in close orbit

Largest Batch of Earth-size, Habitable Zone Planets

Our Spitzer Space Telescope has revealed the first known system of seven Earth-size planets around a single star. Three of these planets are firmly located in an area called the habitable zone, where liquid water is most likely to exist on a rocky planet.

This exoplanet system is called TRAPPIST-1, named for The Transiting Planets and Planetesimals Small Telescope (TRAPPIST) in Chile. In May 2016, researchers using TRAPPIST announced they had discovered three planets in the system.

Assisted by several ground-based telescopes, Spitzer confirmed the existence of two of these planets and discovered five additional ones, increasing the number of known planets in the system to seven.

This is the FIRST time three terrestrial planets have been found in the habitable zone of a star, and this is the FIRST time we have been able to measure both the masses and the radius for habitable zone Earth-sized planets.

All of these seven planets could have liquid water, key to life as we know it, under the right atmospheric conditions, but the chances are highest with the three in the habitable zone.

At about 40 light-years (235 trillion miles) from Earth, the system of planets is relatively close to us, in the constellation Aquarius. Because they are located outside of our solar system, these planets are scientifically known as exoplanets. To clarify, exoplanets are planets outside our solar system that orbit a sun-like star.

In this animation, you can see the planets orbiting the star, with the green area representing the famous habitable zone, defined as the range of distance to the star for which an Earth-like planet is the most likely to harbor abundant liquid water on its surface. Planets e, f and g fall in the habitable zone of the star.

Using Spitzer data, the team precisely measured the sizes of the seven planets and developed first estimates of the masses of six of them. The mass of the seventh and farthest exoplanet has not yet been estimated.

For comparison…if our sun was the size of a basketball, the TRAPPIST-1 star would be the size of a golf ball.

Based on their densities, all of the TRAPPIST-1 planets are likely to be rocky. Further observations will not only help determine whether they are rich in water, but also possibly reveal whether any could have liquid water on their surfaces.

The sun at the center of this system is classified as an ultra-cool dwarf and is so cool that liquid water could survive on planets orbiting very close to it, closer than is possible on planets in our solar system. All seven of the TRAPPIST-1 planetary orbits are closer to their host star than Mercury is to our sun.

 The planets also are very close to each other. How close? Well, if a person was standing on one of the planet’s surface, they could gaze up and potentially see geological features or clouds of neighboring worlds, which would sometimes appear larger than the moon in Earth’s sky.

The planets may also be tidally-locked to their star, which means the same side of the planet is always facing the star, therefore each side is either perpetual day or night. This could mean they have weather patterns totally unlike those on Earth, such as strong wind blowing from the day side to the night side, and extreme temperature changes.

Because most TRAPPIST-1 planets are likely to be rocky, and they are very close to one another, scientists view the Galilean moons of Jupiter – lo, Europa, Callisto, Ganymede – as good comparisons in our solar system. All of these moons are also tidally locked to Jupiter. The TRAPPIST-1 star is only slightly wider than Jupiter, yet much warmer. 

How Did the Spitzer Space Telescope Detect this System?

Spitzer, an infrared telescope that trails Earth as it orbits the sun, was well-suited for studying TRAPPIST-1 because the star glows brightest in infrared light, whose wavelengths are longer than the eye can see. Spitzer is uniquely positioned in its orbit to observe enough crossing (aka transits) of the planets in front of the host star to reveal the complex architecture of the system. 

Every time a planet passes by, or transits, a star, it blocks out some light. Spitzer measured the dips in light and based on how big the dip, you can determine the size of the planet. The timing of the transits tells you how long it takes for the planet to orbit the star.

The TRAPPIST-1 system provides one of the best opportunities in the next decade to study the atmospheres around Earth-size planets. Spitzer, Hubble and Kepler will help astronomers plan for follow-up studies using our upcoming James Webb Space Telescope, launching in 2018. With much greater sensitivity, Webb will be able to detect the chemical fingerprints of water, methane, oxygen, ozone and other components of a planet’s atmosphere.

At 40 light-years away, humans won’t be visiting this system in person anytime soon…that said…this poster can help us imagine what it would be like: 

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

10

Cassini prepares for final orbital “Grand Finale” at Saturn.

Erik Wernquist, the same filmmaker who created 2014’s “Wanderers” and a stunning New Horizons promotional film in 2015, has created a new video highlighting NASA’s Cassini mission’s final days at Saturn.

The Cassini spacecraft will begin its final series of orbits to cap a 13-year groundbreaking science mission known as the Grand Finale. For the first time ever in Cassini’s time at Saturn, the spacecraft will fly in between the planet’s rings and atmosphere. No spacecraft has ever before flown in this region of any of the solar system’s ringed planets.

