DARPA Daedalus VLEO program

[Asteroza]

DARPA is gearing up for a classified VLEO program

https://sam.gov/opp/c2661950818849bc8b226dbc632f3a0d/view


Likely proposers are Earth Observant and Blue Canyon, both of which are progressing in VLEO work.

https://eoi.space/
https://spacenews.com/blue-canyon-looks-to-demonstrate-small-satellite-performance-at-very-low-altitude/



VLEO area is starting to get interesting, as other groups are attempting it.


ESA is working on Skimsat with a number of partners
https://www.thalesgroup.com/en/worldwide/space/press-release/thales-alenia-space-and-qinetiq-pave-way-small-multimission

ESA is also studying air breathing electric propulsion (ABEP) to augment VLEO sats with no-refueling propulsion
https://csps.aerospace.org/papers/game-changer-breath-fresh-air-air-scooping-electric-propulsion-very-low-earth-orbit


Albedo thinks refuelable VLEO sats is a viable business case
https://albedo.com/


KAIST is considering a VLEO sat for demonstrating the technology as well
https://www.sedaily.com/NewsVIew/22TYOXE1GY

A commercial korean company is also chasing VLEO, using a compressed optics approach to reduce the cross sectional area (and thus drag) of a VLEO sat
https://skeyeon.com/

[leovinus]

Didn't we already have a thread for that titled "VLEO related research" ?
https://forum.nasaspaceflight.com/index.php?topic=56795.0

PS: Almost fun to see that what is old is new again. Very Low Earth Orbits (VLEO) were studied in the late 1950s by Dr. Krafft Ehricke in his awarded presentation titled "The Satelloid" at the IAF 6th International Astronautical Congress in Copenhagen. The term "Satelloid" was coined by him and seems relevant today again.

A satelloid designates a powered vehicle—half airplane, half spaceship—with sustained thrust that operates in circular orbits roughly between 100 to 200 kilometers where there is still a noticeable atmospheric drag. That region is too high for gliders and too low for satellites. The motion under power is the significant difference compared to a satellite.

Anyway, I'd love to see comparisons of the new concepts with the old Satelloids.

- “The Satelloid”, IAF 6th International Astronautical Congress, Copenhagen, 1–6 August 1955, published in Astronautica Acta, Vol. 2, No. 2, 1956, pp. 63–100 and Aero Digest, Vol. 73, pp 46-48,50,52,54, July 1956. It is image/page 598 under this link

[edzieba]

In addition to VLEO circular orbits, there are eccentric orbits that dip very low but otherwise spend most of their time out of the atmosphere. e.g. the GAMBIT satellites could down to 120km altitude for high resolution imaging runs. The GAMBITs had to reboost afterwards using the Agena's propulsion system, but an air-breathing capability might allow lower dips with longer orbit lifetimes.

[aceshigh]

Two questions:

1 - considering LASER advancements (for military applications) as well as laser propulsion research (like for Starshot interstellar missions), wouldn´t it be easier to have several laser stations, to push these VLEO satellites up (actually push forward so they regain speed). A country with a big territory will have the VLEO satellites crossing above the lasers every X orbits. In equatorial orbits, every 90 minutes (but then you would need to have these lasers installed in equatorial countries)

2 - this is probably the biggest nonsense you will read today in this forum but... considering all this talk about magnetic sail crafts soaring on the solar wind  (https://www.nextbigfuture.com/2022/12/extracting-energy-from-solar-winds-via-plasma-magnetic-sail-to-get-near-lightspeed.html) to % of light speed)...

But isn´t the Van Allen belt basically trapped solar wind particles?  And wouldnt VLEO satellites cross every few orbits the South Atlantic Magnetic Anomaly, where the Van Allen belt dips to a height of 200km above the surface?

In that case, wouldn´t it be possible for the satellites equipped with a much weaker magnetic sail get the required boost to compensate drag, by using magnetic sails in the Van Allen Belt when crossing the SAMA?

Sorry about the nonsense.