Avionics key in drive to cut space launch costs
By John Rhea
WASHINGTON - Proven avionics designs from past space projects will be major factors in holding down costs of a new reusable unmanned spacecraft under development at the Lockheed Martin Skunk Works in Palmdale, Calif.
This is the word from Jerry Rising, executive vice president of the Skunk Works development site and program manager for the half-scale X-33 demonstrator vehicle and the operational vehicle to be known as the VentureStar.
The principal avionics subcontractor on the X-33 program, AlliedSignal Aerospace Guidance & Control Systems division in Teterboro, N.J., is using such proven commercial off-the-shelf (COTS) technologies as the 1553 serial databus, PowerPC 603e microprocessors, and 6U VME backplanes. Rising also cites microelectronics technologies developed at the Jet Propulsion Laboratory in Pasadena, Calif., as applicable to the X-33.
VentureStar, a $5 billion investment, is to begin operations in 2004. The program consists of two operational vehicles and two launch-and-recovery sites to be chosen later in the program.
Development of the new spacecraft is to begin in 2000 if the X-33 test program is successful, Rising said during a Lockheed Martin technology briefing at the National Press Club in Washington last month. The first flight of that vehicle, however, has slipped six months to December 1999 because of difficulties with the advanced- design rocket engines from the Boeing Rocketdyne Division in Canoga Park, Calif.
VentureStar is to cut the cost of delivering a pound of payload to low Earth orbit by an order of magnitude. Primary aims are to reduce launch costs of commercial satellites and to service the future International Space Station. The operating costs for a pound to low orbit for NASA`s Space Shuttle run about $10,000, Rising estimates.
Rising says he expects to drive that cost down to $1,000 per pound to low orbit by using many of the Shuttle techniques, such as vertical launch and horizontal landing, liquid hydrogen/liquid oxygen propulsion, as well as by using COTS avionics.
The X-33 and VentureStar are designed from the beginning for unmanned operations, thus avoiding the excessive costs of man-rating the components, particularly the electronic components. Rising points out that the X-33 is designed for automated operations based on pre-programmed flight profiles, while the VentureStar will use advanced techniques for autonomous operations that may include spontaneous tasks.
Tooling should be completed for the 273,000-pound, 69-foot X-33 demonstrator vehicle by next month, Rising says, and final assembly is set for July.
A test program of 15 suborbital overland flights is planned from Edwards Air Force Base, Calif., near the Skunk Works site, going 450 miles to Michael Army Air Field, Utah, and 950 miles to Malmstrom Air Force Base, Mont. The test vehicle is expected to reach speeds of Mach 13.8 at altitudes of 300,000 feet.
The 144-foot, 2.6 million-pound VentureStar will be able to carry a payload of more than 50,000 pounds to low orbit, 25,000 pounds to the space station, or 18,000 pounds to geosynchronous orbit, Rising says. With two operational vehicles, Lockheed Martin officials hope to fly 40 missions a year and achieve a service life of 100 missions per vehicle. The entire four-vehicle Space Shuttle fleet, which began operations in 1981, is not due to fly its 100th mission until sometime next year.
Rising estimates that VentureStar spacecraft should be able to capture 25 percent of the market to service the space station and 5 percent of the existing U.S. Defense Department and NASA launches. Still to be determined is how much of the commercial market Lockheed Martin can win away from expendable launch vehicles in the United States and overseas.
The X-33 program, initiated in 1996, has cost about $760 million to date, of which NASA is paying 80 percent and the Lockheed Martin team the balance. Rising estimates the cost of the vehicle itself at about $360 million.
As part of the follow-on VentureStar program, Lockheed Martin will select two launch and recovery sites. To date, 31 locations in 14 states have been proposed. Unlike the Space Shuttle, VentureStar will be able to operate over populated areas and is intended to land at a speed of 165 knots - somewhat faster than the 130-knot average for commercial aircraft, but slower than 206 knots for the Shuttle.
Also, by using containerized payloads, VentureStar is expected to reduce the ground turnaround time between launches to seven days, although a requirement for as little as two days has been established. And, although engineers are designing the Lockheed Martin craft to operate unmanned, Rising says designers could build a manned variant later.