After 23 orbits, Cassini will dive into Saturn’s upper atmosphere September 15 where it will be destroyed. In 2008, mission managers explored a range of End of Mission scenarios that would protect Saturn’s moon’s from Earthly contaminants before ultimately deciding on atmospheric reentry.

Cassini began her End of Mission manoeuvres on November 26, 2016, when it began the first of 20 ring-grazing orbits. A close flyby of Titan April 22 will alter the spacecraft’s trajectory to begin the first of 23 orbits in the Grand Finale, which will begin April 26.

Cassini launched from Earth on October 15, 1997, and entered Saturn orbit June 30, 2004. Six months later, on January 14, 2005, the European-built Huygens probe attached to the spacecraft landed on Titan, becoming the first probe to land in the outer solar system. 

Originally scheduled for a four-year mission ending in 2008, Cassini received two mission extensions in 2008 and 2010, with the latter ending in 2017. With the spacecraft’s fuel reserves low, the Cassini team decided to end the mission.

P/C: JPL/Erik Wernquist

Seven Worlds for TRAPPIST 1 : Seven worlds orbit the ultracool dwarf star TRAPPIST-1, a mere 40 light-years away. In May 2016 astronomers using the Transiting Planets and Planetesimals Small Telescope announced the discovery of three planets in the TRAPPIST-1 system. Just announced, additional confirmations and discoveries by the Spitzer Space Telescope and supporting ESO ground-based telescopes have increased the number of known planets to seven. The TRAPPIST-1 planets are likely all rocky and similar in size to Earth, the largest treasure trove of terrestrial planets ever detected around a single star. Because they orbit very close to their faint, tiny star they could also have regions where surface temperatures allow for the presence of liquid water, a key ingredient for life. Their tantalizing proximity to Earth makes them prime candidates for future telescopic explorations of the atmospheres of potentially habitable planets. All seven worlds appear in this artists illustration, an imagined view from a fictionally powerful telescope near planet Earth. Planet sizes and relative positions are drawn to scale for the Spitzer observations. The systems inner planets are transiting their dim, red, nearly Jupiter-sized parent star. via NASA

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Some intriguing exoplanets

An exoplanet or extrasolar planet is a planet that orbits a star other than the Sun. The first scientific detection of an exoplanet was in 1988. However, the first confirmed detection came in 1992; since then, and as of 1 April 2017, there have been 3,607 exoplanets discovered in 2,701 planetary systems and 610 multiple planetary systems confirmed.

1- Kepler-186f

was the first rocky planet to be found within the habitable zone – the region around the host star where the temperature is right for liquid water. This planet is also very close in size to Earth. Even though we may not find out what’s going on at the surface of this planet anytime soon, it’s a strong reminder of why new technologies are being developed that will enable scientists to get a closer look at distant worlds.

2- CoRoT 7b

The first super-Earth identified as a rocky exoplanet, this planet proved that worlds like the Earth were indeed possible and that the search for potentially habitable worlds (rocky planets in the habitable zone) might be fruitful.

3- Kepler-22b  

A planet in the habitable zone and a possible water-world planet unlike any seen in our solar system.

4- Kepler 10-b

Kepler’s first rocky planet discovery is a scorched, Earth-size world that scientists believe may have a lava ocean on its surface.

5- 55 Cancri e

55 Cancri e is a toasty world that rushes around its star every 18 hours. It orbits so closely – about 25 times closer than Mercury is to our sun – that it is tidally locked with one face forever blisters under the heat of its sun. The planet is proposed to have a rocky core surrounded by a layer of water in a “supercritical” state, where it is both liquid and gas, and then the whole planet is thought to be topped by a blanket of steam.

6- 51 Pegasi b

This giant planet, which is about half the mass of Jupiter and orbits its star every four days, was the first confirmed exoplanet around a sun-like star, a discovery that launched a whole new field of exploration.

7- Kepler-444 system

The oldest known planetary system has five terrestrial-sized planets, all in orbital resonance. This weird group showed that solar systems have formed and lived in our galaxy for nearly its entire existence.

8- PSR B1257+12 system

Discovered in 1992 and 1994, the planets that orbit pulsar PSR B1257+12 are not only the smallest planetary bodies known to exist outside our solar system, they also orbit a neutron star. These weird “pulsar planets” demonstrated that planets exist in all environments in the galaxy – even around the remnants of an exploded star.

9- HD 80606 b  

This world has the most eccentric orbit, and as one scientist put it, “wears its heart on its sleeve,” with storms, rotation, atmospheric heating, and a crazy orbit all plainly visible.

10- OGLE-2005-BLG-390

Considered to be the first cold super Earth, this exoplanet began to form a Jupiter-like core of rock and ice, but couldn’t grow fast enough in size. Its final mass is five times that of Earth. The planet’s nickname is Hoth, after a planet from Star War

Credits: NASA / JPL-Caltech

lgbt+ book recommendations

I often see people talking about how they would like to read more lgbt+ books/series but do not know where to find them. SO I’ve made this list to give people somewhere to start !

