The Johns Hopkins Gazette: November 17, 1997
Nov. 17, 1997
VOL. 27, NO. 12


Crocker To Head Research At CAS

Nationally known engineer led team in fixing Hubble optics

Emil Venere
News and Information

Johns Hopkins Gazette Online Edition

The university has appointed an internationally known engineer to head up research at the Center for Astrophysical Sciences and to help Hopkins compete for shrinking federal funding.

James H. Crocker officially filled the position on Oct. 27. He is the first associate director of research for CAS, which was created in 1985 to support and oversee large astrophysics projects at Hopkins.

An electrical and systems engineer by training, Crocker spent 10 years at the Space Telescope Science Institute, where he led a team of scientists in repairing the Hubble Space Telescope's flawed optics in 1994.

Most recently, he has managed programs for an international project to build the largest telescope in the world. Dubbed the Very Large Telescope, it is actually a collection of several telescopes being constructed by the European Southern Observatory in Chile's Atacama Desert.

"He brings an unusual combination of a great deal of experience with large ground-based programs and a great deal of experience with space-based instrumentation," says CAS director Holland Ford, a professor in the Department of Physics and Astronomy. "It's unusual to find people who have been very successful in both fields."

Ford worked closely with Crocker on the Hubble repair mission and on an advanced camera that is to be installed in the space telescope in 1999.

Considering Hopkins' exemplary track record in astrophysics over the years, it was important to hire a savvy research director to keep the university on track, he says.

"We are very strong in astrophysics, and we're very strong in space science, and we want to continue that strength in the face of either steady or declining budgets and increased competition," Ford says.

For example, it is clear that NASA will be awarding a large number of future grants and contracts for work related to the next-generation space telescope, which is to replace the Hubble during the first decade of the 21st century. The space agency also is expected to concentrate funding on its Origins program, research encompassing everything from the genesis of stars and galaxies to the emergence of life and the beginning of the universe.

"We have to be forward-looking and begin to make preparations so that we can compete for those projects," Ford says.

Crocker is well-acquainted with plans for the next-generation space telescope. It calls for an ambitious new approach, the assembly in space of a large mirror, a reflecting surface possibly three times the size of Hubble's 2.4-meter mirror.

"If we can put something on the order of 6 or 8 meters in space, we can do incredible astronomy and astrophysics," Crocker says.

The largest telescope on Earth has a 10-meter mirror. But putting something nearly that large in space, above the light-distorting atmosphere, would lead to a plethora of discoveries. Such an instrument might even enable astronomers to find evidence for Earth-like planets orbiting nearby stars.

But it's not possible to loft a telescope that large into orbit. Instead, the mirror would have to be launched as a sort of kit, robotically assembling itself in space.

Learning how to accomplish that technological feat would pave the way for a future space telescope truly capable of detecting oxygen in the atmospheres of planets orbiting other suns, finally answering the question of whether nearby solar systems harbor life. It would take a 25-meter telescope to see that well, Crocker says.

"We are talking about something that would unfold and align, which is a very difficult problem," he says. "You want to take a 25-meter mirror, chop it up into little 1-meter pieces, stack the potato chips up like in a Pringle can, launch it into space, and then somehow assemble these potato chips into an optical surface that is accurate to less than a hundredth the thickness of a human hair.

"A non-trivial problem. You don't want to do that on a 25-meter telescope first. You'd like to do it on an 8-meter first."

The third-generation space telescope could be operating by 2025, and Hopkins scientists hope to be actively involved. For the time being, however, Crocker will be focusing most of his attention on an international project called the Sloan Digital Sky Survey.

"It's about doing something that has never really been done before, making a three-dimensional map of the universe, so we can finally see what the universe really looks like," he says.

"Probably 50 years from now, when they look back at astronomy in the first part of the 21st century, this will be sort of the defining event. It's a big deal."

Astronomers will produce the survey using a new observatory in south-central New Mexico. They expect to begin operating the 2.5-meter telescope in about a year.

Hopkins scientists are playing a dual role: They designed and built the telescope's spectrographs, and they will create a digital science archive of the sky survey observations. The archive eventually will make the volumes of information available to scientists and schoolchildren alike.

Crocker has recently been named associate director of the sky survey, and the project office is being moved here, from its former location at the University of Chicago.

"Hopkins is a great place to do astronomy," Crocker says. "I think there is a synergism here that hasn't yet been fully exploited."