Gilmour Space Technologies is performing final system checks before launching its homegrown Eris rocket. The vehicle is poised to become the first orbital launch from Australian soil by a sovereign-built vehicle when it makes its debut this week.
The Civil Aviation Safety Authority (CASA) approved the company’s maiden flight in late April, which Gilmour Space announced on May 4. A final sign-off from the Australian Space Agency was approved on May 13 and, following the identification of an issue in the ground support system during overnight checks, the launch attempt has now been moved 24 hours to the right. The current launch window opens no earlier than than 7:30 AM AEST on May 16 (21:30 UTC on May 15).
As with the SaxaVord site in the UK, regulatory approvals can be complicated and long-winded, especially for new launch sites. The Gold Coast-based company was granted a provisional launch permit last November and had previously intended to launch in mid-March. This was the first orbital launch permit issued by the space agency. While some regulatory paperwork remained outstanding, the preparations to launch were then delayed by Tropical Cyclone Alfred, which moved into the area.
The Bowen Orbital Spaceport is Australia’s first licensed commercial orbital launch facility. (Credit: Gilmour Space)
A small team of 25 staff was sent in advance of this month’s launch to the company’s Bowen Orbital Spaceport at Abbot Point, north of the coastal town of Bowen. They have since completed a launch readiness review for the debut mission, dubbed “TestFlight 1.” The picturesque site affords 20 to 65-degree, low to mid-inclination equatorial orbits. The spaceport was developed in agreement with the Juru traditional custodians of the land in late 2021 and officially opened last April.
Proudly “Australian-made” and bearing the country’s flag on its upper stages, Eris is a three-stage rocket. Comparable to Rocket Lab’s Electron, it stands a little taller than Electron at 25 m in height. The vehicle also has a slightly larger 1.5 m fairing and boasts a payload mass of up to 215 kg to a 500 km Sun-synchronous orbit, or 305 kg to 500 km equatorial orbits.
The first stage is propelled by four Sirius engines — a proprietary hybrid engine that uses a 3D-printed solid fuel grain and a Hydrogen Peroxide liquid oxidizer. The additive manufacturing approach allows for complex geometries within the grain, designed to optimize the fuel’s burn characteristics and improve engine performance.
Sirius hybrid engine qualification testing. (Credit: Gilmour Space)
Another single Sirius engine powers the second stage, while the third uses a Phoenix engine, which burns liquid propellants. A successful orbital launch would also be the first for a hybrid rocket design.
Both the vehicles and their engines are manufactured in-house, with expanded use of 3D printing. Gilmour Space selected EOS as its additive manufacturing partner in late 2023 as it transitioned beyond the prototyping stage.
TestFlight 1 will be the first orbital launch from Australian soil in over 50 years. Eris will fly on a northeasterly trajectory over the Coral Sea and hopes to reach low-Earth orbit (LEO) on its first attempt.
Eris is transported horizontally at Bowen Orbital Spaceport. (Credit: Gilmour Space)
To date, only two successful orbital launches have been conducted from Australia, the first of which took flight from the Woomera Test Range in South Australia in November 1967, when the nation’s first satellite was lofted atop a modified Redstone rocket. The launch of the Weapons Research Establishment Satellite (WRESAT) mission established Australia as the third country to launch a satellite into orbit from its own territory, following the Soviet Union and the United States. The United Kingdom’s Black Arrow then successfully launched the Prospero satellite into orbit from Woomera four years later in October 1971.
Since then, Australia has launched hundreds of suborbital missions, including sounding rockets for NASA missions from the Arnhem Space Centre in the Northern Territory and many others from the Whalers Way Orbital Launch Complex and Koonibba Test Range. The latter supported the launch of German company HyImpulse’s SR75 last May — another vehicle that utilizes hybrid propulsion and proprietary fuel grains.
Gilmour Space also builds its own satellites, and the company’s 100 kg modular ElaraSat bus is capable of delivering 72U of payload to orbit. The bus was selected by Perth-based LatConnect60 for a forthcoming demonstration mission that will use the short-wave infrared range to provide insights into methane and carbon emissions from space. This particular prototype satellite will be integrated in Gilmour Space’s Queensland facility, but then launched by Skyroot Aerospace in India.
