Introduction
The International Space Station (ISS) is an exclusive scientific podium
and an orbiting laboratory that has facilitated interdisciplinary
researchers in 106 countries to conduct various in vitro trials
in microgravity. Although each ISS partner has diverse scientific
objectives, the aggregate aim is to encompass the experience and
knowledge garnered to benefit all humankind [1, 2]. This is
predominantly factual for nurturing medicinal plants in ISS for
scarce-drug discoveries for the benefits of humanity [3]. This
article is a part of the scientific odyssey that resulted from a
collaboration among members from various research groups from physical,
chemical, material and biological sciences. Literature review reveals
that through fundamental research and development a few products and
services derived from space station activities are entering the souk and
furthering healthy and peaceful life on Earth [1], which is
motivating us to propose more challenging research in ISS. It is evident
from the executive summary of ISS, which encapsulates the achievements
of innovative research on the orbiting laboratory that had created a
positive impact on the quality of life on Earth and the future scope of
the interdisciplinary researches globally for creating an impact on
scientific advancement [1-16]. Herein we conduct theoretical studies
for providing the proof of the concept of space debris recycling and
energy conversion system in a microgravity environment with an intention
to carry out real-time experiments in the space platform through the
multi-national collaboration with wide scope and benefits to humanity.
The growing utilization of outer space for the advancement of the
standard of living and hunt for wisdom has led to the accretion of space
debris or space junk in high-density satellites orbits. Various reports
and industrial engineering data on the usefulness of the prevailing
debris extenuation methods are inadequate for a realistic conclusion
[4-16]. J.-C. Liou et al. [4-8] reported that as the space
debris volume remains to rise over time due to the global space
activities in recent years, there is a need to update the debris
alleviation normal exercises to stimulate competent and active practices
to better abate the risks from space debris for the benign manoeuvres of
future space missions. Literature review reveals that the frequency
variations of orbital launches are due to the in-house reasons in the
participating countries [17]. The current trend of rocket launches
globally shows that in the next few decades’ large volumes of space
debris will be in orbit, which will create a serious threat to future
missions. It is comprehended by other investigators that albeit all
upcoming space launches are called off, the space debris already exist
will be tendering threats for numerous decades to come before all of
them re-enter earth and burn off [14-17]. Deepaa Anandhi et al.,
[17] reported the need for an urgent action on the space debris
mitigation independently or jointly by the various beneficiary
organizations utilizing the orbital space for meeting the future global
needs. Though numerous on going debris de-orbiting programs are intact,
the engineering data on the usefulness of the prevailing debris
extenuation procedures are inadequate for a reliable judgment [18].
Briefly, an enhanced volume of space debris has become a menace to live
satellites, ISS and various space missions. Although many studies have
been reported over the decades on space debris management and
alleviation, the space system designers reported that there are no
foolproof techniques for tracking and mitigation of space debris having
the object size between 1 cm and 10 cm, which could cause significant
damage to live satellites, future space vehicles and the ISS [18].
Although every space agency is persuaded to reduce space debris whenever
feasible by using their state-of-the-art modus operandi, there may be
some parts that would be liberated and orbiting for obvious causes
beyond control. This situation was observed by many space agencies when
a physical part of the space vehicle was departed in geostationary
transfer orbit (GTO) during a multiple payload mission [10].
Therefore, it is essential, rather enviable, perhaps predestined for
inventing lucrative and efficient methods of space debris mitigation.
United Nations (UN) Committee on the peaceful uses of outer space
reported that the most challenging part of the space operations is the
collision avoidance. It also reported that the space debris curing
issues certainly entails joint action by all participants [11].
