LEO inclination changes can be done at any point in the orbit. It is only for GTO elliptical orbits where you really have to do it over the equator, otherwise your apogee is not going to be over the equator.
Quote from: Lars-J on 09/23/2017 10:56 pmLEO inclination changes can be done at any point in the orbit. It is only for GTO elliptical orbits where you really have to do it over the equator, otherwise your apogee is not going to be over the equator.Again using launch from the Cape to equatorial LEO as an example (28° plane change requirement), by changing 28° at an orbital node (over the equator), an equatorial orbit is achieved directly (diagram 1). This is what I modelled for Comga.If the burn was instead performed at maximum declination (28° latitude), the orbital plane would have been tipped sideways by 28° (diagram 2). The resultant orbit would have an inclination of 38°. If I had been trying to achieve equatorial orbit, any burn at maximum declination would have increased inclination, and been counter-productive. If I had been trying to increase inclination, then I would have obtained only a 10° change in declination for a 28° plane change.Lastly, if I had been trying to increase inclination, and the burn had been performed at the equator, the resultant orbit would have a 56° inclination, nearly 3 x better (diagram 3). In short, yes you can change plane at any point in a low earth orbit, but changing plane is not the same as changing inclination, unless you do so at the equator.
I'm not sure why X-37B would go to an equatorial orbit;
However, every non-SSO orbit intersects every SSO plane once per orbit: as long as you launch at the right time of day, you don't have to wait to cross the equator to burn into a specified SSO.
Could OTV-5 have been spotted, if it has its much fainter than expected.http://www.satobs.org/seesat/Sep-2017/0115.html
Quote from: envy887 on 09/25/2017 12:55 pmI'm not sure why X-37B would go to an equatorial orbit;I'm not suggesting it would, I was just trying to show why it is advantageous to perform plane change at the equator.
Quote from: OneSpeed on 09/25/2017 01:33 pmQuote from: envy887 on 09/25/2017 12:55 pmI'm not sure why X-37B would go to an equatorial orbit;I'm not suggesting it would, I was just trying to show why it is advantageous to perform plane change at the equator.It is not advantageous to perform plane change at the equator.it is very unadvantageous to perform plane change at the equator, but it is necessary when the target inclination is zero.
Quote from: Star One on 09/24/2017 06:04 pmCould OTV-5 have been spotted, if it has its much fainter than expected.http://www.satobs.org/seesat/Sep-2017/0115.htmlTed Molczan's followup gives some search TLE's but cautions it could also fit TecSar (08002A / 32476) which was last observed in the spring of 2016. http://www.satobs.org/seesat/Sep-2017/0118.html So, if it is OTV-5 and it is fainter than expected, could this indicate a deployable test of optical stealth technology. Something along the lines of Teledyne's famous patent? https://www.google.com/patents/US5345238
Here’s a further follow up on the matter.http://www.satobs.org/seesat/Sep-2017/0120.htmlhttp://www.satobs.org/seesat/Sep-2017/0121.htmlAnd this.http://www.satobs.org/seesat/Sep-2017/0123.html
Quote from: Star One on 09/25/2017 05:01 pmHere’s a further follow up on the matter.http://www.satobs.org/seesat/Sep-2017/0120.htmlhttp://www.satobs.org/seesat/Sep-2017/0121.htmlAnd this.http://www.satobs.org/seesat/Sep-2017/0123.htmlAs the thread progresses, it seems they are more and more convinced the sighting is TecSar and not OTV-5.
For the specific case of going from a circular 28 degree LEO to a circular SSO at same altitude, this is incorrect.It may help to visualize the various planes, but it comes down to this: the angle between a 28 degree orbit and SSO is greatest at highest latitude. When crossing the equator, there is a velocity component in the direction of the SSO, while at highest latitude the orbits are very nearly perpendicular.However, is is still FAR cheaper to do the change while suborbital instead of waiting to cross the equator.
