University of California, Riverside

UCR Newsroom

Physicist Part of NASA Project Team

UCR Scientist Part of Project Team Accepted to NASA’s Small Explorer Program

Physicist Gary Zank part of IBEX team that will capture images of the boundary
between the solar wind and interstellar space

(February 3, 2005)

Gary ZankEnlarge

Gary Zank

RIVERSIDE, Calif. — — Astrophysicist Gary Zank is part of a scientific team developing the Interstellar Boundary Explorer (IBEX), a satellite that will make the first map of the boundary between the Solar System and interstellar space, and which has been selected as part of NASA's Small Explorer program (SMEX).

It is the first mission designed to detect the edge of the Solar System. As the solar wind from the sun flows out beyond Pluto, it collides with the material between the stars, forming a shock front. IBEX contains two neutral atom imagers designed to detect particles from the termination shock at the boundary between the Solar System and interstellar space.

“Gary Zank and his team at UC Riverside study the theory and modeling of the heliosphere and they’re one of the world’s best,” said David McComas of the Southwest Research Institute in San Antonio, the leader of the $134-million IBEX mission, scheduled to launch in 2008.

“We’re essentially providing the models and theory underpinning the mission,” said Zank, who is the director of the Institute of Geophysics and Planetary Physics (IGPP) at UCR. “Over the past 10 years we’ve developed the models of the boundary between the solar wind with the interstellar medium.”

Much of the interstellar boundary is only understood as predictions based on theoretical models such as those developed by Zank. Among the predictions IBEX is expected to confirm or refute is the existence of the hydrogen wall — a boundary comprised of piled-up hydrogen atoms and protons.

IBEX will also study galactic cosmic rays, energetic particles from beyond the Solar System that pose a health and safety hazard for humans exploring beyond the earth’s orbit. IBEX will make these observations from a highly elliptical orbit that takes it beyond the interference of the Earth's magnetosphere.

IBEX was selected from among 29 SMEX and eight mission-of-opportunity proposals submitted to NASA in May 2003. They were in response to an Explorer Program Announcement of Opportunity issued in February 2003. NASA selected six proposals in November 2003 for detailed feasibility studies.

“Explorer missions continue to efficiently address NASA's objectives, because of the competitive character of the Explorer Program,” said Ghassem Asrar, NASA's Deputy Associate Administrator for the Science Mission Directorate. “Dr. McComas and his co-investigators submitted a compelling proposal. It had sufficient details to convince other independent scientists, engineers, technologists, cost analysts, and program managers this is an exciting and breakthrough experiment for NASA to sponsor.”

NASA’s Small Explorer program (SMEX) consists of rapid, small, and focused science exploration missions.

The Explorer Program is designed to provide frequent, low-cost access to space for physics and astronomy missions with small to mid-sized spacecraft. NASA has successfully launched six SMEX missions since 1992. Funded by NASA, for up to $450,000 each, these studies focus on cost, management, and technical plans, including small business involvement and educational outreach. NASA's Goddard Space Flight Center in Greenbelt, Md., manages the Explorer Program for the Science Mission Directorate.

Following NASA’s Jan. 26 announcement of the selection of IBEX, Zank and his team at UCR began developing models of what the explorer might encounter to test the instrumentation developed by other members of the team.

“This is a mission that will both validate many aspects of our models and also will tell us what areas we have to look to in future explorations,” said Zank
The heliosphere

The heliosphere

The University of California, Riverside ( is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California's diverse culture, UCR's enrollment has exceeded 21,000 students. The campus opened a medical school in 2013 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Center. The campus has an annual statewide economic impact of more than $1 billion.

A broadcast studio with fiber cable to the AT&T Hollywood hub is available for live or taped interviews. UCR also has ISDN for radio interviews. To learn more, call (951) UCR-NEWS.

More Information 

General Campus Information

University of California, Riverside
900 University Ave.
Riverside, CA 92521
Tel: (951) 827-1012

Department Information

Media Relations
900 University Avenue
1156 Hinderaker Hall
Riverside, CA 92521

Tel: (951) 827-6397 (951) UCR-NEWS
Fax: (951) 827-5008

Related Links