Terran 1

Terran 1 consisted of two stages. The first stage was powered by nine Aeon 1 engines burning methane and oxygen propellants (methalox) in a gas-generator cycle, each producing 100 kN (23,000 lbf) of thrust. The second stage was powered by a single vacuum-optimized version of Aeon 1,[5] known as AeonVac, producing 126 kN (28,300 lbf) of thrust in vacuum.[6] Both stages were autogenously pressurized.[7]

The payload fairing measured 6.8 m (22 ft) long and had a diameter of 3 m (9.8 ft). Terran 1 was capable of up to 1,500 kg (3,300 lb) to low Earth orbit.[8] Relativity commonly stated a payload capacity of 1,250 kg (2,760 lb) to lower inclination low-Earth orbits and 900 kg (2,000 lb) to a Sun-synchronous orbit (SSO).[6][9]

The primary and secondary structures of Terran 1 were manufactured with Relativity's Stargate 3D printer out of aluminum alloy.[8] 90% of Terran 1 by mass consisted of printed components;[8] Relativity claimed that they could reduce the part count in the vehicle by 100 times compared to traditionally-manufactured rockets and manufacture an entire flight article from raw materials in 60 days.[8][10] Relativity's in-development Terran R launch vehicle will utilize the same tooling used to manufacture Terran 1.[5][11]

Relativity advertised a price per launch for Terran 1 of US$10 million in 2019.[12] The advertised price per launch had been increased to $12 million USD in 2021.[5]

Relativity received a Federal Aviation Administration (FAA) launch license to conduct the first launch of Terran 1, not-earlier-than (NET) 8 March 2023 from Cape Canaveral Space Force Station's Launch Complex 16.[14] Originally, another static fire was planned with the full rocket stack before first launch. Relativity believed it performed enough tests and instead attempted a launch.[7] Terran 1's initial flight scheduled for 8 March 2023 was scrubbed due to "exceeding launch commit criteria limits for propellant thermal conditions on stage two". A second launch attempt on 11 March was also scrubbed. Set for 18:00 UTC (14:00 EDT), high upper level winds prevented liftoff for over an hour. A second attempt at 19:35 UTC (15:35 EDT) was cancelled at T-70 seconds from a boat in the launch safety range. A third attempt at 19:42 UTC (15:42 EDT) was cancelled half a second before liftoff. The engines briefly lit up before shutting down from a "launch commit criteria violation". A final attempt occurred at 21:00 UTC (17:00 EDT). An issue with the automatic stage separation promptly closed the launch window.[15]

Another launch window for Terran 1's initial flight opened on March 23. After holding twice from a boat in the launch safety range, and high upper-level winds, the rocket lifted off at 03:25 UTC (23:25 EDT). Following a nominal liftoff and powered flight of the first stage, the second stage failed to ignite, leading to the loss of the mission. Preliminary investigations blamed the failure on a slower-than-expected valve opening as well as vapor ingestion into the liquid oxygen turbopump causing reduced performance.[16] Although the launch did not orbit, Relativity acknowledged the successful performance of the vehicle's 3D printed structures under flight loads.[17]

Following the loss of the first mission, the company abandoned further plans for Terran 1, instead choosing to focus efforts on developing the much larger reusable Terran R vehicle. Existing payloads on Terran 1 will likely have to be remanifested to Terran R or other flights.[4]

The following table was the list of planned launches prior to the vehicle's cancellation: