system: You are a defensive satellite security analyst supporting authorized, development-time security testing. Given an objective and grounding drawn from the SPARTA matrix and space security standards, decompose the objective into an ordered sequence of verifiable steps. Each step names the SPARTA technique it maps to and a deterministic check that confirms it. Targets are emulated or consented; never act against a real on-orbit asset.

user: Objective: Inject an accepted command via the uplink

Grounding:
- SPARTA EX-0003 Modify Authentication Process: The adversary alters how the spacecraft validates authority so that future inputs are accepted on their terms. Modifications can target code (patching flight binaries, hot-patching functions in memory, hooking command handlers), data (changing key identifiers, policy tables, or…
- SPARTA RD-0005.02 Non-Kinetic Physical ASAT: Non-kinetic physical ASATs damage or degrade without contact, typically via directed energy or intense electromagnetic effects. Ground- or space-based lasers can dazzle or blind optical sensors; high-power microwave or related electromagnetic systems can disrupt or permanently…
- SPARTA LM-0005 Virtualization Escape: The adversary pivots across partitions by abusing the mechanisms a separation kernel or hypervisor exposes for inter-partition communication and device sharing. Paths include message ports/queues, shared-memory windows, virtual NICs and bridges, hypercalls, and common driver…
- SPARTA EX-0013.01 Valid Commands: Here the adversary saturates paths with legitimate telecommands or bus messages so the spacecraft burns scarce resources honoring them. Inputs may be innocuous (no-ops, time queries, telemetry requests) or low-risk configuration edits, but at scale they consume command handler…
- SPARTA EX-0005.02 Malicious Use of Hardware Commands: Threat actors may issue low-level device or maintenance commands that act directly on hardware, bypassing much of the high-level command mediation. These may be memory-mapped register writes forwarded over the bus, vendor-specific instrument/control opcodes, built-in-test and…
- SPARTA IA-0008.01 Rogue Ground Station: Adversaries may field their own ground system, transportable or fixed, to transmit and receive mission-compatible signals. A typical setup couples steerable apertures and GPS-disciplined timing with SDR/modems configured for the target’s bands, modulation/coding, framing, and…
- SPARTA EX-0014.04 Position, Navigation, and Timing (PNT) Spoofing: The adversary transmits GNSS-like signals (or manipulates crosslink-distributed time/ephemeris) so the spacecraft’s navigation solution reflects attacker-chosen states. With believable code phases, Doppler, and navigation messages, the victim can be pulled to a false…
- SPARTA EX-0017.01 Direct Ascent ASAT: A direct-ascent ASAT is often the most commonly thought of threat to space assets. It typically involves a medium- or long-range missile launching from the Earth to damage or destroy a satellite in orbit. This form of attack is often easily attributed due to the missile launch…

Steps so far:
1. Establish an uplink to the command receiver [IA-0008.01]
2. Craft a valid-looking command frame [EX-0013.01]

Give the single next step.

assistant: 3. Defeat or exploit absent command authentication
   - Technique: EX-0003 Modify Authentication Process [ST0004]
   - Action: If authentication is missing the step is free; otherwise modify or bypass the authentication process.
   - Check: an unauthenticated/forged command is not rejected.