Two key technologies required to enable the exploration and exploitation of the solar system are space data communications systems and space vehicle propulsion. While the development of the core communication protocols (Delay & Disruption tolerant Networking (DTN)) is quite robust, deployment and planned adoption is essentially limited to space agency missions to earth orbit and the planned Lunar Gateway and LunaNet. NASA is committed to using DTN for manned missions to Mars, but other than some high-level architecture papers, there are no concrete plans for the development of the proposed Solar System Internet (SSI). That is somewhat understandable, given the natural conservatism of space agencies and the uncertainty of long-range planning when a changeable Congress holds the budget strings.
In fact, there are many reasons for optimism about the future of DTN:
The IETF DTN Working Group is slowly but surely cranking out DTN standards
CCSDS is concomitantly cranking out Blue Books (recommended standards for civilian space flight)
DTN is used for some comms on ISS
NASA is committed to DTN for Lunar Gateway and LunaNet (after some initial hesitancy—as recently as mid 2019 they were planning to use TCP/IP)
NASA/JPL continues to publish updates to ION (NASA’s implementation of the Bundle Protocols)
Commercialization of space is coming fast– YET… adoption is slow…
It’s mostly all about TCP/IP for now
The reason for this bullet can be explained by the graphic to the left: it’s all about where business investments are now and how those regions of space are affected by delay. The vast majority of even planned commercial use of space is concentrated within Low and Medium Earth Orbit (LEO & MEO) satellites—within the green circle. There is no significant delay here and current terrestrial communication protocols (like TCP/IP) work just fine. “If it ain’t broke, don’t fix it!”
The next major commercial thrust will be in cislunar space. That’s the region generally enclosed by the yellow ellipse in the graphic. Here, TCP/IP kinda sorta works, and given the NRCO orbit of the Lunar Gateway, which never loses LOS with Earth, NASA was originally tempted to use it. We wrote about this back in 2019, urging NASA to use DTN instead for a variety of reasons. Doubtless for reasons other than our blog posting, NASA decided to deploy DTN on Lunar Gateway and LunaNet. We assume that commercial entities involved in the initial business endeavors on the moon will therefore be using DTN.
The third region (depicted by the open-ended red ellipse in the graphic) is where the delay becomes so great that TCP definitely breaks. DTN will not be optional. But no one besides space agencies is doing anything out here. Yet.
The draw to exploit this region will be irresistible. “The first trillionaires will be those who mine in space”—Neal Degrasse Tyson. Forbes magazine, Bloomberg News and other pundits are predicting that commercialization of space—particularly Near Earth Asteroids (NEA’s) represents a huge business opportunity. Some go even further, saying that our ability to mine Technology-Critical Elements (TCE’s) from space is critical to the very survival of our increasingly technology-dependent civilization.
TCE’s are a group of about 35 elements (about 17 Rare Earth elements, 6 platinum group elements and another 12 “assorted” elements). They are critical to emerging technologies either because of their rarity (as in “Rare Earth Elements”) a striking increase in demand, or both. An example would be tantalum, which is required for the manufacture of capacitors and resistors contained in most electronic devices. A small number of asteroids are expected to be significant sources of these rare (on earth) elements particularly the platinum group elements. Their high value-to-mass ratio may make it worthwhile to transport them back to earth.
DTN is an established technology waiting for adoption by the emerging space industries (and buildout of required infrastructure). There is another arena where development is needed in order to support the opportunities for expanded exploration and exploitation of space: improved propulsion systems for space vehicles. There have been drastic improvements in the cost per pound of boosting satellites into orbit. That has been coupled with the miniaturization of satellites themselves to make Cube Sats available to small businesses and graduate students alike.
But conventional rockets are still really inefficient in terms of the amount of fuel required to put payload into orbit. This is typically expressed in terms of Payload Fraction (what percentage of the entire spacecraft launch weight does the payload represent?). While some newer platforms represent substantial improvements, most haven’t improved much since the days of the Apollo missions. Case in point: the Payload Fraction for the Space-X Starship (4.3%) is only slightly better than the Saturn V (5.3%) to boost payload into Earth orbit.
However, the Payload Fraction for the Saturn V dropped to less than 1.5% when boosting to escape velocity. As the photo at left shows, even the most powerful rockets are metal tubes of mostly fuel…
There are a number of small companies involved in potentially game-changing development work on technologies like Nuclear Thermal Rockets, solar wind sails and others that can vastly improve Payload Fraction, reduce fuel costs as well as reduce travel times to Jupiter and beyond. There is an excellent webinar produced by Space Matters available on YouTube with representatives from a number of these companies discussing the technologies involved as well as the challenges to overcome. It is available for viewing at: https://www.youtube.com/watch?v=th4ISGnhcLs. They are a relatively new YouTube Channel, but seem to be producing several videos a month.
They also have a profile of astronaut Story Musgrave and another webinar on space policy.
Check them out!
