{"id":86391,"date":"2025-09-26T08:31:11","date_gmt":"2025-09-26T08:31:11","guid":{"rendered":"https:\/\/www.europesays.com\/ie\/86391\/"},"modified":"2025-09-26T08:31:11","modified_gmt":"2025-09-26T08:31:11","slug":"what-is-on-orbit-refueling-inside-the-technology-that-could-solve-orbital-debris","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/ie\/86391\/","title":{"rendered":"What is on-orbit refueling? Inside the technology that could solve orbital debris"},"content":{"rendered":"

Today, multiple space agencies are preparing to send crewed missions back to the Moon for the first time since the Apollo Era<\/a>. Meanwhile, the commercial space industry is booming, with a growing number of launch providers deploying constellations of satellites to orbit. All these developments show that we live in an era of renewed space exploration: NewSpace, or Space 2.0<\/a>.<\/p>\n

Much of this is due to rocket retrieval and reusability development, which has led to a significant drop in the cost of sending payloads to space.<\/p>\n

Another way to reduce costs is with On-Orbit Refueling<\/a> (OOR), also known as in-space propellant transfer. NASA has researched this concept for decades to facilitate missions to the Moon and beyond. If companies like SpaceX get their way, Low Earth Orbit (LEO) could someday be filled with refueling depots, enabling commercial trips to the Moon and possibly Mars.<\/p>\n

However, OOR could also enable other kinds of operations in LEO while addressing a major environmental issue: the growing problem of space junk<\/a>. By providing satellite refueling services in orbit, government agencies, and telecommunications and commercial space companies, can indefinitely extend the life of satellites. This will prevent them from becoming defunct once they run out of fuel and add to the burgeoning environmental crisis in space.<\/p>\n

To this end, Amazon and commercial space startup Arkisys<\/a> recently announced they were teaming up to develop satellite refueling capabilities using Arkisys\u2019 proposed commercial space platforms, known as \u201cThe Port<\/a>.\u201d These in-orbit facilities will enable the assembly, integration, and resupply of satellites in orbit, which satellite providers will likely rely on to service their constellations.<\/p>\n

Orbital debris<\/p>\n

According to the most recent numbers released by the Space Debris Office<\/a> at the European Space Operations Center<\/a> (ESOC), about 6960 launches have occurred since Sputnik 1 was launched into space, excluding failed launches. These launches have placed countless payloads into orbit, including about 22,310 satellites. In the past 60 years, it is estimated that more than 650 break-ups, explosions, or collisions have taken place between inoperable satellites, spent rocket stages, and other defunct payloads.<\/p>\n

Over time, this has led to the current situation in Low Earth Orbit (LEO), which is littered with space debris. These objects pose a significant threat to operational satellites, spacecraft, and space stations. To make matters worse, collisions between defunct satellites, spent stages, and other payloads launched into space create additional debris, which could lead to what is known as the Kessler Effect<\/a> (or collisional cascading). This phenomenon is named for NASA astrophysicist Donald J. Kessler<\/a>, who proposed it in a paper published in 1978.<\/p>\n

In this scenario, the density of objects in Low Earth Orbit (LEO) becomes high enough that collisions between objects would cause a cascade effect. As objects collide, they produce smaller objects that collide with others. With every collision, more space debris is generated, and the likelihood of further collisions increases exponentially. While space agencies and commercial partners are pursuing mitigation and debris removal strategies, the single greatest factor is the nature of satellites.<\/p>\n

At present, satellites are an example of single-use technology, deployed once and then discarded once they run out of fuel. <\/p>\n

\u201cSatellite refueling is the only way to extend the lives of satellites, which usually live around 4-8 years (or some 15 years for GEO). This means that, for every satellite in space, after the clock reaches that point, they become space debris that can crash against any operating satellite, creating an explosion with hundreds or even thousands of parts. In other words, satellite refueling is a way to not only extend our permanence in Earth orbit, but to avoid us being confined to our own planet indefinitely,\u201d Rodrigo Schmitt, PhD Candidate in Aeronautics & Astronautics at\u00a0Purdue University and a researcher with the Center for Integrated Systems in Aerospace<\/a>, told Interesting Engineering via email.<\/p>\n

On-orbit refueling<\/p>\n

NASA originally explored the idea of OOR during the 1960s, eventually leading to the Integrated Program Plan (IPP)\u2014aka Space Transportation System (STS)\u2014in 1969. This plan envisioned a series of reusable crewed space vehicles supporting extended operations beyond the Apollo program<\/a>, allowing for missions between Earth and the Moon and the first human missions to Mars.<\/p>\n

The mission architecture included orbital propellant depots stationed in LEO and lunar orbit to reduce the propellant (and therefore mass) the spacecraft would need to carry to space. This plan was eventually passed over in favor of the Space Shuttle Program<\/a>, and the term STS was used to refer to the orbital shuttle vehicle \u2013 the only part of the IPP to be realized.<\/p>\n

Nevertheless, NASA and the U.S. Department of Defense (DOD) conducted numerous space-serving studies during the 1980s. This led to a systems engineering and integration study by the early 1990s, conducted by NASA\u2019s Johnson Space Center New Initiatives Office in collaboration with Hernandez Engineering, Inc.<\/a> (HEI). These studies showed that on-orbit refueling was feasible, but a flight demonstration was still needed.<\/p>\n

\"\"Illustration of NASA\u2019s proposed Integrated Program Plan. Credit: NASA<\/p>\n

