International Extreme Ultraviolet Hitchhiker

past Mission




Oct. 29, 1998


Solar System, Universe


Seven experiments sent to space on a shuttle

The seven IEH-3 experiments were attached to a carrier system in the bay of the Space Shuttle (STS-95). They studied the Jupiter system, hot stars, planetary and reflection nebulae, and variations during a solar cycle.


Seven experiments made up the IEH-3 payload on the STS-95 Space Shuttle mission. The seven hitchhiker experiments were attached to a carrier system in the bay of the Shuttle orbiter for the flight in space. Some experiments were controlled from the Payload Operations Control Center at the Goddard Space Flight Center in Greenbelt, Md., while others ran automatically with pre-programmed commands which were loaded into their operating computers before launch.

Ultraviolet Spectrograph Telescope for Astronomical Research

UVSTAR was an extreme ultraviolet spectral imager designed as a facility instrument devoted to solar system and stellar astronomy research. The instrument was designed to obtain and spectrally resolve images of extended plasma sources including the plasma located around Jupiter's moon, Io, and hot stars (stars that put out more energy than regular stars). Io, which is volcanic, spews out volcanic gasses and materials that get trapped in the magnetic field of Jupiter forming a Torus ( a donut shape with Jupiter in the middle). The ultraviolet emissions from the Torus will reveal the material on Io, the energy output of Jupiter and so on. The telescope was designed to also measure the emissions from the Earth's atmosphere, acquire data from celestial targets and perform atmospheric science.

The Extreme Ultraviolet Imager (EUVI), another instrument aboard UVSTAR, took measurements of the Earth's atmosphere in the extreme ultraviolet wavelengths while in any attitude. The EUVI contained two imagers that map the intensity of helium and oxygen ions in the atmosphere by scanning along the Earth's shadow line. This instrument was designed to provide precise measurements of the Earth's ionosphere and plasmosphere.

Spectrograph/Telescope for Astronomical Research

STARLITE was a telescope and imaging spectrograph used to study astronomical targets in the ultraviolet. Targets of scientific investigation include diffuse sky background emission, scattered dust and recombination emission lines from the hot and interstellar medium, supernova remnants, planetary and reflecting nebulae, star forming regions in external galaxies and the Torus formed around Jupiter from the volcanic emissions of the moon Io.

Solar Extreme Ultraviolet Hitchhiker

The SEH experiment was designed to obtain absolute Extreme Ultraviolet (EUV)/Far Ultraviolet (FUV) fluxes (energy output) used to interpret EUV/FUV emissions from solar system objects, interplanetary medium, plasmosphere and magnetosphere (layers of the Earth's upper atmosphere). SEH was designed to measure changes in the Earth's atmosphere due to solar extreme ultraviolet and daytime temperatures.

SEH was designed to achieve solar science objectives of measuring the absolute solar EUV irradiance, the flux of radiant energy per unit area for planetary atmosphere studies. Another goal was to analyze and interpret the solar EUV data for the purpose of improving global solar atmospheric computer modeling, and thus improve our understanding of solar variability.

Solar Constant Experiment

The SOLCON instrument was designed to accurately measure the solar constant (total solar radioactive power absorbed by one square meter at the mean distance between the Earth and Sun) and identify variation during a solar cycle. This measurement was accomplished by determining the power difference required to bring two hollow points into thermal balance when one is open to the Sun and the other closed. The data will ensure continuity of the solar constant level obtained by instruments mounted on other free-flying spacecrafts. Solar energy is the only external energy source for the Earth, thus a primary driver for climate change. This study is important to researchers studying the effects of global warming.

Petite Amateur Naval Satellite

PANSAT was a small non-recoverable satellite developed by the Naval Postgraduate School (NPS) in Monterey, Calif., which was launched via a Hitchhiker Ejection System located in the cargo bay of the Space Shuttle.

The objectives of the PANSAT satellite were to enhance the education of the military officers at NPS through the development and operation of a spread spectrum satellite. Spread spectrum satellites allow communication satellites to capture and transmit a signal that normally would be lost because the original signal was too weak or had too much interference.

Normal radio frequencies, use about three kilohertz to a megahertz of bandwidth, but spread spectrum is approximately a thousand times wider. This type of communication is difficult to intercept. The low probability of interception would be important for the military during downed pilot rescues. The downed pilot could obtain his location through a GPS system and uplink the data to the orbiting satellite with minimum risk. Civilians would be able to utilize this type of communication during emergency rescues, and as a basis of establishing communication to remote areas.

PANSAT was designed to be able to demonstrate the capabilities of low-cost spread spectrum which can be used to enhance military communication through a small satellite platform. The satellite was designed to provide, store, and forward digital communication using direct sequence, spread spectrum modulation. Store and forward digital communication allows the PANSAT ground station to send data to the satellite. The satellite will then process the data and retransmit it to the ground. Simply put, it is a mini-telecommunications satellite like the ones that handle telephone calls. It operated in the frequency range of the amateur radio community.

G-764 Get Away Special Experiment

CODAG was an experiment designed to stimulate the aggregation of dust particles which occurred at the early stages of our solar system. By understanding the dust growth process in the early solar system, it is possible to answer the questions of planet formation.

The experiment consisted of a vacuum chamber equipped with windows and sensors. The dust cloud was injected into the chamber and two high speed cameras, mounted at microscopes, recorded the dust motion in a small control area. Xenon lamps illuminated the experiment chamber and the microscope plane identified the three dimensional motion. The sensors measured the scattering characteristics of the dust cloud to compare it with astronomical measurements. As the dust portion was injected into the experiment chamber, it was observed for a period of 15 minutes to five hours. The chamber was purged for a new experiment while the recorded images were compressed for the mass memory. In total, ten single experiment runs were planned.

G-238 Get Away Special Experiment

The GAS payload G-238 was sponsored by the American Institute of Aeronautics and Astronautics - National Section and managed by students at DuVal High School in Lanham, Md. Aboard the payload, there was one biological experiment. This experiment looked at the effects of space on the life cycle of the American cockroach.

The roach experiment consisted of a habitat divided into three sections: one section each for young adults, nymphs and eggs. Small holes in the habitat container supplied air to the habitat. In each section, water was supplied in small vials with a wick through the top and food was provided in the form of dog biscuits. When in space, batteries supplied power to the heaters to keep the habitat at a comfortable temperature for the insects. An eight millimeter camcorder and lights connected to a timer recorded the activity inside the habitat at regular intervals.

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