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Starship lets you trade money and mission complexity for time. A fully refueled Starship in LEO should have around 5km/s in an expendable configuration. A gravi

Starship lets you trade money and mission complexity for time. A fully refueled Starship in LEO should have around 5km/s in an expendable configuration. A gravity assist from Earth or Mars typically provides 2-5km/s. Looking at the https://www.reddit.com/r/space/comments/1ktjfi/deltav_map_of_the_solar_system/ https://www.reddit.com/r/space/comments/1ktjfi/deltav_map_of... 5km/s from LEO is barely enough to reach Jupiter. Looking at the mission trajectory direct launch would shave off roughly 2 years from 5 year mission - https://europa.nasa.gov/mission/timeline/ https://europa.nasa.gov/mission/timeline/ You could also launch much-much heavier probe with a dedicated boost stage and / or electric propulsion...

ANewFormation 2y ago
The largest probe ever launched afaik is Voyager 1, and it was less than a ton. Even 'massive' things like the James Webb telescope only weighs 7 tons. Starship is aiming for being able to launch 200+ tons. So stuff like this on a dedicated mission would have vastly more delta-v available but also be kind of silly. There's no reason we couldn't scale things up and just launch hundreds of probes at once all through the Solar System. Alternatively instead of launching probes we could look to start launching modular observation stations that could one day even house humans, or perhaps even grander ideas. Launching one off probes, rovers, and satellites is really something I think we should be aiming to move beyond, let alone on the ridiculous time intervals we operate on at present. We shouldn't still be making basic, yet revolutionary, discoveries on the Moon, more than half a century after we set foot on it.
- baq 2y ago
  Comms is the reason. DSN dish time is not a particularly abundant resource even today.
  - rbanffy 2y ago
    The far side of the moon is prime real estate for radiotelescopes. You can create a sizable expansion of the DSN by sharing dish time with the antennas you can build from local materials.
  - philistine 2y ago
    Well I fully assume that the DSN itself will move to space, courtesy of Starship's large tonnage to orbit.
  - Melatonic 2y ago
    I've been thinking for years we should built a space network of probe and satellite like objects - imagine if we landed a small relay on every asteroid passing anywhere near earth - could be highly useful for communication and possibly also give us a GPS like location assist for additional spacecraft
AlessandroF6587 2y ago
Starship can be used to release a probe with gigantic fuel reserve and a bigger than usual energy source (solar or nuclear). Then the probe can use a VASMIR or other electric propulsion to gradually accumulate a vast amount of delta-v
sandworm101 2y ago
A fully refueled starship in leo is a big big ask, akin to getting a full shuttle stack into orbit. On-orbit refueling at such a scale has not been done yet and is difficult to even think about doing. It isnt like KSP. The more efficient route would be to scrap starship and design a high-energy upper stage to be launched by the BFR instead, a purpose-built probe thrower. Starship is way to heavy to be a practical final stage for probes.
- Alex-Programs 2y ago
  On-orbit refuelling at such a scale does sound rather difficult, but they also fully intend to do it in the near future. They're certainly going to give it a good try. Also, if you don't want to make an entirely different second stage to put on top of superheavy, you should be able to fit a pretty substantial third stage in Starship's payload bay. Right now the payload bay doesn't open anywhere near enough for that, but hopefully in the future that'll be an option. And if you really want to make something go fast, you could refuel in orbit, give it a push from Starship, then deploy the third stage for another kick.
  - rbanffy 2y ago
    > Right now the payload bay doesn't open anywhere near enough for that Shouldn't be too hard to design a starship with a blunt nose and place it under an expendable fairing. With a 1-ton probe the budget is 99 tons for a kick stage. That's a lot of delta-v. With some creative propulsion options, maybe even interstellar probes can be done.
- sneak 2y ago
  Everything you said is right, but on-orbit refueling is of course theoretically possible, and isn’t THAT huge of a leap given what SpaceX has already accomplished. Let’s not forget the space lasers, or the chopstick catch, or Starlink-live-streamed 4K views from the plasma shadow during reentry, or autonomous Dragon docking, etc. Sure, it’s hard, but that is perhaps the best engineering team in the history of humankind, and I think they’re up to the task. Additionally, people much smarter than me ALSO think they are up to the task, and they have more and higher-resolution data about the problem space, too. My money’s on they get it working. Maybe it takes five years or a dozen failures, but I’m confident that they will succeed eventually and there will be orbiting methane and lox fuel stations sooner rather than later.
perihelions 2y ago
- "A fully refueled Starship in LEO should have around 5km/s in an expendable configuration." That can't be right; a naive application of the rocket equation gives (3.72 km/s) * ln(1,300 mT / 100 mT) = 9.55 km/s.
- TrainedMonkey 2y ago
  It's definitely higher than 5km/s, but I would not go up to 9.5km/s. My napkin math was - booster provides 2km/s and the LEO is 7.2km/s, so if the ship arrives nearly empty LEO it must provide a minimum 5.2km/s. I did not account for gravity + friction losses which could be guesstimated to 2km/s. If we assume that ship handles all of them (which is not true booster does some) we come up to 5 + 2 = 7.2km/s. The equation you have uses block 1 prop + dry mass numbers. Block 1 does not have significant payload capability and the last one just flow on OFT 6. As such let's use Block 2 numbers, first one should fly early next year. Dry mass target 100t, payload 100t, prop mass 1,500t. So (3.72 km/s) * ln(1700 / 200) = 7.96 km /s. This is with using min advertised payload of 100t and Elon's forward looking 100t number for dry mass. Way above 5km/s, but reaching 9.5km/s with 100t of payload will be challenging. I've pulled stats from https://en.wikipedia.org/wiki/SpaceX_Starship https://en.wikipedia.org/wiki/SpaceX_Starship .
  - perihelions 2y ago
    You're mixing up unrelated concepts. In particular, the payload capacity to LEO of 100 tonnes has nothing to do with this calculation. Europa Clipper isn't a 100 tonne payload; it's about 6.

