SpaceX Falcon Heavy Discussion (Thread 6)

[JamesH65]

In this case we don't have to think about it.

A simple comparison of the money currently being spent on FH development versus that being spent on SLS over the same period of time would be reasonable and objective. First flight dates and cost per flight/payload to orbit (mass and volume) would be reasonable metrics.

Or we could just look at it from a taxpayers perspective- I'm paying for a $3B/yr effort to develop a general purpose heavy lift vehicle for government use. And those commercial guys over there are working on their HL GP vehicle using their own money. If they can produce in the same timeframe that is cheaper to use, more readily available and I didn't have to contribute any funds to develop it, yea!

Why would I complain that they didn't deliver it sooner?

Always remember that the government get a LOT of the money spent back, directly, in the form of income taxes, indirectly in the form of shopping taxes, and even more indirectly in the fact that the programs employ a lot of people. Employed people spend more and the economy benefits. Its a VERY complicated equation, and why its large government projects  are a good thing for the economy.

Of course, there are also horrible inefficiencies.

[savuporo]

There might have been prepayments for the STP-2 mission, though I don't think the details of that contract were released.

And STP-2 should be a lesson to anyone thinking people will be on Mars in their lifetimes. Years of delays in getting critical enabling technologies like DSAC and GPIM flight tested, nobody gets fired or loses their shirt.

[wannamoonbase]

There might have been prepayments for the STP-2 mission, though I don't think the details of that contract were released.

And STP-2 should be a lesson to anyone thinking people will be on Mars in their lifetimes. Years of delays in getting critical enabling technologies like DSAC and GPIM flight tested, nobody gets fired or loses their shirt.

I'll be happy to see people walk and hopefully live on the moon in my lifetime (44 years old.)

FH get's us closer to that.

[the_other_Doug]

Clearly they have the stages tested and on site, and have applied/received launch/landing license.

Consider FH another means to apply booster reuse, just more of them at once.

No surprise that 40 is taking time to rebuild/refit.

What threatens past that is unresolved issues with getting to static fire that might delay months. Like constantly messing with TE/launch mount/other due to issues.

The vehicle strategy seems more than good enough.

They'll be within two months once a launch is scheduled for LC40. They'll be within a month once they have the vehicle erect and stop fiddling with TE/launch mount.

I believe it's more to do with the launch mounts than the TEL.  AIUI, the TEL at 39A was designed from the start to eventually support FH launches.  They only need to complete the plumbing connections to the side cores, as far as the TEL is concerned, and as I say, I believe all the appropriate basic plumbing was built into the thing already.

ISTR that just getting the single launch mount installed for F9 at 39A took several months, and that was after a delay engendered by getting the new launch mount, for F9 V1.2, installed at Vandenberg.  Heck, I can't even tell you for certain that correctly positioned holes into the launcher deck, feeding down into the flame pit, have been opened up at 39A to sit beneath the side cores, much less work begun on the supporting structures for the additional launch mounts.  (I hope they have, and I can't believe SpaceX's schedules if they haven't, but still...)

In other words, we don't know exactly where the 39A FH modification work stands at present.  We know that, starting from an unmodified launcher deck, it could take several months to complete the 39A modifications.  Of course, SpaceX seems to have projected only a couple of months, once LC40 is ready to go, to get the work done.  But this could be expressed in the SpaceX month time unit, and we all know about that one...

[old_sellsword]

...In other words, we don't know exactly where the 39A FH modification work stands at present...

We do actually. The only big ticket items left at 39A for FH are the six outer holddown clamps and the four outer tail service masts.

That’s by no means saying those will be “easy” to install and test, but there aren’t any large modifications to be done outside work on the top of the reaction frame.

[Tomness]

We do actually. The only big ticket items left at 39A for FH are the six outer holddown clamps and the four outer tail service masts.

That’s by no means saying those will be “easy” to install and test, but there aren’t any large modifications to be done outside work on the top of the reaction frame.

I wonder about the ground infrastructure pluming, tanks, gse..etc., that is needed for falcon heavy and whether it was scraficed to SLC- 40 to speed up it's activation ... not less those items are not long lead items and neather need for slc-40.

[smfarmer11]

With a lot more all electric satellites coming out, could the FH get in on the market for those? The transfer time for these satellites being four or more months. If the upper stage had the loiter time, could the extra launch cost of a direct to GEO insertion be offset by satellite earnings and lifetime extension? It could also allow for heavier communications payloads.

