After Dramatic Engine Start and Recycle, Relativity Space Scrubs First Terran-1 Launch

After Dramatic Engine Start and Recycle, Relativity Space Scrubs First Terran-1 Launch

An eerie blue exhaust glowed beneath nine Aeon-1 engine bells during Saturday’s launch attempt. Image Credit: Relativity Space

After a disappointing scrub on Wednesday, due to a vexing issue pertaining to the thermal conditioning of its propellant load of Liquid Natural Gas (LNG) and Liquid Oxygen (LOX), Relativity Space suffered further misfortune on Saturday, when a frantic effort to retrieve its first Terran-1 booster from Launch Complex (LC)-16 at Cape Canaveral Space Force Station, Fla., was aborted seconds before. at the liftoff. The teams will now await a third chance to fly a mission whose cheerfully named “Good Luck, Have Fun” produced little luck and little fun, though certainly provided more than its fair share of fun and drama.

The initial Terran-1 launch attempt on Wednesday was scrubbed. Video Credit: Relativity Space/YouTube

Relativity Space, founded in 2015 by aerospace engineers Tim Ellis and Jordan Noone—formerly of Blue Origin and SpaceX, respectively—is based in Long Beach, Calif., and aims to build a fleet of launch vehicles orbital class, produced almost entirely through additive manufacturing. With its in-house-designed Stargate system, about 85 percent of the total mass of the first-generation Terran-1 rocket was 3D-printed, as Relativity aims to build entire boosters, priced as little of $12 million, in under 60 days .

Although the first Terran-1 mission carried no payload, it carried a 3D-printed piece from the Stargate printer, measuring 6.5 inches (16.5 centimeters) across and weighing in the region of 3 pounds (1.4 kilograms ). But as outlined in the Terran-1 story before the launch of AmericaSpacewon the rocket’s capacity to lift 2,750 pounds (1,250 kilograms) to a low-Earth orbit of 115 miles (185 kilometers) and up to 1,500 pounds (700 kilograms) to a Sun-synchronous orbit of 750 miles (1,200 kilometers) it is an emerging commercial client, from telesat in Momentum and from Iridium in Spaceflight, Inc.

Despite highly favorable weather on Wednesday, the Terran-1 launch was scrubbed due to a propellant conditioning issue in the second stage of the booster. Photo Credit: Trevor Mahlmann/Relativity Space/Twitter

After the Terran-1 flight hardware arrived at the Cape in June, it underwent an intensive regime of spin-start tests of its nine Aeon-1 first-stage engines, licensed by the Federal Aviation Administration (FAA) to first covering July to December for its inaugural launch attempt. But the need for further hot-fire tests, Eastern Range issues and last September was the attack of Hurricane Ian pushed the mission deep into the fall and eventually into the spring of 2023.

Last Wednesday, despite perfect weather conditions along the Space Coast, the first launch attempt was scrubbed when there was an issue with the thermal conditioning of the rocket’s Liquid Natural Gas (LNG) and Liquid Oxygen (LOX) load. . After several delays, the engineers successfully pressed on to Terminal Count, establishing the Terran-1 propellant tanks at flight pressures, preparing the nine Aeon-1 engines for ignition and “strongback” Transporter-Erector (TE) recovery is initiated.

Terran-1 is 85-percent 3D-printed by mass, according to Relativity Space. Image Credit: Relativity Space

But Wednesday is not Relativity day. Sadly, in T-70 seconds, just as the rocket’s on-board computer prepared to carry out the main command of all the vehicle’s critical functions, an autonomous abort was called. Efforts continued to achieve a launch as the final minutes of the launch window waned, but it never happened.

“Today’s launch attempt…was scrubbed due to exceeding Launch Commit Criteria (LCC) limits for propellant thermal conditions in Stage 2,” Relativity explained minutes after the scrub, with updates blaming a malfunctioning Ground Support Equipment (GSE) valve . “Additional mitigations” were reportedly put in place to ensure that Terran-1’s oxidizer load was maintained within its required temperature range. It was then determined that the next available opportunity to launch was during a three-hour window from 1 pm to 4 pm EST Saturday.

Terran-1 is the first step in Relativity’s effort to build a fleet of 3D-printed orbital-class rockets. Image Credit: Relativity Space

Weather conditions for the weekend are predicted to be extremely favorable, promising a 90-percent “Go” for the Saturday window and reaching up to 95 percent on Sunday. “The potential for showers will continue into the evening,” the 45th Weather Squadron at Patrick Space Force Base said in its L-1 forecast Friday, “but the threat for thunderstorms should end in the hours in the early evening.”

