ULEO/VLEO related research

[Asteroza]

ESA and Thales are getting together to work on a VLEO earth observation design called Skimsat.

https://www.thalesgroup.com/en/worldwide/space/press-release/thales-alenia-space-and-qinetiq-pave-way-small-multimission

https://arxiv.org/abs/2108.01945

Notable is that the pictured Skimsat does not appear to use air breathing electric propulsion (ABEP), which also is recently being pursued by ESA.

https://www.esa.int/Enabling_Support/Space_Engineering_Technology/World-first_firing_of_air-breathing_electric_thruster

Though there were past efforts by JAXA and NASA on ABEP designs.


VLEO (less than 250km orbit) is an interesting niche, particularly for earth observation and remote sensing missions as well as low latency satellite communications, along with the potential to source gas propellants outside the gravity well (nitrogen and oxygen) via air scooping. Though the high air drag regime means either lots of propellant, high power electric thrusters (still propellant limited), or the holy grail of ABEP (which effectively allows a VLEO sat to become a forever flyer). ABEP will be difficult though, because you are running on the high end of hypersonic range, needing weird inlets, and the variable nature of the earth's atmosphere makes navigation tricky.

Past design concepts in the VLEO design space include the PROFAC nuclear powered arcjet air scooping propellant tanker (and more modern solar takes like PHARO and CHARON using solar electric propulsion), and some actual electric thruster reboost demos such as ESA's GOCE and JAXA's SLATS (neither of which featured an ABEP thruster). Some atmosphere miner concepts are single body with a big funnel out front, but others feature a ramscoop hung on a tether from a power/tankage body (trawling the atmosphere like a fish trawler) and potentially using the tether itself for electrodynamic reboost.


There's seems to be a proposed korean VLEO design from KAIST, which uses a big 45 degree mirror in the body to allow downward imaging while flying forward.

Some sort of VLEO EO sat in development, via SatRec Initiative? Sorta similar to SLATS and GOCE.

https://www.sedaily.com/NewsVIew/22TYOXE1GY
https://www.satreci.com/korean/sub0401

There's also some commercial startups working on VLEO.

There was a US military AFWERX contract in 2020 for Earth Observant, who are using a shuttlecock style design
https://www.earthobservant.com/
https://eoi.space/
https://www.forbes.com/sites/erictegler/2020/08/28/how-low-can-satellites-go-air-force-bets-very-low-earth-orbit-will-give-it-more-capabilities/?sh=5eecdbe81da3

along with Skeyeon, who are using a novel compressed telescope design using concentric folded optics to allow a flatter sat bus body while still being downward shooting
https://skeyeon.com/
who appear to be be currently working on atomic oxygen erosion issues on ISS via materials tests, and while their current sat concept does not appear to have ABEP, they do have an ABEP patent which shows an interesting sat bus design. Considering the thin design of Skimsat, it too may have a similar compressed telescope design (or is hosting some sort of planar SAR phased array sensor on the belly)

another startup is Albedo, who seem to pushing VLEO to allow 10cm GSD imaging
https://albedo.com/
who seem to not be using a shuttlecock or otherwise aerodynamic design (a fairly conventional hexagonal telescope body sat bus), and don't appear to be using ABEP. Allegedly they are dependent on propellant refueling for reboost, but provided by whom?

[Asteroza]

Indian newspace startup Bellatrix Aerospace is working on something called Project 200, which appears to be a VLEO sat using something similar to a hall effect thruster that might be air breathing, based on the multiyear sat lifetime comment and the engine being called Arka Air.

https://www.thehindu.com/sci-tech/science/bengaluru-start-up-unveils-satellite-to-operate-at-an-ultra-low-earth-orbit/article68655587.ece
https://bellatrix.aero/project200

They appear to have some hall effect thruster development experience.



With Redwire/Made in Space researching 2 different ABEP satellite buses, VLEO is getting hotter.

[Asteroza]

UK startup touting ABEP VLEO, and calling 180km orbits ULEO

https://www.neworbit.space/

[sanman]

Indian newspace startup Bellatrix Aerospace is working on something called Project 200, which appears to be a VLEO sat using something similar to a hall effect thruster that might be air breathing, based on the multiyear sat lifetime comment and the engine being called Arka Air.

https://www.thehindu.com/sci-tech/science/bengaluru-start-up-unveils-satellite-to-operate-at-an-ultra-low-earth-orbit/article68655587.ece
https://bellatrix.aero/project200

They appear to have some hall effect thruster development experience.



With Redwire/Made in Space researching 2 different ABEP satellite buses, VLEO is getting hotter.

Here's a further article on Bellatrix:

https://spectrum.ieee.org/low-earth-orbit-satellite-india

[sanman]

Can anyone tell me - what are the possibilities of using VLEO/ULEO satellites equipped with Air-Breathing Electric Propulsion as future planetary probes? Would it be useful for a probe to be flying VLEO/ULEO like that around Mars or Venus, or some other atmospheric body in our Solar System?

Are the molecular/ionic species sufficiently similar for the upper atmospheres of Mars or Venus in comparison to Earth that the same technology could be used? Or would the difference in atmospheric compositions require radical redesign?