The central idea of the space broom governed by the dual-head
electromagnetic (DHEM) device [19], is to mitigate the intermediate
size of the space debris object, which could otherwise pierce holes in
the structure of the ISS and live satellites, particularly in the low
earth orbit. It is estimated that the space debris could crash any space
vehicle at a velocity greater than 48,280 km/hr [18]. Hao Jiang et
al. [20] carried out tests in microgravity and reported that robotic
grippers based on dry adhesion are a workable option for purging space
debris in low Earth orbit. The DHEM space broom with variable sweeping
speed developed by V.R.Sanal Kumar et al. [19] could be a useful
method for the space debris mitigation and its collection for recycling
it in the orbiting space lab through the lucrative energy conversion
methods. The DHEM space broom could be redesigned for capturing the
inactive satellites, rocket fragmentation debris, and other
non-functional objects or debris pieces from the low earth orbit. The
environmental report (2019) of the European Space Agency (ESA)
highlighted that space debris mitigation requires a level playing field
to achieve long-term stability. The ESA highlighted in its annual space
environment report (2019) that the production of space debris via
impacts and blasts in orbit could lead to an exponential growth in the
volume of artificial objects in space [21]. Therefore, the menace of
space debris to the future of spaceflight, united with the closely
world-wide embracing of the U.N convention (1972) on global
accountability for damage caused by space objects, created the need for
a set of internationally accepted space debris mitigation measures
[22]. Recently the ESA emphasized the need of world-wide devotion to
invoking space debris alleviation measures lucratively. The accessible
global literature reveals that no one attempted yet
(2020), the recycling technique to change the debris into
powders in the ISS for multiple applications [14, 15].
Report (2019) reveals that India contributed around 400 pieces of
orbital debris through their anti-satellite missile test (ASAT), which
increases the risk of threat to the ISS on the order of 44 % [18].
Since the test was done in a low altitude to restrict the orbital
lifespan of ensuing debris, the space agency claimed that whatever
debris that is generated would decay and fall back onto the earth within
weeks and the ISS will not be at risk, as it is in the higher orbit.
However, there are possibilities of the orbital lifting of space debris
due to missile impact, which could create threat to the ISS. Therefore,
in future such tests must be avoided by all the space agencies or must
be done with caution as the ISS is a human inhabitant and an orbiting
laboratory, which is to be protected with zero-risk. It is well known
that the non-responsive satellites are the high-risk space debris to the
operational satellites and the ISS. The primary structure of most of the
satellites consists of aluminum, beryllium, stainless steel and
titanium. The appendage booms, antenna dishes (made of aluminum /
steel), platforms, solar panels (made of silicon / germanium), and
support trusses, are common secondary structures. The mounting brackets,
cable supports, copper wiring and connector panels, electronic boxes,
and silicon made printed circuit board (PCB) are categorized as tertiary
structures [23]. Literature review reveals that Aluminum 6061, a
potential fuel for solid propellant, is used as the primary structure of
the CubeSats [24]. Therefore, any combined method to mitigate and
recycle the space debris with an innovative energy conversion method
could create a win-win situation, which is attempted herein.
In this paper a cogent conceptual method has been proposed for
converting the space debris into lucrative solid fuels in the ISS with
artificial gravitational field. Note that M.Tajmar [25] reported two
different system designs that could generate an artificial gravitational
field using frame-dragging or gravitomagnetism. It is known that
frame-dragging is an effect on spacetime, predicted by Albert Einstein’s
general theory of relativity, which would be used to generate artificial
gravitational fields similar to electric fields generated by
time-varying or moving magnetic fields with enhanced field strength
[25].
The space broom operated by a DHEM device is used for capturing the
space debris from the space environment [19]. An optical sorting
method will be used in the ISS for segregating the collected debris into
individual material and metal scraps. Using an electric channel
induction furnace, the separated metal scraps are converted into the
molten metal form. Further, a lucrative water atomization system
operated with a fuel cell has been adopted for converting the molten
metal into powder form, which produce the end products, viz., the metal
powder and the water. The segregated selected powders are utilized for
making solid propellant for chemical propulsion. The specially separated
silicon powders are used for building feigned soil for nurturingpharmaceutical flora in the ISS for the scarce drugdiscovery for the high-endurance health care management [3, 26-28].
An inclusive layout of the proposed methodology for space debris
mitigation and the energy conversion technique are described in the
subsequent section.