Countdown to new smallsat launchers

[Robotbeat]

It absolutely does make a practical difference. Peroxide stores for a long time. LOx doesn't, needs to be replenished constantly. Because of surface area to volume ratio, this is more significant for larger vehicles. Thermal concerns are less of an issue for bigger vehicles.

Peroxide was used by Unreasonable Rocket's Blue Ball for the NGLLC, and did quite well considering it was basically a garage project.

Peroxide costs more if you buy it by the multiple  ton than oxygen does, but peroxide is cheaper if you're just using a few liters here and there since it sticks around.

With peroxide, you can start with a mono prop for testing and graduate to a biprop. I just don't think you'd bother doing that for a large vehicle, so you don't get that advantage.

Again, I definitely think peroxide looks more interesting if you're building a smaller vehicle.

[savuporo]

Peroxide costs more if you buy it by the multiple  ton than oxygen does, but peroxide is cheaper if you're just using a few liters here and there since it sticks around...

I think a reasonable argument is that a few liters here and there doesn't make you a credible project to go to space, never-mind orbit.
If you aren't setting up to handle and use at least tens of tons of propellant on a regular basis, you aren't going to space anyway.

[QuantumG]

Storing large qualities of peroxide is more costly than just getting LOX trucked in, if you have the option. I like peroxide for the non-cryogenic simplicity, and the small batch advantages, and for the not-having-to-explain-why-you-want-LOX-in-Australia ease, but that's about it.

[Robotbeat]

Peroxide costs more if you buy it by the multiple  ton than oxygen does, but peroxide is cheaper if you're just using a few liters here and there since it sticks around...

I think a reasonable argument is that a few liters here and there doesn't make you a credible project to go to space, never-mind orbit.
If you aren't setting up to handle and use at least tens of tons of propellant on a regular basis, you aren't going to space anyway.

That really depends. A nanosat launcher may only use a couple tons, and initial tests can be done with a few dozen liters. If you're shooting for just the Karman Line, then you don't even need a ton.

[CameronD]

It absolutely does make a practical difference. Peroxide stores for a long time. LOx doesn't, needs to be replenished constantly. Because of surface area to volume ratio, this is more significant for larger vehicles. Thermal concerns are less of an issue for bigger vehicles.

Peroxide was used by Unreasonable Rocket's Blue Ball for the NGLLC, and did quite well considering it was basically a garage project.

Peroxide costs more if you buy it by the multiple  ton than oxygen does, but peroxide is cheaper if you're just using a few liters here and there since it sticks around.

With peroxide, you can start with a mono prop for testing and graduate to a biprop. I just don't think you'd bother doing that for a large vehicle, so you don't get that advantage.

Again, I definitely think peroxide looks more interesting if you're building a smaller vehicle.

It's interesting then that Rocketlab (for one) don't agree with you.

As QG said, storing large qualities of peroxide is more costly than just getting LOX trucked in, if you have the option.  There are OH&S issues with both, but as I posted, at end of the day if you can't get HTP anyplace nearby (we can't even buy RP1 - that has to be imported from the USA at horrendous $$ per liter!) then you really need to find an alternative... and air is everywhere.
 

[Katana]

Peroxide costs more if you buy it by the multiple  ton than oxygen does, but peroxide is cheaper if you're just using a few liters here and there since it sticks around...

I think a reasonable argument is that a few liters here and there doesn't make you a credible project to go to space, never-mind orbit.
If you aren't setting up to handle and use at least tens of tons of propellant on a regular basis, you aren't going to space anyway.

That really depends. A nanosat launcher may only use a couple tons, and initial tests can be done with a few dozen liters. If you're shooting for just the Karman Line, then you don't even need a ton.

Shooting for just the Karman Line need tons too, for repeative ground testing (troubleshooting, engine reliability qualification, GNC and hovering). Suppose as small as 100kg each time.

[Katana]

The Soyuz rocket uses peroxide today to drive turbopumps, and uses peroxide as a mono propellant on the capsule.

It's in use commercially. I'd say it's worth considering for small vehicles. For big rockets, you might as well go with LOx.

Peroxide turbopump is a wise choice for small rockets, simpler gas generator system and no char pollution problem of kerosene gas generator (more severe on small scale).

[savuporo]

Shooting for just the Karman Line need tons too, for repeative ground testing (troubleshooting, engine reliability qualification, GNC and hovering). Suppose as small as 100kg each time.

Exactly. Nobody's going to space before they have burnt tens tons of propellant and hopefully very few facilities in the process.

