Blue Origin Thread (merged)

[fredinno]

3 hours ago, Hcube said:

There are several propulsion modules for CubeSats.

Yes, I know that, I just doubt you can fit a useful 6U cubesat with enough delta v to go from LEO or GTO to Lunar  Orbit (with the exception of maybe Solar sails).

27 minutes ago, Streetwind said:

Considering one of the Google Lunar X-Prize teams has booked flights on the Rocket Labs Electron launcher, which can lift maybe one tenth of a fully expendable Falcon 9... yes, the Falcon 9 can definitely boost things to Lunar orbit and landing.

Which is further reinforced by the fact that a different Google Lunar X-Prize team has purchased rideshare space on a (presumably non-expendable) Falcon 9 launch in order to go to the Moon. Not even a fully dedicated launch, just rideshare space (admittedly, probably as the majority share).

And a third team decided to build an extra-big lander and join forces with at least two other teams which don't have the means to build the full architecture themselves (and possibly more, as there's still lander space avialbale), with the aim of purchasing an entire Falcon 9 launch as a group at a later date.

Does that answer all questions about the F9's cislunar capabilities?

No, Electron launches closer to 1/50th of falcon 9's capacity.

Also, the Soild fuelled Minotaur V can send a 500 kg orbiter to the moon. Falcon 9 will have no problem sending payloads to TLI.

[KSK]

Some historical numbers for reference.

The Lunar Surveyors weighed approximately 1000 kg (give or take a few tens of kilograms either way) at TLI. About 2/3 of that mass was taken up by the engines (including a solid fuel retrorocket) and fuel necessary for a soft landing. They were launched on an Atlas-Centaur booster, probably using a Centaur D upper stage. (Source - Wikipedia) The Atlas Centaur was capable of launching 1,800kg to geostationary transfer orbit (source - Encyclopedia Astronautica). For comparison, the Falcon 9 can launch 4850 kg to GTO.

Moving up a level, the Viking probes (orbiter + lander) had a combined mass at launch of 3527kg. They were launched on a Titan IIIe + Centaur upper stage, capable of putting 15,400kg to LEO or 3,700kg into Trans-Mars orbit. That would be too much for a Falcon 9, but Viking was a beast of a probe. The lander or the orbiter separately? I think Falcon 9 would be capable of sending that to Mars.

So yeah, F9 is perfectly capable of cislunar missions, including lunar orbital missions, soft-landing missions, or both. It's also more than capable of lobbing CubeSats to Mars and I would guess, with a suitable propulsion system for putting them into orbit rather than just a fly-by.

Edited January 14, 2016 by KSK

[KerbonautInTraining]

4 hours ago, KSK said:

It's also more than capable of lobbing CubeSats to Mars and I would guess, with a suitable propulsion system for putting them into orbit rather than just a fly-by.

Sooo it's capable of pushing a payload with propulsion to Mars? The F9 2nd stage would be jettisoned shortly after TMI right?

[KSK]

24 minutes ago, KerbonautInTraining said:

Sooo it's capable of pushing a payload with propulsion to Mars? The F9 2nd stage would be jettisoned shortly after TMI right?

Without having any numbers to back me up, I'd presume so. I think Surveyor used a direct ascent (not sure if that's the correct terminology) where the probe was launched directly into a trans-lunar trajectory.  I would think that Falcon could do something similar for a Mars bound probe, although the upper stage could be used to put it into a parking orbit first and then be re-lit for TMI. Either way, I wouldn't expect the F9 upper stage to have enough delta-V left for Mars orbit insertion, so it would probably be jettisoned after TMI.

Edited January 14, 2016 by KSK

[sgt_flyer]

there's no reason to think F9 can't do TLI / TMI. the real question, would be how it affects maximum payload weight to be able to have enough delta-V in the upperstage for those.

now, the problem is, to know at which point it stays efficient enough alone VS adding a transfer stage to your payload and sending both to LEO with the same F9 booster.

 

[KerbonautInTraining]

6 minutes ago, sgt_flyer said:

there's no reason to think F9 can't do TLI / TMI. the real question, would be how it affects maximum payload weight to be able to have enough delta-V in the upperstage for those.

now, the problem is, to know at which point it stays efficient enough alone VS adding a transfer stage to your payload and sending both to LEO with the same F9 booster.

 

That's something I was thinking about. The mass fraction on the upper stage is already pretty huge (something like 10x heavier wet than dry) decreasing the empty mass too much would murder a lot of efficiency.

[ChrisDayVACCO]

13 hours ago, fredinno said:

I would just skip the complexity from doing that, and simply go for a Firefly Alpha or a Minotaur rocket to do that kind of job for me. Also, a propulsion system would be too big for a cubesat dispenser.

I guess it all depends on the end goal of the CubeSat.  If you want to get to Lunar orbit, the rocket's upper stage can get you there.  However, if you want to land a 6U CubeSat with today's technology, I would use the rocket's upper stage to get to low lunar orbit and then use a CubeSat propulsion system to perform the final landing.  A CubeSat thruster 1U in size can provide 697 m/s.  A larger tank for that thruster, for a 6U CubeSat, can provide ~1.7 km/s of Delta V which is just enough to land on the moon.  Here is the current propulsion system designed for a 3U CubeSat:

http://www.cubesat-propulsion.com/adn-micropropulsion-system/

[Nibb31]

Can the Falcon upper stage loiter for 3 days ? 

[Hcube]

1 hour ago, Nibb31 said:

Can the Falcon upper stage loiter for 3 days ? 

The upper stage, yes, of course ! .......The LOX inside the stage, though...

[Kartoffelkuchen]

1 hour ago, Nibb31 said:

Can the Falcon upper stage loiter for 3 days ?

Not really. Apart from its chilled propellants, irt would also need more battery power probably, since it's not designed for those long missions.

[Streetwind]

7 minutes ago, Hcube said:

The upper stage, yes, of course ! .......The LOX inside the stage, though...

Even the stage itself cannot. The main issue is actually electrical power. The stage has no solar panels (and no room to attach any), and only limited battery life. AFAIK it cannot even do full GEO missions - as in, perform both the GTO burn and the circularization burn up in GEO - because it cannot coast that long. And that's a lot less far than the Moon.

This is incidentally why ULA is doing those shenanigans with an internal combustion engine (yes, pistons and all that jazz) running off of boiloff gases for future upper stages. It'll be there simply to produce electricity during long coast phases, keeping the stage alive.

[KerbonautInTraining]

1 minute ago, Streetwind said:

This is incidentally why ULA is doing those shenanigans with an internal combustion engine (yes, pistons and all that jazz) running off of boiloff gases for future upper stages. It'll be there simply to produce electricity during long coast phases, keeping the stage alive.

Huh! I would've assumed something similar to a fuel cell would be better (no moving parts...)

I wonder how easy it is to replace the batteries in a Falcon 9 first stage, or if they would need to be replaced at all. Assuming they're using Li-On, the batteries would outlast the rest of the stage in terms of charge cycles. But that's assuming 1 charge cycle per launch... Why are the little things always so fascinating?

[ChrisDayVACCO]

40 minutes ago, KerbonautInTraining said:

Huh! I would've assumed something similar to a fuel cell would be better (no moving parts...)

I wonder how easy it is to replace the batteries in a Falcon 9 first stage, or if they would need to be replaced at all. Assuming they're using Li-On, the batteries would outlast the rest of the stage in terms of charge cycles. But that's assuming 1 charge cycle per launch... Why are the little things always so fascinating?

The batteries on the Falcon 9 are Li-ion and redundant on the first and second stages.  (I just checked on the Falcon 9 Users Guide.)  Older rocket designs used thermal batteries which were one time use.

I am glad that launch providers are moving to rechargeable batteries because this opens up more possibilities 1. of the upper stage operating as a satellite and 2. for battery testing without replacing the battery after every test.

[Kryten]

55 minutes ago, Streetwind said:

Even the stage itself cannot. The main issue is actually electrical power. The stage has no solar panels (and no room to attach any), and only limited battery life. AFAIK it cannot even do full GEO missions - as in, perform both the GTO burn and the circularization burn up in GEO - because it cannot coast that long. And that's a lot less far than the Moon.

This is incidentally why ULA is doing those shenanigans with an internal combustion engine (yes, pistons and all that jazz) running off of boiloff gases for future upper stages. It'll be there simply to produce electricity during long coast phases, keeping the stage alive.

SpaceX have stated F9 can do full GEO missions, and the Soviets demonstrated loiter times of over a week for their similar Blok D stage in the 60s.

[CatastrophicFailure]

With all this discussion on the second stage for the moment, does anyone know if SpaceX still has plans to recover and reuse them eventually?

[Kryten]

They want to do it eventually, but it's not really a plan as such right now. More of an aspiration.

[RuBisCO]

21 minutes ago, CatastrophicFailure said:

With all this discussion on the second stage for the moment, does anyone know if SpaceX still has plans to recover and reuse them eventually?

At present no one outside of SpaceX knows if they are pushing for second stage reusability yet or not.

