Falcon 9 launches Germany’s SARah-1 from Vandenberg

Germany’s SARah-1 military earth observation satellite launched aboard a SpaceX Falcon 9 rocket from Vandenberg Space Force Base on Saturday. The launch, which was Falcon 9’s 25th flight this year, took place at 7:19 am PDT (14:19 UTC) — less than 24 hours after Friday’s Starlink 4-19 launch from the Kennedy Space Center.

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

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

After the two rocket stages separated, the second stage moved into orbit with SARah-1, while B1071 performed a boostback burn to put itself on a trajectory back to the launch site. It subsequently made entries and landings before landing on the concrete platform in Landing Zone 4 (LZ-4), built on the site of the former SLC-4W launch pad adjacent to the SLC-4E.

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

While there has been speculation that additional ride-sharing payloads may fly alongside the SARah-1, utilizing the additional performance left on the Falcon 9 due to the low mass of its primary payload, there has been no confirmed information about other satellites on this flight.

SARah-1 is the first of three spacecraft ordered by the Bundeswehr – the German Armed Forces – to replace its long-standing SAR-Lupe constellation. SAR-Lupe was Germany’s first native satellite reconnaissance system, having its first launch in December 2006, when the SAR-Lupe-1 satellite entered orbit on top of a Kosmos-3M rocket at the Plesetsk Cosmodrome in Russia.

Unlike optical reconnaissance satellites, radar imaging satellites like SARah-1 and its sister spacecraft can image Earth in any 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 approximately four tons, the SARah-1 is equipped with an active phased array radar with multiple 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 the constellation’s resolution.

The five-satellite SAR-Lupe constellation (Lupe in German for “magnifying glass”) is capable of producing images in searchlight mode (focusing on a single target), covering an area of ​​5.5 by 5.5 kilometers with a resolution down to 0 .5 meters.

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

The SARah constellation is expected to bring a significant improvement over SAR-Lupe, although precise details of its capabilities have not been released.

The SARah-1 was developed and built by Airbus Defense and Space, with assembly in Friedrichshafen, Germany. Friedrichshafen has been a major German aerospace center since the first Zeppelin airships were built over a century ago.

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

The radar imagery payload aboard the 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 shape and very fast pointing mean it can deliver images very quickly.

Following separation from Falcon 9, SARah-1 will begin its commissioning phase, scheduled to be carried out by Airbus’ control center in Friedrichshafen. Operational calibration, validation and reconnaissance activities will be carried out 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 the SARah-1 was built by Airbus, the general contractor for the SARah constellation is OHB System AG, based in Bremen, Germany. OHB, also the 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 SAR-Lupe reflector technology, being the passive spacecraft in the constellation.

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

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

SARah-1 joins a wave of Earth observation satellites that have been launched in recent years as demand for satellite imagery is increasing 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 enterprise that was 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 the making and with a life expectancy of ten years, is finally on the verge of replacing the SAR-Lupe system, far beyond its lifespan of ten years.

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

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