Job Description

ReOrbit is looking for a Payload Software Engineer to develop the software that powers our regenerative on-board 5G Non-Terrestrial Network (NTN) payload.

As our Payload Software Engineer, you will work at the intersection of 5G RAN software and spacecraft avionics, developing and integrating the gNB protocol stack that enables direct-to-device connectivity from Low Earth Orbit.You will play a key role in ReOrbit's OrbitCloud regenerative on-board payload for our NTN Direct-to-Device programme, supporting 5G services including VoNR and NB-IoT connectivity to unmodified handsets over an S-band service link.

It's an exciting chance to join a dynamic start-up, with the opportunity to make a real impact, to reach our goal of pushing the boundaries of space data transfer.

Responsibilities

• Design, implement and integrate the gNB Layer 2 protocol stack, including MAC, RLC, PDCP and SDAP, for a regenerative on-board 5G NTN payload.

• Develop and adapt Layer 3 functionality, including RRC and NGAP/N2 signalling, for Low Earth Orbit operation.

• Implement and integrate relevant 3GPP Release 17 and Release 18 NTN features, including timing advance, HARQ adaptation, feeder-link switchover and mobility procedures.

• Port, optimise and harden the L2/L3 stack for embedded multicore Arm platforms operating under strict power, memory and real-time constraints.

• Integrate L2/L3 functionality with the PHY/DFE partition using FAPI, nFAPI or equivalent split interfaces.

• Integrate the protocol stack with on-board core network functions supporting services such as VoNR and NB-IoT.

• Define and execute unit, integration and conformance testing using protocol testers, UE emulators and Hardware-in-the-Loop setups.

• Debug and troubleshoot complex protocol, integration and performance issues using protocol analysers, logs and live system data.

• Support in-orbit validation and troubleshooting of deployed payload software and network functionality.

• Contribute to make-versus-buy decisions and technical evaluations of O-RAN and third-party supplier stacks.

• Develop and support reliability and fault-mitigation mechanisms for COTS processors operating in LEO, including watchdogs, fast reboot, ECC and fault containment strategies.

Skills and Requirements

• 5+ years of hands-on experience developing 5G NR gNB software, with strong expertise in Layer 2 and/or Layer 3 protocols including MAC, RLC, PDCP, SDAP and RRC.

• Strong C/C++ development experience in embedded Linux environments, including real-time multicore Arm platforms and performance optimisation under tight power and memory constraints.

• Deep working knowledge of 3GPP RAN specifications, including the 38.300 series, and a strong understanding of 5G NR scheduler design.

• Experience integrating L2/L3 with PHY through FAPI, nFAPI or a comparable split architecture, with exposure to high-performance data-plane frameworks such as DPDK or equivalent.

• Strong debugging and system integration skills, including experience using protocol analysers, UE emulators, HIL environments and log-based troubleshooting of live RAN systems.

• Experience or strong interest in 3GPP Release 17/18 NTN features, including Doppler and timing compensation, extended timing advance, HARQ adaptation and satellite mobility procedures.

• Knowledge of NB-IoT, eMTC, VoNR or IMS interworking and QoS handling would be highly beneficial.

• Exposure to O-RAN architectures, including O-DU/O-CU splits and interfaces such as F1 and E2, as well as third-party RAN stack integration or evaluation.

• Familiarity with space, avionics or other high-reliability embedded environments, including COTS processor reliability, FDIR, fault containment and remote software updates, is a strong advantage.

• Experience with Layer 1 or PHY development is considered a plus.

What does ReOrbit do?

ReOrbit builds the foundation for the next generation of space applications by transforming satellites into truly intelligent, interconnected platforms, defined by software. Our satellite design philosophy revolves around the idea that satellites must network, communicate with each other and thus improve mission efficiency. How can this be achieved? Thanks to a flexible software-first architecture, where all these aspects are dealt with upfront in the mission concept, as integrated functionalities.

ReOrbit’s top-notch team of software engineers and system architects develop in-house software, procure hardware from the best-in-class suppliers, and seamlessly integrate the components to create flexible and secure satellites. Today, we are a rapidly growing company building a very strong multidisciplinary team to support our activities. We are headquartered in Helsinki, Finland with a subsidiaries in Bristol, UK, Bariloche, Argentina and Bengaluru, India.

Working at ReOrbit

At ReOrbit, we are focused on building a strong team as we believe nothing can be accomplished without innovative, humble and curious minds working together on a common goal. We’re all about fostering an inclusive, dynamic environment where equality and diversity are our strength.

We offer

• Challenging but rewarding environment – you will thrive if you are always reflecting on how to make things better. Your ideas will be heard.

• Ambitious and supportive network of people, who are motivated to change the space industry, bringing expertise from both classic and new space .

• Benefits such as lunch vouchers, events, parties, occupational health care and additional health insurance - but most importantly a possibility to be a part of a unique and diverse team, connected by similar mindset and sense of humor.

• We like to spend time together! You can choose activities whichever is to your liking – runOrbit, climbOrbit; become ping pong or board games champion.

• We support relocation and integration into Finnish society.

Join us in our journey of building software enabled satellites for secure communications
and, thus, creating the most compelling in space data flow company of the new space era.

The Company may require a security clearance for certain positions. Any such security clearance will be conducted in accordance with applicable law and the Company's relevant policies

For agencies: We do not accept unsolicited CVs for our open vacancies. Any CV sent to our team unsolicited will reserve us the right to pursue a candidate without obligation to the sender. All candidate submissions must be conducted through our official channels and in accordance with our terms of engagement.