-
#20
by
Lars_J
on 24 Jan, 2013 17:28
-
This may be a stupid question, but when using solid upper/kick stages - I assume that they use some kind of thrust-termination to make sure that the payload is delivered in the proper orbit?
Or is that up to the payload itself to fine-tune?
-
#21
by
Jim
on 24 Jan, 2013 17:39
-
This may be a stupid question, but when using solid upper/kick stages - I assume that they use some kind of thrust-termination to make sure that the payload is delivered in the proper orbit?
Or is that up to the payload itself to fine-tune?
There are three ways.
a. There is always some fine tuning by the payload
b. There is ballasting
c. adaptive flight control, where the vehicle dissipates excess energy with a less efficient trajectory.
-
#22
by
edkyle99
on 24 Jan, 2013 19:47
-
This may be a stupid question, but when using solid upper/kick stages - I assume that they use some kind of thrust-termination to make sure that the payload is delivered in the proper orbit?
Or is that up to the payload itself to fine-tune?
There are three ways.
a. There is always some fine tuning by the payload
b. There is ballasting
c. adaptive flight control, where the vehicle dissipates excess energy with a less efficient trajectory.
There is a possibility, too, that the integration of the upper solid motor into the Guidance and Control Assembly (GCA) provides a means of trimming velocity a bit. The GCA, which is a doughnut shaped structure around the smaller solid motor, has a cold gas attitude control system to position the stage during coast periods and to provide roll control during burns. I'm not sure if it is also used to trim insertion velocity, but it seems possible, though to a limited extent. (The Users Guide only discusses "energy management", by which it means (c) above, achieved by varying the orientation and start time of the final stage burn after a coast period.)
I'm guesstimating that Minotaur 6 might be able to lift 3.2 tonnes or more to LEO from Cape Canaveral. Minotaur 6+ might lift 3.4 or more tonnes.
- Ed Kyle
P.S. - It's good to see the old "PAM-D" (of a sort) still in action.
-
#23
by
Kabloona
on 26 Jan, 2013 05:49
-
This may be a stupid question, but when using solid upper/kick stages - I assume that they use some kind of thrust-termination to make sure that the payload is delivered in the proper orbit?
Or is that up to the payload itself to fine-tune?
There are three ways.
a. There is always some fine tuning by the payload
b. There is ballasting
c. adaptive flight control, where the vehicle dissipates excess energy with a less efficient trajectory.
One more way is possible. Some solid upper stages are designed so that, after manufacture, the propellant grain can be precision-machined to remove propellant to tailor the total impulse delivered to the payload. The Orbus 21 used by IUS and TOS was designed that way. It carried a nominal load of 21,000 lbs propellant +/-, but could be "offloaded" by up to 50% by machining the grain from inside out, like coring an apple from the center out, after the grain was cast. That way an off-the-shelf motor could be tailored to a specific payload without resorting to ballast.
Of course, even with a precisely tailored propellant load you do get some impulse variability that has to be trimmed out in the ways Jim and Ed have mentioned.
-
#24
by
Jim
on 26 Jan, 2013 12:58
-
This may be a stupid question, but when using solid upper/kick stages - I assume that they use some kind of thrust-termination to make sure that the payload is delivered in the proper orbit?
Or is that up to the payload itself to fine-tune?
There are three ways.
a. There is always some fine tuning by the payload
b. There is ballasting
c. adaptive flight control, where the vehicle dissipates excess energy with a less efficient trajectory.
One more way is possible. Some solid upper stages are designed so that, after manufacture, the propellant grain can be precision-machined to remove propellant to tailor the total impulse delivered to the payload. The Orbus 21 used by IUS and TOS was designed that way. It carried a nominal load of 21,000 lbs propellant +/-, but could be "offloaded" by up to 50% by machining the grain from inside out, like coring an apple from the center out, after the grain was cast. That way an off-the-shelf motor could be tailored to a specific payload without resorting to ballast.
Of course, even with a precisely tailored propellant load you do get some impulse variability that has to be trimmed out in the ways Jim and Ed have mentioned.
-
#25
by
Lars_J
on 27 Jan, 2013 03:42
-
My question was more related with how all-solid LVs deal with performance shortfall (or the opposite), and whether or not they have extra margin that they can "use up" somehow if not needed. But Jim seems to have answered that.
