The two biggest barriers to getting the funding for building the DH-1 are:
- The acceptance of simple engineering in the rocket area
- Getting over he believability hump
Simple Engineering
The
simple engineering approach is to cut back all the unnecessarily
complex approaches to aerospace engineering and focus on building things
that will work reliably. Accept the compromises where they need to be
made instead getting bogged down trying to develope new technology to
solve all the aspects of a problem. Focusing on the achievability of the
whole mission, not any single piece of technology. An example of this
is the design of the U2 spyplane with its unstable flight
characteristics and unusual landing gear, but over the last 50 years it
has proven to be one of the most effective ways of doing that high
altitude spy missions. Being able to accept the compromises in design to
achieve the mission is a big mental hurdle.
Instead
of having the design drivers being low weight and maximum efficiency,
have the design drivers as being the simplest approach which will enable
to job to get done. This means that instead of trying to build the
space shuttle, with its incredible complexity, we instead try to build a
DC-3. Overengineering the first vehicle is not something to be avoided
but encouraged! We simply dont know what the working environment will be
for a reusable launch vehicle which operates on a daily or weekly
basis. We therefore need to focus on getting a vehicle which will
survive for a sufficiently long number of launches to prove the concept.
The very first DH-1 will likely have a very small or zero payload. But
it will truly be reusable, and the experience gained will be invaluable.
The Believability Hump
The
second barrier is the believabily hump. Most people will not be able to
understand how simple and robust the DH-1 concept is until they see it
in operation. Therefore we need to have a way of starting small while
still keeping all the important aspects of the design. One idea which I
have recently found is to first create a smaller reusable sounding
rocket. This would be a single stage vehicle that combines both the
first and second stage ideas. There is a very good article by Yoshifumi
Inatani over at
www.spacefuture.com
detailing the design of a reusable VTOVL design and the emphasis on
reliable operability. Although it doesnt have the capability to reach
orbital velocity it can still reach an altitude of over 300 km.
This
rocket also has a payload of 100kg, which is a lot more than most
sounding rockets, with a much larger payload bay volume as well! Because
it is reusable with quick turnaround times it would greatly reduce the
whole cycle of developing an experiment through to launching. I feel
that if this cycle can be reduced to months instead of years then it
will allow a lot more interesting work to be done. Instead of having a
sounding rocket launch be a once in an education experience, it could be
a once a semester type of experience. Most importantly it would show
that the model of having much simpler yet more robust launch vehicles
being turned around rapidly is a significant advantage.
I
would envisage a small single stage reusable sounding rocket such as
this being built for a couple of million dollars. The aim would be to
assemble a small team of engineers to design and build this, operating
on the X plane development model. This would enable the software and
analysis to be done in smaller easier steps and verify the concept
before too much money needs to be spent. This experience would then
enable better engineering and design choices to be made once the full
DH-1 developement occurs.
The Side Note
There
is some great video footage from onboard the
Armadillo Aerospace Stiga
sounding rocket. An interesting look
at what the world is like from 40km up!
