News>Taxpayers, space community benefit from innovative “ESPA” ring adapter
A computer-generated picture of the ESPA ring also shows the booster adapter and the five satellites that will be deployed during the initial STP-1 launch this fall. (Illustration courtesy of Department of Defense Space Test Program)
This computer-generated picture depicts an Integrated Payload Stack (IPS), including the largest satellite, ESPA ring and five smaller satellites. (Illustration courtesy of Department of Defense Space Test Program)
by Jo Adail Stephenson
Space and Missile Systems Center Public Affairs
6/19/2006 - LOS ANGELES AIR FORCE BASE, Calif. -- In the midst of budget cuts and space program cost overruns, the Air Force has innovatively come up with a way to save taxpayers money and at the same time increase small satellite launch capability to its maximum potential.
It’s called the Evolved Expendable Launch Vehicle Secondary Payload Adapter, or ESPA ring.
Roughly five feet in diameter and two feet tall, the ESPA is a half-inch thick aluminum ring on which individual satellites can be mounted on one of six standardized secondary satellite mounting locations found on the ring’s perimeter. It can support up to six 400-pound satellites.
This means that instead of launching one satellite with one rocket, the ESPA ring, which fits in between the rocket and the largest satellite, will enable that same launch vehicle to carry up to six additional small satellites for the cost of one launch.
Col. Joseph Boyle, the Space and Missile Systems Center’s chief launch engineer, says this could capture a whole new market for the EELV program and provide a significant boost to the research community for the nation.
In the near future, the ESPA ring will allow a number of EELV launches to have the capacity to offer the small satellite community this significant new access to space option. This could substantially reduce integration costs from an estimated $20 million per satellite per launch to $5 million. The launch costs, which are figured separately from the integration costs, are still being worked, according to SMC EELV program officials.
“We are looking at putting ESPA rings on as many Air Force launches as we possibly can,“ said Lt. Col. Dan Griffith, director of the Department of Defense Space Test Program (STP); part of the Air Force Space and Missile Systems Center’s Detachment 12 at Kirtland Air Force Base, N.M.
The STP-1 launch, slated for fall this year, will be the inaugural flight of the ESPA ring. The mission’s manifest is the Defense Advanced Research Projects Agency’s Orbital Express, the launch’s largest satellite, and the ESPA ring with five auxiliary satellites – MidSTAR-1 (Naval Academy); FalconSAT-3 (U.S. Air Force Academy); NPSAT1 (Naval Post Graduate School); STPSat-1 (STP built with Naval and Air Force Research Laboratory experiments) and CFESat (Los Alamos National Laboratories).
Aboard an Atlas V launch vehicle for this first mission, a total of six distinctly different satellites at two different altitudes/inclinations make this an important first launch of its kind, according to Colonel Griffith.
From STP’s perspective, the second ESPA flight’s prospects are outstanding. “There is a lot of interest in ESPA across the space community and the interest is growing. It was designed primarily with the science and technology community in mind, but there are very obvious potential applications if you have a small operational satellite. No reason why they could not use an ESPA ring,” Colonel Griffith said.
Other government agencies, universities and commercial space organizations, along with the Air Force, can take advantage of this new small satellite launch capability.
Through STP’s partnership with NASA, ESPA is also being considered for use on NASA missions, according to Colonel Griffith.
The ESPA ring was a joint initiative between the SMC Detachment 12 STP contingency and the AFRL Space Vehicles Directorate. STP worked on the ESPA ring with AFRL under a small business innovative research contract that AFRL had with CSA Engineering in Mountain View, Calif.
A DoD program with the Air Force as the executive agent, STP serves as the primary provider of spaceflight for the entire DoD space science and technology community and provides mission design studies, satellite/launch vehicle acquisition, and on-orbit operations for DoD experiments as required.
The Space and Missile Systems Center is the technical center of excellence for researching, developing and acquiring military space systems.