Quote from: hkultala on 09/21/2017 05:24 pmQuote from: macpacheco on 09/21/2017 05:03 pmMy money is on the 2nd stage substantially changed the target inclination from the booster trajectory.And X-37B has radar absorbing material, making it nearly impossible to detect it (helped by the sheer distance from the ground it flies at).Its a secret space plane for a reason.An basis for the claims about the radar-absorbing materials?No reliable source seems to claim so.Any reliable sources would be under threat of jail time if they said anything. Stealth is nothing new. Not putting some stealth on a space plane would be incompetence in my view.
Quote from: macpacheco on 09/21/2017 05:03 pmMy money is on the 2nd stage substantially changed the target inclination from the booster trajectory.And X-37B has radar absorbing material, making it nearly impossible to detect it (helped by the sheer distance from the ground it flies at).Its a secret space plane for a reason.An basis for the claims about the radar-absorbing materials?No reliable source seems to claim so.
My money is on the 2nd stage substantially changed the target inclination from the booster trajectory.And X-37B has radar absorbing material, making it nearly impossible to detect it (helped by the sheer distance from the ground it flies at).Its a secret space plane for a reason.
Quote from: Prettz on 09/21/2017 07:36 pmSo do you think the stealth coating is overtop or under the various thermal protection materials?Perhaps on top, and burns up during re-entry and reapplied before each mission.X-37B has a pretty cozy ride up, only gets cooked on the way down.Pure speculation of course. But would make sense.
So do you think the stealth coating is overtop or under the various thermal protection materials?
Inclination change is relatively cheap when it's done early enough (immediately after staging of rocket with low-impulse 1st stage). It's very expensive when it's done late
In short, yes you can change plane at any point in a low earth orbit, but changing plane is not the same as changing inclination, unless you do so at the equator.
Quote from: OneSpeed on 09/25/2017 12:34 pm In short, yes you can change plane at any point in a low earth orbit, but changing plane is not the same as changing inclination, unless you do so at the equator.WrongWhat is meant by a dog leg. It is during ascent before the vehicle is orbital. The vehicle flies out at a certain azimuth and then steers to another one which changes the inclination. The only limitation (other than propellant) is that the vehicle can not go to a lower inclination than the latitude it is at during the maneuver. Also, inclination change does not have to be at the equator. That is just the most efficient place for the maneuver,. other locations are not as efficient and are subject to the above limitation.
Quote from: macpacheco on 09/21/2017 07:46 pmQuote from: Prettz on 09/21/2017 07:36 pmSo do you think the stealth coating is overtop or under the various thermal protection materials?Perhaps on top, and burns up during re-entry and reapplied before each mission.X-37B has a pretty cozy ride up, only gets cooked on the way down.Pure speculation of course. But would make sense.No, it makes no sense. There is no such thing as a spray on stealth coating
Quote from: Jim on 09/25/2017 08:15 pmQuote from: macpacheco on 09/21/2017 07:46 pmQuote from: Prettz on 09/21/2017 07:36 pmSo do you think the stealth coating is overtop or under the various thermal protection materials?Perhaps on top, and burns up during re-entry and reapplied before each mission.X-37B has a pretty cozy ride up, only gets cooked on the way down.Pure speculation of course. But would make sense.No, it makes no sense. There is no such thing as a spray on stealth coatingF-35 paint is classified, guess why.http://www.businessinsider.com/where-f-35-gets-classified-features-2015-5
Quote from: meberbs on 09/25/2017 08:51 pmQuote from: Jim on 09/25/2017 08:15 pmQuote from: macpacheco on 09/21/2017 07:46 pmQuote from: Prettz on 09/21/2017 07:36 pmSo do you think the stealth coating is overtop or under the various thermal protection materials?Perhaps on top, and burns up during re-entry and reapplied before each mission.X-37B has a pretty cozy ride up, only gets cooked on the way down.Pure speculation of course. But would make sense.No, it makes no sense. There is no such thing as a spray on stealth coatingF-35 paint is classified, guess why.http://www.businessinsider.com/where-f-35-gets-classified-features-2015-5Because it absorbs radar. Of course, we aren't talking about radar observations here, but optical.