PLEASE NOTE; I’ve written which stories are #ownvoices that I know of, some of them that I didn’t mention may be - sometimes it is hard to know, especially since it’s not something all authors write in bio’s ect. :) Please forgive and correct if you know some are #ownvoices that I have not mentioned. 

f/f

  • counting to zero - a.j quinn (#ownvoices)
  • everything leads to you - nina lacour
  • of fire and stars - audrey coulthurst
  • not your sidekick - c.b lee (poc)
  • the long way to a small, angry planet - becky chambers (#ownvoices)
  • a closed and common orbit - becky chambers (#ownvoices)
  • ice massacre - tiana warner
  • axiom: the last hope - marie rachel pearcy (#ownvoices)
  • get it together, delilah ! - erin gough
  • empress of the world - sara ryan
  • the upside down of unrequited - becky albertalli
  • girls man up - m-e girard
  • tell me again how a crush should feel - sara farizan
  • juliet takes a breath - gabby rivera

m/m

  • the foxhole court - nora sakavic (also poc)
  • the raven cycle - maggie stiefvater
  • six of crows duology - leigh bardugo (also poc)
  • aristotle and dante discover the secrets of the universe - benjamin alire saez (ft. poc characters) (#ownvoices)
  • will grayson, will grayson - john green and david levithan (semi #ownvoices)
  • we are the ants - shaun david hutchinson (#ownvoices)
  • the five stages of andrew brawley - shaun david hutchinson (#ownvoices)
  • the mortal instruments - cassandra clare (also bi rep, poc)
  • the dark artifices - cassandra clare (also bi rep)
  • the love interest - cale dietrich
  • captive prince series - c.s pacat
  • the song of achilles - medeline miller
  • whatever. or how junior year became totally fucked - s.j goslee
  • grasshopper jungle - andrew smith
  • ill give you the sun - jandy nelson
  • simon vs the homosapiens agenda - becky albertalli
  • carry on - rainbow rowell
  • boy meets boy - david levithan (#ownvoices)
  • two boys kissing - david levithan (#ownvoices)
  • the perks of being a wallflower - stephen chbosky
  • the gone series - michael grant (also, lesbian character. However, both side characters (though major ones), and not explored until later books. both poc )

trans

  • a kind of justice - renee james (#ownvoices)
  • if i was your girl - meredith russo (#ownvoices)
  • the art of being normal - lisa williamson
  • george - alex gino (#ownvoices)
  • every heart a doorway - seanan mcguire (asexual character)
  • coffee boy - austin chant
  • when the moon was ours - anna-marie mclemore 
  • roller girl - vanessa north (also f/f couple)

bi

  • adaptation - malinda lo (#ownvoices)
  • ash - malinda lo (#ownvoices)
  • radio silence - alice oseman

other lgbt:

  • magnus chase and the gods of asgard - rick riordan (genderfluid character)
  • every heart a doorway - seanan mcguire (asexual character)
  • the long way to a small, angry planet - becky chambers (gender fluid and non-binary characters - NOTE: this is a space opera and features aliens who are non-binary/gender fluid not humans. however, the main character who is human is lgbt - this is a very socially aware book and I recommend it even if it’s non-human characters) 

FINAL NOTE: I have not read all these books and cannot comment on the representation in all of them, but I have only included books I’ve heard good reception about. 

feel free to add on !! or check my READING LIST for more

GUIDE: HOW TO BE WHOLE AGAIN

1. take a gulp of interstellar gas
(taste the stars dancing on your tongue; feel the cosmic dust tickling your throat)

2. dip your toes into the cloud of particles hovering at your feet
(planets circle around your ankles; gravity is relative)

3. run your fingers through the inexhaustible space around you
(hold the darkness in your palms like it is a tangible thing; time is infinite)

4. let the galactic tide wash over you
(multitudes of celestial bodies fit against your body like puzzle pieces)

5. inhale;
(meteors rattle your lungs and paint luminous streaks along your ribs; new-born stars bloom from the trails of ice and dirt)

6. exhale;
(a globular cluster condenses just inches from your lips and whirls in interminable orbit; close your eyes and feel the solar flares kiss your lashes)

7. let the spiraling nebula swallow you whole
(constellations tangle in your hair and deconstruct along your cheeks; the galaxy unfolds against your skin)

— 

you are whole again

vade mecum series, pt.1

2

A ferry ride home and I’m officially on my staycation. One week of no commuting, no work, no classes, and no homework. I’m going to get so much done! And I might just overlook my entire TBR and current reading lists to start this pretty new release, a follow-up to The Long Way to a Small, Angry Planet.

