Scenario 24 - North Atlantic Storm

Shift Turnover Notes

Date: Tuesday 27 April, 0300 UTC Network: GW-01 Galway and SH-02 Shetland - NATS Europe Incident Commander: You SH-02: Fiona MacLeod Constellation Ops: Anneke Visser, Rotterdam Site Lead: Charlie Brooks (on the phone) Group Security: Priya Sharma, NATS Group CSIRT

Met Éireann orange warning: heavy rain 02:30-03:30, sleet from 03:30, west coast. Three P1 contacts in the hour, unassigned. HOP-SAR3-01 staged at both ends since Sunday. Galway TX on 1,405, RX on 1,414, BUC muted; Shetland RX on 1,414. Both references locked. Nothing on either board.

• Night shift (turnover log, 0250)

Charlie (text, 0240):

“Orange warning on the coast, three birds in an hour, and you are incident commander for the network tonight - Fiona is on SH-02, Anneke is on the constellation, I am on the phone. Plan first. Everything they have done to us in two weeks, assume they do again, all at once, in the sleet. Everything you have done, you can do again too.”

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Tonight’s Passes (epoch 03:00:00 UTC, 0° horizon)

Satellite	Site	AOS	Rise az	Max el	Culmination	LOS	Work
MERIDIAN-SAR-1	GW-01	03:19:58	005°	30.2°	03:24:44 (714 km)	03:29:28	NMW collect, video 1,414 MHz IF
MERIDIAN-SAR-2	SH-02	03:31:01	139°	35.1°	03:35:59 (688 km)	03:41:01	NMW collect, video 1,370 MHz IF - post-burn set
MERIDIAN-SAR-3	GW-01	03:52:00	023°	28.4°	03:56:49 (754 km)	04:01:35	Commanding, window 03:52:21-04:01:15; PLD-SAFE

Frequency Plan (MER-IF-2027-04b)

Signal	RF	IF	LO
SAR-3 TT&C uplink	14,065 MHz	1,465 MHz (TX)	BUC 12,600 low-side: IF = RF − LO
SAR-3 video	11,760 MHz	1,340 MHz (RX)	LNB 13,100 high-side: IF = LO − RF
SAR-3 beacon	11,785 MHz	1,315 MHz
Hop set HOP-SAR3-01	14,061 / 14,063 / 14,065 / 14,067 / 14,069 MHz

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The Hour

Time	Where	What	The answer
03:01-03:16	GW-01	Rain band, 30 mm/h	Nothing. It ends before SAR-1 rises
03:15	SAR-2	Conjunction-avoidance burn; station set stale	Load the post-burn set before Shetland’s AOS
03:21:30-03:28:30	GW-01	Terrestrial carrier 1,410 MHz IF in SAR-1’s band, 60 s on / 30 s off	Notch 1410 / 2 MHz / 30 dB; keep the collect
03:25 →	SH-02	GNSS spoof on Shetland’s reference; Galway reads zero	Shetland to holdover; Galway stays on GNSS
03:40-04:10	GW-01	Sleet	Feed heater on before 03:40
03:55-04:01:40	SAR-3	Jammer on the 14,065 MHz command carrier	Call the denial; hop; PLD-SAFE through it

Every one of those has a procedure from an earlier shift. The capstone is whether they hold together, in order, with the storm on top.

Caution

The plan first. Three P1 contacts, two sites: SAR-1 and SAR-3 can only be flown from Galway tonight; SAR-2 goes to Shetland, where it peaks at 35° in clear air while Galway has sleet between its two windows. Nothing about the adversary is in the plan - the plan is geometry and weather, and it is right before anything else happens.

Two Sites, One Network

The spoof is on Shetland this time. On the 19th Galway walked and Shetland was the cross-check; tonight it is the other way round. The signature is identical - ΔT walking, constellation healthy, the other site reading zero - and so is the answer: holdover at the site being lied to, GNSS kept at the site that is honest. Fiona’s SAR-2 collect flies on the oscillator; the frozen offset goes in the log.

The Command Contact

SAR-3 rises into sleet on a heated feed. Centre the analyzer on the 1,315 MHz beacon with a 2 MHz span and confirm it on RX analysis. Chain up at 03:52:21, HK-DUMP on the fixed carrier, then PLD-SAFE - which comes back Uplink denied - carrier jammed at 03:55.

Suspect	Why it is not
Rain fade on the uplink	HK-DUMP ACKed in the same sleet on the same power two minutes earlier; Ku uplink fade at 28° in sleet is a decibel or two, and the NAK says “jammed”, not “weak”
The key	Valid at both ends; a key rejection is its own reason on the console
Shetland’s holdover	A different site, a different reference, a receive-only pass

Same call as the 16th and the 24th: Anneke keys SAR-3, Load Hop-Set Key, Frequency hopping, SYNC LOCKED, resend. The point of the capstone is that it is the same call.

Note

Write the incident log as you go. Half the hour is logged before the half that matters most, because the commander who writes as they go is the one who can hand over.

Incident Log IL-2027-0427-NATS-EU

Section	Line
Incident Log	First half hour: rain, burn, SAR-1 under the carrier, spoof on Shetland, SAR-2 on the oscillator. Second: heater, SAR-3, the NAK, the hop, PLD-SAFE, safed
Handover	What is still true at 04:15, what is staged for it, and that no procedure changed - because every event had one and they held together

Three contacts delivered. That is the sentence the board reads, and it is the end of the arc.