Category: space exploration

Everyone Missed An Apollo 11 Mistake, And It Almost Killed The Astronauts Returning To Earth

“Fortunately for everyone, they did get lucky. During the technical debriefing in the aftermath of Apollo 11, the fly-by of the Service Module past the Command Module was noted by Buzz Aldrin, who also reported on the Service Module’s rotation, which was far in excess of the design parameters. Engineer Gary Johnson hand-drew schematics for rewiring the Apollo Service Module’s jettison controller, and the changes were made just after the next flight: Apollo 12.

Those first four crewed trips to the Moon — Apollo 8, 10, 11 and 12 — could have all ended in potential disaster. If the Service Module had collided with the Command Module, a re-entry disaster similar to Space Shuttle Columbia could have occurred just as the USA was taking the conclusive steps of the Space Race.”

The flight plan for Apollo 11 was straightforward, if not quite simple. Follow the same trajectory to the Moon that Apollo 8 and Apollo 10 undertook, then successfully enter lunar orbit, launch the Lunar Module, descend to the surface and land softly, perform the scheduled EVA, then ascend back to the Command and Service Module, return to Earth, jettison the Service Module, re-enter, and deploy the parachute to successfully splash down in the Pacific Ocean. Only uncovered well after the mission, there was a huge flaw: the Service Module wasn’t programmed to jettison properly! If things had gone differently, the Command Module could have been damaged, and would have burned up in the atmosphere, killing all on board. 

Come learn about the Apollo 11 mistake that Armstrong, Aldrin, and Collins were lucky to survive!

Our Generation Is Not Getting A Moonshot, And This Is The Reason Why

“We could take equally bold steps today if we wanted to. There are literally thousands upon thousands of astronomers, physicists, engineers, technicians, computer scientists, hardware designers, rocket builders, habitat designers, and many other skilled professionals who would love to participate in a moonshot for a new generation: a generation that grew up where crewed spaceflight beyond low-Earth orbit was only a historical memory.

Instead of investing a substantial amount of resources in truly reaching towards new frontiers, we’re delegating them to uncrewed, robotic space probes. Sure, the amount of scientific information we can get out of them is much higher for a much lower cost, but getting the most bang-for-our-buck isn’t why we push the frontiers of knowledge. Instead, we’re taking baby steps where great strides are called for.”

Have you ever dreamed of traveling to another world? Even if you yourself aren’t game for the journey, have you dreamed of humanity achieving that goal? For most of us alive today, we have never lived during a time where human beings were present anyplace beyond low-Earth orbit. Unless something dramatically changes, that will likely remain true for the remainder of the century. Humans aren’t headed to the Moon, to Mars, to a satellite world in the outer Solar System, or to an interstellar destination unless we seriously take the initiative to re-invest in basic research and development. Until we start stably allocating resources, personnel, and R&D priorities towards these ends, we’re going to remain stuck here on Earth. 

Read this if you want to get motivated towards changing the course of human civilization for the better.

This Is How Mastering Dark Matter Could Take Us To The Stars

“Because dark matter is everywhere, we wouldn’t even need to carry it with us as we traversed the Universe. As far as we understand it — and admittedly, we need to understand it a lot farther — dark matter could truly deliver our dream of the ultimate fuel. It’s abundant all throughout our galaxy and beyond; it should have a non-zero annihilation cross-section with itself; and when it does annihilate, it should produce energy with 100% efficiency.

Perhaps, then, most of us have been thinking about experiments seeking to directly detect dark matter all wrong. Yes, we want to know what makes up the Universe, and what the physical properties of its various abundant components truly are. But there’s a science-fiction dream that could come true if nature is kind to us: unlimited, free energy just waiting there for us to harness, no matter where in the galaxy we go.

Mastering dark matter is the endeavor that just might make it so.”

When we talk about our dreams of traveling to the stars, it normally involves a mythical, futuristic form of travel that goes beyond the known laws of physics. Why’s that? Because even if you increase the efficiency of your rocket fuel far beyond the limitations of any chemical-based reaction we know of, you’d still be limited in how far you could go by the mass of your spacecraft and the fuel you were able to take with you on board. You’d still have to accelerate (and decelerate) all the fuel you brought with you, until you ran out. If only there were a 100%-efficient fuel source that was ubiquitous all throughout the galaxy and beyond. 

There is: dark matter. Here’s why it’s so important to study, understand, and eventually, fulfill the dream of harnessing it!

ICYMI we have been talking about Earth’s rotation for the past week on FYP!

We started off by asking the simple question: ‘Why did the Earth start spinning in the first place?

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And how has this rotation been affected by the moon over the course of centuries.

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But this did not give us any understanding for why the axis of rotation is inclined  by 23.5 degrees.

This is where we were introduced to the The Giant Impact Hypothesis which suggested that the Moon formed out of the debris left over from a collision between Earth and an astronomical body the size of Mars, approximately 4.5 billion years ago

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Now one of the consequences of living on a rotating object is that it flattens at its poles. The name given to such a flattened object is an oblate spheroid. We understood this using a simple experimental setup:

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Leaving all that aside, it was strongly believed by people for a really long time that it were the heavens that moved and not the earth.