A Closed and Common Orbit by Becky Chambers

goodqueenalys  asked:

yayyyy PROMPTS! could you maybe hit me with a little bellarke + people noticing/pointing out that they can't have a conversation or stand near each other without their noses basically touching?? thanks boo!

Special thanks to @thelovelylights who graciously helped me with some Spanish so that Raven felt more authentically Latinx. 

If you have something you’d like me to write you I have a ship list and I’m totally taking prompts

Orbit
rated teen for kissin’ 
[or read it on AO3]

The whole walk back to Arkadia takes longer than it needs to. But neither of them seem prepared to move away from each other. They walk so close that their knuckles brush and finally Bellamy hooks a long finger around hers. His skin his warm and Clarke finds herself curling her hand into his, leeching heat off his skin. Jaha glances over his shoulder at them periodically, favouring his arm against his side. Maybe checking to see that they’re still following at the slow steady pace which allows them to walk side by side, to match his long strides to her shorter ones.

Keep reading

just-some-writer  asked:

I have a world in my novel that being investigated for terraformation. It's a large moon (slightly smaller than Earth) orbiting a gas giant. It's tidal-locked to its planet. Would the planet-facing hemisphere have a different climate than the non-planet-facing hemisphere? I currently have it written that the outward-facing side is more temperate, while the other is much warmer. But that just struck me as a fun idea and I don't actually want to use it if it's weird or implausible. Thanks!

Note: the following is for the moon to support life-as-we-know-it (carbon-based, some type of DNA or analogue, etc). Silicon-based life or other exotic life could live in very different environs..

A habitable moon orbiting a gas giant (which we will call the primary) would require both the gas giant primary and the habitable moon to have certain characteristics.

For analysis, lets assume the primary is a Jupiter-sized gas giant. We’d have to move it closer to it’s star than Jupiter is in our system, so there would be enough heat from the star to keep the planet habitable. The additional heat from the primary will help so we don’t have to move it as close to the star as we otherwise might.

This would make your primary a ‘hot Jupiter’ - a gas giant that orbits close to it’s star. We know of a lot of hot Jupiters in nearby systems.

Having an Earth-sized moon isn’t a stretch at all. The second largest moon in our Solar system is Titan, a moon of Saturn. It has a radius of 2575 km, about half the size of the Earth. It also has an atmosphere - one made of nitrogen, methane, and hydrogen. Ick, but this shows that a large moon with an atmosphere is possible.

The biggest danger to your habitable moon is the primary’s magnetosphere. This is the magnetic field generated by the primary. Although this magnetic field will help shield your moon from cosmic rays and radiation from its star, it also traps a lot of radiation particles and keeps them close to the primary - like Earth’s Van Allen Belts but much, much bigger and powerful. On moons close to the primary, that’s enough radiation to kill everything. Jupiter’s inner moons are orbiting inside a giant microwave oven.

To have a life-bearing moon, we need to do one of two things to it - preferably both to be on the safe side: move the moon outside of the radiation belts of the magnetosphere and/or give the moon it’s own magnetic field.

As your moon is about Earth-sized, it probably has a rotating iron core. It’ll have a magnetic field, but lets place it outside the primary’s radiation danger zone just to make sure.

For Jupiter, the safe distance is about 1.5 million km. So, lets put your moon at the orbit of Callisto at 1.8 million km. At this distance, what little radiation your moon gets from the primary’s belts is blocked by the moon’s magnetic field.

Good call on the moon being tidally-locked to its primary. Jupiter’s and Saturn’s largest, closest moons are tidally-locked to their primaries (including Callisto). What this situation will do is make your moon’s day-night cycle quite a bit more interesting than just sunlight and darkness.

As the above mages shows, your moon will have a varying amounts of illumination - a time where only the star is visible (true day), a time where both star and primary is visible (brighter day), a time where the primary only is visible (false day), and a dark time where neither primary nor star is visible (true night). The moon will have a day length equal to the time it takes to orbit it’s primary.

Putting your moon at the same, safe distance as Callisto, it will orbit it’s primary in about 16.5 Earth days, so the moon’s ‘day’ will be just under 400 hours. If your moon orbits in the same plane that the primary’s orbit is in (and it probably does, cause that’s how most orbits work), you’ll have a short eclipse of the star by the primary every day for a couple of hours. Indeed, it’ll happen at local noon.

The tidal-locking of your moon probably wont have much of an effect on the planet’s environment. The side pointing towards the star will get really hot, seeing 200 hours of daylight, but it’ll cool off at night. The heat from the star will have much more impact than the heat form the primary. 

A good atmosphere and oceans (like Earth’s) will do a lot to spread the heat across the planet more evenly. It’ll probably have more extreme days and nights than Earth, but probably not enough to make living there too difficult.