[DreamyPickle]

With a lot more all electric satellites coming out, could the FH get in on the market for those? The transfer time for these satellites being four or more months. If the upper stage had the loiter time, could the extra launch cost of a direct to GEO insertion be offset by satellite earnings and lifetime extension? It could also allow for heavier communications payloads.

The shift towards more electric satellites benefits the regular Falcon 9 more because they are lighter on average and can be launched in reusable mode. Their competition needs to juggle agreements for double launches instead.

Also as far as I remember there was no indication from SpaceX that they're looking to improve S2 loiter time or perform direct injections, just a lot of fan rumors. The second stage is shared with the regular F9 and complex orbital maneuvers are not it's strong suit. It's cheap and powerful and restartable but it has not yet demonstrated more than half an hour orbital lifetime.

[Herb Schaltegger]

Also as far as I remember there was no indication from SpaceX that they're looking to improve S2 loiter time or perform direct injections, just a lot of fan rumors.

There is info in L2.

[guckyfan]

Also as far as I remember there was no indication from SpaceX that they're looking to improve S2 loiter time or perform direct injections, just a lot of fan rumors.

I don't think the SpacX website on FH counts as fan rumor. It clearly states capability of direct GEO insertion.

[cppetrie]

...but it has not yet demonstrated more than half an hour orbital lifetime.

Didn't they do an extended loiter experiment after one of the launches earlier this summer? Can't recall which, maybe the NROL mission? IIRC it was a 12 or 24 hour loiter.

[old_sellsword]

Also as far as I remember there was no indication from SpaceX that they're looking to improve S2 loiter time or perform direct injections...

...but it has not yet demonstrated more than half an hour orbital lifetime.

SpaceX demonstrated a multi-hour coast and successfully restart (to deorbit) after payload separation on NROL-76 earlier this year. This was the first flight of a Block 4 upper stage, so I wouldn’t be surprised if Block 5 upper stages are upgraded enough for full GSO insertion.

Source

Following the launch of the NROL-76 spacecraft on Monday – which also included a successful Second Stage extended coast test...

... The NROL-76 mission also provided additional data points on the performance and utilization of the Second Stage, per future mission objectives. The test – which occurred after spacecraft separation – involved a “super long” coast phase demo, according to L2 information.

[envy887]

SpaceX has already demonstrated multi hour upper stage endurance, and plans to offer direct insertion for DoD missions.

I don't see any reason to expect commercial customers to go with direct insertion though.

[DreamyPickle]

Sorry, I was wrong. I missed the long duration coast experiment a few launches back.

Still, it seems that this is mostly for DoD requirements. I'm not sure the F9 is particularly good at direct injection. For something like the Centaur you are using a high-isp engine for injection which means you can lift a heavier mass to the final orbit. But if you're launching on the Falcon I'm not sure there is much advantage compared to having a bigger hydrazine tank.

However satellites vary in size instead of being sized for particular launchers so maybe it's beneficial to use up any extra performance.

[jpo234]

SpaceX has already demonstrated multi hour upper stage endurance, and plans to offer direct insertion for DoD missions.

I don't see any reason to expect commercial customers to go with direct insertion though.

Direct insertion seems very useful for satellites with electric propulsion. This could eliminate or shorten the time to the final GEO slot.

[vaporcobra]

SpaceX has already demonstrated multi hour upper stage endurance, and plans to offer direct insertion for DoD missions.

I don't see any reason to expect commercial customers to go with direct insertion though.

Direct insertion seems very useful for satellites with electric propulsion. This could eliminate or shorten the time to the final GEO slot.

While we're getting pretty off topic, it's worth remembering that electric propulsion was really only adopted for satellites in Earth orbit because of its efficiency. Better ISP means less reaction mass is needed, and those weight savings translate into larger revenue-generating payloads for an electric sat with the same mass as a chemical sat. The trade-off is the time it takes ion propulsion to bring a satellite to its operational orbit.

FH is probably only an economical option for satellite operators as a reusable vehicle, which allows for 8 metric tons to GTO. There are very few current commercial payloads that are that heavy, so it's far more probable that satellite operators modify future sats to incorporate far more revenue-generating payload per launch.

Even still, FH could crush Ariane 5 ECA in a competition for $/kg to GTO as an expendable vehicle, even if it only used half of its 22,500 kg GTO capability and adopted Arianespace's ride share strategy. In fact, I suspect the margin left over from launching 2x5000kg geosats would allow SpaceX to either attempt recovery of the side boosters, or place both of those satellites directly into GEO.

