Caltech Space Based Solar Power Cubesat Demo Flying December 2021

Dr. Rich Madonna gave a talk on Caltech’s SSPP (Space based solar power project) this past week.

Attendees of his talk are the leaders in the Space Based Solar Power community.

· Dr. Paul Jaffe (UMD)
· John Bucknell (Virtus Solis)
· Dr. Al Globus (UC San Jose)
· Skylar Hoffert (student)
· Dr. John Mankins (ex-NASA SSP head)
· Dr. Naoki Shinohara (Kyoto University)
· Dr. Xinbin Huo (China Academy of Space Technology)
· Dr. John Olds (Spaceworks)
· Charles Hall (Spaceworks)
· Jeff Madonna
· Rian Moriarty
· Michael Sanders (USNA)
· Haroon Oqab (Kepler Space Institute)
· Darel Preble (Space Solar Power Institute)
· Takayuki MATS
· Keith Henson

John Bucknell summarized Rich Madonna talk. Rich described progress since 2019.

Maintaining ‘membrane’ deploying concept – prior concept with deployable parabolic concentrators and antenna too expensive to manufacture

Switch to thin-film GaAs PV (Alta Devices/MicroLink)

Transparent conductor, PV, Ground Plane, RF/Power electronics and antenna layers about 1000microns thick

Improved deployment with a pneumatic inflator of membrane

Update power beaming from 2.45GHz to 10GHz

CMOS IC power amplifier, phase shifter, 16 antennas (3x3mm) now in 8th generation

Built and testing printed flexible 256 antenna transmitter

SW compensation for shape of the antenna, based upon exciting one antenna and rest receiving to triangulate the position

System Engineering

Improved availability of power transmission from 45% to 75%+ by moving to dual face operation (PV or RF from both sides of membrane)

LCOE-based analysis of engineering assumptions

Evaluated GEO and MEO orbital constellations, recognizing GEO is crowded

15 year life assumed

Orbital demo at end of year (2021). It is a rideshare on Momentus Vigoride demo mission (6 month duration).

Satellite Today reported that Momentus would launch the Caltech Space based solar mission.

Momentus has a contract for its second customer on its hosted payload service, and will host a payload from the California Institute of Technology (Caltech), called SSPD-1 at the end of next year. SSPD-1, which will demonstrate a wireless power transmission and a new deployable structure, is set to launch on Momentus’ Vigoride orbital transfer vehicle in December of 2021, and operate onboard the vehicle for about six months.

The hosted payload service is a new offering from Momentus, which is gearing up for the first flight of its orbital transfer vehicle, Vigoride, on SpaceX’s upcoming rideshare mission in 2021.

The Caltech space-based solar concept is based on the modular assembly of ultralight, foldable, 2D integrated elements. Integration of solar power and RF conversion in one element avoids a power distribution network throughout the structure, further reducing weight and complexity. This concept enables scalability and mitigates local element failure impact on other parts of the system.

In May 2017, Caltech had the first ultralight integrated prototype collecting solar power and wirelessly transmitting it is demonstrated at Caltech. The prototype has an aeral density of 1.5 kg/m2, more than 10x lighter than previous examples. This modular element can be repeated over an arbitrary area to form a large aperture which could be placed in orbit to collect sunlight and transmit power to any location.

In December 2017, Caltech had the second iteration functional prototype is demonstrated at Caltech. This prototype was 33% lighter than the first version, achieving areal density of less than 1 kg/m2. It integrates photovoltaics and power transfer circuitry and incorporates beam steering.

Dr Richard Madonna published a June 2019 summary of the Space Solar Power Initiative. He gave a talk at the National Space Society International Space Development Conference in 2019.

Caltech/Northrop Grumman Space Solar Power Initiative (SSPI) was a three-year effort to mature technological concepts associated with an innovative, ultra-light weight design for a satellite capable of converting solar energy to radiofrequency energy and beaming it to earth to power electrical grids. The presentation summarizes these efforts and describes how the lessons learned help shape the current Caltech Space Solar Power Project.

SOURCES- Caltech, Google Groups Space Based Solar Power, Satellite Today
Written By Brian Wang,