[Katana]

Shooting for just the Karman Line need tons too, for repeative ground testing (troubleshooting, engine reliability qualification, GNC and hovering). Suppose as small as 100kg each time.

Exactly. Nobody's going to space before they have burnt tens tons of propellant and hopefully very few facilities in the process.

The minimium may be the CSXT , ~200kg each launch a few times, total propellant cost around a couple of tons including ground tests.

Solids are simpler and require less testing even when build in house. Its rather strange that most new emerging small launcher projects leaps to liquids, not solids.

Handeling of AP oxidizer is simpler than Peroxide, while regulation issue is only slightly more difficult.

[savuporo]

Solids are simpler and require less testing even when build in house. Its rather strange that most new emerging small launcher projects leaps to liquids, not solids.

Idk but Super Strypi and SS-520 didn't do a good job of persuading people otherwise.

[Robotbeat]

It absolutely does make a practical difference. Peroxide stores for a long time. LOx doesn't, needs to be replenished constantly. Because of surface area to volume ratio, this is more significant for larger vehicles. Thermal concerns are less of an issue for bigger vehicles.

Peroxide was used by Unreasonable Rocket's Blue Ball for the NGLLC, and did quite well considering it was basically a garage project.

Peroxide costs more if you buy it by the multiple  ton than oxygen does, but peroxide is cheaper if you're just using a few liters here and there since it sticks around.

With peroxide, you can start with a mono prop for testing and graduate to a biprop. I just don't think you'd bother doing that for a large vehicle, so you don't get that advantage.

Again, I definitely think peroxide looks more interesting if you're building a smaller vehicle.

It's interesting then that Rocketlab (for one) don't agree with you.

As QG said, storing large qualities of peroxide is more costly than just getting LOX trucked in, if you have the option.  There are OH&S issues with both, but as I posted, at end of the day if you can't get HTP anyplace nearby (we can't even buy RP1 - that has to be imported from the USA at horrendous $$ per liter!) then you really need to find an alternative... and air is everywhere.
 

Where did this idea come from that there can only be One True Way to do everything?

[CameronD]

Where did this idea come from that there can only be One True Way to do everything?

New Zealand. 

[Robotbeat]

"One propellant combination to rule them all..."

[Steven Pietrobon]

I like peroxide for the non-cryogenic simplicity, and the small batch advantages, and for the not-having-to-explain-why-you-want-LOX-in-Australia ease, but that's about it.

You also need to explain why you need HTP in Australia, as its a chemical also used in drug making.

It's interesting then that Rocketlab (for one) don't agree with you.

If you're using the same propellant for the first and second stage, then kerolox gives better performance as the large delta-v (about 9 km/s), the higher Isp makes up for the lower density compared to keroxide. My ideal rocket has keroxide on the first stage (with 7 engines to allow reuse) and hydrolox on the second stage (with 5 engines to also reuse).

[Katana]

Solids are simpler and require less testing even when build in house. Its rather strange that most new emerging small launcher projects leaps to liquids, not solids.

Idk but Super Strypi and SS-520 didn't do a good job of persuading people otherwise.

L-4S modified from sounding rocket succeed in the 1970s.

Most failed solid programs fail on GNC, while most failed liquid programs perish before full sized launch.

[Robotbeat]

Of course, if you recover liquid engines, you could fuel them up fairly easily and fly again. For solids, you might as well build a new motor because reuse doesn't save money.

That's why I think many companies are pursuing liquid engines. Combined with the fact that a much greater degree of control is possible with liquids and performance is significantly higher (Isp and mass fraction). For a solid rocket, you need more stages, and you need a final liquid stage anyway if you want anything like a precision orbital insertion (which most payloads want).

From the SLS thread, which was going off topic.

Expanding on this:

Look at Pegasus. It's 3 solid stages and a small liquid stage to null out the dispersion from the previous stages. Even though it's air-launched. To get it launched from the ground, you'd need another solid stage, like Taurus. So you're up to 5 stages, all of them with different combustion characteristics due to different chamber sizes, etc. and the last one (which is optional but a necessary for most payloads) is liquid anyway.

Even if solids are easier (they kind of are), the overall rocket needs 5 stages with a whole bunch of staging events and different tests needed on each. That's very complicated and likely to fail. Pegasus has a decent reliability, but it didn't start that way.

With liquids, you can use just two stages. And you can cluster, allowing you to use the same engine for both stages (although long-term, you'd probably be encouraged to change the upper stage for optimal performance).

