut off the other engines. This was one of the largest artificial non-nuclear explosions in human history.

Launch 3:

Soon after lift-off, due to unexpected eddy and counter-currents at the base of Block A (the first stage), the N-1 experienced an uncontrolled roll beyond the capability of the control system to compensate. The KORD computer sensed an abnormal situation and sent a shutdown command to the first stage, but as noted above, the guidance program had since been modified to prevent this from happening until 50 seconds into launch. The roll, which had initially been 6° per second, began rapidly accelerating. At T+39 seconds, the booster was rolling at nearly 40° per second, causing the inertial guidance system to go into gimbal lock and at T+48 seconds, the vehicle disintegrated from structural loads. The interstage truss between the second and third stages twisted apart and the latter separated from the stack and at T+50 seconds, the cutoff command to the first stage was unblocked and the engines immediately shut down. The upper stages impacted about 4 miles (7 kilometers) from the launch complex. Despite the engine shutoff, the first and second stages still had enough momentum to travel for some distance before falling to earth about 9 miles (15 kilometers) from the launch complex and blasting a 15-meter-deep (50-foot) crater in the steppe.

 

Launch 4:

The start and lift-off went well. At T+90 seconds, a programmed shutdown of the core propulsion system (the six center engines) was performed to reduce the structural stress on the booster. Because of excessive dynamic loads caused by a hydraulic shock wave when the six engines were shut down abruptly, lines for feeding fuel and oxidizer to the core propulsion system burst and a fire started in the boat-tail of the booster; in addition, the #4 engine exploded. The first stage broke up starting at T+107 seconds and all telemetry data ceased at T+110 seconds.

Besides the mechanical failures, the rockets might fail due to a minute discrepancy in program’s as in case of Ariane 5.

Ariane 5: After 37 seconds later, the rocket flipped 90 degrees in the wrong direction, and less than two seconds later, aerodynamic forces ripped the boosters apart from the main stage at a height of 4km. This caused the self-destruct mechanism to trigger, and the spacecraft was consumed in a gigantic fireball of liquid hydrogen.

The fault was quickly identified as a software bug in the rocket’s Inertial Reference System. The rocket used this system to determine whether it was pointing up or down, which is formally known as the horizontal bias, or informally as a BH value. This value was represented by a 64-bit floating variable, which was perfectly adequate.

However, problems began to occur when the software attempted to stuff this 64-bit variable, which can represent billions of potential values, into a 16-bit integer, which can only represent 65,535 potential values. For the first few seconds of flight, the rocket’s acceleration was low, so the conversion between these two values was successful. However, as the rocket’s velocity increased, the 64-bit variable exceeded 65k, and became too large to fit in a 16-bit variable. It was at this point that the processor encountered an operand error, and populated the BH variable with a diagnostic value.

That’s your answer to “why”. Rockets can fail anytime due even a small malfunction in one of those 2.5 billion dynamic parts or even a small programming error.

Hope you enjoyed the writings up there!

Thank You!

Source: Google and Wikipedia

 

 

Looking forward to excel in rocket building?

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SPACE SHUTTLES: The Ultimate Vehicles

Reading Time: 11 minutes

WARMING-UP……..

Probably you are going to witness the greatest technological feat of human civilization that remarks not just technological advancement but bespeaks one of the greatest establishment of humankind as a whole.

Moreover, on a special note, I would like you to consider the fact that it is the core human tendency to break his own records which every time seems to appear, the final last update. I would not claim for the future but comparing the past then certainly this masterstroke ranks first.

This whole story remarks some of the most distinguishing characteristics of human society. The story of the massive vehicle taking off from womb of mother earth with million-ton heavy rocket boosters and touching down back to earth with elegant astronauts inside. This signifies the display of greatest courage, dedication, commitment and above all international cooperation and brotherhood.

I assure you that none of my blogs has the capability to swing your mind like this can. If you want to experience a complete thrill then follow this blog after you go through the Higgs boson and nuclear fusion on earth.

So that was the warm-up part of the blog, let us uncover the bottom line of it.

