Pathfinder Technology Demonstrator
NASA's Pathfinder Technology Demonstrator (PTD) project will test the operation of a variety of novel technologies on a type 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.
Flight qualification and demonstration of these technologies 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, is scheduled for launch in December 2020 on a Falcon 9 rocket as part of the ride-share ELaNa Mission 35.[1]
Overview
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 (SST) program 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.[2][3] These technologies will be tested in low Earth orbit for potential future application in small spacecraft operating in Earth orbit or in deep space.[3] Technologies demonstrated by PTD flights may be applicable and scalable to larger spacecraft.[3]
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.[4] Each mission will have a 90-day lifetime after it is released in low Earth orbit.[2] 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.[2][3]
| Mission type | Technology demonstration |
|---|---|
| Operator | NASA |
| Mission duration | 90 days (planned) |
| Spacecraft properties | |
| Spacecraft | PTD-1 → PTD-5 |
| Spacecraft type | 6U CubeSat |
| Bus | Tyvak |
| Manufacturer | Ames Research Center and Glenn Research Center |
| Launch mass | 11 kg (24 lb) [5] |
| Dimensions | 30 × 20 × 10 cm |
| Power | 65 W [5] |
| Orbital parameters | |
| Reference system | Geocentric |
| Regime | Low Earth |
Technology under assessment
Examples of novel systems to be tested are an electrospray thruster, water-based propulsion, and a very precise attitude control system.[2]
- BET-100 μN is a colloid thruster fabricated by Busek that was successfully flown in the ESA LISA Pathfinder mission in 2016.[6] Each thruster requires less than 6 W of power.
- Attitude Determination and Control System (ADCS), uses Blue Canyon's Hyper-XACT ADCS. The package incorporates a star tracker, 3-4 reaction wheels, three torque rods, a magnetometer, an inertial measurement unit, and up to four Sun sensors.
- 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 for burning in a thruster nozzle. This propulsion system is being developed by Tethers Unlimited, Inc.
- The MPS-130 engine by Aerojet Rocketdyne burns a novel ionic liquid propellant called hydroxylammonium nitrate (NH3OHNO3). It is a fuel/oxidizer blend also known as AF-M315E that is about 50% more efficient than traditional hydrazine, and is non-toxic.[2] Aerojet Rocketdyne tested this engine and fuel on a mission called Green Propellant Infusion Mission,[7] launched aboard a SpaceX Falcon Heavy rocket on 25 June 2019, on a test mission called Space Test Program 2.
- The PTD project will also evaluate the commercial Globalstar communications network for low cost in-space communications for sending commands to spacecraft in low Earth orbit. Each of the five planned spacecraft will incorporate a Globalstar GSP-1720 Duplex Modem.[3][8]
PTD-1
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 August 2020 as part of the ride-share ELaNa Mission 35 on board a Falcon 9 rocket.[1]
Propulsion
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:
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(l) → O2(g) + 4 H+(aq) + 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.
See also
- Cislunar Explorers, another spacecraft using water electrolysis to generate propellant
- World Is Not Enough, a spacecraft propulsion system using water harvested in-situ
References
- "Upcoming ElaNa CubeSat Launches". NASA. Retrieved May 11, 2020.
- Pathfinder Technology Demonstrator. Small Satellite Conference 2016. Vanessa Kuroda, Communications Subsystem Lead April 20-22, 2016 CalPoly CubeSat Workshop.
- NASA's Pathfinder Technology Demonstrator Elwood F. Agasid, Roger C. Hunter, Christopher E. Baker, John Marmie, Darin Foreman. John Hanson, Mirabel Hill. Small Satellite Conference 2017. SSC17-III-02
- Propulsion Technology Demonstrator. Demonstrating Novel CubeSat Technologies in Low Earth Orbit. NASA Technical Reports Server. Marmie, John; Martinez, Andres; Petro, Andrew. August 8, 2015. Document ID: 20150016065
- Pathfinder Technology Demonstrator: Demonstrating Novel CubeSat Technologies in Low Earth Orbit. (PDF) Elwood F. Agasid, Roger C. Hunter, Christopher E. Baker. NASA Ames. 13 March 2018.
- Rovey, J. "Propulsion and Energy: Electric Propulsion (Year in Review, 2009)" (PDF). Aerospace America, December 2009, p. 44. Archived from the original (PDF) on 2015-12-08. Retrieved 2019-01-21.
- Mohon, Lee (2013). "Technology Demonstration Missions: Green Propellant Infusion Mission (GPIM)". NASA. Retrieved 2014-02-27.
- Pathfinder Technology Demonstrator: GlobalStar Testing and Results. (PDF) Vanessa Kuroda Communications Subsystem Lead April 20-22, 2016. CalPoly CubeSat Workshop.
External links
- PTD-1 NASA video at YouTube