The concept was explored extensively since the turn of the century. This included an experimental on-orbit demonstration<\/a> by the USAF and United Launch Alliance in 2009 (ULA) using a modified Centaur upper stage<\/a>. During the flight, six demonstrations were performed involving the transfer of 12,000 lbs (5,400 kg) of liquid oxygen (LOX) and liquid hydrogen (H2) propellant. In 2010, NASA\u2019s Future In-Space Operations<\/a> (FISO) Working Group held a meeting to discuss a single-vehicle propellant depot concept for cislunar transportation.<\/p>\n

In 2011, NASA contracted with four aerospace companies<\/a> to \u201cdefine demonstration missions that would validate the concept of storing cryogenic propellants in space to reduce the need for large launch vehicles for deep-space exploration.\u201d Per the contract, Analytical Mechanics Associates, Boeing, Lockheed Martin, and Ball Aerospace received $600,000 to develop technologies for storing and transferring cryogenic propellants and concepts for cryogenic depots.<\/p>\n

In April 2021, NASA selected SpaceX to develop a Human Landing System<\/a> (HLS) for the Artemis Program. The mission architecture included OOR, consisting of multiple tanker vehicles launched to service a refueling depot in LEO. During the Starship\u2019s third integrated flight<\/a>, intravehicular propellant transfer in orbit was demonstrated. An intervehicular propellant transfer demonstration mission<\/a> was originally planned for 2025, but has since slipped to 2026.<\/p>\n

Megaconstellations are coming<\/p>\n

In the coming years, multiple companies plan to deploy satellite \u201cmegaconstellations\u201d to provide broadband internet access. SpaceX\u2019s subsidiary Starlink<\/a> currently dominates this market, with over 7,600 satellites in orbit (as of May 2025), providing coverage to around 130 countries and territories. But with companies like Blue Origin\u2019s subsidiary Project Kuiper, China\u2019s Spacesail<\/a>, and others entering the market, Earth orbit is projected to become fully \u201ccommercialized\u201d in the coming years.<\/p>\n

So far, China\u2019s Spacesail has deployed about 90 planned 14,000 satellites for its Qianfan (\u201cthousand sails\u201d in Chinese) constellation since August 2024. In March, the company signed a Memorandum of Understanding<\/a> (MoU) with Brazil\u2019s state-owned telecommunications company, Telecomunicacoes Brasileiras (Telebras), to explore the demand for satellite internet in areas where fiber optic infrastructure is unavailable.<\/p>\n

Meanwhile, Project Kuiper\u2019s deployment is planned in five phases, and internet service will begin once the first 578 satellites are launched. According to its FCC license<\/a>, granted in 2023, Amazon must launch and operate half its satellites by July 30th, 2026, followed by the other half by July 30, 2029.<\/p>\n

In April 2023<\/a>, Amazon secured launch contracts with United Launch Alliance, Arianespace, and Blue Origin (owned by Amazon founder Jeff Bezos) to launch satellites using their Vulcan, Ariane 6, and New Glenn rockets (respectively). This was followed by Amazon signing a contract with rival SpaceX in December 2023<\/a> to launch three payloads of its satellites using their Falcon 9 rocket.<\/p>\n

In April 2025, the Kuiper Atlas-1 (KA-1) mission deployed the first 27 satellites<\/a> of Project Kuiper into space using the ULA\u2019s Atlas 5 rocket. This was followed by KA-2 and KA-3<\/a> on June 23 and July 16, which sent 24 and 27 satellites to orbit (respectively). The most recent launch, KA-4, sent an additional 24 to space on August 11, 2025<\/a>, growing the constellation to 100 satellites.<\/p>\n

This will lead to a rather crowded environment in Earth orbit. Arkisys CEO Dave Barnhart told IE via email that \u201clow earth orbit (LEO) constellations have been enabled by advances in technology and reduction in both launch and the satellite costs.\u201d <\/p>\n

\u201cAs such it is now possible to provide 24\/7 coverage over any area on earth through multiple small satellites orbiting in a \u201cstring of pearls\u201d instead of very large and expensive satellites way out at the geostationary belt. While opening up reduction in costs for ground customers, it also is presenting an interesting dilemma in space that was not anticipated 50 years ago when the space industry started; namely very crowded orbits!\u201d<\/p>\n

To this end, Arkisys recently teamed up with Orbit Fab<\/a>, a commercial space company dedicated to eliminating single-use spacecraft with in-space refueling. This collaboration could pave the way for other OOR services, ushering in a new era of post-launch space servicing. This would drastically extend the service lives of satellites while reducing the amount of defunct satellites (as well as the resulting space junk caused by collisions) in orbit.<\/p>\n

The coming age of space exploration, with plans to commercialize LEO and achieve long-duration missions to the Moon, Mars, and beyond, requires achieving sustainability in space. Ensuring that the spacecraft launched to orbit and beyond are multi-use in nature.<\/p>\n

Stay tuned for Part II to learn more about this exciting program.<\/p>\n","protected":false},"excerpt":{"rendered":"Today, multiple space agencies are preparing to send crewed missions back to the Moon for the first time…\n","protected":false},"author":2,"featured_media":86392,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[270],"tags":[8131,18,19,2928,17,452,133,451],"class_list":{"0":"post-86391","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-space","8":"tag-aerospace","9":"tag-eire","10":"tag-ie","11":"tag-inventions-and-machines","12":"tag-ireland","13":"tag-physics","14":"tag-science","15":"tag-space"},"share_on_mastodon":{"url":"","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/86391","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/comments?post=86391"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/86391\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media\/86392"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media?parent=86391"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/categories?post=86391"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/tags?post=86391"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}