|
Foreword - Buzz Aldrin
Tom and I do not see eye to eye on everything. For example, he proposes putting propellant depots in low Earth orbit and using
commercial launch services to supply them. I think that the infrastructure would be much more useful at the gravity-balance
point between the Earth and the moon, but these are trivialities in the scope of human history. We both strongly agree that
humankind must look outward to the planets and eventually the stars, moving beyond the cradle of Earth. Tom is a visionary,
and has a gift for turning his visions into engaging text while keeping the critical information intact.
Chapter One: Where We Are
There are many within the space advocacy community that believe that larger space prizes, offered by groups such as the US
Government, would open a new chapter in affordable space activity without repeating mistakes of the past. In recent space
development projects, government agencies embark on grand projects, promising either to revolutionize space travel, or demonstrate
that such a revolution is possible. As problems mount for the program or priorities shift within the government, those projects
are cancelled, but the money ($5B according to a USA Today article) to develop the system has still been spent. The years
1986-2003 may hold those failures as America's space agency's primary legacy.
Chapter Two: How We Got Here
A second round of soul-searching took place in 1961, when the Soviet Union launched Yuri Gagarin to complete one orbit of
Earth on April 12th. US efforts were again called into question, since their first crewed flight wasn't scheduled until May,
and it only involved launching a craft a few score miles away from the launch site. The newly inaugurated Kennedy Administration
scrambled to find a way to turn this political tragedy into something positive. They fell upon an interesting idea, in that
space spectaculars were a way to demonstrate superiority without direct warfare.
Chapter Three: The Columbia Tragedy
When interviewed, NASA managers said that the schedule pressure did not force unsafe or unsound decisions related to operations
or processing. Workers on the floor said that schedule pressures did lead to unsafe or unsound decisions, but that they felt
powerless to claim that as the case, because there was no failure to point to as a symptom.
February 19, 2004, passed without the ISS achieving US Core Complete status.
Chapter Four: Space and Popular Culture
In the future, as space flights become longer because of their destinations, the astronauts will be spending a portion of
their time simply traveling. The timelines here are pretty impressive, too. While some asteroid missions have been advertised
as 30-day one-way trips, the journey out to Mars will take 200 days. During the trip out to Mars there will be no science
for a crew to do, and maintenance should be minimized because they're in a brand new craft that has to support them for a
total of two and a half years. Here, the best news coverage comparison that can be drawn is that of broadcasting news from
the passenger cabin of an airliner crossing the Atlantic. Now there's some exciting television viewing!
Chapter Five: Space Activism
In today's society of tailor-made activism, someone interested in space travel can find a group of like-minded people fairly
easily. What's more, a person can choose their own political agenda related to space, whether it be increased uncrewed exploration,
private enterprise taking over space (leaving government to their typical roles of policing and setting policy), or advocating
a specific destination for humans on their expansion outward. In my opinion, this kind of division can be good because it
draws people in with different ideas, but I'm pretty sure that a lack of common goals produces more confusion among the very
people that these societies are trying to reach-the public and their elected officials. Imagine being a civic group member
who has only a passing interest in space from day to day. You go to your weekly meeting and get a presentation from The Artemis
Society about how people need to return to the moon. Two weeks later, you go to your meeting and get a talk from The Mars
Society stating that the moon is a diversion on the route to Mars, and has very little value without the development of fusion.
Granted, these discussions are the point of much debate in space circles, but what impression does it leave with someone who
doesn't check Space News every day? Let's take a look.
Chapter Six: A Robust, Expanding Space Presence
One answer to this problem is to have a standby space rescue service ready to launch on a couple days' notice to rescue a
crew in orbit. Please note that when we achieve the goal described in the first section of this chapter, multiple methods
to orbit, the requirement of standby rescue should be met. (This assumes that all the available spacecraft are designed with
some compatibility in mind, and setting those standards is an excellent role for a government agency, by the way.) In modern-day
terms, this translates to having a space shuttle sitting on the ground that can be made ready to launch in a fewer number
of days than the scheduled mission duration. Granted, if the scheduled mission were headed to the International Space Station,
ground crews would have a little more time to prepare. The question is: is this feasible?
