# Falcon 9: Northrop Grumman finally launches its 21 satellites for the Pentagon's military "internet"

> The SDA-T1TL-A mission carries the first half of Northrop's share of the Transport Layer. The agency promised a launch a month; a year on, it is only on its fourth flight.

- Published: 4 Oct 2026 (2026-10-04)
- Author: Stanislav Milchev, Editor
- Section: Defence
- Tags: SDA, Tranche 1, Northrop Grumman, Falcon 9, Transport Layer
- Canonical URL: https://www.spacecapex.com/en/news/falcon-9-northrop-grumman-sda-tranche-1

On Monday at 1:17am Pacific time (11:17 in Bulgaria), **Falcon 9** is due to lift off from Vandenberg with 21 Northrop Grumman satellites for the US Space Force's Space Development Agency (SDA). The mission is called SDA-T1TL-A and is the fourth of nine Tranche 1 launches SpaceX will fly for the agency. If anything goes wrong, the backup window is on Tuesday at 1:08am local time.

The letter "A" in the name is a little misleading, because this mission should have flown long ago. The Transport Layer batch was conceived as 126 satellites, 42 each from Northrop Grumman, York Space Systems and Lockheed Martin. So far 63 of them are in orbit, carried on three flights: the first last September, the second in October and the third in July. York and Lockheed already have satellites up there. Northrop Grumman has only now delivered its first 21 to the base, and is launching half of its share.

This is where I find it hard not to be a little sceptical of the agency's promises. At the first launch in September 2025, the SDA said it would launch roughly once a month for nine months until the whole constellation was in orbit. A year later the Transport Layer is only on its fourth flight. The original contract of February 2022 called for the satellites to be ready for launch by September 2024; the first batch flew a year after that. An agency created precisely to move faster than the traditional Pentagon has, so far, rather traditional schedules.

![SDA](https://omlclbaklhdpibyhxubz.supabase.co/storage/v1/object/public/media/articles/1791108615176-lyjnl4.png)

So what is actually going up? A network the agency describes as global communications access and a persistent encrypted link for troops anywhere in the world. The satellites talk to each other via laser links, faster than radio, operate in Ka-band and will send data to the ground over the military **Link 16,** standard already used by NATO aircraft and ships. In other words, a fighter jet over the Middle East should be able to receive targeting data straight from orbit, without going through a ground station. The concept is impressive, although for Europe a network like this exists mainly in IRIS² presentations for now.

![SDA info](https://omlclbaklhdpibyhxubz.supabase.co/storage/v1/object/public/media/articles/1791108636929-dq6mea.png)

For those who follow the numbers: the first stage is flying for the sixth time, having previously launched NROL-179, **SDA-T1TL-E** and three **Starlink** missions, and will return to land at LZ-4 next to the launch site (a sonic boom at 1am is unlikely to delight the neighbours). The satellites are first released into a lower orbit, then raise themselves to their operational altitude of around 1,000 km. The full Tranche 1 batch will comprise 154 satellites, including 28 for missile tracking and four missile-defence demonstrators. Some of the tracking missions are assigned to ULA's Vulcan, which is currently grounded pending an investigation. If that drags on, Falcon 9 will probably have to pick up even more.

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Source: SpaceCAPEX — https://www.spacecapex.com/en/news/falcon-9-northrop-grumman-sda-tranche-1