Of course, the view from your moon would be spectacular. The primary will hang in the same spot in the sky looking about nine times the diameter of Earth’s full moon. It’ll be dozens of times brighter than the full moon, as well.

tl;dr:  Your setup is quite plausible and believable, and you’ve got the basics pretty good.. There is nothing known that would make such a setup implausible.

Hey, if it’s good enough for the Rebels…

7

Did Mars once have three moons?

“While the large Moon will be destined to be tidally destroyed and drawn to the surface through friction with Mars’ atmosphere, the other two moons could remain. Phobos and Deimos had a much larger sibling at some point in the past, but it may have lasted only for a few million years. After billions of years more, these two small moons remain. Perhaps in a few billion more, Phobos may be destroyed as well. If the new theory is right, a future scientist will only have Deimos and the basins on Mars to piece together this story from. It’s a stark reminder that in the Solar System and the Universe in general, the past is gone. All we have left to base its history on are the survivors.”

Compared to the other moons we know of in the Solar System, Mars’s two, Phobos and Deimos, are incredibly difficult to explain. They look like captured asteroids, being small, irregular, and exhibiting the right surface features. But captured asteroids form inclined or even retrograde orbits quite distant from their planet, while Phobos and Deimos live in circular, equatorial, close-in orbits to Mars. An alternative theory to the captured asteroid scenario is that the moons of Mars formed from a giant impact that kicked up a circumplanetary debris disk, similar to how Earth’s moon formed. But those scenarios never lead to merely two small moons; there’s always at least one large one. Thanks to a new simulation, all the pieces might finally be coming together.

Could Mars have had an inner, larger moon in the past that’s now decayed and collided back with the red planet? Get the story today!

I love someone who doesn’t love me.

I love someone who doesn’t know
the sound of my heart thump thump thumping
against his chest, doesn’t know it is
gutted like a peach without the seed,
swinging back and forth like a pendulum
and I am blocking out every source of
distraction, thinking solely of his name.

He doesn’t know how my lungs expand and
trap air while I hold my breath until I am
drowning in oxygen. He doesn’t know
that at night, I move my head as close
as I can get to his chest, trying desperately
to hear his voice like a lullaby, fastening
my fickle skull to the edge of my pillow.

I don’t believe in love at first sight, but
I believe in the science of gravitational pull,
like I am the Earth and he is the sun and
one day, I will orbit too close and shatter
into space. And like the sun, he will remain
big and bright and beautiful for years to come
and he will never belong to the Earth;
the Earth will always owe the sun.

I love someone who doesn’t love me,
someone who never learned not to bite
the hands that feed. And that’s what I do:
I feed him my love, break my own heart
as it bursts through the seams, fall in love
with sound of his fingers moving across
the piano, not realizing that it is
my organs he is pounding on.

Now I broadcast my love with words outlined
in a teleprompter: professional, closed off.
I am not afraid to love him.
But now, when he touches my palms,
I am no longer afraid to clasp my hands.

—  I love someone who doesn’t love me, but I won’t let it shrink my heart or own my life
Saturn V

The Saturn rocket series’ biggest brother, the culmination of America’s efforts during the Cold War Space Race against the Russians, and the paragon of human spaceflight achievement, The Apollo program’s primary tool was the mighty Saturn V, the pride of American space exploration, and NASA’s poster child. Designed by Wehrner von Braun, the massive rocket took 24 astronauts beyond Earth’s orbit, 12 of which walked on the Moon.

The Saturn V dwarfed every previous rocket fielded by America in the Space Race, remaining to this day the tallest, heaviest, and most powerful rocket ever brought to operational status and still holds records for the heaviest payload launched and largest payload capacity. On the pad, she stood 363 feet (111m) tall, taller than the Statue of Liberty by 58 feet, with a diameter of 33 feet (10m), and weighed 6.5 million pounds fully fueled. Her designed payload capacity was rated at 261,000 pounds (118,000 kg) to Low Earth Orbit and 90,000 pounds (41,000 kg) to the Moon, but in later missions was able to carry about 310,000 pounds (140,000 kg) to LEO and sent up to 107,100 lb (48,600 kg) worth of spacecraft to the Moon.

The total launch vehicle was a 3 stage vehicle: the S-IC first stage, S-II second stage and the S-IVB third stage. The first stage used RP-1 for fuel, while the second and third stages used liquid hydrogen (LH2), with all three using liquid oxygen (LOX) for oxidizer.

Originally posted by spaceplasma

First Stage

The first stage of the Saturn V is the lower section of the rocket, producing the most thrust in order to get the vehicle off the pad and up to altitude for the second stage.

