Wednesday, December 14, 2005

SS2S, or "how to get to space on 885 lbs of candy"

SS2S (Sugar Shot to Space) is an amateur project whose goal is to launch a rocket to over 62 miles (100 km) using sugar propellant (a.k.a. rocket candy). Sugar propellant is a popular amateur propellant that consists mainly of an oxidizer and, obviously, sugar. The latter can be common sucrose, or other sugars such as sorbitol or dextrose. The Isp of these propellants is not as high as that of Ammonium Perchlorate Composite Propellant (APCP), which is used in the Space Shuttle SRBs and commercial hobby motors - and herein lies the main challenge. Other amateurs have flown this high, but not on sugar! One of the key players in this project is Richard Nakka, who maintains the most comprehensive web site on these propellants.

The SS2S team completed an initial feasibility study and is currently in the design phase. They are also actively building a 1/4-scale motor. Due to technical and regulatory concerns, they could not go with a multi-stage rocket, so they will use a 2-phase segmented motor. In this type motor, the lower part of the propellant burns (phase 1), there is a coast period while a delay grain burns, and then the top portion of the motor ignites (phase 2).

Here is a summary of the preliminary vehicle specs:
  • Number of stages: 1 (dual-phase operation)
  • Vehicle size: 10"” (25.5 cm) diameter by 26'’ (7.9 m) overall length
  • Liftoff mass 1100 lbs (495 kg).
  • Allotted payload mass 15 lbs (6.8 kg).
  • Full vehicle recovery
  • Propellant type, cast Potassium Nitrate/Sorbitol (KNSB)
  • Propellant mass 885 lbs (402 kg), consisting of 6 BATES segments per phase (12 total)
  • Burn time 8.5 seconds each phase (17 sec. total)
  • Motor average thrust, 6665 lbf (29.6 kN)
  • Coast time between firings, 16 seconds
If you want to track this project, you can sign up for their email list (see the About Us page).


  1. How does the coast phase improve performance? Does it reduce drag losses?

  2. You are correct. Aerodynamic drag is proportional to air density and the square of the velocity. Thus, is is beneficial to let the rocket coast prior to 'second stage' ignition.

  3. This is the latest on the Sugar Shot to Space program:

    We are now preparing our second MiniSShot flight and starting the DoubleSShot project.

  4. Thanks for the update. I've been tracking the project via the mail list but had forgotten how long this has been going on!

  5. This weekend I will be having a friendly competition at the FAR site with a friend that does hybrids to see who's motor is "best"...whatever that means. National Geographic will be there filming the event.

  6. That's cool, please let me know how it goes. I assume the motor classes will be comparable? At least theoretically.