Pathfinder Technology Demonstrator

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Pathfinder Technology Demonstrator
Mission typeTechnology demonstration
OperatorNASA
Mission duration90 days (planned)
Spacecraft properties
SpacecraftPTD-1 → PTD-5
Spacecraft type6U CubeSat
BusTyvak
ManufacturerAmes Research Center and
Glenn Research Center
Launch mass11 kg (24 lb) [1]
Dimensions30 × 20 × 10 cm
Power65 watts
Start of mission
Launch date16 December 2020 (planned) [2]
RocketFalcon 9
Launch siteCCAFS,
ContractorSpaceX
Orbital parameters
Reference systemGeocentric orbit
RegimeLow Earth orbit
AltitudeSun-synchronous orbit
 

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, from Cape Canaveral, as part of the ride-share ELaNa mission 35.[3]

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 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.[4][5] These technologies will be tested in low Earth orbit for potential future application in small spacecraft operating in Earth orbit or in deep space.[5] Technologies demonstrated by PTD flights may be applicable and scalable to larger spacecraft.[5]

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.[6] Each mission will have a 90-day lifetime after it is released in low Earth orbit.[4] 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.[4][5]

Technology under assessment[]

Examples of novel systems to be tested are an electrospray thruster, water-based propulsion, and a very precise attitude control system.[4]

  • 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 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.[5][9]

PTD-1[]

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.[4]

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.[3]

Propulsion[]

Further information: Electrolysis of water
Diagram showing the overall chemical equation.

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.


See also[]

References[]

  1. ^ "Pathfinder Technology Demonstrator: Demonstrating Novel CubeSat Technologies in Low Earth Orbit" (PDF). nasa.gov. NASA. 23 April 2018. Retrieved 10 October 2020. Public Domain This article incorporates text from this source, which is in the public domain.
  2. ^ "Launch Schedule". Spaceflight Now. 8 October 2020. Retrieved 10 October 2020.
  3. ^ a b "Upcoming ElaNa CubeSat Launches". NASA. 10 August 2020. Retrieved 10 October 2020. Public Domain This article incorporates text from this source, which is in the public domain.
  4. ^ a b c d e f "Pathfinder Technology Demonstrator, Small Satellite Conference 2016". NASA. 20–22 April 2016. Retrieved 10 October 2020. Public Domain This article incorporates text from this source, which is in the public domain.
  5. ^ a b c d e 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 Public Domain This article incorporates text from this source, which is in the public domain.
  6. ^ Propulsion Technology Demonstrator. Demonstrating Novel CubeSat Technologies in low Earth orbit; NASA Technical Reports Server; Marmie, John; Martinez, Andres; Petro, Andrew; 8 August 2015; Document ID: 20150016065 Public Domain This article incorporates text from this source, which is in the public domain.
  7. ^ Rovey, J. "Propulsion and Energy: Electric Propulsion (Year in Review, 2009)" (PDF). Aerospace America, December 2009, p. 44. Archived from the original (PDF) on 8 December 2015. Retrieved 10 October 2020.
  8. ^ Mohon, Lee (2013). "Technology Demonstration Missions: Green Propellant Infusion Mission (GPIM)". NASA. Retrieved 27 February 2014. Public Domain This article incorporates text from this source, which is in the public domain.
  9. ^ Pathfinder Technology Demonstrator: GlobalStar Testing and Results. (PDF) Vanessa Kuroda Communications Subsystem Lead, 20-22 April 2016, CalPoly CubeSat Workshop

External links[]

  • PTD-1 NASA video at YouTube
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