 

[sojourner]

SpaceX was just awarded $55 million by the Airforce to develop a "raptor engine for upperstage use on F9 and FH".  Take that as you will.

[Frozen_Heart]

1 hour ago, sojourner said:

SpaceX was just awarded $55 million by the Airforce to develop a "raptor engine for upperstage use on F9 and FH".  Take that as you will.

That's odd. The Falcon 9 upper stage already has a really overpowered second stage (but inefficient), so adding an engine with 3 times the thrust won't work out. Raptor is likely to be a lot more efficient though due to the different fuel.

[sojourner]

Yeah, it even has those in the know at nasaspaceflight's forum scratching there heads.

[CatastrophicFailure]

Wait, wasn't the Raptor supposed to power the BFR/MCT?

[StrandedonEarth]

3 hours ago, CatastrophicFailure said:

With all this discussion on the second stage for the moment, does anyone know if SpaceX still has plans to recover and reuse them eventually?

Work on reusing the F9's second stage has been shelved to focus on the BFR. Source? Musk said so himself on a reddit AMA.

 

[fredinno]

10 hours ago, Streetwind said:

Even the stage itself cannot. The main issue is actually electrical power. The stage has no solar panels (and no room to attach any), and only limited battery life. AFAIK it cannot even do full GEO missions - as in, perform both the GTO burn and the circularization burn up in GEO - because it cannot coast that long. And that's a lot less far than the Moon.

This is incidentally why ULA is doing those shenanigans with an internal combustion engine (yes, pistons and all that jazz) running off of boiloff gases for future upper stages. It'll be there simply to produce electricity during long coast phases, keeping the stage alive.

Actually, Centaur now has IVF. http://forum.nasaspaceflight.com/index.php?topic=37206.0

10 hours ago, Kartoffelkuchen said:

Not really. Apart from its chilled propellants, irt would also need more battery power probably, since it's not designed for those long missions.

Can't it add solar panels (like I do in KSP)?

7 hours ago, CatastrophicFailure said:

With all this discussion on the second stage for the moment, does anyone know if SpaceX still has plans to recover and reuse them eventually?

No, they would need a rocket with a larger diameter (assuming they want to keep the current F9 payload), which is not on the table right now.

3 hours ago, CatastrophicFailure said:

Wait, wasn't the Raptor supposed to power the BFR/MCT?

It can power the 1st stage of a F9 replacement too, thankfully.

5 hours ago, Frozen_Heart said:

That's odd. The Falcon 9 upper stage already has a really overpowered second stage (but inefficient), so adding an engine with 3 times the thrust won't work out. Raptor is likely to be a lot more efficient though due to the different fuel.

Likely a downrated version- but why don't they call it a different engine then?

[Elthy]

A higher thrust upper stage could be usefull for the Falcon Heavy, with higher payloads the TWR of the second stage gets worse.

Or imagine a heavier, reusable upper stage. It would need much more fuel to get the high weight of an TPS to orbit, also it propably needs more DeltaV since the first stage couldnt throw it as fast as a lighter upper stage. Maybe SpaceX sold them their decades old dream of a cheap, reusable launcher with low turn-around times...

[fredinno]

34 minutes ago, Elthy said:

A higher thrust upper stage could be usefull for the Falcon Heavy, with higher payloads the TWR of the second stage gets worse.

Or imagine a heavier, reusable upper stage. It would need much more fuel to get the high weight of an TPS to orbit, also it propably needs more DeltaV since the first stage couldnt throw it as fast as a lighter upper stage. Maybe SpaceX sold them their decades old dream of a cheap, reusable launcher with low turn-around times...

Only thing you overlooked is that those heavy missions are for LEO- most of Falcon Heavy's missions will be for GEO, and Falcon 9 is not likely to orbit anything that maxes out its capacity to LEO anytime soon.

13 hours ago, ChrisDayVACCO said:

I guess it all depends on the end goal of the CubeSat.  If you want to get to Lunar orbit, the rocket's upper stage can get you there.  However, if you want to land a 6U CubeSat with today's technology, I would use the rocket's upper stage to get to low lunar orbit and then use a CubeSat propulsion system to perform the final landing.  A CubeSat thruster 1U in size can provide 697 m/s.  A larger tank for that thruster, for a 6U CubeSat, can provide ~1.7 km/s of Delta V which is just enough to land on the moon.  Here is the current propulsion system designed for a 3U CubeSat:

http://www.cubesat-propulsion.com/adn-micropropulsion-system/

Is there enough TWR though? (You would need landing legs too, and I'm not sure is too much useful science could be done like this...)