The Rocketdyne F-1 engine used to propel the rocket was designed for the U.S. Air Force by Rocketdyne for use on ICBM’s, but was dropped and picked up by NASA for use on their rockets. This engine still is the most powerful single combustion chamber engine ever produced, producing 1,522,000 lbf (6,770 kN) at sea level and 1,746,000 lbf (7,770 kN) in a vacuum. The S-IC has five F-1 engines. Total thrust on the pad, once fully throttled, was well over 7,600,000 lbf, consuming the RP-1 fuel and LOX oxidizer at a jaw-dropping 13 metric tonnes per second.

The launch sequence for the first stage begins at approx. T-minus 8.9 seconds, when the five F-1 engines are ignited to achieve full throttle on t-minus 0.  The center engine ignited first, followed by opposing outboard pairs at 300-millisecond intervals to reduce the structural loads on the rocket. When thrust had been confirmed by the onboard computers, the rocket was “soft-released” in two stages: first, the hold-down arms released the rocket, and second, as the rocket began to accelerate upwards, it was slowed by tapered metal pins pulled through dies for half a second.

It took about 12 seconds for the rocket to clear the tower. During this time, it yawed 1.25 degrees away from the tower to ensure adequate clearance despite adverse winds. (This yaw, although small, can be seen in launch photos taken from the east or west.) At an altitude of 430 feet (130 m) the rocket rolled to the correct flight azimuth and then gradually pitched down until 38 seconds after second stage ignition. This pitch program was set according to the prevailing winds during the launch month. The four outboard engines also tilted toward the outside so that in the event of a premature outboard engine shutdown the remaining engines would thrust through the rocket’s center of gravity. At this point in the launch, forces exerted on the astronauts is about 1.25 g.

At about T+ 1 minute, the rocket has gone supersonic, at which point, shock collars form around the rocket’s second stage separator. At this point, the vehicle is between 3 and 4 nautical miles in altitude.

Originally posted by sagansense

As the rocket ascends into thinner atmosphere and continues to burn fuel, the rocket becomes lighter, and the engine efficiency increases, accelerating the rocket at a tremendous rate.  At about 80 seconds, the rocket experienced maximum dynamic pressure. Once maximum efficiency of the F-1 engines is achieved, the total thrust peaks at around 9,000,000 lbf. At T+ 135 seconds, astronaut strain has increased to a constant 4 g’s.

At around T+ 168 seconds, the engines cut off as all fuel in the first stage is expended. At this point in flight, the rocket is  at an altitude of about 36 nautical miles (67 km), was downrange about 50 nautical miles (93 km), and was moving about 6,164 miles per hour (2,756 m/s). The first stage separates at a little less than 1 second following engine cutoff to allow for engine trail-off.  Eight small solid fuel separation motors backs the S-IC from the rest of the vehicle, and the first stage continues ballistically to an altitude of about 59 nautical miles (109 km) and then falls in the Atlantic Ocean about 300 nautical miles (560 km) downrange. Contrary to the common misconception, the S-IC stage never leaves Earth’s atmosphere, making it, technically, an aircraft.

Second Stage

The second stage is responsible with propelling the vehicle to orbital altitude and velocity. Already up to speed and altitude, the second stage doesn’t require as much Delta-V to achieve it’s operation.

For the first two unmanned launches, eight solid-fuel ullage motors ignited for four seconds to give positive acceleration to the S-II stage, followed by start of the five Rocketdyne J-2 engines. For the first seven manned Apollo missions only four ullage motors were used on the S-II, and they were eliminated completely for the final four launches. 

About 30 seconds after first stage separation, the interstage ring dropped from the second stage. This was done with an inertially fixed attitude so that the interstage, only 1 meter from the outboard J-2 engines, would fall cleanly without contacting them. Shortly after interstage separation the Launch Escape System was also jettisoned.

About 38 seconds after the second stage ignition the Saturn V switched from a preprogrammed trajectory to a “closed loop” or Iterative Guidance Mode. The Instrument Unit now computed in real time the most fuel-efficient trajectory toward its target orbit. If the Instrument Unit failed, the crew could switch control of the Saturn to the Command Module’s computer, take manual control, or abort the flight.

About 90 seconds before the second stage cutoff, the center engine shut down to reduce longitudinal pogo oscillations (a forward/backward oscillation caused by the unstable combustion of propellant). At around this time, the LOX flow rate decreases, changing the mix ratio of the two propellants, ensuring that there would be as little propellant as possible left in the tanks at the end of second stage flight. This was done at a predetermined Delta-V.

 Five level sensors in the bottom of each S-II propellant tank are armed during S-II flight, allowing any two to trigger S-II cutoff and staging when they were uncovered. One second after the second stage cut off it separates and several seconds later the third stage ignited. Solid fuel retro-rockets mounted on the interstage at the top of the S-II fires to back it away from the S-IVB. The S-II impacts about 2,300 nautical miles (4,200 km) from the launch site.

