The STP-S29B mission is under the U.S. Space Force’s Space Systems Command, specifically the Small Launch and Targets Division. It’s part of the DoD Space Test Program (STP), which is intended to provide flight opportunities for scientific experiments and technology demonstrations to mature space-warfighting capabilities.

Astra Space, Inc., has been awarded the contract (task order) to provide launch services using its Rocket-4 vehicle. The contract is under the Orbital Services Program-4 (OSP-4) IDIQ vehicle.

The mission “manifest” is to be delivered to Low Earth Orbit (LEO). The payload is described in general terms as including experiments and technology demonstrations, possibly multiple payloads or “rideshare experiments.” The goal is to support R&D-type payloads for the DoD and to help mature technologies that support warfighter needs.

It is designated a Category 2 Mission Assurance mission, meaning more stringent requirements around reliability, testing, oversight, etc., than lower-category launches. Astra is required to work closely with government and independent mission assurance contractors to ensure proper performance.

The contract under which this launch was awarded has a fixed price of about US$11.45 million.

Courtesy of Astra and the United States Space Force.

Astra's Rocket 4 is an expendable, small-lift launch vehicle under development by the U.S.-based company Astra Space. Announced in May 2022, it is designed to deliver payloads of up to 600 kilograms to Low Earth Orbit (LEO) and is intended to replace the company's previous Rocket 3 series.

Rocket 4 is designed for a nominal payload capacity of approximately 600 kilograms to a circular 500 km altitude Sun-synchronous orbit (SSO). Initially, the vehicle will operate with de-rated engines to reduce performance and schedule risks, leading to an introductory payload capacity in 2024 of approximately 350 kilograms to a circular 500 km altitude SSO. As data from ground testing and early flights are gathered, the engine de-rating is expected to be reduced, increasing the payload capacity over time.

Specs

Height: 64 feet (19.5 meters)

Diameter: 72 inches (1.83 meters)

Stages: 2

Propellant: RP-1/LOX (kerosene/liquid oxygen)

First Stage Engines: Two turbopump-fed engines derived from Firefly's Reaver engine

Second Stage Engine: Single Hadley Vacuum engine from Ursa Major

First Stage Thrust: Approximately 70,000 lbf

Second Stage Thrust: Less than 2,000 lbf

Rocket 4 is under development following the cancellation of the Rocket 3 program due to reliability concerns. The first test flight is currently targeted for 2026. Astra has been awarded a launch task order for Rocket 4 through the United States Space Force’s Orbital Services Program (OSP)-4 contract, valued at $11.45 million, for a launch of an ESPA-class space vehicle and additional cubesats.

Astra has secured contracts for Rocket 4 launches, including the aforementioned task order with the U.S. Space Force. The company has also received funding from the Defense Innovation Unit (DIU) for the development and testing of Rocket 4.

Courtesy of Astra.

Space Launch Complex 46 (SLC-46) is a launch site located at Cape Canaveral Space Force Station in Florida. Originally built by the U.S. Navy in the mid-1980s for the Trident II missile program, the site saw its first launch on January 15, 1987. Between 1987 and 1989, a total of 19 Trident II test launches were conducted before the site was deactivated for military use.

In 1997, Space Florida took over operations of SLC-46 to support commercial launches. The first commercial launch from the pad occurred on January 6, 1998, when an Athena II rocket carried NASA’s Lunar Prospector mission to the Moon. Other notable early missions included the launch of Taiwan’s ROCSAT-1 satellite in 1999.

In recent years, SLC-46 has been used for a mix of government and commercial missions. These include launches of the Minotaur IV rocket carrying the U.S. Air Force’s ORS-5 satellite in 2017, NASA’s Orion Ascent Abort-2 test in 2019, multiple Astra Rocket 3 launches, and the U.S. Army and Navy’s Dark Eagle hypersonic missile tests in 2024 and 2025. Astra’s upcoming Rocket 4 will also launch from SLC-46, marking the first flight of this new vehicle from the pad.

The complex features a 7,000-square-foot support building, two 185-foot lightning protection towers, a Mobile Access Structure for various vehicle types, and a robust flame trench and underground equipment room. It supports launch vehicles up to 120 feet tall with payload diameters between 50 and 120 inches. Its adaptability and easternmost location at Cape Canaveral make SLC-46 a valuable site for both commercial and government space missions.

Photo courtesy of Astra / Brady Kenniston