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A spin around the IBEX spacecraft


The Interstellar Boundary Explorer, or IBEX, is a relatively small spacecraft, compared to others. It has eight sides plus a top and bottom. The sides are not all the same length, like for a stop sign. Some of the sides are longer than others. IBEX is thirty-eight inches (or approximately one meter) wide, twenty inches (or approximately one-half meter) tall, and weighs around three hundred seventy-five pounds.

Here, we describe the various parts of the IBEX spacecraft. You can read about them in order or move from heading to heading.

All around IBEX: Multilayer insulating material

Much of IBEX is wrapped in several layers of dark-colored insulation, called the Multilayer Insulating Material. These layers reflect heat from the Sun so that IBEX does not get too hot, and they also hold in heat to keep the spacecraft's internal parts from getting too cold. This insulation is similar in texture to aluminum foil. Sticking out from the insulation on the top, sides, and bottom are several other parts of IBEX described here.

Top side: Solar panels, thrusters, and antennae

The top of the spacecraft is mostly covered with solar panels. IBEX uses solar panels to collect energy from the Sun. The Sun is the power source for the IBEX spacecraft. These solar panels are composed of a thin wafer-like smooth metallic material made of individual pieces that are roughly rectangular in shape and a few inches (or several centimeters) square in area. The solar panel pieces are arranged in rows. In between several of the rows are small circular metallic screws that help to hold IBEX together.

In the center of IBEX's top is a small cone shaped metal object, one of IBEX's main thrusters. Thrusters are small rocket engines. IBEX has several cone and cylinder-shaped thrusters located on various parts of the spacecraft that are used periodically to correct IBEX's orbit and the rate that it spins, and they move IBEX so its solar panels always point toward the Sun.

Also located on the top of IBEX and offset to one side is the tube-shaped antenna. IBEX uses antennae to send information from the spacecraft to controllers on the ground, and to periodically receive new commands and information. This antenna is about one foot (or one-third meter) long and a few inches (several centimeters) wide.

Side Panels

Now, we will introduce you to the pieces that make up the sides of the IBEX spacecraft.

First side panel: Propellant tank

On one side of IBEX, you will find a semicircular metal object partially sticking out from the craft. This is a spherical propellant tank, containing some of the fuel for IBEX's thrusters. Most of the propellant tank is located inside IBEX so only part of it protrudes outward. Above the propellant tank are two small cylinder-shaped objects. These are two of IBEX's four small thrusters.

We will use this side of IBEX containing the propellant tank as the first side, and describe the rest of the sides compared to the location of this one.

Second side panel: Radiators

To the right of the propellant tank on the second side is more multilayer insulation. In the middle of the insulation is a rectangle of smooth flat metal that is about ten inches (or one-quarter meter) long and about eight inches (or just under one-quarter meter) wide. This is one of IBEX's radiators. Because fans cannot work without air, IBEX cannot use fans to keep cool in space. Heat that builds up inside the spacecraft is transmitted through special metal panels on the outside of IBEX. These panels then emit that heat energy out into space.

Third side panel: IBEX-Lo

On the third side, to the right of the radiator panel, is IBEX-Lo. IBEX-Lo is a large circular sensor that collects energetic neutral atoms in eight different energy bands. IBEX-Lo sorts the particles and keeps track of their direction, entry time, their masses, and each particle's energy. IBEX-Lo is large, almost twenty inches (or almost one-half meter) in diameter. It is made of a gold-colored smooth metal and looks like a large wheel partially sticking out of the side of IBEX.

Fourth side panel: Another radiator

On the fourth side, to the right of IBEX-Lo, is another radiator panel. This one is a little larger than the one described previously and is shaped like the letter L.

Fifth side panel: Another propellant tank

On the fifth side directly opposite the side containing the first propellant tank is another propellant tank. This side of IBEX looks almost exactly like the first side, with two small thrusters located above the propellant tank near the top of IBEX.

Sixth side panel: More radiators

On the sixth side of the spacecraft are two more radiator panels, each one a little smaller than the first radiator panel described previously.

Seventh side panel: IBEX-Hi

On the seventh side, to the right of the two radiator panels, is IBEX-Hi. IBEX-Hi is a sensor that collects energetic neutral atoms in six different energy bands. IBEX-Hi sorts the particles and keeps track of their direction, entry time, and each particle's energy. IBEX-Hi is also gold-colored and shaped like a wheel. It is a little larger than IBEX-Lo.

Bottom side: Star tracker, thrust tube and antenna

Finally, we get to the bottom of IBEX. Just below the side of IBEX that has the L-shaped radiator panel is the star tracker. The star tracker is roughly shaped like a squat pyramid and mostly covered in multilayer insulation with a little camera that points out into space. The star tracker uses known positions of various stars all around the sky to figure out the direction the IBEX spacecraft is pointing.

In the middle of the bottom of IBEX is a large hole about fifteen inches (or about one-third meter) in diameter. When IBEX launched, it included an extra rocket that fired to get IBEX to its high altitude. When this rocket was done firing, it was jettisoned into space. The spacecraft ring, or hole, that remained is known as the "thrust tube". This hole does not extend all the way through IBEX to the top. This is only a hemisphere-shaped empty area.

Offset on one side of the thrust tube is another antenna that IBEX also uses for communication. This antenna is cylinder shaped and is a little shorter and wider than the antenna on the top of the spacecraft.

Thank you for taking a spin around IBEX with us. We hope you have enjoyed learning about our small -but important- spacecraft!

To learn more

To learn more about NASA's Interstellar Boundary Explorer (IBEX) mission go to html://

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