The S-II would burn for 6 minutes to propel the vehicle to 109 miles (175km) and 15,647 mph, close to orbital velocity.

Third Stage

Now in space, the third stage, the S-IVB’s sole purpose is to prepare and push the Command, Service, and Lunar Modules to the Moon via TLI. 

Unlike the two-plane separation of the S-IC and S-II, the S-II and S-IVB stages separated with a single step. Although it was constructed as part of the third stage, the interstage remained attached to the second stage.

During Apollo 11, a typical lunar mission, the third stage burned for about 2.5 minutes until first cutoff at 11 minutes 40 seconds. At this point it was 1,430 nautical miles (2,650 km)  downrange and in a parking orbit at an altitude of 103.2 nautical miles (191.1 km)  and velocity of 17,432 mph (7,793 m/s). The third stage remained attached to the spacecraft while it orbited the Earth one and a half times while astronauts and mission controllers prepared for translunar injection.

This parking orbit is quite low, and would eventually succumb to aerodynamic drag if maintained, but on lunar missions, this can be gotten away with because the vehicle is not intended to stay in said orbit for long. The S-IVB also continued to thrust at a low level by venting gaseous hydrogen, to keep propellants settled in their tanks and prevent gaseous cavities from forming in propellant feed lines. This venting also maintained safe pressures as liquid hydrogen boiled off in the fuel tank. This venting thrust easily exceeded aerodynamic drag.

On Apollo 11, TLI came at 2 hours and 44 minutes after launch. The S-IVB burned for almost six minutes giving the spacecraft a velocity close to the Earth’s escape velocity of 25,053 mph (11,200 m/s). This gave an energy-efficient transfer to lunar orbit, with the Moon helping to capture the spacecraft with a minimum of CSM fuel consumption.

After the TLI, the Saturn V has fullfilled its purpose of getting the Apollo crew and modules on their way to the Moon. At around 40 minutes after TLI, the Command Service module (the conjoined Command module and Service Module) separate from the LM adapter, turns 180 degrees, and docks with the exposed Lunar Module. After 50 minutes, the 3 modules separate from the spent S-IVC, in a process known as Transposition, docking and extraction

Of course, if the S-IVC were to remain on the same course (in other words, if they leave it right there unattended), due to the physics of zero gravity environments, the third stage would present a collision hazard for the Apollo modules. To prevent this, its remaining propellants were vented and the auxiliary propulsion system fired to move it away. Before Apollo 13, the S-IVB was directed to slingshot around the Moon into a solar orbit, but from 13 onward, the S-IVB was directed to actually impact the Moon. The reason for this was for existing probes to register the impacts on their seismic sensors, giving valuable data on the internals and structure of the Moon.

Launch Escape System

The Saturn V carries a frightening amount of potential energy (the Saturn V on the pad, if launch failed and the rocket ruptured and exploded, would have released an energy equivalent to 2 kilotons of TNT, a force shy of the smallest atomic weapons), which luckily was unleashed as planned without incident. However, this being NASA, precautions were made to save the crew in event of a catastrophic failure. 

The LES (Launch Escape System) has been around since the Mercury Program as a way to get the crew capsule away from a potential explosion on the pad or in early launch. The idea is that a small rocket would take the capsule far enough away from the rocket that parachutes could be deployed.

The LES included three wires that ran down the exterior of the launch vehicle. If the signals from any two of the wires were lost, the LES would activate automatically. Alternatively, the Commander could activate the system manually using one of two translation controller handles, which were switched to a special abort mode for launch. When activated, the LES would fire a solid fuel escape rocket, and open a canard system to direct the Command Module away from, and off the path of, a launch vehicle in trouble. The LES would then jettison and the Command Module would land with its parachute recovery system.

If the emergency happened on the launch pad, the LES would lift the Command Module to a sufficient height to allow the recovery parachutes to deploy safely before coming in contact with the ground.

An interesting factoid is how much power the LES possesses; in fact, the LES rocket produces more thrust (147,000 pounds-force (650 kN) sea level thrust) than the Mercury-Redstone rocket (78,000 pounds-force (350 kN)) used to launch Freedom-7 during the Mercury program. 

Skylab 

Originally posted by pappubahry

After budget cuts necessitated mission cancellations and the end of the Apollo program, NASA still had at least one Saturn V rocket intended for Apollo 18/19. Luckily, in 1965, the Apollo Applications Program was established to find a use for the Saturn V rocket following the Apollo program. Much of the research conducted in this program revolved around sending up a space station. This station (now known as Skylab) would be built on the ground from a surplus Saturn IB second stage and launched on the first two live stages of a Saturn V. 

