Posted by KeighleyAstro on Nov 1, 2024 in Main |

The September monthly meeting of Keighley astronomical society was the first in the 2024/25 season. The guest speaker was Dr Viktor Doychinov from the Renduchintala Centre for Space AI at the university of Bradford.

Dr Doychinov’s presentation was about the work that he does with his colleagues into the development of very small satellites. These are sometimes referred to as cube satellites; Dr Doychinov called them ‘Pocket sized’ satellites.

Dr Doychinov opened his presentation by outlining how the ‘Centre for Space’ at the university came about. A former student at the university of Bradford; Dr Venkata Murthy Reduchintala donated £2 million to set up and fund the centre, which bears his name in it’s title.

Dr Reduchintala studied at the University from 1988 to 1991 and went on to become chief engineering officer at Microchip Company ‘Intel’ in California. Speaking when the centre was opened in 2022 Dr Reduchintala said “I’ve reached a point in my life where I’d like to return in kind what Bradford has given me, which is a foundation on which I built my career.”

“I am really happy to be able to give back to the University in an area which is of strategic importance to them.

The plan was to give Bradford something unique to exploit on a national and global forum but also to exploit the talents of the academic and student pool that exists there.

Dr Doychinov pointed out that we will continue to see technology used in ways that will improve people’s lives. For example, we all take things like satellite communications for granted, the way we look at real-time transmissions around the globe, and the way we use ‘AI’ through agents such as Alexa or Siri, so just think what we can achieve in the next five years as those technologies move to the next stage.

Space technology is critical for tackling some of society’s biggest challenges, he explained. Such as climate change, natural disasters, world poverty, the digital divide, and a rapidly increasing data consumption and demand for ubiquitous broadband connectivity.

The Bradford-Renduchintala Centre for Space AI of the University of Bradford, brings together a multidisciplinary team of experts from academia and industry to deliver research and training that drive a low-cost and sustainable exploitation of space to meet some of these challenges.

So what are the pocket sized satellites they are developing?

Basically they are a type of miniaturised satellite for space research that usually has a size of cube with 5cm sides (one eighth the volume of a CubeSat), has a mass of no more than 250 grams, and typically uses commercial off-the-shelf components for its electronics.
Beginning in 2009, Morehead State University (MSU) and Kentucky Space developed the Pocket Qube specifications to help universities worldwide to perform space science and exploration. While the bulk of development comes from academia, several companies build miniaturised satellites, such as Fossa Systems and Alba Orbital.

These projects have even been the subject of kick starter campaigns, and is also popular with amateur radio satellite builders. The Pocket Qube specification accomplishes several high-level goals. Simplification makes it possible to design and produce a workable satellite at low cost. Encapsulation of the launcher-payload interface takes away the prohibitive amount of managerial work previously required for mating a piggyback satellite with its launcher. Unification among payloads and launchers enables quick exchanges of payloads and utilisation of launch opportunities on short notice.

Pocket Qube is similar to CubeSat in this regard.
The standard was first proposed by Professor Bob Twiggs of Morehead State University, and the intention was for a satellite, which could fit in a pocket, hence the name PocketQube.

A small satellite, miniaturised satellite, or smallsat is a satellite of low mass and size, usually under 1,200 kg (2,600 lb). While all such satellites can be referred to as “small”, different classifications are used to categorize them based on mass. Satellites can be built small to reduce the large economic cost of launch vehicles and the costs associated with construction. Miniature satellites, especially in large numbers, may be more useful than fewer, larger ones for some purposes – for example, gathering of scientific data and radio relay. Technical challenges in the construction of small satellites may include the lack of sufficient power storage or of room for a propulsion system.

Dr Doychinov explained that the rationale for miniaturising satellites is to reduce the cost; heavier satellites require larger rockets with greater thrust that also have greater cost to finance. In contrast, smaller and lighter satellites require smaller and cheaper launch vehicles and can sometimes be launched in multiples. They can also be launched ‘piggyback’, using excess capacity on larger launch vehicles. Miniaturised satellites allow for cheaper designs and ease of mass production.

Another major reason for developing small satellites is the opportunity to enable missions that a larger satellite could not accomplish, such as:-

Constellations for low data rate communications.
Using formations to gather data from multiple points.
In-orbit inspection of larger satellites.
University-related research.
Testing or qualifying new hardware before using it on a more expensive satellite.

Although smallsats have traditionally been launched as secondary payloads on larger launch vehicles, a number of companies began development of launch vehicles specifically targeted at the smallsat market. In particular, with larger numbers of smallsats flying, the secondary payload paradigm does not provide the specificity required for many small satellites that have unique orbital and launch-timing requirements.

In 2018, the two Mars Cube One microsats (massing just 13.5 kg (30 lb) each) became the first CubeSats to leave Earth orbit for use in interplanetary space. They flew on their way to Mars alongside the successful Mars ‘InSight’ lander mission. The two microsats accomplished a flyby of Mars in November 2018, and both continued communicating with ground stations on Earth through late December. Both went silent by early January 2019.

A number of commercial and military-contractor companies are currently developing microsatellite launch vehicles to perform the increasingly targeted launch requirements of microsatellites. While microsatellites have been carried to space for many years as secondary payloads aboard larger launchers, the secondary payload paradigm does not provide the specificity required for many increasingly sophisticated small satellites that have unique orbital and launch-timing requirements.

In July 2012, Virgin Orbit announced ‘LauncherOne’, an orbital launch vehicle designed to launch “smallsat” primary payloads of 100 kg (220 lb) into low Earth orbit, with launches projected to begin in 2016. Several commercial customers have already contracted for launches.

Nanosatellites are increasingly capable of performing commercial missions that previously required microsatellites. For example, a 6U CubeSat standard has been proposed to enable a satellite constellation of thirty five 8 kg (18 lb) Earth-imaging satellites to replace a constellation of five 156 kg (344 lb) RapidEye Earth-imaging satellites, at the same mission cost, with significantly increased revisit times: every area of the globe can be imaged every 3.5 hours rather than the once per 24 hours with the RapidEye constellation. More rapid revisit times are a significant improvement for nations performing disaster response, which was the purpose of the RapidEye constellation. Additionally, the nanosat option would allow more nations to own their own satellite for off-peak (non-disaster) imaging data collection. As costs lower and production times shorten, nanosatellites are becoming increasingly feasible ventures for companies.

In the ten years of nanosat launches prior to 2014, only 75 nanosats were launched. Launch rates picked up substantially when in the three-month period from November 2013–January 2014 94, nanosats were launched.

One challenge of using nanosats has been the economic delivery of such small satellites to anywhere beyond low Earth orbit. By late 2014, proposals were being developed for larger spacecraft specifically designed to deliver swarms of nanosats to trajectories that are beyond Earth orbit for applications such as exploring distant asteroids.

Dr Doychinov stated that the ‘pocket cube’ prototype that has been developed at Bradford is about the same size as a Rubik’s Cube – academics are currently working on the real one, which will contain an array of sensors including a camera, temperature sensor, GPS module and accelerometer. They had hoped to have one launched this year but this has been postponed until the autumn of 2025