Modular Insertion Stage (MIS)

The Modular Insertion Stage (MIS) was conceived as a very low cost, expendable, liquid propellant upper stage which could meet all user needs for expendable upper stages. The "modular" portion of the name means MIS could be assembled to match whatever requirement the user has for an upper stage. MIS could be assembled as a small 5000-pound gross weight stage with a single engine, for boosting small payloads to orbit from a reusable launch vehicle. It could also be configured as a 30,000-pound gross weight stage with three engines for EELV medium class payloads.

The original impetus for MIS was two fold. The first of these was the desire to build a stage more cheaply than could be done assembling $1 million+ solid rocket motors for GTO/GEO missions. The second was to have flexibility to perform multiple burns using the same engine, as well as being able to throttle the engine to optimize stage performance. Liquid upper stages also have the potential to provide higher performance than solid propellant motors. This is offset however, by the very high propellant fraction offered by solid stages, which can approach 95 percent propellant mass fraction.

Air Force Research Lab (AFRL), then Phillips Lab, awarded two study contracts in 1997 to TRW and Rocketdyne to determine which propellants were most suitable for MIS. Requirements for MIS included long term storability with propellants loaded and no use of toxic or carcinogenic propellants. The studies concluded hydrogen peroxide and kerosene propellants best met those requirements. The two industry studies indicated that a recurring cost goal of $800,000 was possible.

With these study results in hand, AFRL personnel worked with NASA's Marshall Space Flight Center (MSFC) to determine the best way to develop and demonstrate MIS technologies. Marshall's Bantam low cost lift program provided a suitable contract vehicle, and it was agreed that MSFC would provide program management and contracting support, and AFRL would provide technical oversight and funding from congressional adds. Orbital Sciences Corp (OSC) won the initial MIS technology demonstration contract through NASA Research Announcement 8-19. MSFC determined that the OSC program was sufficiently synergistic with its Bantam goals and provided $1.0 million to supplement the Air Force $4.0 million. $8.7 million of Current as of November 2002 Congressional Add funding was also provided.

The MIS technology demonstrator program was named the Upper Stage Flight Experiment (USFE), and planned for flight demonstration from the Kodiak Launch Complex (KLC) in June 2000. The USFE program was structured to develop two key technologies through a series of ground demonstrations, and then incorporate those key technologies into a suborbital flight demonstration.

The two key technologies were:

1. A 10,000-pound thrust, pressure fed 90 percent concentration hydrogen peroxide/JP-8 fueled rocket engine.
2. An integral common bulkhead design composite stage/tank structure.

USFE's suborbital flight demonstration was planned for initial boost by a modified Orbital/Suborbital (OSP) vehicle.

No congressional add money was received in Fiscal Year 1999. MSFC and AFRL provided approximately $3.5 million of additional funding to continue the technology development. $15 million of Congressional Add funding was received in Fiscal Year 2000, and $6 million in Fiscal Year 2001, which was sufficient to complete construction of the USFE stage and ground test it at NASA Stennis Space Center. This testing is currently scheduled for May 2003. No additional funding was received in 2002, and there is currently insufficient funding for a flight test from KLC.

Technology firsts for the USFE program include the first new hydrogen peroxide engine to be built and test fired since the 1960's, the first common bulkhead design composite propellant tank, and the first demonstration of an entirely new stage and engine built for less than $20 million.

MIS and USFE demonstrate the possibility of building upper stages for much less than the tens of millions of dollars EELV upper stages currently cost. For both expendable launch vehicles and future Military Spaceplane system use, MIS can provide both significant cost savings, and increased capability compared to either solidbased or current liquid upper stages.