Heck, you can even do it with a single stage if you have a pump fed engine of high performance. Probably a better approach would be like the Russians did with R7/Sputnik:

Parallel stages with everything using the same engine type and everything lit on the ground. Surprised no one has taken that approach, since it seems easiest to test. I think I'd take that approach if I were developing a LEO nanosat launcher. Atlas (the original) was similar, but just staged off the engines (which is more complicated than the R7 approach and also requires really good tank mass fraction).

[Galactic Penguin SST]

Of course, if you recover liquid engines, you could fuel them up fairly easily and fly again. For solids, you might as well build a new motor because reuse doesn't save money.

That's why I think many companies are pursuing liquid engines. Combined with the fact that a much greater degree of control is possible with liquids and performance is significantly higher (Isp and mass fraction). For a solid rocket, you need more stages, and you need a final liquid stage anyway if you want anything like a precision orbital insertion (which most payloads want).

From the SLS thread, which was going off topic.

Expanding on this:

Look at Pegasus. It's 3 solid stages and a small liquid stage to null out the dispersion from the previous stages. Even though it's air-launched. To get it launched from the ground, you'd need another solid stage, like Taurus. So you're up to 5 stages, all of them with different combustion characteristics due to different chamber sizes, etc. and the last one (which is optional but a necessary for most payloads) is liquid anyway.

Even if solids are easier (they kind of are), the overall rocket needs 5 stages with a whole bunch of staging events and different tests needed on each. That's very complicated and likely to fail. Pegasus has a decent reliability, but it didn't start that way.

With liquids, you can use just two stages. And you can cluster, allowing you to use the same engine for both stages (although long-term, you'd probably be encouraged to change the upper stage for optimal performance).

Heck, you can even do it with a single stage if you have a pump fed engine of high performance. Probably a better approach would be like the Russians did with R7/Sputnik:

Parallel stages with everything using the same engine type and everything lit on the ground. Surprised no one has taken that approach, since it seems easiest to test. I think I'd take that approach if I were developing a LEO nanosat launcher. Atlas (the original) was similar, but just staged off the engines (which is more complicated than the R7 approach and also requires really good tank mass fraction).

OTRAG?

[HMXHMX]

Of course, if you recover liquid engines, you could fuel them up fairly easily and fly again. For solids, you might as well build a new motor because reuse doesn't save money.

That's why I think many companies are pursuing liquid engines. Combined with the fact that a much greater degree of control is possible with liquids and performance is significantly higher (Isp and mass fraction). For a solid rocket, you need more stages, and you need a final liquid stage anyway if you want anything like a precision orbital insertion (which most payloads want).

From the SLS thread, which was going off topic.

Expanding on this:

Look at Pegasus. It's 3 solid stages and a small liquid stage to null out the dispersion from the previous stages. Even though it's air-launched. To get it launched from the ground, you'd need another solid stage, like Taurus. So you're up to 5 stages, all of them with different combustion characteristics due to different chamber sizes, etc. and the last one (which is optional but a necessary for most payloads) is liquid anyway.

Even if solids are easier (they kind of are), the overall rocket needs 5 stages with a whole bunch of staging events and different tests needed on each. That's very complicated and likely to fail. Pegasus has a decent reliability, but it didn't start that way.

With liquids, you can use just two stages. And you can cluster, allowing you to use the same engine for both stages (although long-term, you'd probably be encouraged to change the upper stage for optimal performance).

Heck, you can even do it with a single stage if you have a pump fed engine of high performance. Probably a better approach would be like the Russians did with R7/Sputnik:

Parallel stages with everything using the same engine type and everything lit on the ground. Surprised no one has taken that approach, since it seems easiest to test. I think I'd take that approach if I were developing a LEO nanosat launcher. Atlas (the original) was similar, but just staged off the engines (which is more complicated than the R7 approach and also requires really good tank mass fraction).

OTRAG?

OTRAG staged parallel mechanically, but ignited sequentially.  At least that's my memory from getting briefed by Kayser in 1978 in Munich. 

[Robotbeat]

Yeah, OTRAG is taking it to an extreme, and I don't think it's all groundlit.

R7 is a good compromise. Pumpfed, but not trying to do SSTO. Clustered, but only 5 elements (not dozens).

[QuantumG]

I like peroxide for the non-cryogenic simplicity, and the small batch advantages, and for the not-having-to-explain-why-you-want-LOX-in-Australia ease, but that's about it.

You also need to explain why you need HTP in Australia, as its a chemical also used in drug making.

Mates and I have bought tons of it without trouble. LOX is a game of 20 questions with "no" at the end.