The most important issue in space development is reducing the cost to orbit.
While there are
other possible ways to reduce the cost to orbit,
we feel that Single Stage To Tether is the most promising approach
(see flash demo).
Using a suborbital rocket of around 40,000 Kg gross mass,
you could take a payload of about 4,000 Kg
to the end of an orbiting spinning tether.
Because of the tether, the rocket only has to provide
a bit over half the delta-V of going to orbit.
This makes it
much easier to make the rocket
a reusable launch vehicle (RLV).
If the rocket is an RLV then the
cost to orbit could be as low as $6/lb.
This is more than 100 times cheaper than the
best current launch prices
of around $1,000/lb to LEO and $6,000 to GEO. This kind of savings can
be had with a modest tether tip velocity of 2.5 km/sec due to a
number of factors.
After the tether is fully loaded with solar cells and thrusters,
it could handle a 4,000 Kg payload every 90 minutes.
This would require a few RLVs.
huge potential market is tourism but
there are some
other markets for such a system
problems to be worked on.
Tethers have had a
bad reputation and there are some
reasons why tethers have not yet been used.
Still, this method of reducing cost to orbit seems very practical and with far
lower development cost and risk
than any other method of which I am aware.
I have a
few thoughts on who might finance this.
The key to getting the tether system up for a reasonabl cost is
bootstrapping from an initial small tether.
At first you could not fly your reusable rocket with a
full load, because the tether can not handle that much,
but it would still be the cheapest way into space.
We are working on an initial design we call
CateCATS1. From this we will
try to estimate time for rollout and costs.
An initial tether project could be using a
lunar tether to pickup regolith and return to Earth for fun and profit.
We also have a list of Future space projects that might become reasonable
once launch costs are reduced.
Used throughout these web pages are some
SpaceTethers.com Simulator and Rocket Equation Applet
We are working on a space tether simulator that
anyone can use for free. This
simulator can also be used as a "projectile simulator", "rocket simulator",
"drag simulator", "reentry simulator", "meteor simulator",
"solar sail simulator", or general "space simulator"
for looking at atmospheric
drag and heating on projectiles or rockets.
You may need to install the newest versions of
the Java JRE for the applets to run right. You can also
get a new Netscape or a
new Internet Explorer. To try the simulator,
click on "Run the Space Tether Simulator" below,
then click on "Design point"
or "Rocket 20km", and then click on "Start Simulation".
Dreams into Reality - Evolving and Spreading Ideas
Good ideas are recognized as such and spread. I got most of the ideas for this web site from discussions with
my father, Henry Pratt Cate Jr., starting in late November 2002. He has recognized
their merit from published papers, space conferences and the Internet. Some publications
similar to the ideas on this site are
paper in 1995, and
one in 1982.
Henry Spencer has discussed the idea.
Some of the key people in spreading tether ideas over the last 10 years have been
Robert Hoyt and
Many tether ideas were published by
Robert Forward, and Arthur C. Clarke more than 20 years ago.
Jerome Pearson is
still active in tethers
It seems Hans Moravec heard of tethers from
John McCarthy who thought about tethers in the 1950s.
Some people call a spreading idea a meme (see
I think that spreading the ideas on how we could get to the moon was an important
part of actually getting to the moon.
Robert Goddard said,
"It is difficult to say what is impossible, for the dream of yesterday is the hope of today and the reality of tomorrow."
In a 1920 report Goddard
outlined the possibility of sending a rocket to the Moon.
Robert Heinlein worked on
the movie "Destination Moon" (1950)
and Wernher Von Braun (who studied Goddard) worked on
Colliers magazine articles (1952)
TV show "Man and the Moon" (1955) with Disney.
Likewise, spreading ideas for ways to achieve low cost to orbit
should help us actually get low cost to orbit.
space enthusiasts are too pessimistic right now.
I am trying to publicize the ideas I like best with this web site and
posts to newsgroups.
If you like these ideas, and want to see this dream turned into reality,
do what you can to spread the word,
link to us, tell others, email someone, etc.
For more information on Space Tethers
Some other sites I like
wikipedia space colonization
- SPENVIS - SHIELDOSE-2radiation absorbtion model
- my space book collection and recommendations
- MiningAsteroids.com - another site I have started
- CNN Space,
SpaceDaily.com - space news
SolarViews.com - space news and reference sites
- yarchive.net - archive of good netnews posts on space groups
- Space Software Swiss Propulsion Lab,
Amateur Rocketry Links Library,
- guys making real hardware for low-cost rockets
- The Space Show Internet radio shows about space
- Space Frontier,
National Space Society,
British Interplanetary Society,
Space Studies Institute,
NASA simulators in particular the
NASA Engine Simulator
NASA's Discovery missions
Orbit-on-Web orbit utilities
- High Altitude Glider - weather balloon and robot glider with GPS to fly home
- AmSat / HamSat - very small HAM satellites (as small as 0.22 Kg)
- Why Are Launch Costs So High?
Project Orion by George Dyson or nuclearspace.com
- life on Earth probably came from space
EARTH-TO-ORBIT TRANSPORTATION BIBLIOGRAPHY by Andrew Nowicki - lots of wild ideas
- How Stuff Works - Space Library
- CBS News space stats - less than 500 people have been to space
- panoramic Apollo pictures of the Moon
- umich.edu radinfo
For questions/feedback on the ideas/info/simulator/code/web-pages here please send email
me at vincefour at offshore.ai but replace four with 4 and " at " with "@".
I would like to make the
information here as accurate as possible and any help is appreciated. I believe that
by accurately simulating much of this project we can know what is really possible.
Copyright (c) 2002 - 2006, by Vincent Cate. All rights reserved.