Aerospace and Electronic Systems - August 2019 - 22

Feature Article:

DOI. No. 10.1109/MAES.2019.2927897

The Sky is NOT the Limit Anymore: Future
Architecture of the Interplanetary Internet
Ahmad Alhilal, Tristan Braud, The Hong Kong University of Science and
Technology, Hong Kong
Pan Hui, The Hong Kong University of Science and Technology, Hong Kong
and University of Helsinki, Finland

INTRODUCTION
Space exploration is not only feeding human curiosity,
but also allows for scientific advancement in environmental research, and in finding natural resources [1].
Although media exposure reached its peak during the
Apollo programs, space research remains a very active
domain, with new exploration and observation missions
every year.
Following the Apollo program, public and private
organizations launched a wide variety of exploration missions with increasingly complex communication constrains. In 1977, NASA launched Voyagers 1 and 2 [2] to
explore Jupiter, Saturn, Uranus, and Neptune. In September 2007, Voyager 1 crossed the termination shock at
84 AU, which is more than twice the distance to Pluto.
The Voyager interstellar mission (VIM), an extension to
the 1977 Voyager mission, will explore the outermost
edge of the Sun's domain and beyond. Regarding nearby
planets, NASA launched several exploration rovers in
2004 and 2012, followed by the InSight lander in 2019.
Currently, six active satellites orbit around Mars, with primary purpose of studying the atmosphere, relay data for
other missions, or test key technologies for interplanetary
exploration [2]. Private companies are also starting to take
part in space exploration. SpaceX and Blue Origin were
founded to reduce the cost and increase the safety of the

Authors' current addresses: A. Alhilal, T. Braud, The
Hong Kong University of Science and Technology,
Kowloon 999077, Hong Kong. E-mail: (aalhilal@ust.hk).
P. Hui, The Hong Kong University of Science and
Technology, Kowloon 999077, Hong Kong, and also
with the University of Helsinki, Helsinki FI-00014,
Finland.
Manuscript received February 1, 2019, revised May 13,
2019, and ready for publication July 8, 2019.
Review handled by G. Fasano.
0885-8985/19/$26.00 ß 2019 IEEE
22

space flight, and aim for near-future Mars exploration.
Finally, in 2018, Luxembourg became the first country to
legislate for asteroid exploration and mining, opening
the way for a whole new space industry. However, each
mission operates independently, has its own dedicated
architecture, uses point-to-point communication, and is
dependent on operator-specific resources. In this paper,
we propose an interoperable infrastructure in a similar
fashion to the Internet at stellar scale to simplify the communication for upcoming space missions.
In recent years, space exploration managed to attract a
lot of media attention, resulting in a clear regain of interest
of the public for space exploration. As a consequence,
space agencies started to plan several ambitious missions
for the 22nd century, both manned and unmanned. These
missions require increasing communication capabilities,
proportional to their complexity. Such missions require a
reliable, scalable, and easy to deploy common communication infrastructure to transmit scientific data from the
outer space to the earth and back. The advantages of such
strategy are manifold.
1) Interoperability: It significantly reduces the cost of
communication and facilitates interagency cooperation. Future missions would benefit from sharing
resources.
2) Security: Organizations can work together toward a
reliable and secure infrastructure.
3) Increased bandwidth: Future missions will require a
higher bandwidth to provide increasing amounts of
data to the general audience.
4) Scalability: Since space exploration is an incremental process, it is more efficient to progressively scale
up the network instead of deploying all the resources at once.
5) Colonies: Several organizations envision definitive
Mars colonies. Interconnecting both planets'

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AUGUST 2019

Aerospace and Electronic Systems - August 2019

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