1. Project Concept
we are trying to achieve is best described graphically, so make note
of this diagram. It will be the guiding idea of this whole endevour.
2. A Sample Orbiter Addon Package
the sample Addon pack provided, you take on the role of an experienced
pilot astronaut, that is given the task to reach the MSS (Medical
Space Station) in time to prevent an astronaut in EVA to lose his
oxygen supply and die. The astronaut is unconscious, floating near
the MSS, the skeleton crew of which can do nothing but watch and wait
for your arrival.
will be flying a DeltaGliderIII ready for launch sitting on a pad
at Cape Canaveral and facing the proper launch direction of 42°,
which will be later corrected to 47° by the flight computer so
leave it as it is. For this emergency you are allowed to take off
directly, without using the runway and without having to hover from
the pad first before engaging main engines. You may, this once, just
push the pedal to the metal when the time is right.
must reach the helpless astronaut within 50 minutes, before his oxygen
supply runs out. Remember what you learned, pay attention to the inflight
instructions and keep your mind focused on the task. Good luck!
(Alpha Version) [Accessed
of the voice script
(Excel table) [Accessed
cockpit with a view!
Can you get to the astronaut in less than
3. Steps needed to create a Direct Ascent and Docking Project
Define the Ascent Program parameters for the DGIII
flight computer. Make sure the program gets you to the right altitude
for you to intercept the orbiting target and consumes a miminum of
fuel required to achieve the circular orbit at that altitude. There
are many possible trajectories and any that brings you into an orbit
of acceptable parameters at a decent fuel costs will do. Although
calculation of the required pitch attitudes by altitude is no doubt
possible, I suspect it to be so complex, as to become unpractical
for our rather unexact needs.
the Launch Azimuth best suited for your needs. Roughly two
options for a launch azimuth needed by the flight computer are possible.
If you are skilled in math you can calculate it otherwise it is by
trial and error. Not something one is liable to do in real life in
approach is to achieve orbit and to perform MECO at
the closest point to the targeted object.
This method is the fastest, however costs insane amounts of fuel
to cancel out the velocity acquired during the Ascent stage. Most
of this counter velocity will be vectored to bring the relative
inclination (RInc) of the two orbits to 0°. The proper timing
is also hard to calculate and/or judge. Also the target starts to
move away rapidly after closest distance has been achieved and there
is little margin for error.
second approach is to set your launch azimuth to minimize
the distance the two craft will have at plane intersection point
(in this case the Ascending Node -AN). At that point you are able
to both perform the retro burn to decrease relative velocity with
regard to the target object AND at the same time cancel our the
relative inclination you have failed or were unable to cancel out
during the ascent. It is quite common that the two burns are similar
if not identical in direction and magnitude, which makes this approach
a lot more appealing and fuel efficient. The object passes by the
vessel in a much slower manner and also moves away, once closest
distance has been achieved in much slower and more controllable
manner. I recommend this approach as it is more predictable
Define the launch window that enables you to pass
the target at the closest possible range, so you have less to do after
your finish your retro burn and find yourself in a static position
with regard to the target. Again sequential testing is needed if you
lack the proper mathematical expertise.
hope you have as much fun with the Direct Approach as I have had making
and testing it.