Northrop Grumman is preparing for its first flight of a Minotaur rocket from California in nearly 14 years. The four-stage Minotaur 4 rocket will launch the NROL-174 mission for the National Reconnaissance Office.
Liftoff from Space Launch Complex 8 (SLC-8) is targeted for 12:33 p.m. PDT (3:33 p.m. EDT, 1933 UTC). The NRO gave no indication prior to launch that it would facilitate a livestream of the mission’s countdown or liftoff.
As is typical with NRO missions, little is known about what is being sent into orbit. In a prelaunch press kit, the intelligence-gathering agency said the NROL-174 consists of “multiple national security payloads designed, built, and operated by the NRO.”
The first three stage of the Minotaur 4 rocket consist of solid rocket motors from decommissioned Peacekeeper intercontinental ballistic missiles (ICBMs) and the fourth stage is a commercial, solid rocket upper stage. The rocket is capable of launching up to 1,730 kg (3,814 lbs) of payload mass to low Earth orbit.
The first Minotaur 4 rocket launched on April 22, 2010, from SLC-8, and there have been three Minotaur 4 rockets launched from there, most recently NROL-66 on Feb. 6, 2011, back when the rocket was managed by Orbital Science Corporation.
That company merged with the defense and aerospace sectors of Alliant Techsystems to become Orbital ATK on April 29, 2014. Northrop Grumman announced its intention to acquire Orbital ATK for $9.2 billion in September 2017, with the deal being approved by the Federal Trade Commission in December 2018.
The Minotaur 4 rocket was procured for the NROL-174 mission under the Rocket Systems Launch Program (RSLP). That program is under the Orbital/Suborbital Program-3 contract, which is managed by the U.S. Space Force’s Space Systems Command (SSC).
“RSLP is the small launch counterpart to SSC’s National Security Space Launch program and focuses on the small launch market,” the NRO wrote in a prelaunch press kit. “RSLP primarily launches more risk-tolerant experimental, research and development, responsive space and operational missions.”
The OSP-3 contract finished awarding missions in November 2019, which was a month after the OSP-4 contract was established.
The OSP-3 contract established an indefinite delivery, indefinite quantity for launch capability with a cap of $900 million. Launch are dolled out using firm-fixed price contracts for each mission.
Spaceflight Now reached out to SSC to ask how many missions remain within the OSP-3 contract that have not yet launched. This story will be updated when we hear back.
Around the country and back again
One of the unique aspects to the Minotaur rocket program is that the vehicle is agnostic to location.
After making its suborbital debut in a Minotaur 4 Lite configuration on April 22, 2010, Orbital Science Corporation launched a Minotaur 4 from SLC-8 at Vandenberg that September.
That was followed by the Department of Defense’s Space Test Program’s S26 (STP-S-26) mission at the Kodiak Launch Complex on Nov. 19, 2010. It used a Minotaur 4 rocket.
Another suborbital flight followed at SLC-8 using a Minotaur 4 Lite on Aug. 11, 2011, and then the TacSat-4 mission featured the debut of the Minotaur 4+ configuration when it launched from Kodiak on Sep. 27, 2011.
Nearly six years went by before the next Minotaur 4 launch on Aug. 26, 2017. That was the first launch of the rocket from what was then Cape Canaveral Air Force Station and its pad, Space Launch Complex 46 (most recently used by Astra Space’s Rocket 3).
The last time a Minotaur 4 rocket took flight was up at Mid-Atlantic Regional Spaceport at the southern tip of NASA’s Wallops Flight Facility in Virginia. That mission, NROL-129, launched on July 15, 2020.
There are at least two more launches of Minotaur rockets on the books following the NROL-174 mission. The vehicle was tasked with the launches of STP-29A, which was originally scheduled to fly in September 2024, and USSF-261S-A, which had a target launch date of May 2025.
Spaceflight Now has asked SSC what the timeline for those missions looks like and is waiting to hear back.