The only significant changes to the Saturn V from the Apollo configurations involved some modification to the S-II to act as the terminal stage for inserting the Skylab payload into Earth orbit, and to vent excess propellant after engine cutoff so the spent stage would not rupture in orbit. The S-II remained in orbit for almost two years, and made an uncontrolled re-entry on January 11, 1975. 

This would be NASA’s only Saturn V launch not associated with the Apollo program, and unfortunately, would prove to be the Saturn V’s last one. There were other concepts for Saturn V’s as launch vehicles, including a space shuttle design, but none of these ever came to fruition. 

Cost

From 1964 until 1973, a total of $6.417 billion ($41.4 billion in 2016) was appropriated for the Saturn V, with the maximum being in 1966 with $1.2 billion ($8.75 billion in 2016). 

Displays and Survivors

There are several displays of Saturn V rockets around the United States, including a few test rockets and unused ones intended for flight. The list below details what and where they are.

  • Two at the U.S. Space & Rocket Center in Huntsville:

SA-500D is on horizontal display made up of S-IC-D, S-II-F/D and S-IVB-D. These were all test stages not meant for flight. This vehicle was displayed outdoors from 1969 to 2007, was restored, and is now displayed in the Davidson Center for Space Exploration. The second display here is a vertical display (replica) built in 1999 located in an adjacent area.

  • One at the Johnson Space Center made up of first stage from SA-514, the second stage from SA-515 and the third stage from SA-513 (replaced for flight by the Skylab workshop). With stages arriving between 1977 and 1979, this was displayed in the open until its 2005 restoration when a structure was built around it for protection. This is the only display Saturn consisting entirely of stages intended to be launched.
  • One at the Kennedy Space Center Visitor Complex, made up of S-IC-T (test stage) and the second and third stages from SA-514. It was displayed outdoors for decades, then in 1996 was enclosed for protection from the elements in the Apollo/Saturn V Center.
  • The S-IC stage from SA-515 is on display at the Michoud Assembly Facility in New Orleans, Louisiana.
  • The S-IVB stage from SA-515 was converted for use as a backup for Skylab, and is on display at the National Air and Space Museum in Washington, D.C.

Source: Wikipedia

If the planets had enneagram types...

An enneagram typing oddessy beginning at the center of our Solar System

Mercury: Type 6

6s stick close to the people, values, behaviors, and beliefs they deem safe and secure. I guess Mercury REALLY trusts the sun, as it has a tight, almost clingy orbit to our solar system’s only star.

Venus: Type 1

Just like type 1s strive for perfection of thought, actions and morals, Venus is just as hard on itself. Its thick atmosphere of Carbon Dioxide traps heat into a negative feedback loop, creating an insanely hot surface with intense atmospheric pressure. Similarly, 1s are no strangers to self-inflicted pressure that does nothing but make conditions difficult for life. 

Earth: Type 4

Just as 4s desire to see themselves as unique, Earthlings have seen themselves as the special snowflakes of the universe for millennia. It wasn’t until recently that the people of Earth didn’t think the universe revolved around THEM. Sigh.

Mars: Type 5

We’ve been fascinated by Mars for centuries, and type 5s are thirsty for knowledge. Though it seems like we’re learning more every day, these answers only lead to more and more questions. Sounds like a job for a type 5.  

Jupiter: Type 8

Like 8s, Jupiter is the big man of the solar system, with massive gravity that refuses to submit to anyone but the sun. Ain’t nobody gunna control Jupiter.

Saturn: Type 2

Just as 2s would be nothing without people to need them, Saturn wouldn’t be Saturn without its rings. 2s are their most comfortable when keeping their friends and loved ones in close orbit. 

Uranus: Type 3

Uranus’s gigantic size, oddly tilted rings, and awkward name all scream “look at me”, mirroring the desire for success and recognition that 3s crave.  

Neptune: Type 7

7s will travel as far out as Neptune, the furthest planet away from the sun, in order to avoid their problems.  Plus, despite Neptune’s massive size, it only takes 18 hours to make a full rotation. Sounds like a hyperactive 7 to me. 

Pluto: Type 9

Ah, Pluto, the lost planet of the solar system. Like the type 9, Pluto is shrouded in ambiguity, drifting dreamily in an elliptical orbit at the edge of the solar system. Clearly it’s conflict avoidant like 9s, since I don’t remember it vocally protesting when it was demoted from its status as a “planet”. 

I feel like we’ve gotta be in pretty close orbit to a parallel world where Clinton won the election, the Falcons won the super bowl, Beyonce won best album, and moonlight won best picture. The question is how do we get there?

What is a Exoplanet?

Exoplanets are the planets orbiting around stars other than our Sun. There are 2000+ confirmed exoplanets found in the known Universe. According to astronomers there can be trillions of exoplanets in our Galaxy.

Following are some amazing facts about exoplanets:

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