The countdown to Relativity Space’s first launch was halted about a minute before liftoff Wednesday at Cape Canaveral when sensors detected hotter-than-expected liquid oxygen on the Terran 1 rocket’s second stage, delaying until on Saturday the first test flight of the 3D printed launcher.
The 110-foot-tall (33.5-meter) Terran 1 rocket had a three-hour launch window on Wednesday, and the Relativity launch team counted down to a target liftoff time of 2:40 p.m. EST (1940 GMT) . But a computer overseeing the final pre-flight checks ordered an automatic shutdown 1 minute and 10 seconds before launch.
The countdown stopped to give engineers time to assess data indicating that the liquid oxygen on Terran 1’s upper stage was not at the correct temperature. Relativity’s launch team, working in a control room at Cape Canaveral, first reset the countdown for another launch run before the end of Wednesday’s window.
But Clay Walker, Relativity’s launch director, canceled the countdown: “All parties, we’re scouring for the day. Thanks for playing.”
The aerospace start-up plans to try again on Saturday. The Terran 1 rocket from Launch Complex 16 was drained of methane and liquid oxygen propellants as ground crews prepared for another launch attempt during a three-hour window on Saturday opening at 1 p.m. EST (1800 GMT).
California-based Relativity Space said the launch team canceled the launch attempt on Wednesday “due to exceeding the launch engagement criteria limits for the thermal conditions of the propellant in Stage 2.”
“When you use liquid natural gas, the methane needs time to reach the right concentration,” Relativity tweeted. “That’s why our next attempt will be in a few days.”
A SpaceX Falcon 9 rocket is scheduled to lift off Thursday afternoon from a launch pad a few miles north of Relativity’s platform along with a batch of 40 OneWeb internet satellites. The Falcon 9 first stage will return to the SpaceX landing zone near the Relativity launch site at Cape Canaveral Space Force Station.
There’s a 90% chance of good weather for Relativity’s next launch attempt on Saturday.
“A strong cold front is expected to move across the Florida Peninsula from Friday evening through early Saturday morning,” forecasters from the Space Force’s 45th Weather Squadron wrote Wednesday. “The humidity ahead of the front will remain rather limited, so we shouldn’t see widespread precipitation, although scattered showers and isolated thunderstorms are possible.
“After the frontal crossing, expect brisk northerly winds with sustained readings of 10-15 mph gusting to around 20 mph. There may be a few lingering clouds early in the day (Saturday), but they will give way to clear skies throughout the count. A few cumulus clouds may persist, so the main concern will be the cumulus rule.
Relativity Space dubbed the Terran 1 test flight “Good luck, have fun.” It will not carry any customer satellites, but will attempt to fly into a 124-mile (200-kilometer) orbit about eight minutes after liftoff from Cape Canaveral.
The Terran 1 rocket could become the first methane-fueled launch vehicle to reach orbit if the eight-minute flight goes well on Wednesday, beating two much larger rockets – ULA’s Vulcan and SpaceX’s Starship – which are set to attempt their first flights large-scale testing in the future. weeks or months.
Tim Ellis, co-founder and CEO of Relativity Space, said methane is the “propellant choice of the future, especially for reusable rockets”.
Methane is a more efficient fuel than kerosene, which is used on SpaceX’s Falcon 9 rocket, Russia’s Soyuz launch vehicle and ULA’s Atlas 5. It also burns cleaner and leaves less residue inside an engine than kerosene, making it easier to refurbish and reuse between missions.
Even before the first Terran 1 left the launch pad, Relativity began development of a larger, fully reusable rocket called Terran R, a vehicle the company says will become a “point-to-point space freighter capable of carry out missions between the Earth, the moon and Mars.
The Terran 1 is also the first orbital-class rocket to be made primarily with 3D printing.
“Forward, and proud of the team today for a professional and smooth first operation!” Ellis tweeted after Wednesday’s launch delay.
Email the author.
Follow Stephen Clark on Twitter: @StephenClark1.