FROM STAR-GAZING TO MARS MISSION

Humans earlier used to sleep under the open skies and this chance of glaring the ubiquitous, vast and boundless space, the world of stars and planet have ignited the humans to know and visit them someday.

From those days of dreaming, the history records the development of theories of movement of heavenly bodies by Galileo Galilei and Isaac Newton, the launching of first liquid-fuel propelled rocket by father of rocketry, Robert Goddard, then the first human in space from Russia and landing on the moon by America. Skimming through those pages we see a story of great ups and downs and we get to know how all those audacious and beautiful things were accomplished.

These achievements are not just for the sake of scientific fantasy, in fact, is aimed at providing the exceptional services of communication, aviation, and information technology as an immediate outcome. On the other hand, remarks the very first step of humankind to become interplanetary species so as to surpass the danger of extinction in the future due to earth turning hostile.

We have talked a lot about “in general” of the topic and let us turn to more technical aspects. Let us get to know more about some major technical details about the designing, launching and maneuvering, re-entering and landing of the space shuttles. Moreover, USA’s NASA has done a whole lot of work on the space shuttle. So we will talk specifically about those American space shuttles and also talk about major timeline events.

DESIGNING

This topic covers the aspects of the basic aerodynamics, fuel system, and the thermal protection system.

Requirements:

  1. Light-weight: There is a whole lot of sensors, types of equipment, satellites that lead to the very heavy weight of the whole system. The gross weight reaches to 4.4 Million pounds of a typical space shuttle system at launch.
  2. Structural integrity: The shuttle burns 1.99 Million kg of fuel in 8.5 minutes. Which pushes the shuttle from zero to 7850 m/s in orbit with an average acceleration of 29.4 m/s^2.
  3. Reusability: The economy is the major coin side that determines the fate of any technology. Making the space shuttle partially reusable was also a major challenge.
  4. Thermal protection: The temperature of the skin of space shuttle in its journey varies from -156 degrees in space to 1650 degree Celsius on re-entry.  Advanced thermal systems are required to keep the temperature of highly explosive cryogenic propellant under required temperature and also prevent crew inside to get singed from this extreme heat or get frostbite in space.

Basic components:

Image result for space shuttle illustration

So this is a typical space shuttle comprising of three basic units:

i) the orbiter, ii)the orange coloured external fuel tank(ET), iii) two solid- rocket boosters(SRBs).

Let us explore each element one by one and see what engineering challenges they presented and how it is fixed.

THE ORBITER:

SPACE SHUTTLES: The Ultimate Vehicles

This is the most significant part of the whole system. The reusable element of the space shuttle and that too up to 100 missions with minimal maintenance.

It is exposed to extreme temperature variations from -150 degrees Celcius in space when overlapped by earth’s shadow and 1600 degrees Celsius on re-entry. Moreover, it is supposed to produce massive accelerating forces by its own engines and thus requires high structural integrity to withstand those crushing forces on itself.

The most challenging part is an advanced reliable thermal protection system.

So, what’s the hack?

Like most of the time most complex problem is best addressed by the most simple solution, same is the case here.

So what is the best way to tackle heat?

The answer is INSULATION. Simply don’t allow the heat to enter the orbiter.

Engineers turned to simple silica sand to find an insulation material to operate at 1600 degrees. An ultralight highly porous block manufactured out of silica from sand which consists of 90% of air and rests10% special grade sand. These segments are called tiles. There are over 27,000 of these tiles on the shuttle of intricate shapes and design, all just as important as the next. Also, these tiles are not mechanically bolted on the body of shuttle instead glued with normal silicone adhesive on aluminium skull. In this way segmentation of tiles allowed for reusability by replacement of small damaged segments after every mission.

SPACE SHUTTLES: The Ultimate Vehicles

They are extremely good at heat dissipation. These tiles taken from a 2,300 oF oven can be immersed in cold water without damage. The surface dissipates heat so quickly that an uncoated tile can be held by its edges with an ungloved hand seconds after removal from the oven while its interior still glows red.

