Falcon 9 launches German SARah-1 from Vandenberg

Germany’s SARah-1 military radar Earth observation satellite was launched on a SpaceX Falcon 9 rocket from Vandenberg Space Force Base on Saturday. The launch, which was the Falcon 9’s 25th flight this year, took place at 7:19 a.m. PDT (2:19 p.m. UTC) — less than 24 hours after Starlink 4-19 launched Friday from Kennedy Space Center.

Saturday’s launch used the flight-proven Falcon 9 1071-3 booster. This booster previously flew missions NROL-87 and NROL-85 from Vandenberg earlier in 2022, and the SARah-1 mission marks its third flight. SpaceX won the SARah launch contract for the German government in 2013.

Lifting off from Space Launch Complex 4E (SLC-4E) at Vandenberg Space Force Base, Falcon 9 headed south targeting a sun-synchronous polar orbit – a type of orbit commonly used by Earth observation satellites .

After the two stages of the rocket separated, the second stage went into orbit with SARah-1, while B1071 performed a booster burn to place itself on a return trajectory to the launch site. It then performed entry and landing burns before landing on the concrete slab at Landing Zone 4 (LZ-4), built on the site of the adjacent former SLC-4W launch pad. to SLC-4E.

As the B1071-3 returned to the launch site, the Falcon 9 second stage and its single Merlin Vacuum (MVac) engine placed the SARah-1 satellite into orbit. SARah-1 will operate in a circular orbit inclined at 98.4 degrees to the equator, at an altitude of approximately 750 kilometers above the Earth’s surface.

Although there has been speculation that additional carpool payloads could fly with SARah-1, using the extra performance remaining in the Falcon 9 due to the low mass of its main payload, there is no had no confirmed information regarding other satellites on this flight.

SARah-1 is the first of three spacecraft ordered by the Bundeswehr – the German armed forces – to replace their long-running SAR-Lupe constellation. SAR-Lupe was Germany’s first indigenous satellite reconnaissance system, having seen its first launch in December 2006 when the SAR-Lupe-1 satellite was lifted into orbit atop a Kosmos-3M rocket from the Russian cosmodrome from Plesetsk.

Unlike optical reconnaissance satellites, radar imaging satellites like SARah-1 and its sister spacecraft can image the Earth in all weather and lighting conditions, such as a cloudy, rainy night, or other conditions that would limit optical observation, using a technique called synthetic aperture radar. (SAR).

With a mass of about four tons, SARah-1 is equipped with an active phased array radar with several antenna elements that can be electronically steered. Later this year, SARah-1 will be joined by the SARah-2 and SARah-3 spacecraft, which carry passive reflector antennas. Passive satellites will work with SARah-1 to increase constellation resolution.

The constellation of five SAR-Lupe satellites (Lupe being German for “magnifying glass”) is capable of producing images in projector mode (single target focus), covering an area of ​​5.5 by 5.5 kilometers with a resolution up to 0.5 meters.

Each of the 770 kilogram SAR-Lupe satellites is also capable of mapping an area up to 60 kilometers by 8 kilometers at a resolution of one meter and image at least 30 areas of interest per day. The constellation has a response time to requests to image a given area of ​​ten hours or less.

The SARah Constellation is expected to be a significant improvement over SAR-Lupe, although specific details of its capabilities have not been disclosed.

SARah-1 was developed and built by Airbus Defense and Space, with assembly taking place in Friedrichshafen, Germany. Friedrichshafen has been an important center for German aerospace since the first Zeppelin airships were built there more than a century ago.

Rendering of SARah-1 in orbit (credit: Airbus)

The radar imagery payload onboard SARah-1 is a further development of a system previously flown on the already-in-orbit TerraSAR-X, TanDEM-X and PAZ satellites, which were also built by Airbus. Its flexible formatting and very fast pointing means it can deliver images very quickly.

After separating from Falcon 9, SARah-1 will begin its commissioning phase, scheduled by the Airbus control center in Friedrichshafen. Operational calibration, validation and reconnaissance activities will be handled by the Bundeswehr’s own Satellite Control Center. Ground stations in Gelsdorf, Germany, and Kiruna, Sweden, will be used to communicate with the spacecraft.

While SARah-1 was built by Airbus, the general contractor for the SARah constellation is OHB System AG, headquartered in Bremen, Germany. OHB, also prime contractor for the existing SAR-Lupe system, is responsible for building the sister spacecraft SARah-2 and SARah-3. SARah-2 and 3 will use reflector technology from SAR-Lupe, being the constellation’s passive spacecraft.

The three SARah satellites are expected to fly aboard SpaceX Falcon 9, SARah-2 and 3 rockets to be launched together later this year.

The SARah constellation, with the SARah-1 center (credit: OHB)

SARah-1 joins a wave of Earth observation satellites that have been launched in recent years as demand for satellite imagery increases due to wars, natural disasters, climate change and other events. Germany and other regional powers around the world are increasingly deploying independent satellite reconnaissance systems, an endeavor dominated by the United States and the Soviet Union during the Cold War.

As Europe faces new security threats, the Bundeswehr’s SARah system, nine years in development and with an expected lifespan of ten years, is finally set to replace the SAR-Lupe system, well beyond its own expected ten-year lifespan.

(Main image: Falcon 9 lands at LZ-4 after launching SARah-1. Credit: Michael Baylor for NSF)

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