Wednesday, July 22, 2009

Such a great idea...

Such a great idea, yet even Estes doesn't seem to
want to build one. WTF?
In the 1997 Estes catalog there was a kit that never
reached production. It was a model of a fly-back booster
called Star Booster. It's based on descriptions in Buzz
Aldrin's sci-fi book; Encounter with Tiber. copyright 1996
Great book by the way. I dug it up for this post and then
read it all again.

In the book, the Star Booster is built by Boeing to take
a slide-in Zenit motor/tank assembly, built under license,
in the USA. One or two of them would be attached to a
core vehicle as a strap-on like an SRB is. After using up
it's propellants, the Star Booster would seperate from the
core vehicle then glides back to an automated runway
landing near the launch site. After each flight, the Zenit
is removed for seperate servicing. When the airframe is
ready, the next available Zenit gets installed for a quick
BTW; Boeing really is building licensed Zenits for the
Sea Launch commercial launch program.

The Estes Star Booster model was going to be 18" long,
with a 9.5" wingspan, parachute recovery, C motors only.
By the looks, I expected it to have a cast styrofoam
fuselage over a cardboard core tube, just like the large
Shuttle Orbiter kit of the same time period.

I've been looking at the Estes Star Booster recently  with
ideas for reproducing it. I have hot-wire foam cutting
equipment, so it's not a big stretch for me to model it at
the original size or larger.  The difficult part is that not
only do I want it to glide, I want it to glide with an unfair
chunk of reload casing inside it. In short, a realistic mission
as afly-back strap-on,  boosting a level 2 size rocket.  For
the sake of balance it needs a long thin motor case.  Either
a 29/360 or 38/480+ sized case, probably EX  and burning
sugar. The big trade-off [ya can't design anything without
trade-offs] is, to maintain balance, the bigger the  model,
the longer the motor case needs to be, and  vice-versa.   
Of course, it'll glide like a brick!

For more info see;  Fly-Back Boosters, Reprised
right here at ZZakk's Lab on Monday, May 18, 2009
These 2  posts [of 3 before long] were supposed to coincide
more closely, but I'm easily distracted.


  1. Sounds awesome. Why an EX sugar propellant, though?

  2. 'Cause that's what I do.
    I like working with sugars, it's kind of an underdog thing for me, plus there's more science to be done with it still, compared to composites.
    For a Star Booster long 29mm commercial reloads are as likely, and lighter. But for 38mm, I have sugars developed for the job. Moonburners are especially good for strap-on motors, gentle ramp up, gentle taper off, less chance of disrupting the core vehicle flight path.