SPACE SHUTTLES: The Ultimate Vehicles

Also, the temperature is not distributed uniformly through the orbiter at re-entering. The base of craft sees much higher temperature compared to the top.Hence, different composition of tiles is used in different parts of the orbiter. The leading tips of wings experience the highest of all, touching the 3000 degrees Celcius mark. Thus they are specially made up of a composite material called reinforced carbon-carbon.

SPACE SHUTTLES: The Ultimate Vehicles

Probability of tile failure is not greater than 1/10 ^8. To accomplish this magnitude of system reliability and still minimize the weight didn’t come unpaid. It was only after the Columbia Shuttle disaster on 1 Feb 2003, investigations revealed the vulnerability of the ultralightweight tile to get punched by orbital debris. India lost its daughter Miss Kalpana Chawla in this disaster.

It was the aftermath of the unfortunate disaster that NASA pushed tougher to develop a highly secure and reliable heat shield, including the reinforced carbon-carbon composite for wing edge, which was the reason of melting of the shuttle on re-entry.

SPACE SHUTTLES: The Ultimate Vehicles
The STS-107 crew includes, from the left, Mission Specialist David Brown, Commander Rick Husband, Mission Specialists Laurel Clark, Kalpana Chawla and Michael Anderson, Pilot William McCool and Payload Specialist Ilan Ramon. (NASA photo) 

SPACE SHUTTLES: The Ultimate Vehicles

This shot focuses on the bottom of an orbiter named DISCOVERY.

These short video summaries neatly the concept of the thermal protection system (TPS) using the tiles.

 

If we talk about electrical power availability for the instrumentations and other important operations then it is supplied by three hydrogen-oxygen fuel cells which is operated by the cryogenic storage tanks installed on the orbiter. They are capable of generating 21 kW of power at 28 volt DC which is then converted to 115 V, 400 Hz, three-phase AC power for orbiter and payloads.

Amazingly the byproduct of the fuel cell is water which is made available for use for crew onboard.

Now comes the backbone of the space shuttle at the launch, the most massive part of this giant, the external fuel tank (ET).

THE EXTERNAL FUEL TANK:

SPACE SHUTTLES: The Ultimate Vehicles

This 50 m high and 8 m in diameter ET provide the fuel to three main engines and structural integrity at launch, hence is known as the backbone of the space shuttle.

  • The ET carries cryogenic propellants i.e. liquid oxygen and liquid hydrogen for the combustion in three main engines on orbiter in two separate compartments divided by an unpressurised intertank that holds all the electrical components for proper operation.
  •  An empty ET weighs around 35.5 Kilo Kg and it holds about 1.6 million pounds of propellants i.e a volume of about 2 million litres (enough to drive 1000 average cars round the year).
  • The ET supplies fuel to main engines on orbiter through two feed lines measuring 43 cm in diameter. The pressurised LO2 capable of flowing at a maximum rate of 66.6 thousand litres per min and LH2 at a max rate of 179 thousand litres per minute.
  • The ET is jettisoned after a burn time of around 510 seconds, after which it returns back to earth following a predetermined trajectory and lands in the remote ocean.

Physical structure:

  • The front chamber carries liquid oxygen at 250 kPa and at −182.8 °C in tank volume of 559.1 m3.
  • The intertank hoses all the operational instruments and also receive and distribute the thrusts from the SRBs.
  • The aft chamber carries liquid hydrogen at 300 kPa and −252.8 °C in 1,514.6 m3 tank volume.
  • Although hydrogen tank is 2.5 times larger than the oxygen tank but weighs only one-third as much when filled to capacity. The reason for the difference in weight is that liquid oxygen is 16 times heavier than liquid hydrogen.
  • Each fuel chamber also includes an internal slosh baffle and a vortex baffle to dampen fluid slosh due to vibrations.

SPACE SHUTTLES: The Ultimate Vehicles

Engineering challenge:

The thermal protection system is also critical for ET so as to maintain proper fuel temperature during the ascent of 8.5 minutes. Moreover, freezing ice at standby condition due to highly-chilled cryogenics on the skin of ET, which later form debris and impacts the orbiter glass shield or damages the tiles should be checked.