It took a lot of debate among philosophers to come to the conclusion that it was indeed the Earth that was rotating. We looked at one such remarkable argument given by Galileo

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Having made this journey so far, we finally discussed how humans found a way to utilize the fact that we are on a rotating oblate spheroid to quench our thirst for the ecstatic understanding of the unknown.

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fuckyeahphysica:

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Last week we were talking about wind patterns and how they affect flight time. But it is also worth mentioning that Space shuttles are launched almost at all times from West to East to take advantage of the earth’s rotation


How does earth’s rotation affect shuttles ?

Earth is a spherical body rotating with some angular velocity. And as a result of this, the equator is rotating at a higher velocity than the poles. By launching a space shuttle from the equator you are getting a ‘speed boost’.  

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This means that if a shuttle is launched from the pole, it has to accelerate from 0 to 17000mph to reach orbital velocity.

But if a shuttle is launched from the equator, it only needs to accelerate from 1025 to 17000mph. (that 1025mph initial velocity is given by the earth free of charge)

This saves valuable amount of fuel required for propulsion

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Polar Orbits

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Not all rockets are launched from the west to east and the direction is determined by the purpose of its payload.

The satellites that are used for mapping for instance follow a Polar Orbit i.e they move from north to south or vice versa and therefore during launch they cannot take advantage of the earth’s rotation.

Florida or California

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Another characteristic of launching satellites is that the launching
stations are generally located near the coast just in
case of failure of the launch, the satellite falls in an uninhabited area.

NASA primarily uses Kennedy Space Center, Florida for east-west launches and Vandenberg Base California for polar orbits for the very same reason. ***

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Rocket science is just truly breathtaking.

* How fast are YOU spinning on Earth’s axis right now?

** Also check out about Retrograde motion

*** This statement holds true for most launches.

Previous post: The shape of the Earth is an oblate spheroid: A visual demo

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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 barrel.

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

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

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

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

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(e) Speed of cannonball – Crazy

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Gunpowders are not that powerful !

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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.

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

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Although this is not by any means a comprehensive post on this topic, but hopefully this gives you a sense of the physics that underlies it.

Have a good one!

** TRY IT OUT – Newton’s Cannon 

34 years ago, on this day NASA Astronauts performed the first untethered spacewalk. And yesterday Spacex just put a Tesla Roadster in an orbit to Mars. This is truly an exciting time to be alive.

** Just to be really clear, this is not the first time we are launching “automobiles” to space.

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                                        Lunar Roving Vehicle

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Behold the Dyson Sphere

Dyson sphere is a hypothetical mega-structure that completely encompasses a star and captures most or all of its power output.

Over the years many variants have been explored:

The simplest such arrangement is the Dyson ring, in which all ‘energy harvesting structures’ share the same orbit.

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Add multiple Dyson ring structures and you will get a Dyson swarm.

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Now what if you didn’t like a consistent orbit for your structures, you could employ a solar sail to continuously modify its orbit( called a statite ).

Such an arrangement would be known as a Dyson Bubble

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Then there is the fictionally popular version – The Dyson Shell, where a uniform solid shell of matter just encapsulates the entire star.

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And many many more. But you get the gist.

Could there be Dyson Spheres out there?

When scientists were monitoring the brightness from some stars, they
found that it fluctuated in some odd ways like so:

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                          Brightness v/s time for KIC 8462852

It is common for such dips to occur since when a planet eclipses a star, there would a drop in the brightness observed from the star.

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                       Brightness v/s time for a binary star system

But what was inconsistent is the duration and period of occurrence of these dips.

Although the main line of rationale remains as asteroid impact remnants or interstellar collisions causing these aberrations in data.

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But to say that these could the signs of an alien civilization does remain to be the more entertaining interpretation.

Great Question. Thanks for asking !

** For more information. check out this TED talk

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Last week we were talking about wind patterns and how they affect flight time. But it is also worth mentioning that Space shuttles are launched almost at all times from West to East to take advantage of the earth’s rotation


How does earth’s rotation affect shuttles ?

Earth is a spherical body rotating with some angular velocity. And as a result of this, the equator is rotating at a higher velocity than the poles. By launching a space shuttle from the equator you are getting a ‘speed boost’.  

image

This means that if a shuttle is launched from the pole, it has to accelerate from 0 to 17000mph to reach orbital velocity.

But if a shuttle is launched from the equator, it only needs to accelerate from 1025 to 17000mph. (that 1025mph initial velocity is given by the earth free of charge)

This saves valuable amount of fuel required for propulsion

image

Polar Orbits

image

Not all rockets are launched from the west to east and the direction is determined by the purpose of its payload.

The satellites that are used for mapping for instance follow a Polar Orbit i.e they move from north to south or vice versa and therefore during launch they cannot take advantage of the earth’s rotation.

Florida or California

image

Another characteristic of launching satellites is that the launching
stations are generally located near the coast just in
case of failure of the launch, the satellite falls in an uninhabited area.

NASA primarily uses Kennedy Space Center, Florida for east-west launches and Vandenberg Base California for polar orbits for the very same reason. ***

image

Rocket science is just truly breathtaking.

* How fast are YOU spinning on Earth’s axis right now?

** Also check out about Retrograde motion

*** This statement holds true for most launches.

‘If moon was just any place‘