SDA Transport Layer satellites by York Space Systems: status and timeline

SDA Transport Layer satellites

Give US forces a fast, hard-to-destroy data network in space by launching many cheap, mass-produced relay satellites in planes, replaced every few years in new tranches.

DeployStage 4 of 5

42 Tranche 1 satellites in orbit; 62 Tranche 2 Alpha and 10 Gamma on order, launching from 2027.

Updated 16 Jul 2026Checked 11 Oct0 updates this week

Milestones

Next · First Tranche 2 Alpha plane launches

Selected as one of three Tranche 1 Transport Layer buildersFeb 2022Complete.
10 Tranche 0 transport satellites launched2023Complete.
62-satellite Tranche 2 Alpha award ($615M)20 Oct 2023Complete.
First 21 Tranche 1 satellites launched10 Sep 2025Complete.
Second 21 Tranche 1 satellites launched; 42 in orbit16 Jul 2026Complete.
First Tranche 2 Alpha plane launchesTarget 2027+12 mo~~originally 2026~~Not yet reached.

Most important updates

Upcoming

Q4 2026Spacecraft delivery for York's Nemesis mission (next)
2027First Tranche 2 Alpha plane launches+12 mo~~originally 2026~~

Current obstacles

Early technical problemsSoftware and hardware issues on the first Tranche 1 batch slowed checkout and paused launches; the second batch went much faster.
Tranche 2 timingTranche 2 launches were once slated to begin in 2026; the agency now plans to start them after finishing Tranche 1, which it targets for spring 2027.

Physics limits

Low orbit needs many satellitesA satellite a few hundred kilometres up sees only a small patch of Earth and passes overhead in minutes, so continuous coverage takes hundreds of satellites.
Laser links must aim preciselyLaser beams between fast-moving satellites thousands of kilometres apart must be pointed within tiny angles, which demands very stable pointing hardware.
Drag and radiation shorten lifeThin upper air slowly drags low satellites down and radiation wears electronics, so satellites need replacing after several years.

How it works

4 parts

Bus

A standard spacecraft body

Each satellite uses a mass-produced York bus that supplies power, pointing and propulsion; the military payload rides on top.

Mesh

Satellites relay to each other

Laser links pass data from satellite to satellite, so a signal can cross the globe in orbit without waiting for a ground station.

Planes

Launched 21 at a time

A Falcon 9 drops a full orbital plane of 21 satellites; several planes together give near-constant coverage of a region.

Tranches

Refreshed every few years

New tranches with better hardware replace older ones, so the network improves on a schedule instead of waiting decades.

Spec sheet

Spec	SDA Transport Layer satellites
Tranche 1 satellites in orbit	42^R (reported)
Tranche 2 Alpha satellites ordered	62^R (reported)
S-CLASS payload mass	85+ kg^R (reported)
S-CLASS peak power	500 W (extensible to 1 kW)^R (reported)
LX-CLASS payload mass	300+ kg^R (reported)
M-CLASS payload mass	1,000+ kg^R (reported)
Denver production capability (2022)	750+ satellites/year^R (reported)

^R reported by the company

Update log

2 updates

Thu 16 Jul

Major: Falcon 9 launches 21 more York satellites for SDA Tranche 1, giving York 42 in orbitPressTest

Fri 20 Oct 2023

Major: Space Development Agency orders 62 Tranche 2 transport satellites from York for $615MPressCommercial

About York Space Systems

The team behind SDA Transport Layer satellites

York Space Systems

Mass-produced satellite buses, SDA Transport Layer

York Space Systems is a Denver satellite maker that builds standard spacecraft platforms on a production line, mainly for the US military. It is the lead builder of data-relay satellites for the Space Development Agency's low-orbit network.

42 York-built Tranche 1 transport satellites are in orbit after launches in Sep 2025 and Jul 2026.
Listed on the NYSE in Jan 2026, raising $629M at about a $4.75B market value.
Cut 2026 revenue guidance to $375-405M in August as Pentagon buying shifted to slower contracts.

yorkspacesystems.com (opens yorkspacesystems.com)Company profile →

Founded: 201214 yrs
Headquarters: United States
Status: Public
Listed: YSS (opens google.com)NYSE
Valuation: $4.8Bmarket capJan 2026
Last round: IPO (NYSE: YSS) · $629M29 Jan 2026
Works in: SpaceflightSatellites
Coverage: 1 program · 4 updateslatest 13 Aug 2026checked 11 Oct
Lead investors: AE Industrial Partners
Customers: Space Development Agency (opens defensenews.com)
Investors: AE Industrial Partners (opens satellitetoday.com)
Suppliers: SpaceX (opens spaceflightnow.com)
People: Dirk WallingerFounder & CEO

Spec

SDA Transport Layer satellites

Tranche 1 satellites in orbit

42^R (reported)

Tranche 2 Alpha satellites ordered

62^R (reported)

S-CLASS payload mass

85+ kg^R (reported)

S-CLASS peak power

500 W (extensible to 1 kW)^R (reported)

LX-CLASS payload mass

300+ kg^R (reported)

M-CLASS payload mass

1,000+ kg^R (reported)

Denver production capability (2022)

750+ satellites/year^R (reported)