Chapter Seven: Expansion Outward: Where do we go From Low Earth Orbit?
The goals for crewed high Earth orbit missions are, for the near term, largely equipment checkout and initial crew radiation
exposure experimentation. High Earth orbit locations have an advantage over low Earth orbit stations in that they create an
environment very similar to what a spacecraft will experience in a long-term mission to another planet or an asteroid (see
the appropriate section of this chapter). Some of these similarities include the radiation environment (see challenges, below),
a nearconstant source of solar power, and long-term communications capability with Earth. Unlike those long voyages, however,
a crew that's in a high Earth orbit has the option of a rather quick return to the mother planet. Using one option, in the
form of a highly elliptical orbit, the spacecraft will return to Earth utomatically. If this type of auto-return isn't desired,
a craft can be sent to one of the Lagrange points for a long-term stay, with a small rocket firing bringing the craft back
in a matter of days or weeks.
Chapter Eight: Future Tense: How it Could Happen
While I maintain that I will support any effort to take us deeper into space for the long term, I don't believe that a purely
government-funded program is the answer. I believe that government has a role to play in such expansion, either in a hybrid
arrangement that I'll talk about in a bit, or a government agency like ComSat, that's designed to turn into a commercial venture
over time. Pouring more money into an existing bureaucracy is not the best answer for taking humans into space to stay.
Chapter Nine: Yes, but What Should Happen Now?
So, to avoid the "crash" approach taken by Apollo, this mandate for Mars gives NASA and the other space agencies
of the world the opportunity to build the hardware for Mars exploration, while at the same time, tasking them to work on low-cost
access to space. The low-cost portion of the mission is possible because when a Mars mission (built to fly using chemical
propellants) is in low Earth orbit, it is made up of approximately 70 percent propellants. Propellants can be carried to
orbit relatively easily, either using the orbital supply depot described earlier or by carrying the fuel (hydrogen) and oxidizer
(oxygen) separately. By contracting to have these propellants delivered on orbit, space agencies can then focus on building
the necessary hardware for exploration, not propellant storage (as the tanks holding hydrogen and oxygen specialize in, even
though they supply rocket engines and make the mission possible). With a burgeoning commercial launch industry coming together
for delivering propellants to orbit, combined with a new round of development for spacecraft to go beyond LEO, a true renaissance
in space travel may be upon us.
Chapter Ten: The New Space Policy of the United States
Since [the space exploration initiative announcement in 1989], I've seen the first "We're going to Mars!" charge
not even get out of the gate. I've worked in the space industry for close to 15 years, seeing how things work on a day-to-day
level. Once, I even experienced the exhilaration of granting the final "Go" for a satellite launch, then felt the
ground shake beneath me as a rocket roared to life 1200 feet away, starting its payload's successful journey into orbit. I've
watched as the space station has slowly, haltingly, come together through budget and technical difficulties. My footsteps
have echoed the halls of Congress, as I've spoken to staff members for my representatives and others, trying to convey my
beliefs in the space program to them. I've spoken to the public, at times feeling their excitement while at others catching
very barbed questions from sources I didn't expect. I've also heard from another side of the space community, those that think
it's time for the government to turn over the reins to commercial efforts.
Chapter Eleven: The Technical Stuff
In space missions, you'll often hear about a spacecraft making a close approach to a planet to "slingshot" its way
further out into space. This is a trick that's been used since the '70s and some missions have made use of several slingshots
to make their mission possible. How does this work? As usual, we'll start with an example.
Take a rubber ball and throw it straight down on the ground. If you have any skill at all, the ball will bounce right
back up to near your hand, and you'll be able to catch it again. You can do the same thing against a wall, although this throw
may take a little more skill. Now, while it's true that there are some losses when the ball bounces, it leaves the wall with
almost exactly the same energy that it arrived with.
Let's shift the vision, so that now you're bouncing the ball off the front of a box car in a railroad yard. If the car
is standing still, the ball bounces away from the car the same as it would bounce away from a wall. If the car is coming towards
you, and you throw the ball against it, when the ball returns to you (just before you jump out of the way of this moving car,
of course) it is moving faster than when you threw it.
|