[envy887]

SpaceX has already demonstrated multi hour upper stage endurance, and plans to offer direct insertion for DoD missions.

I don't see any reason to expect commercial customers to go with direct insertion though.

Direct insertion seems very useful for satellites with electric propulsion. This could eliminate or shorten the time to the final GEO slot.

While we're getting pretty off topic, it's worth remembering that electric propulsion was really only adopted for satellites in Earth orbit because of its efficiency. Better ISP means less reaction mass is needed, and those weight savings translate into larger revenue-generating payloads for an electric sat with the same mass as a chemical sat. The trade-off is the time it takes ion propulsion to bring a satellite to its operational orbit.

FH is probably only an economical option for satellite operators as a reusable vehicle, which allows for 8 metric tons to GTO. There are very few current commercial payloads that are that heavy, so it's far more probable that satellite operators modify future sats to incorporate far more revenue-generating payload per launch.

Even still, FH could crush Ariane 5 ECA in a competition for $/kg to GTO as an expendable vehicle, even if it only used half of its 22,500 kg GTO capability and adopted Arianespace's ride share strategy. In fact, I suspect the margin left over from launching 2x5000kg geosats would allow SpaceX to either attempt recovery of the side boosters, or place both of those satellites directly into GEO.

All-electric geosats are a manifestation of the fact that more payload on orbit (or the same payload on a smaller cheaper rocket) is often better than quicker time to orbit. Extending the paradigm to Falcon Heavy logically leads to 10 tonne or larger all-electric sats, not direct insertion of smaller sats.

This is a complex multivariable optimization problem, and we don't have enough information to solve it definitively. But the evidence I see does not indicate direct insertion.

[DreamyPickle]

FH is probably only an economical option for satellite operators as a reusable vehicle, which allows for 8 metric tons to GTO. There are very few current commercial payloads that are that heavy, so it's far more probable that satellite operators modify future sats to incorporate far more revenue-generating payload per launch.

After a brief web search it seems the heaviest commercial GTO payload to date is TerraStar-1 at 6910 kg. This is only slightly heavier than the heaviest Falcon 9 GTO launch, Intelsat 35e at 6761 kg. And that mission exceeded it's orbital requirements!

The chinese Shijian-18 was over 7 tons but the launch failed. There are maybe other heavier satellites that are classified, for example from Delta IV Heavy GTO launches.

[vaporcobra]

SpaceX has already demonstrated multi hour upper stage endurance, and plans to offer direct insertion for DoD missions.

I don't see any reason to expect commercial customers to go with direct insertion though.

Direct insertion seems very useful for satellites with electric propulsion. This could eliminate or shorten the time to the final GEO slot.

While we're getting pretty off topic, it's worth remembering that electric propulsion was really only adopted for satellites in Earth orbit because of its efficiency. Better ISP means less reaction mass is needed, and those weight savings translate into larger revenue-generating payloads for an electric sat with the same mass as a chemical sat. The trade-off is the time it takes ion propulsion to bring a satellite to its operational orbit.

FH is probably only an economical option for satellite operators as a reusable vehicle, which allows for 8 metric tons to GTO. There are very few current commercial payloads that are that heavy, so it's far more probable that satellite operators modify future sats to incorporate far more revenue-generating payload per launch.

Even still, FH could crush Ariane 5 ECA in a competition for $/kg to GTO as an expendable vehicle, even if it only used half of its 22,500 kg GTO capability and adopted Arianespace's ride share strategy. In fact, I suspect the margin left over from launching 2x5000kg geosats would allow SpaceX to either attempt recovery of the side boosters, or place both of those satellites directly into GEO.

All-electric geosats are a manifestation of the fact that more payload on orbit (or the same payload on a smaller cheaper rocket) is often better than quicker time to orbit. Extending the paradigm to Falcon Heavy logically leads to 10 tonne or larger all-electric sats, not direct insertion of smaller sats.

This is a complex multivariable optimization problem, and we don't have enough information to solve it definitively. But the evidence I see does not indicate direct insertion.

Agreed. So long as satellite operators plan on extra time to reach operational orbit, it will always be better to include more revenue-relevant payload instead of more fuel. It is indeed a highly complex optimization problem.

[jfallen]

Isn't it about time to move this discussion to the Missions section and create an updates thread.  I anticipate there being some updates in the next couple of weeks on the timing.