| Pathfinder Technology Demonstrator | |
| Mission Type: | Technology demonstration |
| Operator: | NASA |
| Mission Duration: | 90 days (planned) |
| Spacecraft: | PTD-1 → PTD-5 |
| Spacecraft Type: | 6U CubeSat |
| Spacecraft Bus: | Tyvak |
| Manufacturer: | Ames Research Center and Glenn Research Center |
| Launch Mass: | [1] |
| Dimensions: | 30 × 20 × 10 cm |
| Power: | 65 watts |
| Launch Date: | 24 January 2021 (PTD-1) [2] |
| Launch Rocket: | Falcon 9 |
| Launch Site: | CCAFS, |
| Launch Contractor: | SpaceX |
| Orbit Reference: | Geocentric orbit |
| Orbit Regime: | Low Earth orbit |
| Orbit Altitude: | Sun-synchronous orbit |
| Apsis: | gee |
NASA's Pathfinder Technology Demonstrator (PTD) Project is a series of tech demonstrations of technologies aboard a series of nanosatellites known as CubeSats, providing significant enhancements to the performance of these versatile spacecraft. Each of the five planned PTD missions consist of a 6-unit (6U) CubeSat with expandable solar arrays.[3]
Flight qualification and demonstration of these technologies carried aboard the PTD missions are expected to benefit future government and commercial missions. These include propulsion systems and sub-systems that stabilize and point the spacecraft to high accuracy in order to use a laser communications system capable of high-speed broadband.
The first mission, PTD-1, was scheduled for launch in December 2020 on a Falcon 9 rocket, from Cape Canaveral, as part of the ride-share ELaNa mission 35, launched on January 24th, 2021, and demonstrated HYDROS-C water-based propellant system. PTD-3 launched on May 25 2022 on the SpaceX Transporter-5 rideshare and demonstrated the TBIRD infrared communication system.[4]
The Pathfinder Technology Demonstrator (PTD) Project is led by NASA's Ames Research Center in California, in collaboration with NASA's Glenn Research Center in Ohio. The PTD project is managed and funded by NASA's Small Spacecraft Technology Program (SSTP) within the Space Technology Mission Directorate. The overall goal is to test the physics of key new technologies in order to enhance small spacecraft and make them able to reach new destinations and operate in new environments.[5] [6] These technologies will be tested in low Earth orbit for potential future application in small spacecraft operating in Earth orbit or in deep space.[6] Technologies demonstrated by PTD flights may be applicable and scalable to larger spacecraft.[6]
The project plans to fly five 6U CubeSat orbital missions, coded PTD-1 through PTD-5, at 6-month intervals, each flight assessing different technologies.[7] Each mission will have a 90-day lifetime after it is released in low Earth orbit.[5] Each spacecraft will include different test payloads such as propulsion systems for orbital station-keeping, maneuvering and interplanetary transit, laser high bandwidth communications, or high precision attitude control (orientation) systems to stabilize the spacecraft and point the designated instruments with high accuracy.[5] [6]
Examples of novel systems to be tested are an electrospray thruster, water-based propulsion, and a very precise attitude control system.[5]
A Request for Proposal (RFP) NNA16574335R was issued, on 12 February 2016, for the delivery of a spaceflight qualified 6U CubeSat spacecraft to be operated by NASA for its Pathfinder Technology Demonstrator (PTD) Project to accommodate technology subsystems, hereafter referred to as the payload. One flight demonstration is planned for a low thrust propulsion system with options for four follow-on technology demonstrations. Follow‐on missions may include payloads such as higher thrust propulsion systems or payloads such as optical communications or high precision attitude determination and control systems. Request for proposal response date: 4 April 2016.[5]
The PTD-1 spacecraft is currently under development and fabrication. It will demonstrate a propulsion system with a water-based propellant obtained from electrolysis of water. While in orbit, the system separates onboard water into hydrogen and oxygen propellants by applying an electric current through the water. PTD-1 is scheduled for launch in December 2020 as part of the ride-share ELaNa mission 35 on board a Falcon 9 rocket.[11]
PTD-1 launched January 24th 2021 on SpaceX rideshare Transporter-1 mission.
HYDROS is a hybrid chemical/electrical technology to provide propulsion using water. It uses an electrolysis cell to split water propellant into gaseous hydrogen and oxygen that are stored under pressure in separate tanks. The system then burns the hydrogen and oxygen mix in a simple thruster nozzle to provide up to 1 Newton and a specific impulse of 258 seconds. This propulsion system is being developed by Tethers Unlimited, Inc.
In pure water, at the negatively charged cathode, a reduction reaction takes place, with electrons (e−) from the cathode being given to hydrogen cations to form hydrogen gas. The half reaction, balanced with acid, is:
Reduction at cathode: 2 H+ (Aqueous solution) + 2e− → H2 (gas)
At the positively charged anode, an oxidation reaction occurs, generating oxygen gas and giving electrons to the anode to complete the circuit:
Oxidation at anode: 2 H2O (liquid) → O2 (gas) + 4 H+ (aqueous solution) + 4e−
Overall reaction: 2 H2O (liquid) → 2 H2 (gas) + O2 (gas)
The propulsion system uses the electricity generated by the solar arrays to power the miniature water electrolysis. The demonstration will test propulsion performance through programmed changes in spacecraft velocity and altitude.
PTD-2 is a 6U CubeSat technology demonstration mission to demonstrate an improved attitude determination and control system that was developed under the Tipping Point Program. The HyperXACT design will provide 5X improvement in reliability and pointing over the many state of the art systems whilst maintaining the 1/2 U form factor.[12]
PTD-3, a 6U cubesat, launched on May 25 2022 on SpaceX's Transporter-5 rideshare mission, includes the 3U TeraByte InfraRed Delivery (TBIRD) laser communications test.[13] [14] TBIRD will send data at 200 Gbps from LEO to ground stations.[15] By Dec 2022, TBIRD demonstrated 100 Gbps data transfers from a 300 mile orbit to Earth, and plans to test 200-1,000 Gbps.[16] On April 28, 2023, 200 gigabit per second (Gbps) throughput was achieved.[17]
A 6U cubesat to demonstrate the Lightweight Integrated Solar Array and anTenna (LISA-T), a very high-power, low-volume deployable solar array with an integrated antenna. LISA-T is being developed by NASA’s Marshall Space Flight Center in Huntsville, Alabama. LISA-T offers lower mass and stored volume as well as a greater power per unit mass compared to current available solar array technology. As of December 2023, no launch date is set. The nanosatellite will be launched along with PTD-R on SpaceX's Transporter-11 mission out of Vandenberg Space Force Base.[18] [19]