A strong cold front, which is expected to move into Central Florida beginning late Friday, is expected to cause cloudiness to clear from the region by the launch of Saturday’s window. “Some low clouds will likely be around at the start of the count,” added the 45th, “but should clear the area quickly.”

The nine Aeon-1 engines were gimbaled in a final control test before launch. Image Credit: Relativity Space

Overall, this highly positive meteorological picture risks only a slight chance of violating the Cumulus Cloud Rule, in case some stray clouds remain in place. Scattered cumulus clouds are expected between 3,500 feet (1,000 meters) and 7,500 feet (2,200 meters), with temperatures hovering around 23-26 degrees Celsius (75-80 degrees Fahrenheit) and visibility of about 7 miles (11.2 kilometers).

Relativity heading into Saturday will be bullish optimism. “Pad is cleared,” it tweeted shortly after 9 am EST, sharing a beautiful sunrise behind their 3D-printed bird.

At T-6 seconds, the nine Aeon-1 engines ignited, producing about 207,000 pounds (95,000 kilograms) of thrust. Image Credit: Relativity Space

But, as he has often proven, Mother Nature is a tough housewife to work with. “We are Go for prop load, which is getting underway,” Relativity tweeted at 10:30 am EST, as LNG and LOX began flowing into the 110-foot-tall (33.5-meter) rocket’s tanks, “but higher- Air levels are a potential concern today and we continue to monitor.”

As propellant loading was completed, Relativity targeted a new T-0 at 1:45 pm EST, less than an hour into the window. “Range is Green, vehicle is healthy,” it tweeted. “We continue to monitor upper level air conditions.”

The roar of Aeon-1’s nine engines rose, then fell silent, as Terran-1’s second launch attempt was aborted. Image Credit: Relativity Space

However, as the clocks ticked down to T-20 minutes, the teams opted to stop the countdown, due to “marginal” upper-level winds. A revised T-0 of 2:35 pm EST was established, just past the halfway point of Saturday’s window.

Launch Director Clay Walker polled his team at 2:20 pm EST, receiving a compelling string of “Go” calls on the net. Heading deep into Terminal Count, the TE was withdrawn on command from Terran-1 at T-3 minutes, while the rocket switched to internal power and headed for Terminal Count at T-70 seconds.

An ominous plume of smoke hung around LC-16 in the moments after Saturday’s scrub at T-0.5 seconds. Image Credit: Relativity Space

However, the gremlins weren’t done with the snakebite mission. The clocks stopped again at T-70 seconds, when a call “Hold, Hold, Hold” was issued in response to a boat straying within the launch danger zone.

By the time the offending vessel was driven off, the countdown continued, counting down to a liftoff at 2:46 pm EST. At T-6 seconds, the nine Aeon-1 engines at the base of Terran-1’s first stage roared to life, igniting in fury with an ominous blue-tinted exhaust and raging propulsive yield that 207,000 pounds (95,000 kilograms). Then, in agony, T-0 came…and left, but the rocket continued to sit motionless on the pad.

Video Credit: Relativity Space

Countdown clocks displayed an ominous 00:00:00, with a hold automatically ordered before TE retraction and liftoff. Engineers immediately headed to the vehicle’s health check to consider whether another attempt was feasible, with Mr. Walker noting that the abort was prompted by a Launch Commit Criteria (LCC) violation at T-0.5 seconds and that the team is “evaluating recycle opportunities”.

The clock recycled to a hold-point of T-45 minutes, before it resumed counting down after 3 pm EST, tracking a new T-0 of 3:55 pm EST, just five minutes before the window closed of Saturday. It was subsequently revised to 4 pm EST, right at the end of the window, as the specter of a second scrub loomed.

Terran-1 counts down to its last fruitless final T-0 of the day at 4 pm EST. Image Credit: Relativity Space

In an impressive turnaround that demonstrated the professionalism of the Relativity team, the clocks continued to count down to T-45 seconds, when another autonomous hold was called. This time, however, with an “urgent” launch dictated by Saturday’s closing window, there was no option to recycle and the attempt was scrubbed.

“Thanks for playing,” said Mr. Walker, repeating his phrase from Wednesday’s scrub. As this AmericaSpace story was being prepared, Relativity disclosed that “based on preliminary data analysis, the vehicle is healthy”, but had not yet announced a revised No Earlier Than (NET) target for its next Terran capture attempt -1 airborne.

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