# The Orbital Index

Issue No. 115 | May 5, 2021

🚀 🌍 🛰
 ¶The passing of Michael Collins. Michael Collins, Command and Service Module (CSM) pilot for Apollo 11, has passed away at age 90. Michael remained in orbit as Neil Armstrong and Buzz Aldrin landed on the Moon. He is often cited (along with subsequent CSM pilots) as the loneliest man in history: as he orbited the lunar surface, he ventured as far as 3,585 km away from the next closest humans, on the other side of the Moon (although xkcd suggests that some Polynesian or Antarctic explorers may have matched this). Previously, as part of Gemini 10, Collins was the fourth human to conduct a spacewalk. After Apollo 11 and leaving NASA, Collins became director and oversaw the construction and opening of the Smithsonian National Air and Space Museum. He later took up painting, wrote Carrying the Fire, which is often considered to be the best astronaut autobiography, and always dreamed of Mars, which he spoke about in an interview with Smithsonian Magazine in 2019. NASA has a remembrance.
 Michael Collins took this photo as Neil Armstrong and Buzz Aldrin, ascending from the Moon, rejoined him in lunar orbit. The photo was re-processed by Toby Ord for his Earth Restored collection. Toby’s caption: Collins, who remained in orbit on the Command Module, is behind the lens. Every other human is in front of it.
 ¶Orbital Refueling. Late last week, NASA signed a final $25M contract for a first LEO fuel depot that will refuel the upper stages of smallsat launch vehicles. This depot demonstration mission, LOXSAT 1, is scheduled for launch in 2023 and will be followed by mission planning for a full-scale LOXSAT2 in 2025. The contract is the second related to cryogenic fuel management for Florida-based Eta Space—the company is also assisting with a$27M 2019 Tipping Point award for development of a fuel depot capable of operation on the lunar surface. Traditionally, on-orbit fuel depots have suffered from a difficult business case where third-party vehicles don’t invest in standardized support for on-orbit refueling due to the lack of existing depots in orbit—the last thing anyone wants is to develop and launch useless hardware. Northrop Grumman’s MEV-1 & 2 have sidestepped this issue by taking over all propulsion duties for large customer satellites, but the approach of having to dedicate a shepherd vehicle for each customer won’t scale for the smallsat market. This application of NASA funding, to overcome a chicken/egg problem, is some of the highest leverage dollars the agency can deploy. LOXSAT1 will include scaled-down versions of all systems required for operation and will launch on a Rocket Lab Electron (it will also be built on their Photon satellite bus). This contract announcement follows OrbitFab’s announcement in February that their Tanker-001 Tenzing satellite refueling platform will launch later this year on a Spaceflight-organized SpaceX rideshare. OrbitFab is solving the market entry problem by developing partnerships prior to launch. They’ve partnered with Benchmark Space Systems to resupply the company’s hydrogen peroxide thrusters using OrbitFab’s in-house developed RAFTI refueling interface—the refuelable thrusters are planned for use on Spaceflight’s forthcoming Sherpa space tug. SpaceX is also developing orbital refueling for Starship with NASA’s help on a massive scale—HLS Starship missions will require multiple refueling launches of Starship tankers (Casey Handmer estimates that refueling with 12 Starship tankers would allow an HLS Starship to transport 25 tons from LEO to the lunar surface and back). LOXSAT will supply LOX and RP-1, making its technology a fit for Rocket Lab, Astra, Virgin Orbit, and Firefly (but not ULA’s high-efficiency LH2 upper stages).