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932,000 miles

After IMAP lifts off from Florida, the spacecraft will begin a nearly four-month journey over 932,000 miles (1.5 million kilometers) to a location in space that called Lagrange Point 1 (L1)—roughly 1% of the way from Earth to the Sun. It’s a sort of parking lot in space where a spacecraft can maintain its position without using a lot of fuel.

IDEX will start its work before that. Several weeks after launch, the instrument will flip open its door and begin preparing to collect dust.

Image: Artist's depiction of the IMAP spacecraft. (Credit: NASA/Princeton University/Patrick McPike)

43 particles

Interstellar dust continually flows into our solar system, moving in a single direction like a current. Astronomer Carl Sagan referenced this material in his famous quote, “The cosmos is within us. We are made of star-stuff.” Most of this dust has likely been destroyed and recondensed multiple times over its journey, Horányi said.

To date, scientists have only detected and analyzed 43 grains of interstellar material, in addition to a handful of candidate grains found embedded in meteorites. IDEX will be entering a mostly uncharted territory.

“Every single grain has a high level of importance to us,” Horányi said.

When these particles zip into the instrument, they will smack into a target at its back, instantly vaporizing into a puff of neutral elements, electrons and ions. IDEX will analyze the ions from each impact, identifying the materials that make up the dust. That may include minerals rich in elements like silica, magnesium, and iron, and possibly larger organic molecules.

Image: Graphic of the heliosphere, a bubble in space created as the solar wind flows away from the sun. (Credit: NASA/IBEX/Adler Planetarium)

16.15 inches

To capture interstellar dust, the IDEX team developed the largest instrument of this kind. IDEX weighs about 47 pounds. Its opening measures more than 20 inches across, and the target at its back is 16.15 inches wide.

Altogether, the IDEX team estimates that it could collect around 100 grains of interstellar dust every year during the first two years of the primary IMAP mission.

IDEX comes from a long line of dust instruments built by LASP. They include the Europa (SUDA), which launched for Jupiter’s moon Europa last year aboard NASA’s Europa Clipper spacecraft.

Scott Tucker, project manager for IDEX, noted that the instrument will also collect grains of interplanetary dust, or material shed from comets and asteroids in our solar system. These particles move a lot slower than stardust, so he and his colleagues designed the instrument to accommodate a wide range of impacts—which required careful design of IDEX’s electronics.

“We want to measure things that are small and not very fast, and things that are bigger and very fast,” said Tucker, director of engineering at LASP.

Image: IDEX with its door open. (Credit: ���Ҵ�ý�ƽ������/Patrick Campbell)

248 degrees Fahrenheit

In some cases, particles of dust may leave residue behind when they vaporize on the IDEX target, which could contaminate future data—a bit like gunk on a car windshield. ��

The instrument team has a solution: The group will periodically raise the temperature of the IDEX target to 248 degrees Fahrenheit, burning away most of that residue. The target itself is coated in a layer of ultra-pure gold roughly 5 microns thick, or a little thicker than a human red blood cell.

“The target is going to be maintained to remain pristine, good as new again and again,” Horányi said.��

Image: Mechanical engineer Tim Hellickson inspects the gold-coated impact target for IDEX. (Credit: LASP/���Ҵ�ý�ƽ������)��

87 names

It took a large team to make IDEX a reality, including professional scientists and engineers, and many students. When the instrument launches, it will carry a plaque with the names of 87 of these team members—although Horányi estimates that closer to 100 people participated in the IDEX project.

Tucker and Horányi will be part of a contingent from LASP attending the launch in Florida.

“IDEX is going to be a whole different chapter in our ability to do these types of measurements, Horányi said. “I can hardly wait to look at the first impact.”

Image: Members of the IDEX team celebrate their first dust impact. The group tested IDEX by smashing particles of dust into its target using an accelerator at the Institute for Modeling Plasma, Atmospheres, and Cosmic Dust (IMPACT) lab on campus. (Credit: LASP/���Ҵ�ý�ƽ������/Chip Bollendonk)