The ET is covered with a 1-inch (2.5 cm) thick layer of polyisocyanurate foam insulation, which also gives its distinguishing orange colour. The insulation keeps the fuels cold, protects the fuel from the heat that builds upon the ET skin in flight, and minimizes ice formation at standby.

The proper foam material selection only came after the loss of Columbia space shuttle in which insulating foam broke off the ET and damaged the left wing of the orbiter, which ultimately caused Columbia to break up upon re-entry.

SPACE SHUTTLES: The Ultimate Vehicles

This is a close view of the insulating foam on the ET.

THE SOLID ROCKET BOOSTERS:

These reusable boosters provide 70% thrust for liftoff of the space shuttle from the launch pad. They are 45 m high, 3.5 m  in diameter and weigh up to 1.3 million pounds. The solid propellant that fuel consists of atomized aluminium (16 %) (as fuel), ammonium perchlorate (70 %) (acts as oxidiser), iron oxide powder (0.2 %) (acts as catalyst),  polybutadiene acrylonitrile (12 percent) as curing agent and epoxy resin (2 percent).

SPACE SHUTTLES: The Ultimate Vehicles

They also bear the whole weight of shuttle on launch pads. With a burn time of 127 seconds, they are jettisoned and parachuted into the ocean and recovered by signalling devices and reused.

Not this element proved good to NASA and led to the disastrous crash of Challenger Shuttle,1986 due to a technical fault in the O-rings, killing all the crew on board.

SPACE SHUTTLES: The Ultimate Vehicles

The STS-51L crewmembers are: in the back row from left to right: Mission Specialist, Ellison S. Onizuka, Teacher in Space Participant Sharon Christa McAuliffe, Payload Specialist, Greg Jarvis and Mission Specialist, Judy Resnik. In the front row from left to right: Pilot Mike Smith, Commander, Dick Scobee and Mission Specialist, Ron McNair.

 

MISSION PROFILE:

 

LAUNCHING AND MANEUVERING

SPACE SHUTTLES: The Ultimate Vehicles

REENTRY AND LANDING

SPACE SHUTTLES: The Ultimate Vehicles

POST LANDING PROCESSES

SPACE SHUTTLES: The Ultimate Vehicles

BRIEF HISTORY

The credit of the science of space shuttle taking humans to space goes unravelled to NASA. The astronauts, scientist, and engineers who worked at NASA are entitled to standing ovations by the whole human society.

U.S started his visionary program called Space Transportation System (STS) and launched the first mission in the year 12 April 1981. The STS-1 named space shuttle Columbia successfully completed its orbital test flight. A fleet of 5 space shuttles named Challenger, Endeavor, Columbia, Discovery and Atlantis executed a total of 135 mission. Out of which two of them, Challenger (STS-51) and Columbia (STS- 107) failed that lead to loss of 14 crew members, rest other missions successfully scripted in pages of history. The space shuttle Atlantis (STS – 135) marked the last mission on 8 July 2011.

SPACE SHUTTLES: The Ultimate Vehicles

By the end of this mission, the world got the valuable gifts of ISS (International Space Station), Hubble Telescope, GPS technology, mobile communication, and many scientific experiments conducted in space. All of these technology forms the backbone of 21st-century human civilization and raises in us the hope of interplanetary successful human transportation someday!!!!

SPACE SHUTTLES: The Ultimate Vehicles

The biggest achievement of space missions: THE ISS

CONCLUSION

Humans might have used the science to attack enemy nation from space which could have possibly erased the existence of the whole planet, but fortunately, this marked the cradle for a  technology which has now become the indispensable part of our life.

So, being a modern engineering marvel, it also led to the end of the cold war between the giants US and Soviet Union, which otherwise could have wiped the planet after leading to third world war.

FOR READABILITY ISSUES “THE MISSION PROFILE” TOPIC WOULD BE COVERED IN NEXT BLOG. 

In the end, a beautiful clip to experience the thrill of space shuttle launch…

Thanks for your kind attention and valuable time!!!

Stay tuned for the next blog, till then your doubts and thoughts are most welcomed.

Keep reading, Keep learning!

TEAM CEV!!

CEV - Handout