Orbital Antares - Manual (Page 79)

Antares
®
OSP-3
User’s Guide
Section 8.0
– Non-Standard Services
Release 1.1 July 2013 68
Propyl Alcohol (IPA), HEPA filtered vacuums, etc.) to clean the fairing surfaces to meet the requirements.
When the fairing is not in use, it is covered with an appropriate cleanroom compatible material to maintain
cleanliness.
8.7. Secure FTS
The Secure FTS is achieved with the L-3 Cincinnati Electronics Model CRD-120/205 LV Command Re-
ceiver Decoder (CRD) that is compatible with the "High-Alphabet" range safety modulation format. The
receiver uses a prestored code unique to each specific vehicle to issue configuration and termination
commands. This provides an increased level of security over the standard FTS systems that use a basic
4 tone combination for receiver command and control. The CRD-120/205 LV Command Receiv-
er/Decoder was designed specifically to operate on the Delta expendable space launch vehicles for range
safety flight termination. This design incorporates redundancy in both hardware and software and High
Reliability piece-parts (in accordance with ELV-JC-002D) to ensure reliable, fail-safe operation.
Two vehicle modifications are made to incorporate Secure FTS on Antares. First, no Flight Termination
Logic Unit (FTLU) is needed since the secure CRD-120/205 performs the internal/external power switch-
ing and pro-vides the high current destruct ordnance output currently provided by the FTLU. This change
reduces the power required to be supplied by the FTS batteries, creating additional battery margin, and
simplifies the power and electrical harnessing. In
addition, the serial telemetry stream between the
FTLU and the encoder is replaced by analog
telemetry stream between the CR120A and the
encoder.
The vehicle-level Secure FTS subsystem is
tested in a similar fashion as the current FTS
systems. The CR120A is programmed with its
unique address and tested on vehicle using the
L3 ACE-613A Command Encoder. This test unit
is a computer controlled frequency synthesizer
that generates the High-Alphabet range safety
modulated UHF command signal required to
perform system level testing. A test tone se-
quence is generated that tests the combinations
of uplink tones to verify the receiver’s ability to
only respond to uplinks addressed to it, and that
the receiver responds properly issuing a destruct
command only when it is properly commanded
to do so within the required range of uplink sig-
nal levels. This testing also verifies the receiver’s
ability to provide accurate telemetry, allowing
proper system performance verification and sta-
tus monitoring of the entire Secure FTS system.
The Antares Secure FTS configuration is shown
in Figure 8.7-1. The Secure FTS subsystem is
powered by Orbital’s standard, qualified NiCd
Figure 8.7-1. Antares Secure FTS System Block
Diagram