Hephaestus's Blog


A Different Kind of Space Elevator
August 27, 2015, 07:04
Filed under: Space stuff

In my space elevator post last Thursday, I mentioned a different kind of ‘space elevator’ patented by Thoth Technology Inc. This is an intriguing concept, and I thought I would share it.

While a normal space elevator is a tensile structure reaching out past geostationary orbit, the concept by Thoth is rather… different.

Their idea is a 20 km-tall tower, “pneumatically pressurized” (inflatable), with elevators inside. On the top of the tower would be, essentially, a spaceport, from which spaceplanes could launch, thus beginning their journey above the thickest parts of the atmosphere.

According to Thoth Technology’s website, the tower could also be used for wind power generation and tourism (the latter presumably via some sort of observation deck).

While this tower would probably be quite the undertaking to build, not to mention becoming by far the tallest structure in the world, mind-bogglingly high by any measure save that of space elevators, it would still be many times easier to build than a bona fide Tsiolkovsky-Artsutanov space elevator.

Advertisements


Why Terra Needs a Space Elevator
August 20, 2015, 09:32
Filed under: Space stuff

First of all, we need to know: What exactly is a space elevator?

At its heart, a space elevator is a very long tether, running from the surface of Earth to a counterweight placed in Geostationary orbit.

Compared to other forms of space launch, such as rockets, the space elevator is a remarkably economic, if nearly impossible and prohibitively difficult to build, solution to the great challenge: Getting what’s down here up there.

Now why we need it.

Spaceflight is expensive. The cheapest (and also really small) launch vehicles still cost thousands of dollars per kilogram of cargo. As you can imagine, this puts the cost of placing anything larger than a loaf of bread into orbit out of reach of all but governments, institutions, and large corporations like SES or Boeing.

A space elevator is perhaps the only way of bringing the price of an orbital jaunt within the reach of the general public, or making possible voyages to space on a large scale; even a re-usable rocket vehicle, such as that being developed by SpaceX, will only cut the price to about one-third to one-sixth of the current figure.*

But there’s more. Rocketry is, by its very nature, a fast, dangerous and somewhat tenuous way of getting anywhere; if you can, it’s probably better to walk. A space elevator would have this crucial difference from rocket travel: it would automatically be 1) a permanent fixture on the planet, unable to move significantly, and 2) a slower, safer, more comfortable ride. (This applies to cargo as well: imagine if satellites didn’t have to be designed to take prodigious acceleration and vibration).

Although it may seem hard to believe, there are several groups dedicated to creating a space elevator. Among these are the International Space Elevator Consortium and LiftPort Group (who want to build one on the Moon).

Additionally, a company called Thoth Technology recently patented a very different kind of “space elevator”, an inflatable tower and launch platform, but that is beyond the scope of the current post.

In closing, a hypothetical space elevator would probably be a cheaper, safer and more reliable way of reaching space than any we have today. Good luck to the daring and maybe crazy engineers trying to make it happen in our lifetimes.

*These are all estimates; exact numbers on this kind of thing are extremely hard to find.



Space and Sea Voyages: a Comparison
March 26, 2015, 16:09
Filed under: Space stuff

It has recently occurred to me that a long-term space voyage, such as to Mars, would have a lot in common with the sailing voyages, especially those undertaken by the oceanic explorers of the age of sail. I note that there are at least three distinct threads of similarity, and will go over each of them in turn. They are the duration of the voyage, the sources of financial backing, and the risks to the crew.

 

First, the duration. A Martian voyage, using a standard Hohmann transfer orbit, would take on the order of 400-500 Earth days. On the other hand, each of Captain Cook’s three Pacific voyages lasted roughly three years, considerably longer than a Mars flight.

Of course, Captain Cook’s ship was probably never more than a few months between landfalls. However, a modern Mars mission, although the astronauts would be in considerably smaller quarters than eighteenth-century sailing ships, would only be confined to their ship during the interplanetary cruise of about 180-200 days. In addition, with modern methods of communication, they would have more often and more reliable correspondence than any sailor.

 

Second, financial backing. Cook’s voyages, as well as those of Magellan et al., were made with the funds and backing of national governments. In the case of Cook’s first voyage, the mission was to observe the transit of Venus and search for an undiscovered Terra Australis. This was supported by the Royal Society and King George III.

Similarly, the earliest explorations of outer space were funded by national space agencies. However, as time goes on, there may be more and more space voyages being undertaken using private capital. A seafaring parallel to this can be found in the whaling voyages of the nineteenth century, which often went all around the globe.

 

Third, the risks. Prior to the discovery that vitamin C prevents scurvy, many sailors died of this horrible ailment. Even after that, death was often caused by the various infectious diseases of the tropics, to say nothing of the risk of death by accident.

