X-37B Orbital Test Vehicle (OTV)

Article as regards the X-37B & its service module:

www.thedrive.com

Look At An X-37B In Space With An Extended Payload Module

Space Force's secretive X-37B just launched on its seventh mission, which will be its most ambitious, aboard a SpaceX Falcon 9 Heavy rocket.
www.thedrive.com www.thedrive.com

Some footage of the combination in space from the previous flight was mixed into the coverage of this flight.
 
I’ve seen it suggested that the X-37 maybe in a Molyniya type orbit which would be hard for amateur observers to track.
 
Flyaway said:
I’ve seen it suggested that the X-37 maybe in a Molyniya type orbit which would be hard for amateur observers to track.
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And yet someone found it. It does appear to be in a highly elliptical orbit inclined about 59 degrees. Not sure if it's technically a molniya or not, but it's in the ballpark.

arstechnica.com

A sleuthing enthusiast says he found the US military’s X-37B spaceplane

Officials didn't disclose details about the X-37B's orbit after its December launch.
arstechnica.com arstechnica.com
 
Flyaway said:
a Molyniya type orbit
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Had to go look that up, even with as much as I like space stuff it was a thing I did not know.

The Molniya orbit combines high inclination (63.4°) with high eccentricity (0.722) to maximize viewing time over high latitudes. Each orbit lasts 12 hours, so the slow, high-altitude portion of the orbit repeats over the same location every day and night. Russian communications satellites and the Sirius radio satellites currently use this type of orbit. (Adapted from Fundamentals of Space Systems by Vincent L. Pisacane, 2005.)
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Catalog of Earth Satellite Orbits

Different orbits give satellites different vantage points for viewing Earth. This fact sheet describes the common Earth satellite orbits and some of the challenges of maintaining them.
earthobservatory.nasa.gov earthobservatory.nasa.gov
 
The hunt for OTV-7:

skyriddles.wordpress.com

The Hunt for OTV-7

On a dark late December winter night the United States military launched its secretive X-37B spaceplane atop a Falcon 9 heavy rocket from Kennedy Space Center. After watching the rocket slip from s…
skyriddles.wordpress.com skyriddles.wordpress.com
 
So the X-37B is in Molniya orbit ? what it does here is anybody guess. I would hazard that Molniya orbit are a soviet / russian thing. Which brings THE question:
What kind of assets do the russians have in Molniya orbit that would be worth the X-37B "interacting" with them ?

en.wikipedia.org

Molniya (satellite) - Wikipedia

en.wikipedia.org en.wikipedia.org

By the way the Soviets have satellites spying the GEO belt comsats: so maybe the X-37B is doing something similar with russian comsats, which have often been in Molniya orbit for geographical reasons (makes more sense for Russia being a giant country north of the equator)
 
I think that the ellipsoidal orbit is more about maneuvering in the fast portion of it.
You need that kind of of trajectory to get low enough to use aerodynamics effects.
The slow portion give more time for Hall thrusters to alter the trajectory.
In effect, the heterogeneous characteristics of the X-37 are maximized that way.
 
TomcatViP said:
I think that the ellipsoidal orbit is more about maneuvering in the fast portion of it.
You need that kind of of trajectory to get low enough to use aerodynamics effects.
The slow portion give more time for Hall thrusters to alter the trajectory.
In effect, the heterogeneous characteristics of the X-37 are maximized that way.
Click to expand...
Not really. What Hall thrusters? That was just a test on a previous mission. Also, they would be too weak for setting up and ending dip into the atmosphere.

Anyways, the X-37 needs to have its payload bay open and its solar array deployed. These are not meant for repeat operations on orbit. it can only operate for a limited time with payload bay closed.
 
