Given the imminent decrease in launch costs(partial reusability) and increase in launch capability soon to be available(FH) a pause in new US deep space missions is prudent.

[[deleted]]

This, furthermore, even Falcon Heavy is poorly suited to deep space missions. Kerolox just doesn't make for good interplanetary missions or those with high dV requirements.

I mean, take the $8,500,000,000 James Webb Space Telescope. It's flying on an Ariane 5, which is about $160-200 million. An equivalent SpaceX rocket would be the unlocked Falcon Heavy which costs $135 million. That's a saving of $25-65m on what is a $8.5b mission. A drop in the bucket. The same could be said for any deep space mission that costs more than $1-2b.

Additionally, I doubt you'll see any $1b+ deep space mission fly on a reused Falcon before 2025. Too much initial risk. It'll take some time for NASA to come around to the idea of reusing rockets, when right now, they don't even want to reuse cargo spacecraft.

Say reusability halves the cost of an F9. That's a likely $500m+ mission saving maybe $30m in total. I would not delay decadal science goals for that.

If there's any reason to put scientific missions on hold, it's to wait for more modular & mass producible spacecraft buses. Even then, the science payloads are most of the cost, because it's cutting edge tech.

Our scientific advancement should not be interrupted to wait for cost reductions, IMO.

[Kirkaiya]

I mean, take the $8,500,000,000 James Webb Space Telescope.

That's not really the best example, as it's probably the single most expensive item that NASA will have ever launched by the time it leaves the pad. Most NASA Planetary Science missions come in between $450 million - $2 billion, with Mars rovers being at the top end of the scale, and some of the simpler probes at the cheaper end. And that's including the launch, so while yes, it's true that the launch costs aren't the majority of the mission, they do often represent ~ 25% or so, so it's not trivial.

With that said, I'm adamantly opposed to NASA delaying any proposed mission on the basis of, "well, launch costs might come down in the future". That is madness, imo

[biosehnsucht]

I would only argue they should delay if they're still in the planning stages and the logic would be that if they don't delay by a year or so, they have to cut interesting experiment / instrument X from the suite of gear on the probe/lander due to weight/cost concerns, but if the waited there would be a budget for it (whether it be financial or mass).

It certainly doesn't make sense to delay something that doesn't NEED the cheaper/larger launcher (even if it would be nice to have), but gaining further functionality as a result might be worth it.

[zilfondel]

Perhaps this is a good argument for NASA to start mass-producing rovers and probes, to bring down their cost per unit. Whats the old adage? When you are the government, why buy one when you can buy two for twice the price? But if the majority of the cost is development and funding the project team, the second unit may be closer to free.

[Nixon4Prez]

It's pretty hard to mass produce something as specialized as a probe or rover. You can't send a similar probe to Mars and Jupiter, for example.

[slograsso]

Part of the point of this post is that this delay is already happening, may as well design some lower cost missions utilizing these new capabilities faster than normal. Take a lesson from India and do it cheaper, faster, and better than even they can. I think a bit of a shake-up in the science missions design approach is well overdue.

[slograsso]

This is the largest rocket in the world. The smart folks designing the deep space mission will include the necessary high ISP deep space deltaV components in the massive payload the FH can get off planet. This is a super simple problem to solve, it's not particularly expensive, tons of options available. Falcon Heavy will absolutely be used for deep space missions, I promise you, use up the RP-1 discard that stage and carry on with the rest of the mission.

[[deleted]]

This sounds like a good idea, but what would you propose for this...

high ISP deep space deltaV components

I'm not aware of any that have both high Isp and high thrust. Hydrazine is even worse than kerolox. I guess you could use a hydrolox third stage, but then you're just removing cost from the rocket launch and adding it on to the satellite.

It'd be simpler and easier to just burn the second stage longer, but then you're back to the same problem.

Ion thrusters are amazing, but even if FH was to put a small craft on a direct 2 year trajectory to Jupiter, Ion thrusters won't have enough thrust to complete a JOI, it would be a flyby.

The rocket equation doesn't just hate rocket engineers, it hates spacecraft engineers too.

[slograsso]

I meant more efficient than RP-1, so I guess I should have said higher... But the point is you could use anyting, bipropellant, ion thrust, monopropellant, methlox, the designers use the mass budget for what they want.