Conestoga (rocket)

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The first, and only, Conestoga 1620, prior to its launch from Wallops Island. The engine bells on the various clustered boosters indicate their firing order, those with the largest bells are tuned for higher altitudes.

The Conestoga was a rocket design funded by Space Services Inc. of America (SSIA) of Houston, Texas. Conestoga consisting originally of surplus Minuteman missile stages with additional strap-on boosters, as required, for larger payloads. It was the world's first privately funded commercial rocket, but was used only three times (one as a modified design) before the program was shut down due to a lack of business.

It was purchased by L-3 Communications in 2001 for $110 million.


SSIA had originally intended to use a design by Gary Hudson, Percheron, which was intended to dramatically lower the price of space launches. Key to the design was a simple pressure-fed kerosene-oxidizer engine that was intended to reduce the costs associated with "throwing away" the booster. Various loads could be accommodated by clustering the basic modules together. SSIA conducted an engine test firing of the Percheron from Matagorda Island on August 5, 1981, but the rocket exploded on the pad due to a malfunction.[1] SSIA then parted ways with Hudson.[2]

Conestoga I[edit]

SSIA founder David Hannah then hired Deke Slayton, one of the original Mercury Seven astronauts. Slayton had just left NASA after running (among earlier roles) the Space Shuttle Landing and Approach validation testing. They came up with an entirely new design based on clustering engines from the second stage of the Minuteman missile. The first launch of the new Conestoga I design took place on 9 Sep 1982, consisting of the core missile stage and a 500 kg dummy payload which included 40 gallons of water. The payload was successfully ejected at 313 km, and the Conestoga I became the first privately funded rocket to reach space.[3]

SSIA launched a second rocket in 1989, turning to commercial support for microgravity experiments, using the Black Brant sounding rocket which they referred to as "Starfire".

Conestoga 1620[edit]

Destruction of the Conestoga-1620. Not all motors were rendered nonpropulsive in response to the flight termination system command and can be seen corkscrewing out of control.

SSIA was purchased by EER Systems in December 1990. The design was modified again, this time using the Castor engines originally used on the Scout, a workhorse of the 1960s. The new design was known as the Conestoga 1620, or by other numbers depending on the number and arrangement of the boosters.

In May 1990 the Center for Space Transportation and Applied Research (CSTAR) pitched NASA on their Commercial Experiment Transporter (COMET) payload concept, a low-cost standardized bus with both sub-orbital and orbital components. Rides on the COMET promised to be longer than existing sounding rockets, and the orbital portion would be free-flight and thus not disturbed by crew movement as it was on the Space Shuttle. Westinghouse agreed to provide the bus and "service module", Space Industries Inc. built the re-entry module, and EER was contracted to provide several Conestoga launchers.

The entire COMET program quickly ran into delays and budget overruns, and it was not until the end of the program that a COMET (now known as METEOR) and Conestoga 1620 were finally ready for launch. The satellite payload included a number of experiments, including materials (evaluate exposure to the caustic space environment), biological (assessment of seed reaction in micro-gravity; growth fluids were to be injected to the seed containers after launch), as well as GPS/radar correlation tracking. The satellite included a recoverable section that was to separate on command after several weeks on orbit, fire a small internal retro-motor, and descend for a recovery off the Virginia coast. The launch took place from a special clamshell gantry, which included power and environmental controls, at the south end of Wallops Flight Facility on 23 October 1995; the rocket launched normally, but broke up in-flight 46 seconds later. EER concluded that an unknown source of low frequency noise caused the guidance system to order course corrections when none were needed, eventually causing the steering mechanism to run out of hydraulic fluid. An earlier NASA review had already decided to refuse further funding due to the original delays, and EER subsequently got out of the rocket business.

Conestoga Versions[edit]

Due to the modular design of the Conestoga, a large number of configurations were possible. Therefore the version number encoded the configuration:

  • the first digit encoded the type of rocket motor used in the cluster
  • the second was the number of motors clustered around the core
  • the third was the type of the first upper stage
  • the fourth was the type of the second upper stage
Version Stages Stage 1 Stage 2 Stage 3 Stage 4 Stage 5 Payload (kg)
Conestoga 1229 4 2 Castor-4B 1 Castor-4B Star-48V HMACS - 363 kg
Conestoga 1379 4 3 Castor-4B 1 Castor-4B Star-63V HMACS - 770 kg
Conestoga 1620 4 4 Castor-4A/B 2 Castor-4B 1 Castor-4B Star-48V - 1179 kg
Conestoga 1669 5 4 Castor-4A/B 2 Castor-4B 1 Castor-4B Star-63D HMACS 1361 kg
Conestoga 1679 5 4 Castor-4A/B 2 Castor-4B 1 Castor-4B Star-63V HMACS 1497 kg
Conestoga 3632 5 4 Castor-4A/B-XL 2 Castor-4B-XL 1 Castor-4B-XL Orion-50 Star-48V 2141 kg

Various Conestoga configurations, with the COMET launcher highlighted.

See also[edit]


  1. ^ Woods, Michael (Sep 23, 1981). "Rocket Failure Brings Favorable Fame: Private Effort Ended In Launch Explosion". Toledo Blade (Toldeo, OH). p. 1. 
  2. ^ Richman, Tom (Jul 1, 1982). "The Wrong Stuff". Inc. 
  3. ^ Abell, John C. (September 9, 2009). "Sept. 9, 1982: 3-2-1 … Liftoff! The First Private Rocket Launch". Wired.