This is a collection of images of the Orbiting Astronomical Observatory-A2, people involved in its operation, and researchers who used it. OAO-A2 contained two research components to study the sky in the ultraviolet: the University of Wisconsin's Wisconsin Experiment Package (WEP) and the Smithsonian Astrophysical Observatory's Celescope. The WEP contained a nebular photometer, two spectrographs, and four stellar photometers. Celescope contained four ultraviolet-sensitive television cameras. OAO-A2 was launched on December 7, 1968, and was turned off, following the failure of the high-voltage power supply for the WEP, on February 13, 1973.

Because my role was with Wisconsin, many of the photos I have deal with WEP and its people. Mike Molnar provided some of the images, some are official NASA photos, Otis Brown and Jim Valenti each took one, and I took the others.

There is a web page at Wisconsin's Space Astronomy Lab, I think created by Marilyn Meade, that has a more information about the observatory.

PRE-LAUNCH


An artist's conception of the observatory in orbit Another artist's concept

OAO-A2 with solar arrays extended

OAO-A2 with its shroud

Side view of an engineering unit for a WEP photometer
(Text book added to give scale)

Front view of an engineering unit for a WEP photometer
(Text book added to give scale)


LAUNCH NIGHT AT WISCONSIN

Mike Molnar took the following photos at Wisconsin's Space Astronomy Laboratory on Park Street while waiting to OAO-A2 to be launched.


Ya-Yue Van

Dave Ward, Al Holm, Ya-Yue Van, Dave Jenner, and Skip Schiffer

An employee of the Space Astronomy Laboratory
with a blackboard showing key launch events


Atlas-Centaur carrying OAO-A2 into orbit
Image from http://www.sal.wisc.edu/OAO/

Al Holm, Ya-Yue Van, Dave Jenner, Carol Burkhalter
and Don Michalski toasting a successful launch


AFTER LAUNCH


Building 3/14, OAO's home at Goddard, at sunrise
Photo taken by Otis Brown from his plane

NASA publicity photo of science instrument staff
Dr. Lillie, Hugh Brown, Otis Brown, and two SAO staff members

NASA publicity photo of OAO-2 staff
Dr. Lillie, Dr. John McNall, and Fred Chiccone

The OAO-A2 operations staff


1971 3-YEAR ANNIVERSARY


Grumman's Superstar Poster

Anniversary Party photo (from Jim Valenti)

We can identify a few of the people in this image. Jim Harrison (Grumman) is standing at the back. Jim Gemmell (NASA/GSFC) is standing in front of Jim Harrison and looking away from the camera. Barbara Danieli (WEP) is the woman with blond hair to the right of Jim Gemmell. The face of Al Boggess (NASA/GSFC) looking at the camera can just be seen near the right edge of the photo.


PHOTOS OF THE OPERATIONS STAFF AND AREAS BY MIKE MOLNAR


Al Holm at work in the WEP office in 1971

Grumman's analysis office

Milestones plaques

Flight control consoles

Computers

More computers

WEP Ground Operations Equipment (GOE)

OAO-A2 spacecraft operations status board


MORE PHOTOS OF THE OPERATIONS STAFF AND AREAS


George “Big George” Fredricks at a 360-65 printer - Jan 1972

Bob Leone, POC


OAO-A2 control center with Grumman staff
Joseph Blazosky provided the following identifications and information.

Seated staff members at the consoles in the control center include, left to right, in the back row Ed Slabinski, Tom Keely, and Jim Young. In the front row are John Danner and Bob Leone. The standing man may be a Contact Controller. The big board in front displays telemetry giving the spacecraft's status. In the back is the Wisconsin GOE.

The front row positions were responsible for Stabilization and Control and for Power. The back row, left to right, was the Spacecraft Controller, the Project Operations Controller (POC), and the Ground Controller. The Spacecraft Controller monitored the command memory operation and other subsystems not covered by the front row. The POC was the team leader and in overall control of the spacecraft. The Ground Controller handled all of the commanding and interface with the ground station personnel and the CCPS support staff running the SDS 930’s in the back room. “Ultimately as the spacecraft got older and budgets diminished, we cut back to three people manning the consoles. The Ground Controller, the POC and the Spacecraft controller who monitored all of the subsystems and command memory execution. Occasionally we ran with two people; the Ground Controller and the POC who monitored everything. Those were interesting times.”


The OAO-A2 status board

SAO Camera 1 image taken at Rosman16163 to try to see Cen XR-3

Otis Brown with WEP GOE - Jan 1972


END OF MISSION


OAO-A2 Status Board on February 14, 1973
OAO-A2: 22,000 orbits; Launched Dec 7, 1968; Turned off Feb 13, 1973

WEP crew after turn-off, Feb 14, 1973: Data tech Sandy Howard,
Charlie Wu, Al Holm, Dave Gottlieb, and Hugh Brown


PHOTOS FROM TWO PARTIES AT THE WEP APARTMENT AT BRAEBROOK

We held two parties at the Wisconsin apartment at Braebrook Village, across the street from Goddard. One was in 1972 when Charlie Wu’s girl friend, Liz, got her visa and was able to return from Canada. The other was at the end of mission, when we celebrated OAO’s accomplishments with a rehoboam of champagne as the centerpiece.

Gail (now my wife), Liz (now Charlie’s wife), and Charlie Wu

Rosemarie of SCPS, and Gail at the WEP apartment

Wayne Putnam of Grumman

Jean and Bob Peca of WEP

Sara Hunt of SCPS at the end of mission celebration


WEP Radiometric Calibration

Very important for the scientific results from the WEP instruments was being able to establish absolute fluxes from the measured count rates. This was done by using sounding rockets to measure the fluxes of three stars, Alpha Virginis, Eta Ursa Majoris, and Alpha Leonis. Then, by measuring the count rates the instruments determined for these three stars it was possible to transfer the calibration to the instruments and, hence, to other observed targets.

The sounding rocket instruments were calibrated before and after the flight by measuring their response to synchrotron radiation from an electron storage ring at Stoughton, Wisconsin. Physicist Tim Fairchild was the leader in this effort. I took the following photos when I assisted in an unsuccessful effort in 1976 to refine the calibration.

Tim Fairchild installing the detector at Stoughton

Fairchild at one of the Synchrotron Storage Ring lines

Our 1976 Aerobee rocket with payload in horizontal test,
making sure that pitch and yaw are properly connected

The Aerobee launch tower at White Sands


The our Aerobee on the rails in the launch tower

A night launch - This was Ralph Bohlin’s 13.073, not Wisconsin’s


Pioneering Science

All the science results from OAO-2 were pioneering. Celescope surveyed 10% of the sky in the UV, and published a catalog of sources it found. WEP was used to observed Earth’ss atmosphere, the Moon, planets, comets, zodiacal light, hot stars, cool stars, variable stars, planetary nebulae, interstellar gas and dust, globular clusters, and galaxies. A symposium was held at the University of Massachusetts that resulted in a publication with early 600 pages of data, analysis, and theory. Over 130 publications were based on and inspired by the WEP data.

Papers presented at the OAO-2 symposium

Catalog of UV sources in 10% of the sky

Location of observations made by WEP

Location of exposures made by Celescope



Prepared by Al Holm, 2 May 2017; updated 15 Nov 2018