In space, while scurvy is unlikely and infectious disease impossible, the risk of illness of other kinds is by no means entirely banished. Radiation is a serious concern, and, of course, microgravity brings with it all kinds of potential problems, from osteoporosis to eye defects. Accidents, as any of us older than fourteen know well, are a very real presence in spaceflight, just as they were in the age of sail. Having a hard vacuum (or Martian “atmosphere”) just outside the walls of your spacecraft puts you in constant danger due to leaks, power failures and so on, and launch and atmospheric entry have killed many more than space exposure.

 

In closing, there are many parallels between a sailing voyage and a space one, even if there are many differences between their respective destinations. I suppose a trip is a trip, no matter where you’re going.



My Favorite Isaac Asimov Stories
January 5, 2015, 19:25
Filed under: Space stuff

Last Saturday (the 2nd) would have been Isaac Asimov’s 95th birthday*. In honor of this, I present:

My Five Favorite Asimovs

 

Foundation(1951)

This novel introduced the Galactic Empire** trope. The Foundation trilogy, including Foundation and Empire and Second Foundation, was expanded with four more Asimov novels and three by other authors.

Runaround(1942)

This story, included in the famous anthology/novel*** I, Robot, was the first appearance of Asimov’s famous Three Laws of Robotics.

The Red Queen’s Race(1949)

This one has a very interesting, if not entirely original, stance on time travel. I thoroughly enjoyed it.

Profession(1957)

An interesting story about creativity and originality.

Take a Match(1972)

A story set on a spaceship in an all-fusion time.

 

*Asimov’s actual date of birth is uncertain, but he celebrated it on January 2nd, so I think we may as well go with that.

** I do not capitalize “Galactic Empire” as one unit, but as two: “Galactic”, referring to the Galaxy, and “Empire”. Each word merits capitalization on its own.

*** I, Robot is a collection of previously published stories, with material added to connect them into one narrative of Susan Calvin’s career.



SpaceX Haiku
May 28, 2014, 13:14
Filed under: Poetry, Space stuff

Here are some haiku about commercial space transportation company SpaceX. The subject of each is something to do with SpaceX, such as a rocket or spacecraft.

 

Falcon 9:

Sleek, thin and white

Exhaling flame, it rises up

And pierces the sky

 

Falcon 1:

The first tech demo

A few hundred kilograms

Into Earth orbit

 

Dragon:

Launched on a rocket

The smallest of supply ships

For the ISS

 

Elon Musk:

South African-born

The head of two companies

He’s the CEO



The SLS is Unnecessary
April 12, 2013, 09:07
Filed under: Space stuff | Tags: ,

So, you may be asking yourself, why is this post called the SLS is unnecessary? Well, the SLS (Space Launch System) is a huge rocket currently in development by NASA. What is it for? Well, those of you who have been following spaceflight for more than three years may remember the Constellation program, which was supposed to succeed the Space Shuttle, but never got past its first test flight. When Constellation was canceled, the replacement for its LEO functions were given over to commercial enterprises such as SpaceX, while anything past that is scheduled to be handed over to the SLS. Something to note here is that SpaceX in particular has launched two different rocket designs on more than five successful flights while NASA was banging its head against Constellation and the SLS. Why is the SLS unnecessary? SpaceX for one is already developing another rocket as a near-heavy lift vehicle, and if someone would pay them, they could build something equivalent to the SLS, if such a large rocket is even needed. NASA is wasting time and money working on a giant needless rocket; however, if it ever does make it into space, I will be behind it all the way to splashdown, assuming the mission even includes one.

P. S. Today is the fifty-second anniversary of the first human spaceflight, Vostok 1 carrying Yuri Gagarin. Happy Yuri’s night everyone!



I am very sad.
August 26, 2012, 15:38
Filed under: Space stuff

First, an acrostic:

 

Notable

Eagle Scout

Iconic

Legendary

American

Lunar Pioneer

Decorated Hero

Engineer

NASA Crewmember

Astronaut

Reluctant Hero

Moonwalker

Scottish Ancestry

Test Pilot

Remembered

Octogenarian

Naval Pilot

Gemini commander

 

“That’s one small step for (a) man, one giant leap for mankind.” – Neil Armstrong

 

Neil Alden Armstrong, the first man to walk on the Moon and one of my heroes, died Saturday, August twenty-fifth at the age of eighty-two. He commanded two space missions, Gemini 8, which was cut short after the space capsule malfunctioned and spun wildly, and Apollo 11, when humans first landed upon another planetary body. Armstrong was joined on this mission by Edwin “Buzz” Aldrin and Michael Collins. My favorite bit of Armstrong trivia is an incident in 1979, which was this: he was working on his farm near Lebanon, Ohio, and his wedding ring caught in a latch on his grain truck as he was jumping off. Part of his finger was torn off, and he picked it up, packed it in ice, and drove to the hospital, where it was surgically reattached. He served as vice-chairman on the Rogers Commission which investigated the Space Shuttle Challenger accident in 1985. When I heard he had died of complications from coronary bypass surgery, I was stunned and decided to write this post with a poem in his honor.