Transfer orbit stage

Transfer orbit stage

The Transfer Orbit Stage (TOS) was an upper stage rocket developed by Martin Marietta on a subcontract to Orbital Sciences Corporation during the late 1980s and early 1990s. Orbital Sciences was the prime contractor for NASA for TOS. TOS was developed to be a lower-cost alternative to the very flexible but significantly more expensive Inertial Upper Stage (IUS) or Titan Centaur.

TOS was composed of an Orbus 21 solid rocket motor with hydrazine-fueled thrusters for orbital maneuvering. TOS navigated via a Honeywell produced ring-laser gyro (RLG).

The TOS control system employed a digital optimal, time-scheduled control algorithm for stability during solid motor burn and a phase-plane controller for management of its reaction-control system (RCS). This provided exceptional stability during maneuvering.

Separation from the TOS was provided by Super-Zip connectors with the option for a spin-stabilized separation.

TOS participated in two missions during the program lifetime, both of which suffered mishaps:

* Delivery of the Advanced Communications Technology Satellite (ACTS) to orbit via the Space Shuttle, and
* Delivery of the Mars Observer (MO) space probe to Mars with launch provided by Commercial Titan.

During the ACTS mission, TOS suffered a misfire of its Super-Zip separation system such that both the primary and backup Super-Zip connectors were simultaneously fired. This threw shards into the lining of the Space Shuttle bay, causing safety concerns. The Space Shuttle successfully returned to Earth afterwards. For the Mars Observer mission, the boost to Mars and following Collision/Contamination Maneuver (CCAM) were as expected and the boost to Mars were either to or superior to the plans. However, the Mars Observer failed to contact the mission controllers after the transmitter was turned off for Mars Orbital Insertion (MOI).

After these two mishaps, no further TOS missions were booked and the program was eventually cancelled.

Note:

For the Mars Observer mission the command to turn off the transmitter was sent after the TOS stage separated from the spacecraft, where TOS performed as designed or better.

According to the http://www.astronautix.com/craft/acts.htm the ACTS mission went off flawlessly.

The TOS program was not cancelled, it was only scoped for two missions.


Wikimedia Foundation. 2010.

Игры ⚽ Поможем сделать НИР

Look at other dictionaries:

  • Geostationary transfer orbit — A Geosynchronous Transfer Orbit or Geostationary Transfer Orbit (GTO) is a Hohmann transfer orbit around the Earth between a low Earth orbit (LEO) and a geosynchronous orbit (GEO). It is an ellipse where the perigee is a point on a LEO and the… …   Wikipedia

  • Parking orbit — A parking orbit is a temporary orbit used during the launch of a satellite or other space probe. A launch vehicle boosts into the parking orbit, then coasts for a while, then fires again to enter the final desired trajectory. The alternative to a …   Wikipedia

  • Inertial Upper Stage — The Inertial Upper Stage or IUS is a two stage solid fueled booster rocket developed by NASA and the U.S. Air Force for the launching of large payloads from either a Titan III (later Titan IV) rocket or from the payload bay of the Space… …   Wikipedia

  • inertial upper stage — a U.S. two stage, solid propellant rocket used to boost a relatively heavy spacecraft from a low earth orbit into a planetary trajectory or an elliptical transfer orbit. Abbr.: IUS Cf. payload assist module. * * * …   Universalium

  • inertial upper stage — a U.S. two stage, solid propellant rocket used to boost a relatively heavy spacecraft from a low earth orbit into a planetary trajectory or an elliptical transfer orbit. Abbr.: IUS Cf. payload assist module …   Useful english dictionary

  • Automated Transfer Vehicle — The Automated Transfer Vehicle or ATV is an expendable, unmanned resupply spacecraft developed by the European Space Agency (ESA). [cite web |title=Automated Transfer Vehicle, ESA document EUC ESA FSH 003 Rev 1.2 (specification)… …   Wikipedia

  • Centaur (rocket stage) — Centaur is a rocket stage designed for use as the upper stage of space launch vehicles. Centaur boosts its satellite payload to its final orbit or, in the case of an interplanetary space probe, to escape velocity. Centaur was the world s first… …   Wikipedia

  • Space Shuttle — STS redirects here. For other uses, see STS (disambiguation). This article is about the NASA Space Transportation System vehicle. For the associated NASA STS program, see Space Shuttle program. For other shuttles and aerospace vehicles, see… …   Wikipedia

  • Mars Observer — Artist rendering of Mars Observer in orbit around Mars. Operator NASA / JPL …   Wikipedia

  • Payload Assist Module — PAM D with the Phoenix spacecraft. The Star 48 B engine is shown being spun, fired, yo yo de spun and jettisoned. SBS 3 satellite with PAM D stage inside the space shuttle …   Wikipedia

Share the article and excerpts

Direct link
… Do a right-click on the link above
and select “Copy Link”