Introducing Sherpa-AC

The newest member of our Sherpa orbital transfer vehicle (OTV) family is ready to fly! 

Our first Sherpa-AC is scheduled to fly on Transporter 5, a SpaceX rideshare scheduled to launch soon out of Cape Canaveral, Florida. It will be carrying hosted payloads for Xona Space and NearSpace Launch. 

Sherpa-AC, named for its “Attitude Control” capabilities, augments our base free-flying Sherpa with key functionality including a flight computer, attitude knowledge & control and more, making it ideal for servicing hosted payloads on orbit. 

“For customers looking to demonstrate new technologies quickly, Sherpa-AC provides a platform to do so. It brings all the aspects of a bus allowing hosted payload customers to focus on their payload, while the Sherpa vehicle handles everything else.”

Bill Ross, Spaceflight’s Senior Manager of Engineering

Let’s take a closer look: 

Our family of Sherpa OTVs has been designed to bridge the gap between where a LV drops its satellites off and the satellites’ destination orbit. You can read more here about the various Sherpa configurations.

In addition to many Spaceflight customers wanting precise deployment to their own specific orbits, we’re also seeing an increasing demand for both orbital transfer to, and hosted payload operations in, higher Earth orbits and deep space. 

Sherpa has a high degree of modularity and can be configured with a variety of attitude control and propulsion options, enabling many different mission goals. Sherpa was designed with eventual deep space missions in mind. Whether a customer requires last-mile delivery services to Geostationary Earth Orbit (GEO), a spacecraft platform for hosted payloads in Low Earth Orbit (LEO), or anything in between, Sherpa is the right fit: nothing else on the market matches its performance at the small spacecraft scale.

Our base free-flier vehicle, Sherpa-FX, is the model on which all other models are based. It is primarily used for grouping more customer spacecraft into the volume limitations of a launch vehicle as a “port expander,” thereby reducing launch costs for those customers. As a reminder, Sherpa-FX includes a sequencer and 1-way communication system, but has no propulsion, attitude control, or ability to actively service hosted payloads. It can deploy up to 16 customer spacecraft, monitor the deployments, and relay mission telemetry to Spaceflight. 

Sherpa-AC is the next in line, and augments the base Sherpa with key capabilities that make it ideal for servicing hosted payloads. One of the key aspects of Sherpa-AC is that it has attitude control. Not only can the attitude knowledge be shared with the hosted payload, but attitude control is available to support pointing or tracking. 

In addition to the Sherpa-FX functionality, Sherpa-AC includes: 

  • Flight computer
  • Attitude knowledge & control
  • An electrical power system (solar panels, batteries, etc.)
  • 2-way RF communications 
  • Basic thermal control (e.g. heaters and RTDs)

Power is provided by the Sherpa-AC batteries and solar panels. The command and control system has dedicated data storage for hosted payload data. This can be used to store data for later downlink. Live links can also be established during ground station passes to directly communicate with hosted payload. Multiple radio options are available depending on the required data rates.

With attitude control also comes thermal control. This is achieved with heaters and temperature measurement capability. This can be done by the hosted payload or it can be handled by Sherpa-AC to target a temperature window.

In addition to deploying multiple satellites, Sherpa-AC is well-suited for accommodating hosted payloads in LEO for up to a year.  

We’re excited to see Sherpa-AC fly soon and serve more customers’ unique needs on orbit. Follow along with our status updates on Twitter @spaceflightinc.

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