-
#26
by
simonbp
on 28 Jan, 2013 06:27
-
Yeah, the real question isn't "OMG, it's an all solid rocket", but what Ed asked earlier: What's the US government requirement that triggered OSC to develop this. They wouldn't have bothered if DoD didn't ask them to, and so there must be a class of payloads in the pipeline for it...
-
#27
by
JBF
on 28 Jan, 2013 10:55
-
Yeah, the real question isn't "OMG, it's an all solid rocket", but what Ed asked earlier: What's the US government requirement that triggered OSC to develop this. They wouldn't have bothered if DoD didn't ask them to, and so there must be a class of payloads in the pipeline for it...
As Jim said earlier, it's a case of we have all these motors, can we do anything with them.
-
#28
by
Skyrocket
on 28 Jan, 2013 11:11
-
Yeah, the real question isn't "OMG, it's an all solid rocket", but what Ed asked earlier: What's the US government requirement that triggered OSC to develop this. They wouldn't have bothered if DoD didn't ask them to, and so there must be a class of payloads in the pipeline for it...
As Jim said earlier, it's a case of we have all these motors, can we do anything with them.
But it would surely not be done without a reason, i.e. a potential payload
-
#29
by
simonbp
on 28 Jan, 2013 14:09
-
And, as noted above, it has to be a government payload, which effectively means NASA, NRO, or USAF.
A hint may be that in the fact sheet, they list performance only to very inclined orbits (SSO, 90 deg, 72 deg). It may be that OSC had inquiries about Antares polar/SSO performance, but they can't reach those orbits from MARS and a VAFB Antares pad would be expensive. So, they offer Minotaur 6 as an alternative.
Given that NRO has already launched a polar test mission on a Minotaur 1 (NROL-66), it seems reasonable that they would want a higher performance follow-up.
http://en.wikipedia.org/wiki/USA-225
-
#30
by
Proponent
on 28 Jan, 2013 22:06
-
This may be a stupid question, but when using solid upper/kick stages - I assume that they use some kind of thrust-termination to make sure that the payload is delivered in the proper orbit?
Or is that up to the payload itself to fine-tune?
There are three ways.
a. There is always some fine tuning by the payload
b. There is ballasting
c. adaptive flight control, where the vehicle dissipates excess energy with a less efficient trajectory.
I seem to recall reading that Minuteman third stages have blow-out panels so that thrust can be terminated early for precise trajectory control. Am I wrong?
-
#31
by
Jim
on 29 Jan, 2013 00:08
-
Not anymore
-
#32
by
russianhalo117
on 03 May, 2013 02:11
-
I am still skeptical and actively questioning the validity of this:
I saw that someone posted on an unofficial OSC fan site server's forum today claiming that a yet-to-be-named satellites series which is planned for the SBSS replacement programme as well as SBSS-1 when it reaches its targeted/predicted EOM will launch aboard a few Orbital Science's Minotaur-VI conversional launchers from SLC-8 near the end of this current decade.
-
#33
by
kevin-rf
on 03 May, 2013 13:14
-
Got a link to the OSC fan site?
-
#34
by
edkyle99
on 03 May, 2013 14:23
-
I am still skeptical and actively questioning the validity of this:
I saw that someone posted on an unofficial OSC fan site server's forum today claiming that a yet-to-be-named satellites series which is planned for the SBSS replacement programme as well as SBSS-1 when it reaches its targeted/predicted EOM will launch aboard a few Orbital Science's Minotaur-VI conversional launchers from SLC-8 near the end of this current decade.
Makes sense to me. The first Minotaur 4 orbited the first SBSS satellite in 2010 from SLC 8. That was near the max payload limit for that rocket. It seems likely that mass has grown for the operational satellites, which may be the reason for developing Minotaur 6.
With Antares, Stratrolaunch, and Minotaur 4,5,6, Orbital is playing with more new rockets than SpaceX these days.
- Ed Kyle
-
#35
by
Galactic Penguin SST
on 11 Aug, 2013 15:33
-
-
#36
by
russianhalo117
on 03 Apr, 2014 23:44
-
-
#37
by
Vahe231991
on 11 Jun, 2021 14:22
-