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Archibald said:
So the X-37B is in Molniya orbit ? what it does here is anybody guess. I would hazard that Molniya orbit are a soviet / russian thing. Which brings THE question:
What kind of assets do the russians have in Molniya orbit that would be worth the X-37B "interacting" with them ?

en.wikipedia.org

Molniya (satellite) - Wikipedia

en.wikipedia.org en.wikipedia.org

By the way the Soviets have satellites spying the GEO belt comsats: so maybe the X-37B is doing something similar with russian comsats, which have often been in Molniya orbit for geographical reasons (makes more sense for Russia being a giant country north of the equator)
Click to expand...
The US uses Molniya orbit too. There is no equivlent to the GEO belt for Molniya

The orbits are too diverse to follow unless launched specifically in the same orbit as the "single" satellite that is to be monitored.
 
Byeman said:
Not really. What Hall thrusters? That was just a test on a previous mission. Also, they would be too weak for setting up and ending dip into the atmosphere.

Anyways, the X-37 needs to have its payload bay open and its solar array deployed. These are not meant for repeat operations on orbit. it can only operate for a limited time with payload bay closed.
Click to expand...
Nobody mentioned firing the thruster in the atmosphere but during coast-up and down leg from the apogee.
 
Archibald said:
So the X-37B is in Molniya orbit ?
Click to expand...

I see people arguing that it's not a Molniya because it isn't frozen; it processes slowly over the surface, which the true Molniya doesn't. I think. This is beyond my full comprehension but sharing for others.


Edit: this link should point to a comment by theradicalmoderate on the first page of comments.

arstechnica.com

A sleuthing enthusiast says he found the US military’s X-37B spaceplane

Officials didn't disclose details about the X-37B's orbit after its December launch.
arstechnica.com arstechnica.com
 
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I think a true Molniya orbit maintains an apogee over a specific geographic location. It was first used by communications satellites of the same name IIRC, with three satellites in the same orbit, with one on station in the high end of orbit. The Russians based the orbit over their country for relay. The U.S. uses the same orbit for ELINT satellites over Asia (TRUMPET series).
 
TomcatViP said:
Nobody mentioned firing the thruster in the atmosphere but during coast-up and down leg from the apogee.
Click to expand...
Neither did I. To dip in the atmosphere at perigee requires a delta V at apogee, not during the "legs" before and after. A Hall thruster is too weak for this.
 
We are not requiring a Voodoo like 50ft fly by ;)

The delta E gained extending the leg up and increasing the speed down (yes, elevating the Apogee) can be traded for skiming the high layer of the atmosphere and use the delta V to change the orbit.

That's it. I am not suggesting any amplitude here. It's only basic physics

Voodoo-Cuba-960_640.jpg

Not that yet(?!)
 
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TomcatViP said:
We are not requiring a Voddoo like 50ft fly by ;)

The delta E gained extending the leg up and increasing the speed down (yes, elevating the Apogee) can be traded for skiming the high layer of the atmosphere and use the delta V to change the orbit.

That's it. I am not suggesting any amplitude here. It's only basic physics
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wrong, that is not how orbital mechanics work. Delta V affects an orbit at point 180 degrees from the point of application. To raise and lower the orbit into the atmosphere at perigee requires the delta V be applied at apogee. Once the orbit is lowered into the atmosphere, braking will occur and the apogee will be lowered.
 
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Question: does the X-37 have enough fuel to recover from a GTO? I would think a huge amount of breaking would be necessary to slow to a survivable re-entry speed. Is the vehicle counting on atmospheric drag at perigee over time to allow it to recover? Is it possibly being expended?
 
Josh_TN said:
Question: does the X-37 have enough fuel to recover from a GTO? I would think a huge amount of breaking would be necessary to slow to a survivable re-entry speed. Is the vehicle counting on atmospheric drag at perigee over time to allow it to recover? Is it possibly being expended?
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Discussed here:

sattrackcam.blogspot.com

Imaging the X-37B robotic spaceplane mission OTV 7

classified military Space (spy satellites) and Missiles
sattrackcam.blogspot.com sattrackcam.blogspot.com

tl;dr Orbit will be circularized to LEO first, possibly by aerobraking at perigee
 

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