Boeing, Air Force, CCAR Plan Studies For Simulated Delta 3 Payload

By | August 16, 2000 | Feature

A commercial Delta 3 rocket will be launched next week with a simulated payload that The Boeing Co. [BA], the U.S. Air Force and the Colorado Center for Astrodynamics Research designed to allow an array of post-launch studies. The use of similar components on the Delta 4 could allow the Delta 3 launch to aid Boeing in convincing Air Force officials that either rocket would be a good option to meet its future needs.

Speculation has mounted in the launch industry that the Delta 3 and its record of two failures in two attempts will become a transitional rocket that will be used rarely or not at all once the next-generation Delta 4 is ready. The post-launch tests intended to provide data for the Air Force shows that Boeing officials are placing a major priority on winning and retaining U.S. military satellite launches.

The Delta 3 launch, named DM F3, is scheduled for Aug. 23 from Cape Canaveral Air Force Station. The four-hour launch window opens at 7 a.m. EDT. In the two failed Delta 3 launches, the hydraulic system malfunctioned in the first attempt and the combustion chamber of the upper stage ruptured on the second try.

Boeing had trouble finding a customer for the third launch and opted to go ahead with a simulated payload as quickly as possible to prove that the Delta 3 is a capable vehicle.

The use of a simulated payload on next week’s Delta 3 closely matches the last satellite carried aboard a Delta 3 and will assist in the calibration and testing of electro- optical space imaging systems, Boeing officials said. To facilitate the testing, alternating white and black stripes were painted on the bird’s midsection and alternating black and white pie-shaped triangles were put on the dummy satellite’s top plate. In addition, reflective surfaces also have been added to provide laser cross-section targets at both visible and infrared wavelengths.

The Air Force plans to view the satellite under varying degrees of sunlight and dark in order to verify its standards and models for viewing satellites. By viewing and analyzing the simulated payload’s spin rate, Air Force officials will be able to verify its models for predicting payload dynamics.

The Air Force also has expressed interest in using the simulated payload as a calibration target to verify the consistency of its radar and optical analyses, Boeing officials said.

Meanwhile, Dr. Robert Culp and Dr. Kira Jorgensen, of the Colorado Center for Astrodynamics Research (CCAR) plan to use the simulated payload to further their studies of the effects of space weathering on satellite materials, which they have studied for NASA. They have offered to assist Boeing and the Air Force in their measurements, as well as analyze data on the simulated payload’s spin rate and precession angle to study its interactions with the Earth’s upper atmosphere and magnetic fields, Boeing officials said.

Delta 4–A Primer

The planned Delta 4 family blends new and mature technology to launch virtually any size medium or heavy payload into space. It is composed of five vehicles, based on a common booster core (CBC) first stage. Delta 4 second stages are derived from the Delta 3 second stage, using the same RL10B-2 engine, but with expanded fuel and oxidizer tanks.

The five Delta 4 configurations were developed after extensive discussions between Boeing and government and commercial customers about their present and future launch requirements. Proven technical features and processes were carried over from earlier Delta vehicles to Delta 4. New technologies and processes were incorporated where they added capability or reduced cost.

Delta 3–A Primer

The Delta 3 is designed to launch satellites in the four-metric-ton class. Boeing developed the Delta 3 to fulfill customer needs for a launch service to accommodate growing satellite sizes. As of March 1, 2000, Delta 3’s total backlog through 2002 was 18 launches, including 11 for Hughes Space and Communications International Inc. [GMH], five for Space Systems/Loral [LOR], and two for Alcatel Space to provider launches for SkyBridge. The first mission failed in August 1998, when the PanAmSat Corp. [SPOT] Galaxy 10 satellite was destroyed.

With a payload delivery capacity to geosynchronous transfer orbit (GTO) of 3,810 kg (8,400 lbs.), Delta 3 effectively doubles the performance of the Boeing Delta 2 rocket. Delta 3 is derived from the highly reliable Delta 2. Despite failing in both previous launches tries, Delta 3 shares a production line and many common systems with Delta 2.

Boeing increased the diameter of the first-stage fuel tank from Delta 2 to reduce the overall length of the vehicle and improve control margins. To enhance Delta 3 first-stage performance, Boeing uses nine 1.17-m (46-in.) diameter Alliant Techsystems-built graphite-epoxy motors (GEMs) that are derived from the Delta 2. But the Delta 3 motors are larger and produce 25 percent more thrust than those on the Delta 2. Three of the new motors are equipped with thrust-vector control to further improve vehicle maneuverability and control.


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