MightySat I Deployed From Shuttle

EL SEGUNDO, Calif. (12/2198) -- Aerospace Corporation engineer Robert Davis reported that MightySat I, a tiny but ambitious experimental satellite, began communicating with researchers at Kirtland Air Force Base, Albuquerque, within an hour after being deployed on Dec. 14 by the shuttle Endeavor. "It's doing super," said Davis on Friday, Dec. 18. "We've turned on a couple of the experiments and all the systems on board are operating."

Weighing in at a scant 140 pounds but comprising five separate experiments, MightySat 1 may be the smallest, least expensive and most efficient satellite every developed with The Aerospace Corporation's support, said Davis, a project engineer in the company's Space Technology Directorate in Albuquerque.

Davis has been the systems engineer on MightySat since the program's inception in June 1995. The hexagonal-shaped spacecraft, roughly the size of a standard two-drawer filing cabinet, is a product of the Air Force Research Laboratory (AFRL) to which The Aerospace Corporation provides engineering and scientific support. MightySat I is the first in a series of low-cost miniature test satellites in development by the Air Force.

Composite Bus

One of the experiments involves the first composite satellite bus, or chassis, to be launched from the shuttle.

"It makes up most of the MightySat I satellite," said 1st Lt. Barbara Braun of AFRL's Space Vehicles Directorate. "Extremely strong, it weighs a mere 17 pounds compared with the 32-pound aluminum counterpart typically used. And less weight means lower launch costs, always an important consideration in our business."

In addition to the composite bus, MightySat I hosts four other experimental payloads: high-performance, multijunction solar cells; low-shock, shape-memory release devices; a suite of advanced electronics packaging technologies; and a microparticle impact detector.

Davis explained that testing advanced technologies such as solar cells, batteries and structures on low-cost MightySat platforms not only provides valuable performance data but also reduces the risk when applying those technologies in larger operational satellites.

Real-World Applications

"The whole point is to transition our AFRL technologies from the lab to the real world," said Davis. "These technologies have the potential to enhance performance or reduce cost for operational satellites such as SBIRS (Space-Based Infrared System), NPOESS (National Polar-Orbiting Operational Environmental Satellite System) or the next generation of communications satellites."

MightySat I was created to serve as a single-mission pathfinder for a long-term series of demonstration missions. A contract for MightySat II was awarded early in 1996 to develop a spacecraft that could be used in up to five technology demonstration missions over an eight-year period, Davis said.

The first MightySat II satellite is in fabrication, with an expected launch date of January 2000. Pete Thomas, project engineer in the Space Technology Directorate, leads The Aerospace Corporation's support for this mission, which will host 10 technology demonstrations.

A unique aspect of the Mighty Sat program is the large degree of government involvement in the development of the space vehicle. The MightySat I spacecraft bus, without payloads, was delivered by the developing contractor to Kirtland in late 1996.

A Team Effort

A small team of Air Force officers, Aerospace Corporation engineers, and technicians from an on-site systems engineering and technical assistance contractor (better known as a SETA), assumed full responsibility for the satellite. After thoroughly testing the spacecraft interfaces, the team integrated the five advanced technology payloads developed within AFRL.

When the satellite was fully assembled, the government team designed and executed a series of environmental tests, subjecting the vehicle to the expected dynamic and thermal conditions of launch and on-orbit operations. Most of the testing was performed completely by the Air Force-Aerospace Corporation team, with little involvement by the spacecraft bus contractor.

At a total program cost of $6 million, Davis called MightySat I one of the lowest cost, free-flying satellites ever built by the Air Force, and he credited a cadre of Aerospace Corporation experts with keeping costs down.

Vigilant About Expenses

"Given our tight budget, we've really had to be vigilant about our expenses," he explained. "The program has received tremendous value through our immediate access to a variety of experts in the Engineering and Technology Group. They have provided critical support to satellite development efforts in a highly efficient manner, making wide-ranging Aerospace Corporation support affordable to the program."

Dr. Geoff Smit of the Space Systems Evaluation Department played a critical role in the design of the attitude determination and control system for both MightySat I and MightySat II. Dr. Smit is developing attitude determination software that will be used by MightySat I operators during on-orbit operations.

Dr. Boyd Carter of the Energy Technology Department led a group that performed extensive testing of MightySat I nickel-cadmium batteries. This resulted in the first-ever qualification of commercial cells for flight on a shuttle secondary payload.

Dr. Mike Stallard of the Space Technology Directorate was the lead engineer for the development of fully composite structures for MightySat I and MightySat II and was responsible for the successful vibration testing of MightySat I.