Gilmours Eris fails during maiden launch, but positives can be found

Date:
Wed, 30 Jul 2025 17:07:46 +0000

Description:
The first Australian-built Orbital Rocket just took flight for the first time
but it The post Gilmours Eris fails during maiden launch, but positives can be found appeared first on NASASpaceFlight.com .

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The first Australian-built Orbital Rocket just took flight for the first time
but it didnt quite make it to orbit. After months of regulatory setbacks, weather delays, and the accidental separation of the fairings while still on the ground, Gilmour Spaces 3-stage Eris launch vehicle finally took off from the Bowen Orbital Spaceport on Wednesday morning, local time.



Issues occurred not even a second later, as one of its engines started to
lose thrust. The 30-metric-tonne rocket then started translating in the direction of the failed engine, indicating that it was producing very little to no thrust whatsoever.

Each of the four Sirius engines on the first stage produces 115 kilonewtons
of thrust, as of the most recent data provided during the final qualification test in 2022. In a nominal scenario, this would give Eris a thrust-to-weight ratio of 1.5 at lift-off, which was observed during the initial second of rising into the air.

Losing one of the four engines likely resulted in the thrust-to-weight ratio dropping to 1.2, barely enough to keep the rocket slowly climbing, as seen in the video provided by Gilmour Space. Liftoff completed, launch tower cleared, stage 1 tested. Awesome result for a first test launch. pic.twitter.com/EYbNbGDz3l

Gilmour Space (@GilmourSpace) July 30, 2025



The three remaining engines are also not symmetrically placed around the center of mass, resulting in the powerslide.

Approximately nine seconds after liftoff, with the vehicle slowly climbing, some white gases are observed being quickly ejected from the aft end of the vehicle. Unfortunately, this is on the opposite side of the rocket for the close-up camera, but it simultaneously resulted in the vehicle slowly falling to the ground. Eris lifts off the pad on its maiden launch attempt (Credit: Gilmour Space)

This is indicative of a second engine failure leaving only two running. This reduces the thrust-to-weight ratio down to 0.78 or in other words, there is not enough thrust to keep the rocket going uphill. There is still enough thrust to stop it from dropping down to the ground straight away, which is
why the video shows this slow, graceful, accidental propulsive landing until the vehicle hits the ground and tips over.

The fact that engines failed on the flight was confirmed by the Head of Avionics at Gilmour on X, but did not confirm which engines failed. It should also be noted that the Sirius engines on the first stage cant gimbal, or
steer themselves to point the rocket. Instead, it uses reaction control thrusters for steering.

One item of interest was the lack of a fireball when the rocket crashed to
the ground. That could be explained by the fact that the first two stages are hybrid, but this is speculation. Glimour Space drone shot

However, the vehicles Stage 1 and Stage 2 use liquid hydrogen peroxide as the oxidizer, and a solid fuel as the fuel. There is the possibility that because of the slower touchdown and solid propellant, a rupture of the tanks was minimized, until the vehicle tipped over and the Kerosene-Oxygen third stage impacted the ground.

Next up will be Flight 2, which will follow a huge data review. Gilmour says that that is currently scheduled for within six to eight months. That would
be an impressive turnaround, but positives can be found with this failure, such as how half of the engines failed, Eris managed to keep itself pointing upright during the entire, albeit short, flight. This will add confidence in Gilmours Guidance, Navigation, and Control systems.



The post Gilmours Eris fails during maiden launch, but positives can be found appeared first on NASASpaceFlight.com .



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Link to news story: https://www.nasaspaceflight.com/2025/07/gilmours-eris-but-positives/


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