ANewFormation 2y ago

The largest probe ever launched afaik is Voyager 1, and it was less than a ton. Even 'massive' things like the James Webb telescope only weighs 7 tons. Starship is aiming for being able to launch 200+ tons. So stuff like this on a dedicated mission would have vastly more delta-v available but also be kind of silly. There's no reason we couldn't scale things up and just launch hundreds of probes at once all through the Solar System. Alternatively instead of launching probes we could look to start launching modular observation stations that could one day even house humans, or perhaps even grander ideas. Launching one off probes, rovers, and satellites is really something I think we should be aiming to move beyond, let alone on the ridiculous time intervals we operate on at present. We shouldn't still be making basic, yet revolutionary, discoveries on the Moon, more than half a century after we set foot on it.

baq 2y ago
Comms is the reason. DSN dish time is not a particularly abundant resource even today.
- rbanffy 2y ago
  The far side of the moon is prime real estate for radiotelescopes. You can create a sizable expansion of the DSN by sharing dish time with the antennas you can build from local materials.
- philistine 2y ago
  Well I fully assume that the DSN itself will move to space, courtesy of Starship's large tonnage to orbit.
- Melatonic 2y ago
  I've been thinking for years we should built a space network of probe and satellite like objects - imagine if we landed a small relay on every asteroid passing anywhere near earth - could be highly useful for communication and possibly also give us a GPS like location assist for additional spacecraft

AlessandroF6587 2y ago

Starship can be used to release a probe with gigantic fuel reserve and a bigger than usual energy source (solar or nuclear). Then the probe can use a VASMIR or other electric propulsion to gradually accumulate a vast amount of delta-v

sandworm101 2y ago

A fully refueled starship in leo is a big big ask, akin to getting a full shuttle stack into orbit. On-orbit refueling at such a scale has not been done yet and is difficult to even think about doing. It isnt like KSP. The more efficient route would be to scrap starship and design a high-energy upper stage to be launched by the BFR instead, a purpose-built probe thrower. Starship is way to heavy to be a practical final stage for probes.

Alex-Programs 2y ago
On-orbit refuelling at such a scale does sound rather difficult, but they also fully intend to do it in the near future. They're certainly going to give it a good try. Also, if you don't want to make an entirely different second stage to put on top of superheavy, you should be able to fit a pretty substantial third stage in Starship's payload bay. Right now the payload bay doesn't open anywhere near enough for that, but hopefully in the future that'll be an option. And if you really want to make something go fast, you could refuel in orbit, give it a push from Starship, then deploy the third stage for another kick.
- rbanffy 2y ago
  > Right now the payload bay doesn't open anywhere near enough for that Shouldn't be too hard to design a starship with a blunt nose and place it under an expendable fairing. With a 1-ton probe the budget is 99 tons for a kick stage. That's a lot of delta-v. With some creative propulsion options, maybe even interstellar probes can be done.
sneak 2y ago
Everything you said is right, but on-orbit refueling is of course theoretically possible, and isn’t THAT huge of a leap given what SpaceX has already accomplished. Let’s not forget the space lasers, or the chopstick catch, or Starlink-live-streamed 4K views from the plasma shadow during reentry, or autonomous Dragon docking, etc. Sure, it’s hard, but that is perhaps the best engineering team in the history of humankind, and I think they’re up to the task. Additionally, people much smarter than me ALSO think they are up to the task, and they have more and higher-resolution data about the problem space, too. My money’s on they get it working. Maybe it takes five years or a dozen failures, but I’m confident that they will succeed eventually and there will be orbiting methane and lox fuel stations sooner rather than later.

perihelions 2y ago

- "A fully refueled Starship in LEO should have around 5km/s in an expendable configuration." That can't be right; a naive application of the rocket equation gives (3.72 km/s) * ln(1,300 mT / 100 mT) = 9.55 km/s.

TrainedMonkey 2y ago
It's definitely higher than 5km/s, but I would not go up to 9.5km/s. My napkin math was - booster provides 2km/s and the LEO is 7.2km/s, so if the ship arrives nearly empty LEO it must provide a minimum 5.2km/s. I did not account for gravity + friction losses which could be guesstimated to 2km/s. If we assume that ship handles all of them (which is not true booster does some) we come up to 5 + 2 = 7.2km/s. The equation you have uses block 1 prop + dry mass numbers. Block 1 does not have significant payload capability and the last one just flow on OFT 6. As such let's use Block 2 numbers, first one should fly early next year. Dry mass target 100t, payload 100t, prop mass 1,500t. So (3.72 km/s) * ln(1700 / 200) = 7.96 km /s. This is with using min advertised payload of 100t and Elon's forward looking 100t number for dry mass. Way above 5km/s, but reaching 9.5km/s with 100t of payload will be challenging. I've pulled stats from https://en.wikipedia.org/wiki/SpaceX_Starship https://en.wikipedia.org/wiki/SpaceX_Starship .
- perihelions 2y ago
  You're mixing up unrelated concepts. In particular, the payload capacity to LEO of 100 tonnes has nothing to do with this calculation. Europa Clipper isn't a 100 tonne payload; it's about 6.