Gilmour Space’s first suborbital launch of the RASTA Mk2 occurred nine years ago in July 2016. The flight demonstrated the company’s hybrid engine technology for the first time and was notable for being among the first of its kind to use a 3D-printed fuel grain.
The company is now offering its commercial and defense customers a suborbital test flight service, which will deliver payloads at hypersonic speeds in excess of Mach 5 — more than five times the speed of sound. This HyPeRsonic FLight Test (HPRFLT) service addresses the growing demand for the prototyping and testing of high-speed vehicles and materials, going beyond what ground-based tunnel testing and simulations can provide.
Render of Eris in Block 1 configuration (Credit: Gilmour Space)
A second Eris vehicle is already being built, incorporating some design improvements that could be further refined based on the results of the maiden flight. Further along the roadmap, Gilmour Space is planning for a Block 2 version of the vehicle that will feature higher performance, making Eris more akin to Firefly Aerospace’s Alpha vehicle. This version will deliver up to 1,000 kg to LEO and will be used for the company’s Caravan-1 rideshare mission. A medium-lift Eris Heavy is also planned, capable of lofting up to 4,000 kg to LEO and potentially even crew capsules.
Gilmour Space has several commercial agreements in place for future missions with operators of orbital transfer vehicles (OTV). The company signed its first European partnership agreement with rideshare specialist Exolaunch almost four years ago, which would give it access to low-inclination missions and unique orbits. The company also signed a memorandum of understanding (MOU) in February 2023 with Atomos Space. Through this MOU, Atomos will contract launch services aboard Eris. At the same time, the vehicle will also carry Atomos’ OTVs in the future, offering customers additional in-space transportation and orbit-raising services.
View of the Eris rocket on the pad at the spaceport in Bowen, Australia. (Credit: Gilmour Space)
Australia’s Department of Defence also contracted with Gilmour Space in 2022 to develop and launch a new G-class sovereign surveillance satellite — part of the government’s increased investment in space capabilities. A future all-Australian mission will additionally send two Mayla thermal infrared cameras to orbit. These were developed by Australian Astronomical Optics (AAO) at Macquarie University. Rather than develop space-grade cameras from scratch, the team has successfully modified an off-the-shelf camera for use in space. Potential applications of this space-based heat-detecting technology include the detection of bushfires.
New Zealand-based Frond Space Systems is supplying a lightweight and compact MICRO dragsail for Gilmour Space’s forthcoming MMS-1 satellite mission. This dragsail will be attached to a 100 kg microsatellite and will activate at the end of its five-year operational lifespan, accelerating its deorbit as part of the company’s commitment to the sustainable utilization of space.
Eris stands vertical against a scenic sky (Credit: Gilmour Space)
As with many new launch vehicles, the path to Eris’s debut launch has been longer than initially projected. The inaugural Eris rocket was fully integrated and moved into its vertical launch position in April 2024, and had completed its dress rehearsals before the end of 2024. Eris has been resting horizontally inside the Bowen spaceport’s Vehicle Assembly Building since then.
There are no plans to livestream the maiden launch, but the company promises that video will be shared following the launch attempt. As with SaxaVord’s spaceport, there are no immediate plans for on-site launch viewing. However, this will inevitably follow once the site has supported several launches, bringing an additional boost to the local economy.
#TestFlight1 Update:
𝗡𝗼 𝗹𝗮𝘂𝗻𝗰𝗵 𝘁𝗼𝗱𝗮𝘆. Our team identified an issue in the ground support system during overnight checks. We’re now in an extended hold to work through it.
Our next target is the Friday morning launch window. Stay tuned for updates. pic.twitter.com/4BeND79hKw
— Gilmour Space (@GilmourSpace) May 14, 2025
(Lead image: Eris is moved to its vertical position at Bowen Orbital Spaceport. Credit: Gilmour Space)
